NOTE: This disposition is nonprecedential.

 

United States Court of Appeals 

for the Federal Circuit ______________________ 

SYNQOR, INC.,

Appellant

v.

VICOR CORPORATION,

Appellee

______________________ 

2021-2211

______________________ 

Appeal from the United States Patent and Trademark 

Office, Patent Trial and Appeal Board in No. 95/001,861. 

______________________ 

Decided: January 18, 2023

______________________ 

STEVEN J. HOROWITZ, Sidley Austin LLP, Chicago, IL, 

argued for appellant. Also represented by THOMAS D. REIN,

PAUL J. ROGERSON; MICHAEL D. HATCHER, Dallas, TX. 

 MATTHEW A. SMITH, Smith Baluch LLP, Washington, 

DC, argued for appellee. Also represented by ELIZABETH A.

LAUGHTON. 

 ______________________ 

Before MOORE, Chief Judge, TARANTO and CHEN, Circuit 

Judges.

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2 SYNQOR, INC. v. VICOR CORPORATION

CHEN, Circuit Judge. 

In 2017, we affirmed-in-part, vacated-in-part, and remanded the Patent Trial and Appeal Board’s (Board) decision in an inter partes reexamination of U.S. Patent No. 

8,023,290 (’290 patent). Vicor Corp. v. SynQor, Inc., 869 

F.3d 1309, 1312 (Fed. Cir. 2017) (SynQor III). On remand, 

the Board held all of the ’290 patent’s claims unpatentable 

under 35 U.S.C § 103 over two different combinations of 

references. Because the Board’s fact findings are supported by substantial evidence and its unpatentability determination is correct as to the second combination of 

references, we affirm. 

BACKGROUND

The ’290 patent is entitled “High Efficiency Power Converter” and claims a system for DC-DC power conversion—

i.e., converting a direct current (DC) source from one voltage level to another. ’290 patent col. 17 l. 9 – col. 18 l. 35. 

The ’290 patent is part of a patent family owned by SynQor, 

Inc. (SynQor) involving DC-DC conversion, and we have 

previously discussed that technology in SynQor III. See

869 F.3d at 1312–15. The ’290 patent family describes a 

“two-stage architecture” for DC-DC converters, which 

SynQor refers to as “Intermediate Bus Architecture” (IBA). 

Id. at 1314. The ’290 patent claims a particular type of IBA 

converter implemented using switching regulators. Id.; 

’290 patent col. 17 ll. 26–30.

In SynQor III, we reviewed the Board’s decision affirming an examiner’s reexamination decision withdrawing six 

proposed rejections of the ’290 patent and vacated and remanded with respect to four proposed rejections: (i) two 

rejections based on a combination of JP ’4461 and Steigerwald ’5392 (Rejections III and IV), and (ii) two rejections 

1 Japanese Patent App. Pub. No. H05-64446. 2 U.S. Patent No. 5,274,539.

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based on a combination of Steigerwald ’0903 and Pressman4 (Rejections V and VI). 869 F.3d at 1320–24. We instructed the Board to consider SynQor’s secondary 

considerations evidence for nonobviousness in light of a 

previous SynQor decision by our court that held that claims 

of a SynQor patent related to the ’290 patent and directed 

to “IBA’s basic arrangement” were anticipated. Id. at 1322

(citing Vicor Corp. v. SynQor, Inc., 603 F. App’x 969, 975 

(Fed. Cir. 2015) (SynQor II)). More specifically, we instructed the Board to consider whether SynQor’s secondary 

considerations evidence “is attributable to IBA—as anticipated in SynQor II—or to other features in the SynQor Patents’ claims.” Id. We observed that SynQor II might be 

“particularly relevant for the proposed rejections . . . given 

SynQor’s almost singular focus on IBA as a general concept 

in its prior arguments before the Board on the [secondary 

considerations] evidence.” Id.

On remand, the Board reversed the examiner’s withdrawal decision, found no nexus between SynQor’s secondary considerations evidence and the claims of the ’290 

patent, and entered new grounds of rejection for claims 1–

15 based on proposed Rejections III–VI. J.A. 17246–48, 

J.A. 17253–56. In view of the new rejections, SynQor requested that the examiner reopen prosecution. J.A. 17357–

419. After considering SynQor and Vicor Corp.’s (Vicor) remarks regarding inter alia obviousness, the examiner 

maintained the Board’s obviousness rejections of claims 1–

15 based on Rejections III–VI. J.A. 17954. 

The Board subsequently affirmed the examiner’s determination as to claims 1–15, finding that the prior art references set forth in Rejections III–VI taught all the 

limitations of the claims and that a skilled artisan would 

3 U.S. Patent No. 5,377,090. 4 Abraham I. Pressman, Switching and Linear 

Power Supply, Power Converter Design (1977).

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have been motivated to combine the references. J.A. 52–

67, 71–87, 91–96. After reconsidering the secondary considerations evidence in view of SynQor’s additional remarks, the Board nonetheless found no nexus between 

such evidence and the claimed invention. J.A. 67–71, 87–

90. Accordingly, the Board found that Vicor’s evidence of 

obviousness outweighed SynQor’s evidence of nonobviousness. J.A. 71, 90. 

