       NOTE: This disposition is nonprecedential.


  United States Court of Appeals
      for the Federal Circuit
                ______________________

              VICOR CORPORATION,
                    Appellant

                           v.

                   SYNQOR, INC.,
                       Appellee
                ______________________

                      2016-2282
                ______________________

    Appeal from the United States Patent and Trademark
Office, Patent Trial and Appeal Board in No. 95/001,853.
                  ______________________

               Decided: August 30, 2017
                ______________________

    MATTHEW A. SMITH, Smith Baluch LLP, Washington,
DC, argued for appellant. Also represented by ANDREW T.
D’AMICO, JR., Vicor Corporation, Andover, MA; LAWRENCE
K. KOLODNEY, Fish & Richardson, PC, Boston, MA.

   THOMAS D. REIN, Sidley Austin LLP, Chicago, IL, ar-
gued for appellee. Also represented by CONSTANTINE L.
TRELA, JR., BRYAN C. MULDER.
                ______________________

    Before LOURIE, TARANTO, and CHEN, Circuit Judges.
2                                VICOR CORP.   v. SYNQOR, INC.



CHEN, Circuit Judge.
    Vicor Corporation (Vicor) appeals from a decision of
the Patent Trial and Appeal Board (Board) reversing
certain examiner rejections in an inter partes reexamina-
tion of U.S. Patent No. 7,564,702 (the ’702 patent), owned
by SynQor Inc. (SynQor). The Board held that the chal-
lenged claims of the ’702 patent were patentable as non-
obvious over Vicor’s proposed prior art combinations.
Because the Board’s factual findings are supported by
substantial evidence and the Board’s conclusions of non-
obviousness are not erroneous, we affirm.
                       BACKGROUND
     The ’702 patent covers direct current-to-direct current
(DC-DC) power conversion technology. See ’702 patent
col. 1 ll. 22–25. In particular, the ’702 patent claims
systems and methods for converting a DC voltage to one
or more lower DC voltages by using a non-regulating
isolation stage and subsequently regulating the lower
voltages using non-isolating switching regulators. See,
e.g., id. col. 17 ll. 2–39. Claim 1 is representative and
recites the following:
        A DC-DC power converter system providing
    plural regulated DC outputs, each having a regu-
    lated voltage, comprising:
       (a) a DC input providing an input voltage
       that varies over a range that is more than
       plus or minus a few percent;
       (b) a non-regulating isolating step-
       down converter through which power
       from the DC input flows first before flow-
       ing through any regulation stage, the non-
       regulating isolating step-down converter
       providing a non-regulated, isolated DC
       output having a non-regulated voltage and
       comprising:
VICOR CORP.   v. SYNQOR, INC.                          3



              (i) at least one transformer that is
              not driven into saturation, the at
              least one transformer having plu-
              ral windings including at least one
              primary winding and at least one
              secondary winding;
              (ii) plural power MOSFET switch-
              es in circuit with the at least one
              primary winding, the plural power
              MOSFET switches causing power
              to flow into the at least one prima-
              ry winding;
              (iii) control circuitry coupled to the
              plural MOSFET switches, the con-
              trol circuitry determining when
              the power MOSFET switches are
              turned on and off in a switching
              cycle at a switching frequency; and
              (iv) plural controlled rectifiers
              in circuit with the at least one sec-
              ondary winding, each having a
              parallel uncontrolled rectifier,
              each controlled rectifier being
              turned on for an on-state time and
              off for an off-state time in syn-
              chronization with a voltage wave-
              form of the at least one primary
              winding to provide the non-
              regulated, isolated DC output, the
              voltage waveform of the at least
              one primary winding having a
              fixed duty cycle and transition
              times which are short relative to
              the on-state and the off-state
              times of the controlled rectifiers;
              and
4                                 VICOR CORP.   v. SYNQOR, INC.



