Ex Parte 6,191,964 et al

Patent Trial and Appeal Board

Sep 9, 2013

95001231 (P.T.A.B. Sep. 9, 2013)

UNITED STATES PATENT AND TRADEMARKOFFICE
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.
95/001,231 09/11/2009 6,191,964 1465.0013-002 6313
7590 09/10/2013
GLENN W. BOISBRUN
HITT CHWANG & GAINES, P.C.
P.O. BOX 832570
RICHARDSON, TX 75083
EXAMINER
NGUYEN, LINH M
ART UNIT PAPER NUMBER
3992
MAIL DATE DELIVERY MODE
09/10/2013 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
________________

SynQor, Inc.
Requester

v.

Lineage Power Corporation
Patent Owner

________________

Appeal 2013-000148
Inter Partes Reexamination Control No. 95/001,231
Patent US 6,191,964
Technology Center 3900
________________

Before KARL D. EASTHOM, KEVIN F. TURNER and GLENN J. PERRY,
Administrative Patent Judges.

PERRY, Administrative Patent Judge.

DECISION ON APPEAL

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I. BACKGROUND AND SUMMARY
A. Procedural History
This is an appeal from an Examiner decision in an inter partes
reexamination of US Patent No. 6,191,964 (the '964 patent),
1
owned by Lineage
Power Corporation (“Patent Owner”). The '964 patent issued in 2001 with claims
1-40. SynQor, Inc. (“Requester”) requested reexamination,
2
which was granted.
3

During the course of reexamination, claims 41-59 were added.
4
Claims 50-59 were
later cancelled. After an action closing prosecution (ACP), the Examiner issued a
Right of Appeal Notice (“RAN”).
5
The RAN lists claims 1-9, 11-19, 21-28, 30-39,
41-44 and 46-49 as being unpatentable based on various grounds. The RAN also
indicates that claim 45 is patentable (see RAN 25) and that claims 10, 20, 29 and
40 are not subject to reexamination. Claims 1, 11, 21, 31, 45 and 46 are the
surviving independent claims. Claims 1-9, 11-19, 21-28, 30-39, 41-44 and 46-49
are rejected. Patent Owner invokes our review of rejected claims under
35 U.S.C. § 134(a). Requester invokes our review in a cross-appeal asking that we
reverse the Examiner’s decision not to adopt various Requester proposed SNQs.
6

We have jurisdiction under 35 U.S.C. §§ 134 and 315.
B. Related Litigation and Appeals
Both Appellant and Third Party Requester have identified the following

1
This matter is among those in a “pipeline” of inter partes reexaminations that
were initiated prior to the America Invents Act’s (AIA) termination of filing of
new inter partes reexamination requests.
2
Request for Reexamination filed September 11, 2009.
3
Reexamination was ordered on October 23, 2009.
4
See RAN page 2.
5
Right of Appeal Notice (RAN) dated November 19, 2010.
6
Substantial New Question (SNQ) of Patentability proposed by Requester in Inter
Partes Reexamination Request filed September 11, 2009.
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related action involving the '964 patent:
Lineage Power Corporation v. SynQor, Inc., Civil Action No. 2:08-
cv-95(TJW/CE) in the United States District Court for the Eastern
District of Texas, Marshall Division.
C. The '964 Patent Invention
The invention described in the '964 patent provides “a control circuit for
operating a power rectifier in bidirectional and unidirectional modes of operation
as a function of a characteristic of the power system.” '964 patent 1:33-36.
Operation in only a bidirectional mode is described as being problematic.
The bidirectional current flow characteristic allows
inductor current in the synchronous rectifier circuit to
flow continuously, thereby avoiding a sluggish reaction
to a load or transient on the output of the converter
circuit.

However, for converters connected in parallel with
forced load-sharing, this bi-directional power flow
characteristic can result in an undesirable (and possibly
damaging) operating mode wherein one converter drives
the output of another.

'964 patent 2:45-53. To provide the capability to operate in both bidirectional and
unidirectional modes, the invention provides
control circuitry [that] is capable of sensing an output
level of the rectifier and transitioning switching circuitry
between the bidirectional mode and the unidirectional
mode as a function of the output current level to prevent
substantial reverse power flow through the rectifier.

'964 patent 4:12-16.
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A synchronous rectifier is disabled selectively, based on a measured
characteristic of the power converter, to prevent “substantial reverse power flow.”
Id. at 15-16. Figure 3 of the '964 patent, reproduced below, shows an embodiment
illustrating one way that control is accomplished.

'964 Patent Figure 3
A current sense signal at node 365 represents a “condition” that triggers
control of rectifiers (SR1, SR2). A load current level detector 375 compares the
sensed current to a reference level. An output “enable/disable” signal from load
current level detector 375 is input to an SR control unit 350, which controls silicon
rectifier SR1. See '964 patent 3:53-4:10. Another embodiment of the invention is
shown in Figure 5 of the '964 patent, reproduced below.
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'964 patent Figure 5
Fig. 5 shows a non-isolated buck converter ("buck converter") 500 having a
synchronous rectifier circuit 510. This embodiment includes the addition (with
respect to Fig. 4 prior art) of control circuitry 520 and switching circuitry including
switch Q2. To prevent bidirectional power flow, switch Q2 is disabled by control
circuitry 520, triggered by a sensor or timer 530. The rectifier transitions from
operation in a bidirectional mode to operation in a unidirectional mode by
disabling switch Q2 (analogous to disabling synchronous rectifier device SRI in
FIG. 3). Bidirectional power flow is prevented by replacing switch Q2 with a
diode or by disabling switch Q2 and relying on its body diode. See '964 patent 9:4-
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26. Patent Owner draws a distinction between “instantaneous” and “average”
reverse power flow” as follows:

When considering reverse power flow in a synchronous
rectifier, it is important to understand the distinction between
instantaneous and average reverse power flow. Instantaneous
reverse power (or inductor current) flow may be defined as
negative power (or current) flow for only a portion of each
switching cycle. The current does not remain negative for an
entire switching cycle. Average reverse power (or inductor
current) flow may be defined as a net negative current averaged
over more than one switching cycle. During a start-up or shut-
down transient, for example, average negative current could be
maintained for several switching cycles prior to the current
settling out in steady state, but need not remain negative
continuously.

'964 patent 9:34-46.
D. Prior Art
The prior art relied upon by the Examiner is listed below.

Loftus U.S. Patent 5,036,452 July 30, 1991
Yamamura U.S. Patent 5,233,508 August 3, 1993
Zimmermann U.S. Patent 5,237,606 August 17, 1993
Rozman U.S. Patent 5,303,138 April 12, 1994
Milavec U.S. Patent 5,636,116 June 3, 1997
Dittli U.S. Patent 5,663,877 September 2, 1997

Nobuhiko Murakami et al., "A Highly Efficient, Low-Profile 300-W Power Pack
for Telecommunications Systems," IEEE 0-7803---111456-5/94 786, 876-972
(APEC 1994) ("Murakami I").
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Raymond Orr, "An Implementation of Synchronous Rectifiers in a Power
ConverterDesigned for use in Parallel Operation," Power Conversion Conference,
October 1990 ("Orr 1990").

