By Mark Engstrom, J.D.
In a consolidated appeal of two PTAB decisions following inter partes reexaminations of two SynQor patents on similar inventions involving an architecture for power converters, the U.S. Court of Appeals for the Federal Circuit affirmed in part and vacated in part the rejection and non-rejection decisions of the Board. The rulings in the respective reexaminations contained inconsistent findings on identical issues and the same record, the court explained, even though they shared a common panel that had issued both opinions on the same date (Vicor Corp. v. SynQor, Inc., August 30, 2017, Chen, R.).
Inventions. SynQor owned U.S. Patent Nos. 8,023,290 and 7,272,021 (the "SynQor Patents"), which were directed to a particular architecture for "direct current" to "direct current" power converters. Vicor Corporation successfully requested inter partes reexamination of both SynQor patents. The reexaminations ultimately were decided by the Board. Vicor appealed the Board’s decision in the ’290 reexamination (which held that certain claims were patentable over prior art combinations that were proposed by Vicor) and SynQor appealed the Board’s decision in the ’021 reexamination (holding that certain claims were unpatentable as anticipated or obvious).
The Federal Circuit court noted that a "DC to DC" converter received DC output from a front- end converter and transformed it into one or more "lower DC" voltages. The converters claimed in the SynQor patents performed two general operations in sequence: isolation and regulation. Isolation converted a DC input into AC, reduced the AC voltage using a transformer, and used "controlled" rectifiers to convert AC back to DC at a voltage that was lower than the DC input. Thereafter, regulation restricted the isolated output to a DC voltage that was appropriate for driving the relevant circuitry. According to SynQor, the patents improved prior art systems by: (1) separating the isolation and regulation functions of DC to DC converters into two steps and (2) using a single isolation stage to drive multiple regulation stages. Because the single isolation stage drove an "intermediate bus" that was fed to multiple on-board regulator components, SynQor’s two-stage architecture became known as "Intermediate Bus Architecture" (IBA).
The sole independent claim of the ’290 patent—claim 1—covered an IBA converter that was implemented with switching regulators. Claim 1 of the ’021 patent was very similar to claim 1 of the ’290 patent, but the former claim included the limitation "substantially uninterrupted flow of power," which was present in all of the claims of the ’021 patent. Prior proceedings involving the same or similar patents included SynQor’s 2007 infringement suit against major competitors; an reexamination of SunQor’s U.S. Patent No. 7,072,190, requested by Murata Manufacturing; and a second reexamination of the same patent, requested by Vicor.
Reexamination of ’290 patent. In 2011, the PTO granted Vicor’s request for reexamination of the ’290 patent and adopted Vicor’s proposed grounds for rejection. Rejections I–II held that 15 claims were obvious over Steigerwald ’090, Cobos, and Pressman; Rejections III–IV held that the same claims were obvious over JP ’446, Steigerwald ’539, and Kassakian; and Rejections V–VI held that the same claims were obvious over Steigerwald and Pressman.
After the Board issued its decision in the Murata reexamination, the examiner withdrew all of its rejections and adopted the Board’s positions that: (1) Steigerwald ’090 and Cobos could not be combined for Rejections I and II because of "frequency incompatibility" between the references’ circuits; (2) a person of ordinary skill in the art would not have been motivated to combine Steigerwald and Pressman for rejections V–VI because Steigerwald taught away from incorporating Pressman’s switching regulators; and (3) all of the challenged claims were "not obvious based on objective indicia of non-obviousness." With respect to Rejections III–IV, the examiner relied exclusively on evidence of secondary considerations in withdrawing the rejections involving Vicor’s proposed combination of JP ’446, Steigerwald ’539, and Kassakian, and it did so without addressing three of the four "Graham" factors that were set forth in Graham v. John Deere Co. of Kansas City, 383 U.S. 1 (1966). The unaddressed factors were: (1) the scope and content of the prior art; (2) the differences between the prior art and the claims at issue; and (3) the level of ordinary skill in the pertinent art. Vicor appealed to the Board and the Board affirmed the examiner.
Proposed Rejections I and II. The Board found that a skilled artisan would not have been motivated to combine Steigerwald ’090 and Cobos because of "operating frequency incompatibilities" between the references’ circuits. Because Cobos was the only reference that was relied on to supply the controlled rectifiers that were required in all of the claims of the ’290 patent, and in light of other findings, the Federal Circuit affirmed the Board’s decision not to adopt Proposed Rejections I and II.
