Power Integrations, Inc. v. Fairchild Semiconductor International, Inc. ( 2016 )


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  •   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
    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 Semicon-
    ductor International, Inc., Fairchild Semiconductor Cor-
    poration, 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 direct-
    ly infringed the ’605 patent, but denied the parties’ other
    JMOL motions and motions for a new trial. Power Inte-
    grations, 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) (Perma-
    nent 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
    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 cross-
    appeals 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 Martin 2 or
    Wang 3 is affirmed.
    •   Because the district court’s jury instruction incor-
    rectly stated the law on inducement, the jury’s ver-
    dict that Fairchild induced infringement of the
    asserted claims of the ’876 and ’851 patents is va-
    cated.
    •   The jury’s verdict that the asserted claims of the
    ’605 patent were not anticipated by Maige 4 is re-
    versed.
    •   The district court’s construction that the asserted
    claims of the ’972 patent require “sampling a volt-
    age 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, Pro-
    grammed Pulsewidth Modulated Waveforms for Electro-
    magnetic 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
    .
    4          POWER INTEGRATIONS   v. FAIRCHILD SEMICONDUCTOR
    •   The jury’s verdict that the asserted claims of the
    ’972 patent would not have been obvious in view of
    Majid 5 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 vacate-
    in-part the final judgment entered by the district court
    and remand for further proceedings.
    BACKGROUND
    Power Integrations and Fairchild are direct competi-
    tors 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 Delaware 6 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 Semicon-
    ductor Int’l, Inc., No. 1:08-cv-00309-LPS (D. Del. filed May
    23, 2008); Power Integrations, Inc. v. Fairchild Semicon-
    ductor Int’l, Inc., No. 1:04-cv-01371-LPS (D. Del. filed Oct.
    20, 2004).
    7   See Power Integrations, Inc. v. Fairchild Semicon-
    ductor Int’l, Inc., No. 3:09-cv-05235-MMC (N.D. Cal. filed
    Nov. 4, 2009).
    POWER INTEGRATIONS   v. FAIRCHILD SEMICONDUCTOR          5
    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 Semi-
    conductor Int’l, Inc., 
    711 F.3d 1348
     (Fed. Cir. 2013) (re-
    viewing jury verdict on ’851 and ’876 patents, among
    others).
    Power supplies are ubiquitous in modern society. An-
    yone 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. Some-
    where 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 Semicon-
    ductor 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).
    6         POWER INTEGRATIONS   v. FAIRCHILD SEMICONDUCTOR
    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 convert-
    ing the power supplied by the wall outlet into a form the
    electronic device can use. The power a wall outlet pro-
    vides 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 high-
    voltage AC power. Power supplies convert the high-
    voltage AC power supplied by the wall outlet into the low-
    voltage 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.
    POWER INTEGRATIONS   v. FAIRCHILD SEMICONDUCTOR           7
    states through the use of an oscillator. Prior art switch-
    mode 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 frequen-
    cy—using a step function like the one shown above or
    some other scheme—the power supply divides any EMI it
    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 cur-
    rent 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
    10        POWER INTEGRATIONS   v. FAIRCHILD SEMICONDUCTOR
    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 “second-
    ary side” of the power supply. See id. at 2:64–66. Power
    supplies use a transformer to isolate the input terminals
    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 in-
    creased the size and cost of the power supply. Id.
    The power supply claimed in the ’972 patent, in con-
    trast, 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 Integra-
    tions directly and indirectly infringed the ’972 and ’595
    patents and 
    U.S. Patent No. 7,061,780
    . Each party de-
    nied 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
    12        POWER INTEGRATIONS    v. FAIRCHILD SEMICONDUCTOR
    liability commenced on April 11, 2012. 10 At the conclu-
    sion 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 as-
    serted 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 in-
    fringe 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 literal-
    ly, under the doctrine of equivalents, or by inducement.
    10 By the time of trial, the ’780 patent was no longer
    at issue.
    POWER INTEGRATIONS   v. FAIRCHILD SEMICONDUCTOR           13
    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 liabil-
    ity on January 13, 2015. Fairchild filed a timely appeal
    and Power Integrations cross-appealed. We have jurisdic-
    tion 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) chal-
    lenges to the district court’s denial of certain of the par-
    ties’ 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 Pharma-
    ceuticals 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.
    14         POWER INTEGRATIONS    v. FAIRCHILD SEMICONDUCTOR
    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. D-
    Link 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 Cir-
    cuit exercises plenary review of a denial of JMOL, apply-
    ing 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 con-
    clusion(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
    the deferential ‘abuse of discretion’ standard to the rul-
    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 conclu-
    sions 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 in-
    fringement 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, howev-
    er, 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 antici-
    pated claims 1 and 21 of the ’876 patent. The ’876 patent
    claims a “frequency jittering” circuit used in switched-
    mode 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.
    16         POWER INTEGRATIONS   v. FAIRCHILD SEMICONDUCTOR
    1. A digital frequency jittering circuit for varying
    the switching frequency of a power supply, com-
    prising:
    an oscillator for generating a signal hav-
    ing 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 oscil-
    lator 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., Mar-
    tin, 1:53–55. The below figure from Martin is exemplary:
    POWER INTEGRATIONS   v. FAIRCHILD SEMICONDUCTOR           17
    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 frequen-
    cy that varies according to the pseudo-random code stored
    in EPROM 11.
