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UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, DC 20549

_______________________________

FORM 10-K
(Mark One)
[X] Annual report pursuant to Section 13 or 15(d) of the Securities Exchange
Act of 1934 for the fiscal year ended December 31, 1999

or
[_] Transition report pursuant to Section 13 or 15(d) of the Securities
Exchange Act of 1934 for the transition period from _______________ to
_______________

Commission File Number 0-23441
------------------------------

POWER INTEGRATIONS, INC.
(Exact name of registrant as specified in its charter)


DELAWARE 94-3065014
(State or other jurisdiction of (I.R.S. Employer
Incorporation or organization) Identification No.)

477 N. Mathilda Avenue, California 94086
(Address of principal executive offices) (Zip code)

(408) 523-9200
(Registrant's telephone number, including area code)

Securities registered pursuant to Section 12(b) of the Act:

Title of each class Name of Exchange on which registered
------------------- ------------------------------------
None None

Securities registered pursuant to Section 12(g) of the Act:

Common Stock, $.001 par value
(Title of Class)

_______________________________

Indicate by check mark whether the registrant (1) has filed all reports
required to be filed by Section 13 or 15(d) of the Securities Act of 1934 during
the preceding 12 months (or for such shorter period that the registrant was
required to file such reports), and (2) has been subject to such filing
requirements for the past 90 days. YES [X] NO [_]

Indicate by check mark if disclosure of delinquent filers pursuant to Item
405 of Regulation S-K is not contained herein, and will not be contained, to the
best of registrant's knowledge, in definitive proxy or information statements
incorporated by reference in Part III of this Form 10-K or any amendment to this
Form 10-K. [X]

The aggregate market value of registrant's voting and non-voting common
equity held by nonaffiliates of registrant, based upon the closing sale price of
the common stock on February 29, 2000, as reported on the NASDAQ National
Market, was approximately $906,146,914. Shares of common stock held by each
officer, director and holder of 5% or more of the outstanding common stock have
been excluded in that such persons may be deemed to be affiliates. This
determination of affiliate status is not necessarily a conclusive determination
for other purposes.

Outstanding shares of registrant's common stock, $.001 par value, as of
February 29, 2000: 26,847,260

DOCUMENTS INCORPORATED BY REFERENCE

Parts of the definitive Proxy Statement for registrant's 2000 Annual
Meeting of Stockholders to be filed with the Commission pursuant to Regulation
14A not later than 120 days after the end of the fiscal year covered by this
Form are incorporated by reference into Part III of this Form 10-K Report.

================================================================================
PART I

This report includes a number of forward-looking statements. Such
statements reflect our current views with respect to future events and our
potential financial performance and are subject to risks and uncertainties that
could cause our actual results and financial position to differ materially from
what we say in this report. These factors include, but are not limited to, our
ability to maintain and establish strategic relationships; the risks inherent in
the development and delivery of complex technologies; our ability to attract,
retain and motivate qualified personnel; the emergence of new markets for our
products and services, and our ability to compete in those markets based on
timeliness, cost and market demand; and our limited financial resources. We more
fully discuss these and other risk factors in "Item 7--Management's Discussion
and Analysis of Financial Condition and Operating results--Risk Factors" and
elsewhere in this report.

TOPSwitch, TinySwitch and EcoSmart are trademarks of Power Integrations,
Inc.

Item 1. Business

Overview

We design, develop, manufacture and market proprietary, high-voltage,
analog integrated circuits, commonly referred to as ICs, for use primarily in
alternating current to direct current, or AC to DC, power conversion. We have
targeted high-volume power supply markets including:

. the cellular telephone market;
. the personal computer market;
. the cable and direct broadcast satellite decoder box market; and
. various other consumer and industrial electronics markets.

Our ICs cost-effectively bring the benefits of high levels of integration
to AC to DC switching supplies. We believe that the products in our TOPSwitch
family of high-voltage ICs, introduced in 1994, were the first highly integrated
power conversion ICs to achieve widespread market acceptance. We introduced
TOPSwitch II, an enhanced family of our ICs, in April 1997 and TinySwitch, a
family of more energy-efficient power conversion ICs, in September 1998.

Industry Background

Virtually every electronic device that plugs into a wall socket requires
some type of power supply to convert high-voltage AC, provided by electric
utilities, into low-voltage DC required by the devices. Additionally,
rechargeable, portable products, such as cellular phones and laptop computers,
also need an AC to DC power supply to recharge their batteries.

Before 1970, AC to DC power supplies used large, inefficient transformers,
which operated at low frequencies to convert power from AC to DC. In the 1970s,
the invention of high-voltage discrete semiconductors enabled the development of
a new generation of AC to DC "switching" power supplies, which allowed the use
of smaller, more efficient transformers to lower the voltage. Although these
discrete switchers offered advantages over older technologies, over the years
they have not kept pace with the technological advances made in the electronic
devices they power.

As the pressures from market forces have increased, the limitations of
discrete switchers have become more pronounced. Discrete switchers require
numerous components which limit the power supply designers' ability to reduce
the size, increase the functionality and improve the efficiency of switchers
while at the same time meeting stringent market cost and energy efficiency
requirements. In addition, discrete switchers involve a high level of

2
design complexity, which limits the scalability of designs and increases
time-to-market and development risks for new products.

Early attempts to replace discrete switchers with integrated switchers,
using high-voltage analog ICs, did not achieve widespread acceptance in the
marketplace because they were not cost-effective. We addressed this opportunity
in 1994 by introducing our first cost effective IC, TOPSwitch. Our growth since
that time validates our belief that a substantial market opportunity exists for
high-voltage ICs that are cost effective and combine the benefits of integration
that discrete switcher and earlier transformer technologies lack.

Our Highly Integrated Solution

We have developed several families of high-voltage power conversion ICs,
which we believe are the first highly integrated power conversion ICs to achieve
widespread market acceptance. Since introducing our TOPSwitch family of products
in 1994, we have shipped approximately 350 million TOPSwitch ICs, 150 million of
which were shipped in 1999. These patented ICs achieve a high level of system
integration by combining a number of electronic components into a single IC. Our
TOPSwitch and TinySwitch products enable many power supplies in the 0.5 to 150-
watt power range to have a total cost equal to or lower than discrete switchers.
Our TOPSwitch and TinySwitch products offer the following key benefits to power
supplies:

. Fewer Components, Reduced Size and Enhanced Functionality

Our highly integrated TOPSwitch ICs enable the design and
production of cost-effective switchers that use up to 50% fewer
components and have enhanced functionality compared to discrete-
based solutions. For example, our ICs provide thermal and short
circuit protection without increasing system cost, while discrete
switchers must add additional components and cost to provide these
functions.

. Improved Efficiency

Our integrated circuit also improves electrical efficiency, which
reduces power consumption and excess heat generation. Our patented
low-loss, high-voltage device, combined with its control circuitry,
improves overall electrical efficiency during both full operation
and stand-by mode.

. Reduced Time-to-Market

Our integrated circuit makes power supply design simpler and once
customers have created designs using our ICs, they can apply that
design to new products, resulting in a shorter time-to-market and
reduced product development risk.

. Wide Power Range and Scalability

Products in our current TOPSwitch families can address a power
range of 0.5 to 150 watts. The scalable architecture of these ICs
allows switcher designers to adapt their existing TOPSwitch-based
designs to a wide range of products to address many different power
supply markets.

Strategy

Our objective is to be the leading provider of high-voltage power
conversion ICs. We intend to pursue the following strategies to accelerate
adoption of our products:

3
.    Target High-Volume Markets

Because of our products' scalability and ability to address a wide
power range, a small number of products address a wide variety of
customer needs, allowing us to take advantage of economies of scale
and making us more competitive.

. Focus on Markets that Can Derive Significant Benefits from Integration

We are initially focusing our efforts on those markets that are
particularly sensitive to size, portability, energy efficiency and
time to market issues. We achieved early success in the cellular phone
fast charger market, as cellular phone customers demanded more
portable travel chargers instead of stand-alone desktop chargers. We
have also achieved some success in the desktop PC market due to the
market's demand for stand-by power capability, and in the cable and
direct broadcast satellite decoder box market due to that market's
need for reducing component count and for shortening product design
cycles. As other markets emerge as significant opportunities for our
TOPSwitch products, we intend to focus our resources on the
development and penetration of those markets.

. Deliver Systems Solution and Provide Applications Expertise

To help potential customers decide to purchase our TOPSwitch products,
we offer comprehensive application design support. We provide
extensive application notes and production-ready reference design
boards. We also provide application-engineering support out of our
headquarters and through field application engineering labs located in
China, England, Germany, India, Japan, Korea, Singapore and Taiwan. We
have committed substantial resources to system support by dedicating
approximately 30% of our technical workforce to applications
engineering. We believe our power supply systems expertise and
investment in field applications engineering provide us significant
competitive advantages.

. Extend Technological Leadership in High-Voltage Analog ICs

Our proprietary device structures and fabrication processes as well as
analog circuit designs have resulted in 25 U.S. patents and 33 foreign
patents. These patents, in combination with our other intellectual
property, form the basis of our TOPSwitch and TinySwitch product
families. We recently introduced an enhanced TOPSwitch product family
that provides improved power capability and system cost advantages
while preserving the design simplicity of our original TOPSwitch
products. We continue to improve our device structures, wafer
fabrication processes and analog circuit designs and seek to obtain
additional patents to protect our intellectual property.

. Leverage Patented Technology in Strategic Relationships

We have established relationships with Matsushita Electronics
Corporation, and with OKI Electric Industry in order to take advantage
of these companies' high volume manufacturing resources, and in the
case of Matsushita, generate royalty revenues. Our wafer manufacturing
relationships with Matsushita and OKI enable us to focus on
fundamental high-voltage silicon technology, product design and
marketing while minimizing fixed costs and capital expenditures.
Matsushita also has licensed the right to manufacture our products for
sale in certain geographic regions and for use in its own products.

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Products

Below is a brief description of our products:

. The TOPSwitch Product Families

Our TOPSwitch high-voltage analog IC products are able to meet the
power conversion needs of a wide range of applications within high
volume markets. Sales of TOPSwitch products accounted for 93%, 95% and
97% of our net revenues in 1997, 1998 and 1999, respectively.

. TOPSwitch

The TOPSwitch family consists of 13 products, the first of
which was introduced in 1994. The key benefits of the
TOPSwitch family compared to discrete switchers include
fewer components, reduced size, enhanced functionality and
lower cost in many applications. Our TOPSwitch products
integrate a PWM controller, a high-voltage MOSFET and a
number of other electronic components into a single 3
terminal IC. These products are produced in two high-voltage
versions--a 350-volt version for the 115VAC-switcher
markets, including the United States and Japan, and a 700-
volt version for the 230VAC-switcher markets, including
Europe.

. TOPSwitch II

The TOPSwitch II family currently consists of 11 products,
the first of which was introduced in April 1997. The
TOPSwitch II products further lower the switcher costs by
improving the performance of TOPSwitch and addressing low
power applications. The TOPSwitch II family uses the same
proprietary architecture as the original TOPSwitch family,
enabling switcher designers experienced with TOPSwitch to
take advantage of the TOPSwitch II benefits without
implementing a new architecture.

. TinySwitch

The TinySwitch family currently consists of 5 products, the
first of which was introduced in September 1998. The
TinySwitch family of high voltage ICs is the first of our
new generation chips based on our new EcoSmart technology.
We developed our EcoSmart technology to enable a new class
of light, compact, energy-efficient power supplies to
address the growing global demand to reduce energy waste in
a wide range of electronic products. The TinySwitch product
line topology was specifically designed to address low power
applications of less than 10 watts.

. Other Products

Our products also include our SMP family, our INT family and a limited
number of custom products. Sales of these products accounted for 7%,
5% and 3% of our net revenues in 1997, 1998 and 1999, respectively. We
expect revenue from these products to continue to decline as a
percentage of net revenues.

. SMP

The SMP family is the original line of power conversion
products, which we developed for the AC to DC power supply
market. These products are used in applications where
switcher designers are willing to pay a premium price for
additional features such as variable frequency.

5
.    INT

The INT products are interface drivers for motor control
applications, which utilize our high-voltage process
technology.

. Custom Products

We also manufacture a limited number of custom products,
including a hook switch for telephones.

6
Markets and Customers

Our strategy is to target high-volume power supply markets and to initially
focus on markets that can benefit the most from our highly integrated power
conversion ICs. The following chart shows representative customers and end users
of our products in power supplies in several major market segments.

<TABLE>
<CAPTION>
Market Segment Customers
- ------------------------------------------------------- ----------------------------------------------------
<S> <C>
. Cellular Phones

Battery Chargers Eastcom, Ericsson, Hyundai, ICC, Lucky Goldstar,
Motorola and its subsidiaries, Mitsubishi, Nokia,
Phihong Enterprises, Sagem, Samsung Electronics,
Tamura

. Desktop Computers

Stand-by Power Acbel (API), Artesyn, Astec, Compaq, Dell, Delta
Electronics, Hewlett Packard, Hipro, IBM, Intertek,
Liteon, Minebea, Magnetek, SPI, Tiger

. Cable and Direct Broadcast Satellite

Set-top Decoders Acbel (API), Amstrad, General Instruments, Grundig,
Hughes, Magnetek, Nokia, Pace, Pioneer, Samsung,
Scientific Atlanta, Sony

. PC Peripherals

Multi-media Monitor & Audio Harman, JBL, Logitech, Lucky Goldstar, Sony
Universal Serial Bus Nokia, Philips, Samsung, Sony
Removable Mass Storage Iomega, Electronique D2, Imation

. Consumer

TV Daewoo, Lucky Goldstar, Philips, Samsung, Sharp,
Sony, Tatung, Vestel, Xocexo, Zenith
VCR Aiwa, Daewoo, Sony
DVD Shinco, Thakral

. Industrial

Utility Meters Landis & Gyr, MTC, Schlumberger, Siemens
Uninterrupted Power Supply APC, Exide Electronics

. Home Appliances

Washing Machines, Air AKO-Werke, Fisher-Paykel, Kelon, Lucky Goldstar,
Conditioners, Dish Washers, Meide, Miele, Samsung, Shanghai Sinyuan
Vacuum Cleaners
</TABLE>

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Description of Our Primary Markets

. Cellular Phone Chargers

In the cellular phone market, size, portability and more recently,
energy efficiency are key market drivers for these products. We
believe a substantial market opportunity exists for small, energy
efficient power supplies for battery chargers. We estimate the
total available annual market for cell phone chargers was
approximately 300 million units in 1999.

. Desktop Computer Standby Power Supplies

Governmental authorities are promoting computer manufacturers to
use highly efficient stand-by power in new PCs to reduce the PCs'
power consumption when idle. Our TOPSwitch and TinySwitch products
are currently being used in computers to reduce the power consumed
when idle and to meet the market demand for more energy-efficient
computers. We estimate that the annual market for standby power
supplies for desktop PCs was approximately 90 million units in
1999.

. Cable and Direct Broadcast Satellite Decoder Boxes

Cable and direct broadcast satellite decoder box manufacturers are
particularly sensitive to component count, printed circuit board
space and the ability to shorten their product design cycles. Our
TopSwitch products are currently help them solve these problems and
provide other benefits inherent with an integrated solution. We
estimate that the annual market for power supplies in cable and
direct broadcast satellite decoder boxes was approximately 25
million units in 1999.

. Other Markets

Although we currently focus on the above key markets, we also sell
products into a wide variety of other markets, which include PC
peripherals, televisions, VCRs, industrial meters and home
appliances. As these and other markets emerge as significant
opportunities for our IC products, we intend to focus our resources
on the development and penetration of these markets.

Sales, Distribution and Marketing

We sell our products to original equipment manufacturers, OEMs, and
merchant power supply manufacturers through a direct sales staff and through a
worldwide network of independent sales representatives and distributors. We use
sales representatives throughout Asia and Europe. Our international sales
representatives also act as distributors. In the United States, we use one
national distributor and a number of regional sales representatives. We have
sales offices in Laguna Beach, California, Marietta, Georgia and, Wakefield,
Massachusetts, as well as in China, England, Germany, India, Korea and Taiwan.
For 1999, direct sales to OEMs and merchant power supply manufacturers
represented approximately 60% of our net revenues while sales through
distributors accounted for the remaining 40%. All distributors are entitled to
certain return privileges based on sales revenue and are protected from price
reductions affecting their inventories. Our distributors are not subject to
minimum purchase requirements and the sales representatives and distributors can
discontinue marketing any of our products at any time.

Our products are generally incorporated into a customer's power supply at
the design stage. Our sales and marketing efforts are focused on facilitating
the customer's use of our products in the design of new power supplies for
specific applications. An important competitive factor in determining whether a
customer decides to use our products in its designs is our commitment to provide
comprehensive application design support. We publish comprehensive databooks and
design guides and provide to our current and prospective customers extensive
application notes and production-ready reference design boards. In addition, we
provide application-engineering support out of our headquarters, and our field
application engineering labs provide local resources to

8
support customers in key geographies. We focus particular efforts on building
relationships with, and providing support to, industry-leading OEMs and merchant
power supply manufacturers. We have committed substantial resources to system
support by dedicating approximately 30% of our technical workforce to
applications engineering.

