7564702 et al.

Patent Trials and Appeals Board

Dec 18, 2020

2019004964 (P.T.A.B. Dec. 18, 2020)

UNITED STATES PATENT AND TRADEMARK OFFICE
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O. Box 1450
Alexandria, Virginia 22313-1450
www.uspto.gov
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
90/014,041 10/31/2017 7564702 X53716 4563
7055 7590 12/18/2020
GREENBLUM & BERNSTEIN, P.L.C.
1950 ROLAND CLARKE PLACE
RESTON, VA 20191
EXAMINER
NGUYEN, MINH T
ART UNIT PAPER NUMBER
3991
MAIL DATE DELIVERY MODE
12/18/2020 PAPER
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
PTOL-90A (Rev. 04/07)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________________

Ex Parte SYNQOR, Inc.
Patent Owner and Appellant
____________________

Appeal 2019-004964
Reexamination Control 90/014,0411
Patent No. US 7,564,7022
Technology Center 3900
____________________

Before JAMES T. MOORE, JOHN A. JEFFERY, and
DENISE M. POTHIER, Administrative Patent Judges.

MOORE, Administrative Patent Judge.

DECISION ON APPEAL

1 Request filed by Vicor Corporation (“Vicor” or “Requester”) on October
31, 2017.
2 Issued July 21, 2009 to Martin Schlecht and assigned to SynQor, Inc. (the
“’702 patent”). The ’702 patent issued from Application 11/901,263, filed
September 14, 2007 (“the ’263 Application”).

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STATEMENT OF THE CASE
Patent Owner SynQor appeals3 under 35 U.S.C. §§ 134(b) and 315(a)
(2002) from the rejection of claims 1–27, 55, 56, and 65–77 of U.S. Patent
7,564,702 (“the ’702 patent”) as set forth in the Final Rejection (“Final
Act.”) mailed September 12, 2018. The Examiner mailed an Examiner’s
Answer (“Ans.”) on March 20, 2019. The Patent Owner filed a Reply Brief
(“Reply Br.”) on May 20, 2019. Oral argument was conducted before a
panel of this Board on August 21, 2019,4 and a transcript of the proceedings
has been made of record. We have jurisdiction under 35 U.S.C. §§ 134 and
315.
The reexamination proceedings are related to a litigation filed against
Requester by Patent Owner in the Eastern District of Texas. See, e.g.,
SynQor, Inc. v. Vicor Corp., Civil Action No. 2:14-cv-00287-MHS-CMC
(E.D. Tex.) (hereinafter “the Texas Litigation”). The Texas Litigation is
said to be stayed pending the outcome of these reexamination proceedings.
The ’702 patent was successfully asserted against another party and
found to be not invalid. Damages were awarded, and the judgment
confirmed in SynQor, Inc. v. Artesyn Technologies., Inc., 709 F.3d 1365
(Fed. Cir. 2013) (hereinafter “SynQor I”).
On December 14, 2011, Vicor filed an inter partes reexamination
request (assigned Control No. 95/001,853, “the ’853 reexamination”) against
the ’702 patent (hereinafter “Request”). The Examiner finally rejected

3 SynQor’s Appeal Brief (“Appeal Br.”) was filed February 13, 2019.

4 Judge Siu has retired and is replaced on the panel by Judge Jeffery.

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claims 1–3, 12–20, 23, 26–30, 38–47, 50–56, 64, 67–76, 78, 80–82, 84–86,
88, and 89. After an appeal to the Board,5 the final rejection of claims 1–3,
12–20, 23, 26–30, 38–47, 50–56, 64, 67–76, 78, 80–82, 84–86, 88, and 89
was not sustained, and subsequently, the Court of Appeals for the Federal
Circuit6 affirmed that decision. The Examiner then presented a rejection of
certain claims in the Final Rejection mailed September 12, 2018.
We REVERSE the rejection of record.

THE ’702 PATENT
The ’702 Patent concerns power conversion. The claims generally
describe a two-stage direct current to direct current power conversion
system. The two stages are separate – one for isolation, and one for the
actual voltage conversions needed. The combination of these separate stages
is said to provide nearly lossless conversion. See ’702 Patent, Abstr.; 4:33
et. seq., and Figure 1.
As Patent Owner puts it, the ’702 patent power system is more
efficient (dissipating less power and heat), and smaller (taking up less space
on a load board) than the prior art systems. Appeal Br. 119. Conventional
wisdom, we are told, as regards then-existing distributed power architecture,
indicated that making converters smaller reduced efficiency, while

5 Appeal No. 2014-007362; the Board reversed all pending rejections in its
Decision of April 20, 2015.

6 _Vicor Corp. v. SynQor Inc., 2017 US. App. LEXIS 16599 (Fed. Cir. 2017)
(“Vicor II”). The Court affirmed the Board’s decision. Appeal Br. Ex. 13.

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increasing their efficiency made them larger. Id. Patent Owner states the
’702 patent solves this problem with its approach. Id. at 120.
According to Patent Owner, Dr. Schlecht took the isolating/regulating
board-mounted converters used in distributed power architecture systems,
split the isolation and regulation functions into two different “stages,” and
increased the efficiency of the isolation stage. Id.
This idea was said to be “radical” because, although multiple-stage
converters had been used many years earlier, the industry had largely
abandoned them as inefficient and wasteful of board space compared to
single-stage converters. Br. 119-120. Dr. Schlecht testifies that he realized
he could make a two-stage system that would be efficient and compact, and
would be especially suited for boards that needed multiple voltages. Id.,
citing Ex. 26, 9–10.
Substantial technical detail is provided on implementing the circuitry
of the invention, including the use of uncoupled transformers. ’702 Patent,
4:63–6:48. This detail further includes connecting the transformer windings
through metal oxide semiconductor field effect transistors (“MOSFETs”),
switching the transistors in a switching cycle to drive the waveform, and the
parallel controlled and uncontrolled rectifiers. Id.

THE CLAIMS
Claims 1 and 55 are illustrative of the claimed invention, and
reproduced below.
1. A DC-DC power converter system providing plural regulated DC
outputs, each having a regulated voltage, comprising:
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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 flowing 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:
i) at least one transformer that is not driven into saturation, the
at least one transformer having plural windings including at least one
primary winding and at least one secondary winding;
ii) plural power MOSFET switches in circuit with the at least
one primary winding, the plural power MOSFET switches causing
power to flow into the at least one primary winding;
iii) control circuitry coupled to the plural MOSFET switches,
the control 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
secondary 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 synchronization with a voltage waveform 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

c) plural non-isolating down-converter switching regulators, each
receiving power from the non-regulated, isolated DC output and each
providing one of the regulated DC outputs having a regulated voltage.

55. A DC-DC power converter system providing plural regulated DC
outputs, each having a regulated voltage, comprising:
a) a rectified source of power that is a DC input, the DC input
providing an input voltage;

b) a non-regulating isolating step-down converter through which
power from the DC input flows first before flowing through any regulation
stage, the non-regulating isolating step-down converter providing a non-
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regulated, isolated DC output having a non-regulated voltage and
comprising:
i) at least one transformer that is not driven into saturation, the
at least one transformer having plural windings including at least one
primary winding and at least one secondary winding;
ii) plural power MOSFET switches in circuit with the at least
one primary winding, the plural power MOSFET switches causing
power to flow into the at least one primary winding;
iii) control circuitry coupled to the plural MOSFET switches,
the control 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
secondary 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 synchronization with a voltage waveform 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

c) plural non-isolating down-converter switching regulators, each
receiving power from the non-regulated, isolated DC output and each
providing one of the regulated DC outputs having a regulated voltage.

