Patents by Inventor Takafumi Nakashiba

Takafumi Nakashiba has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 7295938
    Abstract: In a voltage drop analysis step S101, the process calculates a temporal variation of a power source voltage supplied to each cell along a transmission path of a clock signal. In a delay variation rate ratio calculation step S102, the process calculates a delay time variation of each cell according to the power source voltage variation. In a clock delay variation amount calculation step S103, the process obtains the magnitude of jitter of the clock signal based on the delay time variation.
    Type: Grant
    Filed: March 30, 2006
    Date of Patent: November 13, 2007
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Takafumi Nakashiba, Takahiro Ochi, Mitsuko Takada
  • Patent number: 7249334
    Abstract: In hierarchical design of a logic circuit by utilizing lower-level blocks of the logic circuit, data on the logic circuit with the hierarchical structure, library data holding primitive information on the logic circuit and timing constraints on the lower-level blocks are input at a data input step. Based on these input data, it is determined whether or not interface specifications of timing constraints on the lower-level blocks match each other at a matching determination step before a constraint converting step of converting the timing constraints on the lower-level blocks into a timing constraint on a higher-level block. Accordingly, it is possible to avoid generation of an excessively reduced or rigorous timing constraint on the higher-level block resulting from mismatching between interface specifications of timing constraints on the lower-level blocks.
    Type: Grant
    Filed: May 4, 2005
    Date of Patent: July 24, 2007
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventor: Takafumi Nakashiba
  • Publication number: 20060220751
    Abstract: In a voltage drop analysis step S101, the process calculates a temporal variation of a power source voltage supplied to each cell along a transmission path of a clock signal. In a delay variation rate ratio calculation step S102, the process calculates a delay time variation of each cell according to the power source voltage variation. In a clock delay variation amount calculation step S103, the process obtains the magnitude of jitter of the clock signal based on the delay time variation.
    Type: Application
    Filed: March 30, 2006
    Publication date: October 5, 2006
    Inventors: Takafumi Nakashiba, Takahiro Ochi, Mitsuko Takada
  • Publication number: 20050251780
    Abstract: In hierarchical design of a logic circuit by utilizing lower-level blocks of the logic circuit, data on the logic circuit with the hierarchical structure, library data holding primitive information on the logic circuit and timing constraints on the lower-level blocks are input at a data input step. Based on these input data, it is determined whether or not interface specifications of timing constraints on the lower-level blocks match each other at a matching determination step before a constraint converting step of converting the timing constraints on the lower-level blocks into a timing constraint on a higher-level block. Accordingly, it is possible to avoid generation of an excessively reduced or rigorous timing constraint on the higher-level block resulting from mismatching between interface specifications of timing constraints on the lower-level blocks.
    Type: Application
    Filed: May 4, 2005
    Publication date: November 10, 2005
    Inventor: Takafumi Nakashiba