PTAB

IPR2017-01328

Power Integrations Inc v. Semiconductor Components Industries LLC

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: FLYBACK CONVERTER
  • Brief Description: The ’019 patent discloses a flyback DC-DC converter that regulates output voltage. The system is designed to detect the output voltage from the primary side of a transformer, using a feedback unit to correct for load-dependent errors without requiring a traditional photocoupler for galvanic isolation.

3. Grounds for Unpatentability

Ground 1: Anticipation over Bonte - Claims 1-15 are anticipated by Bonte under 35 U.S.C. § 102.

  • Prior Art Relied Upon: Bonte (Patent 5,305,192).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Bonte, a reference not considered during the original prosecution, discloses every element of challenged claims 1-15. The petition provided a detailed, element-by-element mapping for each limitation of independent claim 1. Specifically, Petitioner asserted that Bonte's FIG. 4A discloses a flyback converter with a transformer (401), an output unit (diode D1, capacitor C1), a switch (412), and a comprehensive feedback unit (414).
    • The core of the argument focused on the feedback unit, as its detailed structure was added to the claims during prosecution to overcome a rejection. Petitioner argued Bonte’s feedback unit performs the identical functions claimed in the ’019 patent. Bonte’s "load regulation compensation circuit" (FIG. 8, element 800), which includes a current amplifier (801) functioning as a gain regulator, was shown to detect the switching current to adjust the feedback signal. This adjustment compensates for errors in output voltage detection caused by parasitic impedances, thereby meeting the claim limitation of "detecting a switching current of the switch to correct the feedback signal."
    • Petitioner mapped other key components of the claimed feedback unit to Bonte's circuits, including the "switch current operator" (Peak Detector 670 and resistor 625), the "gain regulator" (current amplifier 801 in FIG. 8), and the "feedback signal generator" (sampling error amplifier 610 and associated circuitry). Petitioner contended that Bonte explicitly teaches using these components to generate a corrected feedback signal (VC) that controls the switching controller, anticipating the structure and function of the ’019 patent’s claims.
    • For the dependent claims, Petitioner argued that Bonte’s detailed circuit diagrams and specification likewise disclosed the additional limitations. For example, claim 2’s specific driving power generator components were mapped to elements in Bonte's FIG. 5 and FIG. 7, and claim 4’s feedback signal generator components were mapped to resistor 505 and capacitor 730 in Bonte. This systematic mapping was extended to all 15 challenged claims.

4. Key Claim Construction Positions

  • Petitioner argued for the broadest reasonable interpretation of key functional terms, asserting these constructions were consistent with the ’019 patent’s specification and aligned with the disclosures in Bonte.
  • "correct the feedback signal" (Claims 1, 5, 14, 15): Petitioner proposed this term should be construed to mean "to adjust the feedback signal to compensate for errors in the output voltage detection." This construction was based on the ’019 patent’s stated purpose of providing a constant output voltage even as the load condition varies. Petitioner argued Bonte’s "load compensation circuit" explicitly performs this function.
  • "generate a corrected current signal" (Claims 1, 5): Petitioner proposed this term should be construed as "using the converted current signal to generate a proportional corrected current signal." This was based on the ’019 patent’s description of a gain regulator (140) that scales a converted current signal (Iscp) by a gain (GM). Petitioner contended this describes a standard amplifier function, which is precisely what Bonte’s current amplifier (801) is described as doing.

5. Relief Requested

  • Petitioner requests institution of an inter partes review (IPR) and cancellation of claims 1-15 of the ’019 patent as unpatentable.