Our end user base is highly concentrated, and a relatively small number of
OEMs, directly or indirectly through merchant power supply manufacturers,
accounted for a significant portion of our revenue in 1998 and 1999. Motorola is
presently our largest end user. Although the exact dollar amounts and
percentages of sales to Motorola are difficult to ascertain because most of such
sales occur through distributors or indirectly through sales to merchant power
supply manufacturers which, in turn, sell power supplies to Motorola, we
estimate that direct and indirect sales to Motorola accounted for approximately
23% of our net revenues for 1999. We estimate that our top ten customers,
including distributors which resell to Motorola and other large OEMs and
merchant power supply manufacturers, accounted for 67%, 67% and 68% of our net
revenues for 1997, 1998 and 1999, respectively. For 1997, Maxisum (Insight), a
distributor, and Phihong Enterprise, a merchant, accounted for 21% and 15% of
our net revenues, respectively. For 1998, Maxisum and Synnex Technologies, both
distributors, accounted for 22% and 13% of our net revenues, respectively. For
1999, these two distributors accounted for 16% and 11% of our net revenues,
respectively. No other customers accounted for more than 10% of net revenues
during 1997, 1998 and 1999. In 1997, 1998 and 1999, international sales
comprised 81%, 83% and 78%, respectively, of our net revenues.

Sales of our products are generally made pursuant to standard purchase
orders, which are frequently revised to reflect changes in the customer's
requirements. Product deliveries are scheduled upon our receipt of purchase
orders. Generally, these orders allow customers to reschedule delivery dates and
cancel purchase orders without significant penalties. For these reasons, we
believe that purchase orders received, while useful for scheduling production,
are not necessarily reliable indicators of future revenues.

In the Japanese market, we have a license agreement with Matsushita under
which Matsushita sells its versions of our products. While we continue to sell
products to our existing Japanese customers, in April 1997, as part of the
license agreement, we agreed not to pursue new business in Japan until after
June 2000. We believe that this arrangement will better meet our market
penetration and financial objectives in Japan. We support Matsushita's sales
efforts and our existing Japanese customers through our office in Japan.

Technology

. High-Voltage Transistor Structure and Process Technology

We have developed a proprietary high-voltage, power IC technology,
which uses our MOS transistor structure and proprietary process and
has resulted in 7 U.S. patents. The technology enables us to
integrate cost effectively on the same monolithic IC, high-voltage
n-channel transistors with industry standard CMOS and bipolar
components. The IC device structure and the wafer fabrication
process both contribute to the cost effectiveness of our high-
voltage technology. The device structure results in a transistor
conduction capability that is significantly higher than that of
competing technologies. The IC device structure can be implemented
on low cost silicon wafers using relatively large feature sizes, up
to a 3 micron CMOS process, when combined with our proprietary
implant process step.

. IC Design and System Technology

Our proprietary IC designs combine complex control circuits and
high-voltage transistors on the same monolithic IC and have
resulted in 17 U.S. patents. Our IC design technology takes
advantage of our high-voltage process to minimize the die size of
both the high-voltage device and control circuits and improve the
performance of our ICs versus alternative integration technologies.
The combination of our IC design technology and our system level
expertise in switchers has enabled us to develop the highly
integrated TOPSwitch ICs and scalable architecture for integrated
switchers.

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Research and Development

Our research and development efforts are focused on improving our high-
voltage device structures, wafer fabrication processes, analog circuit designs
and system level architecture. By these efforts, we seek to further reduce the
costs of our products, and improve the cost effectiveness and enhance the
functionality of our customers' power supplies. We have assembled a
multidisciplined team of highly skilled engineers to meet our research and
development goals. These engineers bring expertise in high-voltage structure and
process technology, analog design and power supply systems architecture.

In 1997, 1998 and 1999, we spent $5.3 million, $7.2 million and $10.8
million, respectively, on research and development efforts. We expect to
continue to invest substantial funds in research and development activities. The
development of high-voltage analog ICs is highly complex. We cannot guarantee
that we will develop and introduce new products in a timely and cost-effective
manner or that our development efforts will successfully permit our products to
meet changing market demands.

Intellectual Property and Other Proprietary Rights

We use a combination of patents, trademarks, copyrights, trade secrets and
confidentiality procedures to protect our intellectual property rights. We hold
25 U.S. patents and have generally filed for or received foreign patent
protection on these patents resulting in 33 foreign patents to date. The U.S.
patents have expiration dates ranging from 2006 to 2019. Seven of the U.S.
patents are related to the device structure of the high-voltage transistor, ten
are circuit patents that have been used in our products and three are circuit
patents that provide the foundation for our TOPSwitch products. Two of the U.S.
patents cover specific system applications using TOPSwitch. Additionally, we
have three new circuit patents which we believe will provide a basis for future
products. We are currently pursuing additional U.S. patent applications relating
to improvements and extensions of our products. We cannot guarantee that our
pending United States or foreign patent applications or any future United States
or foreign patent applications will be approved, that any issued patents will
protect our intellectual property or will not be challenged by third parties, or
that the patents of others will not have an adverse effect on our ability to do
business. Furthermore, we cannot guarantee that others will not independently
develop similar or competing technology or design around any of our patents. We
also hold nine trademarks, five in the U.S., two in California and two in Japan.

We regard as proprietary certain equipment, processes, information and
knowledge that we have developed and used in the design and manufacture of our
products. Our trade secrets include a proprietary high volume production process
that produces our patented high-voltage ICs. We attempt to protect our trade
secrets and other proprietary information through non-disclosure agreements,
proprietary information agreements with employees and consultants and other
security measures. Despite these efforts, we cannot guarantee that others will
not gain access to our trade secrets, or that we can meaningfully protect our
intellectual property. In addition, effective trade secret protection may be
unavailable or limited in certain foreign countries. Although we intend to
protect our rights vigorously, we cannot assure that such measures will be
completely successful.

We have granted a perpetual non-transferable license to Matsushita to use
our semiconductor patents and other intellectual property for our current high-
voltage technology, including our TOPSwitch technology and improvements on the
existing technology, which allows Matsushita to manufacture and design products
for internal use and for sale or other distribution to Japanese companies and to
subsidiaries of Japanese companies in Asia. To the extent the products they
manufacture and design are not based on the TOPSwitch technology, Matsushita may
make sales or other distribution to Asian companies in Asia. Matsushita has
granted us perpetual cross licenses to the technology developed by them under
their license rights. We have agreed not to license the technology licensed to
Matsushita to other Japanese companies or their subsidiaries prior to June 2000.
We have also agreed not to sell our products in Japan to new customers. In
exchange for its license rights, Matsushita has paid and will continue to pay to
us licensing fees for a fixed period and has paid or will pay royalties on
products using the licensed technology during fixed periods. In April 1997, we
amended our license agreement with Matsushita to explicitly include high-voltage
device technology being developed by us in return for an improved royalty
structure from Matsushita.

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We have also granted a perpetual, non-transferable license to AT&T
Microelectronics to use certain of our IC processes and device technologies in
the products AT&T sells. In addition, pursuant to an agreement with MagneTek,
Inc., we have granted MagneTek an exclusive, perpetual royalty-free license to
manufacture lighting products that incorporate certain of our technology.

Manufacturing

We contract with Matsushita and OKI to manufacture our wafers in foundries
located in Japan. Our semiconductor products are assembled and packaged by
independent subcontractors in China, Malaysia and the Philippines. We perform
testing, finishing and shipping at our facility in Sunnyvale, California. This
fabless manufacturing model enables us to focus on our engineering and design
strengths, minimize fixed costs on capital expenditures, and still have access
to high-volume manufacturing capacity. Our products do not require leading edge
process geometries for them to be cost-effective, and thus we can use
Matsushita's and OKI's older, low-cost facilities for wafer manufacturing. We
use a proprietary and sensitive implant process and must interact closely with
Matsushita and OKI to achieve satisfactory yields. Although we generally utilize
standard IC packages for assembly, some materials and aspects of assembly are
specific to our products. We require our manufacturers to use a high-voltage
molding compound that is difficult to process and is available from only one
supplier. This compound and its required processes, together with the other non-
standard materials and processes needed to assemble our products, require a more
exacting level of process control than normally required for standard packages.
As a result we must be involved with our contractors on an active engineering
basis to maintain and improve the process. We have developed process monitoring
equipment to support this effort and must provide adequate engineering resources
to provide similar support in the future.

Our wafer supply agreements with Matsushita and OKI expire in June 2000 and
September 2003, respectively. Under the terms of our agreement with Matsushita,
we establish minimum annual and monthly purchase and sale commitments annually
with the mutual agreement of Matsushita. We also establish pricing by good faith
agreement, subject to our right to most favored pricing. Under the terms of the
OKI agreement, OKI has agreed to reserve a specified amount of production
capacity and to sell wafers to us at fixed prices. Our agreements with both
Matsushita and OKI provide for the purchase of wafers in Japanese yen.

We cannot assure you that we will be able to reach an agreement with
Matsushita to extend the term of its wafer supply agreement. Failure to reach,
in a timely fashion, an extension of our agreement with Matsushita or to enter
into an arrangement with another manufacturer could result in material
disruptions in supply. Contractual provisions limit the conditions under which
we can enter into such arrangements with other Japanese manufacturers or their
subsidiaries during the term of the agreement with Matsushita. In the event of a
supply disruption with OKI or Matsushita, if we were unable to quickly qualify
alternative manufacturing sources for existing or new products or if these
sources were unable to produce wafers with acceptable manufacturing yields, our
operating results would suffer.

We typically receive shipments from Matsushita or OKI approximately 8 to 10
weeks after placing orders, and lead times for new products can be substantially
longer. To provide sufficient time for assembly, testing and

11
finishing, we typically need to receive wafers from Matsushita and OKI 4 to 6
weeks before the desired ship date to our customers. As a result of these
factors and the fact that customers' orders can be made with little advance
notice, we have only a limited ability to react to fluctuations in demand for
our products. This could cause us to have an excess or a shortage of inventory
of a particular product. From time to time in the past we have been unable to
fully satisfy customer requests as a result of these factors. Any significant
disruptions in deliveries would materially adversely affect our business and
operating results. We carry a substantial amount of inventory of tested wafers
to help offset these factors to better serve our markets and meet customer
demand.

Competition

The high-voltage power supply industry is intensely competitive and
characterized by extreme price sensitivity. Accordingly, the most significant
competitive factor in the target markets for our products is cost effectiveness.
Our products face competition from alternative technologies, including
traditional linear transformers and discrete switcher power supplies. We believe
that at current pricing, our families of high-voltage power conversion ICs offer
favorable cost-performance benefits compared to linear and discrete switcher
supplies in many high-volume applications. However, there has been sizeable
overcapacity of discrete components, which resulted in significant price erosion
for these products during 1998 and 1999. A continuation of the price decline of
discrete components, such as high-voltage Bipolar and MOSFET transistors and PWM
controller ICs, could adversely affect the cost effectiveness of the TOPSwitch
products. Also, older alternative technologies like linear transformers are more
cost-effective than discrete switchers and integrated switchers that use our ICs
in certain power ranges for certain applications. If power requirements for
certain applications in which our products are currently utilized, such as
battery chargers for cellular telephones, drop below certain power levels, these
older alternative technologies can be used more cost effectively than switchers.
Our TinySwitch IC family, introduced in September 1998, was specifically
designed to enhance the cost effectiveness of our integrated switcher solutions
in the low power range. However, we cannot guarantee that our efforts in this
area will be successful.

Recently, our TOPSwitch product families have begun to meet increased
competition from hybrid and single high-voltage ICs similar to TOPSwitch. These
competing products are being developed or have been developed and are being
produced by companies such as ON Semiconductor, STMicroelectronics, Fairchild
Semiconductor and Sanken Electric Company. We expect competition to increase as
companies like these see the success we have had in converting older
technologies to the integrated solutions enabled by our product offerings. To
the extent these competitors' products are more cost effective than our
products, our business, financial condition and operating results could be
materially adversely affected. Many of our emerging competitors, including
Motorola, STMicroelectronics, Samsung and Sanken, have significantly greater
financial, technical, manufacturing and marketing resources than do we. In the
context of a market where a high-voltage IC is designed into a customer's
product and the provider of such ICs is therefore the sole source of the IC for
that product, greater manufacturing resources may be a significant factor in the
customer's choice of the IC because of the customer's perception of greater
certainty in its source of supply.

Our ability to compete in our target markets also depends on such factors
as:

. timing and success of new product introductions by us and our
competitors;

. the pace at which our customers incorporate our products into their end
user products;

. availability of wafer fabrication and finished good manufacturing
capability;

. availability of adequate sources of raw materials;

. protection of our products by effective utilization of intellectual
property laws; and

. general economic conditions.

We cannot assure you that our products will continue to compete favorably
or that we will be successful in the face of increasing competition from new
products and enhancements introduced by existing competitors or

12
new companies entering this market. Our failure to compete successfully in the
high-voltage power supply business would materially adversely affect our
business, financial condition and operating results.

Employees

As of December 31, 1999, we employed 220 full time personnel, consisting of
88 in manufacturing, 61 in research and development, 50 in sales and marketing
and 21 in finance and administration.

Executive Officers of Power Integrations

As of February 29, 2000, our executive officers, which are elected by and
serve at the discretion of the board of directors, were as follows:

<TABLE>
<CAPTION>
Name With Power Integrations Age
- ---------------------- -------------------------------------------------------------- ---
<S> <C> <C>
Howard F. Earhart President, Chief Executive Officer and Chairman of the Board 60

Balu Balakrishnan Vice President, Engineering and Strategic Marketing 45

Roderick D. Davies Vice President, Operations 49

Joyce Engberg Vice President, Information Technology 50

Richard S. Fassler Vice President, Marketing 48

Vladimir Rumennik Vice President, Technology Development 54

Daniel M. Selleck Vice President, Worldwide Sales 53

Robert G. Staples Chief Financial Officer, Vice President, Finance and 52
Administration and Secretary

Clifford J. Walker Vice President, Corporate Development 48

Alan D. Bickell(1)(2) Director 63

Nicholas E. Brathwaite Director 41

R. Scott Brown(1) Director 58

E. Floyd Kvamme(1)(2) Director 62

Steven J. Sharp Director 58
</TABLE>

- ---------------

(1) Member of the compensation committee

(2) Member of the audit committee

Howard F. Earhart has served as our president, chief executive officer and
as a director since January 1995. From July 1994 to March 1995, Mr. Earhart
served as chief executive officer of Co-Active Computing, a personal computer
peer-to-peer network adapter company. From July 1994 to January 1995, Mr.
Earhart served as chief executive officer of Reach Software, a software company.

Balu Balakrishnan has served as our vice president, engineering and
strategic marketing since September 1997. From September 1994 to September 1997,
Mr. Balakrishnan served as our vice president, engineering and marketing. Mr.
Balakrishnan served as our vice president, design engineering from April 1989 to
September 1994.

Roderick D. Davies has served as our vice president, operations since
August 1999. In the previous eight years Mr. Davies held various positions,
including vice president of the business unit management, and marketing and
operations positions at International Rectifier, a worldwide supplier of power
semiconductors used for power conversion.

13
Joyce Engberg has served as our vice president, information technology
since February 1999. From January 1996 to January 1999, Ms. Engberg served as
chief information officer of Spectrian, a manufacturer of RF power amplifiers.
From January 1993 to January 1996, Ms. Engberg served as director of technical
services of Consilium, a software company.

Richard S. Fassler has served as our vice president, marketing since
January 2000. From 1986 to 2000, Mr. Fassler held various positions, most
recently as the vice president of sales and marketing at IXYS Corporation, a
designer and developer of power semiconductors.

Vladimir Rumennik has served as our vice president, technology development
since April 1991. From February 1990 to March 1991, Mr. Rumennik was our
director of technology development. Prior to January 1990, Mr. Rumennik was a
manager at Signetics, a semiconductor company and a subsidiary of Philips
Semiconductor.

Daniel M. Selleck has served as our vice president, worldwide sales since
May 1993. From February 1984 to May 1993, Mr. Selleck held various sales
management positions with Philips Semiconductor including European regional
sales manager and western area sales manager in the United States.

Robert G. Staples has served as our chief financial officer, vice
president, finance and administration and secretary since June 1995. From
October 1994 to June 1995, Mr. Staples served as chief financial officer of MIS,
a software development company. From October 1993 to October 1994, Mr. Staples
served as chief financial officer of Simtec Corporation, a semiconductor
company.

Clifford J. Walker has served as our vice president, corporate development
since June 1995. From September 1994 to June 1995, Mr. Walker served as vice
president of Reach Software, a software company. From December 1993 to September
1994, Mr. Walker served as president of Morgan Walker, a consulting company.

Alan D. Bickell has served as a member of the board of directors since
April 1999. Mr. Bickell retired in 1996 after more than 30 years with Hewlett
Packard, serving as a corporate senior vice president and managing director of
geographic operations since 1992.

Nicholas E. Brathwaite has served as a member of the board of directors
since January 2000. Mr. Brathwaite currently serves as senior vice president and
chief technology officer for Flextronics International, a provider of
engineering, advanced electronics manufacturing and logistical services, and has
held various engineering management positions with Flextronics since 1995. From
1989 to 1995, Mr. Brathwaite held various management positions at nChip, a
multi-chip module company.

R. Scott Brown has served as member of the board of directors since July
1999. From 1985 to May 1999, Mr. Brown served as senior vice president of
worldwide sales and support for Xilinx, Inc., a designer and developer of
complete programmable logic solutions for use by electronic equipment
manufacturers.

E. Floyd Kvamme has served as a member of the board of directors since
September 1989. Mr. Kvamme has been a general partner of Kleiner Perkins
Caufield & Byers, a venture capital company, since 1984. Mr. Kvamme also serves
on the boards of Brio Technology, Harmonic Inc., National Semiconductor, Photon
Dynamics and several private companies.

Steven J. Sharp is one of our founders and has served as a member of the
board of directors since our inception. Mr. Sharp has served as president, chief
executive officer and chairman of the board of TriQuint Semiconductor, a
manufacturer of gallium arsenide integrated circuits, since September 1991.

