Document ID: s3://data.kl3m.ai/documents/govinfo/USCOURTS/USCOURTS-ca13-15-01329/USCOURTS-ca13-15-01329-0/pdf.json

Parties Involved:
Fairchild (Taiwan) Corporation
Appellant
Fairchild Semiconductor Corporation
Appellant
Fairchild Semiconductor International, Inc.
Appellant
Power Integrations, Inc.
Cross-Appellant

Document Text:

United States Court of Appeals

for the Federal Circuit ______________________ 

POWER INTEGRATIONS, INC.,

Plaintiff-Cross-Appellant

v.

FAIRCHILD SEMICONDUCTOR 

INTERNATIONAL, INC., FAIRCHILD 

SEMICONDUCTOR CORPORATION, 

FAIRCHILD (TAIWAN) CORPORATION,

Defendants-Appellants

______________________ 

2015-1329, 2015-1388

______________________ 

Appeals from the United States District Court for the 

District of Delaware in No. 1:08-cv-00309-LPS, Chief 

Judge Leonard P. Stark.

______________________ 

Decided: December 12, 2016 

______________________ 

FRANK E. SCHERKENBACH, Fish & Richardson, P.C., 

Boston, MA, argued for plaintiff-cross-appellant. Also 

represented by CRAIG E. COUNTRYMAN, San Diego, CA; 

MICHAEL R. HEADLEY, HOWARD G. POLLACK, Redwood 

City, CA. 

BLAIR M. JACOBS, Paul Hastings LLP, Washington, 

DC, argued for defendants-appellants. Also represented 

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2 POWER INTEGRATIONS v. FAIRCHILD SEMICONDUCTOR

by STEPHEN B. KINNAIRD, CHRISTINA A. ONDRICK, PATRICK 

J. STAFFORD.

______________________ 

Before PROST, Chief Judge, SCHALL, and CHEN, Circuit 

Judges.

CHEN, Circuit Judge.

This appeal follows a ten-day jury trial in the District 

of Delaware that resulted in verdicts that (1) Power 

Integrations Inc.’s U.S. Patent Nos. 7,110,270 and 

7,834,605 were neither anticipated nor obvious and were

not directly or indirectly infringed by Fairchild Semiconductor International, Inc., Fairchild Semiconductor Corporation, and Fairchild (Taiwan) Corporation (collectively, 

Fairchild); (2) Power Integrations’ U.S. Patent Nos. 

6,107,851 and 6,249,876 were not anticipated and were 

directly and indirectly infringed by Fairchild; 

(3) Fairchild’s U.S. Patent No. 7,259,972 was not obvious,

was infringed by Power Integrations under the doctrine of 

equivalents, but was not literally infringed or indirectly 

infringed by Power Integrations; and (4) Fairchild’s U.S. 

Patent No. 7,352,595 was not anticipated and was not 

infringed by Power Integrations. Following trial, the 

district court granted Power Integrations’ motion for 

judgment as a matter of law (JMOL) that Fairchild directly infringed the ’605 patent, but denied the parties’ other 

JMOL motions and motions for a new trial. Power Integrations, Inc. v. Fairchild Semiconductor Int’l, Inc., 935 F. 

Supp. 2d 747 (D. Del. 2013) (JMOL Decision). The court 

subsequently granted Power Integrations’ motion for a 

permanent injunction and denied Fairchild’s motion for a 

permanent injunction. Power Integrations, Inc. v. 

Fairchild Semiconductor Int’l, Inc., No. 1:08-cv-00309-

LPS, 2014 WL 2960035 (D. Del. June 30, 2014) (Permanent Injunction Order); Power Integrations, Inc. v. 

Fairchild Semiconductor Int’l, Inc., No. 1:08-cv-00309-

LPS (D. Del. June 16, 2014) (Dkt. No. 790). The district 

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POWER INTEGRATIONS v. FAIRCHILD SEMICONDUCTOR 3

court entered final judgment as to liability on January 13, 

2015. Power Integrations, Inc. v. Fairchild Semiconductor 

Int’l, Inc., No. 1:08-cv-00309-LPS (D. Del. Jan. 13, 2015) 

(Dkt. No. 819). All damages claims were bifurcated by the 

district court and remain pending.

Fairchild appeals and Power Integrations crossappeals various decisions from the district court.1 We 

hold as follows:

• The jury’s verdict that the asserted claims of the 

’876 patent were not anticipated by Martin2 or 

Wang3 is affirmed. 

• Because the district court’s jury instruction incorrectly stated the law on inducement, the jury’s verdict that Fairchild induced infringement of the 

asserted claims of the ’876 and ’851 patents is vacated. 

• The jury’s verdict that the asserted claims of the 

’605 patent were not anticipated by Maige4 is reversed. 

• The district court’s construction that the asserted 

claims of the ’972 patent require “sampling a voltage from the auxiliary winding of the transformer 

when the transformer is discharging” is affirmed. 

 

1 Neither party appeals the jury’s verdicts on the 

’270 and ’595 patents.

2 U.S. Patent No. 4,638,417. 3 Andrew C. Wang and Seth R. Sanders, Programmed Pulsewidth Modulated Waveforms for Electromagnetic Interference Mitigation in DC-DC Converters, 

IEEE Transactions on Power Electronics, Vol. 8, No. 4 

(Oct. 1993). 4 U.S. Patent No. 4,763,238. 

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• The jury’s verdict that the asserted claims of the 

’972 patent would not have been obvious in view of 

Majid5 is affirmed. 

• The jury’s verdict that Power Integrations infringed 

the asserted claims of the ’972 patent under the 

doctrine of equivalents is reversed. 

• The district court’s grant of Power Integrations’ 

motion for a permanent injunction is vacated in 

view of the above holdings.

• The district court’s denial of Fairchild’s motion for 

a permanent injunction is moot in view of the above 

holdings.

In sum, we affirm-in-part, reverse-in-part, and vacatein-part the final judgment entered by the district court 

and remand for further proceedings.

BACKGROUND

Power Integrations and Fairchild are direct competitors in the power supply controller chip market. They 

have engaged in a long-running and multi-fronted patent 

dispute involving actions in at least the United States 

District Courts for the District of Delaware6 and the 

Northern District of California,7 as well as the United 

States Patent and Trademark Office Patent Trial and 

 

5 U.S. Patent No. 5,956,242. 6 See Power Integrations, Inc. v. Fairchild Semiconductor Int’l, Inc., No. 1:08-cv-00309-LPS (D. Del. filed May 

23, 2008); Power Integrations, Inc. v. Fairchild Semiconductor Int’l, Inc., No. 1:04-cv-01371-LPS (D. Del. filed Oct. 

20, 2004).

7 See Power Integrations, Inc. v. Fairchild Semiconductor Int’l, Inc., No. 3:09-cv-05235-MMC (N.D. Cal. filed 

Nov. 4, 2009).

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Appeal Board.8 We are not unfamiliar with the parties or 

their disputes. In fact, we have heard appeals of at least 

two decisions that involved two of the very patents at 

issue here. See Power Integrations, Inc. v. Lee, 797 F.3d 

1318 (Fed. Cir. 2015) (vacating Patent Board’s decision

that claims of the ’876 patent were unpatentable as

anticipated); Power Integrations, Inc. v. Fairchild Semiconductor Int’l, Inc., 711 F.3d 1348 (Fed. Cir. 2013) (reviewing jury verdict on ’851 and ’876 patents, among 

others).

Power supplies are ubiquitous in modern society. Anyone who has purchased an electronic device in recent 

times—whether a cellular phone, computer, television, or 

the like—is familiar with the different cords and plugs 

provided to power and/or charge those devices. Somewhere in the cord/plug combination resides a power 

supply. The power supply is often integrated into the 

plug itself, as is the case with many cellular phones. In 

other configurations, the power supply resides in a 

standalone module, as with many laptop computers.

Figure 1: Power supply Figure 2: Power supply as 

 

8 See Power Integrations, Inc. v. Fairchild Semiconductor Corp., No. 2015-00769, 2015 WL 9595648 (PTAB 

Dec. 31, 2015); see also Ex parte Power Integrations, Inc., 

No. 2010-011021, 2010 WL 5244756 (BPAI Dec. 22, 2010).

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integrated into plug a standalone module

The power supply does more than simply allow power 

to flow from a wall outlet to the connected electronic 

device. Power supplies serve the integral role of converting the power supplied by the wall outlet into a form the 

electronic device can use. The power a wall outlet provides is of a relatively high voltage and uses alternating 

current (AC). In contrast, electronic devices generally 

require a relatively low voltage and direct current (DC). 

These devices would likely be damaged if exposed to highvoltage AC power. Power supplies convert the highvoltage AC power supplied by the wall outlet into the lowvoltage DC power required by the electronic device.9

The controller chip is the “brains” of the power supply. 

It ensures that the power supply functions properly. Over 

time, controller chips have evolved to incorporate new 

features that make power supplies smaller, cheaper, and 

more efficient. The patents at issue in this appeal relate 

to some of the features that have been incorporated into 

modern controller chips.

I. The ’851 and ’876 Patents

Power Integrations is the assignee of the ’851 and ’876 

patents. These patents relate to “frequency jitter” in 

power supplies.

Modern power supplies operate in what is known as 

“switched mode.” Switched-mode power supplies conserve 

energy by rapidly switching between on and off states. 

They differ from older, linear power supplies, which 

remained in an on state. The switched-mode power 

supply’s controller chip commands the alternating on/off 

 

9 For a more detailed explanation of AC and DC 

power and the conversion between the two, see our prior 

opinion in Power Integrations, 711 F.3d at 1357–58.

