Court Opinion

ID: 4255957
Source: CourtListenerOpinion
Date Created: 2018-03-19 16:00:39.763303+00
Date Added: 2024-06-11T07:49:19.333915
License: Public Domain

United States Court of Appeals
      for the Federal Circuit
                 ______________________

       IN RE: POWER INTEGRATIONS, INC.,
                      Appellant
               ______________________

                       2017-1304
                 ______________________

    Appeal from the United States Patent and Trademark
Office, Patent Trial and Appeal Board in No. 90/008,326.
                  ______________________

                Decided: March 19, 2018
                 ______________________

   HOWARD G. POLLACK, Fish & Richardson, PC, Red-
wood City, CA, argued for appellant. Also represented by
MICHAEL R. HEADLEY, NEIL WARREN; CRAIG E.
COUNTRYMAN, San Diego, CA; FRANK SCHERKENBACH,
Boston, MA.

   AMY J. NELSON, Office of the Solicitor, United States
Patent and Trademark Office, Alexandria, VA, argued for
appellee Andrei Iancu. Also represented by NATHAN K.
KELLEY, THOMAS W. KRAUSE, MOLLY R. SILFEN.
                ______________________

     Before MOORE, MAYER, and STOLL, Circuit Judges.
MAYER, Circuit Judge.
    Power Integrations, Inc. (“Power Integrations”) ap-
peals the remand decision of the Patent Trial and Appeal
Board (“board”) rejecting claims 1, 17, 18, and 19 of U.S.
2                            IN RE: POWER INTEGRATIONS, INC.

Patent No. 6,249,876 (“the ’876 patent”) as anticipated.
See In re Power Integrations, Inc., No. 90/008,326, 2016
Pat. App. LEXIS 11870 (P.T.A.B. Oct. 4, 2016) (“Remand
Decision”). Because the board’s anticipation rejections
were based on an unreasonably broad claim construction,
we reverse.
                      I. BACKGROUND
                    A. The ’876 Patent
    The ’876 patent is entitled “Frequency Jittering Con-
trol for Varying the Switching Frequency of a Power
Supply.” It describes a technique for reducing electro-
magnetic interference (“EMI”) noise “by jittering the
switching frequency of a switched mode power supply.”
’876 patent, col.1 ll.66–67. Claim 1, as amended, recites:
    A digital frequency jittering circuit for varying the
    switching frequency of a power supply, compris-
    ing:
         an oscillator for generating a signal having a
    switching frequency, the oscillator having a con-
    trol 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 oscilla-
    tor, the digital to analog converter coupled to the
    counter, the counter causing the digital to analog
    converter to adjust the control input and to vary
    the switching frequency of the power supply.
J.A. 817.
    Claims 17 and 19 relate to a method for varying the
switching frequency using a varying voltage to control the
oscillator. Independent claim 17, as amended, requires
IN RE: POWER INTEGRATIONS, INC.                           3

“cycling a counter” to generate a secondary voltage that
varies over time:
   A method for generating a switching frequency in
   a power conversion system, comprising:
       generating a primary voltage;
       cycling a counter coupled to one or more sec-
   ondary voltage sources to generate a secondary
   voltage which varies over time; and
       combining the secondary voltage with the
   primary voltage to be received at a control input of
   a voltage-controlled oscillator for generating the
   switching frequency of the power conversion sys-
   tem which is varied over time.
J.A. 819–20.
               B. District Court Proceedings
    The ’876 patent is no stranger to litigation. In 2004,
Power Integrations brought suit against Fairchild Semi-
conductor International, Inc. and related parties (collec-
tively “Fairchild”) in the United States District Court for
the District of Delaware. See Power Integrations, Inc. v.
Fairchild Semiconductor Int’l, Inc., 422 F. Supp. 2d 446,
448 (D. Del. 2006) (“Power Integrations I”), aff’d in part,
rev’d in part, vacated in part, 711 F.3d 1348 (Fed. Cir.
2013) (“Power Integrations III”). It alleged that Fairchild
had willfully infringed the ’876 patent, as well as U.S.
Patent Nos. 4,811,075, 6,107,851, and 6,229,366. During
claim construction proceedings, Power Integrations ar-
gued that the term “coupled” in claim 1 of the ’876 patent,
when read in light of the specification and surrounding
claim language, required two circuits to be connected in a
manner “such that voltage, current or control signals pass
from one to another.” Id. at 455–56 (citations and inter-
nal quotation marks omitted). It further contended that
the “recited coupling” between the counter and the digital
4                           IN RE: POWER INTEGRATIONS, INC.