14
Item 2.   Properties.

Our main executive, administrative, manufacturing and technical offices are
located in a 30,000 square foot facility in Sunnyvale, California under a lease
which expires in October 2003 with a conditional five-year option at fair market
value to the year 2008. Our manufacturing operations at this facility consist of
testing wafers and ICs. We have also acquired an additional 15,000 square foot
facility in Sunnyvale, California, which is leased through June 2003. On
December 29, 1999, we entered into a new lease for an 118,000 square foot
facility located in Hellyer Oaks Technology Park in San Jose, California, which
will become available in mid 2000, at which time we will relocate our Sunnyvale
operations to that site. The lease on the new facility has a term of 10 years,
expiring in May 2010 with two conditional five-year options, which if exercised
would extend the lease to May 2020.

Item 3. Legal Proceedings.

In July 1998, we filed a complaint for patent infringement in the U.S.
District Court, Northern District of California, against our largest end user,
Motorola. In August 1998, we voluntarily dismissed the complaint, and filed a
new complaint in the U.S. District Court, District of Delaware, alleging that
Motorola has infringed and continues to infringe two of our circuit patents. In
October 1998, Motorola asserted various counterclaims against us, alleging that
we are infringing certain of Motorola's patents.

Trial of this action was held in October 1999. On October 15, 1999, the
jury returned a unanimous verdict in our favor. The jury determined that
Motorola had willfully infringed one of our patents and awarded us $32.3 million
in compensatory damages. The jury also found that we had not infringed any of
the asserted Motorola patents and that two of the Motorola patents were invalid.
In March 2000, we entered into a settlement agreement with Motorola. Pursuant to
the settlement agreement, the court has issued a permanent injunction
prohibiting Motorola from selling the ICs that were the subject of the lawsuit.
Additionally, we will not collect the money judgment from Motorola and will
continue as a preferred supplier of high-voltage power conversion ICs for
cellular phone chargers that Motorola manufactures. The companies will work more
closely together to develop future generations of cellular phone chargers for
Motorola.

Item 4. Submission of Matters to a Vote of Security Holders.

None.

15
PART II

Item 5. Market for Power Integration's Common Equity and Related Stockholder
Matters.

Our common stock trades on the Nasdaq National Market under the symbol
"POWI." As of February 29, 2000, there were approximately 131 stockholders of
record. Because brokers and other institutions on behalf of stockholders hold
many of such shares, we are unable to estimate the total number of stockholders
represented by these record holders. The following table sets forth, for the
quarter indicated, the range of daily closing prices per share of our common
stock as reported on the Nasdaq National Market:

Price Range
----------------------
Year Ended December 31, 1999 High Low
---------------------------- --------- ---------
Fourth quarter $56.687 $34.875
Third quarter $38.625 $25.968
Second quarter $36.562 $14.218
First quarter $17.187 $10.750

Year Ended December 31, 1998 High Low
---------------------------- ------- -------
Fourth quarter $13.562 $ 5.625
Third quarter $ 6.781 $ 4.250
Second quarter $ 7.187 $ 4.062
First quarter $ 7.125 $ 4.687


All prices per share have been adjusted to reflect the 2-for-1 stock split
we effected on November 22, 1999.

We have not paid any cash dividends on our capital stock. We currently
intend to retain our earnings for use in the operation and expansion of our
business and, therefore, do not anticipate paying any cash dividends in the
foreseeable future.

16
Item 6.   Selected Financial Data.

The following selected consolidated financial data should be read in
conjunction with "Management's Discussion and Analysis of Financial Condition
and Results of Operations" and the Consolidated Financial Statements and the
Notes thereto included elsewhere in this Form 10-K.

<TABLE>
<CAPTION>
Years Ended December 31,
-----------------------------------------------------------
1999 1998 1997 1996 1995
---- ---- ---- ---- ----
<S> <C> <C> <C> <C> <C>
(in thousands, except per share data)
Consolidated Statement of Operations Data:
Net revenues:
Product sales........................................... $102,655 $68,206 $44,827 $23,324 $17,406
License fees and royalties.............................. 1,412 1,802 1,162 619 1,009
-------- ------- ------- ------- -------
Total net revenues................................... 104,067 70,008 45,989 23,943 18,415
Cost of revenues.......................................... 46,794 36,638 26,291 15,546 12,371
-------- ------- ------- ------- -------
Gross profit.............................................. 57,273 33,370 19,698 8,397 6,044
-------- ------- ------- ------- -------
Operating expenses:
Research and development................................ 10,764 7,231 5,253 3,519 2,044
Sales and marketing..................................... 11,085 8,468 6,417 3,905 2,744
General and administrative.............................. 8,760 3,641 2,053 1,558 1,619
-------- ------- ------- ------- -------
Total operating expenses............................. 30,609 19,340 13,723 8,982 6,407
-------- ------- ------- ------- -------
Income (loss) from operations............................. 26,664 14,030 5,975 (585) (363)
Interest and other income (expense), net.................. 2,147 1,248 (683) (726) (406)
-------- ------- ------- ------- -------
Income (loss) before provision for income taxes........... 28,811 15,278 5,292 (1,311) (769)
Provision for income taxes................................ 4,334 2,600 530 30 34
-------- ------- ------- ------- -------
Net income (loss)......................................... $ 24,477 $12,678 $ 4,762 $(1,341) $ (803)
======== ======= ======= ======= =======
Earnings (loss) per share:
Basic................................................... $0.94 $0.52 $1.26 $(0.78) $(0.69)
======== ======= ======= ======= =======
Diluted................................................. $0.87 $0.48 $0.25 $(0.78) $(0.69)
======== ======= ======= ======= =======
Shares used in per share calculation:
Basic................................................... 25,958 24,426 3,776 1,712 1,170
======== ======= ======= ======= =======
Diluted................................................. 28,197 26,452 18,678 1,712 1,170
======== ======= ======= ======= =======
<CAPTION>
December 31,
-----------------------------------------------------------
1999 1998 1997 1996 1995
---- ---- ---- ---- ----
(in thousands)
<S> <C> <C> <C> <C> <C>
Consolidated Balance Sheet Data:
Cash, cash equivalents and short-term investments......... $ 61,672 $44,418 $29,008 $ 7,692 $ 3,800
Working capital........................................... 71,169 42,988 30,131 9,769 7,435
Total assets.............................................. 98,571 65,054 48,559 19,535 15,279
Long-term debt and capitalized lease obligations, net of
current portion.......................................... 1,393 1,963 2,435 5,499 2,219
Stockholders' equity...................................... 80,248 47,364 33,327 9,098 9,512
</TABLE>

17
Item 7.  Management's Discussion and Analysis of Financial Condition and
Operating results.

This Management's Discussion and Analysis of Financial Condition and Operating
results includes a number of forward-looking statements which reflect our
current views with respect to future events and financial performance. These
forward-looking statements are subject to certain risks and uncertainties,
including those discussed in the "Risk Factors" and elsewhere in this report
that could cause actual results to differ materially from historical results or
those anticipated. In this report, the words "anticipates," "believes,"
"expects," "future," "intends," and similar expressions identify forward-looking
statements. We caution you not to place undue reliance on these forward-looking
statements, which speak only as of the date of this report.

Overview

We design, develop, manufacture and market proprietary, high-voltage, analog
ICs for use in AC to DC power conversion primarily for the cellular telephone,
personal computer, cable and direct broadcast satellite and various consumer
electronics markets. From our inception in March 1988 through 1993, we developed
numerous standard and custom products incorporating high levels of features and
functionality, each intended to address the needs of various markets. Although
we succeeded in developing the core of our patented technology during this
period, market penetration of our products was low because these products were
not as cost-effective as alternative products. Limited product revenue and the
high costs associated with developing and marketing numerous solutions to
numerous target markets resulted in our being unprofitable.

In 1993, we changed our strategy to focus on bringing cost-effective,
integrated products to the high-voltage AC to DC power supply markets. As a
result, in 1994, we completed development of TOPSwitch, the first in our family
of cost effective, high voltage, power conversion ICs. The TOPSwitch family of
products, with its proprietary integrated architecture, is designed to address
with relatively few products broad applications in a number of high-volume,
high-voltage AC to DC power supply markets. The initial target markets served by
TOPSwitch are particularly sensitive to size, portability, energy efficiency and
time-to-market. The TOPSwitch products and the solutions enabled by them are
significantly lower in cost than our previous products and the solutions enabled
by those products. Commercial shipments of TOPSwitch began in May 1994.
Primarily as a result of the increasing sales of TOPSwitch products, our net
revenues from product sales more than tripled between 1994 and 1995, increasing
from $5.0 million to $17.4 million. Net revenues from product sales increased
sequentially by 34% in 1996, 92% in 1997, 52% in 1998 and 51% in 1999.

By focusing on the TOPSwitch family of products, we were able to more
effectively utilize our resources and limit the growth of operating expenses in
1994 and 1995. Because of this and the growth in net revenues, operating
expenses were reduced from 77.5% of net revenues in 1994 to 34.8% of net
revenues in 1995. In response to increasing market acceptance of our TOPSwitch
products and faster revenue growth in 1996, we accelerated our investment in
research and development and sales and marketing, including technical customer
support. As a result, operating expenses were $9.0 million in 1996, $13.7
million in 1997, $19.3 million in 1998 and $30.6 million in 1999. Operating
expenses in 1999 included approximately $4.1 million in additional legal costs
related to the lawsuit filed against Motorola. Our legal expenses associated
with the Motorola litigation are expected to decline in future quarters.
However, we expect that all of our other operating expenses will increase in
absolute dollars, but will fluctuate as a percentage of net revenues, as we
continue to add resources to research and development, sales and marketing and
general and administrative activities.

Our quarterly and annual operating results are volatile and difficult to
predict. Our net revenues and operating results have varied significantly in the
past, are difficult to forecast and are subject to numerous factors both within
and outside of our control, As a result, our quarterly and annual operating
results may fluctuate significantly in the future. For a discussion of the
factors that may effect our quarterly and annual operating results, please see
Factors that May Affect Future Results of Operations.

18
We license certain technologies and grant limited product manufacturing and
marketing rights to strategic parties in return for foundry relationships,
license fees and product royalty arrangements. Prior to the introduction of
TOPSwitch in 1994, our analog ICs generated limited product sales while license
fees and prepaid royalties accounted for a significant percentage of our total
revenues. In future periods, we expect license fees and royalties to consist
primarily of royalties on products shipped by licensees incorporating licensed
technology, and anticipate that license fees and royalties will account for a
small percentage of net revenues.

A portion of our cost of revenues consists of the cost of wafers. The contract
prices to purchase wafers from Matsushita and OKI are denominated in Japanese
yen. Changes in the exchange rate between the U.S. dollar and the Japanese yen
subject our gross profit and operating results to the potential for material
fluctuations. From time to time, as these strategic parties close old production
lines and move to new fabrication facilities, we must absorb a portion of the
costs of physically moving the manufacturing of our products to new production
lines, including the costs of installation of new process technologies.

Product revenues consist of sales to OEMs and merchant power supply
manufacturers and to distributors. Revenues from product sales to OEMs and
merchant power supply manufacturers are recognized upon shipment. At that time,
we provide for estimated sales returns and other allowances related to those
sales. Between 40 and 50 percent of our sales are made to distributors under
terms allowing certain rights of return and price protection for our products
held in the distributors' inventories. Therefore, we defer recognition of
revenue and the proportionate cost of revenues derived from sales to
distributors until the distributors resell our products to their customers. The
gross profit deferred as a result of this policy is reflected as "deferred
income on sales to distributors" on our consolidated balance sheet. See note 2
of notes to consolidated financial statements.

Results of Operations

The following table sets forth certain operating data as a percentage of total
net revenues for the periods indicated.

<TABLE>
<CAPTION>
Percentage of
Total Net Revenues
For the Years Ended December 31,
----------------------------------------
1999 1998 1997
---- ---- ----
<S> <C> <C> <C>
Net revenues:
Product sales.......................................................... 98.6% 97.4% 97.5%
License fees and royalties............................................. 1.4 2.6 2.5
----- ----- -----
Total net revenues.................................................. 100.0 100.0 100.0
Cost of revenues......................................................... 45.0 52.3 57.2
----- ----- -----
Gross profit............................................................. 55.0 47.7 42.8
----- ----- -----
Operating expenses:
Research and development............................................... 10.3 10.3 11.4
Sales and marketing.................................................... 10.7 12.1 14.0
General and administrative............................................. 8.4 5.2 4.4
----- ----- -----
Total operating expenses............................................ 29.4 27.6 29.8
----- ----- -----
Income from operations................................................... 25.6 20.1 13.0
Interest and other income (expense), net................................. 2.1 1.8 (1.5)
----- ----- -----
Income before provision for income taxes................................. 27.7 21.9 11.5
Provision for income taxes............................................... 4.2 3.7 1.1
----- ----- -----
Net income............................................................... 23.5% 18.2% 10.4%
===== ===== =====
</TABLE>

19
Comparison of Years Ended December 31, 1998 and 1999


Net revenues. Net revenues consist of revenues from product sales, which are
calculated net of returns and allowances, plus license fees and royalties paid
by licensees of our technology. Net revenues increased 48.7% from $70.0 million
in 1998 to $104.1 million in 1999. Net revenues from product sales represented
$68.2 million and $102.7 million of net revenues in 1998 and 1999, respectively.
The increase in net revenues from product sales was due primarily to strong
demand for our products across all of our major markets and geographies. In
particular, sales to the cellular phone market accounted for approximately 39%
of our product revenues for 1999 compared to 26% of product revenues in 1998,
and increased 118% over 1998 sales to that market. Sales of our TOPSwitch and
TinySwitch products represented 97% and 95% of net revenues from product sales
in 1999 and 1998, respectively. Net revenues from royalties were $1.4 million in
1999 compared to $1.8 million in 1998. We expect net revenues from royalties to
continue to account for a small percentage of our net revenues.

International sales were $81.6 million in 1999 compared to $58.1 million in
1998, representing approximately 78% and 83% of net revenues in those respective
periods. Although the power supplies using our products are designed and
distributed worldwide, most of these power supplies are manufactured in Asia. As
a result, the largest portion of our net revenues is derived from sales to this
region. We expect international sales to continue to account for a large portion
of our net revenues.

In 1999, two separate customers accounted for approximately 16% and 11% of net
revenues. In 1998, the same customers accounted for approximately 22% and 13% of
net revenues, respectively. See note 2 of notes to consolidated financial
statements.

Cost of revenues; Gross profit. Gross profit is equal to net revenues less
cost of revenues. Our cost of revenues consists primarily of costs associated
with the purchase of wafers from Matsushita and OKI, the assembly and packaging
of our products, and internal labor and overhead associated with the testing of
both wafers and packaged components. These costs include expenses incurred in
connection with the physical move of the manufacturing of our products between
wafer production lines at our foundry suppliers and with the installation of new
process technologies at these foundries. These costs may recur from time to time
and adversely affect our cost of revenues.

Gross profit increased from $33.4 million, or 47.7% of net revenues in 1998,
to $57.3 million, or 55.0% of net revenues, in 1999. Efficiencies realized from
higher volumes, reductions in wafer costs, and improved test yields contributed
to the improvement in gross profit. Gross profit also benefited from a one-time
credit from one of our wafer suppliers in the amount of $1.4 million recorded in
1999. The credit improved our gross profit by 1.3% for the year. We cannot
assure you that these or other factors will have a favorable impact on our gross
profit in future periods.

Research and development expenses. Research and development expenses consist
primarily of employee-related expenses, and expensed material and facility costs
associated with the development of new processes and new products. We also
expense prototype wafers and mask sets related to new products as research and
development costs until new products are released to production. Research and
development expenses increased by approximately 48.9%, from $7.2 million in 1998
to $10.8 million in 1999. The increase was primarily the result of increased
salaries and other costs related to the hiring of additional engineering
personnel, outside consulting fees and expensed prototype materials resulting
from the transition of foundry manufacturing processes, and bringing newly
developed products into manufacturing. These expenses remained unchanged as a
percentage of net revenues at 10.3% in both 1998 and 1999.

Sales and marketing expenses. Sales and marketing expenses consist primarily
of employee-related expenses, commissions to sales representatives and
facilities expenses, including expenses associated with our regional sales and
support offices. Sales and marketing expenses increased approximately 30.9%,
from $8.5 million in 1998 to $11.1 million in 1999, which represented 12.1% and
10.7% of net revenues in each respective period. This increase in absolute
dollars represents the addition of personnel to support international sales and
field application engineers.

20
General and administrative expenses.  General and administrative expenses
consist primarily of employee-related expenses for administration, finance,
human resources and general management, as well as consulting, outside services,
legal and auditing expenses. In 1998 and 1999, general and administrative
expenses were $3.6 million and $8.8 million, respectively, which represented
5.2% and 8.4% of net revenues in each respective period. This increase in
general and administrative expenses was primarily attributable to increased
professional and legal expenses related to our patent infringement lawsuit filed
against Motorola.

Interest and other income, net. Interest and other income, net, was $1.2
million and $2.1 million in 1998 and 1999, respectively. The increase in other
income reflected additional interest income related to the increase in cash
equivalents and short-term investments from 1998 to 1999, and lower interest
expense related to a reduction in our capital equipment lease obligations.

Provision for income taxes. Provision for income taxes for 1998 and 1999
represents Federal, state and foreign taxes. The effective tax rate was 17% for
1998 and 15% for 1999. The difference between the statutory rate and our
effective tax rate for 1998 and 1999 is due to the impact of benefiting net
operating loss carryforwards, offset by the reduction in the deferred tax
valuation allowance. See note 7 of notes to consolidated financial statements.

Comparison of Years Ended December 31, 1997 and 1998

Net revenues. Net revenues increased 52.2% from $46.0 million in 1997 to $70.0
million in 1998. Net revenues from product sales represented $44.8 million and
$68.2 million of net revenues in 1997 and 1998, respectively. The increase in
net revenues from product sales was due primarily to increased sales of our
TOPSwitch family of products, which represented 95% of product sales in 1998.
The migration from TOPSwitch to TOPSwitch II resulted in TOPSwitch II accounting
for 45% of product sales in 1998 compared to 15% for 1997. We began commercial
shipment of TOPSwitch II in April 1997. Net revenues also grew because of an
increase in royalty revenues, from $1.2 million in 1997 to $1.8 million in 1998.

