PTAB

IPR2015-01135

NVIDIA Corp v. Samsung Electronics Co Ltd

Log In
Key Events
Petition
petition Intelligence

1. Case Identification

2. Patent Overview

  • Title: Data Strobe Buffer and Memory System Including the Same
  • Brief Description: The ’734 patent discloses a data strobe buffer for semiconductor memory systems. The buffer is designed to interface with different types of memory devices by supporting multiple signaling schemes, such as single-ended signaling (used in DDR memory) and differential signaling (used in DDR2 memory), within a single memory controller.

3. Grounds for Unpatentability

Ground 1: Obviousness over Seo in view of Kong - Claims 1, 7-9, 12, 13, 17, and 19 are obvious over Seo in view of Kong.

  • Prior Art Relied Upon: Seo (Patent 6,819,602) and Kong (Patent 7,173,871).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Seo teaches the core invention of a multi-mode data strobe buffer capable of handling both single-ended and differential data strobe signals. Seo discloses a receiver circuit with a selector (switches) and a comparator (differential amplifier) that chooses between comparing an incoming data strobe signal to either a reference voltage (single-ended mode) or its inverse signal (differential mode). While Seo provides the key receiver functionality, it lacks a detailed disclosure of the driver circuitry for outputting a data strobe signal. Petitioner asserted that Kong remedies this deficiency by teaching the detailed internal configuration of a bi-directional data strobe signal driver, including a tri-state buffer, capable of driving a data strobe signal through an input/output node. The combination of Seo's versatile multi-mode receiver with Kong's explicit driver circuit allegedly discloses all limitations of the challenged claims.
    • Motivation to Combine: Petitioner presented several motivations for a person of ordinary skill in the art (POSITA) to combine the teachings of Seo and Kong. The primary motivations were:
      • Common Origin and Technology: Both Seo and Kong were assigned to the same entity (Samsung), relate to the same DDR memory technology, and were developed by Samsung employees in Korea at roughly the same time. A POSITA at Samsung would have presumptively known of both works and been motivated to combine them for design efficiency.
      • Complementary Disclosures: The references solve different aspects of the same problem. Seo focuses on a multi-mode receiver, while Kong details a compatible driver for the same type of bi-directional buffer. A POSITA seeking to build a complete input/output buffer would have naturally looked to Kong to supply the driver details missing from Seo.
      • Explicit Cross-Citation: The Kong patent explicitly cites the Seo patent on its face, providing a direct link and motivation for a POSITA to consider their teachings together.
    • Expectation of Success: Petitioner argued that a POSITA would have had a high expectation of success because the references are not incompatible. Combining Kong's standard driver circuit with Seo's receiver circuit was presented as a straightforward integration of known, complementary components to achieve the predictable result of a fully functional, multi-mode, bi-directional data strobe buffer.

4. Key Claim Construction Positions

  • "input/output node": Petitioner argued for a construction of "a point in a circuit through which signals may be input and/or output." This construction was asserted to be consistent with the specification and also aligned with a construction proposed by the Patent Owner in a related litigation, making it central to mapping the I/O pads in the prior art to the claimed nodes.
  • "coupled": Petitioner proposed construing this term as "connected either directly or through intervening elements." This broad interpretation was important for establishing the required connections between the various drivers, receivers, selectors, and nodes taught across the combined prior art references.

5. Key Technical Contentions (Beyond Claim Construction)

  • Perspective of the Disclosure: A central technical argument was that the location of the data strobe buffer does not alter the invalidity analysis. Petitioner contended that while the ’734 patent describes the buffer from the perspective of the memory controller, and Seo and Kong describe it from the perspective of the memory device (DRAM), the underlying circuit components and their functions are identical and symmetrical. It was argued that a POSITA would understand that the bi-directional nature of the buffer means the same circuit design is used in both the controller and the device, rendering the differing perspectives irrelevant to the technical teachings.

6. Arguments Regarding Discretionary Denial

  • No Redundancy with Prior Petition: The petition was filed as "'734 Petition #2," acknowledging a previously filed petition ("'734 Petition #1"). Petitioner argued against discretionary denial by asserting this petition was not redundant or duplicative because it relied on entirely different prior art and grounds. The first petition was based primarily on an anticipation theory using a third-party patent (Lai), whereas this petition focused exclusively on an obviousness combination of the Patent Owner's own prior art (Seo and Kong).

7. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claims 1, 7-9, 12, 13, 17, and 19 of the ’734 patent as unpatentable.