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states through the use of an oscillator. Prior art switchmode power supplies most often used a high-frequency

oscillator operating at a fixed frequency. ’851 patent, 

1:22–26; ’876 patent, 1:12–18. The fixed, high-frequency 

operation of the oscillator tended to inject noise in the 

form of electromagnetic interference (EMI) into the power 

supply at the specific frequency of the oscillator. This 

noise would, in turn, impact the operation of downstream 

and co-located components. ’851 patent, 1:22–40; ’876 

patent, 1:19–33.

The ’851 and ’876 patents claim circuits that “jitter”—

or vary—the frequency of the controller chip’s oscillator to 

reduce the amount of EMI the switched-mode power 

supply generates. ’851 patent, 3:43–48; ’876 patent, 1:66–

67. One form of jitter is captured in Figure 2 of the ’876

patent:

As shown in the figure, the oscillator frequency increases 

by a fixed amount every eight clock cycles before resetting 

after 128 clock cycles. By jittering the oscillator frequency—using a step function like the one shown above or 

some other scheme—the power supply divides any EMI it 

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POWER INTEGRATIONS v. FAIRCHILD SEMICONDUCTOR 9

The invention of the ’605 patent attempts to solve this 

problem. It introduces a regulator to the current-limiting 

circuit that steadily increases the current threshold 

during the time the power supply is in an on state. ’605 

patent, 1:51–59. This variable current limit is shown in 

Figure 2 of the ’605 patent:

The square wave—labeled “Duty Cycle Max 15”—

represents the alternating on and off states of the power 

supply: when the wave is high, the power supply is on; 

when the wave is low, the power supply is off. The current limit (i.e., “Intrinsic Current Limit 22”) steadily 

increases throughout the period the power supply is on; it 

decreases throughout the period the power supply is off.

This increasing current limit provides advantages 

over prior art power supplies. For instance, with this 

improved design, an immediate surge in output current 

will trip the current limit at a lower level. This offers 

additional protection to downstream components without 

impacting operation of the power supply at normal power 

levels. 

III. The ’972 Patent

Fairchild is the assignee of the ’972 patent. The ’972 

patent is a combination patent and claims a power supply 

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that includes frequency jitter—similar to that claimed in

the ’851 and ’876 patents—and overcurrent protection—

similar to the claimed invention of the ’605 patent. ’972 

patent, 1:9–12.

However, the ’972 patent discloses an approach to 

overcurrent protection that differs from that of the ’605 

patent. Whereas the regulator claimed in the ’605 patent 

monitored the power supply’s output voltage and current 

at the actual output of the power supply, ’605 patent, 

6:16–18, the power converter claimed in the ’972 patent 

monitors the output voltage and current at what is known 

as the “primary side” of the power supply’s transformer, 

’972 patent, 2:42–46. 

This is best explained with reference to Figure 1 of 

the ’972 patent:

The figure is a schematic diagram of a power supply. Id.

at 2:62–64. The transformer, labeled “10,” divides the 

power supply. All circuitry to the left of transformer 10 in 

the schematic is the “primary side” of the power supply; 

all circuitry to the right of transformer 10 is the “secondary side” of the power supply. See id. at 2:64–66. Power 

supplies use a transformer to isolate the input terminals 

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POWER INTEGRATIONS v. FAIRCHILD SEMICONDUCTOR 11

of the power supply (VIN) from the output terminals (VO) 

for safety and reliability reasons. Id. at 1:17–20. 

Prior art power supplies, like that claimed in the ’605 

patent, monitored output voltage and/or current on the 

secondary side of the power supply. Id. at 1:24–30. Such 

a scheme required a regulator on the secondary side as 

well as an opto-coupler to provide feedback from the 

secondary side of the power supply to the primary side. 

Id. at 1:30–33. The addition of these components increased the size and cost of the power supply. Id.

The power supply claimed in the ’972 patent, in contrast, controls the output power at the primary side of the 

transformer based on feedback received on the primary 

side. Id. at 2:42–46. The power supply thereby does not 

require the secondary-side regulator or the opto-coupler 

found on prior art devices. Id. at 2:50–51. As a result, 

the power supply could be smaller in size and lower in 

cost.

PROCEDURAL HISTORY

Power Integrations filed suit against Fairchild on May 

23, 2008 in the District of Delaware alleging that 

Fairchild directly and indirectly infringed the ’851, ’876, 

and ’270 patents. Power Integrations subsequently 

amended its complaint to add allegations that Fairchild 

directly and indirectly infringed the ’605 patent. 

Fairchild filed counterclaims alleging that Power Integrations directly and indirectly infringed the ’972 and ’595

patents and U.S. Patent No. 7,061,780. Each party denied the infringement allegations made against it and 

alleged that all patents asserted against it were invalid 

and/or unenforceable. 

The district court bifurcated the liability and damages 

phases of the case prior to trial. A ten-day jury trial on 

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liability commenced on April 11, 2012.10 At the conclusion of trial, the jury returned a mixed verdict. The jury 

found all claims asserted by Power Integrations not 

invalid. Specifically, the jury found claims 1 and 2 of the 

’605 patent neither anticipated nor obvious; claims 6 and 

7 of the ’270 patent neither anticipated nor obvious; 

claims 1 and 21 of the ’876 patent not anticipated; and 

claim 18 of the ’851 patent not anticipated. 

The jury found Fairchild liable for infringement of the 

’876 and ’851 patents. It found that: Fairchild’s 

SG5841J-type products did not literally infringe claims 1 

or 21 of the ’876 patent but did infringe those claims 

under the doctrine of equivalents; Fairchild’s FAN103-

type products literally infringed claims 1 and 21 of the 

’876 patent; Fairchild induced others to infringe claims 1 

and 21 of the ’876 patent; Fairchild’s SG5841J- and 

SG6842J-type products literally infringed claim 18 of the 

’851 patent; and Fairchild induced others to infringe claim 

18 of the ’851 patent. The jury found that Fairchild did 

not directly infringe or induce infringement of claims 1 or 

2 of the ’605 patent or claims 6 or 7 of the ’270 patent. 

Turning to Fairchild’s patents, the jury found all asserted claims not invalid. In particular, the jury found 

claims 6, 7, 18, and 19 of the ’972 patent not obvious and 

claims 17 and 22 of the ’595 patent not anticipated. On 

infringement, the jury found for Fairchild under a single 

theory: Power Integrations infringed the asserted claims 

of the ’972 patent under the doctrine of equivalents. The 

jury found that Power Integrations did not literally infringe those claims nor did it induce others to infringe 

those claims. The jury found that Power Integrations did 

not infringe the asserted claims of the ’595 patent literally, under the doctrine of equivalents, or by inducement.

 

10 By the time of trial, the ’780 patent was no longer 

at issue.

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The parties filed a multitude of post-trial motions 

challenging aspects of the jury’s verdict or seeking a new 

trial. The district court granted Power Integrations’ 

motion for JMOL of direct infringement of the ’605 patent. 

JMOL Decision, 935 F. Supp. 2d at 756. It denied all 

other motions. Id. at 764. 

Later, the court granted Power Integrations’ motion 

for a permanent injunction and enjoined “Fairchild from

selling, offering to sell, and importing the products found

at trial to infringe and those products ‘not colorably

different’ from them.” Permanent Injunction Order, 2014 

WL 2960035, at *2. The district court denied Fairchild’s 

motion for a permanent injunction. 

The district court entered final judgment as to liability on January 13, 2015. Fairchild filed a timely appeal 

and Power Integrations cross-appealed. We have jurisdiction pursuant to 28 U.S.C. § 1295(a)(1). 

DISCUSSION

The parties raise twelve issues on appeal. The issues 

can be categorized as follows: (1) challenges to the district 

court’s construction of certain claim terms; (2) a challenge 

to the district court’s jury instructions; (3) a challenge to 

the verdict form adopted by the district court; (4) challenges to the district court’s denial of certain of the parties’ motions for JMOL; (5) challenges to the district 

court’s denial of certain of the parties’ motions for a new 

trial; and (6) challenges to the district court’s grant or 

denial of a party’s motion for a permanent injunction.

We apply the framework established in Teva Pharmaceuticals U.S.A., Inc. v. Sandoz, Inc. when reviewing a

district court’s construction of a patent’s claims. 135 S. 

Ct. 831, 835 (2015). Under that framework, we review 

the district court’s ultimate claim construction de novo

with any underlying factual determinations involving 

extrinsic evidence reviewed for clear error. Id. at 841–42. 

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We review “the legal sufficiency of jury instructions on 

an issue of patent law without deference to the district 

court.” DSU Med. Corp. v. JMS Co., Ltd., 471 F.3d 1293, 

1304 (Fed. Cir. 2006) (en banc). “A jury verdict will be set 

aside only if the jury instructions were ‘legally erroneous’ 

and the ‘errors had prejudicial effect.’” Ericsson, Inc. v. DLink Sys., Inc., 773 F.3d 1201, 1225 (Fed. Cir. 2014) 

(quoting Sulzer Textil A.G. v. Picanol N.V., 358 F.3d 1356, 

1363 (Fed. Cir. 2004)).

We review the verdict form adopted by the district 

court for an abuse of discretion. See Wyers v. Master Lock 

Co., 616 F.3d 1231, 1248 (Fed. Cir. 2010) (“[I]t must be 

left to the sound discretion of the trial court what form of 

verdict to request of a jury.” (quoting Structural Rubber 

Prods. Co. v. Park Rubber Co., 749 F.2d 707, 720 (Fed. 

Cir. 1984))). 