International sales increased by $20.9 million in 1998 compared to 1997,
growing from approximately 81% of net revenues in 1997 to approximately 83% of
net revenues in 1998. Although the power supplies using our products are
designed and distributed worldwide, most of these power supplies are
manufactured in Asia. As a result, the largest portion of our net revenues is
derived from sales to this region.

In 1998, two separate customers accounted for approximately 22% and 13% of net
revenues. In 1997, one of the same customers and one different customer
accounted for approximately 21% and 15% of net revenues, respectively. See note
2 of notes to consolidated financial statements.

Cost of revenues; Gross profit. Gross profit increased from $19.7 million, or
42.8% of net revenues, to $33.4 million, or 47.7% of net revenues, in 1997 and
1998, respectively. Efficiencies realized from higher volumes, reductions in
both wafers and packaging costs, improved test yields, and a favorable foreign
exchange rate between the U.S. dollar and the Japanese yen through most of the
year contributed to the improvement in gross profit.

Research and development expenses. Research and development expenses increased
by approximately 37.7%, from $5.3 million in 1997 to $7.2 million in 1998. The
increase was primarily the result of increased salaries and other costs related
to the hiring of additional engineering personnel, outside consulting fees and
expensed prototype materials resulting from the transition of foundry
manufacturing processes with Matsushita and OKI. These expenses decreased as a
percentage of net revenues from 11.4% in 1997 to 10.3% in 1998 due to increased
sales.

Sales and marketing expenses. Sales and marketing expenses increased
approximately 32%, from $6.4 million in 1997 to $8.5 million in 1998, which
represented 14.0% and 12.1% of net revenues, respectively. This increase
represented the addition of personnel to support international sales and field
application engineers.

21
General and administrative expenses. In 1997 and 1998, general and
administrative expenses were $2.1 million and $3.6 million, respectively, which
represented 4.4% and 5.2% of net revenues, respectively. This increase in
absolute dollars was primarily attributable to increased professional and legal
expenses related to our patent infringement lawsuit filed against Motorola.

Interest and other income (expense), net. Interest and other income
(expense), net, was $683,000 net expense in 1997 and $1.2 million net income in
1998. The net expense in 1997 reflected interest incurred on capital equipment
lease obligations and on $3.0 million of subordinated debt, which originated in
the second quarter of 1996, partially offset by interest income earned on cash
and short-term investments. The net income in 1998 reflected an increase in
interest income due to the increase in cash and short-term investments from 1997
to 1998, and the reduction in interest expense due to the repayment of the
subordinated debt in 1997.

Provision for income taxes. Provision for income taxes for 1997 and 1998
represented Federal, state and foreign taxes. The effective tax rate was 10% for
1997 and 17% for 1998 reflecting the profitable results for both years. The
difference between the statutory rate and our effective tax rate for 1997 and
1998 was due to the impact of benefiting net operating loss carryforwards,
offset by the reduction in the deferred tax valuation allowance. See note 7 of
notes to consolidated financial statements.

22
Selected Quarterly Results of Operations

The following tables set forth certain consolidated statement of operations
data for each of the quarters in the years ended December 31, 1999 and 1998 as
well as the percentage of our net revenues represented by each item. This
information has been derived from our unaudited consolidated financial
statements. The unaudited consolidated financial statements have been prepared
on the same basis as the audited consolidated financial statements contained
herein and include all adjustments, consisting only of normal recurring
adjustments, that we consider necessary for a fair presentation of such
information when read in conjunction with our annual audited consolidated
financial statements and notes thereto appearing elsewhere in this report. The
operating results for any quarter are not necessarily indicative of the results
for any subsequent period or for the entire fiscal year.

<TABLE>
<CAPTION>
Three Months Ended
--------------------------------------------------------------------------------
Dec. 31, Sept. 30, June 30, Mar. 31, Dec. 31, Sept. 30, June 30, Mar. 31,
1999 1999 1999 1999 1998 1998 1998 1998
---- ---- ---- ---- ---- ---- ---- ----
(in thousands, except per share data)
<S> <C> <C> <C> <C> <C> <C> <C> <C>
Net revenues:
Product sales............................... $29,725 $29,829 $22,655 $20,446 $19,750 $19,907 $14,647 $13,902
License fees and royalties.................. 402 311 324 375 402 410 466 524
------- ------- ------- ------- ------- ------- ------- -------
Total net revenues........................ 30,127 30,140 22,979 20,821 20,152 20,317 15,113 14,426
Cost of revenues............................. 14,178 12,667 10,482 9,467 9,773 10,635 8,254 7,976
------- ------- ------- ------- ------- ------- ------- -------
Gross profit................................. 15,949 17,473 12,497 11,354 10,379 9,682 6,859 6,450
------- ------- ------- ------- ------- ------- ------- -------
Operating expenses:
Research and development.................... 3,080 2,813 2,535 2,336 2,005 1,947 1,720 1,559
Sales and marketing......................... 2,988 2,893 2,729 2,475 2,479 2,376 1,724 1,889
General and administrative.................. 1,640 4,324 1,427 1,369 1,296 1,067 730 548
------- ------- ------- ------- ------- ------- ------- -------
Total operating expenses.................. 7,708 10,030 6,691 6,180 5,780 5,390 4,174 3,996
------- ------- ------- ------- ------- ------- ------- -------
Income from operations...................... 8,241 7,443 5,806 5,174 4,599 4,292 2,685 2,454
Interest and other income, net............... 620 510 433 584 473 399 189 187
------- ------- ------- ------- ------- ------- ------- -------
Income before provision for
Income taxes................................ 8,861 7,953 6,239 5,758 5,072 4,691 2,874 2,641
Provision for income taxes................... 1,346 1,185 939 864 865 351 721 663
------- ------- ------- ------- ------- ------- ------- -------
Net income................................... $ 7,515 $ 6,768 $ 5,300 $ 4,894 $ 4,207 $ 4,340 $ 2,153 $ 1,978
======= ======= ======= ======= ======= ======= ======= =======
Earnings per share
Basic....................................... $ 0.28 $ 0.26 $0.21 $ 0.19 $ 0.17 $ 0.18 $ 0.09 $ 0.08
Diluted..................................... $ 0.26 $ 0.24 $0.19 $ 0.18 $ 0.16 $ 0.17 $ 0.08 $ 0.08
Shares used in per share calculation
Basic....................................... 26,440 26,275 25,814 25,289 24,904 24,459 24,174 24,160
Diluted..................................... 28,916 28,589 28,183 27,425 27,074 26,256 26,118 26,261
</TABLE>

<TABLE>
<CAPTION>
Percentage of Total Net Revenues
--------------------------------------------------------------------------------------
Dec. 31, Sept. 30, June 30, Mar. 31, Dec. 31, Sept. 30, June 30, Mar. 31,
1999 1999 1999 1999 1998 1998 1998 1998
---- ---- ---- ---- ---- ---- ---- ----
<S> <C> <C> <C> <C> <C> <C> <C> <C>
Net revenues:
Product sales.............................. 98.7% 99.0% 98.6% 98.2% 98.0% 98.0% 96.9% 96.4%
License fees and royalties................. 1.3 1.0 1.4 1.8 2.0 2.0 3.1 3.6
----- ----- ----- ----- ----- ----- ----- -----
Total net revenues....................... 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0
Cost of revenues............................ 47.1 42.0 45.6 45.5 48.5 52.3 54.6 55.2
----- ----- ----- ----- ----- ----- ----- -----
Gross profit................................ 52.9 58.0 54.4 54.5 51.5 47.7 45.4 44.8
----- ----- ----- ----- ----- ----- ----- -----
Operating expenses:
Research and development................... 10.2 9.4 11.0 11.2 9.9 9.6 11.4 10.8
Sales and marketing........................ 9.9 9.6 11.9 11.9 12.3 11.7 11.4 13.1
General and administrative................. 5.4 14.3 6.2 6.6 6.4 5.3 4.8 3.8
----- ----- ----- ----- ----- ----- ----- -----
Total operating expenses................. 25.5 33.3 29.1 29.7 28.6 26.6 27.6 27.7
----- ----- ----- ----- ----- ----- ----- -----
Income from operations...................... 27.4 24.7 25.3 24.8 22.9 21.1 17.8 17.1
Interest and other income, net.............. 2.1 1.7 1.9 2.8 2.4 1.9 1.2 1.3
----- ----- ----- ----- ----- ----- ----- -----
Income before provision for income
Taxes...................................... 29.5 26.4 27.2 27.6 25.3 23.0 19.0 18.4
Provision for income taxes.................. 4.5 3.9 4.1 4.1 4.3 1.7 4.8 4.6
----- ----- ----- ----- ----- ----- ----- -----
Net income.................................. 25.0% 22.5% 23.1% 23.5% 21.0% 21.3% 14.2% 13.8%
===== ===== ===== ===== ===== ===== ===== =====
</TABLE>

23
Net revenues increased sequentially in the first, second and third quarters of
both 1999 and 1998, and were essentially unchanged from the third quarter to the
fourth quarter each year. Increases in product sales were due to growth in the
volume of sales from existing customers, the addition of new customers and the
introduction of the TinySwitch family of products in the third quarter of 1998.
Sequential net revenues were unchanged in the fourth quarters of 1999 and 1998
due, we believe, to the seasonal nature of some of our markets.

Our gross profit increased as a percentage of net revenues during each of the
seven quarters ended September 30, 1999 and was down in the quarter ended
December 31, 1999. The gross profit improvements generally were due to
efficiencies realized from higher volumes, reductions in material costs and
improved test yields. The third quarter of 1999 benefited approximately 4% from
a one-time credit from one of our wafer suppliers. The lower gross profit margin
in the fourth quarter was primarily due to continued pricing pressures from our
customers and a weakening dollar versus Japanese Yen.

Research and development expenses increased in absolute terms during the eight
quarters presented, primarily due to increased staffing in the areas of new
product design and technology development. Due to increases in net revenues,
research and development expenses remained relatively unchanged as a percent of
total net revenues.

Sales and marketing expenses generally increased in absolute dollars over the
eight quarters presented, primarily due to the additional staffing in sales and
application engineering and increased sales commissions due to the increased
revenues from product sales. Sales expenses were down in the first and second
quarters of 1998 due to reduced commissions because of lower seasonal net
revenues.

General and administrative expenses increased over the eight quarters
presented with significant increases from the third quarter of 1998 through the
end of 1999 primarily due to increased legal expense related to our patent
infringement lawsuit filed against Motorola.

Interest and other income, net essentially increased over the eight quarters
presented primarily from increased interest income due to higher cash balances
created by a net positive cash flow as well as cash proceeds from our initial
public offering in December 1997.

Liquidity and Capital Resources

Since our initial public offering of common stock in December 1997, our
principal source of funding has been cash from our operations with some funding
from capital equipment lease lines.

As of December 31, 1999, we had approximately $61.7 million in cash, cash
equivalents and short-term investments. In addition, under a revolving line of
credit agreement with Union Bank of California, we can borrow up to $10.0
million. A portion of the credit line is used to cover advances for commercial
letters of credit and standby letters of credit, which we provide to Matsushita
and OKI prior to the shipment of wafers by those foundries to us. The balance of
this credit line is unused and available. The line of credit agreement contains
financial covenants and requires that we maintain profitability on a quarterly
basis and not pay or declare dividends without the bank's prior consent. We have
financed a significant portion of our machinery and equipment through capital
equipment leases. We financed additional equipment during the year ended
December 31, 1999 in the amount of $772,000. We may obtain additional financing
for equipment purchases in future quarters. As of December 31, 1999, we owed
approximately $2.9 million on our various capital equipment leases.

As of December 31, 1999, we had working capital, defined as current assets
less current liabilities, of approximately $71.2 million, which was an increase
of approximately $28.2 million over December 31, 1998. Our operating activities
generated cash of $22.9 million and $18.5 million in the year ended December 31,
1999 and 1998, respectively. Cash generated in the year ended December 31, 1999
was principally the result of net income in the amount of $24.5 million,
depreciation and amortization, tax benefits from employee stock plans and
increases in accounts payable and accrued liabilities. This was partially offset
by increases in accounts

24
receivable, inventory and deferred income taxes. Cash generated in the year
ended December 31, 1998 was principally the result of net income of $12.7
million, depreciation and amortization, increases in deferred revenue, accounts
receivable and accrued liabilities, offset by an increase in inventories and a
decrease in accounts payable.

Our investing activities were a net transfer from cash and cash equivalents to
short-term investments of $13.5 million and $16.8 million for the years ended
December 31, 1999 and 1998, respectively. We also purchased capital assets in
the amount of $6.6 million and $2.0 million for the years ended December 31,
1999 and 1998, respectively.

We believe that cash generated from operations, together with existing sources
of liquidity, will satisfy our projected working capital and other cash
requirements for at least the next 12 months.

Year 2000 Readiness Disclosure

To date, we have not experienced any disruption in our products as a result
of, nor has any third-party vendor on whom we depend been affected by, the
commencement of the year 2000. Although we do not anticipate that our products
will be affected by the year 2000, if we, or our third-party providers, fail to
remedy any year 2000 issues, the result could be lost revenues, increased
operating expenses, the loss of customers and other business interruptions, any
of which could harm our business. The failure to adequately address year 2000
compliance issues in the delivery of products to our customers could result in
litigation against us, which could be costly and time consuming to defend.

In light of our experiences to date, we have not developed any further
contingency plans for year 2000 issues beyond those preparations made prior to
January 1, 2000. Our worst-case scenario for year 2000 problems would be our
inability to provide our products and services to our customers and resultant
decline in total revenues.

New Accounting Standards

In June 1998, the Financial Accounting Standards Board issued SFAS No. 133,
"Accounting for Derivative Instruments and Hedging Activities." SFAS No. 133
establishes accounting and reporting standards for derivative instruments,
hedging activities, and exposure definition. SFAS No. 133 requires companies to
recognize all derivatives as either assets or liabilities in the statement of
financial position and measure those instruments at fair value. SFAS No. 133 is
effective for all fiscal quarters of fiscal years beginning after June 15, 2000.
We do not expect the adoption of SFAS No. 133 to have a material impact on our
financial statements.

In December 1999, the Securities and Exchange Commission issued Staff
Accounting Bulletin No. 101 ("SAB 101"), "Revenue Recognition in Financial
Statements." SAB 101 provides guidance on applying generally accepted accounting
principles to revenue recognition issues in financial statements. We will adopt
SAB 101 as required in the first quarter of 2000 and are evaluating the effect
that such adoption may have on our consolidated results of operations and
financial position.

Factors That May Affect Future Results of Operations

In addition to the other information in this Report, the following factors
should be considered carefully in evaluating our business before purchasing
shares of our stock.

Our quarterly and annual operating results are volatile and difficult to
predict. If we fail to meet the expectations of public market analysts or
investors, the market price of our common stock may decrease significantly. Our
net revenues and operating results have varied significantly in the past, are
difficult to forecast, are subject to numerous factors both within and outside
of our control, and may fluctuate significantly in the future. As a result, our
quarterly operating results will likely fall below the expectations of public
market analysts or investors. If that occurs, the price of our stock may
decline.

25
Some of the factors that could affect our operating results include the
following:

. the volume and timing of orders received from customers;
. the volume and timing of orders placed by us with our foundries;
. changes in product mix including the impact of new product introduction
on existing products;
. our ability to develop and bring to market new products and technologies
on a timely basis;
. the timing of investments in research and development and sales and
marketing;
. cyclical semiconductor industry conditions; and
. fluctuations in exchange rates, particularly the exchange rates between
the U.S. dollar and the Japanese yen.

Our quarterly results may be subject to seasonality. Historically, our
revenues are strongest in our third and fourth quarters, due to what we believe
are seasonal factors attributed to the high volume consumer markets for the end
products into which our ICs are sold. Our revenues have then followed a pattern
of being sequentially linear or somewhat down in the first and second quarters
of the next year.

We do not have long-term contracts with any of our customers and if they fail
to place, or if they cancel or reschedule orders for our products, our operating
results and business may suffer. Our business is characterized by short-term
customer orders and shipment schedules. The ordering patterns of some of our
existing large customers have been unpredictable in the past and we expect that
customer-ordering patterns will continue to be unpredictable in the future. Not
only does the volume of units ordered by particular customers vary substantially
from period to period, but also purchase orders received from particular
customers often vary substantially from early oral estimates provided by those
customers for planning purposes. In addition, customer orders can be canceled or
rescheduled without significant penalty to the customer. In the past we have
experienced customer cancellations of substantial orders for reasons beyond our
control, and significant cancellations could occur again at any time.

We depend on Motorola for a significant portion of our net revenues and if we
lose Motorola as a customer, our operating results will suffer. For 1999,
direct sales to Motorola accounted for approximately 9% of our net revenues.
Indirect sales, through power supply merchants, which incorporate our ICs into
the products they produce for Motorola, accounted for approximately 13% of our
net revenues. For the quarter ended December 31, 1999, direct sales and indirect
sales to Motorola accounted for approximately 8% and 16% of our net revenues,
respectively. We expect that our operating results, in part, will depend on our
direct and indirect sales to Motorola for the foreseeable future.

Intense competition in the high-voltage power supply industry may lead to a
decrease in the average selling price and reduced sales volume of our products,
which may harm our business. The high-voltage power supply industry is
intensely competitive and characterized by significant price erosion. Our
products face competition from alternative technologies, including traditional
linear transformers and discrete switcher power supplies. If the price of
competing products decreases significantly, the cost effectiveness of our
products will be adversely affected. If power requirements for applications in
which our products are currently utilized, including battery chargers for
cellular telephones, drop below current power levels, these older alternative
technologies can be used more cost effectively than our TOPSwitch-based
switchers.

