SynQor Inc. v. Cisco Systems, Inc.
MEMORANDUM AND OPINION ORDER re Construction Briefs. Signed by Magistrate Judge Caroline Craven on 7/11/2014. (sm, )
IN THE UNITED STATES DISTRICT COURT
FOR THE EASTERN DISTRICT OF TEXAS
CISCO SYSTEMS, INC.,
MEMORANDUM OPINION AND ORDER
The above-referenced case was referred to the undersigned United States Magistrate
Judge for pre-trial purposes in accordance with 28 U.S.C. § 636. Before the Court are Plaintiff’s
Supplemental Claim Construction Brief (Docket Entry #72), Defendants’ Response (Docket
Entry #79), Plaintiff’s Reply (Docket Entry #81), and Defendants’ Surreply (Docket Entry #82).
Plaintiff filed suit on January 28, 2011, alleging infringement of six patents-in-suit: U.S.
Patent Nos. 7,072,190 (“‘190 Patent”), 7,269,034 (“‘034 Patent”), 7,272,021 (“‘021 Patent”),
7,558,083 (“‘083 Patent”), 7,564,702 (“‘702 Patent”) and 8,023,290 (“‘290 Patent”). All of the
patents contain disputed claim terms except for the ‘034 Patent for which there are no disputed
The patents are all related.
All of the patents except for the ‘021 Patent have a
continuation and divisional chain to a common parent application. These continuation/divisional
patents have similar, though not identical, specifications and reference is generally made herein
to the ‘190 Patent. The ‘021 Patent is a continuation-in-part patent having a differing
specification that claims priority at least in part through a variety of applications to the common
The ‘190 Patent, ‘034 Patent, ‘021 Patent, ‘083 Patent, and ‘702 Patent were the subject
of a prior suit brought by SynQor against a different set of defendants, SynQor, Inc. v. Artesyn
Techs., Inc., et al., Case No. 2:07-cv-497-TJW-CE (“‘497 case”). In the ‘497 case, a claim
construction order was issued on July 26, 2010. ‘497 case, Docket Entry # 474 (“‘497 Order”).
The Federal Circuit affirmed the trial court findings that the patents were valid and infringed.
SynQor, Inc. v. Artesyn Techs., Inc., et al., 709 F.3d 1365 (Fed. Cir. 2013). A number of
reexamination proceedings have taken place for the patents-in-suit subsequent to the ‘497 Order.
On January 2, 2014, this Court construed a number of terms in the patents-in-suit. See
generally Docket Entry #4; see also Docket Entry #67. Cisco asserts that SynQor had previously
asserted ‘190 Patent Claim 28 only against products incorporating unregulated or semi-regulated
bus converters. (Docket Entry #72 at 3). Accordingly, Cisco did not seek clarification of
“isolation stage” in Claim 28. (Docket Entry #72 at 3). On April 23, 2014, the Court allowed
SynQor to amend its infringement claim to assert Claim 28 against Cisco parts containing
regulated converters, as well as unregulated and semi-regulated bus converters (Docket Entry
#72 at 2).
As the term is now contested, Cisco filed an Unopposed Motion for Supplemental
Briefing Regarding Construction of Claim 28, which the Court granted on April 30, 2014. Cisco
submitted an opening claim construction brief on May 8th, 2014, to which SynQor responded on
May 22, 2014. On May 29, 2014, Cisco submitted their reply brief, and SynQor responded with
a surreply brief on June 5, 2014.
Claim 27 of the ‘190 Patent, from which Claim 28 depends, is reproduced below:
A power converter system comprising:
a DC power source;
an isolation stage comprising:
a primary transformer winding circuit having at least one primary winding
connected to the source; and
a secondary transformer winding circuit having at least one secondary
winding coupled to the at least one primary winding; and plural controlled
rectifiers, each having a parallel uncontrolled rectifier and each connected
to a secondary winding, each controlled rectifier being turned on and off
in synchronization with the voltage waveform across a primary winding to
provide an output voltage whose value drops with increasing current flow
through the isolation stage; and
a plurality of non-isolating regulation stages, each receiving the output of the
isolation stage and regulating a regulation stage output.
Claim 28 of the ‘190 Patent is reproduced below:
A power converter system as claimed in claim 27 wherein each primary winding
has a voltage waveform with a fixed duty cycle and transition times which are
short relative to the on-state and off-state times of the controlled rectifiers.
