PTAB

IPR2019-00104

Kingston Technology Co Inc v. North Star Innovations Inc

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Key Events
Petition

1. Case Identification

2. Patent Overview

  • Title: Complimentary Double Pumping Voltage Boost Converter
  • Brief Description: The ’875 patent describes a "double pumping" voltage boosting circuit, also known as a charge pump, designed to produce an output voltage greater than its input supply voltage. The invention aims to reduce output voltage "ripple" by using two parallel boosting circuits that operate with opposite phase signals, thereby providing a smoother and more continuous output voltage.

3. Grounds for Unpatentability

Ground 1: Claims 1-3 are anticipated by Chern under 35 U.S.C. §102

  • Prior Art Relied Upon: Chern (Patent 5,126,590).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Chern discloses every limitation of claims 1-3. Chern describes a high-efficiency charge pump that, like the ’875 patent, addresses the well-known problem of output voltage ripple by arranging two boosting circuits in parallel that operate out of phase.
      • Claim 1 (Boost Circuit): Petitioner mapped the elements of claim 1 to Chern's Figure 2. It contended that Chern’s transistors Q1 and Q2 function as the claimed first and second switches, coupled between the input terminal (22) and output terminal (24). These switches are operated by clock signals φ4 and φ3, respectively, which Chern’s timing diagrams show are opposite phase signals. Further, Chern’s capacitors C1 and C2 were identified as the claimed first and second capacitors, each coupled to the output terminal and receiving a boost signal (clock signals φ1 and φ2, respectively).
      • Claim 2 (Buffers): Petitioner asserted that Chern’s four-phase clock generator (42) discloses the claimed inverting and non-inverting buffers. The petition argued that the top half of the generator circuit functions as an inverting buffer that receives a boost signal and provides an inverted output (clock φ1) to the first capacitor. The bottom half of the generator was argued to be a non-inverting buffer providing a non-inverted output (clock φ2) to the second capacitor.
      • Claim 3 (Third/Fourth Switches): Petitioner mapped the additional switches of claim 3 to Chern's transistors Q5 and Q6. Transistor Q5 was identified as the "third switch" coupled between the first capacitor (C1) and the output terminal, operated by the second phase signal (φ3). Transistor Q6 was identified as the "fourth switch" coupled between the second capacitor (C2) and the output, operated by the first phase signal (φ4).

Ground 2: Claims 1-3 are obvious over Chern under 35 U.S.C. §103

  • Prior Art Relied Upon: Chern (Patent 5,126,590).
  • Core Argument for this Ground:
    • Prior Art Mapping: As an alternative to its anticipation argument, Petitioner contended that claims 1-3 are obvious over Chern. The petition asserted that because anticipation is the "epitome of obviousness," a reference that anticipates also renders a claim obvious. To the extent any minor differences between Chern and the claims could be identified, Petitioner argued that bridging them would have been obvious to a person of ordinary skill in the art (POSITA).
    • Motivation to Combine: The motivation to modify Chern, if any modification were needed, stemmed from the shared objective of solving the known problem of voltage ripple in charge pumps. Chern explicitly teaches using two out-of-phase boosting circuits in parallel to create a more stable output. A POSITA implementing Chern’s design would be motivated to use standard and predictable circuit elements to realize this functionality. For example, generating the required complementary clock signals would have obviously led a POSITA to employ basic inverting and non-inverting logic gates or buffers, as claimed in claim 2.
    • Expectation of Success: A POSITA would have had a high expectation of success in implementing the claimed invention based on Chern’s teachings. The design involves the predictable application of fundamental circuit components—including transistors as switches, capacitors for charge storage, and logic gates for signal generation—all operating according to their well-understood principles to achieve a predictable result.

4. Key Claim Construction Positions

  • "Coupled": Petitioner dedicated a section to construing the term "coupled," which appears in all challenged claims.
    • Petitioner proposed the construction: "directly or indirectly connecting, such as through intervening circuit elements."
    • The argument was based on intrinsic evidence from the ’875 patent itself. Petitioner pointed to Figure 3 of the patent, which illustrates embodiments where other components (e.g., another switch) are located between the elements recited as being "coupled." A construction limited to direct connection would, therefore, improperly exclude embodiments disclosed in the specification, which is strongly disfavored under claim construction principles.

5. Relief Requested

  • Petitioner requested the institution of an inter partes review and the cancellation of claims 1-3 of Patent 6,127,875 as unpatentable under 35 U.S.C. §§ 102 and 103.