26
We cannot assure you that our products will continue to compete favorably or
that we will be successful in the face of increasing competition from new
products and enhancements introduced by existing competitors or new companies
entering this market. We believe our failure to compete successfully in the
high-voltage power supply business, including our ability to introduce new
products with higher average selling prices, would materially harm our operating
results.

If demand for our products declines in the cellular phone battery charger and
desktop personal computer stand-by markets, our net revenues will decrease.
Applications of our products in the cellular phone battery chargers and desktop
personal computer, or PC, stand-by markets have and will continue to account for
the majority of our net revenues. We expect that our net revenues and operating
results will continue to be substantially dependent upon these markets for the
foreseeable future. The cellular phone and desktop PC markets can be highly
cyclical and have been subject to significant economic downturns at various
times. Any significant downturn in these markets could cause our net revenues to
decline and the price of our stock to fall. In addition, technological advances
in these markets may reduce demand for our products.

Because the sales cycle for our products can be lengthy, we may incur
substantial expenses before we generate significant revenues, if any. Our
products are generally incorporated into a customer's products at the design
stage. However, customer decisions to use our products, commonly referred to as
design wins, which can often require us to expend significant research and
development and sales and marketing resources without any assurance of success,
often precede volume sales, if any, by a year or more. The value of any design
win will largely depend upon the commercial success of the customer's product.
We cannot assure you that we will continue to achieve design wins or that any
design win will result in future revenues. If a customer decides at the design
stage not to incorporate our products into its product, we may not have another
opportunity for a design win with respect to that product for many months or
years.

Our products must meet exacting specifications, and undetected defects and
failures may occur which may cause customers to return or stop buying our
products. Our customers generally establish demanding specifications for
quality, performance and reliability that our products must meet. ICs as complex
as those we sell often encounter development delays and may contain undetected
defects or failures when first introduced or after commencement of commercial
shipments. We have from time to time in the past experienced product quality,
performance or reliability problems. If defects and failures occur in our
products, we could experience lost revenue, increased costs, including warranty
expense and costs associated with customer support, delays in or cancellations
or rescheduling of orders or shipments and product returns or discounts, any of
which would harm our operating results.

We depend on third-party suppliers to provide us with wafers for our products
and if they fail to provide us sufficient wafers, our business will suffer. We
have supply arrangements for the production of wafers with Matsushita and OKI.
Although certain aspects of our relationships with Matsushita and OKI are
contractual, many important aspects of these relationships depend on their
continued cooperation and, in many instances, their course of conduct deviates
from the literal provisions of the contracts. We cannot assure you that we will
continue to work successfully with Matsushita or OKI in the future, that they
will continue to provide us with sufficient capacity at their foundries to meet
our needs, or that either of them will not seek an early termination of its
wafer supply agreement with us. Our contract with Matsushita terminates in June
2000, and if we cannot extend our agreement with Matsushita, our net revenues
may decline. We estimate that it would take 9 to 12 months from the time we
identified an alternate manufacturing source before that source could produce
wafers with acceptable manufacturing yields in sufficient quantities to meet our
needs.

Although we provide Matsushita and OKI with rolling forecasts of our
production requirements, their ability to provide wafers to us is limited by the
available capacity of the foundry in which it manufactures wafers for us. An
increased need for capacity to meet internal demands or demands of other
customers could cause Matsushita and OKI to reduce capacity available to us.
Matsushita and OKI may also require us to pay amounts in excess of contracted or
anticipated amounts for wafer deliveries or require us to make other concessions
in order to acquire the wafer supply necessary to meet our customers'
requirements. Any of these concessions could harm our business.

27
If our third-party suppliers and independent subcontractors do not produce our
wafers and assemble our finished products at acceptable yields, our net revenues
may decline. We depend on Matsushita and OKI to produce wafers, and independent
subcontractors to assemble finished products, at acceptable yields and to
deliver them to us in a timely manner. The failure of Matsushita or OKI to
supply us wafers at acceptable yields could prevent us from selling our products
to our customers and would likely cause a decline in our net revenues. In
addition, our IC assembly process requires our manufacturers to use a high-
voltage molding compound available from only one vendor, which is difficult to
process. This compound and its required processes, together with the other non-
standard materials and processes needed to assemble our products, require a more
exacting level of process control than normally required for standard packages.
Unavailability of the sole source compound or problems with the assembly process
can materially adversely affect yields and cost to manufacture. We cannot assure
you that acceptable yields will be maintainable in the future.

Matsushita has licenses to our technology, which it may use to our detriment.
Our ability to take advantage of the potentially large Japanese market for our
products is largely dependent on Matsushita and its ability to promote and
deliver our products. Pursuant to our agreement with Matsushita, Matsushita has
the right to manufacture and sell products using our technology to Japanese
companies worldwide and to subsidiaries of Japanese companies located in Asia.
In addition, we have agreed not to sell our products in Japan to new customers.
Although we receive royalties on Matsushita's sales, these royalties are
substantially lower than the gross profit we would receive on direct sales. We
cannot assure you that Matsushita will not use the technology rights we have
granted it to develop or market competing products following any termination of
its relationship with us or after termination of Matsushita's royalty obligation
to us.

Our international sales activities subject us to substantial risks. Sales to
customers outside of the United States account for a large portion of our net
revenues. These sales involve a number of risks to us, including:

. potential insolvency of international distributors and representatives;
. reduced protection for intellectual property rights in some countries;
. the impact of recessionary environments in economies outside the United
States;
. tariffs and other trade barriers and restrictions; and
. the burdens of complying with a variety of foreign laws.

Our failure to adequately address these risks could reduce our international
sales, which would materially adversely affect our operating results.
Furthermore, because substantially all of our foreign sales are denominated in
U.S. dollars, increases in the value of the dollar increase the price in local
currencies of our products in foreign markets and make our products relatively
more expensive and less price competitive than competitors' products that are
priced in local currencies.

If our efforts to enhance existing products and introduce new products are not
successful, we may not be able to generate demand for our products. Our success
depends in significant part upon our ability to develop new ICs for high-voltage
power conversion for existing and new markets, to introduce these products in a
timely manner and to have these products selected for design into products of
leading manufacturers. If we fail to develop and sell new products in a timely
manner, our net revenues could decline.

We cannot be sure that we will be able to adjust to changing market demands as
quickly and cost-effectively as necessary to compete successfully. Furthermore,
we cannot assure you that we will be able to introduce new products in a timely
and cost-effective manner or in sufficient quantities to meet customer demand or
that these products will achieve market acceptance. Our or our customers'
failure to develop and introduce new products successfully and in a timely
manner would harm our business and may cause the price of our common stock to
fall. In addition, customers may defer or return orders for existing products in
response to the introduction of new

28
products. Although we maintain reserves against returns, we cannot assure you
that these reserves will be adequate.

If our products do not penetrate additional markets, our business will not
grow as we predict. We believe that our future success depends in part upon our
ability to penetrate additional markets for our products. We cannot assure you
that we will be able to overcome the marketing or technological challenges
necessary to do so. To the extent that a competitor penetrates additional
markets before we do, or takes market share from us in our existing markets, our
net revenues and financial condition could be materially adversely affected.

If we are unable to adequately protect or enforce our intellectual property
rights, we could lose market share, incur costly litigation expenses or lose
valuable assets. Our success depends upon our ability to protect our
intellectual property, including patents, trade secrets, and know-how, and to
continue our technological innovation. We cannot assure you that the steps we
have taken to protect our intellectual property will be adequate to prevent
misappropriation or that others will not develop competitive technologies or
products. From time to time we have received, and we may receive in the future,
communications alleging possible infringement of patents or other intellectual
property rights of others. Litigation, which could result in substantial cost to
us, may be necessary to enforce our patents or other intellectual property
rights or to defend us against claimed infringement of the rights of others. The
failure to obtain necessary licenses or other rights or litigation arising out
of infringement claims could cause us to lose market share and harm our
business.

Moreover, the laws of some foreign countries in which our technology is or may
in the future be licensed may not protect our intellectual property rights to
the same extent as the laws of the United States, thus increasing the
possibility of infringement of our intellectual property.

We must attract and retain qualified personnel to be successful and
competition for qualified personnel is intense in our market. Our success
depends to a significant extent upon the continued service of our executive
officers and other key management and technical personnel, and on our ability to
continue to attract, retain and motivate qualified personnel, such as
experienced systems applications engineers. The competition for these employees
is intense, particularly in Silicon Valley. The loss of the services of one or
more of our engineers, executive officers or other key personnel or our
inability to recruit replacements for these individuals or to otherwise attract,
retain and motivate qualified personnel could harm our business. We do not have
long-term employment contracts with, and we do not have in place key person life
insurance policies on, any of our employees.

Our recent growth has strained our resources and if we fail to successfully
manage this growth, we may lose customers. We have experienced a period of
rapid growth and expansion, which has placed, and continues to place, a
significant strain on our resources. Relationships with our customers generally
require significant engineering support. A significant increase in the number of
customers using our technology will increase the strain on our resources,
particularly our engineers. These strains may result in delays or difficulties
in our research and development process, which could impede our ability to
develop future generations of our products and to remain competitive. In
addition, any future periods of rapid growth or expansion could be expected to
place a significant strain on our limited managerial, financial and engineering
resources.

We have adopted anti-takeover measures, which may make it more difficult for a
third party to acquire us. Our board of directors has the authority to issue up
to 3,000,000 shares of preferred stock and to determine the price, rights,
preferences and privileges of those shares without any further vote or action by
the stockholders. The rights of the holders of common stock will be subject to,
and may be adversely affected by, the rights of the holders of any preferred
stock that may be issued in the future. The issuance of shares of preferred
stock, while potentially providing flexibility in connection with possible
acquisitions and for other corporate purposes, could have the effect of making
it more difficult for a third party to acquire a majority of our outstanding
voting stock. We have no present intention to issue shares of preferred stock.

In February 1999, our board of directors adopted a preferred stock purchase
rights plan intended to guard against hostile takeover tactics. The adoption of
this plan was not in response to any proposal to acquire us, and

29
the board is not aware of any such effort. The existence of this plan could have
the effect of making it more difficult for a third party to acquire a majority
of our outstanding voting stock.

The future trading price of our common stock could be subject to wide
fluctuations in response to a variety of factors. The price of our common stock
has been, and is likely to be, volatile. Factors including future announcements
concerning us or our competitors, quarterly variations in operating results,
announcements of technological innovations, the introduction of new products or
changes in our product pricing policies or those of our competitors, proprietary
rights or other litigation, changes in earnings estimates by analysts and other
factors could cause the market price of our common stock to fluctuate
substantially. In addition, stock prices for many technology companies fluctuate
widely for reasons which may be unrelated to operating results. These
fluctuations, as well as general economic, market and political conditions, may
harm the market price of our common stock.

30
Item 7A. Quantitative and Qualitative Disclosure About Market Risks

Interest Rate Risk. Our exposure to market risk for changes in interest rates
relate primarily to our investment portfolio. We do not use derivative financial
instruments in our investment portfolio. We invest in high-credit quality
issuers and, by policy, limit the amount of credit exposure to any one issuer.
As stated in our policy, we ensure the safety and preservation of our invested
principal funds by limiting default risk, market risk and reinvestment risk. We
mitigate default risk by investing in safe and high-credit quality securities
and by constantly positioning our portfolio to respond appropriately to a
significant reduction in a credit rating of any investment issuer, guarantor or
depository. The portfolio includes only marketable securities with active
secondary or resale markets to ensure portfolio liquidity.

The table below presents principal amounts and related weighted average
interest rates for our investment portfolio at December 31, 1999. All
investments mature, by policy, in 15 months or less.

(in thousands, except average interest rates)

<TABLE>
<CAPTION>
Average
Carrying Interest
Amount Rate
-------- --------
<S> <C> <C>
Cash Equivalents:
U.S. corporate securities......................................................... $ 5,488 6.64%
Tax-exempt securities............................................................. 20,500 4.33%
-------

Total cash equivalents....................................................... 25,988 4.82%
-------

Short-term Investments:
U.S. corporate securities......................................................... 17,897 5.28%
Foreign securities................................................................ 3,079 4.97%
Tax-exempt securities............................................................. 11,999 3.73%
-------

Total short-term investments................................................. 32,975 4.68%
-------

Total investment securities.................................................. $58,963 4.74%
=======
</TABLE>

Foreign Currency Exchange Risk. We transact business in various foreign
countries. Our primary foreign currency cash flows are in Japan and Western
Europe. Currently, we do not employ a foreign currency hedge program utilizing
foreign currency forward exchange contracts as the foreign currency transactions
and risks to date have not been significant.

Item 8. Consolidated Financial Statements and Supplementary Data.

The Financial Statements and Supplementary Data required by this item are set
forth at the pages indicated at Item 14(a).

Item 9. Changes in and Disagreements With Accountants on Accounting and
Financial Disclosure.

None.

31
PART III

The SEC allows us to include information required in this report by referring
to other documents or reports we have already or will soon be filing. This is
called "Incorporation by Reference." We intend to file our definitive proxy
statement pursuant to Regulation 14A not later than 120 days after the end of
the fiscal year covered by this report, and certain information therein is
incorporated in this report by reference.

Item 10. Directors and Executive Officers of the Registrant.

The information required by this Item is incorporated by reference to
information set forth in our definitive proxy statement under the heading
"Proposal No. 1--Election of Directors" and in Part I of this report under the
heading "Executive Officers of the Registrant."

The information required by this Item with respect to compliance with Section
16(a) of the Securities Exchange Act of 1934 is incorporated by reference to
information set forth in the definitive Proxy Statement under the heading
"Executive Compensation and Other Matters."

Item 11. Executive Compensation.

The information required by this Item is incorporated by reference to
information set forth in our definitive proxy statement under the heading
"Executive Compensation and Other Matters."

Item 12. Security Ownership of Certain Beneficial Owners and Management.

The information required by this Item is incorporated by reference to
information set forth in our definitive proxy statement under the heading "Stock
Ownership of Certain Beneficial Owners and Management."

Item 13. Certain Relationships and Related Transactions.

The information required by this Item is incorporated by reference to
information set forth in our definitive proxy statement under the heading
"Certain Relationships and Related Transactions."

32
PART IV

Item 14. Exhibits, Financial Statement Schedules and Reports on Form 8-K.

(a) The following documents are filed as part of this Form:

1. Financial Statements

Page
----
Report of Independent Public Accountants...................... 34

Consolidated Balance Sheets................................... 35

Consolidated Statements of Operations......................... 36

Consolidated Statements of Stockholders' Equity............... 37

Consolidated Statements of Cash Flows......................... 38

Notes to Consolidated Financial Statements.................... 39

2. Financial Statement Schedules

All schedules have been omitted because the required information is not
present or not present in amounts sufficient to require submission of the
schedules or because the information required is included in the
Consolidated Financial Statements or Notes thereto.


3. Exhibits

See Index to Exhibits. The Exhibits listed in the accompanying Index to
Exhibits are filed as part of this report.

(b) Reports on Form 8-K

Form 8-K filed on March 12, 1999 with the Securities and Exchange
Commission.

Form 8-K/A filed on March 22, 1999 with the Securities and Exchange
Commission.

33
REPORT OF INDEPENDENT PUBLIC ACCOUNTANTS

To Power Integrations, Inc.:

We have audited the accompanying consolidated balance sheets of Power
Integrations, Inc. (a Delaware corporation) and subsidiaries as of December 31,
1999 and 1998, and the related consolidated statements of operations,
stockholders' equity and cash flows for each of the three years in the period
ended December 31, 1999. These financial statements are the responsibility of
the Company's management. Our responsibility is to express an opinion on these
financial statements based on our audits.

We conducted our audits in accordance with generally accepted auditing
standards. Those standards require that we plan and perform the audit to obtain
reasonable assurance about whether the financial statements are free of material
misstatement. An audit includes examining, on a test basis, evidence supporting
the amounts and disclosures in the financial statements. An audit also includes
assessing the accounting principles used and significant estimates made by
management, as well as evaluating the overall financial statement presentation.
We believe that our audits provide a reasonable basis for our opinion.

In our opinion, the financial statements referred to above present fairly, in
all material respects, the financial position of Power Integrations, Inc. and
subsidiaries as of December 31, 1999 and 1998, and the results of their
operations and their cash flows for each of the three years in the period ended
December 31, 1999, in conformity with generally accepted accounting principles.


