Patents by Inventor Akihiko Kanda

Akihiko Kanda 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: 7894251
    Abstract: The present invention provides a semiconductor memory device capable of preventing erroneous writing of a data signal. In DL drivers of an MRAM, transistors corresponding to a selected digit line group are made conductive to charge 16 digit lines to power supply voltage and charge a node to a predetermined voltage VP1=VDD?VTH1. After that, a transistor corresponding to the selected digit line is made conductive to make magnetization current flow. Therefore, occurrence of overshooting of magnetization current when the transistor is made conductive can be prevented.
    Type: Grant
    Filed: May 6, 2009
    Date of Patent: February 22, 2011
    Assignee: Renesas Electronics Corporation
    Inventor: Akihiko Kanda
  • Patent number: 7742334
    Abstract: A memory cell of a memory array stores two bits. A memory array sense amplifier provides two bits in a verify operation. Two bits in a page buffer stores a write target value for the corresponding memory cell. Each bit in a mask buffer stores a value defining processing to be effected on the corresponding memory cell. A write driver applies a write pulse when the bit in the mask buffer corresponding to the selected memory cell is “0”. A verify circuit compares the two bits provided from the memory array sense amplifier with the corresponding two bits in the page buffer, and changes the corresponding bit in the mask buffer from “0” to “1” when the result of the comparison represents matching.
    Type: Grant
    Filed: June 25, 2007
    Date of Patent: June 22, 2010
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Tomoyuki Fujisawa, Hikaru Shibahara, Hidenori Mitani, Akihiko Kanda
  • Publication number: 20090296460
    Abstract: The present invention provides a semiconductor memory device capable of preventing erroneous writing of a data signal. In DL drivers of an MRAM, transistors corresponding to a selected digit line group are made conductive to charge 16 digit lines to power supply voltage and charge a node to a predetermined voltage VP1=VDD?VTH1. After that, a transistor corresponding to the selected digit line is made conductive to make magnetization current flow. Therefore, occurrence of overshooting of magnetization current when the transistor is made conductive can be prevented.
    Type: Application
    Filed: May 6, 2009
    Publication date: December 3, 2009
    Inventor: Akihiko KANDA
  • Publication number: 20090129149
    Abstract: A memory cell of a memory array stores two bits. A memory array sense amplifier provides two bits in a verify operation. Two bits in a page buffer stores a write target value for the corresponding memory cell. Each bit in a mask buffer stores a value defining processing to be effected on the corresponding memory cell. A write driver applies a write pulse when the bit in the mask buffer corresponding to the selected memory cell is “0”. A verify circuit compares the two bits provided from the memory array sense amplifier with the corresponding two bits in the page buffer, and changes the corresponding bit in the mask buffer from “0” to “1” when the result of the comparison represents matching.
    Type: Application
    Filed: June 25, 2007
    Publication date: May 21, 2009
    Inventors: Tomoyuki Fujisawa, Hikaru Shibahara, Hidenori Mitani, Akihiko Kanda
  • Patent number: 7518929
    Abstract: A memory cell of a memory array stores two bits. A memory array sense amplifier provides two bits in a verify operation. Two bits in a page buffer stores a write target value for the corresponding memory cell. Each bit in a mask buffer stores a value defining processing to be effected on the corresponding memory cell. A write driver applies a write pulse when the bit in the mask buffer corresponding to the selected memory cell is “0”. A verify circuit compares the two bits provided from the memory array sense amplifier with the corresponding two bits in the page buffer, and changes the corresponding bit in the mask buffer from “0” to “1” when the result of the comparison represents matching.
    Type: Grant
    Filed: June 25, 2007
    Date of Patent: April 14, 2009
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Tomoyuki Fujisawa, Hikaru Shibahara, Hidenori Mitani, Akihiko Kanda
  • Publication number: 20080019176
    Abstract: A memory cell of a memory array stores two bits. A memory array sense amplifier provides two bits in a verify operation. Two bits in a page buffer stores a write target value for the corresponding memory cell. Each bit in a mask buffer stores a value defining processing to be effected on the corresponding memory cell. A write driver applies a write pulse when the bit in the mask buffer corresponding to the selected memory cell is “0”. A verify circuit compares the two bits provided from the memory array sense amplifier with the corresponding two bits in the page buffer, and changes the corresponding bit in the mask buffer from “0” to “1” when the result of the comparison represents matching.
    Type: Application
    Filed: June 25, 2007
    Publication date: January 24, 2008
    Applicant: Renesas Technology Corp.
    Inventors: Tomoyuki Fujisawa, Hikaru Shibahara, Hidenori Mitani, Akihiko Kanda
  • Patent number: 7242611
    Abstract: A memory cell of a memory array stores two bits. A memory array sense amplifier provides two bits in a verify operation. Two bits in a page buffer stores a write target value for the corresponding memory cell. Each bit in a mask buffer stores a value defining processing to be effected on the corresponding memory cell. A write driver applies a write pulse when the bit in the mask buffer corresponding to the selected memory cell is “0”. A verify circuit compares the two bits provided from the memory array sense amplifier with the corresponding two bits in the page buffer, and changes the corresponding bit in the mask buffer from “0” to “1” when the result of the comparison represents matching.
    Type: Grant
    Filed: March 18, 2005
    Date of Patent: July 10, 2007
    Assignee: Renesas Technology Corp.
    Inventors: Tomoyuki Fujisawa, Hikaru Shibahara, Hidenori Mitani, Akihiko Kanda
  • Publication number: 20070036001
    Abstract: After data writing is performed by injecting electrons into a floating gate from a semiconductor substrate of a memory cell, the gate voltage is set at ?3 V, and the source voltage, the drain voltage and the substrate voltage are set at 0 V, thereby detrapping the electrons trapped in an oxide film during data writing. The gate voltage (?3 V) is set at a negative voltage value that is smaller in absolute value than the gate voltage (?10.5 V) applied during data erasing.
    Type: Application
    Filed: July 27, 2006
    Publication date: February 15, 2007
    Inventors: Akihiko Kanda, Taku Ogura, Makoto Muneyasu
  • Publication number: 20050232017
    Abstract: A memory cell of a memory array stores two bits. A memory array sense amplifier provides two bits in a verify operation. Two bits in a page buffer stores a write target value for the corresponding memory cell. Each bit in a mask buffer stores a value defining processing to be effected on the corresponding memory cell. A write driver applies a write pulse when the bit in the mask buffer corresponding to the selected memory cell is “0”. A verify circuit compares the two bits provided from the memory array sense amplifier with the corresponding two bits in the page buffer, and changes the corresponding bit in the mask buffer from “0” to “1” when the result of the comparison represents matching.
    Type: Application
    Filed: March 18, 2005
    Publication date: October 20, 2005
    Inventors: Tomoyuki Fujisawa, Hikaru Shibahara, Hidenori Mitani, Akihiko Kanda