Claim 29 of the ‘190 Patent is reproduced below:
A power converter system as claimed in claim 27 wherein the isolation stage is
II. LEGAL PRINCIPLES
The claims of a patent define the invention to which the patentee is entitled the right to
exclude. Phillips v. AWH Corp., 415 F.3d 1303, 1312 (Fed. Cir. 2005) (en banc). Claim terms
are given their ordinary and customary meaning to one of ordinary skill in the art at the time of
the invention, unless there is clear evidence in the patent’s specification or prosecution history
that the patentee intended a different meaning.
Phillips, 415 F.3d at 1312-13.
construction is informed by the intrinsic evidence: the patents’ specification and file histories.
Id. at 1315-17. Courts may also consider evidence such as dictionary definitions and treatises to
aid in determining the ordinary and customary meaning of claim terms. Phillips, 415 F.3d at
Further, “[o]ther claims, asserted and unasserted, can provide additional instruction
because ‘terms are normally used consistently throughout the patent.’” SmartPhone Techs. LLC
v. Research in Motion Corp., No. 6:10-CV-74-LED-JDL, 2012 WL 489112, at *2 (E.D. Tex.
Feb. 13, 2012) (citing Phillips, 415 F.3d at 1314).
“Differences among claims, such as
additional limitations in dependent claims, can provide further guidance.” Id.
A court should “avoid the danger of reading limitations from the specification into the
claim.” Phillips, 415 F.3d at 1323. For example, “although the specification often describes
very specific embodiments of the invention, [the Federal Circuit has] repeatedly warned against
confining the claims to those embodiments.” Id. The Federal Circuit has “expressly rejected the
contention that if a patent describes only a single embodiment, the claims of the patent must be
construed as being limited to that embodiment.”
This is not only because of the
requirements of Section 112 of the Patent Act, but also because “persons of ordinary skill in the
art rarely would confine their definitions of terms to the exact representations depicted in the
embodiments.” Id. Limitations from the specification should only be read into the claims if the
patentee “acted as his own lexicographer and imbued the claim terms with a particular meaning
or disavowed or disclaimed scope of coverage, by using words or expressions of manifest
exclusion or restriction.” E-Pass Techs., Inc. v. 3Com Corp., 343 F.3d 1364, 1369 (Fed. Cir.
2003) (citations omitted); Thorner v. Sony Computer Entm’t Am. LLC, 669 F.3d 1362, 1367
(Fed. Cir. 2012).
Similarly, the prosecution history may not be used to infer the intentional narrowing of a
claim absent the applicant’s clear disavowal of claim coverage. Superguide Corp. v. DirecTV
Enters., 358 F.3d 870, 875 (Fed. Cir. 2004) (citations omitted). “To be given effect, such a
disclaimer must be made with reasonable clarity and deliberateness.” Id.
Guided by these principles of claim construction, this Court directs its attention to the
disputed claim term.
III. CLAIM CONSTRUCTION
The parties have submitted the following disputed term for construction: “isolation
Plaintiff’s Proposed Construction
Defendants’ Proposed Construction
“A stage that provides isolation.”
“A non-regulating or semi-regulating isolation
This disputed term appears in ‘190 Patent Claim 28, which is dependent upon Claim 27,
and was not addressed in the ‘497 Order. The parties agree that “isolation” means “the absence
of an electric path permitting the flow of DC current (other than a de minim[i]s amount) between
an input and an output of a circular stage, component, or circuit.” (Docket Entry #4 at 34).
Cisco asserts the claim language supports its construction, as omitting “non-regulating”
from “isolation stage” in Claim 27 was intended to distinguish between non-regulating and semiregulating bus converters. (Docket Entry #81 at 2). Cisco cites SynQor’s proposed construction
of Claim 27, which actually contains the “isolating stage” language in the ‘497 case. Id. Cisco
also contends that SynQor asserted the same to the Patent and Trademark Office. (Id.)
Cisco further asserts the “fixed duty cycle” language of Claim 28 precludes a regulated
bus converter. (Docket Entry #72 at 4). Cisco cites the claim language in Claim 27, which
requires “an isolation stage… having at least one primary winding,” and Claim 28, which
requires “each primary winding has a voltage waveform which has a fixed duty cycle.” Id. Both
parties agree a “fixed duty cycle” is “a duty cycle that is not varied to control the output voltage
towards a predefined value.” Id. Cisco points out that “[c]ontrolling an output towards a
predefined value” is “regulating” and “[n]ot controlling an output towards a predefined value” is
“non-regulating.” Id. Accordingly, Cisco claims the isolation stage of Claim 28 precludes
regulation. It argues the patent precludes regulation when the duty cycle is fixed, as “regulation
is by control of the duty cycle.” (Docket Entry #81 at 5). Cisco asserts this precludes regulation
by any other means. Id.