ARTHUR ANDERSEN LLP

San Jose, California
January 18, 2000 (except with respect
to the matter discussed in Note 8, as to
which is dated March 14, 2000)

34
POWER INTEGRATIONS, INC.

CONSOLIDATED BALANCE SHEETS
AS OF DECEMBER 31, 1999 AND 1998

(In thousands, except share and per share amounts)

<TABLE>
<CAPTION>
1999 1998
-------- -------
ASSETS
CURRENT ASSETS:
<S> <C> <C>
Cash and cash equivalents.......................................................... $ 27,883 $24,176
Short-term investments............................................................. 33,789 20,242
Accounts receivable, net of allowances of $990 in 1999 and $1,293 in 1998.......... 9,682 4,640
Inventories........................................................................ 11,406 8,845
Prepaid expenses and other current assets.......................................... 5,339 812
-------- -------
Total current assets............................................................ 88,099 58,715
-------- -------

PROPERTY AND EQUIPMENT, AT COST:
Machinery and equipment............................................................ 21,632 14,716
Leasehold improvements............................................................. 1,394 1,158
-------- -------
23,026 15,874
Less: Accumulated depreciation and amortization.................................... (12,554) (9,535)
-------- -------
10,472 6,339
-------- -------
$ 98,571 $65,054
======== =======
LIABILITIES AND STOCKHOLDERS' EQUITY

CURRENT LIABILITIES:
Current portion of capitalized lease obligations................................... $ 1,228 $ 1,950
Accounts payable................................................................... 6,524 5,866
Accrued payroll and related expenses............................................... 3,994 2,394
Taxes payable and other accrued liabilities........................................ 1,818 2,951
Deferred income on sales to distributors........................................... 3,366 2,566
-------- -------
Total current liabilities....................................................... 16,930 15,727
-------- -------

CAPITALIZED LEASE OBLIGATIONS, net of current portion................................ 1,393 1,963
-------- -------

COMMITMENTS (NOTE 4)

STOCKHOLDERS' EQUITY:
Convertible Preferred Stock, $0.001 par value
Authorized--3,000,000 shares
Outstanding--none -- --
Common Stock, $0.001 par value
Authorized-- 40,000,000 shares
Outstanding--26,468,272 shares in 1999 and 24,994,128 shares in 1998............ 26 25
Additional paid-in capital......................................................... 65,553 57,276
Common stock warrants.............................................................. -- 12
Stockholder notes receivable....................................................... (201) (274)
Deferred compensation.............................................................. (181) (321)
Cumulative translation adjustment.................................................. (129) (57)
Retained earnings (deficit)........................................................ 15,180 (9,297)
-------- -------
Total stockholders' equity...................................................... 80,248 47,364
-------- -------
$ 98,571 $65,054
======== =======
</TABLE>

The accompanying notes are an integral part of these consolidated financial
statements.

35
POWER INTEGRATIONS, INC.

CONSOLIDATED STATEMENTS OF OPERATIONS
FOR THE YEARS ENDED DECEMBER 31, 1999, 1998 AND 1997

(In thousands, except per share amounts)

<TABLE>
<CAPTION>
1999 1998 1997
NET REVENUES: ----------- ------------ ------------
<S> <C> <C> <C>
Product sales........................................................... $102,655 $68,206 $44,827
License fees and royalties.............................................. 1,412 1,802 1,162
-------- ------- -------
Total net revenues................................................... 104,067 70,008 45,989
COST OF REVENUES.......................................................... 46,794 36,638 26,291
-------- ------- -------
GROSS PROFIT.............................................................. 57,273 33,370 19,698
-------- ------- -------
OPERATING EXPENSES:
Research and development................................................ 10,764 7,231 5,253
Sales and marketing..................................................... 11,085 8,468 6,417
General and administrative.............................................. 8,760 3,641 2,053
-------- ------- -------
Total operating expenses............................................. 30,609 19,340 13,723
-------- ------- -------
INCOME FROM OPERATIONS.................................................... 26,664 14,030 5,975
-------- ------- -------
OTHER INCOME (EXPENSE):
Interest income......................................................... 2,515 1,801 359
Interest expense........................................................ (302) (432) (832)
Other, net.............................................................. (66) (121) (210)
-------- ------- -------
Total other income (expense)......................................... 2,147 1,248 (683)
-------- ------- -------
INCOME BEFORE PROVISION FOR
INCOME TAXES.......................................................... 28,811 15,278 5,292
PROVISION FOR INCOME TAXES................................................ 4,334 2,600 530
-------- ------- -------
NET INCOME................................................................ $ 24,477 $12,678 $ 4,762
======== ======= =======
EARNINGS PER SHARE:
Basic................................................................... $ 0.94 $ 0.52 $ 1.26
======== ======= =======
Diluted................................................................. $ 0.87 $ 0.48 $ 0.25
======== ======= =======
SHARES USED IN PER SHARE CALCULATION:
Basic................................................................... 25,958 24,426 3,776
======== ======= =======
Diluted................................................................. 28,197 26,452 18,678
======== ======= =======
</TABLE>

The accompanying notes are an integral part of these consolidated financial
statements.

36
POWER INTEGRATIONS, INC.

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY
FOR THE YEARS ENDED DECEMBER 31, 1999, 1998 AND 1997

(In thousands)
<TABLE>
<CAPTION>
Convertible
Preferred Stock Common Stock
------------------- ---------------- Additional Stockholder
Paid-In Notes Deferred
Shares Amount Shares Amount Capital Warrants Receivable Compensation
-------- -------- ------ -------- ----------- --------- ------------ -------------
<S> <C> <C> <C> <C> <C> <C> <C> <C>
BALANCE AT
DECEMBER 31, 1996................. 91,728 $ 35,271 1,752 $ 565 $ -- $ 12 $ -- $ --
Issuance of Common
Stock under employee
stock option plan................ -- -- 2,099 982 3 -- (405) --
Issuance of Common
Stock in connection
with Public Offering............. -- -- 5,400 5 18,840 -- -- --
Conversion of Preferred
Stock to
Common Stock..................... (91,728) (35,271) 14,895 15 35,256 -- -- --
Change in par value............... -- -- -- (2,108) 2,108 -- -- --
Deferred compensation............. -- -- -- 566 -- -- -- (566)
Amortization of deferred
compensation..................... -- -- -- -- -- -- -- 105
Translation adjustment............ -- -- -- -- -- -- -- --
Net income........................ -- -- -- -- -- -- -- --
------- -------- ------ ------- ------- -------- ----------- -----
BALANCE AT
DECEMBER 31, 1997................. -- -- 24,146 25 56,207 12 (405) (461)
Issuance of Common
Stock under employee
stock option plan, net of
repurchases..................... -- -- 275 -- 247 -- -- --
Issuance of Common
Stock under employee
stock purchase plan.............. -- -- 184 -- 627 -- -- --
Exercise of warrants, net......... -- -- 389 -- 46 -- -- --
Proceeds of stockholder
note repayment................... -- -- -- -- -- -- 131 --
Income tax benefit from
employee stock option plan....... -- -- -- -- 240 -- -- --
Additional IPO costs.............. -- -- -- -- (91) -- -- --
Amortization of deferred
compensation..................... -- -- -- -- -- -- -- 140
Translation adjustment............ -- -- -- -- -- -- -- --
Net income........................ -- -- -- -- -- -- -- --
------- -------- ------ ------- ------- -------- ----------- -----
BALANCE AT
DECEMBER 31, 1998................. -- -- 24,994 25 57,276 12 (274) (321)
Issuance of Common
Stock under employee
stock option plan, net of
repurchases..................... -- -- 769 1 1,678 -- -- --
Issuance of Common
Stock under employee
stock purchase plan.............. -- -- 351 -- 1,267 -- -- --
Exercise of warrants, net......... -- -- 354 -- 12 (12) -- --
Proceeds of stockholder
note repayment................... -- -- -- -- -- -- 73 --
Income tax benefit from
employee stock option plan....... -- -- -- -- 5,320 -- -- --
Amortization of deferred
Translation adjustment............ -- -- -- -- -- -- -- --
Net income........................ -- -- -- -- -- -- -- --
------- -------- ------ ------- ------- -------- ----------- -----
BALANCE AT DECEMBER 31, 1999........ -- $ -- 26,468 $ 26 $65,553 $ -- $ (201) $(181)
======= ======== ====== ======= ======= ======== =========== =====

<CAPTION>


Cumulative Retained Total
Translation Earnings Stockholders'
Adjustment (Deficit) Equity
------------ ------------- --------------
<S> <C> <C> <C>
BALANCE AT
DECEMBER 31, 1996................. $ (13) $(26,737) $ 9,098
Issuance of Common
Stock under employee
stock option plan................ -- -- 580
Issuance of Common
Stock in connection
with Public Offering............. -- -- 18,845
Conversion of Preferred
Stock to
Common Stock..................... -- -- --
Change in par value............... -- -- --
Deferred compensation............. -- -- --
Amortization of deferred
compensation..................... -- -- 105
Translation adjustment............ (63) -- (63)
Net income........................ -- 4,762 4,762
----- -------- -------
BALANCE AT
DECEMBER 31, 1997................. (76) (21,975) 33,327
Issuance of Common
Stock under employee
stock option plan, net of
repurchases.............. -- -- 247
Issuance of Common
Stock under employee
stock purchase plan.............. -- -- 627
Exercise of warrants, net......... -- -- 46
Proceeds of stockholder
note repayment................... -- -- 131
Income tax benefit from
employee stock option plan....... -- -- 240
Additional IPO costs.............. -- -- (91)
Amortization of deferred
compensation..................... -- -- 140
Translation adjustment............ 19 -- 19
Net income........................ -- 12,678 12,678
----- -------- -------
BALANCE AT
DECEMBER 31, 1998................. (57) (9,297) 47,364
Issuance of Common
Stock under employee
stock option plan, net of
repurchases.............. -- -- 1,679
Issuance of Common
Stock under employee
stock purchase plan.............. -- -- 1,267
Exercise of warrants, net......... -- -- --
Proceeds of stockholder
note repayment................... -- -- 73
Income tax benefit from
employee stock option plan....... -- -- 5,320
Amortization of deferred
compensation..................... -- -- 140
Translation adjustment............ (72) -- (72)
Net income........................ -- 24,477 24,477
----- -------- -------
BALANCE AT
$(129) $ 15,180 $80,248
DECEMBER 31, 1999................. ===== ======== =======
</TABLE>

The accompanying notes are an integral part of these consolidated financial
statements.

37
POWER INTEGRATIONS, INC.

CONSOLIDATED STATEMENTS OF CASH FLOWS
FOR THE YEARS ENDED DECEMBER 31, 1999, 1998 AND 1997

(In thousands)

<TABLE>
<CAPTION>
1999 1998 1997
--------- --------- ---------
CASH FLOWS FROM OPERATING ACTIVITIES:
<S> <C> <C> <C>
Net income $ 24,477 $ 12,678 $ 4,762
Adjustments to reconcile net income to net cash provided by
operating activities:
Depreciation and amortization.................................................. 3,231 3,034 2,265
Deferred compensation expense.................................................. 140 140 105
Deferred income taxes.......................................................... (3,918) 240 --
Provision for (reduction in) accounts receivable and other allowances.......... (303) 24 984
Change in operating assets and liabilities:
Accounts receivable......................................................... (4,738) 1,579 (4,450)
Inventories................................................................. (2,561) (1,517) (3,390)
Prepaid expenses and other current assets................................... (610) (463) (49)
Accounts payable............................................................ 656 (1,036) 5,427
Accrued liabilities......................................................... 5,716 2,637 1,754
Deferred income on sales to distributors.................................... 800 1,186 646
-------- -------- --------

Net cash provided by operating activities................................ 22,890 18,502 8,054
-------- -------- --------

CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property and equipment............................................ (6,592) (1,956) (1,439)
Purchases of short-term investments............................................ (52,070) (47,904) (13,402)
Proceeds from sales and maturities of short-term investments................... 38,524 31,117 14,357
-------- -------- --------
Net cash used in investing activities.................................... (20,138) (18,743) (484)
-------- -------- --------
CASH FLOWS FROM FINANCING ACTIVITIES:
Net proceeds from issuance of common stock..................................... 2,946 828 19,425
Proceeds from stockholder note repayment....................................... 73 131 --
Principal payments under capitalized lease obligations......................... (2,064) (2,095) (1,724)
Repayment related to note payable to a stockholder............................. -- -- (3,000)
-------- -------- --------
Net cash provided by (used in) financing activities...................... 955 (1,136) 14,701
-------- -------- --------
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS............................. 3,707 (1,377) 22,271
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD................................. 24,176 25,553 3,282
-------- -------- --------
CASH AND CASH EQUIVALENTS AT END OF PERIOD....................................... $ 27,883 $ 24,176 $ 25,553
======== ======== ========
SUPPLEMENTAL DISCLOSURE OF NON-CASH INVESTING AND
FINANCING ACTIVITIES:
Capitalized lease obligations incurred for property and equipment.............. $ 772 $ 1,786 $ 1,630
======== ======== ========
Conversion of preferred stock to common stock.................................. $ -- $ -- $ 35,271
======== ======== ========
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION:
Cash paid for interest......................................................... $ 312 $ 445 $ 832
======== ======== ========
Cash paid for income taxes..................................................... $ 3,208 $ 714 $ 164
======== ======== ========
</TABLE>

The accompanying notes are an integral part of these consolidated financial
statements.



38
POWER INTEGRATIONS, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS

DECEMBER 31, 1999

1. THE COMPANY:

Power Integrations, Inc. (the "Company"), which was incorporated in
California on March 25, 1988 and reincorporated in Delaware in December 1997
(see Note 6), designs, develops, manufactures and markets proprietary, high-
voltage, analog integrated circuits for use in AC to DC power conversion
primarily for the cellular telephone, personal computer and various consumer and
industrial electronics markets.

The Company is subject to a number of risks including, among others, the
volume and timing of orders received by the Company from its customers;
competitive pressures on selling prices; the volume and timing of orders placed
by the Company with its foundries; the availability of raw materials;
fluctuations in manufacturing yields, whether resulting from the transition to
new foundries or from other factors; changes in product mix, including the
impact of new product introductions on existing products; the Company's ability
to develop and bring to market new products and technologies on a timely basis;
the introduction of products and technologies by the Company's competitors;
market acceptance of the Company's and its customers' products; the timing of
investments in research and development and sales and marketing; cyclical
semiconductor industry conditions; fluctuations in exchange rates, particularly
exchange rates between the U.S. dollar and the Japanese yen; and changes in the
international business climate and economic conditions.

All of the wafers are manufactured by two offshore independent foundries.
Although there are a number of other suppliers that could provide similar
services, a change in suppliers could cause a delay in manufacturing and
possible loss of sales, which could adversely affect operating results.

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES:

Principles of Consolidation and Foreign Currency Translation

The consolidated financial statements include the accounts of the Company
and its wholly owned subsidiaries after elimination of intercompany transactions
and balances. The functional currencies of the Company's subsidiaries are the
local currencies. Accordingly, all assets and liabilities are translated into
U.S. dollars at the current exchange rates as of the applicable balance sheet
date. Revenues and expenses are translated at the average exchange rate
prevailing during the period. Cumulative gains and losses from the translation
of the foreign subsidiaries' financial statements have been included in
stockholders' equity.

Cash and Cash Equivalents and Short-Term Investments

The Company considers cash invested in highly liquid financial instruments
with an original maturity of three months or less to be cash equivalents. Cash
investments in highly liquid financial instruments with original maturities
greater than three months but not longer than fifteen months are classified as
short-term investments. As of December 31, 1999 and 1998, the Company's short-
term investments consist of U.S. government backed securities, corporate
commercial paper and other high quality commercial and municipal securities,
which were classified as held-to-maturity and were valued using the amortized
cost method which approximates market.

39
POWER INTEGRATIONS, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(Continued)


The table below summarizes the value of the company's investments by major
security type as of December 31, 1999 and 1998:

<TABLE>
<CAPTION>
(in thousands)
1999 1998
------- -------
<S> <C> <C>
Cash Equivalents:
U.S. corporate securities......................................................... $ 5,488 $15,596
Tax-exempt securities............................................................. 20,500 --
------- -------


Total cash equivalents....................................................... 25,988 15,596
------- -------

Short-term Investments:
U.S. corporate securities......................................................... 17,897 14,881
U.S. government securities........................................................ -- 959
Foreign securities................................................................ 3,079 3,922
Tax-exempt securities............................................................. 11,999 --
------- -------

Total short-term investments................................................. 32,975 19,762
------- -------

Total investment securities.................................................. $58,963 $35,358
======= =======
</TABLE>

Inventories

Inventories (which consist of costs associated with the purchases of wafers
from offshore foundries and of packaged components from several offshore
assembly manufacturers, as well as internal labor and overhead associated with
the testing of both wafers and packaged components) are stated at the lower of
cost (first-in, first-out) or market. Provisions, when required, are made to
reduce excess and obsolete inventories to their estimated net realizable values.
Inventories consist of the following (in thousands):

<TABLE>
<CAPTION>
December 31,
-------------------------
1999 1998
---------- ----------
<S> <C> <C>
Raw materials......................................... $ 4,039 $3,132
Work-in-process....................................... 4,059 2,901
Finished goods........................................ 3,308 2,812
------- ------
$11,406 $8,845
======= ======
</TABLE>

Property and Equipment

Depreciation and amortization of property and equipment are provided using
the straight-line method over the shorter of the estimated useful lives of the
assets over a period of one to four years or over the applicable lease term.

Included in property and equipment are assets acquired under capital lease
obligations with an original cost of approximately $9.0 million and $8.2
million, as of December 31, 1999 and 1998, respectively. Related accumulated
amortization on these leased assets was approximately $5.7 million and $4.7
million, as of December 31, 1999 and 1998, respectively.

40
POWER INTEGRATIONS, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(Continued)

Earnings Per Share

In December 1997, the Company adopted Statement of Financial Accounting
Standards (SFAS) No. 128 "Earnings per Share." SFAS No. 128 requires companies
to compute earnings per share under two different methods (basic and diluted).
Basic earnings per share is calculated by dividing net income by the weighted
average shares of common stock outstanding during the period. Diluted earnings
per share is calculated by dividing net income by the weighted average shares of
outstanding common stock and common stock equivalents during the period. Common
stock equivalents included in the diluted calculation consist of dilutive shares
issuable upon the exercise of outstanding common stock options and warrants
computed using the treasury stock method.