EVIDENCE OF RECORD
The Examiner relies upon the following prior art in rejecting the
claims on appeal:
Abraham I. Pressman, Switching and Linear Power Supply Porwer
Converter Design, Hayden Book Company, New Jersey (1977).
(“Pressman”).

MOSPOWER Applications Handbook, Rudolf P. Severns, Ed.,
Siliconix, Inc. (1984). (“MOSPOWER”).

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THE REJECTION
Claims 1–27, 55, 56, and 64–77 stand rejected under 35 U.S.C.
§103(a) as obvious over Pressman in view of MOSPOWER.

GENERAL ISSUES
The Patent Owner asserts multiple prefatory issues concerning the
propriety of this reexamination. First, Patent Owner asserts that the Request
does not set forth a substantial new question of patentability. Appeal Br.
18–19. Second, the Appellant urges that this reexamination proceeding
should be dismissed under 35 U.S.C. § 325(d). Id. at 19–20.
As these issues could result in the merits decision being moot, we
address them first.
I. 35 U.S.C. § 325(d)
35 U.S.C. § 325(d) provides that:
Notwithstanding sections 135(a), 251, and 252, and chapter 30, during
the pendency of any post grant review under this chapter, if another
proceeding or matter involving the patent is before the Office, the
Director may determine the manner in which the post-grant review or
other proceeding or matter may proceed, including providing for the
stay, transfer, consolidation, or termination of any such matter or
proceeding. In determining whether to institute or order a proceeding
under this chapter, chapter 30, or chapter 31, the Director may take
into account whether, and reject the petition or request because, the
same or substantially the same prior art or arguments previously were
presented to the Office.

Patent Owner filed a Petition under § 1.181 on May 14, 2018 seeking
to have the Director exercise his discretion and reject the Request for ex
parte reexamination under 35 U.S.C. § 325(d), based upon the ’853
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reexamination. That Petition was denied by the Office of Patent Legal
Administration in a Decision mailed December 3, 2018.
In the decision denying the Petition, the Director stated that 35 U.S.C.
§ 325(d) allows the Director discretion to reject the request. Pet. 3. Among
other facts found by the Director is that the petition was filed long after the
proceeding was underway, even after a first office action on the merits. Id.
The Director denied the request as untimely. Pet. 4.
Patent Owner nevertheless urges that both for efficiency and to avoid
the possibility of inconsistent results, the issues should both be considered
by the Examiner and ultimately by the Board. Appeal Br. 47.
According to the Patent Owner, Requester pointed to the identical
figures and teachings in Pressman as used in the ’853 reexamination and
then used either Cobos or MOSPOWER to supplement the same missing
claim elements when requesting reexamination of the ’702 patent. In both
proposed grounds, Patent Owner states, the Requestor modified Pressman
Fig. 3-4B to meet the claim limitations recited in the ’702 patent by (i)
removing the pre-regulator (which precedes the isolation stage); (ii) inserting
the circuit of Pressman Fig. 2-1 into the block diagram of the modified Fig.
3-4B; and (iii) wholesale replacing the modified isolation stage of Fig. 3-4B
by using an isolation stage from a prior art figure (after first removing the
regulation function from each circuit), which serves to replace the diode
rectifiers of Fig. 3-4B with the claimed controlled or synchronous rectifiers
and to replace the primary side transistors Q1 and Q2 of Fig. 3-4B with the
claimed power MOSFETs. Appeal Br. 54–55.
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Patent Owner asserts that Requester intentionally chose not to make
these arguments until this late stage as “strategic behavior” which 35 U.S.C.
§ 325(d) was enacted to prevent. Appeal Br. 10.
We note that Section 325(d) is permissive in nature, indicating that the
Director “may” determine the manner in which the post-grant review or
other matter may proceed. In this instance, the Director decided the Petition
via the Office of Patent Legal Administration. The Director specifically
found that: (1) 35 U.S.C. § 325(d) does not require the Office to reject the
Request, (2) reexamination was ordered on December 6, 2017, well before
Patent Owner’s May 14, 2018 petition, and (3) Patent Owner’s May 14,
2018 petition was also filed after a non-final Office action had been mailed
on March 13, 2018, and after the Office conducted an interview on the
merits with Patent Owner on May 2, 2018. Petition Decision Dec. 3, 2018,
3. To quote the petition decision: “Accordingly, patent owner’s May 14,
2018 petition under 37 CFR 1.182 requesting the Office to exercise its
discretion pursuant to 35 U.S.C. 325(d) is denied as untimely.” Id. at 4.
(emphasis omitted).
We observe that the Director considered and decided the issue in a
manner of his choosing. We are provided no persuasive reasoning that the
procedure was inconsistent with the intent or language of the statute. Even
if the issues of patentability “should” be considered together for the sake of
consistency, such does not make the Director’s choice how to proceed in this
proceeding somehow erroneous. The Director has rendered his decision.7

7 See also Advanced Bionics LLC v. Med-El Elekromedizinische Gerate
GmbH, IPR2019-01469 (PTAB Feb. 13, 2020)(precedential). In the related
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Accordingly, and to the extent this may be an appealable issue, we are
not persuaded by this contention.

II. Substantial New Question of Patentability (“SNQ”)
An ex parte reexamination proceeding will not be ordered in the
absence of a substantial new question of patentability. 35 U.S.C. § 304;
Manual of Patent Examination Procedure (“MPEP”) § 2242.
For “a substantial new question of patentability” to be present,
it is only necessary that: (A) the prior art patents and/or printed
publications raise a substantial question of patentability regarding at
least one claim, i.e., the teaching of the (prior art) patents and printed
publications is such that a reasonable examiner would consider the
teaching to be important in deciding whether or not the claim is
patentable; and (B) the same question of patentability as to the claim
has not been decided by the Office in an earlier concluded
examination or review of the patent, raised to or by the Office in a
pending reexamination or supplemental examination of the patent, or
decided in a final holding of invalidity (after all appeals) by a federal
court in a decision on the merits involving the claim. If a
reexamination proceeding was terminated/vacated without resolving
the substantial question of patentability question, it can be re-
presented in a new reexamination request. It is not necessary that a
”prima facie” case of unpatentability exist as to the claim in order for
”a substantial new question of patentability” to be present as to the
claim. Thus, "a substantial new question of patentability" as to a
patent claim could be present even if the examiner would not
necessarily reject the claim as either fully anticipated by, or obvious in