        (c)    plural    non-isolating    down-
        converter switching regulators, each re-
        ceiving power from the non-regulated, iso-
        lated DC output and each providing one of
        the regulated DC outputs having a regu-
        lated voltage.
Id. (emphases added). All of the claims of the ’702 patent
at issue in this appeal require the three limitations shown
in emphasis in claim 1 above, namely: (1) a non-
regulating isolation component, (2) controlled rectifiers
(included as part of the non-regulating isolation compo-
nent), and (3) plural non-isolating switching regulators.
    Vicor requested inter partes reexamination of the ’702
patent on December 14, 2011. J.A. 98–133. The U.S.
Patent and Trademark Office granted the request on
January 19, 2012. J.A. 135–52. The proposed rejections
at issue in this appeal principally relied on three prior art
references: Cobos, 1 Pressman, 2 and Kassakian. 3 Two
combinations of these references are pertinent to this
appeal. The first is Cobos in view of Pressman, which was
used to challenge claims 1, 2, 26–29, 53–55, 67–76, 78, 81,
82, 85, 86, and 89 (Cobos-Pressman). J.A. 142 (rejections
I–III). 4 The second is Pressman in view of Kassakian,


    1   J.A. Cobos & J. Uceda, Low Output Voltage
DC/DC Conversion, IEEE 20th Int’l Conf. on Indus.
Elecs., Control and Instrumentation, at 1676–81 (Sep-
tember 5–9, 1994).
    2   Abraham I. Pressman, Switching and Linear
Power Supply, Power Converter Design (1977).
    3   John G. Kassakian & Martin F. Schlecht, High-
Frequency High-Density Converters for Distributed
Power Supply Systems, 76 Proc. IEEE 362 (Apr. 1988).
    4   The Cobos-Pressman rejections also referenced
Milan M. Jovanovic et al., Distributed Power Systems—
Benefits and Challenges, 77 Int’l J. Electronics 601 (1994)
VICOR CORP.   v. SYNQOR, INC.                            5



which was used to challenge claims 1–3, 12–20, 23, 26,
28–30, 39–43, 44–47, 50, 53, 55, 56, 64, 67, 69, 70–76, 78,
80–82, 84–86, 88, and 89 (Pressman-Kassakian). J.A. 143
(rejections VII and VIII). The examiner adopted both sets
of rejections.
    The Cobos-Pressman rejections relied on Cobos to
supply the non-regulating isolation component required
by the claims. See J.A. 147 (examiner incorporating by
reference Vicor’s proposed rejections (J.A. 114–21)). In
response to the rejections, SynQor argued that Cobos did
not disclose an unregulated isolation component because
the relevant component from Cobos utilized a pulse-width
modulated (PWM) topology which incorporated “feedback
control circuitry” to regulate output voltage. J.A. 197.
Although this feedback control circuitry is not explicitly
shown in Cobos, SynQor presented testimony by SynQor’s
CEO and the sole inventor of the ’702 patent—Dr. Martin
Schlecht—that “such a design would have been inherent
in the PWM architecture.” J.A. 198. SynQor also averred
that the output voltage of Cobos’s alleged non-regulated
isolating component—3.3 volts—was evidence of regula-



(Jovanovic), as evidence of motivation to combine Cobos
and Pressman. The Jovanovic reference is not relevant to
the disposition of this appeal, because Cobos—the sole
reference relied on for disclosure of a non-regulated
isolation component—does not disclose an unregulated
isolation component, as discussed below. At oral argu-
ment, Vicor argued that Jovanovic could serve as an
independent basis for altering Cobos to be non-regulating,
even if Cobos were found to be regulating on its face. Oral
Argument at 6:01–6:34, available at http://oralarguments.
cafc.uscourts.gov/default.aspx?fl=2016-2282.mp3.       This
argument was never raised before the Board and was
therefore waived. See In re Baxter Int’l, Inc., 678 F.3d
1357, 1362 (Fed. Cir. 2012).
6                                VICOR CORP.   v. SYNQOR, INC.



