Patents by Inventor Tadashi Yasufuku

Tadashi Yasufuku 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: 10672487
    Abstract: A semiconductor memory device includes first and second memory cells, each of which includes a charge storage layer, a first bit line that is connected to the first memory cell, and a second bit line that is connected to the second memory cell. A writing operation includes multiple loops of a programming operation and a verification operation, and first data is written in the first memory cell, and second data different from the first data is written in the second memory cell through the writing operation. In a first loop of the writing operation, a first voltage is applied to the first bit line and the second bit line is maintained in an electrically floating state during the programming operation, and a verification operation relating to the second data is not performed and a verification operation relating to the first data is performed.
    Type: Grant
    Filed: July 1, 2019
    Date of Patent: June 2, 2020
    Assignee: Toshiba Memory Corporation
    Inventors: Hiroshi Maejima, Koji Hosono, Tadashi Yasufuku, Noboru Shibata
  • Patent number: 10553283
    Abstract: According to one embodiment, a semiconductor storage device includes a first plane having a first plurality of memory cells, a second plane having a second plurality of memory cells, first bit lines which are connected to the first plane, second bit lines which are connected to the second plane, a plurality of first sense amplifiers which charge the plurality of first bit lines, and a plurality of second sense amplifiers which charge the plurality of second bit lines. When the first and second planes operate in parallel, a total sum of currents supplied to the plurality of first bit lines from the plurality of first sense amplifiers and currents supplied to the plurality of second bit lines from the plurality of second sense amplifiers reaches a first current value, then decreases to a second current value, and then increases to a third current value.
    Type: Grant
    Filed: August 29, 2018
    Date of Patent: February 4, 2020
    Assignee: TOSHIBA MEMORY CORPORATION
    Inventors: Yoko Deguchi, Kosuke Yanagidaira, Tadashi Yasufuku, Takuyo Kodama
  • Publication number: 20190355421
    Abstract: According to one embodiment, a semiconductor storage device includes a first plane having a first plurality of memory cells, a second plane having a second plurality of memory cells, first bit lines which are connected to the first plane, second bit lines which are connected to the second plane, a plurality of first sense amplifiers which charge the plurality of first bit lines, and a plurality of second sense amplifiers which charge the plurality of second bit lines. When the first and second planes operate in parallel, a total sum of currents supplied to the plurality of first bit lines from the plurality of first sense amplifiers and currents supplied to the plurality of second bit lines from the plurality of second sense amplifiers reaches a first current value, then decreases to a second current value, and then increases to a third current value.
    Type: Application
    Filed: August 29, 2018
    Publication date: November 21, 2019
    Inventors: Yoko DEGUCHI, Kosuke YANAGIDAIRA, Tadashi YASUFUKU, Takuyo KODAMA
  • Publication number: 20190325973
    Abstract: A semiconductor memory device includes first and second memory cells, each of which includes a charge storage layer, a first bit line that is connected to the first memory cell, and a second bit line that is connected to the second memory cell. A writing operation includes multiple loops of a programming operation and a verification operation, and first data is written in the first memory cell, and second data different from the first data is written in the second memory cell through the writing operation. In a first loop of the writing operation, a first voltage is applied to the first bit line and the second bit line is maintained in an electrically floating state during the programming operation, and a verification operation relating to the second data is not performed and a verification operation relating to the first data is performed.
    Type: Application
    Filed: July 1, 2019
    Publication date: October 24, 2019
    Inventors: Hiroshi MAEJIMA, Koji HOSONO, Tadashi YASUFUKU, Noboru SHIBATA
  • Patent number: 10381096
    Abstract: A semiconductor memory device includes first and second memory cells, each of which includes a charge storage layer, a first bit line that is connected to the first memory cell, and a second bit line that is connected to the second memory cell. A writing operation includes multiple loops of a programming operation and a verification operation, and first data is written in the first memory cell, and second data different from the first data is written in the second memory cell through the writing operation. In a first loop of the writing operation, a first voltage is applied to the first bit line and the second bit line is maintained in an electrically floating state during the programming operation, and a verification operation relating to the second data is not performed and a verification operation relating to the first data is performed.