    At trial, Power Integrations disputed Fairchild’s ar-
    gument 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 sub-
    stantial 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.,
    18        POWER INTEGRATIONS   v. FAIRCHILD SEMICONDUCTOR
    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 calcu-
    lated) must be a target frequency (i.e., b = a).
    While Fairchild’s argument is creative, it fails to ac-
    count 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 specifica-
    tion “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.
    POWER INTEGRATIONS   v. FAIRCHILD SEMICONDUCTOR          19
    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-to-
    analog 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 equiva-
    lents; 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.
    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 infringe-
    ment in the United States. Alternatively, Fairchild
    argues that the verdict should be vacated because the jury
    was improperly instructed that Fairchild need not suc-
    cessfully 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 cus-
    tomers 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)
    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 Dela-
    ware. 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 in-
    fringement by actively inducing others to directly
    infringe the patents in suit. The direct infringe-
    ment may either be literal or under the doctrine of
    equivalents. A party induces patent infringement
    if it purposefully causes, urges, or encourages an-
    other 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 ev-
    idence 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))).
    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 ac-
    tions 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 con-
    firming that belief; and
    3. use by others of the party’s product in-
    fringes one or more of the asserted
    claims of the patent.
    In order to establish active inducement of in-
    fringement, 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. How-
    ever, 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 en-
    couragement succeeded, or was even received.
    Intent to encourage or assist the acts that consti-
    tute direct infringement must be proven by evi-
    dence of active steps taken to encourage direct
    infringement, such as providing products, adver-
    tising any infringing use, or instructing how to
    engage in any use that is infringing.
    POWER INTEGRATIONS   v. FAIRCHILD SEMICONDUCTOR           23
    Proof of intent to induce infringement may be
    based on circumstantial evidence, rather than di-
    rect evidence.
    J.A. 510–11 (emphasis added).
    This instruction left the jury with the incorrect under-
    standing that a party may be liable for induced infringe-
    ment 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 Appli-
    ances, Inc. v. SEB S.A., 
    563 U.S. 754
    , 760 (2011) (altera-
    tion 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).
    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 al-
    leged 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 infringe-
    ment 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 in-
    struction—and, by extension, the jury verdict—by claim-
    ing 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 Grokster 16 and our
    16 Metro-Goldwyn-Mayer Studios Inc. v. Grokster,
    Ltd., 
    545 U.S. 913
     (2005).
    POWER INTEGRATIONS   v. FAIRCHILD SEMICONDUCTOR            25
    decision in Ricoh 17 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] infringe-
    ment 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 mis-
    stated 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 ju-
    ry 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).
    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 im-
    proper—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 reason-
    able 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.” (em-
    phasis 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.” Astor-
    net 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 constitut-
    ed infringement.
    Fairchild does not seriously dispute that Power Inte-
    grations 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 con-
    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 com-
    puter 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 third-
    party 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.” Appel-
    lants’ 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 substan-
    tial 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 sub-
    stantial evidence supports the jury’s verdict that Fairchild
    actually induced third-party direct infringement.
    Fairchild explains that it sells its controller chips over-
    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 encour-
    age 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 signifi-
    cant—though not necessarily overwhelming—evidence
    that would allow a jury to find that Fairchild took affirm-
    ative 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 Califor-
    nia 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 States-
    based distributor that sold Fairchild’s infringing control-
    ler chips, J.A. 16927 (1864:1–1866:1); Fairchild main-
    tained 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).
    POWER INTEGRATIONS   v. FAIRCHILD SEMICONDUCTOR          29
    Fairchild endeavors to explain away or otherwise di-
    minish 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 promo-
    tion 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, in-
    cluding 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 induce-
    ment.
    Rather than addressing each of Fairchild’s remaining,
    discrete attacks on Power Integrations’ evidence of in-
    ducement, we note that Fairchild misses the forest for the
    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 in-
    fringement 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) (“Hav-
    ing 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 enti-
    tled to JMOL of no induced infringement: Power Integra-
    tions 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 control-
    ler 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 devic-
    es, 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
    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 Integra-
    tions 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 (con-
    trasting 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 custom-
    ers)”). 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 substan-
    tial 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 in-
    fringement of the ’851 and ’876 patents.
    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 preju-
    dicial 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’ cross-
    appeal is moot.
    The ’605 patent claims “[a] power supply regulator in-