SynQor timely appealed the Board’s decision. We have 

jurisdiction under 28 U.S.C. § 1295(a)(4)(A).

DISCUSSION

We review the Board’s ultimate obviousness determination de novo and its underlying factual findings for substantial evidence. PersonalWeb Techs., LLC v. Apple, Inc., 

917 F.3d 1376, 1381 (Fed. Cir. 2019) (citation omitted). 

Relevant here, factual findings underlying an obviousness determination include: (1) whether a skilled artisan 

would have been motivated to modify the teachings of a reference, and (2) whether there is a nexus between secondary 

considerations of nonobviousness and the claimed invention. WBIP, LLC v. Kohler Co., 829 F.3d 1317, 1327, 1331–

32 (Fed. Cir. 2016). A patentee may establish nexus by 

showing that the secondary considerations evidence is a 

“direct result of the unique characteristics of the claimed 

invention.” Fox Factory, Inc. v. SRAM, LLC, 944 F.3d 

1366, 1373–74 (Fed. Cir. 2019) (quoting In re Huang, 100 

F.3d 135, 140 (Fed. Cir. 1996)). For patents claiming combinations of prior art features, a patentee must show that 

the secondary considerations evidence is “attributable to 

the claimed combination of [prior art features], as opposed 

to, for example, prior art features in isolation or unclaimed 

features.” Id. at 1378 (citing Ethicon Endo-Surgery, Inc. v. 

Covidien LP, 812 F.3d 1023, 1034 (Fed. Cir. 2016)).

SynQor argues the Board: (1) erred in declining to apply issue preclusion to Rejections III and IV, Appellant’s 

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Br. 29–40; (2) improperly relied on conclusory assertions 

regarding the knowledge of a skilled artisan as to Rejections III and IV, id. 41–54; (3) failed to articulate a motivation to combine for Rejections V and VI, id. 54–66; and (4) 

erred in evaluating the secondary considerations evidence, 

id. 66–74. We disagree with SynQor as to its third and 

fourth arguments regarding Rejections V and VI and secondary considerations. Because our decision on these arguments resolves the parties’ dispute as to claims 1–15, we 

do not address SynQor’s remaining arguments.

I. Rejections V and VI: Obviousness over 

Steigerwald ’090 and Pressman

The Board found, and SynQor does not challenge, that: 

(1) Steigerwald ’090 discloses each limitation of claim 1, except that it discloses “series regulators” instead of the 

claimed “switching regulators,” and (2) Pressman discloses 

the missing “switching regulators.” J.A. 76, 79. The Board 

determined that a skilled artisan would have been motivated to modify Steigerwald ’090’s circuit using Pressman’s 

switching regulators for certain circuit outputs—the nonpulsed bias voltage outputs “used for control and receive 

functions.” J.A. 79–80, 87; see also id. 79–86. The Board 

reasoned that using switching regulators for the nonpulsed bias voltage outputs would “improve efficiency as 

taught by Pressman” “relative to linear [i.e., series5] 

5 The Board’s opinion uses the terms “linear regulators” and “series regulators” interchangeably. Compare

J.A. 64 (referring to Steigerwald ’090’s regulators 50, 51, 

60, and 61 as “linear regulators”), with J.A. 76, 79 (referring to Steigerwald ’090’s regulators 50, 51, 60, and 61 as 

“series regulators”). To the extent the Board’s opinion refers to linear regulators, we understand it to refer to Steigerwald ’090’s series regulators.

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6 SYNQOR, INC. v. VICOR CORPORATION

regulators when used in Steigerwald ’090’s configuration.” 

J.A. 79–81, 86. Substantial evidence supports this finding. 

Specifically, the Board’s finding is supported by Pressman itself and by the testimony of Dr. Vinciarelli, Vicor’s 

expert. Pressman discloses a circuit that uses a “switching 

postregulator.” Pressman at 82–83, Fig. 3–4B. Pressman 

teaches that this circuit can “generate a multiplicity of different output voltages at high efficiency” due to “the use of 

switching postregulators” and that this efficiency could not 

be achieved with “series-pass postregulators.” Pressman 

at 83 (emphasis added). Dr. Vinciarelli, in turn, explains 

that Pressman’s series-pass regulators are “equivalent to” 

Steigerwald ’090’s series regulators. J.A. 17753–54 ¶ 8. 

Thus, Pressman provides an express motivation to combine 

the two references by teaching that its switching regulators, which can be used in place of Steigerwald’s ’090 series 

regulators, improve efficiency. 

SynQor makes four arguments on appeal, but two are 

unpersuasive and two are forfeited. First, SynQor argues 

that the Board’s analysis failed to explain why a skilled artisan would have been motivated to select Steigerwald ’090

and Pressman for combination. Appellant’s Br. 55–56, 

58–61, 64–66 (citing WBIP, 829 F.3d at 1337). But it is 

undisputed that (1) the claims and Steigerwald ’090 are 

analogous art, both directed to two-stage DC-DC converters, and (2) Pressman discloses a benefit to using switching 

regulators in a two-stage DC-DC converter circuit—such as 

those disclosed in Steigerwald ’090—to improve efficiency. 

