Patents by Inventor Naoya Tokiwa

Naoya Tokiwa 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: 7911823
    Abstract: A method of programming a non-volatile memory device with memory cells formed of variable resistance elements and disposed between word lines and bit lines, includes: previously charging a selected word line and a selected bit line together with a non-selected word line and a non-selected bit line up to a certain voltage; and further charging the selected word line and the non-selected bit line up to a program voltage higher than the certain voltage and a program-block voltage, respectively, and simultaneously discharging the selected bit line.
    Type: Grant
    Filed: May 20, 2008
    Date of Patent: March 22, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Takuya Futatsuyama, Koji Hosono, Toshiaki Edahiro, Naoya Tokiwa, Kazushige Kanda, Shigeo Ohshima
  • Patent number: 7911854
    Abstract: A semiconductor memory device comprises a plurality of memory layers arranged in multilayer, each memory layer including a cell array, the cell array containing a plurality of first parallel lines, a plurality of second parallel lines arranged crossing the first lines, and a plurality of memory cells connected at intersections of the first lines and the second lines; a pulse generator operative to generate pulses required for data access to the memory cell; and a control means operative to control the pulse generator such that the pulse output from the pulse generator has energy in accordance with the memory layer to which the access target memory cell belongs.
    Type: Grant
    Filed: February 27, 2009
    Date of Patent: March 22, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiroyuki Nagashima, Naoya Tokiwa
  • Publication number: 20110066900
    Abstract: A non-volatile memory device including: a memory cell array storing an electrically rewritable resistance value as data in a non-volatile manner; a first cache circuit configured to hold program data to be programmed in the cell array; a second cache circuit configured to hold preprogrammed data read from an area of the cell array; and a judging circuit configured to compare and check the program data with the preprogrammed data, and judge whether there are one or more disagreement bits therebetween or not.
    Type: Application
    Filed: December 30, 2009
    Publication date: March 17, 2011
    Applicant: Kabushiki Kaisha Toshiba
    Inventor: Naoya TOKIWA
  • Patent number: 7889537
    Abstract: The present invention provides a method for writing data to a non-volatile memory device having first wirings and second wirings intersecting one another and memory cells arranged at each intersection therebetween, each of the memory cells having a variable resistive element and a rectifying element connected in series. According to the method, the second wirings are charged to a certain voltage not less than a rectifying-element threshold value, prior to a rise in a selected first wiring. Then, a selected first wiring is charged to a voltage required for writing or erasing, after which a selected second wiring is discharged.
    Type: Grant
    Filed: May 9, 2008
    Date of Patent: February 15, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Toshiaki Edahiro, Kazushige Kanda, Naoya Tokiwa, Takuya Futatsuyama, Koji Hosono, Shigeo Ohshima
  • Patent number: 7876626
    Abstract: A semiconductor memory device comprises a memory cell array including a plurality of memory cells arranged at intersections of word lines and bit lines; a read/write circuit operative to execute data read/write to the memory cell; and an operational circuit operative to compare certain length data read out by the read/write circuit from plural ones of the memory cells with certain length data to be written in the plural memory cells to make a decision, and create a flag representing the decision result. The read/write circuit inverts each bit in the certain length data to be written in the memory cells in accordance with the flag, and writes only rewrite-intended data of the certain length data and the flag. The read/write circuit reads the certain length data together with the flag corresponding thereto, and inverts each bit in the certain length data in accordance with the flag.
    Type: Grant
    Filed: March 20, 2009
    Date of Patent: January 25, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hideo Mukai, Hiroshi Maejima, Satoru Takase, Naoya Tokiwa, Katsuaki Isobe
  • Patent number: 7864580
    Abstract: A nonvolatile semiconductor storage device is disclosed, which includes a memory cell array in which nonvolatile memory cells are arranged, a first data holding circuit which temporarily holds a collective processing unit of read or write data to be simultaneously read from or written to the memory cells, a circuit which takes out the data held in the first data holding circuit from the device, and a second data holding circuit in which data is automatically set at a time when power supply is turned on and in which the data is changeable based on a command input to the device, wherein the collective processing unit is equal to a sum of the number of units used within the device and the maximum number of units continuously output from the device to outside or input to the device from outside.
    Type: Grant
    Filed: April 27, 2010
    Date of Patent: January 4, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Naoya Tokiwa
  • Patent number: 7864586
    Abstract: A non-volatile semiconductor memory device includes: a memory cell array with electrically rewritable and non-volatile memory cells arranged therein; a first register group configured to store control data used for controlling memory operations; an adjusting data storage area defined in the memory cell array so as to store adjusting data used for adjusting the control data; and a second register group configured to store the adjusting data read from the adjusting data storage area.
    Type: Grant
    Filed: November 25, 2008
    Date of Patent: January 4, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Naoya Tokiwa
  • Patent number: 7835174
    Abstract: The present invention provides a method of reading data from a non-volatile memory device including word lines and bit lines that intersect each other and electrically rewritable memory cells that are arranged at intersections of the word lines and the bit lines and that respectively have variable resistive elements nonvolatily storing a resistances as data. The method includes: precharging a selected word line and unselected word lines to a first word line voltage and a selected bit line and unselected bit lines to a first bit line voltage; and reading data from a memory cell connected to the selected word line and the selected bit line by changing the voltage of the selected word line from the first word line voltage to a second word line voltage and changing the voltage of the selected bit line from the first bit line voltage to a second bit line voltage after the precharging.