to analog converter must be “present for the purposes of
control.” Id. at 455 (citations and internal quotation
marks omitted). The district court adopted Power Inte-
grations’ proposed claim construction, concluding that it
was “consistent with the claim language and the context
of the specification which describes the purpose for which
various parts of the claimed invention are coupled.” Id. at
456. The court emphasized, moreover, that its construc-
tion of the term “coupled” did not “require a direct connec-
tion or . . . preclude the use of intermediate circuit
elements.” Id.
    In the wake of the trial court’s claim construction,
Fairchild withdrew its anticipation defense, instead
arguing at trial that U.S. Patent No. 4,638,417 (“Martin”)
rendered claim 1 obvious. A jury returned a verdict of
non-obviousness and the district court denied Fairchild’s
motion for judgment as a matter of law. On appeal, this
court affirmed. See Power Integrations III, 711 F.3d at
1366–69. We noted that the “salient difference” between
the ’876 patent and Martin is Martin’s inclusion of an
erasable programmable read-only memory (“EPROM”)
between the counter and the digital to analog converter.
Id. at 1366. We explained that Martin “always includes
an EPROM memory between the counter and digital-to-
analog converter” and “does not teach removing the
EPROM . . . as in the ’876 Patent.” Id. at 1367. We also
noted that “Martin’s sole figure indicates that the
EPROM is just as integral as the circuit’s other compo-
nents,” id., and that “Martin’s EPROM converts ordinary
frequency-jittering, as in the ’876 Patent, to ‘masked’
frequency-jittering,” id. at 1368. We concluded, moreover,
that “substantial evidence of objective considerations of
non-obviousness [supported] the jury’s conclusion that
claim 1 of Power Integrations’ ’876 Patent would not have
been obvious to the ordinarily skilled artisan.” Id. at
1369.
IN RE: POWER INTEGRATIONS, INC.                          5

    In 2016, we affirmed a jury’s determination that claim
1 was not invalid as anticipated by Martin or Andrew C.
Wang & Seth R. Sanders, Programmed Pulsewidth Modu-
lated Waveforms for Electromagnetic Interference Mitiga-
tion in DC–DC Converters, 8 IEEE Transactions on Power
Elecs. 596–605 (1993) (“Wang”). See Power Integrations,
Inc. v. Fairchild Semiconductor Int’l, Inc., 843 F.3d 1315,
1327–29 (Fed. Cir. 2016) (“Power Integrations V”). We
explained that while both Martin and Wang “reduce the
EMI signature associated with a power supply’s oscilla-
tor,” they “accomplish this reduction by varying the
oscillator frequency through the use of a pseudo-random
code stored in read-only memory (ROM).” Id. at 1327.
The “result” of this arrangement is that the frequency
varies according to data stored in the memory. Id. at
1328.
     We further explained that in both Martin and Wang
“[t]he ROM takes the output of the upstream counter as
its input,” and “then outputs a different, stored value to
the digital-to-analog converter.” Id. at 1329. In Martin
and Wang, “[t]he addition of the ROM . . . ensures that no
voltage, current or control signals pass from the counter
to the digital-to-analog converter.” Id. (citations and
internal quotation marks omitted). Because Martin and
Wang “decouple[]” the counter and the digital to analog
converter, we concluded that substantial evidence sup-
ported the determination that these references did not
disclose claim 1’s “coupled” limitation. Id.
              C. Reexamination Proceedings
    In December 2006, while district court proceedings
were pending, the United States Patent and Trademark
Office (“PTO”) granted Fairchild’s request for ex parte
reexamination of claims 1, 17, 18, and 19 of the ’876
patent. The board affirmed the examiner’s rejection of
claim 1 as anticipated by Martin and Wang, as well as by
Thomas G. Habetler & Deepakraj M. Divan, Acoustic
6                           IN RE: POWER INTEGRATIONS, INC.