Nobuhiko Murakami et al., "A Compact, Highly Efficient 50-W On-board
PowerSupply Module for Telecommunication Systems," 0-77803-2482-X/95 297
(APEC 1995)
E. Examiner Adopted Rejections
7

The RAN lists the following rejections made by the Examiner. We
denominate them for convenience as they are denominated in the PO App. Brief
8
at
pages 7-9:
(A) Claims 1, 2, 4, 5, 8-9 and 43-44 are anticipated by Dittli.
(B) Claims 11-12, 14-15 and 18-19 are anticipated by Dittli.
(C) Claims 21-24, 27-28 and 30 are anticipated by Dittli.
(D) Claims 3 and 13 are obvious over Dittli.
(E) Claims 6, 16 and 25 are obvious over Dittli in view of US Patent No. 5,036,452
to Loftus (hereinafter "Loftus").
(F) Claims 7, 17 and 26 are obvious over Dittli in view of Rozman.
(G) Claims 7, 17,26 and 42 are obvious over Dittli in view of Mi1avec.
(H) Claims 41 and 42 are obvious over Ditt1i in view of Orr.
(I) Claims 42 and 47-49 are obvious over Dittli in view of Yamamura.
(J) Claims 47 and 49 are obvious over Dittli in view of Ziermann.

7
The prior art rejections to be reviewed in this appeal are incorrectly identified in
the PO App. Brief (at 4) and Reply Brief (at 3). The “Argument” section of the
Brief(s)? fails to address some grounds of rejection.
8
Patent Owner Appeal Brief (“PO App. Brief”) dated Feb. 25, 2011.
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(K) Claims 31-36 and 38-39 are obvious over Dittli in view of Loftus.
(L) Claim 37 is obvious over Dittli in view of Loftus and Rozman.
(M) Claim 37 is obvious over Dittli in view of Loftus and Milavec.
(N) Claim 46 is obvious over Dittli in view of Orr.
II. CLAIM CONSTRUCTION
As a step in our analysis, we determine the meaning of the claims.
Requester, Examiner and Patent Owner differ as to the meaning of several of the
claim terms. Because claim construction is critical to our analysis of the issues on
both appeal and cross appeal, we resolve these differences first. We are mindful
that we are to use the broadest reasonable construction of claim terms in light of
the specification. However, we do not import into claim terms limitations
described in the specification unless there is sufficient basis to do so. There is a
“heavy presumption” that a claim term carries its ordinary and customary meaning.
CCS Fitness, Inc. v. Brunswick Corp., 288 F.3d 1359, 1366 (Fed. Cir. 2002). By
“plain meaning” we refer to the ordinary and customary meaning the term would
have to a person of ordinary skill in the art.
A. “prevent substantial reverse power flow”
Construction of the phrase "prevent substantial reverse power flow" is in
dispute. At the heart of the dispute is whether the term requires that some reverse
power flow must be allowed (Patent Owner position) or whether the claim term
applies to circuits that indiscriminately prevent all reverse power flow (Requester
position). Patent Owner admits that the phrase “substantial reverse power flow” is
not explicitly defined in the specification. PO App. Brief, 11.
Patent Owner suggests that the phase "prevent substantial reverse power
flow" is defined by implication, pointing to embodiments of the invention that
allow some reverse power flow. Patent Owner draws a contrast between two types
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of reverse power flow – instantaneous reverse power flow and average reverse
power flow. Patent Owner would have us construe “substantial reverse power
flow” as used in claim 1 to mean substantial average reverse power flow. See PO
App. Br. 11-12. Patent Owner would also have us construe the claim term to
permit some reverse power flow and to exclude circuits that “indiscriminately
address[ing] all reverse power flow under certain conditions” such as e.g. Dittli.
See PO App. Br. 13. We understand Patent Owner’s preferred construction to be
that the term “prevent substantial reverse power flow” requires that some reverse
power must be allowed to flow, but not too much.
Requester argues for a more literal construction of the term. Requester
argues that the term “substantial” is a broadening term that modifies “reverse
power flow.” Cross App. Br. 10. According to Requester, the claim term allows
for but does not require some reverse power to flow. Id.
In the RAN, when discussing the Milavec reference, the Examiner expresses
agreement with Patent Owner’s position that a relatively small amount of negative
current power flow must be allowed, pointing to the '964 patent specification for
support. RAN 27. Nevertheless, the Examiner rejected numerous claims over
Dittli, which indiscriminately prevents all reverse power flow. RAN 21.
The '964 patent explains that reverse power flow can be damaging to
synchronous rectifier circuits. According to the specification, “it is desirable to
prevent substantial negative average inductor current, while a small amount of
negative instantaneous inductor current is considered acceptable.”
9
'964 patent
2:37-60.

9
See col. 10 lines 6-10. “To prevent large values of negative current Iave2, as this
may cause excessive power dissipation, a glitch on the bus voltage or other
performance problems (col. 9, lines 57- 61). Waveform 3 illustrates negative
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We do not adopt Patent Owner’s construction, which strains the plain
meaning of the words (even in context). Preventing X does not require Y. We
construe the phrase “prevent substantial reverse power flow” to mean that a
significant or effective portion of reverse power that might otherwise flow is
prevented from flowing. It is within the scope of the claim term that some reverse
power flow may be allowed so long as it is not substantial. The claim term permits
but does not require some reverse power flow as long as that reverse power flow is
not substantial. In other words, an insubstantial amount of reverse power is
acceptable and is permitted to flow. Preventing all reverse power flow prevents
substantial reverse power flow. Our construction does not encompass preventing
only an insignificant amount of reverse power flow. Nor does it require that there
must be some reverse power flow. Furthermore, our construction does not draw
the distinction between “instantaneous” and “average” power flow requested by
Patent Owner.
It would be a simple matter for the claim drafter to include words in the
claims that convey the Patent Owner’s proposed construction. For example, the
words “instantaneous” and “average” could have been included where appropriate
to draw that distinction. Likewise, it would have been possible to expressly define
the claim term in the specification so that its meaning in the claims would be
anchored to that definition.
The claim term, standing alone, does not require that a converter “operate[s]
in both synchronous and diode mode when functioning” as suggested by Patent

average inductor current Iave3 and negative instantaneous inductor current ILout3.
The specification notes that a relatively small amount of negative average current
flow Iave3 (e.g., -1 % to -5%) is not significantly detrimental to the operation of two
or more units in parallel but it is desirable to prevent substantial negative average
inductor current, for example Iave3.
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Owner, although such modes of operation may cause current flows that come
within our construction of the claim term. Our construction is in accord with both
the plain meaning of the claim terms and context in which the phase is used in the
specification.
The specification suggests that the problem being solved by the invention is
one of reverse power flow. It does not suggest that some amount of reverse power
flow is required.
10
Rather, some amount of reverse power flow (instantaneous or
average) is acceptable (tolerated). If the Patent Owner wanted the claim language
to require some reverse power flow or to describe average reverse power flow
(this seems to be important to Patent Owner), the claims could have been crafted to
say just that. However, Patent Owner elected not to make an express definition in
the specification and elected not to draw clear distinctions in the claims between
“instantaneous” and “average.”
We agree with Requester that it would place too narrow a construction on
the claim term to construe it as requiring some reverse power flow. Cross App. Br.
10.
B. “reference”
According to the Patent Owner, the claim term "reference" (see claims 1, 11
and 21) is not just any reference. Rather, it is a reference selected to develop a
particular control signal, specifically one that empowers the “synchronous rectifier
control circuitry” to disable the “synchronous rectifier device as a function of said
control signal to thereby prevent substantial reverse power flow through said
power converter.” PO App. Br. 10. Thus, Patent Owner’s construction of
“reference” is tied to its construction of “substantial reverse power flow.”

