PTAB

IPR2018-00166

On Semiconductor Corp v. Power Integrations Inc

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Switching Power Converters
  • Brief Description: The ’623 patent relates to switching power converters that use a "digital" feedback scheme. The patented system enables or disables a regulator circuit based on whether an output voltage is above or below a threshold level, purporting to overcome disadvantages of traditional pulse-width modulation (PWM) designs.

3. Grounds for Unpatentability

Ground 1: Obviousness over Barbehenn and Grebene - Claims 1, 2, and 5 are obvious over Barbehenn in view of Grebene.

  • Prior Art Relied Upon: Barbehenn (Patent 5,914,865) and Grebene (a 1984 textbook titled Bipolar and MOS Analog Integrated Circuit Design).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Barbehenn discloses a simplified AC-DC switching converter with a "bang-bang" control architecture. This architecture uses an "industry standard" 555 timer as an oscillator to drive a power FET switch. A feedback loop, including an optocoupler, inhibits the 555 timer's oscillation when the output voltage exceeds a set threshold. Grebene, a standard textbook, provides the well-known internal circuitry and block diagrams for the CMOS version of the 555 timer, which Barbehenn suggests can be used. The combination of Barbehenn’s circuit and Grebene’s details on the timer’s internal components allegedly discloses every element of claims 1, 2, and 5, including the regulator circuit comprising a feedback input, switch, and oscillator on a monolithic device.
    • Motivation to Combine: Petitioner contended that because Barbehenn explicitly identifies its core component as an "inexpensive 555 timer oscillator," a POSITA would have been directly motivated to consult a standard, authoritative reference like Grebene to understand its internal workings for implementation, modification, or integration.
    • Expectation of Success: A POSITA would have had a high expectation of success, as the combination merely involved applying well-documented, standard information about a common component to the exact type of circuit for which it was designed.

Ground 2: Obviousness over Barbehenn, Grebene, and the '369 Patent - Claims 5-7 are obvious over Barbehenn and Grebene in view of the ’369 Patent.

  • Prior Art Relied Upon: Barbehenn (Patent 5,914,865), Grebene (1984 textbook), and the '369 Patent (Patent 5,285,369).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground builds upon the combination in Ground 1 to further address the limitations of dependent claims 6 and 7. These claims recite a bypass output, a capacitor coupled to it, and a current source coupled between the switch and the bypass output to power the regulator. Petitioner argued the ’369 patent, which was assigned to the Patent Owner, expressly teaches this feature. The ’369 patent discloses using a low-voltage tap point within a high-voltage power MOSFET, where a JFET portion of the MOSFET acts as a current source to supply power to the internal control circuitry and charge an external bypass capacitor.
    • Motivation to Combine: Petitioner asserted two primary motivations. First, a POSITA would combine Barbehenn with the ’369 patent to solve a known problem, as Barbehenn requires a low-voltage supply for its control circuit but does not disclose its source. The ’369 patent offers a known, efficient technique for providing this power. Second, a POSITA would be motivated to adopt the ’369 patent’s technique to achieve the recognized benefits of reduced component count, pin count, and cost, which are common objectives in integrated circuit design.
    • Expectation of Success: Integrating the ’369 patent's established power supply method into Barbehenn's controller would be a predictable application of a known technique to improve a similar device.

Ground 3: Anticipation by Motorola - Claims 1-5 are anticipated by Motorola.

  • Prior Art Relied Upon: Motorola (MC34163/MC33163 Datasheet).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner argued the Motorola datasheet for its MC34163 series of regulators anticipates every element of claims 1-5. The datasheet describes a "monolithic power switching regulator" (anticipating claim 5) containing all primary functions for a DC-to-DC converter. It discloses a feedback input (Pin 3), a high-current output switch (transistor Q2, anticipating claim 2), and a "controlled duty cycle oscillator." The device's internal logic, including a feedback comparator, enables and disables the switch based on the feedback signal. Further, Motorola discloses an over-current limit comparator that monitors switch current and terminates switch operation on a cycle-by-cycle basis when a current limit is exceeded, anticipating the "over current blockregulator" limitations of claims 3 and 4.

  • Additional Grounds: Petitioner asserted additional obviousness challenges, including grounds based on an alternative embodiment within Barbehenn alone (Ground 3), combinations of Barbehenn and the '369 Patent (Ground 4), an alternative mapping of Motorola (Ground 6), and combinations of Barbehenn and Motorola (Grounds 7 and 8).

4. Key Claim Construction Positions

  • "comprises a monolithic device": Petitioner argued this phrase from claim 5 should be construed according to its plain and ordinary meaning as "including a monolithic device." Under this construction, the claim would not require all previously recited elements of the regulator circuit (such as the switch and oscillator) to be integrated onto that single monolithic device, creating an open-ended claim consistent with the legal precedent for the term "comprising."

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-7 of the '623 patent as unpatentable.