Noise Reduction in Sinusoidal PWM Drives Using a
Randomly Modulated Carrier, 6 IEEE Transactions on
Power Elecs. 356–63 (1991) (“Habetler”). See In re Power
Integrations, Inc., No. 2010-011021, 2010 Pat. App.
LEXIS 19305, at *7–12 (P.T.A.B. Dec. 22, 2010) (“Power
Integrations II”). The board rejected Power Integrations’
argument that “the respective counters in Martin, Wang
and Habetler are not coupled to the respective digital to
analog converters because [they] disclose a ROM separat-
ing a counter from a digital to analog converter.” Id. at *8
(citations and internal quotation marks omitted). In-
stead, relying on one of a number of definitions of the
term “couple” in a generalist dictionary, the board deter-
mined that the term meant “‘to join (electric circuits or
devices) into a single . . . circuit.’” Id. at *7 (quoting
Webster’s Third Int’l Dictionary of the English Language
Unabr. 521 (Philip B. Gove ed., 1993) (“Webster’s Diction-
ary”)). Applying this construction, the board held that
Martin, Wang, and Habetler each disclosed a counter
“coupled” to a digital to analog converter because the two
components were joined in one circuit. Id. at *9. The
board did not address the district court’s conclusion that
claim 1’s “coupled” limitation requires the counter and the
digital to analog converter to be connected in a manner
“such that voltage, current or control signals pass from
one to another,” Power Integrations I, 422 F. Supp. 2d at
455–56.
    The board also affirmed the examiner’s rejection of
claims 17, 18, and 19 as anticipated by Habetler. In light
of its construction of the term “coupled” in claim 1, the
board rejected Power Integrations’ argument that
Habetler did not anticipate because it includes an
EPROM between the counter and the digital to analog
converter. See Power Integrations II, 2010 Pat. App.
LEXIS 19305, at *12. The board further rejected Power
Integrations’ argument that Habetler failed to disclose
IN RE: POWER INTEGRATIONS, INC.                             7

the claimed primary and secondary voltage sources. See
id. at *13–15.
    After the board denied its petition for rehearing, Pow-
er Integrations appealed to this court. We vacated the
board’s decision, stating that it had “fundamentally
misconstrued Power Integrations’ principal claim con-
struction argument and failed to provide a full and rea-
soned explanation of its decision to reject claim 1 of the
’876 patent as anticipated.” Power Integrations, Inc. v.
Lee, 797 F.3d 1318, 1323–24 (Fed. Cir. 2015) (“Power
Integrations IV”). We explained that the board had “failed
to straightforwardly and thoroughly assess the critical
issue of whether claim 1, when viewed in light of the
specification and the surrounding claim language, re-
quires the counter itself—and not the counter and a
memory functioning together—to drive the digital to
analog converter to adjust the control input and to vary
the switching frequency of the power supply.” Id. at 1325
(footnote omitted).
     We acknowledged that “the board is not generally
bound by a prior judicial construction of a claim term” and
that “in reexamination [the board] applies a different
claim construction standard than that applied by a dis-
trict court.” Id. at 1326. We concluded, however, that
since “Power Integrations’ principal argument to the
board about the proper interpretation of the term ‘cou-
pled’ was expressly tied to the district court’s claim con-
struction, . . . the board had an obligation . . . to evaluate
that construction and to determine whether it was con-
sistent with the broadest reasonable construction of the
term.” Id. at 1327.
     On remand, the board acknowledged that this court
had expressed “concern” that its original decision had
failed to assess whether the district court’s interpretation
of the term “coupled” was consistent with the broadest
reasonable construction of the term. Remand Decision,
8                           IN RE: POWER INTEGRATIONS, INC.