10
Requester notes numerous passages in the specification supporting our view.
See Cross App. Br. 11-16.
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The “reference” cited in Claim 1, 11 and 21 that is used for comparing with
"said characteristic" is a predetermined reference selected for the specific purpose
of preventing substantial reverse power flow, not merely any reverse power flow.
See RAN 27; PO App. Br. 9-10.
The Examiner construes “reference” as follows:
Thus, the “reference” of Claims 1, 11 and 21 is not just
any reference but defined as a reference for preventing
substantial reverse power flow. As noted in one
embodiment of the '964 Patent, the reference used for
comparison is at a predetermined level. (See column 7,
lines 61-63). Thus, the reference recited in Claims 1, 11
and 21 that is used for comparing with "said
characteristic" is a predetermined reference that is
selected for the specific function of preventing
substantial reverse power flow, not merely any reverse
power flow.

RAN 27. The Examiner cites to the only portion of the specification that
describes “reference” as follows:
The current signal is also provided to a level detector 375 which
compares the load current to some predetermined reference level.
When the converter is operating below some fraction of full rated
load current, perhaps 5% or 10%, the detector 375 will disable
the synchronous rectifier drive circuit 330. This action
reconfigures the converter from a synchronous rectifier circuit to
a conventional diode rectifier circuit. Since a diode rectifier
circuit cannot process power in the reverse direction, the
proposed circuit effectively prevents reverse power flow. When
the converter output current increases beyond the 5% or 10% trip
level (some hysteresis is probably preferred), the synchronous
rectifier drive circuit 330 is enabled, resuming normal operation.
Thus, the control circuit 350 transitions the switching circuitry
SR1, SR2 from the bidirectional mode to the unidirectional mode
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when the output current level drops below a predetermined
threshold level.

'964 patent, 7:61 to 8:10.
Requester’s position is that “[n]o more can be read into the term ‘reference’
than is apparent from the claims themselves; the reference is compared to some
characteristic of the power converter to determine whether to disable the
synchronous rectifier device.” Cross App. Br. 15.
We do not to read into the claim term the conditions imposed by certain of
the embodiments of the invention. Regardless of the manner in which particular
embodiments operate, Patent Owner chose to use the word “reference” without
significant qualification in claim 1 (and in other claims as well). If the Patent
Owner wanted the term “reference” to have specific qualifiers associated with it,
the claims could have been crafted to include those qualifiers. The context of the
word “reference” in a particular claim may explain how the reference relates to
other features of the claims and therefore provide a limitation. However, we do
not read such limitations into the word “reference” itself.
C. “soft start” (e.g. allowed claim 45)
The Examiner indicated that claim 45, which includes the term “soft start,”
is allowed. According to the Examiner, claim 45 is not anticipated by Dittli
because Dittli does not disclose synchronous rectifier control circuitry adapted to
"soft-start said at least one synchronous rectifier device when enabling thereof."
The Examiner indicates (RAN 37) that “soft start” should be limited to the
description in the ‘964 specification at 13:10-20, reproduced below.
The disruption can be avoided by soft starting the drive signal to
the switch Q2 thereby gradually increasing its duty cycle from
zero to its ultimate operating point. An analogous soft start may
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be employed for the current sensing embodiments, particularly, if
the load current threshold is set below the point at which the
diode rectifier circuit transitions to the discontinuous inductor
current mode. The timing circuits include, without limitation, an
enable/disable timing device and a soft start implementation
where the duty ratio is increased from a small value to its
ultimate operating point. (emphasis added)

Patent Owner agrees that the specification sufficiently indicates the scope of the
claim. PO Resp. Br. 5.
Requester urges a broader construction of the term “soft start” that is not
limited to a gradual increase of duty cycle. Rather, the term should be more
broadly interpreted to cover a gradual increase of the gate voltage of the
synchronous rectifier at start up. According to Requester, such a construction
would render claim 45 unpatentable based on Dittli. Cross App. Br. 16-17.
Although Requester urges a broader definition, no specific definition is proposed.
The term “soft start” is not defined explicitly in the specification. We could
not readily locate a dictionary definition of “soft start” that was contemporaneous
with the '964 patent and neither party, nor the Examiner, has provided such a
definition. U.S. Patent No. 6,760,235, roughly contemporaneous with the '964
patent, is directed to a power supply having a “soft start” feature. In that patent, a
duty cycle is increased gradually.
The parties have not put before us any persuasive evidence, other than the
'964 patent specification portion quoted above, that defines “soft start” as of the
date of invention.
Although we do not generally read specification limitations into claim terms,
we must define this claim term to analyze the issues at hand. The only helpful
explanation is from the specification itself. There is no evidence that “soft start”
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has a special meaning in the art and that we should contradict the meaning
attributed from the specification portion cited. Thus, in the absence of any
evidence other than the example given in the specification, we construe “soft start”
as requiring increasing duty ratio from a small value to its steady state operating
point.
III. EXAMINER-ADOPTED REJECTIONS
A. The Dittli Reference
Each of the Patent Owner appealed rejections depends on Dittli alone or in
combination with another reference. The Dittli Abstract describes the Dittli
invention as follows:
A synchronous rectifier having two MOSFETs and a transformer
with a primary winding and a first and second secondary winding
in the transformer and a control device in the rectifier circuitry.
The second secondary winding (tertiary winding) and the control
device are connected within the synchronous rectifier to provide
protection for the two MOSFETs from destruction caused by
reverse feed.

Dittli Fig. 2 is reproduced below.
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`

Dittli Figure 2
Dittli describes solving the problem of potential destruction of MOSFET’s 6,
7 as follows:
This circuit requires that a passive load be applied
between the outputs 14, 15. [I]f, however, two or more
rectifiers of the type that has just been described are
connected together in parallel, it is then possible-for
example, if the switching function of switch 4 were to
fail briefly-for current to flow back into the circuit, which
would lead to a short circuit through the MOSFETs 6, 7,
which are now conductive, and possibly to their
destruction. The two so-called substrate diodes of the
MOSFETs 6, 7 are shown as well by means of dashed
lines.

Dittli, 3:22-31.
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In the Fig. 2 embodiment, protection is provided by a circuit 17, connected
so as to sense a signal at one of the windings of the power transformer and control
a gate voltage of synchronous rectifiers 6 and 7. Dittli Figure 3 is reproduced
below.