Proposed Rejections III–IV. The Board affirmed the examiner’s decision to withdraw Proposed Rejections III and IV based solely on SynQor’s proffered objective evidence of non-obviousness. The Board held that: (1) the claims of the ’290 patent covered the same IBA design that was disclosed by the patents in SynQor, Inc. v. Artesyn Techs., Inc., 709 F.3d 1365 (Fed. Cir. 2013), and (2) a nexus existed between the objective evidence and the disputed claims of the ’290 patent.
The Federal Circuit concluded that the Board’s decision on Proposed Rejections III and IV was erroneous, and thus had to be vacated, for two reasons. First, when it looked exclusively at the objective evidence, the Board had improperly analyzed Vicor’s obviousness arguments under just one of the four Graham factors, and it failed to consider the remaining factors and their relative strength. Second, the Board reached inconsistent conclusions—without justification—on the evidentiary weight accorded to secondary considerations that the evidence had presented in the ’290 and ’021 reexaminations. For those reasons, the Federal Circuit vacated the Board’s decisions on Proposed Rejections III and IV and remanded the matter for further proceedings.
Proposed Rejections V-VI. In the reexamination of SynQor’s ’290 Patent, the Board ruled that it would not have been obvious to use Pressman’s switching regulators for Steigerwald’s regulation stage. On the same day, however, the Board reached the opposite conclusion on the same issue in the ’021 reexamination on essentially the same record. Because the Board failed to provide a reasoned explanation for those inconsistent results, the Federal Circuit vacated and remanded the Board’s decision on Proposed Rejections V and VI in the ’290 reexamination and Rejections III and IV in the ’021 reexamination. The Board was directed to reconsider the weight accorded to SynQor’s "secondary considerations evidence" in the respective reexaminations of the SynQor Patents. Reconsideration would properly include an analysis of whether, for Proposed Rejections V–VI, a nexus existed between the secondary considerations evidence and the switching regulators at issue.
Reexamination of the ’021 patent. In 2011, the PTO granted Vicor’s request for reexamination of the ’021 patent and adopted Vicor’s proposed rejections. SynQor added claims 49 and 50 during the reexamination. The added claims required the use of switching regulators. Rejection I held that ten claims were anticipated by Steigerwald; Rejection II held that seven claims were obvious over Steigerwald, in view of the knowledge of a skilled artisan; Rejection III held that claim 49 was obvious over Steigerwald and Pressman; and Rejection IV held that claim 50 was obvious over Steigerwald, Pressman, and the admitted prior art. SynQor appealed and the Board affirmed all four rejections.
Rejection I. SynQor raised two arguments to challenge the Board’s finding that Steigerwald anticipated multiple claims of the ’021 patent: (1) the Board had improperly relied on a new and erroneous ground of rejection on rehearing and (2) the Board had erred by "failing to consider SynQor’s argument that Steigerwald does not teach ‘substantially uninterrupted’ power flow in the alternative synchronous rectifier embodiment" due to the timing of the synchronous rectifiers. Both of those arguments were rejected as unpersuasive, and the Board’s holding of anticipation by Steigerwald was affirmed.
Rejection II. The Board ruled that six claims of the ’021 patent, which included voltage-range limitations, would have been obvious because a skilled artisan would have "implemented those voltages as the result of routine design choice for a circuit for use in particular operating environments." The Federal Circuit found that the Board’s decision on those claims was supported by substantial evidence. Regarding "secondary considerations evidence" that SynQor had presented in connection with those claims, the Board’s finding that such evidence was "principally" directed to features of the anticipated independent claims, and thus was properly accorded a diminished probative value, was supported by substantial evidence. The Board’s decision on Rejection II was therefore affirmed.
Rejections III and IV. For the reasons previously proffered in the court’s discussion of the ’290 reexamination, the Federal Circuit vacated the Board’s decision on Rejections III and IV and remanded the matter for reconsideration of whether the incorporation of Pressman’s switching regulators into Steigerwald’s circuit would have been obvious to a skilled artisan.
The case is Nos. 2016-2283 and 2016-2288.
Attorneys: Matthew A. Smith (Smith Baluch LLP) for Vicor Corporation. Thomas D. Rein (Sidley Austin LLP) for SynQor, Inc.
Companies: Vicor Corp.; SynQor, Inc.
MainStory: TopStory Patent FedCirNews
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