PTAB must evaluate district court claim construction to determine whether it is consistent with BRI

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Federal Circuit Review – Issue No. 64-03
USPTO Board Must Set Out Sufficient Reasoning for Meaningful Appellate Review

Power Integrations, Inc. v. Lee, No. 2014-1123, 2015 U.S. App. LEXIS 14077 (Fed. Cir. Aug. 12, 2015) (Before Moore, Mayer, and Linn, J.) (Opinion for the court, Mayer, J.). Click Here for a copy of the opinion.

Power Integrations (“PI”) sued Fairchild Semiconductor International and related parties (“Fairchild”) for willfully infringing its patents related to a technique for reducing electromagnetic interference by jittering the switching frequency of a switched mode power supply. The relevant claim language requires “the digital to analog converter coupled to the counter, the counter causing the digital to analog converter to adjust the control input and to vary the switching frequency of the power supply.” The district court adopted PI’s claim interpretation and construed “coupled” to require “that the two circuits be connected in a manner such that voltage, current, or control signals pass from one to another.’” The court agreed, that “coupled” did not “require a direct connection or … preclude the use of intermediate circuit elements.”

While litigation was pending, the Patent Office granted Fairchild’s request for ex parte reexamination of the asserted claims. PI urged the Board to adopt the district court’s claim construction. The Board concluded, like the district court, that “coupled to” did not preclude intervening components.  Because prior art disclosed a programmed memory between the counter and the digital to analog converter, the asserted claims were found to be anticipated. However, the Board did not address that the “coupled” connection, whether direct or indirect, must allow voltage, current, or control signals pass between them.

PI filed a request for rehearing, arguing that the Board “had ‘misapprehended’ its argument regarding the proper construction of the term ‘coupled to.’” The Board denied PI’s request and maintained that the claims were anticipated. PI then challenged the Board’s decision in the district court. After determining that it lack subject matter jurisdiction, the district court transferred to the case to the Federal Circuit.

The Federal Circuit held that “the [B]oard fundamentally misconstrued [PI’s] principal claim construction argument and failed to provide a full and reasoned explanation” of its anticipation rejection. The critical issue was whether the claims require (1) the counter itself or (2) the counter and a memory functioning together to drive the digital to analog converter, i.e. a controlling voltage, current or signal. The Board’s decision, however, focused only on whether there can be intervening components between the counter and the digital to analog converter. The Board also failed to evaluate PI’s main argument that “the ‘coupled’ limitation requires that the counter pass control signals, voltage, or current to the digital to analog converter to control it, and that the presence of a memory programmed with data specifying how to vary the switching frequency ‘uncouples’ the counter and the digital to analog converter and severs the requisite control relationship between them.”

Furthermore, even though the Board is generally not bound by the district court’s construction of claim terms, it does not mean that “it has no obligation to acknowledge that interpretation or to assess whether it is consistent with the broadest reasonable construction of the term.” Here, given that PI’s main argument was the proper interpretation of the term “coupled,” which was construed by the district court, the Board had an obligation “to evaluate that construction and to determine whether it was consistent with the broadest reasonable construction of the term.” Because the Board failed to address the district court’s interpretation of the term “coupled” and failed to provide adequate explanation for its decision to reject the claims as anticipated, the Court reversed and remanded.


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