Dittli Fig. 3
In the Fig. 3 embodiment, protection is provided in a different manner. A
control circuit 17 provides protection to MOSFET synchronous rectifiers 6 and 7.
A gate drive circuit 17, coupled to the gates of the synchronous rectifiers 6 and 7,
is located between the transformer secondary winding 16 and the gates of the
synchronous rectifiers 6 and 7. Circuit 17 disables the synchronous rectifiers to
prevent reverse power flow, thereby causing the power converter to be "impervious
to reverse feed." Dittli, Abstract and 1:32 to 2:11. Dittli states that the power
converter may be configured in parallel with one or more other converters. Dittli,
1:21-29; 3:21-31.
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B. Patent Owner Denominated Rejections “A”
1. Independent claim 1
Claim 1 is illustrative and is reproduced below with disputed terms
emphasized and letter designations added to the limitations.
1. For use with a power converter including a synchronous
rectifier circuit having switching circuitry with at least one
synchronous rectifier device and adapted to rectify substantially
alternating current to produce substantially direct current, a
control circuit, comprising:
(a) a sensor capable of sensing a characteristic of said
power converter;
(b) comparison circuitry capable of comparing said
characteristic with a reference and developing a control signal
in accordance therewith; and
(c) synchronous rectifier control circuitry, coupled to said
comparison circuitry, adapted to disable said at least one
synchronous rectifier device as a function of said control signal
to thereby prevent substantial reverse power flow through said
power converter.