“We review the denial of a motion for JMOL . . . under 

the law of the pertinent regional circuit. The Third Circuit exercises plenary review of a denial of JMOL, applying the same standard as the district court.” Siemens 

Med. Sols. USA, Inc. v. Saint-Gobain Ceramics & Plastics, 

Inc., 637 F.3d 1269, 1277–78 (Fed. Cir. 2011) (citations 

omitted). “To prevail on a renewed motion for JMOL 

following a jury trial, a party must show that the jury’s 

findings, presumed or express, are not supported by 

substantial evidence or, if they were, that the legal conclusion(s) implied by the jury’s verdict cannot in law be 

supported by those findings.” Pannu v. Iolab Corp., 155 

F.3d 1344, 1348 (Fed. Cir. 1998) (internal quotation 

marks and citations omitted). 

“In reviewing a district court’s disposition of . . . a new 

trial motion, this court applies the law of the regional 

circuit where the district court sits.” Bettcher Indus., Inc. 

v. Bunzl USA, Inc., 661 F.3d 629, 638 (Fed. Cir. 2011)

(citation omitted). The Third Circuit “review[s] a district 

court’s grant or denial of a new trial motion by applying 

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POWER INTEGRATIONS v. FAIRCHILD SEMICONDUCTOR 15

ing.” Olefins Trading, Inc. v. Han Yang Chem Corp., 9

F.3d 282, 289 (3d Cir. 1993).

We review a district court’s ultimate decision to grant 

or deny a permanent injunction for an abuse of discretion. 

Apple, Inc. v. Samsung Elecs. Co., Ltd., 809 F.3d 633, 639 

(Fed. Cir. 2015). We review the district court’s conclusions on each of the underlying factors set forth in eBay 

Inc. v. MercExchange, LLC, 547 U.S. 388 (2006), for an 

abuse of discretion and its underlying factual findings for 

clear error. Apple, 809 F.3d at 639. 

For simplicity, we address all issues associated with a 

particular patent—or group of patents—together. We 

therefore depart from our normal practice and intersperse 

the issues raised in Fairchild’s appeal with the issues 

raised in Power Integrations’ cross-appeal as necessary. 

I. The ’851 and ’876 Patents (Frequency Jitter) 

Fairchild commits much of its briefing to its argument 

that it is entitled to JMOL that it did not induce infringement of the ’851 and ’876 patents or, at the very 

least, that it is entitled to a new trial on the issue. Before 

reaching the jury’s induced infringement verdict, however, we must first address Fairchild’s argument that claims 

1 and 21 of the ’876 patent are invalid as anticipated.11

A. Validity of the ’876 Patent

The jury found that neither Martin nor Wang anticipated claims 1 and 21 of the ’876 patent. The ’876 patent 

claims a “frequency jittering” circuit used in switchedmode power supplies to reduce EMI emissions produced 

by the power supply. ’876 patent, Abstract. Claim 1 

reads as follows:

 

11 Fairchild does not appeal the jury’s verdict that 

claim 18 of the ’851 patent was not invalid as anticipated.

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1. A digital frequency jittering circuit for varying 

the switching frequency of a power supply, comprising:

an oscillator for generating a signal having a switching frequency, the oscillator 

having a control input for varying the 

switching frequency;

a digital to analog converter coupled to the 

control input for varying the switching 

frequency; and

a counter coupled to the output of the oscillator and to the digital to analog converter, 

the counter causing the digital to analog 

converter to adjust the control input and 

to vary the switching frequency.

Id. at 8:42–53 (emphases added). Claim 21 is similar. It 

too is directed to a “frequency jittering circuit.” Id. at 

9:55–65. It includes a limitation analogous to the one 

emphasized above in claim 1: “a counter coupled to the 

output of the oscillator and to the one or more current 

sources.” Id. at 9:64–65.

Martin and Wang each disclose a controller circuit 

used to reduce the EMI signature associated with a power 

supply’s oscillator. See Martin, 1:55–56; Wang at 585. 

The circuits accomplish this reduction by varying the 

oscillator frequency through the use of a pseudo-random 

code stored in read-only memory (ROM). See, e.g., Martin, 1:53–55. The below figure from Martin is exemplary:

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Martin, Fig. 1. In this circuit, counter 10 acts as an index 

to EPROM 11. As the output of counter 10 increases, it 

accesses the pseudo-random code value stored at the 

corresponding address of EPROM 11. Id. at 2:39–44. 

This value is outputted to digital-to-analog converter 12, 

which in turn drives the circuit’s oscillator (i.e., VCO 13). 

Id. at 2:44–49. The result is an oscillator with a frequency that varies according to the pseudo-random code stored 

in EPROM 11.

At trial, Power Integrations disputed Fairchild’s argument that Martin and Wang anticipated claims 1 and 

21. It argued to the jury that the invention of the ’876 

patent differed from the prior art references in at least 

two key ways: (1) the circuits of Martin and Wang do not 

vary about a “target frequency” as required by the district 

court’s construction of “frequency jittering;” and (2) the 

counters of Martin and Wang are not “coupled” to the 

digital-to-analog converter as the district court construed 

that term. The jury agreed and found that the claims 

were not anticipated by Martin or Wang.

We find that the jury’s verdict was supported by substantial evidence. The district court construed “frequency 

jittering” to mean “varying the switching frequency of a 

switch mode power supply about a target frequency in 

order to reduce electromagnetic interference.” Power 

Integrations, Inc. v. Fairchild Semiconductor Int’l, Inc., 

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No. 1:08-cv-00309-LPS, 2009 WL 4928029, at *20 (D. Del. 

Dec. 18, 2009) (Claim Construction Order).12 Fairchild 

does not challenge this construction. Rather, it contends 

that the claim limitation was disclosed in the prior art, 

using an argument akin to the symmetric property in 

mathematics.13 Fairchild first notes that one type of 

target frequency (“a”) disclosed in the ’876 patent is an 

average frequency (“b”). It next contends that one can 

take the pseudo-random frequencies used in Martin and 

Wang and calculate an average frequency (“b”). It finally 

argues that if the ’876 patent’s target frequency can be an 

average frequency (i.e., a = b), then Martin’s and Wang’s 

average frequency (that Fairchild proposed can be calculated) must be a target frequency (i.e., b = a).

While Fairchild’s argument is creative, it fails to account for the temporal aspect of the district court’s claim 

construction. The district court explained that “frequency 

jittering” requires “varying the switching frequency of a 

switch mode power supply about a target frequency in 

order to reduce electromagnetic interference.” Id. Under 

this construction, the claimed circuit—or its designer—

must have a priori knowledge of the target frequency in 

order to vary the switching frequency about that target 

frequency. See id. (explaining that the patent specification “refer[s] to varying the switching frequency about a 

narrow, known, or fixed range of frequencies in order to 

reduce EMI”). As the district court correctly noted, 

Fairchild’s proposed calculation of Martin’s and Wang’s 

average frequency is done entirely “after the fact.” JMOL 

Decision, 935 F. Supp. 2d at 761 (“Calculating an average 

frequency after the fact does not teach one of skill in the 

art how to vary the switching frequency, and does not 

 

12 The district court adopted then-Magistrate Judge 

Stark’s Report and Recommendation Regarding Claim 

Construction on July 20, 2010. J.A. 49–50.

13 Under the symmetric property, if a = b then b = a.

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produce the desired result of reducing electromagnetic 

interference.”). Neither reference teaches use of a known

target frequency about which switching frequencies are 

varied. Therefore, substantial evidence supports the 

jury’s findings that the references do not anticipate claim 

1 or 21.

Martin and Wang likewise do not teach the “coupled 

to” limitations of claims 1 and 21. The district court 

construed “coupled” to mean that “two circuits are coupled 

when they are connected such that voltage, current or 

control signals pass from one to another.” J.A. 17137. 

Martin and Wang each disclose a circuit that includes a 

counter linked to a digital-to-analog converter by way of a 

ROM. See Martin, Fig. 1; Wang at 604. The ROM takes 

the output of the upstream counter as its input. Martin, 

2:22–24; Wang at 604. It then outputs a different, stored 

value to the digital-to-analog converter. Martin, 2:29–32; 

Wang at 604. The addition of the ROM thereby ensures 

that no “voltage, current or control signals pass from” the 

counter to the digital-to-analog converter. In other words, 

the ROM “decouples” the counter from the digital-toanalog converter. As such, substantial evidence supports 

the jury verdict that neither Martin nor Wang anticipates 

claim 1 or 21. The district court therefore correctly denied 

Fairchild’s JMOL motion.

B. Induced Infringement of the ’851 and ’876 Patents

The jury found that Fairchild’s SG5841J- and 

SG6842J-type products literally infringed claim 18 of the 

’851 patent; its SG5841J-type products infringed claims 1 

and 21 of the ’876 patent under the doctrine of equivalents; and its FAN103-type products literally infringed 

claims 1 and 21 of the ’876 patent. The jury further found 

that Fairchild induced others to infringe these claims. 

Fairchild does not appeal the jury’s direct infringement 

verdicts. It does appeal the jury’s indirect infringement 

verdicts.

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20 POWER INTEGRATIONS v. FAIRCHILD SEMICONDUCTOR

Fairchild raises three issues with respect to the jury’s 

induced infringement verdict. Fairchild first argues that 

the verdict should be reversed because its foreign sales of 

and sales activities related to the infringing products 

cannot constitute specific intent to bring about infringement in the United States. Alternatively, Fairchild 

argues that the verdict should be vacated because the jury 

was improperly instructed that Fairchild need not successfully induce a third party to infringe to be liable for 

induced infringement. Finally, Fairchild argues that the 

district court’s failure to include interrogatories on the 

verdict form requiring identification of direct infringers is 

a separate ground to vacate the jury verdict.