2016 Pat. App. LEXIS 11870, at *9. It concluded, howev-
er, that a comparison of its claim construction with that of
the district court was “unwarranted.” Id. In the board’s
view, a district court’s claim construction is “typically”
narrower than the broadest reasonable construction of a
term. Id. at *16.
    In again affirming the examiner’s rejection of claims
1, 17, 18, and 19 as anticipated, the board continued to
adhere to a generalist dictionary definition of the term
“coupled.” Id. at *8. The board stated that it could
“glean[] no substantial guidance from either the context of
the claim itself or the Specification” regarding the mean-
ing of the term. Id. The board determined, moreover,
that “even if claim 1 requires the counter to drive the
digital to analog converter,” this “does not preclude the
counter and a memory functioning together” to cause the
converter to adjust the control input. Id. at *14.
   Power Integrations then appealed to this court. We
have jurisdiction under 28 U.S.C. § 1295(a)(4)(A) and 35
U.S.C. § 141(b).
                      II. DISCUSSION
                  A. Claim Construction
    “If the intrinsic record fully governs the proper con-
struction of a term, we review the [b]oard’s claim con-
struction de novo.” Wasica Fin. GmbH v. Cont’l Auto.
Sys., Inc., 853 F.3d 1272, 1278 (Fed. Cir. 2017). During
reexamination, “the PTO must give claims their broadest
reasonable construction consistent with the specification.”
In re ICON Health & Fitness, Inc., 496 F.3d 1374, 1379
(Fed. Cir. 2007). Even under the broadest reasonable
construction rubric, however, the board must always
“consider the claims in light of the specification and
teachings in the underlying patent.” In re CSB-Sys. Int’l,
Inc., 832 F.3d 1335, 1341 (Fed. Cir. 2016) (citations and
internal quotation marks omitted). And there is no
IN RE: POWER INTEGRATIONS, INC.                               9

reason why this construction could not coincide with that
of a court in litigation.
                B. The “Coupled” Limitation
    Claim 1 of the ’876 patent recites a “circuit” comprised
of an oscillator, a digital to analog converter, and a coun-
ter. J.A. 817. It further specifies that “the digital to
analog converter [is] coupled to the counter, the counter
causing the digital to analog converter to adjust the
control input and to vary the switching frequency of the
power supply.” J.A. 817. The district court and the board
interpreted this claim language very differently. 1 Relying
exclusively on a definition from Webster’s Dictionary, the
board determined that the “coupled” limitation requires
only that two components be “‘join[ed] . . . into a single . . .
circuit.’” Remand Decision, 2016 Pat. App. LEXIS 11870,
at *8 (quoting Webster’s Dictionary 521). It further
determined that claim 1 does not require the counter
itself to “cause” the digital to analog converter to adjust
the control input and to vary the switching frequency.
Id. at *14. Instead, according to the board, the claim
permits a “counter and a memory functioning together” to
drive the digital to analog converter. Id.
    The district court, by contrast, concluded that “in light
of the claim language and specification,” the “coupled”
limitation requires a specific control relationship between
the counter and the converter. Power Integrations I, 422

    1   We have twice applied the district court’s con-
struction of the “coupled” limitation. See Power Integra-
tions V, 843 F.3d at 1329 (upholding a jury verdict that
claim 1 was not anticipated by Martin or Wang); Power
Integrations III, 711 F.3d at 1366–69 (upholding a jury
verdict that claim 1 was not obvious in view of Martin).
The parties did not challenge the district court’s claim
construction in either of these previous appeals.
10                           IN RE: POWER INTEGRATIONS, INC.