reexamination appeal 2020-004156, the Director concluded in a petition
decision dated December 3, 2018 that this same art used in the same
argument fails the first prong of the test set forth therein; i.e. being
previously presented to the office. Consequently, we also find this result
consistent with the guidance therein and the Director’s previous decision.
Advanced Bionics at 8–9.
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view of, the prior art patents or printed publications. As to the
importance of the difference between “a substantial new question of
patentability” and a “prima facie” case of unpatentability see
generally In re Etter, 756 F.2d 852, 857 n.5, 225 USPQ 1, 4 n.5 (Fed.
Cir. 1985).
. . .
In a decision to order reexamination made on or after
November 2, 2002, reliance on old art does not necessarily preclude
the existence of a substantial new question of patentability that is
based exclusively on that old art. See Public Law 107-273, 116 Stat.
1758, 1899-1906 (2002), which expanded the scope of what qualifies
for a substantial new question of patentability upon which a
reexamination may be based. Determinations on whether a substantial
new question of patentability exists in such an instance shall be based
upon a fact-specific inquiry done on a case-by-case basis. For
example, a substantial new question of patentability may be based
solely on old art where the old art is being presented/viewed in a new
light, or in a different way, as compared with its use in the earlier
examination(s), in view of a material new argument or interpretation
presented in the request. Such material new argument or interpretation
may be based solely on claim scope of the patent being reexamined.
. . .
For any reexamination ordered on or after November 2, 2002,
the effective date of the statutory revision, reliance on previously
cited/considered art, i.e., "old art," does not necessarily preclude the
existence of a substantial new question of patentability (SNQ) that is
based exclusively on that old art. Rather, determinations on whether a
SNQ exists in such an instance shall be based upon a fact-specific
inquiry done on a case-by-case basis.
MPEP 2242.
Patent Owner asserts that the Request does not present any new, non-
cumulative, technological teachings not previously considered in previous
proceedings. Appeal Br. 22. Specifically, Patent Owner asserts that a prior
reexamination, 90/014,180 (“the ’180 reexamination”), addressed the same
issues. In that reexamination, it is stated, Requester relied on the identical
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figures as presented herein in MOSPOWER and Pressman for the same
technological teachings. Appeal Br. 10.
We observe that the Request itself stated that:

The Proposed Rejection is substantial, because “a reasonable
examiner would consider the teaching to be important in deciding
whether or not the claim is patentable.” MPEP § 2242. Indeed, the
Proposed Rejection presents a prima facie case of obviousness under
35 U.S.C. § 103(a). The description of the proposed rejection below
is incorporated by reference to support the “substantiality” portion of
the reexamination standard.
The Proposed Rejection is also new. There are two principal
references cited in the Proposed Rejection: Pressman and the
MOSPOWER Applications Handbook. The question of validity
over Pressman in view of the MOSPOWER Applications Handbook
has not been addressed, either in litigation or before the Office.

Request, 44 (footnote omitted).
The Requester further observed in the Request that, although
submitted in an information disclosure statement to the Office among
multiple other references, the MOSPOWER reference had never been cited
on the record in a rejection or proposed rejection, and not in combination
with another reference. Id., 44–45. This fact is not in dispute.
The Requester amplified upon the MOSPOWER reference’s new use
in the rejection – specifically, that Pressman as updated by the MOSPOWER
Applications Handbook discloses the features that Patent Owner has argued
were missing from the prior art in other proceedings. Id., 48. As stated by
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Requestor: “Although Pressman was examined in the ’1406[8] and ’1853[9]
reexaminations, it is presented here in a new light-namely in combination
with the MOSPOWER Applications Handbook. The MOSPOWER
Applications Handbook provides teachings that were not previously present
in combination with Pressman's alternative embodiment to Fig. 3-4B.” Id.,
49.
Patent Owner is of the view that this reexamination should not have
proceeded because, as noted above, the Office proceeded differently in
Reexamination the ’180 reexamination. Appeal Br. 18. We are not
persuaded by this argument, and note that the ’180 reexamination
proceeding eventually did move forward. Even were that not so, both
proceedings are presently in the same stage of appeal and judicial economy
is not served by stopping one of the proceedings at this time
Patent Owner is also of the view that this reexamination is a repeat of
the rejection based on Pressman and Cobos10 presented in the ’853
reexamination. Appeal Br. 19.
According to Patent Owner, the circuit from MOSPOWER Fig. 11(a)
used by the Request to combine with Pressman suffers from the same
regulation problem as Cobos— the output voltage of the isolation stages of

8 Reexamination Control No. 95/001,406, filed by Murata Manufacturing
Co., Ltd. On July 23, 2010.

9 Reexamination Control No. 95/001,853, filed by Vicor Corporation on
December 14, 2011.
10 J.A. Cobos & J. Uceda, “Low Output Voltage DC/DC Conversion,”
20th International Conference On Industrial Electronics, Control, and
Instrumentation 1676–1681 (1994). (“Cobos”).
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the circuits in Cobos and Fig. 11(a) of MOSPOWER are both regulated.
Appeal Br. 23.
The Examiner found that the combination of Pressman and
MOSPOWER Applications Handbook raises a substantial new question of
patentability to claims 1, 55, 67, and 71 of the ’702 patent. The Examiner
acknowledged that Pressman and MOSPOWER Applications Handbook
both were of record in the application leading to the ’702 patent, but also
found that the combination of Pressman and MOSPOWER Applications
Handbook was never applied to reject the claims or substantively discussed
during the prosecution of the ’702 patent. Determination 6.
The Examiner also observed that Pressman was also used in the ’1406
and the ’853 reexaminations but also found that Pressman was used in
combination with Kassakian,11 which is technically incompatible with
Pressman’s square wave converter. Id., 7.
The Examiner also found that Pressman was used in the ’853
reexamination, in combination with Cobos, which teaches a regulated
converter. Id.
The Examiner concluded that MOSPOWER Applications Handbook
teaches features that the Patent Owner had argued were missing from the
prior art, including a fixed 50% duty cycle that converts voltage levels
without regulation, and a square-wave non-regulating isolation stage that

11 John G. Kassakian & Martin F. Schlecht, High-Frequency High-Density
Converters for Distributed Power Supply Systems, 76 Proc. of the IEEE
(1988), pp. 362–76. (“Kassakian”).

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matches the isolation stage function of Pressman. The Examiner thus
determined there was a substantial new question of patentability. Id.
On the specific facts of this case, we are not persuaded that the
Examiner erred because he came to a different conclusion than another
branch of the Office did preliminarily in a related proceeding. The
Examiner pointed out the reasoning for finding a substantial new question,
e.g. that MOSPOWER describes a fixed 50% duty cycle, and while the
Patent Owner may disagree with it, we have not been pointed to reversible
error in finding an SNQ.
Accordingly, we are not persuaded of error.

THE SUBSTANTIVE REJECTION
The Rejection of Claims 1–27, 55, 56, and 64–77 under 35 U.S.C.
§ 103(a) as obvious over Pressman in view of MOSPOWER.

