PTAB

IPR2020-00383

Nuvoton Technology Corp v. Microchip Technology Inc

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Selectable Real Time Sample Triggering for a Plurality of Inputs of An Analog-to-Digital Converter
  • Brief Description: The ’515 patent describes an analog-to-digital (A/D) conversion apparatus that uses a plurality of sample and hold (S/H) circuits and corresponding trigger selection circuits. The system is designed to selectively couple multiple analog inputs to their respective S/H circuits based on various trigger signals, and then route the sampled values to one or more A/D converters.

3. Grounds for Unpatentability

Ground 1: Claims 1, 5, 7, 9-11, 13, and 14 are obvious over Campbell in view of Caruba.

  • Prior Art Relied Upon: Campbell (Patent 5,081,454) and Caruba (Patent 8,076,646).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Campbell, the primary reference, disclosed a flexible A/D converter system that met most limitations of the challenged claims. Campbell taught a system with multiple analog inputs, two S/H circuits, an A/D converter, an analog multiplexer, and a "Trigger Select & Priority Circuit." However, Petitioner asserted that Campbell’s single trigger circuit only allowed for simultaneous sampling. Caruba was introduced to teach a system with a plurality of S/H circuits, each having its own independent trigger circuit. Petitioner contended that Caruba’s teaching of independent triggers for each S/H circuit rendered the ’515 patent’s claimed "plurality of trigger selection circuits" obvious.
    • Motivation to Combine: A POSITA would combine Caruba's concept of independent trigger circuits with Campbell's more sophisticated A/D system to improve efficiency and performance. This combination would enable the Campbell system to handle both "frequently occurring or time-critical" and "non-time-critical" conversion sequences more effectively by allowing for immediate, independent capture of values from different analog inputs, which Campbell's simultaneous sampling could not do. The motivation was to apply a known technique (independent triggering from Caruba) to improve a known system (Campbell).
    • Expectation of Success: Petitioner asserted a POSITA would have a high expectation of success because the modification involved applying a known technique to achieve individual control of Campbell’s S/H circuits. The design would require minimal redesign, as the existing priority circuitry in Campbell could be used to coordinate the multiple, independent trigger selection circuits.

Ground 2: Claims 10, 11, 13, and 14 are obvious over Campbell, Caruba, and PWM Introduction.

  • Prior Art Relied Upon: Campbell (’454 patent), Caruba (’646 patent), and PWM Introduction ("Introduction to Pulse Width Modulation (PWM)," Barr Group (Sep. 2001)).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground specifically addressed the preamble of independent claim 10, which recites a "pulse width modulation (PWM) control system." While arguing the preamble was not limiting, Petitioner presented this ground in the alternative. The core teachings of Campbell and Caruba were incorporated from Ground 1. The PWM Introduction was added to explicitly teach that controlling PWM systems digitally was a common and advantageous application for A/D converters and that many microcontrollers already included on-chip PWM controllers.
    • Motivation to Combine: A POSITA would be motivated to apply the flexible and efficient A/D conversion system of the Campbell-Caruba combination to the known field of PWM control. The PWM Introduction established that such digital control was a routine application. Therefore, providing the precision and flexibility of the proposed Campbell-Caruba system for PWM control would have been an obvious improvement.
    • Expectation of Success: Success was expected because replacing a generic PWM controller with the more flexible Campbell-Caruba system would have been a routine task for a POSITA. The PWM Introduction noted that while specific PWM controllers vary, the basic idea is generally the same.

Ground 3: Claims 1, 2, 5, 7, 9-11, 13, and 14 are obvious over Campbell, Caruba, and the ATmega16 Datasheet.

  • Prior Art Relied Upon: Campbell (’454 patent), Caruba (’646 patent), and the ATmega16 Datasheet (Datasheet for Atmel ATmega16/16L Microcontrollers, 2003).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground built upon the Campbell-Caruba combination by introducing the ATmega16 Datasheet to provide a specific, well-known implementation for the "trigger selection circuit" of claim 2. Petitioner argued that Campbell’s disclosure of its "Trigger Select & Priority Circuit" was only a high-level functional block. The ATmega16 Datasheet disclosed detailed auto-trigger logic, including a trigger multiplexer and an edge detector, that was "virtually the same" as the circuit shown in the ’515 patent. This reference provided the concrete circuitry needed to implement Campbell's functional block.
    • Motivation to Combine: A POSITA seeking to implement the functional trigger circuit described in Campbell would have been motivated to look to well-known, commercially available datasheets for a specific circuit design. The ATmega16 Datasheet provided a suitable, off-the-shelf design with a similar architecture. A POSITA would use multiple instances of this trigger logic—one for each S/H circuit, as taught by the combination with Caruba—to allow the circuits to operate independently and trigger off an edge, which is more precise than Caruba's threshold trigger.
    • Expectation of Success: A POSITA would have a reasonable expectation of success because the ATmega16 Datasheet disclosed a "successful, but simple, specific trigger selection circuit" that fit logically into the Campbell-Caruba system. This involved the "mere application of a known technique to a piece of prior art ready for the improvement."

4. Relief Requested

  • Petitioner requested the institution of an inter partes review and the cancellation of claims 1, 2, 5, 7, 9-11, 13, and 14 of the ’515 patent as unpatentable.