Patents by Inventor Mitsuharu Sakakibara

Mitsuharu Sakakibara 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: 9042182
    Abstract: A nonvolatile semiconductor memory device includes a memory cell array, a plurality of local sense amplifiers, a global sense amplifier and an address decoder. The address decoder is configured to switch between a first verification and a second verification. The first verification operates the plurality of local sense amplifiers and simultaneously verifies data of a plurality of memory cells connected to the plurality of local sense amplifiers. The second verification stops the plurality of local sense amplifiers, directly connects the local bit line connected to each of the local sense amplifiers with the global bit line, and simultaneously verifies data of the plurality of memory cells connected to the plurality of local sense amplifiers.
    Type: Grant
    Filed: October 26, 2012
    Date of Patent: May 26, 2015
    Assignee: FUJITSU SEMICONDUCTOR LIMITED
    Inventor: Mitsuharu Sakakibara
  • Patent number: 7359251
    Abstract: A non-volatile semiconductor memory device includes a memory cell array and an operation control circuit. The memory cell array includes a plurality of non-volatile memory cells that are electrically rewritable. The operation control circuit controls an operation of the memory cell array in accordance with an external instruction. The operation control circuit includes a flag circuit and an erase prohibition circuit. The flag circuit is set when erase incompletion is detected from any of the memory cells by an erase verify operation of the memory cell array. The erase prohibition circuit prohibits an erase operation to the memory cell array irrespective of the external instruction when the flag circuit is in a reset state.
    Type: Grant
    Filed: September 11, 2006
    Date of Patent: April 15, 2008
    Assignee: Fujitsu Limited
    Inventors: Junko Okawara, Mitsuharu Sakakibara, Naoto Emi, Tomoharu Sohma
  • Patent number: 7149136
    Abstract: A memory circuit has a regular memory cell array; a redundant memory cell array that can replace a failed portion in the regular memory cell array; a redundant replacement memory for storing data on the failed portion in the regular memory cell array; and a pre-charge circuit disposed in the regular memory cell array, depending on the data on the failed portion, the failed portion in the regular memory cell array is replaced with the redundant memory cell array, whilst a pre-charge path is closed which leads to the pre-charge circuit corresponding to the failed portion. This enables a common redundant replacement memory to effect a relief of the failed portion and shutoff of the pre-charge current to the failed portion.
    Type: Grant
    Filed: December 1, 2005
    Date of Patent: December 12, 2006
    Assignee: Fujitsu Limited
    Inventors: Motoko Tanishima, Mitsuharu Sakakibara
  • Publication number: 20060083086
    Abstract: A memory circuit has a regular memory cell array; a redundant memory cell array that can replace a failed portion in the regular memory cell array; a redundant replacement memory for storing data on the failed portion in the regular memory cell array; and a pre-charge circuit disposed in the regular memory cell array, depending on the data on the failed portion, the failed portion in the regular memory cell array is replaced with the redundant memory cell array, whilst a pre-charge path is closed which leads to the pre-charge circuit corresponding to the failed portion. This enables a common redundant replacement memory to effect a relief of the failed portion and shutoff of the pre-charge current to the failed portion.
    Type: Application
    Filed: December 1, 2005
    Publication date: April 20, 2006
    Inventors: Motoko Tanishima, Mitsuharu Sakakibara
  • Patent number: 6999357
    Abstract: A memory circuit has a regular memory cell array; a redundant memory cell array that can replace a failed portion in the regular memory cell array; a redundant replacement memory for storing data on the failed portion in the regular memory cell array; and a pre-charge circuit disposed in the regular memory cell array, depending on the data on the failed portion, the failed portion in the regular memory cell array is replaced with the redundant memory cell array, whilst a pre-charge path is closed which leads to the pre-charge circuit corresponding to the failed portion. This enables a common redundant replacement memory to effect a relief of the failed portion and shutoff of the pre-charge current to the failed portion.
    Type: Grant
    Filed: August 5, 2003
    Date of Patent: February 14, 2006
    Assignee: Fujitsu Limited
    Inventors: Motoko Tanishima, Mitsuharu Sakakibara
  • Publication number: 20040027880
    Abstract: A memory circuit has a regular memory cell array; a redundant memory cell array that can replace a failed portion in the regular memory cell array; a redundant replacement memory for storing data on the failed portion in the regular memory cell array; and a pre-charge circuit disposed in the regular memory cell array, depending on the data on the failed portion, the failed portion in the regular memory cell array is replaced with the redundant memory cell array, whilst a pre-charge path is closed which leads to the pre-charge circuit corresponding to the failed portion. This enables a common redundant replacement memory to effect a relief of the failed portion and shutoff of the pre-charge current to the failed portion.
    Type: Application
    Filed: August 5, 2003
    Publication date: February 12, 2004
    Applicant: FUJITSU LIMITED
    Inventors: Motoko Tanishima, Mitsuharu Sakakibara