Claim 1 reads as noted above. The major components are summed up
for convenience here as (1) a DC input with variable input voltage, (2) a
non-regulating isolation step-down converter having inter alia, at least one
transformer, plural MOSFET switches, control circuitry, and plural
controlled rectifiers with parallel uncontrolled rectifiers, and (3) plural non-
isolating down-converting switching regulators.
Level of Ordinary Skill in the Art
The Petitioner states that the level of ordinary skill in the art is
adequately reflected by the following standard: a hypothetical person who,
would have a bachelor’s degree in electrical engineering and approximately
3–5 years of additional experience designing DC/DC converter and power
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supply systems. Dr. Patrizio Vinciarelli so testifies for the Requester. Ex.
10, ¶ 6.12 So does Dr. Schlecht.13 Ex. 45, ¶ 7.
We agree and find that the art of record supports such a determination.
Pressman
Pressman is a textbook that was “[w]ritten for both design engineer
and undergraduate with little or no knowledge of the power supply field and
the available design alternatives.” Request, 18, citing Pressman (Preface).
The Pressman textbook is divided into three parts: The first part
contains chapters 1 and 2, which describe basic building blocks for power
supply systems, such as DC/AC converters and switching regulators.
(Pressman, pp. 1–73). The second part is chapter 3, which describes how to
put the building blocks together to form a variety of power supply systems.
(Pressman, pp. 74–104). The third part contains chapters 4–9, which
describe in greater detail the construction of various building blocks.
(Pressman, pp. 105–365). Request 18–19.

12 Dr. Vinciarelli is CEO of Vicor Corporation. It could fairly be presumed
that he has an interest in the outcome of this proceeding. Ex. 10. Despite
this, we find him qualified to testify as to the technical subject matter of this
proceeding based upon his education and experience. Id., passim. We credit
his testimony as appropriate herein while acknowledging his potential bias.

13 Dr. Schlecht is the named inventor of the ’702 patent and Chief Executive
Officer of SynQor, Inc. It could fairly be presumed that he has an interest in
the outcome of this proceeding. See, e.g., Exs. 26, 45. Despite this, we find
him qualified to testify as to the technical subject matter of this proceeding
based upon his education and experience. Ex. 26, passim. We credit his
testimony as appropriate herein while acknowledging his potential bias.
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Pressman describes a number of systems that “resemble the
arrangement” of components in the claims of the ’702 patent. Request 19.
Figure 3-3, is reproduced below:

Requester asserts that Figure 3-3 has an “unregulated input converter”
(dc/dc converter). “The input converter is isolating, because it uses a
transformer (‘converter with multiple secondaries’). The outputs of the
converter lead to plural non-isolating down-converter switching regulators
(called ‘series switching postregulators’).” Accordingly, Requester asserts
that Pressman teaches a “single isolation stage to drive multiple regulation
stages.” Request, 19–20.
Figure 3-4 B is reproduced below:

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Figure 3-4 is a step block diagram of a preregulated converter
Pressman also states that Figure 3-3 can be used with only one
transformer secondary winding. Specifically, that “[t]he schemes of Figs. 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
efficiency as shown in Fig. 3-4B.” Pressman 83.
In other words, Requester asserts that Pressman describes a
combination of Figures 3-3 and 3-4B noted above, configured as having one
winding and filter, as illustrated below.
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The Figure is a Block Diagram of
Pressman’s Figures 3-3 and 3-4 B; Final Act. 4.

It bears noting that that more than one change is required to arrive at
this alternative embodiment. In addition to combining Figures 3–3 and 3–4,
the preregulator is removed from between the DC power source and
converter in Figure 3–4.
Our reviewing court has previously discussed the description of the
Pressman reference. In a prior decision on a related patent, the court
determined such a further embodiment exists, “an alternative embodiment of
Figure 3-4(B) which omits a pre-regulator and adopts Figure 3-3’s front end.
This alternative embodiment would be a non-regulating isolation stage.” See
Vicor Corporation v. SynQor, Inc., 2017 U.S. App. Lexis 16598 at *9–*11
(Fed. Cir. Aug. 30, 2017) (“Vicor II”) (Exhibit 13 to Appeal Brief, 4). We
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reference this embodiment as the “Pressman Alternative Embodiment” or
simply “alternative embodiment” hereinafter.
MOSPOWER
The MOSPOWER Applications Handbook is a 1984 textbook. The
Handbook is said to serve as “a source of detailed, up-to-date information on
device characteristics and circuit applications” of power MOSFETs.
MOSPOWER, p. xiii. As explained in the Handbook:
The book is divided into four sections. Chapters 1 through 3
discuss the basic operation of MOSFETs. Chapters 4 and 5
deal with the practical problems of using MOSFETs from a
device point of view. Chapter 6 is a collection of applications
examples selected to demonstrate how to use MOSFETs from a
circuit point of view. Chapter 7 provides an introduction to the
testing and reliability of MOSFETs.
Id.
In Chapter 5, MOSPOWER discusses using power MOSFETs in
rectification circuits. MOSPOWER explains that using power MOSFETs for
rectification will be more efficient than using diode rectifiers:
The efficiency penalty imposed by the offset voltage inherent in
Schottky and pn junction diodes has been a perennial thorn-in-
the-paw for designers of low voltage, high current power
supplies. Recent power MOSFET design advances allow
designers to economically replace Schottky diodes and provide
higher conversion efficiency in many applications. Using
power MOSFETs will remove that thorn.
Id., 5–69.
One figure of MOSPOWER is Figure 11(a) illustrating a DC-DC
converter. It is reproduced below:

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Figure 11(a) is a schematic diagram of a
DC-DC converter with multiple rectifiers.

Notably, the incoming voltage source is regulated by a pulse-width
modulator; the figures cited to us occasionally omit this.
The Rejection
Claim 1
A DC-DC power converter system providing plural regulated DC
outputs, each having a regulated voltage, comprising

The Examiner has found that Pressman discloses a power converter
system with a DC power source as shown in the Figure representing the
Pressman Alternative Embodiment, which as noted above is a combination
of Fig. 3-3 and Fig. 3-4B of Pressman. Indeed, the Examiner found this
finding to be mandated in the ’702 patent in Vicor II. See Final Act. 4.
Figures 3-3 and 3-4 B are reproduced below:

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Figure 3-3 and 3-4B are a diagram of
the Pressman Alternative Embodiment.

The Examiner has found that the Pressman Alternative Embodiment
has a non-regulating isolation stage, as illustrated below.

Final Act. 5. The Figure above is a diagram of a non-regulating isolation
stage.
According to the Examiner, the non-regulating isolation stage has a
transformer with a single secondary winding, followed by a rectifier and a
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filter. The Examiner thus concludes that Pressman teaches a DC-DC power
converter system providing unregulated output V1 and plural regulated DC
outputs V01, V02, and V03. Id.
a) a DC input providing an input voltage that varies over a range that
is more than plus or minus a few percent

