PTAB

IPR2021-00071

Fantasia Trading LLC v. CogniPower LLC

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: POWER CONVERTER WITH DEMAND PULSE ISOLATION
  • Brief Description: The ’713 patent describes a switched-mode power converter with galvanically isolated primary and secondary control circuits. The secondary circuit regulates the output voltage by sending "demand pulses" across an isolation barrier to control the switching of the primary-side power switch. A key claimed feature is the method of powering the secondary circuit using a rectifier poled to charge a capacitor during "forward pulses" of the power converter.

3. Grounds for Unpatentability

Ground 1: Claims 18-23, 25, 30-31, 34-36, 41-43, 45, and 48-51 are obvious over Zhu and Mao.

  • Prior Art Relied Upon: Zhu (Application # 2011/0096573) and Mao (Patent 6,466,461).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Zhu disclosed the core architecture of the challenged claims, including a flyback converter with isolated primary and secondary control circuits. In Zhu, the secondary circuit senses the output voltage and transmits demand pulses to the primary controller to regulate the output by adjusting the switching frequency. However, Zhu’s secondary circuit is powered conventionally from the output voltage via a flyback winding. Mao was presented as teaching the exact element that led to the allowance of the ’713 patent: an improved bias circuit for a secondary controller that uses a rectifier poled to charge a capacitor during the forward phase (when the primary switch is on), making it less vulnerable to input or output voltage variations.
    • Motivation to Combine: Mao expressly taught that conventional bias circuits, like the one in Zhu, are susceptible to undesirable fluctuations. A person of ordinary skill in the art (POSITA) would combine Mao’s well-known, improved forward-based bias circuit with Zhu’s power converter to improve performance and reliability, particularly for applications requiring low output voltages or constant-current operation where the output voltage might drop too low to reliably power the secondary circuit.
    • Expectation of Success: A POSITA would have a reasonable expectation of success because combining Mao’s bias supply—a known solution for improving secondary-side power stability—with Zhu’s standard converter architecture involved applying known principles to achieve a predictable result.

Ground 2: Claims 18-23, 25, 30-31, 35-36, 41-42, 45, and 48-51 are obvious over Szepesi and Mao.

  • Prior Art Relied Upon: Szepesi (Patent 5,498,995) and Mao (Patent 6,466,461).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner asserted that Szepesi, like Zhu, disclosed the fundamental two-controller architecture of the ’713 patent. Szepesi described an isolated switched-mode power supply where a secondary controller takes over from a primary controller at startup and sends pulses through a pulse transformer to control the primary switch. Szepesi’s secondary controller also derives its bias power from the flyback output. The petition argued for replacing Szepesi’s conventional bias circuit with the improved forward-based bias circuit taught by Mao to meet all limitations of the independent claims.
    • Motivation to Combine: The motivation was identical to that asserted in Ground 1. Mao taught a solution to the known problem of unstable bias voltage in circuits like Szepesi’s. A POSITA would be motivated to incorporate Mao's teachings to improve the Szepesi converter's robustness and expand its applicability to a wider range of operating conditions, such as low-voltage or constant-current modes.
    • Expectation of Success: The combination was argued to be a predictable substitution of one known functional block (a conventional bias circuit) with an improved, known alternative (Mao's forward-based bias circuit) to gain its known advantages.

  • Additional Grounds: Petitioner asserted an additional obviousness challenge (Ground 3) against claims 18, 22-23, 25, 30, 34, 41-43, 45, and 48-51 based on Matsumoto (Patent 7,773,392) in view of Mao, relying on a similar motivation to replace a conventional secondary bias supply with Mao's improved forward-based circuit.

4. Arguments Regarding Discretionary Denial

  • Petitioner argued that the Board should not exercise discretionary denial under 35 U.S.C. §314(a) based on the Fintiv factors. The petition asserted that the co-pending district court litigation was in a very early stage, with a trial date set for May 2022, well after a Final Written Decision (FWD) would issue in the IPR. Petitioner also contended that its investment in preparing the IPR outweighed the resources expended in the nascent litigation and offered to stipulate not to pursue the same invalidity grounds in district court if the IPR was instituted, thereby preventing duplicative efforts.

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 18-23, 25, 30-31, 34-36, 41-43, 45, and 48-51 of the ’713 patent as unpatentable.