2. comparison circuitry
a. “reference”
The Examiner adopted this Requester-proposed rejection for the reasons set
forth in the request for reexamination at pages 54-58, and matched items at pages
1-19 of Appendix A.6 of the Request and at pages 21-26 of Requester’s response
filed May 27, 2010, all of which were incorporated by reference into the RAN
page 21. Dittli transistors 36 and 37 are regarded as the “comparison circuitry”
and the gate-source threshold of these transistors are regarded as the claimed
“reference.” See Request at 54-58.
Patent Owner argues that Dittli doesn’t teach the “reference” required by
claim 1. According to Patent Owner, the gate source threshold of transistors 36
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and 37 does not constitute a “reference” as required by claim 1. Rather, according
to Patent Owner, the “reference” recited in claim 1 must be a predetermined
reference established at a level so as to prevent substantial reverse power flow.
App. Brief, 9-10. Further, according to Patent Owner, the “reference” is a
“particular” reference used to develop a particular control signal. That particular
control signal empowers the “synchronous rectifier control circuitry” of claim 1 to
disable the synchronous rectifier device as a function of the control signal to
prevent substantial reverse power flow through the power converter. Patent Owner
refers to the specification to support this description of “reference.” In particular,
Patent Owner points to level detector 375 in Fig. 3 of the '964 patent. The
reference used for comparing is a “predetermined reference level.” '964 patent
7:61-63). Patent Owner argues that the language of claim 1 and the specification
“mandate” that the “reference” of claim 1 be a predetermined level selected to
cause a particular function.
Dittli doesn’t meet Patent Owner’s construction of “reference” in that the
functions attached to Patent Owner’s construction do not occur. PO App. Br. 10.
Accordingly Dittli is “impervious to reverse feed” and indiscriminately stops all
reverse power flow. PO App. Brief, 10 citing to Dittli, 7:61-63. According to
Patent Owner, the claim term “substantial reverse power flow” is defined by
implication. PO App. Br. 11. Patent Owner distinguishes between two types of
reverse power flow: 1) instantaneous reverse power flow, and 2) average power
flow. PO App. Br. 12. According to Patent Owner, the Dittli circuit is not as
“intelligent” as the claimed circuit in that the claimed “reference” is selected
particularly to distinguish between “insubstantial” and “substantial” reverse power
flow.
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Therefore, as indicated, Patent Owner argues that Dittli does not teach the
“reference” required by claim 1. In particular, the reference of claim 1 is a
particular reference used to develop a particular control signal that empowers the
“synchronous rectifier control circuitry” of claim 1 to disable the “synchronous
rectifier device as a function of said control signal to thereby prevent substantial
reverse power flow through said power converter.” PO App. Brief 10 citing to
claim 1. Patent Owner also points to the specification and to level detector 375
(Fig. 3) in construing “reference.”
We do not read into the claim term “reference” the requirements as
described in the specification. Transistors 6 and 7 themselves operate so as to
compare their respective gate voltages to their respective threshold voltages, acting
as a reference. It does not matter that the reference is a characteristic of the
transistor itself. The effect is to compare the gate voltage to the reference and
cause the transistor to turn “on” if the gate voltage is sufficient to overcome the
threshold. Thus, as proffered by the Requester and adopted by the Examiner,
Dittli detects whether the primary side transistor is turning on at a regular interval.
This fact is a “characteristic” of the power converter. A signal indicative of this
characteristic is manifested in the voltage across capacitor 33. When this voltage
does not meet the threshold voltage of the switches 36, 37, they are turned off,
which in turn disables the synchronous rectifiers 6, 7 and thereby prevents reverse
power flow through the power converter.
The Examiner finds that the gate-source threshold of transistors 36 and 37
constitutes a “reference” as used in claim 1. We agree. The claims don’t require
that the reference and comparison be “intelligent”…only that it “prevent
substantial reverse power flow” which it does. According to our construction,
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preventing “substantial reverse power flow” includes preventing all reverse power
flow.
Our construction of “reference” encompasses the gate-source threshold of
the Ditli transistors. Dittli does not state explicitly that the gate-source threshold
acts as a “reference.” Nevertheless, it does. A voltage applied to the gate is
effectively compared with the gate-source threshold. If the gate voltage is
sufficient, the threshold is overcome and the semiconductor junction permits
current to flow.
b. substantial reverse power flow
Patent Owner then argues that Dittli “indiscriminately” addresses all power
flow rather than the claimed “substantial reverse power flow.” This indiscriminate
stopping of all reverse power flow occurs only when power switch 4 malfunctions
or the secondary winding 16 of transformer 3 is not provided pulses via power
switch 4. See PO App. Brief, 10. We are not persuaded that the terms of claim 1
are not met by Dittli. While the stopping of all reverse power flow may occur
indiscriminately when power switch 4 malfunctions or otherwise fails to deliver
pulses, the claim terms are nonetheless met. Transistors 6 and 7 operate as
comparison circuits, the outputs of which control respective synchronous diodes to
prevent substantial reverse power flow.
Patent Owner notes that the specification does not explicitly define
“substantial reverse power flow.” PO App. Br. 11. We agree. However, Patent
Owner argues that “substantial reverse power flow” is defined by implication, i.e.
according to its usage. PO. App. Br. 11.
Patent Owner refers to the '964 patent, 9:34 to 10:10 and Figure 6. These
portions of the specification explain the difference between “instantaneous” and
“average” reverse power flow, the “average” reverse power flow describing a
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situation in which a net negative inductor current exists over more than one
switching cycle. PO App. Br. 11-12. Patent Owner focuses on specification
description that it is beneficial to prevent substantial reverse power flow while
permitting other reverse power flow during operation. PO App. Br. 12. Patent
Owner notes that Dittli fails to provide such “intelligent” design that can
distinguish between these two different situations.
Patent Owner is correct. Dittli does not distinguish between these two
situations. But that does not resolve the dilemma of whether to read into
“substantial reverse power flow” the requirement that it refer only to “average”
power flow, rather than to instantaneous power flow.
Patent Owner draws a contrast between Dittli and claim 1 in that “the
converter of Claim 1 operates in both synchronous and diode mode when
functioning.” PO App. Brief, 10. Patent Owner’s argument distinguishing
“average” and “instantaneous” has clearer significance in the context of a converter
that operates in both synchronous and diode mode. However, Patent Owner reads
too much into claim 1. Claim 1 is not directed to a converter that operates in any
particular mode. It is simply directed to “a control circuit” for use with a power
converter that includes a synchronous rectifier device that rectifies AC to DC.
There is no basis in the claim 1 language to assume any kind of operational modes.
There is no context in the claim itself that would suggest that we read in particular
functional language to the claim term “substantial reverse power flow.”
Column 9, line 47, to column 10, line 10, and Figure 6 of the '964 Patent
discuss what might imply a "substantial reverse power flow" as recited in
independent Claim 1. Patent Owner points to three portions of the '964 Patent as
impliedly defining “substantial reverse power flow. See, for example, '964 patent,
9:34-43; 9:61-67 and 10:3-10.
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The quoted portions discuss substantial reverse power flow, but do not
define it explicitly. The Patent Owner’s references to Fig. 6 of the '964 patent are
not helpful in establishing a definition of “substantial reverse power flow” even
though they help to explain its significance. The specification author had the
opportunity to craft an explicit definition if that was desired. Furthermore, the
claim crafter could have written into the as many of the qualifiers in these portions
of the specification as desired.
In accordance with out construction of the claim term “reference,” Dittli
teaches a “reference” and it teaches a control circuit that prevents substantial power
flow through the power converter as claimed.
3. claim 1, limitation (c)
Patent Owner argues that Ditli does not teach “synchronous rectifier control
circuitry, coupled to said comparison circuitry, adapted to disable said at least one
synchronous rectifier device as a function of said control signal to thereby prevent
substantial reverse power flow through said power converter.” PO App. Br. 14-16;
claim 1, limitation (c).
Patent Owner argues that the Examiner’s reliance on transistors 36 and 37 of
Dittli to disclose the “synchronous rectifier control circuitry” of claim 1 is
inappropriate. PO App. Br. 14. This is because transistors 36 and 37 do not
disable MOSFET 6 and 7 of Dittli. Rather, according to Patent Owner these
MOSFETs are turned off when power switch 4 malfunctions or secondary winding
16 of transformer 3 does not provide pulses via power switch 4. Dittli does not
operate in both “synchronous” and “diode” modes. PO App. Br. 14.
Our review of Dittli does not support Patent Owner’s position and comports
with Requester’s description of the Dittli circuit. See Req. Resp. Br. 7-8. Dittli
shows in Figs. 3 and 4 synchronous rectifiers 6 and 7 that are enabled by respective
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transistors 36 and 37 when the voltage applied to their gates exceeds to voltage on
lines 26 and 27 by the threshold of the transistors. Thus, transistors 36 and 37
function as control circuitry in that the signal developed by them enables and
disables synchronous rectifiers 6 and 7.
Patent Owner argues that Dittli does not operate in both synchronous and
diode modes. PO App. Br. 14. Requester argues that this is not the case and offers
explanation set forth in Requester’s Respondent Brief at pages 7-8. Whether the
Dittli circuit operates in both a synchronous and a diode mode is irrelevant to claim
1. Claim 1 does not require the claimed “control circuit” to operate in both
synchronous and diode modes. Claim 1 is simply directed to a control circuit that
disables a synchronous rectifier under certain conditions.
For these reasons we are not persuaded that limitation (c) is not met by
Dittli.
4. unreasonably broad interpretation
Patent Owner argues that the anticipation rejection of claim 1 is improper
because the Examiner has adopted an unreasonably broad interpretation of the
claim language. PO App. Br. 14-16.
In accordance with our claim constructions, the claimed “reference”
encompasses the internal threshold of Dittli transistors 36 and 37, which must be
overcome by the voltage on capacitor 33 appearing at lines 26 and 27. Transistors
36 and 37 disable synchronous rectifiers 6 and 7 respectively. The limitations of
claim 1 are met. We decline to import limitations from the specification,
particularly when the claim drafter could have included language in the claims to
more clearly define them.
For the above reasons, we sustain the Examiner’s rejection of claim 1.
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5. Claims 2, 4-5, 8-9 and 43-44
Patent Owner did not separately argue dependent claims 2, 4-5, 8-9 and 43-
44, relying on the arguments made with respect to claim 1. PO App. Br. 16. In
accordance with our conclusions with respect to claim 1, we also sustain the
Examiner’s rejection of these dependent claims.
C. Patent Owner Denominated Rejections “B”
1. Independent claim 11
Independent method claim 11 is reproduced below with emphasis and added
limitation labels.
11. For use with a power converter including a synchronous
rectifier circuit having switching circuitry with at least one
synchronous rectifier device and adapted to rectify substantially
alternating current to produce substantially direct current, a method
for controlling said synchronous rectifier circuit, comprising:
(a) sensing a characteristic of said power converter;
(b) comparing said characteristic with a reference and
developing a control signal in accordance therewith; and
(c) disabling said at least one synchronous rectifier device
as a function of said control signal to thereby prevent substantial
reverse power flow through said power converter.