F. Supp. 2d at 455. Thus, the counter must be connected
to the digital to analog converter in a way that allows the
counter to pass “voltage, current or control signals” to it.
Id. at 456. In other words, the counter itself drives the
digital to analog converter. See id. at 455–56.
     “While the broadest reasonable interpretation stand-
ard is broad, it does not give the [b]oard an unfettered
license to interpret the words in a claim without regard
for the full claim language and the written description.”
Trivascular, Inc. v. Samuels, 812 F.3d 1056, 1062 (Fed.
Cir. 2016). The board’s claim construction here was
unreasonably broad and improperly omitted any consid-
eration of the disclosure in the specification. See Novartis
Pharm. Corp. v. Abbott Labs., 375 F.3d 1328, 1334 (Fed.
Cir. 2004) (“Even when guidance is not provided in explic-
it definitional format, the specification may define claim
terms by implication such that the meaning may be found
in or ascertained by a reading of the patent documents.”
(citations and internal quotation marks omitted)); Slim-
fold Mfg. Co. v. Kinkead Indus., Inc., 810 F.2d 1113, 1116
(Fed. Cir. 1987) (“Claims are not interpreted in a vacuum,
but are part of and are read in light of the specification.”).
    Under the board’s overly expansive view of the term
“coupled,” every element anywhere in the same circuit is
potentially “coupled” to every other element in that cir-
cuit, no matter how far apart they are, how many inter-
vening components are between them, or whether they
are connected in series or in parallel. See In re Suitco
Surface, Inc., 603 F.3d 1255, 1260 (Fed. Cir. 2010) (“The
broadest-construction rubric coupled with the term ‘com-
prising’ does not give the PTO an unfettered license to
interpret claims to embrace anything remotely related to
the claimed invention.”).      On appeal, the Director
acknowledges that claim 1 requires some type of “func-
tional relationship between the counter and the digital-to-
analog converter.” The problem is that the board’s claim
construction does not define what type of functional
IN RE: POWER INTEGRATIONS, INC.
                                                        11

relationship is required. The board suggests that the
counter will “cause” the digital to analog converter to
adjust the control input and to vary the switching fre-
quency regardless of how insignificantly or indirectly the
counter’s output affects the converter’s behavior. See
Remand Decision, 2016 Pat. App. LEXIS 11870, at *14
(concluding that the counter “causes” the digital to analog
converter to adjust the control input and to vary the
switching frequency even if the switching frequency
varies according to data contained in a memory).
    “[C]laim construction must begin with the words of
the claims themselves.” Amgen Inc. v. Hoechst Marion
Roussel, Inc., 457 F.3d 1293, 1301 (Fed. Cir. 2006). By its
plain terms, claim 1 requires the counter to “caus[e]” the
converter to adjust the control input and to vary the
switching frequency. J.A. 817. Nothing in the claim
language suggests that this requirement will be met if, as
in the prior art, the digital to analog converter’s output
varies based on data stored in a memory rather than
according to signals relayed from the counter itself. See
Power Integrations V, 843 F.3d at 1329 (explaining that in
Martin and Wang the frequency of the oscillator is varied
“through the use of a pseudo-random code stored in read-
only memory (ROM)”).
    Another problem with the board’s claim construction
is that it renders claim language meaningless. As dis-
cussed above, claim 1 begins by reciting a “circuit” that
includes both a counter and a digital to analog converter.
J.A. 817. The phrase “the digital to analog converter [is]
coupled to the counter,” J.A. 817, would be superfluous if,
as the board said, it means only that the two components
are in the same circuit. See, e.g., Bicon, Inc. v. Strau-
mann Co., 441 F.3d 945, 950–51 (Fed. Cir. 2006) (refusing
to construe claim terms in a way that made other claim
limitations meaningless); Merck & Co. v. Teva Pharm.
USA, Inc., 395 F.3d 1364, 1372 (Fed. Cir. 2005) (“A claim
12                           IN RE: POWER INTEGRATIONS, INC.

