PTAB

IPR2018-01154

Intel Corp v. Qualcomm Inc

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Techniques for Efficiently Generating a Power Supply for a Power Amplifier
  • Brief Description: The ’558 patent discloses an apparatus for generating a power supply signal for a radio frequency (RF) power amplifier. The invention combines a high-efficiency switcher with a high-bandwidth envelope amplifier and purports to improve overall efficiency by selectively using a boost converter and adding an offset current to the switcher's input to reallocate the power load.

3. Grounds for Unpatentability

Ground I: Anticipation of Claims 15, 17-18, and 20 under 35 U.S.C. §102 over Kwak

  • Prior Art Relied Upon: Kwak (a 2007 IEEE paper, “A 2 W CMOS hybrid switching amplitude modulator for EDGE polar transmitters”).
  • Core Argument for this Ground: Petitioner asserted that Kwak, a reference not considered during the original prosecution, discloses every element of independent claim 15 and its dependent claims 17, 18, and 20. The features that the Examiner previously found to be missing from the prior art of record are allegedly present in Kwak.
    • Prior Art Mapping: Petitioner argued that Kwak’s hybrid switching amplifier apparatus anticipates claim 15. Kwak’s switcher was shown to sense an input current, add an offset current via a “feedforward path” and a summing circuit (Σ), and generate a switching signal for an inductor. This process generates a larger supply current than it would without the offset, directly mapping to the core limitations of claim 15. For the dependent claims, Petitioner contended that Kwak also disclosed the specific P-channel metal oxide semiconductor (PMOS) and N-channel metal oxide semiconductor (NMOS) transistor configurations for the switcher (claim 17), the combination with a wideband linear envelope amplifier providing a second supply current (claim 18), and the explicit use of the entire apparatus to drive a power amplifier (claim 20).

Ground II: Obviousness of Claim 16 under 35 U.S.C. §103 over Kwak

  • Prior Art Relied Upon: Kwak (a 2007 IEEE paper).
  • Core Argument for this Ground: Claim 16 depends from claim 15 and adds the limitations that the switcher operates based on a first supply voltage and that the offset is determined based on that same voltage.
    • Prior Art Mapping: Petitioner argued that Kwak’s switcher clearly operates using the primary supply voltage (Vdd). The offset current is provided by Kwak’s “AF block,” which is depicted with a triangle symbol suggesting an amplifier.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would find it obvious to implement the AF block with a standard active amplifier component to provide the necessary gain for the feedforward path. The most obvious and logical choice for powering this amplifier would be the readily available supply voltage (Vdd).
    • Expectation of Success: The performance and output current of any such amplifier are inherently dependent on its supply voltage. Therefore, a POSITA would have immediately understood that the offset current generated by the AF block would be determined by Vdd, making the claimed subject matter an obvious design choice with a high expectation of success.

Ground III: Obviousness of Claim 19 under 35 U.S.C. §103 over Kwak in view of Choi 2010

  • Prior Art Relied Upon: Kwak (a 2007 IEEE paper) and Choi 2010 (a 2010 IEEE paper, “Envelope tracking power amplifier robust to battery depletion”).
  • Core Argument for this Ground: Claim 19, which depends from claim 18, adds a boost converter to the apparatus. While Kwak provides the base circuit with the offset current, Choi 2010 explicitly teaches the benefits of adding a boost converter to a nearly identical hybrid amplifier architecture.
    • Prior Art Mapping: Kwak was asserted to disclose the base apparatus of claim 18. Choi 2010 was shown to disclose a hybrid supply modulator that incorporates a boost converter (termed a "Regulator") coupled to the linear amplifier supply. The explicit purpose of this boost converter was to maintain a stable supply voltage and prevent performance degradation as the battery depletes.
    • Motivation to Combine: A POSITA would be motivated to combine the teachings to improve Kwak’s design. Both references are from the same technical field, address supply modulators for PAs, and Choi 2010 even cites Kwak as background art. The motivation would be to solve the well-known problem of distortion and performance loss from a depleting battery by incorporating Choi's boost converter—a solution explicitly taught by Choi 2010 to provide robust performance.
    • Expectation of Success: The proposed combination was a predictable application of a known technique (boosting a supply voltage) to a similar device (Kwak's amplifier) to achieve a well-understood benefit (stable operation despite battery voltage drop). Petitioner argued this amounted to a simple substitution of a standard power supply for a boosted one, which would yield entirely predictable results.

4. Key Claim Construction Positions

  • Petitioner adopted claim constructions from a parallel International Trade Commission (ITC) litigation, arguing they were either correct or favorable to the Patent Owner.
  • "current sense amplifier" (claim 15): Construed as an "amplifier that produces a voltage from a current." Petitioner asserted this construction is consistent with the specification and allows the combination of Kwak's integrator and comparator circuits to meet the claim limitation.
  • "envelope signal" (claim 18): Construed as a "signal indicative of the upper bound of the output RF signal." Petitioner adopted this construction, which was originally proposed by the Patent Owner in the parallel litigation.

5. Relief Requested

  • Petitioner requests institution of inter partes review and cancellation of claims 15-20 of Patent 8,698,558 as unpatentable.