2. comparing…developing a control signal
a. reference
Patent Owner argues that “comparing said characteristic with a reference
and developing a control signal in accordance therewith” is not taught by Dittli.
PO App. Br. 16.
Patent Owner makes the same argument regarding “reference” as made with
respect to claim 1, namely that the claimed “reference” is a predetermined level
selected to cause a particular function to occur. PO App. Br. 17. For the same
reasons set forth above with respect to claim 1, we are not persuaded.
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b. reverse power flow
Patent Owner also argues “substantial reverse power flow” by incorporating
the argument made with respect to claim 1. PO App. Br. 18. For the same reasons
enunciated with respect to claim 1, we are not persuaded.
3. limitation (c)
Patent Owner argues that limitation (c) is not taught by Dittli. PO App. Br.
18. The argument presented is essentially the same as presented with respect to
claim 1. According to Petitioner, transistors 36 and 37 do not disable MOSFETs 6
and 7. MOSFETs 6 and 7 are turned-off when the power switch 4 malfunctions or
the secondary winding 16 is not provided pulses via power switch 4. For this this
reason, the Dittli circuit, it is argued, does not operate in both synchronous and
diode modes. PO App. Br. 18. We disagree for the same reasons as explained
above with respect to claim 1.
4. unreasonably broad interpretation
For the same reasons as set forth above with respect to claim 1, we are not
persuaded by Patent Owner’s argument that the Examiner has unreasonably
broadly interpreted the claim language.
For these reasons we sustain the Examiner’s rejection of independent claim
11.
5. dependent claims 12, 14-15 and 18-19
Claims 12, 14-15 and 18-19 depend directly or indirectly from and further
limit claim 11. Patent Owner does not separately argue dependent claims 12, 14-
15 and 18-19. For the reasons expressed with respect to claim 11, we likewise
sustain the Examiner’s rejection of these dependent claims.
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D. Patent Owner Denominated Rejections “C,” claims 21-24, 27-28 and 30
1. Independent claim 21
Independent method claim 21 is reproduced below with emphasis and added
limitation labels.
21. A power converter having an input and an output,
comprising:
(a) at least one power switch coupled to said input;
(b) a power transformer having primary and secondary
windings, said primary winding coupled to said at least one power
switch;
(c) a synchronous rectifier circuit, interposed between said
secondary winding and said output, including switching circuitry
with at least one synchronous rectifier device and adapted to rectify
substantially alternating current to produce substantially direct
current; and
(d) a control circuit, coupled to said synchronous rectifier
circuit, including:
(e) a sensor capable of sensing a characteristic of said power
converter,
(f) comparison circuitry capable of comparing said
characteristic with a reference and developing a control signal in
accordance therewith, and
(g) synchronous rectifier control circuitry, coupled to said
comparison circuitry, adapted to disable said at least one
synchronous rectifier device as a function of said control signal to
thereby prevent substantial reverse power flow through said power
converter.

2. comparing…developing a control signal
a. reference
Patent Owner makes essentially the same argument (PO App. Br. 21) made
with respect to claim 1. For the same reasons as set forth above with respect to
claim 1, we reject that argument.
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b. substantial reverse power flow
Patent Owner makes the same argument regarding “substantial reverse
power flow” as made with respect to claim 1. PO App. Br. 21. For the same
reasons stated above with respect to claim 1, we reject that argument.
3. Independent claim 21 limitation (g)
Patent Owner makes the same argument as made with respect to claim
1 that transistors 36 and 37 are not adapted to disable MOSFETs 6 and 7. In
addition, Patent Owner argues that Dittli does not operate in both synchronous and
diode modes when functioning to prevent substantial reverse power flow. PO App.
Br. 22. For the same reasons explained with respect to claim 1, we are not
persuaded.
4. claim 21 unreasonably broad interpretation
Patent Owner’s argument regarding “unreasonably broad interpretation of
claim language” made with respect to claim 21 is substantially the same as the
corresponding argument made with respect to claim 1. PO App. Br. 22. For the
same reasons, we are not persuaded by Patent Owner’s argument as it applies to
claim 21.
5. Dependent claims 22-24, 27-28 and 30
Claims 22-24, 27-28 and 30 depend directly or indirectly from and further
limit claim 21. They are not separately argued. As such, given our analysis with
respect to claim 21, we sustain this ground of rejection.
E. Patent Owner Denominated Rejections “D,” claims 3 and 13
Claims 3 and 13 depend from claims 1 and 11 respectively. They each
further require a “clamping circuit.” Patent Owner does not separately argue this
claim feature. PO App. Br. 24. Given our analysis of Dittli with respect to claim
1, we sustain this rejection for the same reasons as set forth above.
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F. Patent Owner Denominated Rejections “E,” claims 6, 16 and 25
Claims 6, 16 and 25 depend from claims 1, 11 and 21 respectively. They
each further require “active load sharing.” Patent Owner does not separately argue
this claim feature. PO App. Br. 24. Given our analysis of Dittli with respect to
claim 1, we sustain this rejection for the same reasons as set forth above.
G. Patent Owner Denominated Rejections “F,” claims 7, 17 and 26
Claims 7 depends from and further limits claim 1. Claim 17 depends from
and further limits claim 11. Claim 26 depends from and further limits claim 21.
Claims 7, 17 and 26 each require that the switching circuitry comprise at least one
discrete diode. Patent Owner does not argue separately the specific features of
these claims. PO App. Br. 24. Given our analysis of Dittli with respect to claim 1,
we sustain this rejection for the same reasons as set forth above.
H. Patent Owner Denominated Rejections “G,” claims 7, 17, 26, 42
Claims 7 and 42 depend from and further limits claim 1. Claim 17 depends
from and further limits claim 11. Claim 26 depends from and further limits claim
21. Claims 7, 17 and 26 each require that the switching circuitry comprise at least
one discrete diode. Claim 42 requires that the “characteristic” represent toggling
of a logic state associated with the power converter. Patent Owner does not argue
separately the specific features of these claims. PO App. Br. 25. Given our
analysis of Dittli with respect to claim 1, we sustain this rejection for the same
reasons as set forth above.
I. Patent Owner Denominated Rejections “H,” claims 41 and 42
Claims 41 and 42 each depend from claim 1. Claim 41 requires that the
“characteristic” is an error signal of the power converter. Claim 42 requires that
the “characteristic” represent toggling of a logic state associated with the power
converter. Patent Owner does not argue separately either of these additional claim
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limitations. PO App. Br. 25. Given our analysis of Dittli with respect to claim 1,
we sustain this rejection for the same reasons as set forth above.
J. Patent Owner Denominated Rejections “I,” claims 42, 47, 48, 49
Claims 42, 47, 48 and 49 depend from and further limit claim 1. Patent
Owner does not argue separately these claims other than to note that Yamamura
does not cure the deficiencies of Dittli. PO App. Br. 25. Based on our analysis of
claim 1 with respect to Dittli, we sustain this ground of rejection.
K. Patent Owner Denominated Rejections “J,” claims 47 and 49
Claims 47 and 49 each depend from claim 1. Claim 47 further requires
disabling a rectifier for a period of time during start up. Claim 49 requires that the
control circuitry is a “control driven circuit.” Ziermann is additionally cited in
combination with Dittli to meet the specific limitations of claims 47 and 49. Patent
Owner does not contest that Ziermann teaches those specific limitations. PO App.
Br. 26. In view of our conclusions with respect to claim 1, we sustain this
rejection for the same reasons as set forth above.
L. Patent Owner Denominated Rejections “K,” claims 31-36 and 38-39
1. “a control circuit…converters” (claim 31)
The Examiner relies on Dittli control circuit 17 as meeting the “control
circuit” limitation of claim 31. Patent Owner argues that Dittli “indiscriminately”
addresses all reverse power flow and does this only when the power switch 4
malfunctions or the secondary winding 16 of transformer 3 is not provided pulses
via power switch 4. Patent Owner contrasts this with claim 31 which Patent
Owner characterizes as operating in both synchronous and diode mode when
functioning. PO App. Br. 27. Despite Patent Owner’s characterization, we do not
read independent claim 31 as requiring both synchronous and diode mode
operation.
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Loftus teaches load sharing. See Loftus at Title. However, claim 31
requires first and second power converters and a control circuit that prevents one of
those power converters from creating reverse power flow in the other. Requester
does not explain sufficiently a teaching to this effect supported by either Dittli or
Loftus. We therefore do not sustain the rejection of claim 31 based on Dittli and
Loftus.
2. claims 32-36 and 38-39
For the reasons set forth above with respect to claim 31, we likewise do not
sustain the rejection of dependent claims 32-36 and 38-39.
M. Patent Owner Denominated Rejections “L,” claim 37
Claim 37 depends from claim 31. Patent Owner’s argument with respect to
Rozman relies on the inadequacy of Dittli and Loftus. PO App. Br. 28. Given our
analysis of Dittli and Loftus with respect to claim 31, we do not sustain this
rejection for the same reasons as set forth above.
N. Patent Owner Denominated Rejections “M,” claim 37
Claim 37 depends from claim 31. Patent Owner’s argument with respect to
Milavec relies on the inadequacy of Dittli and Loftus. PO App. Br. 29. Given our
analysis of Dittli and Loftus with respect to claim 31, we do not sustain this
rejection for the same reasons as set forth above.
O. Patent Owner Denominated Rejections “N,” claim 46
Claim 46 is an independent claim that is similar to claim 1 but also requires
that the “power converter is a non-isolated buck converter.” Patent Owner does
not dispute that Orr teaches a “buck converter.” This rejection is not separately
argued, but argued only as to not curing the deficiencies of Dittli. PO App. Br. 29.
Given our analysis of Dittli with respect to claim 1, we sustain this rejection for the
same reasons as set forth above.
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P. Summary
We sustain the Examiner’s rejection of claims 1-9, 11-19, 21-28 and 30.
We do not sustain the Examiner’s rejection of claims 31-39.
IV. CROSS-APPEAL NON-ADOPTED REJECTIONS
A. Examiner’s decisions
For convenience, we adopt the Requester’s denominations of non-adopted
rejections as set forth in the Requester’s Cross Appeal Brief as follows:
B1-B7 (based on Milavec alone and in combination)
C1-C7 (based on Orr alone and in combination)
D1-D10 (based on Ziermann alone and in combination)
E1-E9 (Yamamura alone and in combination)
F1 (claim 45 based on Dittli)
[G1]
11
(35 U.S.C. §112, first paragraph)
B. Requester Denominated non-adopted rejections “B1-B7” (anticipation
by Milavec and obviousness based on Milavec and various other references)
Milavec describes a synchronous rectifier that is impervious to reverse feed.
Milavec, Title. The Examiner’s stated reasons for not adopting proposed rejections
based on Milavec are based on the Examiner’s finding that a system that prevents
“any” reverse power flow does not anticipate a system that has a “reference” and
that “prevents substantial reverse power flow.” RAN 26-28.
Requester argues that the Examiner’s failure to maintain rejections B
through E of each of independent claims 1, 11, 21, 31 and 46 was based solely on
an improperly narrow interpretation of the phrase “prevent substantial reverse
power flow through said power converter;” and a narrow interpretation of