construction that gives meaning to all the terms of the
claim is preferred over one that does not do so.”).
     Even more fundamentally, the board’s unduly broad
reading of the language of claim 1 is unsupported by the
specification. See PPC Broadband, Inc. v. Corning Opti-
cal Commc’ns RF, LLC, 815 F.3d 747, 752 (Fed. Cir. 2016)
(“The fact that [a claim term] has multiple dictionary
meanings does not mean that all of these meanings are
reasonable interpretations in light of [the] specification.”).
The ’876 patent strives to eliminate unnecessary compo-
nents and create a more compact circuit. See, e.g., ’876
patent, col.1 ll.50–62 (explaining that “EMI may be re-
duced in a power supply by adding snubbers and input
filters,” but that “extra components can undesirably
increase the size and weight of the power supply and thus
the resulting product”); id. col.4 ll.9–10 (emphasizing that
an advantage of the claimed invention is that it can create
“a compact and inexpensive power supply system . . . with
minimal EMI emissions”). The inclusion of a bulky pre-
programmed memory between the counter and the digital
to analog converter is inconsistent with the ’876 patent’s
focus on minimizing circuit size. See Power Integrations
III, 711 F.3d at 1368 (relying on testimony explaining
that including a memory between the counter and the
converter “adds expense and imposes design constraints”
and that “because of its components, Martin’s circuit
cannot be integrated on a single chip”).
     Notably, moreover, every embodiment disclosed in the
’876 patent shows a counter that passes voltage, current,
or control signals to the digital to analog converter. See
Astrazeneca AB, Aktiebolaget Hassle, KBI-E, Inc. v. Mut.
Pharm. Co., 384 F.3d 1333, 1340 (Fed. Cir. 2004) (“[W]hile
it is of course improper to limit the claims to the particu-
lar preferred embodiments described in the specification,
the patentee’s choice of preferred embodiments can shed
light on the intended scope of the claims.”). Figure 1
depicts a counter directly connected to the digital to
IN RE: POWER INTEGRATIONS, INC.
                                                          13

analog converter, J.A. 15, and the accompanying descrip-
tion emphasizes that it is the “outputs” of the counter that
drive the digital to analog converter. ’876 patent, col.4
l.63; see also id. col.5 ll.52–55 (explaining that the “coun-
ter drives a plurality of current sources . . . such that the
frequency of the primary oscillator is varied” (diagram
numbers omitted)). Figure 2 shows that the step-wise
increases in switching frequency are based on the outputs
of the counter. J.A. 16; see also ’876 patent, col.5 l.57–
col.6 l.5. By contrast, nothing in the specification sug-
gests that the claims can be stretched to cover a system in
which a memory separates the counter and the digital to
analog converter and severs the requisite control relation-
ship between them.
    In the board’s view, claim 1 can be expanded to en-
compass a circuit in which the switching frequency varies
based on data from a memory because neither the claim
language nor the specification “requir[es] the lack of a
memory.” Remand Decision, 2016 Pat. App. LEXIS
11870, at *13. This reasoning is unpersuasive. “The
correct inquiry in giving a claim term its broadest reason-
able interpretation in light of the specification is not
whether the specification proscribes or precludes some
broad reading of the claim term adopted by the examin-
er.” In re Smith Int’l, Inc., 871 F.3d 1375, 1382–83 (Fed.
Cir. 2017). Instead, a proper claim construction analysis
endeavors to assign a meaning to a disputed claim term
“that corresponds with . . . how the inventor describes his
invention in the specification.” Id. at 1383. Although the
’876 patent does not expressly exclude a circuit in which a
pre-programmed memory is placed between the counter
and the digital to analog converter and dictates the con-
verter’s behavior, such an arrangement is inconsistent
with both the specification which, as discussed above,
emphasizes the need to minimize circuit size and the
plain claim language which specifically requires the
14                          IN RE: POWER INTEGRATIONS, INC.

counter—not some other circuit element—to “caus[e]” the
converter to adjust the control input, J.A. 817.
              C. The Anticipation Rejections
    Because the board’s decision affirming the examiner’s
rejection of claim 1 was based on an erroneous claim
construction and the rejection is not supported under the
proper construction, we reverse the rejection of claim 1.
See, e.g., Smith, 871 F.3d at 1382–84 (reversing an antici-
pation rejection because it was predicated on an unrea-
sonably broad claim construction); Smith & Nephew, Inc.
v. Rea, 721 F.3d 1371, 1380 (Fed. Cir. 2013) (reversing the
board’s non-obviousness determination because it “was
mainly the result of . . . analytical errors” and “the facts
[were] largely undisputed”); In re Skvorecz, 580 F.3d
1262, 1268 (Fed. Cir. 2009) (reversing the board’s decision
to reject reissue claims as anticipated because it was
based on an unreasonably broad claim construction and
explaining that “[a]nticipation cannot be found, as a
matter of law, if any claimed element or limitation is not
present in the reference”).       In Martin, Wang, and
Habetler, the prior art relied upon by the board, no volt-
age, current, or control signals pass from the counter to
the digital to analog converter. 2 See Power Integrations