We agree with Fairchild that the district court’s jury 

instruction misstated the law on induced infringement in 

a way that prejudiced Fairchild. We therefore vacate the 

jury’s verdict. Because we do not find that the record as a 

whole requires a finding of non-infringement as a matter 

of law, we do not go further and, as Fairchild requests, 

enter judgment in its favor. Our decision to vacate the 

jury verdict due to the improper jury instruction renders 

Fairchild’s argument with respect to the verdict form 

moot.14

 

14 While we do not reach Fairchild’s appeal on the 

verdict form, we are not unsympathetic to the Seventh 

Amendment concerns Fairchild raises. On remand, we 

“le[ave] to the sound discretion of the trial court what 

form of verdict to request of a jury.” Wyers, 616 F.3d at 

1248. We nonetheless note that the court’s decision to 

bifurcate liability and damages in this case does raise the 

possibility that both the liability jury and the damages 

jury will be asked to determine which of Fairchild’s customers were induced to infringe by Fairchild. Such a 

result may run afoul of the Seventh Amendment. See 

Blyden v. Mancusi, 186 F.3d 252, 268 (2d Cir. 1999) 

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POWER INTEGRATIONS v. FAIRCHILD SEMICONDUCTOR 21

i. Jury Instruction

Induced infringement is defined in 35 U.S.C. § 271(b): 

“Whoever actively induces infringement of a patent shall 

be liable as an infringer.” 

In the lead-up to trial, Power Integrations and 

Fairchild proposed competing jury instructions on induced 

infringement. Fairchild’s proposed instruction tracked 

the then-current Federal Circuit Bar Association model, 

while Power Integrations’ proposal was a variation of an 

instruction given in a prior trial in the District of Delaware. The parties’ dispute continued through trial, with 

each party advocating for its proposed instruction and 

objecting to its opponent’s proposed instruction. 

The district court adopted an instruction that largely 

tracked the one proposed by Power Integrations. It read: 

Each party alleges that the other is liable for infringement by actively inducing others to directly 

infringe the patents in suit. The direct infringement may either be literal or under the doctrine of 

equivalents. A party induces patent infringement 

if it purposefully causes, urges, or encourages another to use a product in a manner that infringes 

an asserted claim. Inducing infringement cannot 

occur unintentionally.

A party is liable for active inducement only if the 

patent owner proves by a preponderance of the evidence that:

 

(“Issues may be divided and tried separately, but a given 

issue may not be tried by different successive juries.” 

(citing Byrd v. Blue Ridge Rural Elec. Coop., 356 U.S. 525, 

537–38 (1958); Gasoline Prods. Co. v. Champlin Ref. Co., 

283 U.S. 494, 500 (1931))).

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22 POWER INTEGRATIONS v. FAIRCHILD SEMICONDUCTOR

1. the party took some action during the 

time the patents in suit were in force 

intending to encourage or assist actions by others;

2. the party was aware of the patent and 

knew that the acts, if taken, would 

constitute infringement of that patent 

or the party believed there was a high 

probability that the acts, if taken, 

would constitute infringement of the 

patent but deliberately avoided confirming that belief; and

3. use by others of the party’s product infringes one or more of the asserted 

claims of the patent.

In order to establish active inducement of infringement, it is not sufficient that others directly 

infringe the claim. Nor is it sufficient that the 

party accused of infringement was aware of the 

acts by others that directly infringe. Rather, in 

order to find inducement, you must find that the 

party accused of infringement intended others to 

use its products in at least some ways that would 

infringe the asserted claims of the patent. However, that infringement need not have been actually 

caused by the party’s actions. All that is required 

is that the party took steps to encourage or assist 

that infringement, regardless of whether that encouragement succeeded, or was even received.

Intent to encourage or assist the acts that constitute direct infringement must be proven by evidence of active steps taken to encourage direct 

infringement, such as providing products, advertising any infringing use, or instructing how to 

engage in any use that is infringing.

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POWER INTEGRATIONS v. FAIRCHILD SEMICONDUCTOR 23

Proof of intent to induce infringement may be 

based on circumstantial evidence, rather than direct evidence.

J.A. 510–11 (emphasis added). 

This instruction left the jury with the incorrect understanding that a party may be liable for induced infringement even where it does not successfully communicate 

with and induce a third-party direct infringer.15 The 

Supreme Court has explained that the term “induce” as it 

is used in § 271(b) “means ‘[t]o lean on; to influence; to 

prevail on; to move by persuasion.” Global-Tech Appliances, Inc. v. SEB S.A., 563 U.S. 754, 760 (2011) (alteration in original) (citations omitted). Each definition 

requires successful communication between the alleged 

inducer and the third-party direct infringer.

 

15 Power Integrations argues that Fairchild did not 

preserve this issue for appeal. Appellee’s Opening Br. 44–

46. We disagree. Fairchild repeatedly and consistently 

argued to the district court—in the context of the jury 

instructions and the verdict form—that a finding of 

induced infringement required evidence that Fairchild 

actually induced third-party direct infringers. See, e.g., 

J.A. 16946–47 (1941:18–1942:4).* Moreover, Fairchild 

expressly objected to the jury instruction on induced 

infringement. J.A. 17179 (2495:6–9) (“Your Honor, we 

want to make sure we state on the record that we object 

to Jury Instruction 4.5 and we are very interested to see 

how we sort this out at a later point in time, depending on 

the verdict.”).

* The trial transcript included in the joint appendix 

contains four transcript pages for each single page of the 

joint appendix. Whenever citing to the trial transcript, 

we cite to both the joint appendix page(s) (i.e., J.A. #####) 

and the specific trial transcript page(s) and line(s) (i.e., 

PPPP:LL–PPPP:LL). 

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24 POWER INTEGRATIONS v. FAIRCHILD SEMICONDUCTOR

We have further held that “[t]o prevail under a theory 

of indirect infringement, [plaintiff] must first prove that 

the defendants’ actions led to direct infringement of the 

[patent-in-suit].” Dynacore Holdings Corp. v. U.S. Philips 

Corp., 363 F.3d 1263, 1274 (Fed. Cir. 2004) (citation 

omitted); see also DSU Med. Corp., 471 F.3d at 1304 

(“[T]he plaintiff has the burden of showing that the alleged infringer’s actions induced infringing acts . . . .”

(internal quotation marks and citation omitted)); Crystal 

Semiconductor Corp. v. TriTech Microelecs. Int’l, Inc., 246 

F.3d 1336, 1351 (Fed. Cir. 2001) (induced infringement 

occurs only “if the party being induced directly infringes 

the patent” (citation omitted)). 

Under this precedent, a finding of induced infringement requires actual inducement. The inducement may 

be proven via circumstantial evidence. See MEMC Elec. 

Materials, Inc. v. Mitsubishi Materials Silicon Corp., 420 

F.3d 1369, 1380 (Fed. Cir. 2005) (finding “sufficient 

circumstantial evidence for a reasonable jury to conclude 

that [defendant] was not only aware of the potentially 

infringing activities in the United States by [a third-party 

infringer], but also that [defendant] intended to encourage 

those activities” (citations omitted)). But the jury must 

still find that it occurred. The jury instruction incorrectly 

stated that liability exists even where no inducement 

actually occurred. This is contrary to the law.

Power Integrations attempts to salvage the jury instruction—and, by extension, the jury verdict—by claiming that the disputed portion of the instruction related to 

Fairchild’s intent to induce a third-party direct infringer, 

not whether Fairchild actually induced a third party. It 

cites the Supreme Court’s decision in Grokster16 and our 

 

16 Metro-Goldwyn-Mayer Studios Inc. v. Grokster, 

Ltd., 545 U.S. 913 (2005).

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POWER INTEGRATIONS v. FAIRCHILD SEMICONDUCTOR 25

decision in Ricoh17 for the proposition that “a defendant’s 

acts to encourage direct infringement are probative of an 

unlawful intent, even if customers do not learn of them or 

the acts don’t cause the customers’ direct infringement.” 

Appellee’s Opening Br. 46. Power Integrations’ statement 

of the law is correct. However, it is irrelevant here. The 

district court instructed the jury that “[direct] infringement need not have been actually caused by the [alleged 

inducer]’s actions. All that is required is that the party 

took steps to encourage or assist that infringement, 

regardless of whether that encouragement succeeded, or 

was even received.” J.A. 510. Nothing in this statement 

suggests that it applies to simply Fairchild’s intent to 

induce infringement. Rather, it expressly misstates the 

law on actual inducement. See Dynacore, 363 F.3d at 

1274 (“To prevail under a theory of indirect infringement, 

Dynacore must first prove that defendants’ actions led to 

direct infringement of the [patent-in-suit].”).

We conclude that the district court’s instruction misstated the law of induced infringement. As discussed 

more fully below, Power Integrations’ claim for induced 

infringement was a close call. Therefore, we cannot say 

that the instruction did not tip the scales in favor of 

Power Integrations at trial. We thus vacate the jury’s 

verdict that Fairchild induced infringement of the ’851 

and ’876 patents. See Ericsson, 773 F.3d 1201, 1225 (Fed. 

Cir. 2014) (“A jury verdict will be set aside only if the jury 

instructions were ‘legally erroneous’ and the ‘errors had 

prejudicial effect.’” (citation omitted)). 

ii. Jury Verdict

While we have already determined that the flawed jury instruction requires that we vacate the jury’s verdict, 

we must still address Fairchild’s argument that it is 

 

17 Ricoh Co., Ltd. v. Quanta Computer, Inc., 550 

F.3d 1325 (Fed. Cir. 2008).