Cisco also asserts SynQor’s previous position is Claim 28 does not apply to regulated bus
converters. (Docket Entry #72 at 5). Cisco references comments by the inventor of the ‘190
Patent confirming that the duty cycle is fixed. Id. (quoting Ex. 8 at 6; Ex. 1 at 11:10-13, 13:9-15,
It contends that SynQor’s position before the PTAB during prosecution and
reexamination is inconsistent with a construction of isolation stage that includes regulated
converters. Id. at 6-9. According to Cisco, SynQor stated down-converting voltage occurred
“through an isolating stage without regulation.” Id. at 6. Cisco highlights the Patent Examiner’s
statement of reasons for allowance with respect to a “non-regulating isolation stage” as critical to
the patent’s issuance. Id. at 6-7. Cisco argues that SynQor made no statement before the Patent
Office that the ‘190 Patent covered regulated bus architectures. Id. at 7-8.
Finally, Cisco asserts judicial estoppel precludes SynQor’s construction, as SynQor failed
to assert regulated converters of infringing in the related ‘497 case. Id. at 9. According to Cisco,
SynQor distinguished the bus converters of Claim 27 from regulated converters. Id. Cisco argues
SynQor should be limited by the construction asserted in the ‘497 case, in which SynQor
excluded regulated converters from Claim 27. Id. at 10. It also cites extrinsic evidence from the
‘497 case to support its claims. Cisco argues SynQor’s proposed construction in the ‘497 case
precludes regulated converters because Claim 27 requires an “output voltage whose value drops
with increasing current flow through the isolation stage.” (Docket Entry #81 at 1). It alleges
SynQor’s own claim construction brief stated that phrase limits the patent to non-regulated and
semi-regulated converters. Id.
In its briefs, SynQor asserts its proposed construction is the ordinary meaning of the term
and is supported by the claim language and the specification. (Docket Entry #79 at 1). SynQor
also argues Cisco never contested SynQor’s construction conforms with the ordinary meaning.
(Docket Entry #82 at 2). SynQor further contends that Cisco’s construction fails to conform to
the claim language or specification. (Docket Entry #79 at 1). According to SynQor, Cisco relies
too heavily on statements during prosecution and reexamination, and none of these statements
qualify as a clear and unambiguous disavowal, which is required for claim construction
SynQor also notes the context does not support additional limitation on “isolation stage.”
Id. at 2. Because Claim 27 does not explicitly mention non-regulation or semi-regulation as
Claims 1, 20, and 29 do, SynQor asserts “isolation stage” should not be so limited. (Docket Entry
#79 at 3; Docket Entry #82 at 2). SynQor also quotes Judge Ward’s Claim Construction Order in
the ‘497 case which stated limitations on “isolation stage” were done expressly; therefore the
lack of express requirement in Claim 28 should not limit the phrase. (Docket Entry #79 at 1).
SynQor also asserts the doctrine of claim differentiation supports their claim
construction. Id. at 3. According to SynQor, Claim 29, like Claim 28, is dependent upon Claim
27, and Claim 29 explicitly requires “the isolation stage is non-regulating.” Id. (quoting Ex. 6 at
19:16-17). According to SynQor, this strongly implies that “isolation stage” is not limited, as
“claim differentiation” is “clearly applicable” where the added limitation “is the only meaningful
difference between two claims.” Id. (quoting Wenger Mfg., Inc. v. Coating Mach. Sys., Inc., 239
F.3d 1225, 1233 (Fed. Cir. 2001)).
SynQor also asserts Cisco’s argument conflating “fixed duty cycle” and “isolation stage”
is erroneous. (Docket Entry #79 at 4; Docket Entry #82 at 2). According to SynQor, “fixed duty
cycle” is a different limitation from “isolation stage.” (Docket Entry #79 at 4-5). SynQor notes
that some claims including “isolation stage” do not include “fixed duty cycle,” such as Claims
20-27 and Claim 29. Id. at 4. Furthermore, SynQor claims that regulation may be done by means
alternative to the duty cycle. Id. According to SynQor, the ‘190 Patent specification states
regulation may be done using the synchronous rectifier MOSFETs. Id. at 5-6 (citing Ex. 1 at
SynQor asserts statements during the prosecution history only limit a claim when they
constitute a “clear and unmistakeable surrender of subject matter.” Id. at 4 (quoting Ecolab, Inc.
v. FMC Corp., 569 F.3d 1335, 1342 (Fed. Cir. 2009)). SynQor argues none of the statements
made during prosecution were “clear and unmistakeable surrender,” necessary for limitations.
