PTAB

IPR2018-00381

Power Integrations Inc v. Semiconductor Components Industries LLC

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Offline Synchronous Switching Regulator
  • Brief Description: The ’923 patent relates to offline synchronous switching regulators used in power supplies. The technology involves using a synchronous rectifying circuit integrated with the regulation circuit to improve efficiency, including a transformer, primary-side switches, and a secondary-side synchronous switch comprising a power-switch set and a control circuit.

3. Grounds for Unpatentability

Ground 1: Claims 1, 2, 4, 5, 10-13, and 15 are obvious over Havanur in view of IR2110

  • Prior Art Relied Upon: Havanur (Patent 6,788,554) and IR2110 (International Rectifier IR2110 High and Low Side Driver Data Sheet).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Havanur taught a switched-mode power converter that included nearly all elements of the challenged claims, such as synchronous rectification and secondary-side post-regulation. Havanur’s circuit (FIG. 4) disclosed a transformer, primary-side switches, and a secondary-side power-switch set (MOSFETs 52, 54) in a high-side configuration. However, Havanur used a discrete gate drive transformer (86) to couple its control logic (60) to the high-side power switches. Petitioner contended that the IR2110 datasheet, which described a standard high-side driver integrated circuit (IC), supplied the missing "control circuit" limitation of the claims.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine Havanur with IR2110 to improve the design. Petitioner asserted that replacing a bulky, custom-designed gate drive transformer like Havanur's with a smaller, standard, off-the-shelf driver IC like IR2110 was a well-known and desirable design choice. This substitution would reduce circuit board area, lower component and design costs, and simplify the overall circuit. The petition cited another reference, SLUP169, to support the argument that this interchangeability between transformer-coupled gate drives and IC-based gate drives was a common practice in the field.
    • Expectation of Success: A POSITA would have a high expectation of success because the combination involved substituting one known functional block (a transformer gate drive) with another well-known functional block (an IC gate drive) to achieve predictable and advantageous results. The integration would be a straightforward implementation of a standard component for its intended purpose.

Ground 2: Claims 1, 4, 5, 10-13, and 15 are obvious over SC4910 in view of IR2110

  • Prior Art Relied Upon: SC4910 (SEMTECH SC4910A/B High Performance Secondary Side Controller Datasheet) and IR2110 (International Rectifier IR2110 High and Low Side Driver Data Sheet).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that the SC4910 datasheet disclosed an integrated secondary-side controller for use in isolated switch-mode power supplies with synchronous rectification. SC4910 taught a controller that receives a switching signal and a feedback signal to generate pulse signals for driving power switches. However, the exemplary circuits in SC4910 showed a synchronous rectifier in a low-side configuration (i.e., coupled between the transformer secondary and ground), whereas the ’923 patent claimed a high-side configuration (coupled between the transformer secondary and the output).
    • Motivation to Combine: A POSITA would have found it obvious to modify the SC4910 circuit to use a high-side switching topology, as both low-side and high-side configurations were well-known alternatives with understood trade-offs. To implement this predictable high-side configuration, a POSITA would need a high-side gate driver. Petitioner asserted that it would have been obvious to use a standard, well-known high-side driver IC like IR2110 to drive the reconfigured high-side power switch. This combination would allow a designer to leverage the controller features of SC4910 in a common high-side topology.
    • Expectation of Success: A POSITA would have a reasonable expectation of success in this combination. The modification involved implementing a known circuit topology (high-side) as an alternative to another (low-side) and using a standard component (IR2110) designed specifically for the required function (driving a high-side switch). This constituted a predictable design choice rather than an inventive step.

4. Relief Requested

  • Petitioner requests the institution of an inter partes review (IPR) and the cancellation of claims 1, 2, 4, 5, 10-13, and 15 of the ’923 patent as unpatentable under 35 U.S.C. §103.