    Type: Grant
    Filed: May 23, 2018
    Date of Patent: August 13, 2019
    Assignee: Toshiba Memory Corporation
    Inventors: Hiroshi Maejima, Koji Hosono, Tadashi Yasufuku, Noboru Shibata
  • Publication number: 20180301197
    Abstract: A semiconductor memory device includes first and second memory cells, each of which includes a charge storage layer, a first bit line that is connected to the first memory cell, and a second bit line that is connected to the second memory cell. A writing operation includes multiple loops of a programming operation and a verification operation, and first data is written in the first memory cell, and second data different from the first data is written in the second memory cell through the writing operation. In a first loop of the writing operation, a first voltage is applied to the first bit line and the second bit line is maintained in an electrically floating state during the programming operation, and a verification operation relating to the second data is not performed and a verification operation relating to the first data is performed.
    Type: Application
    Filed: May 23, 2018
    Publication date: October 18, 2018
    Inventors: Hiroshi MAEJIMA, Koji HOSONO, Tadashi YASUFUKU, Noboru SHIBATA
  • Patent number: 9984761
    Abstract: A semiconductor memory device includes first and second memory cells, each of which includes a charge storage layer, a first bit line that is connected to the first memory cell, and a second bit line that is connected to the second memory cell. A writing operation includes multiple loops of a programming operation and a verification operation, and first data is written in the first memory cell, and second data different from the first data is written in the second memory cell through the writing operation. In a first loop of the writing operation, a first voltage is applied to the first bit line and the second bit line is maintained in an electrically floating state during the programming operation, and a verification operation relating to the second data is not performed and a verification operation relating to the first data is performed.
    Type: Grant
    Filed: August 10, 2016
    Date of Patent: May 29, 2018
    Assignee: Toshiba Memory Corporation
    Inventors: Hiroshi Maejima, Koji Hosono, Tadashi Yasufuku, Noboru Shibata
  • Publication number: 20170178739
    Abstract: A semiconductor memory device includes first and second memory cells, each of which includes a charge storage layer, a first bit line that is connected to the first memory cell, and a second bit line that is connected to the second memory cell. A writing operation includes multiple loops of a programming operation and a verification operation, and first data is written in the first memory cell, and second data different from the first data is written in the second memory cell through the writing operation. In a first loop of the writing operation, a first voltage is applied to the first bit line and the second bit line is maintained in an electrically floating state during the programming operation, and a verification operation relating to the second data is not performed and a verification operation relating to the first data is performed.
    Type: Application
    Filed: August 10, 2016
    Publication date: June 22, 2017
    Inventors: Hiroshi MAEJIMA, Koji HOSONO, Tadashi YASUFUKU, Noboru SHIBATA
  • Patent number: 9036443
    Abstract: A booster circuit is configured, such that: in response to a reading request for reading data from a flash memory, when a voltage of an output terminal detected by a voltage detection circuit is not higher than a voltage, an oscillator outputs a control clock signal of predetermined on time and off time to a transistor of a boost converter to perform switching control of the transistor; and when the voltage detection circuit detects that the voltage of the output terminal reaches a voltage, an oscillator outputs a control clock signal of an on time and an off time input from a selection circuit to a transistor of a boost converter to perform switching control of the transistor.
    Type: Grant
    Filed: May 11, 2012
    Date of Patent: May 19, 2015
    Assignee: THE UNIVERSITY OF TOKYO
    Inventors: Ken Takeuchi, Teruyoshi Hatanaka, Koichi Ishida, Tadashi Yasufuku, Makoto Takamiya, Takayasu Sakurai
  • Publication number: 20150078102
    Abstract: A nonvolatile semiconductor memory device includes a first data latch, a second data latch, and a data bus between the first and second data latches. A first transistor is electrically connected between the first data latch and the data bus and a second transistor is electrically connected between the data bus and the second data latch. A control unit controls charging of the data bus based on an output of the first data latch.