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26 POWER INTEGRATIONS v. FAIRCHILD SEMICONDUCTOR

entitled to JMOL of no induced infringement. After all, if 

Power Integrations did not present sufficient evidence to 

allow a reasonable jury to find in its favor, a new trial on 

induced infringement would be unnecessary—and improper—regardless of the jury instruction given by the 

district court. See Verizon Servs. Corp. v. Cox Fibernet 

Va., Inc., 602 F.3d 1325, 1337–38 (Fed. Cir. 2010) (“In 

reviewing the jury verdict of obviousness, we review 

whether the jury was correctly instructed on the law, and 

whether there was substantial evidence whereby a reasonable jury could have reached its verdict upon application 

of the correct law to the facts, recognizing that invalidity 

must be proved by clear and convincing evidence.” (emphasis added) (citation omitted)). Because the evidentiary 

record permits more than one reasonable finding on 

induced infringement, we cannot say that, had the jury 

been instructed properly, the jury’s verdict would have 

lacked substantial supporting evidence. Therefore, we do 

not enter judgment in favor of Fairchild. 

“To prove inducement of infringement, the patentee 

must []show that the accused inducer took an affirmative 

act to encourage infringement with the knowledge that 

the induced acts constitute patent infringement.” Astornet Techs. Inc. v. BAE Sys., Inc., 802 F.3d 1271, 1279 

(Fed. Cir. 2015) (quoting Info-Hold, Inc. v. Muzak LLC, 

783 F.3d 1365, 1372 (Fed. Cir. 2015)). In other words, 

Power Integrations was required to prove that: (1) a third 

party directly infringed the asserted claims of the ’851 

and ’876 patents; (2) Fairchild induced those infringing 

acts; and (3) Fairchild knew the acts it induced constituted infringement. 

Fairchild does not seriously dispute that Power Integrations proved infringement of the ’851 and ’876 patents 

by third parties. Power Integrations presented evidence 

that it purchased at least three products containing 

infringing Fairchild chips in the United States: an HP 

printer packaged with an Astec power supply that conCase: 15-1329 Document: 87-2 Page: 26 Filed: 12/12/2016
POWER INTEGRATIONS v. FAIRCHILD SEMICONDUCTOR 27

tained an infringing Fairchild SG6846A controller chip; 

an Acer notebook computer packaged with a Lite-On 

power supply that contained an infringing Fairchild 

LTA703S controller chip; and a Samsung notebook computer packaged with a power supply that contained an 

infringing SG6842J controller chip. Fairchild makes no 

argument that these controller chips do not necessarily 

infringe the relevant claims of the ’851 and ’876 patents if 

made, used, or sold in the United States. See Appellants’ 

Opening Br. 19 (conceding that Power Integrations proved 

“limited instances . . . of direct infringement by thirdparty sellers”).

Fairchild likewise does not seriously dispute it knew 

that importation, use, and sale of these controller chips in 

the United States constituted infringement of the ’851 

and ’876 patents. In the single paragraph of argument on 

this issue in its briefing, Fairchild cites the conclusory 

trial testimony of one of its executives that he and his 

sales team told customers that “we don’t infringe the 

Power Integrations patents” and makes the equally 

conclusory statement that “Fairchild presented strong 

non-infringement defenses as to both patents.” Appellants’ Opening Br. 32–33 (quoting J.A. 16787 (1470:3)). 

Fairchild needs more to meet its burden of “show[ing]

that the jury’s findings . . . are not supported by substantial evidence,” as it must to succeed on appeal. Pannu, 

155 F.3d at 1348. This is particularly true considering

this court has already found that “Fairchild competed 

with Power Integrations by reverse engineering and 

copying of Power Integrations’ products” and that 

“Fairchild fostered a corporate culture of copying” with 

respect to at least the ’876 patent. Power Integrations, 

711 F.3d at 1369. 

Fairchild’s appeal instead focuses on whether substantial evidence supports the jury’s verdict that Fairchild 

actually induced third-party direct infringement. 

Fairchild explains that it sells its controller chips overCase: 15-1329 Document: 87-2 Page: 27 Filed: 12/12/2016
28 POWER INTEGRATIONS v. FAIRCHILD SEMICONDUCTOR

seas into a worldwide distribution system with no 

knowledge of where its chips will ultimately end up. It 

contends that, because it sells the same chips for use in 

foreign and domestic markets, its sales activities are

market agnostic and Power Integrations “marshaled no 

evidence that Fairchild took affirmative steps to encourage incorporation of the accused products into U.S.-bound 

products with the specific intent to induce infringement.” 

Appellants’ Opening Br. 25.

We disagree with Fairchild’s characterization of the 

evidence. Power Integrations, in fact, introduced significant—though not necessarily overwhelming—evidence 

that would allow a jury to find that Fairchild took affirmative acts to induce third parties to import its products 

into the United States. As examples, Power Integrations 

presented evidence that: Fairchild designed its controller 

chips to meet certain United States energy standards, 

including Energy Star and those imposed by the California Energy Commission (CEC), J.A. 16400 (569:17–

571:20), J.A. 16500–01 (795:9–796:3), J.A. 16523–24 

(887:25–891:10), J.A. 16778 (1435:8–1437:18), J.A. 25065; 

Fairchild competed for business it knew was directed to 

the United States, J.A. 16929 (1871:25–1873:1), J.A. 

16931 (1878:4–1879:8); J.A. 24492, J.A 24495; Fairchild 

provided demonstration boards containing the infringing 

controller chips to customers and potential customers in 

the United States, J.A. 16514 (848:19–849:10), J.A. 16524 

(889:22–890:5), J.A. 16794 (1498:25–1499:3); Fairchild’s 

website enabled customers to locate a United Statesbased distributor that sold Fairchild’s infringing controller chips, J.A. 16927 (1864:1–1866:1); Fairchild maintained a technical support center in the United States 

that provided support for the infringing controller chips to 

customers based in the United States, J.A. 16402 (579:13–

580:6), J.A. 24174; and Fairchild’s standard terms and 

conditions indemnified customers against claims for 

infringement of United States patents, J.A. 16773 

(1416:1–24). 

Case: 15-1329 Document: 87-2 Page: 28 Filed: 12/12/2016
POWER INTEGRATIONS v. FAIRCHILD SEMICONDUCTOR 29

Fairchild endeavors to explain away or otherwise diminish the value of each piece of evidence presented by 

Power Integrations. For instance, Fairchild argues that 

its provision of demonstration boards was “ordinary 

commercial activity” that cannot lead to liability for 

induced infringement because its controller chips have 

non-infringing uses. Appellants’ Opening Br. 25 (citing 

Grokster, 545 U.S. at 937). But, Fairchild ignores that the 

only non-infringing use of its controller chips was foreign 

use. Power Integrations introduced evidence that

Fairchild shipped demonstration boards to customers and 

potential customers in the United States. The jury was 

therefore entitled to consider this evidence in determining 

if Fairchild induced infringement in the United States.

As another example, Fairchild argues that its promotion of its products as compliant with certain energy 

efficiency standards—such as Energy Star and those 

imposed by CEC—that originated in the United States

cannot constitute inducing acts, because the standards

had been adopted by many other countries. Appellants’ 

Opening Br. 29–31. But, the jury heard testimony, including from Fairchild’s own witnesses, that the Energy 

Star and CEC standards are United States standards. 

See, e.g., J.A. 16467 (660:21–25); J.A. 16500 (795:9–23); 

J.A. 16523–24 (887:22–888:1); J.A. 16524 (890:25–891:10). 

The jury also heard testimony that, while other countries 

initially adopted the United States energy efficiency 

standards, certain countries had established different, 

more stringent standards of their own. J.A. 16778 

(1435:3–20). In light of this testimony, it was reasonable 

for a juror to view Fairchild’s promotion of its products as 

Energy Star and/or CEC compliant as targeted to the 

United States market, and therefore relevant to inducement. 

Rather than addressing each of Fairchild’s remaining, 

discrete attacks on Power Integrations’ evidence of inducement, we note that Fairchild misses the forest for the 

Case: 15-1329 Document: 87-2 Page: 29 Filed: 12/12/2016
30 POWER INTEGRATIONS v. FAIRCHILD SEMICONDUCTOR

trees. While each piece of evidence may not individually 

be sufficient to establish Fairchild’s liability, see, e.g., 

MEMC, 420 F.3d at 1378–79 (holding that an indemnity 

provision alone cannot establish intent to induce infringement unless “the primary purpose” of the provision 

was to induce infringement), the evidence as a whole 

provided the jury substantial evidence upon which to find 

inducement by Fairchild, see, e.g., Lucent Techs., Inc. v. 

Gateway, Inc., 580 F.3d 1301, 1323 (Fed. Cir. 2009) (“Having perused the evidence, we agree with [defendant] that 

the evidence is not strong, but we are not persuaded that 

the jury was unreasonable in finding that [defendant]

possessed the requisite intent to induce at least one user 

of its products to infringe the claimed methods.”).

Fairchild offers an alternative theory why it is entitled to JMOL of no induced infringement: Power Integrations failed to establish a nexus between Fairchild’s 

allegedly inducing acts and the acts of direct infringement 

Power Integrations proved at trial. It contends that 

Power Integrations introduced evidence of only three acts 

of direct infringement—sales of an HP printer, Acer 

notebook computer, and Samsung notebook computer 

containing infringing Fairchild controller chips—and that 

Power Integrations was required to present evidence that 

Fairchild specifically induced HP, Acer, Samsung, or the 

retailers from which Power Integrations purchased the 

infringing products to incorporate the infringing controller chips into products bound for the United States. 

Appellants’ Opening Br. 20 (“[Power Integrations] put on 

no evidence of the provenance of the chips in these devices, or that Fairchild induced Best Buy, Wal-Mart, HP, 

Acer, Samsung, or any downstream reseller to incorporate 

accused chips into U.S.-bound products with specific 

intent to bring about these U.S. infringements.”). 

