Patents by Inventor Yuki Ushida

Yuki Ushida 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).

  • Decoder checking circuits suitable for semiconductor memories
    Patent number: 5331644
    Abstract: A decoder checking circuit for testing a decoder in a semiconductor memory device, comprising an address signal generator for generating a test address signal, a first switch for transferring selectively either the address signal or the test address signal, to a decoder, a second switch for transferring the output of the decoder to the memory cell array, an expected value generator for generating an expected value for the output of the decoder, and a comparing circuit for comparing the output of the second switch with the expected value.
    Type: Grant
    Filed: July 10, 1991
    Date of Patent: July 19, 1994
    Assignee: Oki Electric Industry Co., Ltd.
    Inventors: Satoshi Ishii, Yuki Ushida
  • Semiconductor memory device
    Patent number: 4984215
    Abstract: In a semiconductor memory device comprising a memory cell matrix having memory cells connected to word lines and bit lines and arranged in rows and columns, an initialize circuit is responsive to an initialize signal to set all the bit lines to predefined one of High level and Low level, and to raise the word line selected by the output of a row address decoder and then to raise other word lines sequentially. As a result, the memory cells are initialized sequentially word line by word line.
    Type: Grant
    Filed: June 29, 1989
    Date of Patent: January 8, 1991
    Assignee: Oki Electric Industry Co., Inc.
    Inventor: Yuki Ushida