PTAB

IPR2021-00067

Fantasia Trading LLC v. CogniPower LLC'S

Log In
Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Power Converter with Demand Pulse Isolation
  • Brief Description: The ’031 patent describes a switched-mode power converter with primary and secondary control circuits separated by a galvanic isolation barrier (e.g., a transformer). The secondary-side circuit regulates the output voltage by sending "demand pulses" across the barrier to the primary-side circuit, which controls a power switch. A key aspect is a secondary bias circuit using a rectifier "poled to charge a capacitor during forward pulses" to power the secondary controller.

3. Grounds for Unpatentability

Ground 1: Obviousness over Zhu in view of Mao

  • Prior Art Relied Upon: Zhu (Application # 2011/0096573) and Mao (Patent 6,466,461).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that during the reissue prosecution that led to the ’031 patent, the examiner found that Zhu disclosed the core architecture of the invention—a switched-mode power converter with primary and secondary controllers where the secondary controller sends demand pulses across an isolation barrier to regulate the output. The claims were only allowed after being amended to add a specific secondary bias circuit powered by "forward pulses." Petitioner argued that this specific bias circuit was well-known and explicitly taught by Mao, which discloses an improved bias circuit that uses a rectifier poled to charge a capacitor during the forward phase (when the primary switch is on). The combination of Zhu’s control architecture with Mao’s forward-based bias circuit allegedly rendered the challenged claims obvious.
    • Motivation to Combine: Petitioner argued a person of ordinary skill in the art (POSITA) would combine Mao with Zhu to solve a known problem. Zhu’s secondary controller is powered from the main output voltage, making it susceptible to fluctuations and unreliable at very low output voltages or in constant-current applications. Mao was directed specifically to providing a more stable bias voltage source that is less vulnerable to such variations. A POSITA would therefore have been motivated to replace Zhu’s simple bias circuit with Mao’s improved, forward-based design to enhance reliability and broaden the converter’s operating range.
    • Expectation of Success: A POSITA would have had a high expectation of success because the combination involved substituting a known, improved sub-circuit (Mao's bias supply) into a conventional power converter architecture (Zhu's) to achieve predictable benefits.

Ground 2: Obviousness over Szepesi in view of Mao

  • Prior Art Relied Upon: Szepesi (Patent 5,498,995) and Mao (Patent 6,466,461).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground presented a parallel argument to Ground 1. Petitioner contended that the reissue examiner also found that Szepesi disclosed the fundamental two-controller architecture, wherein a primary controller starts the converter and a secondary controller takes over to regulate the output by sending control pulses across an isolation barrier. Like Zhu, Szepesi’s disclosure lacked the specific forward-based bias circuit that was added to secure allowance of the claims. Szepesi's secondary controller derives its bias power from the flyback output. Petitioner argued that combining Szepesi’s converter with the forward-based bias circuit taught by Mao would render the claims obvious.
    • Motivation to Combine: The motivation was identical to that asserted for the Zhu combination. The bias circuit in Szepesi, being dependent on the output, suffered from the same well-understood limitations related to output voltage fluctuations. Mao taught a solution to this exact problem. A POSITA would have been motivated to incorporate Mao’s robust bias circuit into Szepesi’s design to improve performance and operational stability, particularly for applications requiring low output voltages or constant-current operation.
    • Expectation of Success: Success was expected because it involved applying a known solution from Mao to a known problem in Szepesi’s architecture using standard design principles.

4. Arguments Regarding Discretionary Denial

  • Petitioner argued that the Board should not exercise its discretion to deny institution under §314(a) based on the Fintiv factors. Petitioner asserted that the co-pending district court litigation was in its very early stages, with a trial date set for well after the statutory deadline for a Final Written Decision (FWD) in the IPR. It was argued that investment in the litigation was minimal, no claim construction had occurred, and Petitioner was willing to stipulate not to pursue the same invalidity grounds in district court, thereby avoiding duplicative efforts.

5. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claims 1, 2, 8, 10, 18, 25, 27, 30-33, 37-38, 40, 43-46, 49, 52-55, and 58-61 of the ’031 patent as unpatentable.