tion, because such a specific voltage level, intended for
powering logic boards, would need to be “tightly regulated
and not vary more than plus or minus a few percent.”
J.A. 197. The Board agreed with SynQor’s positions and
reversed the examiner’s rejections. J.A. 26–27.
     The Pressman-Kassakian rejections relied on Press-
man for both the non-regulating isolation component and
the plural non-isolating switching regulators but proposed
replacing Pressman’s diode rectifiers with controlled
rectifiers as taught by Kassakian. See J.A. 44–46. Specif-
ically, the rejections proposed combining a non-regulated
DC power source from Pressman Figure 3-3 with switch-
ing regulators and other components from Pressman
Figure 3-4(B) and, in the process, removing a pre-
regulator from Figure 3-4(B) to remove regulation from
the isolation stage. Id. For the “controlled rectifiers”
limitation of the claims, the rejections proposed incorpo-
rating Kassakian’s synchronous rectifiers in place of diode
rectifiers in the Pressman combination. J.A. 46. SynQor
argued to the Board that (1) there was no suggestion in
Pressman to make the Pressman combination’s isolation
stage non-regulating by removing Figure 3-4(B)’s pre-
regulator and (2) incorporating Kassakian’s synchronous
rectifiers into Pressman would be “beyond the ordinary
skill in the art.” J.A. 554–55. The Board again agreed
with SynQor and reversed the examiner’s rejections. J.A.
47.
    Vicor timely appealed to this court. We have jurisdic-
tion under 28 U.S.C. § 1295(a)(4)(A).
                       DISCUSSION
    We review the Board’s legal determinations de novo
and its factual findings underpinning those determina-
tions for substantial evidence. ACCO Brands Corp. v.
Fellowes, Inc., 813 F.3d 1361, 1365 (Fed. Cir. 2016). “A
finding is supported by substantial evidence if a reasona-
ble mind might accept the evidence to support the find-
VICOR CORP.   v. SYNQOR, INC.                              7



ing.” K/S Himpp v. Hear–Wear Techs., LLC, 751 F.3d
1362, 1364 (Fed. Cir. 2014) (citation omitted). Obvious-
ness “is a question of law based on underlying findings of
fact.” In re Gartside, 203 F.3d 1305, 1316 (Fed. Cir. 2000)
(citation omitted). The factual analysis is framed by the
factors set out in Graham v. John Deere Co. of Kansas
City: (1) “the scope and content of the prior art,” (2) “dif-
ferences between the prior art and the claims at issue,” (3)
“the level of ordinary skill in the pertinent art,” and (4)
“secondary considerations” such as “commercial success,
long felt but unsolved needs,” and “failure of others.” 383
U.S. 1, 3 (1966).
                      I. Cobos-Pressman
     Vicor contends that the Board erred in reversing the
examiner’s rejections based on the Cobos-Pressman
combination, arguing that no substantial evidence sup-
ports the Board’s finding that Cobos fails to teach a non-
regulated isolation component. In particular, Vicor ar-
gues that Dr. Schlecht’s testimony regarding PWM con-
trol circuitry “could not have been credited by a
reasonable factfinder, because Dr. Schlecht has an inter-
est in the outcome.” Open. Br. 47. SynQor counters that
the Board was aware of Dr. Schlecht’s interest in the
litigation and that the Board was entitled to weigh his
credibility and rely on his testimony, in combination with
other evidence such as the specific voltage output of
Cobos’s isolation stage, as substantial evidence underpin-
ning the Board’s decision. We agree with SynQor.
     “We defer to the Board’s findings concerning the cred-
ibility of expert witnesses.” Yorkey v. Diab, 601 F.3d
1279, 1284 (Fed. Cir. 2010).         The Board expressly
acknowledged Dr. Schlecht’s interest in the outcome of
the litigation and nevertheless found his testimony to be
“reasonable and largely unrefuted by persuasive evi-
dence.” J.A. 26. The Board also took into consideration
the evidence regarding Cobos’s 3.3-volt output and found
8                                VICOR CORP.   v. SYNQOR, INC.