11
There is no Requester denomination in Req. Cross App. Br.
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“reference.” Cross App. Br. 19-20. We agree with the Requester that the
Examiner’s stated rationale is not correct. Our constructions of the claim terms
“reference” and “prevents substantial reverse power flow,” which are not as
narrow as those adopted by the Examiner, lead us to the conclusion that the
Examiner should not have dismissed Milavec.
Requester interprets the operation of the Milavec circuit by reference to
Milavec Figs. 4 and 6. Cross App. Br. 20. Requester states the following: “Thus,
although Milavec does not explicitly say at what current threshold the synchronous
rectifiers are disabled, the circuitry allows for a negative instantaneous or average
current and one skilled in the art would allow for that negative current.” Cross
App. Br. 20. Patent Owner disagrees with Requester’s assessment of the Milavec
disclosure. PO Resp. Br. 11.
However, we agree with Requester’s analysis, particularly in view of our
claim constructions set forth above. We therefore do not sustain the Examiner’s
decision not to adopt proposed rejections “B2-B7”.
C. Requester Denominated Rejections (non-adopted) “C1-C7”
(anticipation by Orr and obvious based on combinations with Orr).
Requester argues that but for claims 42 and 46, the Examiner’s only basis
for distinguishing the Orr reference (alone or in combination) was that a system
that prevents “any” reverse power flow does not anticipate a system that has a
“reference” and that “prevents substantial reverse power flow.” Cross App. Br. 21.
Requester correctly notes that claim 31 does not require a “reference.”
However, the RAN states more than that. According to the Examiner, Orr’s
Vref is not used to develop a control signal to prevent substantial reverse power
flow through the converter. Rather, it is selected to insure that an overvoltage
condition shuts down the converter. RAN 29. Furthermore, the Examiner notes
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that in Orr, toggling denotes switching between two options wherein toggling of a
logic state would be switching between two different logic states. Orr’s output of
A5 (Orr Fig. 8) does not represent toggling of a logic state as required by claim 42.
Rather, it is a comparison signal generated by a voltage comparison. See Orr at
228.
In the absence of further evidence from Requester that Orr meets all of the
limitations of the claims at issue, we sustain the Examiner’s decision as to claims
1-6, 8, 9, 11-16, 18, 19-25, 27, 28, 31-36, 38, 39 and 41-42 (claim 42 depends from
claim 1).
As to claim 46, the Examiner did not adopt Requester’s proposed rejection
based on Orr and Yamamura. According to the Requester, Orr discloses all
limitations of claim 46 except that the buck converter is non-isolated. Based on the
requirements of KSR, Yamamura cures that deficiency. Cross App. Br. 22.
The Examiner points out that Orr discloses a “buck converter” (defined by
the '964 patent as a “non-isolated buck converter” at 9:4-5. According to the
Examiner, Yamamura discloses a “non-isolated boost converter.” Requester has
not provided persuasive evidence that it would not have been obvious to include
the Orr “buck converter” in the Yamamura “non-isolated boost converter. R 30-
31. In the absence of persuasive evidence from Requester, we sustain the
Examiner’s decision not to adopt the proposed rejection of claim 46.
D. Requester Denominated Rejections (non-adopted) “D1-D10”
Requester argues that but for claim 47, the only basis for distinguishing
Ziermann presented by the Patent Owner or Examiner was that a system that
prevents “any” reverse power flow does not anticipate a system that has a
“reference” and that “prevents substantial reverse power flow.” Requester further
argues that Ziermann does allow some negative current flow. The Examiner’s
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decision not to adopt rejections based on Ziermann was founded on the Examiner’s
construction of “reference” and “substantial reverse power flow.” No other
rationales were presented either by the Examiner or by Patent Owner.
We have reviewed Ziermann. It describes an “enhanced synchronous
rectifier.” Ziermann at Title. According to its Abstract, “[t]he synchronous
rectifier also includes a circuit for sensing a condition indicative of the onset of the
discontinuous interval and turning off the power switching device for at least the
duration of the discontinuous interval, independent of the time duration of the
discontinuous interval.” Given our construction of “reference” and “substantial
reverse power flow,” the Examiner has not provided sufficient reasoning for
declining this ground of rejection. If there are good and sufficient reasons for not
going forward with this set of rejections, they are not sufficiently articulated.
Therefore, based on this record, we do not sustain the Examiner’s decision not to
adopt these rejections.
E. Requester Denominated Rejections (non-adopted) “E1-E9”
Requester argues that but for claims 42 and 47, the only basis for
distinguishing Yamamura presented by the Patent Owner or Examiner was that a
system that prevents “any” reverse power flow does not anticipate a system that
has a “reference” and that “prevents substantial reverse power flow.” We agree.
See RAN 35. Furthermore, the Examiner points to the Yamamura step up circuit
70 that is configured to prevent any counter current flow. RAN 35.
No further analysis is presented by either by the Examiner or by Patent
Owner. Given our construction of “reference” and “substantial reverse power
flow,” the Examiner has not provided sufficient reasoning for declining this ground
of rejection. If there are good and sufficient reasons for not going forward with
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this set of rejections, they are not sufficiently articulated. Therefore, based on this
record, we do not sustain the Examiner’s decision not to adopt these rejections.
F. Requester Denominated Rejections “F1” (claim 45)
Requester argues that the only difference between Dittli and claim 45 noted
by the Examiner is the “soft start” requirement of claim 45. Cross App. Br. 28.
However, based on our construction of “soft start” requiring a gradual increase in
duty cycle, Dittli does not anticipate claim 45. We therefore sustain the
Examiner’s decision not to reject claim 45 based on Dittli.
G . Rejection “G1” (35 U.S.C. § 112, first paragraph)
Each of new claims 42-44 recites a specific “characteristic.” Antecedent
basis for “characteristic” is found in claim 1 which recites “a sensor capable of
sensing a characteristic of said power converter.” Control circuits of the '964
patent are shown in Figs. 3 and 5. Requestor quotes from the '964 patent
description of Fig. 5:
Consequent1y, the "input" to the control circuit 520 [sic
530] illustrated in FIG. 5 employed to trigger a timer
could be a variety of signals including, without
limitation, toggling of a logic state, initiation of the drive
pulse train or input voltage level.