     2   Martin relies on an EPROM to vary the frequency
in a “pseudo-random” manner. J.A. 1443. An oscillator
generates the switching frequency, and then part of the
oscillator’s output is “fed back to [the] counter,” which
sends a signal to the memory that “selectively steps” the
memory “through its addressing routine” for varying the
switching frequency. J.A. 1443. The memory relays its
instructions to the digital to analog converter, which
transforms those digital instructions to an analog signal
that is supplied to the oscillator. J.A. 1443.
    Wang describes a method of programming a memory
to vary the switching frequency of a circuit used with a
IN RE: POWER INTEGRATIONS, INC.
                                                         15

V, 843 F.3d at 1329 (explaining that “[t]he addition of [a
memory] . . . ensures that no voltage, current or control
signals pass from the counter to the digital-to-analog
converter” (citations and internal quotation marks omit-
ted)); see also J.A. 760–62. In each of these references,
the counter is separated from the digital to analog con-
verter by a pre-programmed memory. J.A. 1441–44, 1448,
1453–61. This pre-programmed memory contains data
specifying how to vary the switching frequency, see, e.g.,
J.A. 1442–43, 1448, 1454–60, and the switching frequency
thus changes based on data from the memory, rather than
the output of the counter, as claim 1 requires. See Power
Integrations V, 843 F.3d at 1329 (explaining that in
Martin and Wang the memory “takes the output of the
upstream counter as its input,” and “then outputs a
different, stored value to the digital-to-analog converter”
(emphasis added)). In short, because the prior art relies
on an intervening memory to adjust the control input, it
does not disclose a counter which is “coupled” to a digital

DC-to-DC converter. J.A. 1453–62. In the Wang system,
an oscillator generates a signal having a switching fre-
quency and part of that signal is sent to the counter. J.A.
1461. The counter then sends signals to a memory. J.A.
1461. Next, the memory sends its programmed instruc-
tions to a pair of digital to analog converters, which relay
the memory’s instructions on how to vary the switching
frequency to the oscillator. J.A. 1461.
    Habetler is directed to reducing acoustic noise in an
inverter-driven electric machine. J.A. 1445–52. In the
Habetler system, a triangle generator generates a switch-
ing frequency which is relayed, in part, to a counter. J.A.
1448. The counter sends signals to the memory, which
contains “a large quantity of periodic random numbers”
that are used to vary the switching frequency. J.A. 1448.
The memory then sends instructions to the digital to
analog converter. J.A. 1448.
16                          IN RE: POWER INTEGRATIONS, INC.

to analog converter and “caus[es]” it “to adjust the control
input and to vary the switching frequency of the power
supply,” J.A. 817.
     The board’s unreasonably broad claim construction
also mandates reversal of its anticipation rejections of
claims 17, 18, and 19. Independent claim 17 contains a
“coupled” limitation similar to that in claim 1, reciting “a
counter coupled to one or more secondary voltage sources
to generate a secondary voltage which varies over time,”
J.A. 820. The Director does not dispute that a reversal of
the board’s rejection of claim 1 also mandates reversal of
its rejections of claims 17, 18, and 19. 3
    The board has had two opportunities to come up with
a sustainable interpretation that differs from the one that
survived litigation and has failed. We conclude there is
not one. The district court’s construction of “coupled,” an
interpretation firmly rooted in the plain claim language
and the specification, comports with the broadest reason-
able construction of the term.
                     III. CONCLUSION
    Accordingly, the decision of the Patent Trial and Ap-
peal Board affirming the examiner’s rejections of claims 1,
17, 18, and 19 is reversed.
                       REVERSED

     3  Because we conclude that Habetler does not dis-
close the “coupled” limitation of claims 17, 18, and 19, we
need not reach Power Integrations’ alternative argument
that Habetler does not disclose “generating a primary
voltage,” a “voltage-controlled oscillator,” or “one or more
secondary voltage sources to generate a secondary volt-
age.” J.A. 819–20.