A summary of the earnings per share calculation for each of the three years
ended December 31, 1999, 1998 and 1997 is as follows (in thousands, except per
share amounts):

<TABLE>
<CAPTION>
1999 1998 1997
---- ---- ----
<S> <C> <C> <C>
Basic earnings per share:
Net Income.................................................................. $24,477 $12,678 $ 4,762
======= ======= =======
Weighted average common shares.............................................. 25,958 24,426 3,776
======= ======= =======
Basic earnings per share................................................. $ 0.94 $ 0.52 $ 1.26
======= ======= =======
Diluted earnings per share:
Net Income.................................................................. $24,477 $12,678 $ 4,762
======= ======= =======
Weighted average common shares.............................................. 25,958 24,426 3,776
Weighted average common share equivalents:
Preferred stock.......................................................... -- -- 14,078
Options.................................................................. 2,170 1,446 578
Employee stock purchase plan............................................. 69 10 --
Warrants................................................................. -- 570 246
------- ------- -------
Diluted weighted average common shares...................................... 28,197 26,452 18,678
======= ======= =======
Diluted earnings per share............................................... $ 0.87 $ 0.48 $ 0.25
======= ======= =======
</TABLE>

Comprehensive Income

In June 1997, the Financial Accounting Standards Board issued SFAS No. 130,
"Reporting Comprehensive Income," which establishes standards for reporting and
presentation of comprehensive income. SFAS No. 130, which was adopted by the
Company in the first quarter of 1998, requires companies to report a new measure
of income. "Comprehensive Income" is to include foreign currency translation
gains and losses and other unrealized gains and losses that have historically
been excluded from net income and reflected instead in equity. SFAS No. 130 did
not have a material impact on the Company's financial statements.

Segment Reporting

During 1998, the Company adopted SFAS No. 131, "Disclosures About Segments
of an Enterprise and Related Information." SFAS No. 131 requires a new basis of
determining reportable business segments, i.e., the management approach. This
approach requires that business segment information used by management to assess
performance and manage company resources be the source for information
disclosure. On this basis, the Company is organized and operates as one business
segment, the design, development, manufacture and marketing of proprietary,
high-voltage, analog integrated circuits for use primarily in the AC to DC power
conversion markets.

41
POWER INTEGRATIONS, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(Continued)

New Accounting Standards

In June 1998, the Financial Accounting Standards Board issued SFAS No. 133,
"Accounting for Derivative Instruments and Hedging Activities." SFAS No. 133
establishes accounting and reporting standards for derivative instruments,
hedging activities, and exposure definition. SFAS No. 133 requires companies to
recognize all derivatives as either assets or liabilities in the statement of
financial position and measure those instruments at fair value. SFAS No. 133 is
effective for all fiscal quarters of fiscal years beginning after June 15, 2000.
The Company does not expect the adoption of SFAS No. 133 to have a material
impact on its financial statements.

In December 1999, the Securities and Exchange Commission issued Staff
Accounting Bulletin No. 101 ("SAB 101"), "Revenue Recognition in Financial
Statements." SAB 101 provides guidance on applying generally accepted accounting
principles to revenue recognition issues in financial statements. The Company
will adopt SAB 101 as required in the first quarter of 2000 and is evaluating
the effect that such adoption may have on its consolidated results of operations
and financial position.

Revenue Recognition, Significant Customers

Product revenues consist of sales to OEMs and merchant power supply
manufacturers and to distributors. Revenues from product sales to OEM and
merchant power supply manufacturers are recognized upon shipment. The Company
provides for estimated sales returns and allowances related to such sales at the
time of shipment. During 1999, 1998 and 1997, sales to distributors of the
Company's products accounted for approximately 40%, 48% and 45% of net revenues,
respectively. Sales to distributors are made under terms allowing certain rights
of return and protection against subsequent price declines of the Company's
products held by the distributors. Pursuant to the Company's distributor
agreements, the Company protects its distributors' exposure related to the
impact of price reductions as well as products at distributors that are slow
moving or have been discontinued. These agreements, which may be canceled by
either party on a specified notice, generally contain a provision for the return
of the Company's product in the event the agreement with the distributor is
terminated. Accordingly, the Company defers recognition of revenue and the
proportionate costs of revenues derived from sales to distributors until such
distributors resell the Company's products to their customers. The margin
deferred as a result of this policy is reflected as "deferred income on sales to
distributors" in the accompanying consolidated balance sheets.

The Company has entered into a separate wafer supply and technology license
agreement with an unaffiliated wafer foundry. The wafer supply agreement, which
expires in June 2000, is renewable. In connection with the technology license
agreement, the Company is entitled to receive a royalty on sales of products by
the foundry, which incorporates the Company's technology into its own products.
For the years ended December 31, 1999, 1998 and 1997, revenue recognized under
this agreement was approximately $1.4 million, $1.8 million and $1.2 million,
respectively.

42
POWER INTEGRATIONS, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(Continued)

The Company's end user base is highly concentrated and a relatively small
number of OEMs, directly or indirectly through merchant power supply
manufacturers, accounted for a significant portion of the Company's revenue. For
the years ended December 31, 1999, 1998 and 1997, ten customers accounted for
approximately 68%, 67% and 67% of net revenues, respectively.

The following customers accounted for more than 10% of total net revenues:

<TABLE>
<CAPTION>
Year Ended December 31,
------------------------------------------
Customer 1999 1998 1997
-------- ---------- ---------- ----------
<S> <C> <C> <C>
A...................................... 16% 22% 21%
B...................................... * * 15%
C...................................... 11% 13% *
</TABLE>

- ----------------
* less than 10% or no sales to the customer


Export Sales

The Company markets its products in North America and in foreign countries
through its sales personnel and a worldwide network of independent sales
representatives and distributors. Export sales, which consist of domestic sales
to customers in foreign countries are comprised of the following:

<TABLE>
<CAPTION>
Year Ended December 31,
------------------------------------------
1999 1998 1997
---------- ---------- ----------
<S> <C> <C> <C>
Hong Kong/China....................................... 20% 26% 25%
Taiwan................................................ 19% 26% 28%
Western Europe........................................ 16% 15% 12%
Korea................................................. 13% 7% 5%
Japan................................................. 2% 3% 5%
Other................................................. 8% 6% 6%
---- ---- ----
Total export sales.................................. 78% 83% 81%
==== ==== ====
</TABLE>

Product Sales

Sales of TOPSwitch products accounted for 97%, 95% and 93% of total net
revenues in 1999, 1998 and 1997, respectively. TOPSwitch products include
TOPSwitch, TOPSwitch II and TinySwitch.

Foreign Currency Risk

The Company maintains a Japanese yen bank account with a U.S. bank for
payments to suppliers and for cash receipts from Japanese suppliers and
customers denominated in yen. For the years ended December 31, 1999 and 1998,
the Company realized foreign exchange transaction gains of approximately
$123,000 and $35,000, respectively. For the year ended December 31, 1997, the
Company realized a foreign exchange transaction loss of approximately $86,000.
These amounts are included in "other income (expense)," in the accompanying
consolidated statements of operations.

Estimates

The preparation of financial statements in conformity with generally
accepted accounting principles requires management to make estimates and
assumptions that affect the reported amounts of assets and liabilities and
disclosures of contingent assets and liabilities at the date of the financial
statements and the reported amounts of revenues and expenses during the
reporting period. Actual results could differ from those estimates.

43
POWER INTEGRATIONS, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(Continued)

Concentration of Credit Risk

Financial instruments that potentially subject the Company to
concentrations of credit risk consist principally of cash investments and trade
receivables. The Company has cash investment policies that limit cash
investments to short-term, low risk investments. With respect to trade
receivables, the Company performs ongoing credit evaluations of its customers'
financial condition and requires letters of credit whenever deemed necessary.
Additionally, the Company establishes an allowance for doubtful accounts based
upon factors surrounding the credit risk of specific customers, historical
trends related to past losses and other relevant information. As of December 31,
1999 and 1998, approximately 73% and 67% of accounts receivable, respectively,
were concentrated with ten customers.

3. BANK LINE OF CREDIT:

The Company entered into a $10.0 million revolving line of credit agreement
with a bank in October 1998. Advances under the agreement bear interest at a
fixed rate of the bank's LIBOR rate plus 1.5% per annum or at the bank's
variable interest rate. The Company has the option to choose between the two
rates. The agreement covers advances for commercial letters of credit and
standby letters of credit, used primarily for the shipment of wafers from our
wafer supply manufacturers to us, provided that at no time will the aggregate
sum of all advances exceed $10.0 million. As of December 31, 1999, there were
outstanding letters of credit totaling 96,587,000 Japanese yen (approximately
$964,000). As of December 31, 1998, there were outstanding letters of credit
totaling 382,478,000 Japanese yen (approximately $3.4 million). The agreement,
which expires on November 30, 2000, restricts the Company from entering into
certain transactions and contains certain financial covenants.

4. COMMITMENTS:

The Company leases its facilities under noncancellable operating leases,
which expire at various dates through October 2010. The lease for the Company's
main corporate facility in Sunnyvale, California expires in October 2003 and
contains a conditional five-year option at fair market value to the year 2008.
The Company also has an additional facility, which is leased through June 2003.
On December 29, 1999, the Company entered into a lease for a new facility, which
will become available in mid 2000, at which time the Company plans to relocate
its main operations to that site. The lease on the new facility has a term of 10
years, expiring in May 2010 with two conditional five-year options, which if
exercised would extend the lease to May 2020. Rent expense under all operating
leases was approximately $1.1 million, $500,000 and $291,000 in 1999, 1998 and
1997, respectively.

A significant portion of the Company's machinery and equipment is leased
under agreements accounted for as capital leases. The Company leased
approximately $772,000 and $1.8 million of equipment during 1999 and 1998,
respectively, under various capital leasing arrangements. In 1998, the Company
entered into a new capital lease line of credit agreement, which allowed for
combined borrowings of up to $4.4 million to finance the acquisition of property
and equipment. The capital leasing agreement expired on June 30, 1999.

44
POWER INTEGRATIONS, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(Continued)

Future minimum lease payments under all noncancellable operating and
capital lease agreements as of December 31, 1999 are as follows (dollars in
thousands):

<TABLE>
<CAPTION>
Fiscal Year Operating Capital
----------- --------- -------
<S> <C> <C>
2000 $ 2,185 $ 1,373
2001 3,157 758
2002 3,066 463
2003 2,859 241
2004 2,126 42
Thereafter 12,997 --
------- -------

Total minimum lease payments.................................................. $26,390 2,877
=======
Less: Amounts representing interest on capital leases (4.4% to 14.9%)......... (256)
-------
2,621
Less: Current portion.......................................................... (1,228)
-------
Long-term portion.............................................................. $ 1,393
=======
</TABLE>

5. PREFERRED STOCK PURCHASE RIGHTS PLAN:

In February 1999, the Company adopted a Preferred Stock Purchase Rights
Plan (the "Plan") designed to enable all stockholders to realize the full value
of their investment and to provide for fair and equal treatment for all
stockholders in the event that an unsolicited attempt is made to acquire the
Company. Under the Plan, stockholders received one Right to purchase one one-
thousandth of a share of a new series of Preferred Stock for each outstanding
share of Common Stock held of record at the close of business on March 12, 1999
at $150.00 per Right, when someone acquires 15 percent or more of the Company's
Common Stock or announces a tender offer which could result in such person
owning 15 percent or more of the Common Stock. Each one one-thousandth of a
share of the new Preferred Stock has terms designed to make it substantially the
economic equivalent of one share of Common Stock. Prior to someone acquiring 15
percent, the Rights can be redeemed for $.001 each by action of the Board of
Directors. Under certain circumstances, if someone acquires 15 percent or more
of the Common Stock, the Rights permit the stockholders other than the acquiror
to purchase the Company's Common Stock having a market value of twice the
exercise price of the Rights, in lieu of the Preferred Stock. Alternatively,
when the Rights become exercisable, the Board of Directors may authorize the
issuance of one share of Common Stock in exchange for each Right that is then
exercisable. In addition, in the event of certain business combinations, the
Rights permit the purchase of the Common Stock of an acquiror at a 50 percent
discount. Rights held by the acquiror will become null and void in both cases.
The Rights expire on February 23, 2009.

6. STOCKHOLDERS' EQUITY:

Preferred Stock

With the closing of the Company's IPO in December 1997, all of the
outstanding convertible preferred stock automatically converted into 14,895,116
shares of common stock. Upon conversion of the outstanding preferred stock to
common stock, such preferred stock was retired. The Company is authorized to
issue 3,000,000 shares of new $0.001 par value preferred stock, of which none
was outstanding as of December 31, 1999.

45
POWER INTEGRATIONS, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(Continued)

Common Stock

As of December 31, 1999, the Company was authorized to issue 40,000,000
shares of $0.001 par value common stock. On October 25, 1999, the Company's
Board of Directors approved a two-for-one split of the Company's common stock,
in the form of a 100 percent stock dividend, that was applicable to stockholders
of record at the close of business on November 8, 1999, and effective on
November 22, 1999. All references to share and per-share data for all periods
presented have been adjusted to give effect to this two-for-one stock split.

1988 Stock Option Plan

In June 1988, the board of directors approved the 1988 Stock Option Plan
(the "1988 Plan"), whereby the board of directors may grant options to key
employees, directors and consultants to purchase the Company's common stock at
exercise prices of not less than 85% of the fair value of the shares at the date
of grant. Options expire ten years after the date of grant (five years if the
option is granted to a ten percent owner optionee) and generally vest over 50
months. Options granted under the 1988 Plan will remain outstanding in
accordance with their terms, but effective July 1997, the board of directors had
determined that no further options would be granted under the 1988 Plan.

1997 Stock Option Plan

In June 1997, the board of directors approved the 1997 Stock Option Plan
(the "1997 Plan"), whereby the board of directors may grant options to key
employees, directors and consultants to purchase the Company's common stock at
exercise prices of not less than 85% of the fair value of the shares at the date
of grant. As of December 31, 1999, the 1997 Plan's maximum share reserve is
5,514,160 shares, which is comprised of the sum of (i) 2,571,196 shares (new
shares allocated to the 1997 Plan) and (ii) 2,942,964 shares granted pursuant to
the 1988 Plan (the "1988 Plan Options"). The number of shares available for
issuance under the 1997 Plan, at any time, is reduced by the number of shares
remaining subject to the 1988 Plan Options. Options expire ten years after the
date of grant (five years if the option is granted to a ten percent owner
optionee) and generally vest over 48 months.

1997 Outside Directors Stock Option Plan

In September 1997, the board of directors approved an Outside Director
Stock Option Plan (the "Directors Plan"). A total of 400,000 shares of common
stock have been reserved for issuance under the Directors Plan. The Directors
Plan provides for the grant of nonstatutory stock options to nonemployee
directors of the Company. The Directors Plan is designed to work automatically
without administration; however, to the extent administration is necessary, it
will be performed by the board of directors. The Directors Plan provides that
each current and future nonemployee director of the Company will be granted an
option to purchase 30,000 shares of common stock on the effective date or the
date on which the optionee first becomes a nonemployee director of the Company
after the effective date as the case may be (the "Initial Grant"). Thereafter,
each nonemployee director who has served on the board of directors continuously
for 6 months will be granted an additional option to purchase 10,000 shares of
common stock (an "Annual Grant"). Subject to an optionee's continuous service
with the Company, approximately 1/3/rd/ of an Initial Grant will become
exercisable one year after the date of grant and 1/36/th/ of the Initial Grant
will become exercisable monthly thereafter. Each Annual Grant will become
exercisable in twelve monthly installments beginning in the 25th month after the
date of grant, subject to the optionee's continuous service. The exercise price
per share of all options granted under the Directors Plan will equal the fair
market value of a share of common stock on the date of grant. Options granted
under the Directors Plan have a term of ten years and are non-transferable. In
the event of certain changes in control of the Company, options outstanding
under the Directors Plan will become immediately exercisable and vested in full.

46
POWER INTEGRATIONS, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(Continued)

1998 Nonstatutory Stock Option Plan

In July 1998, the board of directors approved the 1998 Nonstatutory Stock
Option Plan (the "1998 Plan"), whereby the board of directors may grant
nonstatutory options to employees and consultants to purchase the Company's
common stock at exercise prices of not less than 85% of the fair value of the
shares at the date of grant. As of December 31, 1999, the maximum share reserve
under this plan was 1,000,000 shares. Options expire ten years after the date of
grant (five years if the option is granted to a ten percent owner optionee) and
generally vest over 48 months.

The following table summarizes option activity under the Company's option
plans:

(prices are weighted average prices)

<TABLE>
<CAPTION>
Year Ended December 31,
-----------------------
1999 1998 1997
---- ---- ----

Shares Price Shares Price Shares Price
------ ----- ------ ----- ------ -----
<S> <C> <C> <C> <C> <C> <C>
Options outstanding,
Beginning of year........... 2,666,422 $ 3.11 1,749,512 $1.38 2,592,852 $0.40
Granted................... 1,704,875 $18.06 1,317,300 $5.08 1,324,864 $1.35
Exercised................. (769,316) $ 2.15 (275,476) $0.89 (2,099,204) $0.28
Cancelled................. (272,906) $11.23 (124,914) $3.28 (69,000) $0.71
--------- --------- ----------
Options outstanding,
end of year................. 3,329,075 $10.40 2,666,422 $3.11 1,749,512 $1.38
========= ========= ==========

Exercisable, end of year........ 723,496 $ 3.71 727,348 $1.11 475,258 $0.49
========= ========= ==========
</TABLE>

Options issued under the 1988, 1997 and 1998 plans may be exercised at any
time prior to their expiration. Options issued under the Directors Plan are
exercisable upon vesting. In addition, the Company has the right, upon
termination of an optionholder's employment or service with the Company, at its
discretion, to repurchase any unvested shares issued under the 1988, 1997 and
1998 plans at the original purchase price. Under the terms of the option plans,
an option holder may not sell shares obtained upon the exercise of an option
until the option has vested as to those shares. As of December 31, 1999, an
aggregate of 148,240 shares of common stock issued under the 1988, 1997 and 1998
plans are subject to repurchase by the Company at $0.68 to $0.85 per share and a
weighted average repurchase price of $0.81 per share.