'964 patent 11:57-61. Requestor notes the label of box 530 reads “Sensor or
Timer” and draws the conclusion that they are alternatives. Claim 1, from which
claims 42-44 depend, refers to a “sensor.” However, according to the Requester,
claims 42-44 refer to characteristics (toggling of logic state, drive pulse train, input
voltage level) that are described in the quoted passage above as inputs to a “timer.”
There is no description in the '964 patent specification related to comparing such
characteristics with a “reference” as required by claims 42-44. Cross App. Br. 29.
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Patent Owner argues that claims 42-44 (and claims 47-48) are at least
inherently supported by the original specification. Patent Owner’s arguments are
more fully developed in the Patent Owner’s response to the ACP. PO Resp.
Br. 14.
We do not read “reference” as being restricted to some analog value. The
“reference” could be, for example, a reference logic state input to a comparator,
thus allowing the toggling of a logic state to generate a control signal that is used
to control a rectifier. Furthermore, we do not regard the word “sensor” as used in
claim 1 to be inconsistent with determining a comparison of the characteristics
described in claims 42-44 with their appropriate respective references. The
appropriate circuits would have been well within the level of an ordinarily skilled
power circuit designer at the time of the '964 patent invention.
For these reasons, we sustain the Examiner’s action in not rejecting claims
42-44 based on 35 U.S.C. § 112, first paragraph.
Requester argues that the Examiner should have adopted the proposed
rejection of claim 47 based on 35 U.S.C. § 112, first paragraph because there is no
support in the specification for the limitations set forth in claim 47 requiring
further adaptation of the claim 1 circuit to disable a synchronous rectifier for a
period of time based on a voltage at the converter output. Cross App. Br. 29. The
Examiner noted that based on the Patent Owner’s explanations of support, that he
would not maintain the 35 U.S.C. § 112, first paragraph rejections of claims 42-44,
47-48 and others. RAN 3.
The '964 patent specification describes various start up conditions and
appropriate responses in columns 10-12. We agree with the Examiner that there is
sufficient explanation to support the claim 47 limitations.
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New claim 48, depending from claim 47 (and indirectly from claim 1)
describes that the sensor is a “timing circuit.” Requester makes the same argument
as above regarding “alternative” circuits in Fig. 5. For the same reasons as above
discussed with respect to claims 42-44, we sustain the Examiner’s decision not to
reject claim 48 under 35 U.S.C. § 112, first paragraph.
H. Summary
As to the Requester’s cross appeal, we sustain the Examiner’s decisions not
to adopt Requester denominated rejections “C1-C7”, “F1” and “G1”.
We do not sustain the Examiner’s decisions not to adopt rejections “B1-B7”,
“D1-D10” and “E1-E9”.
V. ORDER
It is
ORDERED that the rejection of claims 1-9, 11-19, 21-28, 30, 41-44 and 46-
49 is AFFIRMED;
FURTHER ORDERED that the rejection of claims 31-39 is REVERSED.
FURTHER ORDERED that the Examiner decision not to adopt Cross
Appeal Brief denominated rejections “B1-B7”, “D1-D10” and “E1-E9” is
REVERSED. These rejections are to be treated as new grounds of rejection.
Extensions of time for taking any subsequent action in connection with this
appeal are governed by 37 C.F.R. § 1.956. See 37 C.F.R. § 41.79.
Requests for rehearing in this inter partes reexamination proceeding are
governed by 37 C.F.R. § 41.79.
This decision also contains new grounds of rejection pursuant to 37 C.F.R. §
41.77(b) which provides “[a]ny decision which includes a new ground of rejection
pursuant to this paragraph shall not be considered final for judicial review.” 37
C.F.R. § 41.77(b) also provides that the Patent Owner, WITHIN ONE MONTH
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FROM THE DATE OF THE DECISION, must exercise one of the following two
options with respect to the new grounds of rejection to avoid termination of the
appeal as to the rejected claims:
(1) Reopen prosecution. The owner may file a response requesting
reopening of prosecution before the examiner . . . .
(2) Request rehearing. The owner may request that the proceeding be
reheard under § 41.79 by the Board upon the same record . . . .
Should the Patent Owner elect to prosecute further before the Examiner
pursuant to 37 C.F.R. § 41.77(b)(1), in order to preserve the right to seek review
under 35 U.S.C. § 141 with respect to the affirmed rejections, the effective date of
the affirmance is deferred until conclusion of the prosecution before the Examiner
unless, as a mere incident to the limited prosecution, the affirmed rejections are
overcome.
If the Patent Owner elects prosecution before the Examiner and this does not
result in patentable claims, abandonment or a second appeal, this case should be
returned to the Board of Patent Appeals and Interferences for final action on the
affirmed rejections, including any timely request for rehearing thereof.

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Patent Owner:

GLENN W. BOISBRUN
HITT CHWANG & GAINES, P.C.
P.O. BOX 832570
RICHARDSON, TX 75083

Third Party Requester:

JAMES M. SMITH, ESQ.
HAMILTON, BROOK SMITH & REYNOLDS, P.C.
530 VIRGINIA ROAD
P.O. BOX 9133
CONCORD , MA 01742-9133