As such, the Board articulated a valid motivation to combine, and no further explanation is required. See Polaris 

Indus., Inc. v. Arctic Cat, Inc., 882 F.3d 1056, 1070–71 

(Fed. Cir. 2018) (citing WBIP, 829 F.3d at 1337). 

Second, SynQor argues that adding switching regulators to the non-pulsed bias voltage outputs would not improve the efficiency of Steigerwald ’090’s circuit because 

bias voltages draw almost no power. Appellant’s Br. 63–64

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(citing J.A. 17489–90 ¶¶ 31–32). We have reviewed 

SynQor’s cited expert testimony, but find little support for 

SynQor’s attorney argument. See J.A. 17489–90 ¶¶ 31–32. 

SynQor’s remaining two arguments were not presented 

to the Board: (1) skilled artisans would not have been motivated to select Steigerwald ’090’s circuit for modification

because two-stage architectures had been discredited, Appellant’s Br. 57–58; and (2) Pressman teaches away from 

using a two-stage architecture, id. 61–62, 65. SynQor forfeited these arguments by not first raising them to the 

Board, and we decline to address these fact-bound contentions in the first instance. See In re Google Tech. Holdings 

LLC, 980 F.3d 858, 863 (Fed. Cir. 2020) (explaining that an 

argument not presented to the tribunal under review is forfeited absent exceptional circumstances). 

Accordingly, substantial evidence supports the Board’s 

finding that a skilled artisan would have been motivated to 

combine Steigerwald ’090 and Pressman.

II. Secondary Considerations

We agree with the Board that SynQor’s secondary considerations evidence is not tied to the claimed combination 

of features in the ’290 patent—i.e., an IBA converter using

switching regulators. Instead that evidence is associated 

with IBA without any requirement for switching regulators.6 The Board relied on SynQor’s expert, Dr. Schlecht, 

6 The record shows that SynQor’s understanding of 

“IBA” does not require using switching regulators, given 

that it refers to “IBA” to describe its patent claims across 

multiple patents collectively, including claims that do not 

recite switching regulators. See, e.g., J.A. 1199–1200, 

1212, 1242 (discussing secondary considerations evidence 

related to the ’290 patent and U.S. Patent Nos. 7,072,190

and 7,272,021), 18052 (“[A]ll the ’290 Patent claims require 

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who testified that certain indicia of secondary considerations—e.g., commercial success, skepticism, widespread 

adoption, and industry praise—were due to aspects of IBA 

unrelated to switching regulators. See Declaration of Martin F. Schlecht, Sc.D., filed May 2, 2012 in Reexamination 

Control No. 95/001,861, ¶¶ 59, 61, 63, 109, 112, 114; J.A. 

88 (citing J.A. 17246–47). We agree with the Board’s assessment that Dr. Schlecht’s testimony only ties the secondary considerations evidence to IBA converters without 

any discussion as to the significance of switching regulators, and thus there is no nexus. 

SynQor’s arguments fail because it has not shown that 

its relied-on success, skepticism, adoption, or praise, etc., 

were a “direct result of the unique characteristics of the 

claimed invention”—in this case, were “attributable to the 

claimed combination of [prior art features], as opposed to, 

for example, prior art features in isolation or unclaimed 

features.” Fox Factory, 944 F.3d at 1373–74, 1378 (citation 

omitted). We do not discern any showing by SynQor on appeal before this court or in the Board proceeding that there 

was a nexus between its secondary considerations evidence 

and the claimed combination of features in the ’290 patent—i.e., an IBA converter using switching regulators. 

See Appellant’s Br. 68–74; J.A. 17416–19, 18050–53.7 The 

the regulation stages to be switching regulators whereas 

the anticipated ’190 Patent claims and ’021 Patent claims 

are more broadly worded to allow all types of non-isolating 

regulation stages.”). 

7 Before the Board, SynQor argued that it was entitled to a presumption of nexus, but it does not argue this 

now on appeal. J.A. 17417–18, 18052–53. Relatedly, 

SynQor argues for the first time in its reply brief that its 

secondary considerations evidence was “reasonably commensurate” with the claims of the ’290 patent. Appellant’s 

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only evidence before the Board was that the secondary considerations evidence was tied to aspects of IBA unrelated 

to switching regulators. 

CONCLUSION

We have considered SynQor’s remaining arguments 

and find them unpersuasive. For the foregoing reasons, 

substantial evidence supports the Board’s fact findings 

that a skilled artisan would have been motivated to combine Steigerwald ’090 and Pressman and SynQor’s secondary considerations evidence lacks an adequate nexus with

the ’290 patent claims. We therefore affirm the Board’s decision. 

AFFIRMED

Reply Br. 31. SynQor did not make either of these arguments in its opening brief, and thus these arguments are 

waived. See SmithKline Beecham Corp. v. Apotex Corp., 

439 F.3d 1312, 1319 (Fed. Cir. 2006) (“[A]rguments not 

raised in the opening brief are waived.”). 

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