We find this argument without merit. As detailed 

above, Power Integrations presented substantial evidence 

that Fairchild took affirmative acts to induce third parties 

Case: 15-1329 Document: 87-2 Page: 30 Filed: 12/12/2016
POWER INTEGRATIONS v. FAIRCHILD SEMICONDUCTOR 31

to import its controller chips into the United States 

wherein—Fairchild does not seriously dispute—the chips

necessarily infringed. While none of this evidence can be 

directly linked to the particular HP printer, Acer notebook 

computer, or Samsung notebook computer Power Integrations introduced at trial as representative acts of direct 

infringement, it was sufficient to allow the jury to find 

that Fairchild had induced its customers (including HP, 

Acer, and Samsung) to infringe as a class. This is all that 

we require. See Dynacore, 363 F.3d at 1274–75 (contrasting the proof required to prove individual acts of 

induced infringement as opposed to inducement of “an 

entire category of infringers (e.g., the defendant’s customers)”). Indeed, we have affirmed induced infringement

verdicts based on circumstantial evidence of inducement

(e.g., advertisements, user manuals) directed to a class of 

direct infringers (e.g., customers, end users) without 

requiring hard proof that any individual third-party 

direct infringer was actually persuaded to infringe by that 

material. See, e.g., Ericsson, 773 F.3d at 1220, 1222 

(affirming jury’s induced infringement verdict where 

defendant advertised compliance with an infringing 

standard); Arthrocare Corp. v. Smith & Nephew, Inc., 406 

F.3d 1365, 1377 (Fed. Cir. 2005) (affirming jury’s induced 

infringement verdict where defendant distributed “sales 

literature” and “manuals” that instructed how to use 

product in infringing manner); cf. Liquid Dynamics Corp. 

v. Vaughan Co., Inc., 449 F.3d 1209, 1223 (Fed. Cir. 2006) 

(affirming infringement verdict under 35 U.S.C. § 271(f) 

and explaining that distribution of “engineering manual 

. . . replete with examples” of infringing use was substantial evidence of inducement). 

Accordingly, having reviewed the record as a whole, 

we cannot conclude that no reasonable jury—if instructed 

properly—could have found that Fairchild induced infringement of the ’851 and ’876 patents. 

Case: 15-1329 Document: 87-2 Page: 31 Filed: 12/12/2016
32 POWER INTEGRATIONS v. FAIRCHILD SEMICONDUCTOR

II. The ’605 Patent (Current Limiting) 

Fairchild appeals the jury’s verdict that claims 1 and 

2 of the ’605 patent were not anticipated by Maige. Power 

Integrations cross-appeals and argues that it is entitled to 

a new trial on induced infringement due to certain prejudicial statements made by Fairchild during trial. We find 

the jury’s verdict that Maige did not anticipate claims 1 

and 2 of the ’605 patent unsupported by substantial 

evidence. We therefore reverse the jury’s verdict of no 

anticipation. As a result, Power Integrations’ crossappeal is moot.

The ’605 patent claims “[a] power supply regulator including a variable current limit threshold that increases 

during an on time of a switch.” ’605 patent, Abstract. 

Claim 1 reads as follows:

1. A power supply regulator, comprising:

a comparator having a first input coupled 

to sense a voltage representative of a current flowing through a switch during an 

on time of the switch, the comparator having a second input coupled to receive a variable current limit threshold that increases 

during the on time of the switch; 

a feedback circuit coupled to receive a 

feedback signal representative of an output voltage at an output of a power supply; and

a control circuit coupled to generate a control signal in response to an output of the 

comparator and in response to an output 

of the feedback circuit, the control signal 

to be coupled to a control terminal of the 

switch to control switching of the switch.

Id. at 6:10–27 (emphasis added). Claim 2 depends from 

claim 1 and further requires “an oscillator having a first 

Case: 15-1329 Document: 87-2 Page: 32 Filed: 12/12/2016
POWER INTEGRATIONS v. FAIRCHILD SEMICONDUCTOR 33

output to generate a sawtooth waveform, wherein the 

variable current limit threshold is generated in response 

to the sawtooth waveform.” Id. at 6:28–29.

Maige describes “[a] protection device for switch mode 

power supplies.” Maige, Abstract. Like the regulator 

claimed in the ’605 patent, Maige’s protection device uses 

a current limit threshold to protect downstream components in the event of a power surge. The specific type of 

threshold employed by Maige depends on the mode of the 

protection device. When the protection device is in startup mode, Maige uses “soft start circuitry” to introduce an 

increasing current threshold that prevents a large in-rush 

of current. When the protection device is in its normal 

operation mode, Maige uses a fixed current limit.

At trial, the parties disputed whether Maige discloses 

“a variable current limit threshold that increases during 

the on time of the switch.” ’605 patent, 6:11–15. 

Fairchild presented the testimony of its expert, Dr. GuYeon Wei, that Maige’s current threshold increased 

throughout the period of start-up—during which the 

device alternates between on and off states—and thereby 

satisfied the limitation. Power Integrations countered 

with the testimony of its own expert, Dr. Arthur Kelley. 

Dr. Kelley testified that Maige’s current threshold did not 

increase “during the on time of the switch” as required by 

the claim and presented test data in the form of an oscilloscope screen capture to show that the current threshold 

remained constant during start-up. The jury sided with 

Power Integrations and found that Maige did not anticipate claims 1 and 2 of the ’605 patent.

We find that the jury’s verdict is not supported by 

substantial evidence. Dr. Kelley testified at trial that 

(1) Maige’s current threshold increases “[d]uring the 

whole process of startup,” J.A. 16907 (1785:4–14); and 

(2) Maige’s power supply is on “for some period of time” 

during startup, J.A. 16908 (1786:22–1787:4). Taken 

together, Dr. Kelley’s testimony is a concession that 

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34 POWER INTEGRATIONS v. FAIRCHILD SEMICONDUCTOR

Maige’s current threshold “increases during the on time of 

the switch.”

This is all that claims 1 and 2 require. Nothing in the 

claims requires that the current threshold increase during 

the power supply’s normal operation. Indeed, Dr. Kelley 

testified to this effect at trial:

Q. Okay. So you would agree with me, I hope, 

that there is nothing in Claim 1 that limits the 

operation to what is claimed here to normal conditions only. Right?

A. Sure. 

J.A. 16980 (1786:18–21). Therefore, that Maige’s current 

threshold only increases during start-up mode—not 

normal operation—is irrelevant to the analysis. See 

Unwired Planet, LLC v. Google Inc., --- F.3d ---, 2016 WL 

6694955, at *5 (Fed. Cir. Nov. 15, 2016) (“[C]ombinations 

of prior art that sometimes meet the claim elements are 

sufficient to show obviousness.”); see also Hewlett-Packard 

Co. v. Mustek Sys., Inc., 340 F.3d 1314, 1326 (Fed. Cir. 

2003) (“Just as ‘an accused product that sometimes, but 

not always, embodies a claimed method nonetheless 

infringes,’ a prior art product that sometimes, but not 

always, embodies a claimed method nonetheless teaches 

that aspect of the invention.” (quoting Bell Commc’ns 

Research, Inc. v. Vitalink Commc’ns Corp., 55 F.3d 615, 

622–623 (Fed. Cir. 1995)). 

Equally irrelevant is the oscilloscope screen capture 

presented at trial by Dr. Kelley:

Case: 15-1329 Document: 87-2 Page: 34 Filed: 12/12/2016
POWER INTEGRATIONS v. FAIRCHILD SEMICONDUCTOR 35

Appellee’s Opening Br. 57. The screen capture purports 

to show that the current threshold (shown in dark blue) 

remains constant during the power supply’s on time 

(represented by the two higher portions of the light-blue 

waveform). But the screen capture is limited to a

100 μsec18 window of operation. It is not surprising that 

the current threshold did not measurably increase during 

this time. By Dr. Kelley’s own admission, the current 

threshold increases over the full one-second start-up 

period. See J.A. 16980 (1787:20–25). As such, the current 

threshold would increase only 1/10,000th of its full range 

over the course of the entire screen capture. It is not 

surprising that such a small increase is not visible to the 

human eye considering the 2-volt-per-division scaling 

used in the screen capture. 

All that matters for anticipation is that Maige disclose 

“a variable current limit threshold that increases during 

the on time of the switch.” Power Integrations’ expert, 

Dr. Kelley, admitted that it does. The jury therefore 

 

18 1 μsec (also known as 1 microsecond) is 0.000001 

seconds. 100 μsec is equal to 0.0001 seconds.

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36 POWER INTEGRATIONS v. FAIRCHILD SEMICONDUCTOR

lacked substantial evidence to find that Maige did not 

anticipate claims 1 and 2 of the ’605 patent.

III. The ’972 Patent (Primary-Side Control) 

The jury found that claims 6, 7, 18, and 19 were not 

invalid. It further found that Power Integrations infringed the claims under the doctrine of equivalents, but 

did not infringe literally and did not induce others to 

infringe. Fairchild appeals the jury’s verdict that Power 

Integrations did not induce infringement of the asserted

claims. Power Integrations cross-appeals and raises the 

following arguments: (1) the district court improperly 

construed the claim limitation “sampling a voltage from 

the auxiliary winding of the transformer and a discharge 

time of the transformer;” (2) the jury’s verdict that the 

claims would not have been obvious in view of Majid in 

combination with the ’876 patent is not supported by 

substantial evidence; and (3) the jury’s verdicts that 

Power Integrations did not literally infringe the claims 

but did infringe under the doctrine of equivalents result 

in claim vitiation.