that Cobos’s isolation stage was “generally regulated,” as
argued by SynQor. These fact findings by the Board
constitute substantial evidence which supports the
Board’s ultimate determination of nonobviousness.
Because Cobos is the only reference relied on to supply a
non-regulated isolation component in this proposed com-
bination, and because it does not disclose such a compo-
nent, the Board did not err in reversing the Cobos-
Pressman rejections.
                 II. Pressman-Kassakian
     Vicor argues that the Board erred as a matter of law
in holding that it would not have been obvious to combine
Pressman Figures 3-3 and 3-4(B) because the Board made
factual findings that ineluctably lead to a conclusion that
it would be obvious to combine the two figures. We agree
with Vicor on this point but, for the reasons below, hold
that the Board’s error on this issue was harmless. As
noted by SynQor, Figure 3-4(B) includes a pre-regulator
that renders the depicted embodiment a regulating
isolation stage. See J.A. 851–52. But Pressman contem-
plates removal of the pre-regulator under the facts as
found by the Board. Specifically, the Board found that
Figure 3-4(B) was “a modified version of Figure 3-4(A).”
This finding is supported by substantial evidence. See,
e.g., J.A. 851–52 (depicting Figure 3-4(B) as an extension
of Figure 3-4(A) and explaining modifications made to
Figure 3-4(A) to arrive at Figure 3-4(B)). This finding is
important because Pressman also states that the pre-
regulator in Figure 3-4(A), which is inherited by Figure 3-
4(B), is optional. J.A. 851 (“[E]ach post-regulator [i.e.,
switching regulator] can give adequately constant voltage
without pre-regulation and the cost and parts count of
the pre-regulator [in Figure 3-4(A)] can be saved.” (em-
phasis added)). Moreover, Pressman states that “[t]he
schemes of Figures 3-3 and 3-4 can be used with only one
transformer secondary winding and one filter capacitor to
generate a multiplicity of different output voltages at high
VICOR CORP.   v. SYNQOR, INC.                            9



efficiency as shown in Fig. 3-4(B)” and that “[t]his be-
comes possible by the use of switching post-regulators.”
J.A. 852. Thus, Pressman effectively discloses an alterna-
tive embodiment of Figure 3-4(B) which omits a pre-
regulator and adopts Figure 3-3’s front end. This alterna-
tive embodiment would be a non-regulating isolation
stage.
    Regarding the proposed incorporation of Kassakian’s
synchronous rectifiers into Pressman, Vicor argues that
the Board erred by requiring “‘bodily incorporation’” of
Kassakian’s synchronous rectifiers into Pressman. Open.
Br. at 46 (quoting In re Keller, 642 F.2d 413, 425 (CCPA
1981)). We disagree that the Board so required. The
Board instead opined that Vicor failed to prove that a
person of ordinary skill in the art would be able to incor-
porate controlled rectifiers into Pressman in view of
Kassakian. See J.A. 47. This finding is supported by
substantial evidence. Kassakian discloses experimental
synchronous rectifiers for use in a particular resonant
topology without any guidance as to how such rectifiers
could be modified for use in a square-wave circuit such as
Pressman’s. See J.A. 804 (Pressman disclosing square-
wave topology); J.A. 2021–23 (Kassakian disclosing exper-
imental resonant topology).       Dr. Schlecht, who co-
authored the Kassakian reference, explained in testimony
submitted to the Board that the Kassakian article “dis-
cussed advanced research” conducted by Drs. Kassakian
and Schlecht at MIT, and that the “technical discussions
therein were not directed to persons having ordinary skill,
but to persons highly skilled in the field.” J.A. 1335.
There is no evidence in the record that Kassakian’s syn-
chronous rectifiers would be transferrable to a square-
wave system. The Board was free to weigh the foregoing
evidence and determine that a person of ordinary skill
would not know how to combine Kassakian with Press-
man. Because this serves as an independent basis to find
the combination of Pressman and Kassakian non-obvious,
10                                 VICOR CORP.   v. SYNQOR, INC.



the Board’s error with respect to the combination of
Pressman Figures 3-3 and 3-4(B) was harmless, and we
affirm the Board’s ultimate decision on the Pressman-
Kassakian combination.
                        CONCLUSION
     The decision of the Board is affirmed.
                        AFFIRMED
                           COSTS
     No costs.