    Type: Application
    Filed: February 24, 2014
    Publication date: March 19, 2015
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventor: Tadashi YASUFUKU
  • Patent number: 8742838
    Abstract: The interposer 30 is disposed on an upper surface of the stacked structure 24 formed by stacking a plurality of a DRAM chip 20 and a plurality of a flash memory chip 22. Thus down-size of an entire device is accomplished. A boost converter having an inductor is used as a voltage boost circuit 40. Thus down-size of the entire device is accomplished.
    Type: Grant
    Filed: April 17, 2009
    Date of Patent: June 3, 2014
    Assignee: The University of Tokyo
    Inventors: Ken Takeuchi, Tadashi Yasufuku, Koichi Ishida, Makoto Takamiya, Takayasu Sakurai
  • Publication number: 20140104952
    Abstract: A booster circuit is configured, such that: in response to a reading request for reading data from a flash memory, when a voltage of an output terminal detected by a voltage detection circuit is not higher than a voltage, an oscillator outputs a control clock signal of predetermined on time and off time to a transistor of a boost converter to perform switching control of the transistor; and when the voltage detection circuit detects that the voltage of the output terminal reaches a voltage, an oscillator outputs a control clock signal of an on time and an off time input from a selection circuit to a transistor of a boost converter to perform switching control of the transistor.
    Type: Application
    Filed: May 11, 2012
    Publication date: April 17, 2014
    Applicant: THE UNIVERSITY OF TOKYO
    Inventors: Ken Takeuchi, Teruyoshi Hatanaka, Koichi Ishida, Tadashi Yasufuku, Makoto Takamiya, Takayasu Sakurai
  • Patent number: 8514013
    Abstract: The channel number detecting circuit detects the operation channel number based on the output terminal voltage after falling down when the output terminal voltage falls down during the voltage boosting control, and the switching control circuit generates the control clock signal having the on-time and the off-time adjusted based on the operation channel number and performs the voltage boosting control using generating control clock signal. The voltage boosting control is properly performed based on the operation channel number when the operation channel number increase during performing the voltage boosting control. Thus boosting the power supply voltage up to a second voltage is accomplished.
    Type: Grant
    Filed: April 25, 2011
    Date of Patent: August 20, 2013
    Assignee: The University of Tokyo
    Inventors: Ken Takeuchi, Teruyoshi Hatanaka, Koichi Ishida, Tadashi Yasufuku, Makoto Takamiya, Takayasu Sakurai
  • Publication number: 20110298534
    Abstract: The channel number detecting circuit 50 detects the operation channel number Nch based on the the output terminal voltage Vpgm after falling down when the output terminal voltage Vpgm falls down during the voltage boosting control, and the switching control circuit 70 generates the control clock signal CLK having the on-time and the off-time adjusted based on the operation channel number Nch and performs the voltage boosting control using generating control clock signal CLK. The voltage boosting control is properly performed based on the operation channel number Nch when the operation channel number Nch increase during performing the voltage boosting control. Thus boosting the power supply voltage Vdd up to the voltage V2 is accomplished.
    Type: Application
    Filed: April 25, 2011
    Publication date: December 8, 2011
    Applicant: THE UNIVERSITY OF TOKYO
    Inventors: Ken TAKEUCHI, Teruyoshi HATANAKA, Koichi ISHIDA, Tadashi YASUFUKU, Makoto TAKAMIYA, Takayasu SAKURAI
  • Publication number: 20110260781
    Abstract: The interposer is disposed on an upper surface of the stacked structure formed by stacking a plurality of a DRAM chip and a plurality of a flash memory chip. Thus down-size of an entire device is accomplished. A boost converter having an inductor is used as a voltage boost circuit. Thus down-size of the entire device is accomplished in comparison to a voltage boost circuit using a charge pump connected in parallel with a plurality of a capacitance.
    Type: Application
    Filed: April 17, 2009
    Publication date: October 27, 2011
    Applicant: THE UNIVERSITY OF TOKYO
    Inventors: Ken Takeuchi, Tadashi Yasufuku, Koichi Ishida, Makoto Takamiya, Takayasu Sakurai