The Examiner has additionally found that Pressman teaches a DC
input for providing an input voltage, shown in the Figure above with an
arrow. The Examiner has also found that Pressman states that the textbook
is directed to many different industries, including for communications,
computer equipment, and telecommunications applications.
The Examiner has further found that Pressman describes this in the
Preface. Id. at 6. The Examiner has also found that the input voltages are
often in the 36–75 volt range, and the output voltages are often 5V, 3.3V,
and 2.5V. Thus, the Examiner concludes that Pressman teaches an input
voltage that varies over a range that is more than plus and minus a few
percent. Id.
b) a non-regulating isolating step-down converter through which
power from the DC input flows first before flowing 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
The Examiner has further found that Pressman discloses a non-
regulating isolating converter through which power from the DC input flows
first before flowing through any regulation stage. The Examiner reasons
that the isolating converter is not regulated because Pressman teaches that
transistors are driven at a fixed 50% duty cycle. The Examiner has also
found that the non-regulating isolating converter shown in the Figure above
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is a step-down converter because Pressman teaches that the non-regulating
converter has input at least 10% above the highest of the output voltages. Id.
at 6, citing Pressman, 83.
The Examiner thus determines that Pressman teaches a non-regulating
isolating step-down converter through which power from the DC input flows
first before flowing through any regulation stage, the non-regulating
isolating step-down converter providing a non-regulated, isolated DC output
having a non-regulated voltage.
i) at least one transformer that is not driven into saturation, the at
least one transformer having plural windings including at least one primary
winding and at least one secondary winding

The Examiner has found that Figure 2-1 of Pressman teaches at least
one transformer having plural windings including at least primary winding
and at least one secondary winding. Figure 2-1 is reproduced below:

Figure 2-1 is an electronic schematic of
a primary transformer winding circuit.
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The Examiner has additionally found that Pressman teaches at least
one transformer that is not driven into saturation, because, as Pressman
explains, if transformers are driven into saturation, the result would be
excessive dissipation of power. Id. at 7, citing Pressman, pp. 58 and 63–64.
ii) plural power MOSFET switches in circuit with the at least one
primary winding, the plural power MOSFET switches causing power to flow
into the at least one primary winding
The Examiner has found that Figure 2-1 of Pressman discloses plural
switches 01 and 02 with the at least one primary winding, causing power to
flow into the at least one primary winding. Id. The Examiner concedes that
Pressman does not disclose that the illustrated switches 01 and 02 are power
MOSFET switches.
However, The Examiner finds that replacing the 01 and 02 NPN
bipolar transistors in Pressman (Q1 and Q2) that functioned as switches with
power MOSFET transistors would have been obvious to a person with
ordinary skill in the art. The Examiner specifically references the
MOSPOWER Applications Handbook as teaching a circuit in Figure 11(a),
at page 5-73, using power MOSFETs as switches on the primary side of a
transformer. Figure 11(a) is reproduced below:
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Figure 11(a) of MOSPOWER(Original) is a
circuit diagram of a current-fed converter.
The Examiner has concluded that it would have been obvious to a
person with ordinary skill in the art at the time the invention was made to
use the circuit taught in MOSPOWER to replace the bipolar Q1 and Q2
transistors in Pressman’s circuit. Id. at 8
As evidence thereof, the Examiner points to MOSPOWER explicitly
teaching the advantages of using the circuit. Specifically:
[t]he demand for low cost and high conversion efficiency is
fueling the overwhelming acceptance of switched-mode power
supplies (SMPS). To ensure cost-effective design of these
inherently high-efficiency supplies, switching frequencies must
rise. When MOSPOWER transistors are used as the switching
elements in a power supply, the 50 kHz frequency barrier
imposed by bipolar transistors is eliminated. Removal of this
barrier has allowed SMPS with operating frequencies up to 500
kHz to be constructed. At these higher frequencies, the size of
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the magnetic and capacitive components is decreased and the
switching losses are lower.
Id. at 8, quoting MOSPOWER, p 5-95 (emphasis omitted).
iii) control circuitry coupled to the plural MOSFET switches, the
control circuitry determining when the power MOSFET switches are turned
on and off in a switching cycle at a switching frequency; and
The Examiner additionally finds that the plural MOSFET switches
“inherently and obviously” require control circuitry. The control circuitry
causes 50% duty cycle voltage waveform to be applied to the gates of the
MOSFET switches. Id. at 9.

iv) plural controlled rectifiers in circuit with the at least one
secondary winding, each having a parallel uncontrolled rectifier
The Examiner has found that Figure 2-1 of Pressman discloses plural
diode rectifiers D1 and D2 in circuit with the at least one secondary winding.
Id.
The Examiner concedes that Pressman does not disclose plural
controlled rectifiers in a circuit with the at least one secondary winding, each
having a parallel uncontrolled rectifier, as called for in the claim. However,
the Examiner further finds that replacing D1 and D2 diodes functioned as
rectifiers in Pressman with power MOSFET transistors would have been
obvious to a person with ordinary skill in the art. Id.
The Examiner references the MOSPOWER Applications Handbook
teaching the circuit in Figure 11 (a), page 5-73, using power MOSFETs as
rectifiers on the secondary side of a transformer, concluding that it would
have been obvious to replace D1 and D2 in Pressman with controlled
rectifiers as taught in the MOSPOWER Applications Handbook for the same
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motivation discussed herein above with regard to replacing bipolar
transistors with power MOSFETs. Id.
each controlled rectifier being turned on for an on-state time and off
for an off-state time in synchronization with a voltage waveform of the at
least one primary winding to provide the non-regulated, isolated DC output,
The Examiner has additionally found that MOSPOWER Applications
Handbook teaches to turn each controlled rectifier ON for an ON-state time
and OFF for an OFF-state time, as shown in Figure 11(b) below, where the
V1 and V2 waveforms drive each controlled rectifier ON and OFF. Id., 10.
Interestingly, the Examiner finds that the voltage waveforms across all
the windings are synchronized because they are inductively coupled to one
another and the output of the controlled rectifiers provides a non-regulated,
isolated DC output because control voltages applied to switches 01 and 02
have 50 % cycle and it is inductively coupled. Id. at 10. This is an
important detail, operationally, as discussed further below.
Figure 11(b) is reproduced below:

MOSPOWER partial Figure 11(b) is
a graphical illustration of converter duty cycles.