(Docket Entry #79 at 6-7; Docket Entry #82 at 3). Furthermore, SynQor asserts the statements
referenced by Cisco were taken out of context and mischaracterized. (Docket Entry #79 at 7-8).
According to SynQor, many of these quotes referencing non-regulated and semi-regulated
architectures were not intended to limit claims to those types of architectures, but rather to
include the discussed architecture types. (Docket Entry #79 at 8-9; Docket Entry #82 at 3).
SynQor also argues that judicial estoppel is inapt as “isolation stage” was not the
contested language in the ‘497 case. (Docket Entry #79 at 9). Additionally, SynQor asserts Judge
Ward rejected their construction. Id.
In Claim 27, “isolation stage” is preceded by no limitations pertaining to regulation.
(‘190 Patent, 18:62). This stands in contrast to Claims 1 and 20, which both require a “nonregulating isolation stage.” (‘190 Patent, 17:24, 18:31). This strongly implies that “isolation
stage” is at least not limited to “non-regulating” converters. Furthermore, Claim 29 requires that
the isolation stage is non-regulating. While this requirement may be intended to differentiate
from “semi-regulating,” as asserted by Cisco, there is nothing in the claim language to imply
“isolation stage” is limited to only non-regulating or semi-regulating architectures. Furthermore,
it implies that a “non-regulating” requirement was purposely withheld in Claim 27. Had SynQor
intended for isolation stage to be limited to non-regulating and semi-regulating configurations
only, the inventor could have limited the claim to those two configurations in Claim 27 as it did
to a single configuration in Claims 1 and 20. Accordingly, claim language does not support
limitation of “isolation stage.”
Cisco’s argument that a fixed duty cycle precludes a regulated converter is not
persuasive. “Isolation stage” is used in Claims 20-27 and 29 without including a fixed duty cycle
limitation, indicating those limitations operate independently. The specification also indicates
that regulation may be achieved through means other than the duty cycle. Furthermore, the
Federal Circuit frowns upon reading limitations into claims based on the specification. Phillips,
415 F.3d at 1323. Additionally, the quote Cisco cites is taken out of context and applies to a
particular configuration shown in Figure 2, rather than all possible configurations, and thus
should not limit Claim 28. Accordingly, “fixed duty cycle” does not limit “isolation stage.”
Despite Cisco’s contention that the ‘190 Patent prosecution history constitutes limitations
upon “isolation stage,” these statements are ambiguous and were construed by both parties to
support their constructions. Limitation of the patent claims requires “a clear and unmistakable
surrender of subject matter.” Ecolab, Inc. v. FMC Corp., 569 F.3d 1335, 1342 (Fed. Cir. 2009)
(citing Bayer AG v. Elan Pharm. Research Corp., 212 F.3d 1241, 1251 (Fed. Cir. 2000)).
Because SynQor’s previous statements are ambiguous, the prosecution history does not support
the assertion of “clear and unmistakable surrender” by SynQor. Accordingly, the prosecution
history does not support limitation of “isolation stage” to preclude regulated converters.
The intrinsic evidence thus supports SynQor’s position. Further, the extrinsic evidence
cited by Cisco does not overcome the intrinsic record. In the ‘497 case, the arguments related to
the term “output voltage whose value drops with increasing current flow.” This term is different
and separate from the “isolation stage” that is now before the Court. Also, in the ‘497 case the
Court rejected the arguments of the parties and found that the “output voltage whose value drops
with increasing current flow” required no further construction. As noted by the court in the ‘497
. case, “[w]hen the claims were intended to limit the claims to an isolation stage as being ‘non-
regulated,’ the claims do so by expressly using the term ‘non-regulating.’” ‘497 case, Docket
Entry # 474 at 36. The voltage drop term remains a limitation of the ‘190 Patent, but it does not
change the separate “isolation stage” term. Moreover, the change Cisco seeks to the “isolation
stage” may render the voltage drop term superfluous. Cisco’s extrinsic evidence does not
overcome the clear language of the claims nor the intrinsic record as a whole.
The Court therefore construes “isolation stage” to have its plain and ordinary meaning.
IT IS SO ORDERED.
SIGNED this 11th day of July, 2014.
CAROLINE M. CRAVEN
10 UNITED STATES MAGISTRATE JUDGE
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