We affirm the district court’s claim construction and 

the jury’s verdict that claims 6, 7, 18, and 19 would not 

have been obvious. We agree with Power Integrations 

that the jury’s infringement verdicts vitiate the requirement that the claimed feedback signals be “distinct.” We 

therefore reverse the jury’s verdict that Power Integrations infringed claims 6, 7, 18, and 19 under the doctrine 

of equivalents. In view of these decisions, Fairchild’s 

appeal is moot.

A. Claim Construction

The ’972 patent claims a power supply that includes 

frequency jittering and primary-side feedback to prevent 

overcurrent. ’972 patent, 1:9–12. Fairchild asserted 

claims 6, 7, 18, and 19 of the patent against Power Integrations. Claim 6 depends from claim 1. Claim 1 reads 

as follows:

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POWER INTEGRATIONS v. FAIRCHILD SEMICONDUCTOR 37

1. A power converter comprising:

a switch, responsive to a switching signal, 

to control electrical power in the power 

converter; and

a controller to generate the switching signal and to control the switching signal in 

response to a first feedback signal associated with a voltage control loop and a second feedback signal associated with a 

current control loop;

wherein the controller includes a pattern 

generator to generate a digital pattern 

and the controller uses the digital pattern 

for use in generating the switching signal 

as a frequency-hopping switching signal to 

the switch.

Id. at 15:22–49. Claim 619 further requires “wherein the 

controller generates the first feedback signal by sampling 

a voltage from the auxiliary winding of the transformer 

and a discharge time of the transformer.” Id. at 15:50–53

(emphasis added). Claim 7 depends from claim 6 and 

further limits independent claim 1’s “second feedback 

signal.” It is not relevant to the parties’ claim construction dispute. Claims 18 and 19 depend from claim 15 and 

are analogous to claims 6 and 7, but in method form.

The parties dispute the construction of the limitation 

“sampling a voltage from the auxiliary winding of the 

transformer and a discharge time of the transformer.” 

The district court adopted Fairchild’s proposed construction: “sampling a voltage from the auxiliary winding of 

the transformer when the transformer is discharging.” 

 

19 Claim 6 depends from claim 1 by way of claims 2 

and 5. None of the limitations added in claims 2 or 5 are 

relevant to this issue.

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Claim Construction Order, 2009 WL 4928029, at *25. 

Power Integrations contends that the district court’s 

construction departs from the plain and ordinary meaning 

of the claims, which it claims requires sampling both a 

voltage and a discharge time.

“[T]he words of a claim ‘are generally given their ordinary and customary meaning.’” Phillips v. AWH Corp., 

415 F.3d 1303, 1312 (Fed. Cir. 2005) (en banc) (quoting 

Vitronics Corp. v. Conceptronic, Inc., 90 F.3d 1576, 1582 

(Fed. Cir. 1996)). The “ordinary and customary meaning” 

is “the meaning that the term would have to a person of 

ordinary skill in the art in question at the time of the 

invention.” Id. at 1313. “Properly viewed, the ‘ordinary 

meaning’ of a claim term is its meaning to the ordinary 

artisan after reading the entire patent.” Id. at 1321.

We disagree with Power Integrations that the limitation at issue is clear on its face. See Appellee’s Opening 

Br. 25 (“The claims’ ordinary meaning could not be clearer.”). Specifically, it is ambiguous what clauses are linked 

by the conjunction “and.” The limitation could be construed to require that the controller sample (1) “a voltage 

from the auxiliary winding of the transformer,” and (2) “a 

discharge time of the transformer,” as Power Integrations 

argues. Alternatively, the limitation could be construed

to require that the controller sample a voltage from 

(1) “the auxiliary winding of the transformer,” and (2) “a 

discharge time of the transformer.” In this alternative 

construction, the limitation defines both where the voltage is sampled (i.e., the auxiliary winding of the transformer) and when the voltage is sampled (i.e., during the 

discharge time of the transformer). The district court 

adopted this latter construction.

While the limitation is ambiguous in isolation, we find 

its meaning clear when viewed in the context of the 

patent specification. Phillips, 415 F.3d at 1313 (“Importantly, the person of ordinary skill in the art is deemed 

to read the claim term not only in the context of the 

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POWER INTEGRATIONS v. FAIRCHILD SEMICONDUCTOR 39

particular claim in which the disputed term appears, but 

in the context of the entire patent, including the specification.”).

The specification explains that, when the power supply’s switch is turned off, electrical energy stored in the 

power supply’s transformer flows from the primary side of 

the transformer to the secondary, or auxiliary, side of the 

transformer. ’972 patent, 3:36–42. It is during this 

“discharge time” that voltage is generated at the auxiliary 

winding of the transformer. Id. at 3:56–58. The specification later explains that the power supply’s controller 

samples this voltage (VAUX) during the discharge time. 

See id. at 7:48–51; id. at 8:49–9:30. The power supply 

uses the sampled voltage as a mechanism to generate the 

first feedback signal. See id. at 4:29–42 (describing how 

VAUX is used to generate detector voltage VDET); id. at 5:1–

16 (describing how VDET is used to generate feedback VV). 

The patent specification’s description is thus consistent 

with the district court’s construction that “sampling a 

voltage from the auxiliary winding of the transformer and 

a discharge time of the transformer” means “sampling a 

voltage from the auxiliary winding of the transformer 

when the transformer is discharging.”

Power Integrations’ argument that the district court’s 

construction “create[s] problems for the analogous language in unasserted claims 8 and 20” does not change this 

result. Appellee’s Opening Br. 27. Claims 8 and 20 

depend from asserted claims 7 and 19, respectively, and 

require “generating the second feedback signal by sampling of sensed current and the discharge time of the 

transformer.” ’972 patent 16:58–61; see also id. at 15:58–

61 (“generat[ing] the second feedback signal by sampling 

of the sensed current from the sense circuit and the 

discharge time of the transformer”). Power Integrations 

contends that replacing “and” with “when”—its characterization of the district court’s construction of claims 6 and 

18—would require that the sensed current be sampled 

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from the sensed circuit when the transformer is discharging, an impossibility because the sensed current does not 

exist when the transformer is discharging. Appellee’s 

Opening Br. 27–28. 

Power Integrations’ argument is based on a faulty 

premise. The district court was not asked to construe the 

word “and” in claims 6 and 18. And, it did not do so. 

Rather, it construed the entire claim term “sampling a 

voltage from the auxiliary winding of the transformer and 

a discharge time of the transformer.” One cannot assume 

that an individual portion of the district court’s construction can be imported into claims 8 and 20 simply because 

those claims use similar language. Similar language in 

different claims may be construed differently based on the 

context in which it is used and other intrinsic evidence. 

See Wilson Sporting Goods Co. v. Hillerich & Bradsby Co., 

442 F.3d 1322, 1328 (Fed. Cir. 2006) (“Under this court’s 

case law, the same terms appearing in different claims in 

the same patent—e.g. ‘gap’ in claims 1 and 15—should 

have the same meaning ‘unless it is clear from the specification and prosecution history that the terms have different meanings at different portions of the claims.’ In this 

case, the claims use the term ‘gap,’ but then modify it 

differently to suggest differences in the geometry of the 

‘gap’ in the various claims.” (citation omitted)).

We therefore affirm the district court’s construction.

B. Validity

Power Integrations argues that claims 6, 7, 18, and 19 

of the ’972 patent would have been obvious in view of 

Majid and the ’876 patent. The jury rejected this argument at trial. We affirm the jury’s verdict. 

Majid describes a switched-mode power supply that 

uses feedback to control output voltage, thereby preventing damage to downstream components. See Majid, 

Abstract. The ’876 patent—described above, supra at 7–

8—claims a circuit that introduces “jitter” to a power 

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POWER INTEGRATIONS v. FAIRCHILD SEMICONDUCTOR 41

supply’s oscillator frequency to reduce the amount of EMI 

generated by the power supply. ’876 patent, 1:66–67. 

Power Integrations contends a combination of these two 

references discloses every limitation of claims 6, 7, 18, 

and 19 of the ’972 patent. It further contends that combining the features disclosed in the references would have 

been easy for one of ordinary skill in the art, thereby 

rendering the claims obvious. Fairchild counters that the 

asserted claims would not have been obvious for two 

reasons. First, it argues that Majid does not disclose the 

specific second feedback signal claimed in the ’972 patent. 

Second, it argues that one of ordinary skill in the art 

would have experienced great difficulty in combining 

Majid with the ’876 patent.

At trial, the parties supported their arguments with 

the testimony of their respective experts, Dr. Kelley for 

Power Integrations and Dr. Wei for Fairchild. Each 

expert testified in rather conclusory fashion. With little 

explanation, Dr. Kelley highlighted the portions of Majid 

and the ’876 patent that he believed disclosed the different claim limitations. J.A. 17048 (2171:14–2174:19). The 

focus of his testimony was whether it would have been 

difficult for a skilled artisan to combine frequency jitter 

(i.e., the ’876 patent) with primary-side control (i.e., 

Majid); he concluded that it would not have been. 

J.A. 17048–49 (2174:20–2178:8). Dr. Wei, likewise with 

little explanation, testified that Majid did not disclose the 

“second feedback signal” claimed in the ’972 patent and 

that it would have been difficult to combine frequency 

jitter with primary-side control. J.A. 17057–58 (2208:3–

2211:20).

Each expert’s credibility was called into question during cross-examination. Counsel for Fairchild raised an 

apparent inconsistency between Dr. Kelley’s expert report

on non-infringement and his testimony on invalidity. In 

opining that Power Integrations did not infringe the ’972 

patent, Dr. Kelley stated that the current output of a

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42 POWER INTEGRATIONS v. FAIRCHILD SEMICONDUCTOR

conventional current limit circuit—like that supposedly 

employed by Power Integrations—did not satisfy the 

“second feedback signal” required by the claims. 