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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
The Examiner has found that the non-regulating isolation stage of the
MOSPOWER Applications Handbook uses a fixed, 50% duty cycle in its
driving transistors. The Examiner explains that
[a]lthough the transition times in Fig. 11 (b) are not directly the
“transition times of the primary side voltage waveform”, they
are nonetheless representative of the transitions in the primary-
side waveform. This is so because the waveforms in Fig. 11 (b)
are driven by the circuit in Fig. 13, which uses auxiliary
secondary winding. The auxiliary secondary windings are
inductively coupled to the primary winding, and thus the
auxiliary secondary winding voltage waveform is the same as
the primary side voltage waveform. Thus, the duty cycle,
frequency and relative length of the transition times of the
primary-side voltage waveform are reflected in Fig. 11 (b).
Id. at 11.
c) plural non-isolating down-converter switching regulators, each
receiving power from the non-regulated, isolated DC output and each
providing one of the regulated DC outputs having a regulated voltage.
The Examiner has found the plurality of non-isolating switching
regulators are shown in Pressman Figure 3-4. Id. at 11.
The Examiner sums up the rejection thusly:
In summary, Pressman teaches most of the limitations
recited in claim 1. Pressman differs in two primary respects,
both within the "non-regulating isolating step-down converter".
First, Pressman does not use power MOSFETs as its driving
transistors Q1 and Q2. Second, Pressman does not use
controlled rectifiers, but instead uses diode rectifiers. Both of
these differences, however, were simply due to the age of
Pressman. Power MOSFET transistors became widely-used
after Pressman’s publication, and were generally superior to
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bipolar transistors for power conversion applications. Thus,
replacing these elements with power MOSFETs is obvious
because they are generally superior to bipolar transistors and
diodes.
Id. at 12.
The Appeal
The Patent Owner asserts, among other alleged errors, that the
Examiner’s proposed simple substitution of (i) the switches Q1 and Q2
disclosed in Pressman for the power MOSFET switches from MOSPOWER
Fig. 11(a) and (ii) diode rectifiers Dl and D2 in Pressman for MOSFET
controlled rectifiers on the secondary side of the transformer from
MOSPOWER Fig. 11(a) would not work. Appeal Br. 59–63. More
specifically, Appellant urges that the circuit does not work because the
power MOSFETs cannot turn off because the voltage across the secondary
and auxiliary windings cannot change. Id., 64.
We are provided the testimony of Dr. Martin F. Schlecht, Sc. D. in
support of these contentions. Ex. 45 ¶ 1. Dr. Schlecht is an inventor of the
’702 patent, and as noted before, he has an interest in this proceeding as
Chief Executive Officer of SynQor, Inc. Id. ¶ 1. We acknowledge that this
fact reduces the probative value Dr. Schlecht’s declaration somewhat. See
Ashland Oil, Inc. v. Delta Resins & Refractories, Inc., 776, F.2d 281 (Fed.
Cir. 1985) (noting that an expert’s interest in the outcome of the case is a
factor in assessing the probative value of an expert opinion).
Dr. Schlecht testifies that isolation stage created by the Examiner
results in a stalemate or a “catch 22” because the synchronous rectifiers are
not able to turn off at the end of a half cycle because the voltage across the
secondary and auxiliary windings must first be changed. He states that these
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transformer windings’ voltages cannot be changed unless and until the
synchronous rectifier is first turned off. Ex. 45, ¶¶ 16–27. The
consequences of this are said to be a short circuit and potential destruction of
components. Id. ¶ 27. Appellant does not point out where Dr. Schlecht
testifies as to whether one of ordinary skill in the art would know how to
solve this problem or not.
The Examiner states in response that
PO appears to argue that capacitors at the outputs of Fig. 2-1 of
Pressman and Fig. 11 (a) of MOSPOWER Applications Handbook
have different values and therefore the replacement does not work.
The Examiner notes a POSA is not an automation, he would know
how to adjust the value. This capacitor and its value are not in the
claim. If they were important features and not obvious to a POSA[14],
the claim and even the specification of the ’702 patent which is under
this reexamination, would have had to disclose, but they are not. The
same is true for the ‘dot’ argument from the PO, a POSA in the
related art would know the relative polarities of the various windings
in the circuit; otherwise, this feature is a critical element, it
Application/Control Number: 90/014,041 must be recited in the claim,
however, it is not. The Examiner submits that PO presents arguments
that are irrelevant because they are not in the claim.

Ans. 24–25.

We find this conclusory statement about the inoperativeness of the
combination unhelpful. We reach this conclusion especially if, as Appellant
states, “the resulting circuit is both inoperative and fails to meet the claim
limitations at least because the synchronous rectifiers are not controlled or
effecting rectification, yet decline to explain how a POSA would both be

14 Person of Ordinary Skill in the Art at the time the invention was made.
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able to recognize and solve the problem based on prior art printed
publications or patents.” Appeal Br. 65–66.
On the other hand, we are cognizant that “the test for obviousness is
not whether the features of a secondary reference may be bodily
incorporated into the structure of the primary reference; nor is it that the
claimed invention must be expressly suggested in any one or all of the
references. Rather, the test is what the combined teachings of the references
would have suggested to those of ordinary skill in the art.” In re Keller, 642
F.2d 413, 425 (CCPA 1981). Further, “a determination of obviousness
based on teachings from multiple references does not require an actual,
physical substitution of elements.” In re Mouttet, 686 F.3d 1322, 1332 (Fed.
Cir. 2012) (emphasis added).
Moreover, we are aware that the artisan is not compelled to follow
blindly the teaching of one prior art reference over the other without the
exercise of independent judgment. See Lear Siegler, Inc. v. Aeroquip Corp.,
733 F.2d 881, 889 (Fed. Cir. 1984).
We are further mindful that the skilled artisan would “be able to fit the
teachings of multiple patents together like pieces of a puzzle” because the
skilled artisan is “a person of ordinary creativity, not an automaton.” KSR
Int'l Co. v. Teleflex Inc., 550 U.S. 398, 420–21 (2007).
However, in this instance, the Appellant is asserting that the
Examiner’s proffered combination would have been “uniquely challenging
or difficult for one of ordinary skill in the art.” Leapfrog Enters., Inc. v.
Fisher-Price, Inc., 485 F.3d 1157, 1162 (Fed. Cir. 2007) (citing KSR, 550
U.S. at 418).
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Dr. Vinciarelli, in his Declaration filed with the Request, testifies that
“[i]t would have been obvious to use this non-regulating isolation stage as
the non-regulating isolation stage in the alternative embodiment to Fig. 3-4B
of Pressman.” Vinciarelli Decl. ¶ 35.
The substitution would be as follows:

Ex. 10, ¶ 35.
We are not persuaded that it is quite as simple a substitution as both
the Examiner and Dr. Vinciarelli posit, for the reasons that follow later in
this decision, and especially in view of Dr. Schlecht’s testimony that the
circuit does not work and the detailed instructions in the Specification of the
’702 patent.
First, Appellant asserts the ’702 patent describes a way to solve the
problem posed by the circuit described in the rejection,- which has a single
transformer where the primary, secondary and auxiliary windings are tightly
coupled. Appellant asserts that by using two separate (uncoupled)
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transformers, with the gate drive of each synchronous rectifier being derived
from a winding on the other transformer, a workable circuit is made. Appeal
Br. 67.
More specifically, Appellant notes that the first transformer has its
secondary winding connected to the first synchronous rectifier, but the gate
of the first synchronous rectifier is driven by a winding on the second
transformer. Id.
We are especially persuaded by the text of the ’702 specification,
which states:
Notice also the benefit of using two, uncoupled transformers.
The voltage across a first transformer can be changed, causing the
channel of the MOSFET synchronous rectifier transistor connected to
a second transformer to be turned off before the voltage across the
second transformer is made to change. This could not be done if both
primary and both secondary windings were tightly coupled in the
same transformer since the voltages across all the windings would
have to change together.

’702 patent, 7:45–53.
Appellant further urges that the ’702 patent provides additional details
of the transition, showing (1) how complicated the issue is; (2) how solving
the problem requires an understanding of parasitic capacitances and leakage
inductances and how they interact with each other; and (3) how the timing of
the operation of the primary side transistors depends on this understanding.
Appeal Br. 68, citing ’702 patent, 7:54–10:4.
The Examiner’s Answer states that:
PO raises issues that circuits shown in Fig. 2.1 of Pressman
and in Fig. 11 (a) of MOSPOWER Applications Handbook do not
operate the same because other components are different. However,
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this is not the point in this rejection. The point is whether it is obvious
to replace bipolar transistors, functioned as switches, with
MOSPOWER transistors. Fig. 11 (a) of MOSPOWER Applications
Handbook shows that it is obvious because more than a year before
the application of the ’702 patent, there existed at least a reference
that teaches such an idea.