The Company accounts for its Plans under APB Opinion No. 25, "Accounting
for Stock Issued to Employees." Had compensation expense for the Plans been
determined under a fair value method consistent with SFAS No. 123, "Accounting
for Stock Based Compensation," the Company's net income would have been
decreased to the following pro forma amounts (in thousands, except per share
information):

<TABLE>
<CAPTION>
Year Ended December 31,
-----------------------
1999 1998 1997
---- ---- ----
<S> <C> <C> <C>
Net income:
As reported................................................................... $24,477 $12,678 $4,762
Pro forma..................................................................... $18,891 $11,599 $4,427
Basic earnings per share:
As reported................................................................... $ 0.94 $ 0.52 $ 1.26
Pro forma..................................................................... $ 0.73 $ 0.47 $ 1.17
Diluted earnings per share:
As reported................................................................... $ 0.87 $ 0.48 $ 0.25
Pro forma..................................................................... $ 0.67 $ 0.44 $ 0.24
</TABLE>

47
POWER INTEGRATIONS, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(Continued)

The weighted-average grant date fair value of options granted during fiscal
years 1999, 1998 and 1997 was $11.85, $10.15 and $1.68, respectively. The fair
value of each option grant is estimated on the date of grant using the Black-
Scholes option pricing model with the following weighted average assumptions
used for grants in 1999, 1998 and 1997: risk-free interest rates of 5.625, 5.25
and 6.2 percent, respectively; expected dividend yields of zero percent;
expected lives of 1.5 years for 1999 and 1998, and 4 years for 1997; expected
volatility of 84%, 73% and 70% for 1999, 1998 and 1997, respectively.

The following table summarizes the stock options outstanding at December
31, 1999:

<TABLE>
<CAPTION>
Options Outstanding Options Exercisable
- ------------------------------------------------------------------------- ----------------------------------------
Weighted Weighted Weighted
Average Average Average
Exercise Number Remaining Exercise Number Exercise
Price Outstanding Life Price Outstanding Price
- -------------------- --------------- --------------- ----------------- ------------------ ------------------
<S> <C> <C> <C> <C> <C>
$ 0.26--$ 4.00 595,536 6.75 $ 1.08 410,319 $ 0.98
$ 4.25--$ 4.38 916,336 8.50 $ 4.37 144,699 $ 4.37
$ 4.42--$ 11.06 301,405 8.28 $ 8.94 98,209 $ 5.60
$ 12.00--$ 29.19 1,363,623 9.31 $14.22 69,269 $15.43
$ 30.69--$ 51.50 152,175 9.79 $26.84 1,000 $33.20
--------- -------
$ 0.26--$ 51.50 3,329,075 8.56 $10.40 723,496 $ 3.71
========= =======
</TABLE>


1997 Employee Stock Purchase Plan

Under the 1997 Employee Stock Purchase Plan (the "Purchase Plan"), 1,000,000
shares of common stock are reserved for issuance to eligible employees. The
Purchase Plan permits employees to purchase common stock through payroll
deductions, which may not exceed 15 percent of an employee's compensation, at
85% of the lower of the fair market value of the Company's common stock on the
first or the last day of each offering period. As of December 31, 1999, 534,770
shares had been purchased and 465,230 shares were reserved for future issuance
under the Purchase Plan.

Stockholder Notes Receivable

In July 1997, in connection with the purchase of common stock upon exercise of
stock options granted to certain officers and employees of the Company, the
Company loaned to these officers and employees an aggregate of $405,000, at an
interest rate of 6.65% pursuant to Promissory Note and Pledge Agreements. These
loans, which are secured by 238,231 shares of common stock, are full recourse
notes, and are due in full without regard to the value of the Company's common
stock in July 2002, or at the Company's option upon (i) termination of
employment with the Company, (ii) a default in the payment of any installment or
principal and/or interest when due, (iii) a sale of the pledged stock or (iv)
acceleration being reasonably necessary for the Company to comply with any
regulations promulgated by the Board of Governors of the Federal Reserve System
affecting the extension of credit in connection with the Company's securities.
As of December 31, 1999, the unpaid principal portion of these loans was
$201,000.

Deferred Compensation

In connection with the issuance of stock options to employees and
consultants prior to December 1997, the Company recorded deferred compensation
in the aggregate amount of approximately $566,000, representing the difference
between the fair market value of the Company's common stock and the exercise
price of the stock

48
POWER INTEGRATIONS, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(Continued)

options at the date of grant. The Company is amortizing the deferred
compensation expense over the shorter of the period in which the employee,
director or consultant provides services or the applicable vesting period, which
is typically over 48 months. Amortization expense was $140,000 in each of the
years ended December 31, 1999 and 1998 and $105,000 in 1997. Compensation
expense is decreased in the period of forfeiture for any accrued, but unvested
compensation arising from the early termination of an option holder's services.
No compensation expense related to any other periods presented has been
recorded.

Warrants

In connection with the issuance of Series E Preferred Stock in 1994, the
Company issued warrants for the purchase of Series E Preferred Stock, which upon
the completion of the IPO and the reincorporation in Delaware, were
automatically converted to purchase 20,728 shares of common stock at $5.74 per
share. These warrants were exercised in 1998.

In connection with an equipment lease agreement entered into during 1993
with a leasing company, the Company issued a warrant for the purchase of
preferred stock. Upon the completion of the IPO and the reincorporation in
Delaware, the warrant was automatically converted to purchase 16,303 shares of
common stock at $3.68 per share. This same warrant provides for the purchase of
additional preferred stock, which, upon the completion of the IPO and the
reincorporation in Delaware, was automatically converted to purchase 12,551
shares of common stock at $4.78 per share. This warrant was exercised in 1999.
The Company leased additional equipment during 1994 from the same company and,
as part of this lease, the Company issued a warrant for the purchase of
preferred stock. Upon the completion of the IPO and the reincorporation in
Delaware, the warrant automatically converted into a warrant to purchase 12,551
shares of common stock at $4.78 per share. This warrant was exercised in 1999.
In 1995, the Company leased additional equipment from the same company and
issued a warrant to purchase preferred stock, which upon the completion of the
IPO and the reincorporation in Delaware, automatically converted into a warrant
to purchase 24,509 shares of common stock at $3.67 per share. This warrant was
exercised in 1999.

In connection with an equipment leasing agreement entered into during 1995
with a leasing company, the Company issued a warrant to purchase 41,165 shares
of the Company's common stock at $6.34 per share. This warrant was exercised in
1998.

In connection with obtaining the revolving line of credit agreement with a
bank in 1995, the Company issued the bank warrants to purchase preferred stock.
Upon the completion of the IPO and the reincorporation in Delaware, the warrants
were automatically converted to purchase 146,786 shares of common stock at $3.67
per share. These warrants were exercised in 1998. In connection with the renewal
of the line of credit agreement in 1996, the Company issued the bank a warrant
to purchase 23,149 shares of common stock at $6.34 per share. This warrant was
exercised in 1998.

In connection with the issuance of a note payable to a stockholder in 1996,
the Company issued a warrant to purchase 176,470 shares of the Company's common
stock at $1.36 per share. This warrant was exercised in 1999.

Shares Reserved

As of December 31, 1999, the Company had 4,256,118 shares of common stock
reserved for future issuance under Stock Option and Stock Purchase Plans.

49
POWER INTEGRATIONS, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(Continued)

7. INCOME TAXES:

The Company accounts for income taxes under SFAS No. 109 "Accounting for
Income Taxes." SFAS No. 109 provides for a liability approach to accounting for
income taxes under which deferred income taxes are provided based upon enacted
tax laws and rates applicable to the periods in which taxes become payable.

The components of the provision for income taxes are as follows (in
thousands):

<TABLE>
<CAPTION>
Year Ended December 31,
-----------------------
1999 1998 1997
---- ---- ----
<S> <C> <C> <C>
Current provision:
Federal......................................................... $ 7,621 $ 1,886 $ 262
State........................................................... 616 694 55
Foreign......................................................... 15 20 16
------- ------- -------
8,252 2,600 333
------- ------- -------
Deferred provision (benefit):
Federal......................................................... 1,125 4,136 1,946
State........................................................... 99 (103) (404)
Foreign......................................................... -- -- --
------- ------- -------
1,224 4,033 1,542
------- ------- -------

Net decrease in valuation allowance................................ (5,142) (4,033) (1,345)
------- ------- -------
$ 4,334 $ 2,600 $ 530
======= ======= =======
</TABLE>

The provision for income taxes differs from the amount, which would result
by applying the applicable Federal income tax rate to income before provision
for income taxes as follows:

<TABLE>
<CAPTION>
Year Ended December 31,
-----------------------
1999 1998 1997
---- ---- ----
<S> <C> <C> <C>
Provision computed at Federal statutory rate......................... 35.0% 35.0% 34.0%
State tax provision, net of Federal benefit.......................... 3.1 3.1 3.0
Foreign tax.......................................................... -- 0.1 0.3
Change in valuation allowance........................................ (17.9) (23.0) (25.4)
Research and development credits..................................... (3.4) (3.0) (6.2)
Foreign sales corporation............................................ (2.5) -- --
Non deductible expenses and other.................................... 0.7 4.8 4.3
----- ----- -----
15.0% 17.0% 10.0%
===== ===== =====
</TABLE>

The components of the net deferred income tax asset were as follows (in
thousands):

<TABLE>
<CAPTION>
December 31,
------------
1999 1998
---- ----
<S> <C> <C>
Tax credit carryforwards.......................................................... $ 494 $ 1,128
Inventory reserves................................................................ 1,896 2,283
Accounts receivable allowances.................................................... 377 527
Accrued vacation.................................................................. 121 132
Other cumulative temporary differences............................................ 1,030 1,072
------ -------
3,918 5,142
Valuation allowance............................................................... -- (5,142)
------ -------
$3,918 $ --
====== =======
</TABLE>


50
POWER INTEGRATIONS, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(Continued)

The deferred tax asset of $3.9 million at December 31, 1999 is included in
prepaid expenses and other current assets in the accompanying consolidated
balance sheet. Realization of the deferred tax asset is dependent on generating
sufficient future taxable income. Although realization is not assured,
management believes it is more likely than not that all of the deferred tax
asset will be realized.

As of December 31, 1999, the Company had research and development tax
credit carryforwards of approximately $494,000. These carryforwards expire in
various periods from 2010 to 2019. The United States Tax Reform Act of 1986
contains provisions that limit research and development credits available to be
used in any given year upon the occurrence of certain events.

8. LEGAL PROCEEDINGS:

In July 1998, the Company filed a complaint for patent infringement in the
U.S. District Court, Northern District of California, against its largest end
user, Motorola. In August 1998, the Company voluntarily dismissed the complaint,
and filed a new complaint in the U.S. District Court, District of Delaware,
alleging that Motorola has infringed and continues to infringe two of the
Company's circuit patents. In October 1998, Motorola asserted various
counterclaims against the Company, alleging that the Company is infringing
certain of Motorola's patents.

Trial of this action was held in October 1999. On October 15, 1999, the
jury returned a unanimous verdict in favor of the Company. The jury determined
that Motorola had willfully infringed one of the Company's patents and awarded
the Company $32.3 million in compensatory damages. The jury also found that the
Company had not infringed any of the asserted Motorola patents and that two of
the Motorola patents were invalid. In March 2000, the Company and Motorola
entered into a settlement agreement. Pursuant to the settlement agreement, the
Court has issued a permanent injunction prohibiting Motorola from selling the
ICs that were the subject of the lawsuit. Additionally the Company will not
collect the money judgment from Motorola and will continue as a preferred
supplier of high-voltage power conversion ICs for cellular phone chargers that
Motorola manufactures. The companies will work more closely together to develop
future generations of cellular phone chargers for Motorola.

51
SIGNATURES

Pursuant to the requirements of Section 13 or 15(d) of the Securities
Exchange Act of 1934, the registrant has duly caused this Report to be signed on
its behalf by the undersigned, thereunto duly authorized.


POWER INTEGRATIONS, INC.


/s/ ROBERT G. STAPLES
Dated: March 28, 2000 By: --------------------------------
Robert G. Staples
Chief Financial Officer

52
POWER OF ATTORNEY

KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature
appears below constitutes and appoints Howard F. Earhart and Robert G. Staples
his true and lawful attorney-in-fact and agent, with full power of substitution
and, for him and in his name, place and stead, in any and all capacities to sign
any and all amendments to this Report on Form 10-K, and to file the same, with
all exhibits thereto and other documents in connection therewith, with the
Securities and Exchange Commission, granting unto said attorney-in-fact and
agent full power and authority to do and perform each and every act and thing
requisite and necessary to be done in connection therewith, as fully to all
intents and purposes as he might or could do in person, hereby ratifying and
confirming all that said attorney-in-fact and agent, or his substitute or
substitutes, may lawfully do or cause to be done by virtue hereof.

PURSUANT TO THE REQUIREMENTS OF THE SECURITIES EXCHANGE ACT OF 1934, THIS REPORT
HAS BEEN SIGNED BY THE FOLLOWING PERSONS ON BEHALF OF THE REGISTRANT AND IN THE
CAPACITIES AND ON THE DATES INDICATED.

/s/ HOWARD F. EARHART
Dated: March 28, 2000 By: -----------------------------
Howard F. Earhart
President, Chief Executive Officer
and Chairman of the Board
(Principal Executive Officer)

/s/ ROBERT G. STAPLES
Dated: March 28, 2000 By: -----------------------------
Robert G. Staples
Chief Financial Officer
(Principal Financial and Principal
Accounting Officer)

/s/ ALAN D. BICKELL
Dated: March 28, 2000 By: -----------------------------
Alan D. Bickell
Director

Dated: March 28, 2000 By: /s/ NICHOLAS E. BRATHWAITE
-----------------------------
Nicholas E. Brathwaite
Director

By: /s/ R. SCOTT BROWN
Dated: March 28, 2000 -----------------------------
R. Scott Brown
Director

By: /s/ E. FLOYD KVAMME
Dated: March 28, 2000 ------------------------------
E. Floyd Kvamme
Director

By: /s/ STEVEN J. SHARP
Dated: March 28, 2000 ------------------------------
Steven J. Sharp
Director

53
POWER INTEGRATIONS, INC

EXHIBITS
TO
FORM 10-K ANNUAL REPORT

For the Year Ended
December 31, 1999


EXHIBIT NUMBER DESCRIPTION
- -------------- -----------

3.1*** Restated Certificate of Incorporation (we also filed in our
Current Report on Form 8-K filed with the SEC on March 12,
1999, a Certificate of Designation which amends this
Restated Certificate).

3.2*++ By-Laws, as amended February 24, 1999.

4.1* Fifth Amended and Restated Rights Agreement dated April 27,
1995, as amended, by and among us and certain of our
investors.

4.2* Investors' Rights Agreement dated as of May 22, 1996 between
us and Hambrecht & Quist Transition Capital, LLC.

10.1* Form of Indemnification Agreement for directors and
officers.

10.2* 1988 Stock Option Plan and forms of agreements thereunder.

10.3* 1997 Stock Option Plan and forms of agreements thereunder.

10.4* 1997 Outside Directors Stock Option Plan and forms of
agreements thereunder.

10.5* 1997 Employee Stock Purchase Plan and forms of agreements
thereunder.

10.6* Amended Technology License Agreement dated as of June 29,
1995, as amended on April 1, 1997 between us and Matsushita.

10.7* Amended Wafer Foundry Agreement dated as of June 29, 1997,
between us and Matsushita.

10.9* Master Equipment Lease Agreement dated as of February 11,
1997 among us and Finova Technology Finance, Inc.

10.10* Master Lease Agreement dated as of September 3, 1996 between
us and Leasing Technologies International, Inc.

10.11* Master Equipment Lease Agreement dated as of November 17,
1995 between us and Lighthouse Capital Partners, L.P.

10.12* Master Equipment Lease Agreement dated as of December 29,
1993, as amended, between us and MMC/GATX Partnership No. 1.
10.14*          Founder Stock Purchase Agreement between us and Steven J.
Sharp dated as of April 13, 1988.

10.15* Founder Stock Purchase Agreement between us and Klas H.
Eklund dated as of April 13, 1988.

10.16* Founder Stock Purchase Agreement between us and Arthur E.
Fury dated as of April 13, 1988.

10.18** Industrial Building Lease between us and Mathilda
Development, a California limited partnership, dated as of
June 3, 1998.

10.21+ Wafer Supply Agreement between us and OKI, dated as of
October 1, 1998.

10.22+ Master Equipment Lease Agreement between us and Metlife
Capital Limited Partnership, dated as of July 31, 1998.

10.23*** Loan Agreement between us and Union Bank of California,
N.A., dated as of October 16, 1998.

10.24+++ Amendment Number One, dated as of February 26, 1999, to the
Wafer Supply Agreement between us and OKI, dated as of
October 1, 1998.

10.25**** Sublease between us and Atweb, dated as of July 1, 1999.

10.26 Lease agreement dated as of December 29, 1999 between us and
Lincoln - RECP Hellyer OPCO, LLC, a Delaware limited
liability company.


21.1* List of subsidiaries.

23.1 Consent of Independent Public Accountants.

24.1 Power of Attorney (See signature page).

27.1 Financial Data Schedule.

_________________
* As filed with the SEC in our Registration Statement on Form S-1 on
September 11, 1997.

** As filed with the SEC in our quarterly report on Form 10-Q on August 12,
1998.

*** As filed with the SEC in our annual report on Form 10-K on March 16, 1999.

**** As filed with the SEC in our quarterly report on Form 10-Q on November 9,
1999.

+ As filed with the SEC in our quarterly report on Form 10-Q on November 10,
1998.

++ We filed an amendment to the Bylaws with the SEC in our Current Report on
Form 8-K on March 12, 1999.

+++ As filed with the SEC in our quarterly report on Form 10-Q on May 10,
1999.