    cluding 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 cur-
    rent flowing through a switch during an
    on time of the switch, the comparator hav-
    ing a second input coupled to receive a var-
    iable current limit threshold that increases
    during the on time of the switch;
    a feedback circuit coupled to receive a
    feedback signal representative of an out-
    put voltage at an output of a power sup-
    ply; and
    a control circuit coupled to generate a con-
    trol 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
    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 compo-
    nents 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 start-
    up 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. Gu-
    Yeon 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 oscil-
    loscope 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 antici-
    pate 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
    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 condi-
    tions 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:
    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 µsec 18 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.
    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 in-
    fringed 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 require-
    ment that the claimed feedback signals be “distinct.” We
    therefore reverse the jury’s verdict that Power Integra-
    tions 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 Inte-
    grations. Claim 6 depends from claim 1. Claim 1 reads
    as follows:
    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 sig-
    nal and to control the switching signal in
    response to a first feedback signal associ-
    ated with a voltage control loop and a sec-
    ond 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 6 19 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 construc-
    tion 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 construc-
    tion: “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.
    38        POWER INTEGRATIONS   v. FAIRCHILD SEMICONDUCTOR
    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 or-
    dinary 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 limita-
    tion at issue is clear on its face. See Appellee’s Opening
    Br. 25 (“The claims’ ordinary meaning could not be clear-
    er.”). Specifically, it is ambiguous what clauses are linked
    by the conjunction “and.” The limitation could be con-
    strued 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 volt-
    age is sampled (i.e., the auxiliary winding of the trans-
    former) 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 (“Im-
    portantly, the person of ordinary skill in the art is deemed
    to read the claim term not only in the context of the
    POWER INTEGRATIONS   v. FAIRCHILD SEMICONDUCTOR           39
    particular claim in which the disputed term appears, but
    in the context of the entire patent, including the specifica-
    tion.”).
    The specification explains that, when the power sup-
    ply’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 specifica-
    tion 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 lan-
    guage 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 sam-
    pling 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 character-
    ization of the district court’s construction of claims 6 and
    18—would require that the sensed current be sampled
    40         POWER INTEGRATIONS   v. FAIRCHILD SEMICONDUCTOR
    from the sensed circuit when the transformer is discharg-
    ing, 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 construc-
    tion 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 specifi-
    cation and prosecution history that the terms have differ-
    ent 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 argu-
    ment at trial. We affirm the jury’s verdict.
    Majid describes a switched-mode power supply that
    uses feedback to control output voltage, thereby prevent-
    ing 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
    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 com-
    bining 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 differ-
    ent 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 dur-
    ing 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
    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 limita-
    tions. 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 ver-
    dict, 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 sup-
    ported 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 sub-
    stantial evidence for a reasonable jury finding, it is not
    our function to second guess or reevaluate the weight
    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 associ-
    ated 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 “dis-
    tinct 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.
    46        POWER INTEGRATIONS    v. FAIRCHILD SEMICONDUCTOR
    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 Inte-
    grations’ 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)”):
    POWER INTEGRATIONS    v. FAIRCHILD SEMICONDUCTOR         47
    Q. Okay. Focusing on the constant current block,
    is the output of the constant current block a sec-
    ond feedback signal associated with a current con-
    trol 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 Integra-
    tions’ claim vitiation argument. Under claim vitiation, “if
    a court determines that a finding of infringement under
    the doctrine of equivalents would entirely vitiate a partic-
    ular claimed element, then the court should rule that
    there is no infringement under the doctrine of equiva-
    lents.” Lockheed Martin Corp. v. Space Systems/Loral,
    Inc., 
    324 F.3d 1308
    , 1321 (Fed. Cir. 2003) (internal quota-
    tion 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 in-
    fringement 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
    48        POWER INTEGRATIONS   v. FAIRCHILD SEMICONDUCTOR
    second feedback signal—related to current—that is dis-
    tinct 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 Integra-
    tions’ 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 equiva-
    lents 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 In-
    tegrations infringed claims 6, 7, 18, and 19 under the
    doctrine of equivalents.
    IV. Permanent Injunction
    Following trial, the district court granted Power Inte-
    grations’ 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
    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 Integra-
    tions’ 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 per-
    manent 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, reverse-
    in-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.
    

Document Info

Docket Number: 2015-1329; 2015-1388

Judges: Prost, Schall, Chen

Filed Date: 12/12/2016

Precedential Status: Precedential

Modified Date: 3/2/2024

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