J.A. 17055–56 (2200:12–2203:8). Yet, in testifying that 

the claims would have been obvious, Dr. Kelley testified 

that Majid’s conventional current limit circuit did satisfy 

the “second feedback signal” limitation of the claims. 

J.A. 17055 (2200:3–11).

Counsel for Power Integrations similarly exposed an 

apparent inconsistency between Dr. Wei’s trial testimony 

and his testimony during deposition. At trial, Dr. Wei 

testified that Majid did not disclose the “second feedback 

signal” limitation. J.A. 17057 (2208:24–2209:7). But,

during deposition, Dr. Wei testified that the combination 

of Majid and the ’876 patent disclosed all claim limitations. J.A. 17061–62 (2226:19–2227:9).

“When reviewing a denial of judgment as a matter of 

law of obviousness, where there is a black box jury verdict, as is the case here, we presume the jury resolved 

underlying factual disputes in favor of the verdict winner 

and leave those presumed findings undisturbed if supported by substantial evidence.” WBIP, LLC v. Kohler 

Co., 829 F.3d 1317, 1326 (Fed. Cir. 2016). Dr. Wei’s 

testimony provided the jury with substantial evidence for 

its presumed findings that Majid did not disclose the 

“second feedback signal” limitation of claims 6, 7, 18, and 

19 and that a skilled artisan would have had difficulty 

combining frequency jitter with primary-side control. 

While Dr. Kelley testified to the contrary, “when there is 

conflicting testimony at trial, and the evidence overall 

does not make only one finding on the point reasonable, 

the jury is permitted to make credibility determinations 

and believe the witness it considers more trustworthy.” 

MobileMedia Ideas LLC v. Apple Inc., 780 F.3d 1159, 1168 

(Fed. Cir. 2015) (citation omitted). “Where there is substantial evidence for a reasonable jury finding, it is not 

our function to second guess or reevaluate the weight 

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POWER INTEGRATIONS v. FAIRCHILD SEMICONDUCTOR 43

given to that evidence.” Id. This is particularly true here, 

where it was Power Integrations’ burden to prove by clear 

and convincing evidence that the claims were invalid.

We therefore find the jury’s verdict that claims 6, 7, 

18, and 19 would not have been obvious in view of Majid 

and the ’876 patent supported by substantial evidence. 

C. Doctrine of Equivalents

Claims 6 and 7 of the ’972 patent depend from claim 

1, which includes the following limitation:

a controller to generate the switching signal and 

to control the switching signal in response to a 

first feedback signal associated with a voltage 

control loop and a second feedback signal associated with a current control loop . . . .

’972 patent, 15:25–29. Claims 18 and 19 depend from 

claim 15, which includes an equivalent limitation. Id. at 

16:36–40. The district court construed this limitation to 

require that the claimed second feedback signal be “distinct from the first feedback signal.” Claim Construction 

Order, 2009 WL 4928029, at *12. Neither party appeals 

this construction. 

The patent’s Figure 3 graphically depicts the claimed 

voltage control loop and current control loop and their 

respective first and second feedback signals. 

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claimed two “distinct” feedback signals would vitiate the 

“distinct”-ness required by the claims. Pursuant to this 

understanding, Power Integrations argues that it is 

entitled to JMOL of no infringement.

In response, Fairchild first argues that Power Integrations’ invocation of claim vitiation is misplaced. It 

states that Power Integrations presented two, separate 

non-infringement theories at trial: first, that the two 

feedback signals Fairchild’s expert, Dr. Wei, identified 

were not “distinct;” and second, that the current signal 

Dr. Wei identified as the claimed “second feedback signal” 

was not actually a “feedback signal.” It contends that 

only Power Integrations’ first theory could conceivably 

result in claim vitiation and argues that we should not 

assume the jury relied on this theory when it could have, 

just as easily, relied on Power Integrations’ alternate 

theory. The district court adopted Fairchild’s reasoning 

in denying Power Integrations’ motion for JMOL of no 

infringement under the doctrine of equivalents. JMOL 

Decision, 935 F. Supp. 2d at 754.

We disagree with Fairchild and the district court. 

Power Integrations’ expert, Dr. Kelley, presented a single 

non-infringement theory at trial, namely, that Power 

Integrations’ products include only a single feedback 

signal. See, e.g., J.A. 17041 (2145:11–14) (Dr. Kelley: “It 

uses just a single feedback signal that arrives at one pin 

that is indicative of the output voltage, and that is used to 

regulate the output voltage, but it does not have any kind 

of current feedback signal.”); J.A. 17043 (2151:23–2152:2) 

(Dr. Kelley testifying that the LinkSwitch-II does not 

have two feedback signals). When Dr. Kelley testified 

that the output of the LinkSwitch-II’s constant current 

block (i.e., “I REDUCE”) was not a “feedback signal,” he 

did not introduce a new non-infringement theory. Rather, 

he made clear that the output was not a “feedback signal”

because the LinkSwitch-II used only a single feedback 

signal (i.e., “FEEDBACK (FB)”): 

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POWER INTEGRATIONS v. FAIRCHILD SEMICONDUCTOR 47

Q. Okay. Focusing on the constant current block, 

is the output of the constant current block a second feedback signal associated with a current control loop? 

A. No, it’s not.

Q. Why not?

A. There’s no current input, the constant current 

block. All it has as an input is the same voltage 

feedback signal that’s used elsewhere. 

J.A. 17043 (2152:18–25) (emphasis added). As such, the 

jury necessarily found that the LinkSwitch-II products 

contain a single feedback signal when it rendered its 

verdict of no literal infringement. 

We must therefore weigh the merits of Power Integrations’ claim vitiation argument. Under claim vitiation, “if 

a court determines that a finding of infringement under 

the doctrine of equivalents would entirely vitiate a particular claimed element, then the court should rule that 

there is no infringement under the doctrine of equivalents.” Lockheed Martin Corp. v. Space Systems/Loral, 

Inc., 324 F.3d 1308, 1321 (Fed. Cir. 2003) (internal quotation marks, alternations, and citation omitted); see also 

Warner-Jenkinson Co., Inc. v. Hilton Davis Chem. Co., 

520 U.S. 17, 40 (1997) (“[I]f a theory of equivalence would 

entirely vitiate a particular claim element, partial or 

complete judgment should be rendered by the court.”). 

We agree with Power Integrations that a finding of infringement under the doctrine of equivalents would 

vitiate the requirement that the claimed feedback signals 

be “distinct.” The inventor of the ’972 patent detailed at 

trial the difficulty he and his team had in designing a 

power supply with accurate primary-side control and the 

breakthrough he achieved by adding a second feedback 

signal specifically related to output current. J.A. 16917 

(1822:8–1824:24). He went on to testify that having a 

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second feedback signal—related to current—that is distinct from the first feedback signal—related to voltage—is 

what distinguished the claimed invention from the prior 

art. J.A. 16924 (1851:15–1852:11).

Here, the jury implicitly found that Power Integrations’ LinkSwitch-II products contain a single feedback 

signal, not two “distinct” feedback signals as required by 

the claims. “[N]ot using two distinct signals to control 

voltage and current can’t be equivalent to using distinct 

signals—the signals are either distinct or they aren’t.” 

Appellee’s Opening Br. 29. A finding to the contrary 

would render the requirement that the feedback signals 

be “distinct”—the feature described by the inventor as 

critical to the invention’s novelty—meaningless. See Am. 

Calcar, Inc. v. Am. Honda Motor Co., 651 F.3d 1318, 1339 

(Fed. Cir. 2011) (rejecting plaintiff’s doctrine of equivalents theory and reasoning that “finding a signal from one 

source to be equivalent to ‘signals from a plurality of 

sources’ would vitiate that claim limitation by rendering 

it meaningless”).

We therefore reverse the jury’s verdict that Power Integrations infringed claims 6, 7, 18, and 19 under the 

doctrine of equivalents.

IV. Permanent Injunction

Following trial, the district court granted Power Integrations’ motion for a permanent injunction and enjoined 

“Fairchild from selling, offering to sell, and importing the 

products found at trial to infringe and those products ‘not 

colorably different’ from them.” Permanent Injunction 

Order, 2014 WL 2960035, at *2. The district court denied 

Fairchild’s motion for a permanent injunction. Fairchild 

appeals both of these rulings.

We first note that Fairchild’s appeal of the district 

court’s denial of Fairchild’s motion for a permanent 

injunction is moot. The district court entered judgment of 

infringement against Power Integrations on the ’972 

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POWER INTEGRATIONS v. FAIRCHILD SEMICONDUCTOR 49

patent alone. We have reversed that judgment. See 

supra at 43–48. Without a judgment of infringement by 

Power Integrations, issuance of a permanent injunction is 

not appropriate.

Turning to the district court’s grant of Power Integrations’ motion for a permanent injunction, we vacate that 

decision. We have significantly reduced the scope of 

Fairchild’s infringement liability in this case. As a result 

of our above holdings, only the district court’s judgment 

that Fairchild is liable for direct infringement of the ’851 

and ’876 patents remains untouched. We leave it to the 

district court to determine in the first instance if a permanent injunction is appropriate in view of Fairchild’s 

infringement liability. Though, we recognize that the 

district court may exercise its discretion and defer its 

decision until Power Integrations’ claims that Fairchild 

induced infringement of the ’851 and ’876 patent are 

resolved. 

CONCLUSION

For the preceding reasons, we affirm-in-part, reversein-part, and vacate-in-part the final judgment entered by 

the district court and remand for further proceedings.

AFFIRMED-IN-PART, REVERSED-IN-PART, 

VACATED-IN-PART, AND REMANDED

COSTS

Each party shall bear its own costs.

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