Ans. 28.
Further:
The replacement is easy because this is a well-known practice
as MOSPOWER transistor characteristics are well-known to a person
with ordinary skill in the art.

Id., 29.
These statements are somewhat conclusory in our view, and do not
explain the issue as to why one of ordinary skill in the art would be
motivated make such a change when such a modification would be
inconsistent with the functioning of the reference, let alone explain how the
modifications that are purportedly “well-known” or would arrive at
characteristics well-known to one of ordinary skill in the art. Neither the
Requester nor the Final Rejection persuasively dealt with the operational
complexities of synchronous rectification.
Patent Owner also asserts that the rejection uses the claim to pluck the
needed elements from “the sea of prior art.” Appeal Br. 69–70.
More specifically, Patent Owner urges that the rejection takes “two
very large and substantial textbooks (each several hundred pages long) and
selectively extracts, using the claim limitations as the guide, the component
parts needed to meet the claim limitations.” Id., 70. We find this argument
somewhat compelling.
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First, we observe that the rejection requires an amended construct to
arrive at Pressman Figure 3-4B. The Request starts with Pressman’s Figure
3-3, which is a straightforward unregulated isolating input converter having
multiple windings with post-regulated outputs. Request 19. The Request
then picks one of those embodiments – only one transformer secondary
winding – and creates Pressman modified Figure 3-3. Id., 20. But the
modifications are not yet done: the pre-regulator must also be removed. Id.,
21. Support for this is found within Pressman that the pre-regulator is
optional. Pressman, 82. We are of the view that, with these selections,
Pressman in fact describes a further modified Figure 3-3.
Pressman, however, also teaches that including the preregulator makes
a two-transistor push-pull dc/ac converter useable. Id., 82–83. The Request
notes that both Pressman and MOSPOWER use push-pull configurations.
Id., 67. Several reasons are proffered for removing the preregulator,
including it would be made “to match Pressman’s architecture” (Id., 66); and
that the court found the pre-regulator in Pressman to be optional. (Id., 67.).
.
The Final Rejection proposes to substitute MOSPOWER transistors
for Pressman’s rectifiers. The reasoning is that:
The MOSPOWER Applications Handbook further
explicitly teaches advantages of using this circuit as follow.
“The demand for low cost and high conversion efficiency
is fueling the overwhelming acceptance of switched-mode
power supplies (SMPS). To ensure cost-effective design
of these inherently high-efficiency supplies, switching
frequencies must rise. When MOSPOWER transistors are
used as the switching elements in a power supply, the 50
kHz frequency barrier imposed by bipolar transistors is
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eliminated. Removal of this barrier has allowed SMPS
with operating frequencies up to 500 kHz to be
constructed. At these higher frequencies, the size of the
magnetic and capacitive components is decreased and the
switching losses are lower.”
(MOSPOWER Applications Handbook, p 5-95).

Final Act. 8. Further:
However, replacing D1 and D2 diodes functioned as rectifiers
in Pressman with power MOSFET transistors would have been
obvious to a person with ordinary skill in the art. For example, the
MOSPOWER Applications Handbook teaches a circuit in Fig. 11 (a),
page 5-73, using power MOSFETs as rectifiers on the secondary side
of a transformer. It would have been obvious to replace D1 and D2 in
Pressman with controlled rectifiers taught in the MOSPOWER
Applications Handbook for the same motivation discussed herein
above with regard to replacing bipolar transistors with power
MOSFETs.

Id.
Thus, ultimately, the rationale for creating the construct, and replacing
the diodes of the modified construct with MOSFETs, is the use of these
transistors will increase efficiency at low cost, reduce size, and permit higher
frequencies.
Patent Owner, on the other hand, asserts that the level of skill in the
art and the state of the art would have guided one of ordinary skill in the art
away from the claimed combination. Appeal Br. 36.
Most persuasively, as discussed above, the circuit as proposed and
arranged in the rejection would not work. Dr. Schlecht testifies that the
output capacitor in the construct will keep the voltage across the top
secondary winding positive and the voltage cannot transition from positive
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to negative without turning off the top synchronous rectifier. Ex. 45 ¶ 25.
As a result, he testifies, “[t]he top synchronous rectifier (S1) is not able to
transition to the ‘off’ state until the top auxiliary winding voltage is no
longer positive. The positive voltage across the top auxiliary winding is
what keeps the top synchronous rectifier (S1) in the ‘on’ state.” Id. ¶ 56.
This results in an impossible stalemate. The Rejection
[Isolation] Circuit is not working as intended. It would likely
remain in this state until the output voltage collapses due to the
short circuit currents that will flow. The currents could be large
enough to damage or destroy the components in the circuit.
Id. ¶ 57. We find this testimony credible and persuasive.
We look to Dr. Patricio Vinciarelli’s declaration to see his point of
view on making the combination. Like Dr. Schlecht, we find him to be
competent to testify as to the technical subject matter of this proceeding. Ex.
10, ¶ 2.
Dr. Vinciarelli testifies that “[a] person of ordinary skill would
understand how to drive Ql BASE and Q2 BASE with control circuitry. The
waveforms have a switching cycle, which is simply the duration between
two high ➔ low transitions or two low ➔ high transitions . . . .” Id. ¶ 17.
He further notes that:
A person of ordinary skill would understand from Fig.
11(a) and 11(b) that the primary side switches are driven with
complementary, alternating 50% duty cycle square waveforms,
. . . across the primary windings, and corresponding waveforms
across the secondary windings. Each power MOSFET switch
would therefore switch at the same frequency, which is the
inverse of the switching cycle, as explained in ¶ 17, above. The
switching cycle is divided between times when primary power
MOSFET and corresponding secondary controlled rectifiers are
ON, and times when they are OFF.
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Id. ¶ 29.
Dr. Vinciarelli also testifies as to some of the design choices to be
made when fabricating the circuitry, for example, distinguishing between
voltage-fed and current-fed converters and the use of inductors. One telling
bit of testimony is that “[p]roper sizing of an inductor for a current-fed
topology was well within ordinary skill, and the choice between current-fed
and voltage-fed converters was a design choice that could be made within
ordinary skill.” Id. ¶ 33.
Further, he observes that:
Pressman states that the components in the systems of Chapter
3 are meant to be modular: “All these requirements can be met
with different combinations and permutations of the above
basic building blocks. Systems can be devised with standard
electrically and mechanically configured building blocks
requiring only a minimum custom circuit change to fit a large
variety of applications.” (Pressman, p. 74). A person of
ordinary skill would have understood this to mean that blocks
within Pressman’s block diagrams could be modularly replaced,
and that such replacements required only minimal skill.
Id. ¶ 38.
We are generally persuaded by the Requester and Examiner that one
of ordinary skill could implement certain changes and adaptations, but we
are left with the fact that the resulting capacitor in the construct observed by
Dr. Schlecht renders the circuit inoperative. Neither the Requester nor the
rejection noticed or dealt with that problem effectively.
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Indeed, it appears that the Requester intentionally wired the controlled
rectifiers together as noted above in the Final Rejection’s combination,15
which is the heart of the incompatibility problem solved by SynQor’s work.
Id. ¶ 39. Consequently, we agree with Patent Owner that the proposed
construct would require additional modifications to effectuate the claimed
arrangement, and also find that arriving at the claimed arrangement is not a
simple substitution as implied by the Examiner and Dr. Vinciarelli. We
agree with Patent Owner that “[t]he failure of the [circuit] to work as
intended . . . demonstrates the complexity of utilizing synchronous
rectification . . . .” Appeal Br. 82–83.
Patent Owner points out the technical complexity by referencing the
’702 patent itself, which we find very persuasive, including providing
detailed and lengthy teachings to solve the problem by using two separate
(uncoupled) transformers, with the gate drive of each synchronous rectifier
being derived from a winding on the other transformer. In other words, the
inventor provided a detailed explanation as to how to make the non-working
circuit work. Id.
More specifically, an example is provided when the first transformer
has its secondary winding connected to the first synchronous rectifier, but
the gate of the first synchronous rectifier is driven by a winding on the
second transformer. Id.
The ’702 patent specifically notes:

15 [T]he windings are synchronized because they are inductively coupled to
one another and the output of the controlled rectifiers provides a non-
regulated, isolated DC output because control voltages applied to switches
01 and 02 have 50 % cycle and it is inductively coupled. Final Act. 10.
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Notice also the benefit of using two, uncoupled
transformers. The voltage across a first transformer can be
changed, causing the channel of the MOSFET synchronous
rectifier transistor connected to a second transformer to be
turned off, before the voltage across the second transformer is
made to change. This could not be done if both primary and
both secondary windings were tightly coupled in the same
transformer since the voltages across all the windings would
have to change together.
’702 patent, col. 7, ll. 45–53.
We find the reliance of the rejection on the fact that the ’702 patent
made the circuit work to be particularly unpersuasive. Final Act. 22–23;
Ans. 25–26. We shall not use the inventor’s own work against him. In any
event, the Final Rejection’s statement that “PO is clearly contradict[ing]
himself when arguing that the replacement of D1 and D2 in Pressman with
MOSPOWER transistors shown Fig. 11(a) in MOSPOWER Applications
Handbook proposed in the rejection by the Examiner would not work
whereas the replacement disclosed in the ’702 patent, i.e., replacing D1 and
D2 shown in Fig. 2 with MOSP[O]WER transistors shown in Fig. 4 would
work” (Ans. 24) does not accurately reflect that the two circuits are different
in one major aspect – the two transformers in the embodiments of the ’702
patent are uncoupled.
Patent Owner next urges that a person of ordinary skill in the art
would not be motivated to use the isolation stage of MOSPOWER Figure
11(a) as a starting point because it is incompatible with Pressman
Alternative Embodiment. Appeal Br. 96.
More specifically, Patent Owner asserts that the circuit in
MOSPOWER Fig. 11(a) is a converter with a regulation stage followed by
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an isolation stage, where the output voltage of the isolation stage is
regulated. That output voltage is regulated by sensing its output voltage,
comparing it to a desired value, and feeding the error back through a control
loop to vary the duty cycle of the pre-regulator which is pulse-width
modulation controlled. Id. at 96–97.
Appellant further points out that the Pressman circuits are configured
such that the pre-regulator is controlled to regulate its own output voltage
which feeds the isolation stage. Schlecht Dec. ¶ 32–35. In contrast, Dr.
Schelcht testifies that Fig. 11 of MOSPOWER illustrates a two-stage
converter with the output voltage of the isolation stage being regulated using
a pre-regulator. Id. In other words, each pre-regulator regulates a different
output and they are not equivalent, even if they are located similarly.
We tend to agree with the Patent Owner that the overall logic for
removing the MOSPOWER pre-regulator—that Pressman somehow
recommends pre-regulation be removed—is faulty. This also tends to weigh
against the conclusion of obviousness.
We also are persuaded by the Patent Owner’s observations that the
complexity of providing synchronous gate drives is a reason that one of
ordinary skill in the art would further not have made the combination.
Appeal Br. 100.
Accordingly, we conclude that the combination of Pressman and
MOSPOWER alone does not establish a prima facie case of obviousness.
We further observe that there is some additional and compelling
objective evidence found in the record that further supports the above
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finding that SynQor’s success in solving the challenge discussed above was
significant.
For example, in the infringement action SynQor I, a competitor,
Artesyn, was found to have sold products that were found to have infringed
claims 2, 3, 7, 8, 10, and 19 of the ’702 patent. Reply Br. 13–14. The
evidence underlying that judgment involved evidence of significant
skepticism and praise from a direct competitor for products infringing at
least claims 2, 8, and 19 (Appeal Br. 84):
Q. Was there initial skepticism or surprise in the field to Dr.
Schlecht’s claimed IBA inventions?
A. Yeah. One of the issues you have when you try and put two
converters in series, the conventional wisdom is that, you know, your
efficiency is always going to be less, because you take this efficiency,
and you put another one, and you multiple the two efficiencies
together. They’re always less than one, and so that ultimate number is
always usually smaller. But in this invention, the way he’s done it,
he’s got that isolation stage so efficient, that that number starts
approaching one. And so even if you multiply it by another number
here in series with that, you still wind up with a pretty efficient
system, comparable or better even in some cases I’ve seen.

Testimony of Mr. Mark Rice, Vice President of Artesyn Corporation,
defendant in SynQor I. Ex. 25-98, 168:16-169:5.
That same competitor acknowledged the difficulties in implementing
the invention of the ’702 patent.
Exhibit 25-49 is particularly informative when viewed in terms of
competitors developing a “second source” to SynQor:
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We find the powerful third party testimony and evidence in the record
further supports a conclusion that Pressman and MOSPOWER would not
have rendered the claimed subject matter obvious to one of ordinary skill in
the art.

CONCLUSION
We have carefully considered the evidence of record. We also have
considered the evidence submitted by the Requester and the findings and
conclusions of the Examiner.
The weight of the objective evidence, combined with the technical
difficulties in implementing the proposed combinations of references
adopted from the Request by the Examiner, lead us to the conclusion that
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the claims at issue would not have been obvious to one of only ordinary skill
in the art at the time the invention was made.
The record does not establish that claims 1–27, 55–56, and 64–77
would have been obvious to one of ordinary skill in the relevant art at the
time of the effective date of the ’702 patent invention.
We, therefore, do not sustain the obviousness rejection of these
claims.

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DECISION
The rejection of claims 1–27, 55–56, and 64–77 under 35 U.S.C.
§ 103(a) as obvious over Pressman in view of MOSPOWER is reversed.
In summary:
Claims
Rejected
35 U.S.C.
§
Reference(s)/Basis Affirmed Reversed
1–27, 55–
56, 64–77
103 Pressman,
MOSPOWER
1–27, 55–
56, 64–77

REVERSED

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PATENT OWNER:

GREENBLUM & BERNSTEIN, PLC
1950 Roland Clarke Place
Reston, VA 20191

THIRD PARTY REQUESTER:

SMITH BALUCH LLP (GENERAL)
100 M Street SE, Suite 600
Washington, DC 20003