    Type: Grant
    Filed: November 7, 2008
    Date of Patent: November 16, 2010
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Naoya Tokiwa
  • Publication number: 20100277968
    Abstract: A semiconductor memory device includes a memory cell array configured of at least a first portion and a second portion each including a plurality of memory cells each with a variable resistor which stores an electrically rewritable resistance value as a data, and a control circuit which controls a first operation including selected one of operations to erase, write and read the data in the first portion and a second operation including selected one of operations to erase, write and read the data in the second portion, the first operation and the second operation being performed in temporally overlapped relation with each other.
    Type: Application
    Filed: April 29, 2010
    Publication date: November 4, 2010
    Inventor: Naoya TOKIWA
  • Patent number: 7817457
    Abstract: According to one embodiment, a nonvolatile memory device includes: a memory cell array including memory cells each having a variable resistance element for nonvolatilely storing data identified by an electrically rewritable resistance value; a first data latch storing write and erase data to be written on a given group of memory cells of the memory cell array for a write and erase operation; and a second data latch storing reference data for performing a compensation operation of the given group to compensate write and erase disturbance accompanied by the write or erase operation.
    Type: Grant
    Filed: June 4, 2008
    Date of Patent: October 19, 2010
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Naoya Tokiwa, Kazushige Kanda, Toshiaki Edahiro, Koji Hosono, Takuya Futatsuyama, Shigeo Ohshima
  • Publication number: 20100238706
    Abstract: A nonvolatile semiconductor storage device includes a memory core that includes plural banks, the bank including plural memory cells and a data write circuit that supplies a bias voltage to the memory cell, the memory core being logically divided into plural pages, the page including a predetermined number of memory cells belonging to a predetermined number of banks; and a control circuit that controls the data write circuit to perform page write in each write unit including a predetermined number of memory cells, pieces of data being written in the page in the page write, the control circuit performing the page write by repeating a step including a program operation and a verify operation, the control circuit performing the program operation and the verify operation in a next step or later only to the write unit in which the data write is not completed in the verify operation.
    Type: Application
    Filed: February 19, 2010
    Publication date: September 23, 2010
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Naoya TOKIWA, Hiroshi Maejima
  • Patent number: 7800935
    Abstract: A resistance change memory device including memory cells arranged, the memory cell having a stable state with a high resistance value and storing in a non-volatile manner such multi-level data that at least three resistance values, R0, R1 and R2 (R0<R1<R2) are selectively set, wherein resistance gaps ?R1(=R1?R0) and ?R2(=R2?R1) are set to satisfy the relationship of ?R1>?R2.
    Type: Grant
    Filed: October 16, 2008
    Date of Patent: September 21, 2010
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiroshi Maejima, Katsuaki Isobe, Naoya Tokiwa, Satoru Takase, Yasuyuki Fukuda, Hideo Mukai, Tsuneo Inaba
  • Publication number: 20100202228
    Abstract: A nonvolatile semiconductor storage device is disclosed, which includes a memory cell array in which nonvolatile memory cells are arranged, a first data holding circuit which temporarily holds a collective processing unit of read or write data to be simultaneously read from or written to the memory cells, a circuit which takes out the data held in the first data holding circuit from the device, and a second data holding circuit in which data is automatically set at a time when power supply is turned on and in which the data is changeable based on a command input to the device, wherein the collective processing unit is equal to a sum of the number of units used within the device and the maximum number of units continuously output from the device to outside or input to the device from outside.
    Type: Application
    Filed: April 27, 2010
    Publication date: August 12, 2010
    Inventor: Naoya TOKIWA
  • Publication number: 20100188920
    Abstract: A nonvolatile semiconductor memory device has an internal step-down power generation circuit and a memory circuit. The internal step-down power generation circuit generates a first internal power supply voltage from an external power supply voltage in an active state, and generates a second internal power supply voltage different from the first internal power supply voltage from the external power supply voltage in a standby state. The memory circuit includes a cell array containing a nonvolatile memory cell and a sense amplifier detecting data read from the cell array. The sense amplifier is supplied with a voltage generated by the internal step-down power generation circuit as an internal power supply voltage.
    Type: Application
    Filed: January 26, 2010
    Publication date: July 29, 2010
    Inventors: Takuya FUTATSUYAMA, Naoya Tokiwa
  • Patent number: 7724573
    Abstract: A nonvolatile semiconductor storage device is disclosed, which includes a memory cell array in which nonvolatile memory cells are arranged, a first data holding circuit which temporarily holds a collective processing unit of read or write data to be simultaneously read from or written to the memory cells, a circuit which takes out the data held in the first data holding circuit from the device, and a second data holding circuit in which data is automatically set at a time when power supply is turned on and in which the data is changeable based on a command input to the device, wherein the collective processing unit is equal to a sum of the number of units used within the device and the maximum number of units continuously output from the device to outside or input to the device from outside.
    Type: Grant
    Filed: February 29, 2008
    Date of Patent: May 25, 2010
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Naoya Tokiwa
  • Publication number: 20100097858
    Abstract: A three-dimensionally stacked nonvolatile semiconductor memory of an aspect of the present invention including conductive layers stacked on a semiconductor substrate in such a manner as to be insulated from one another, a bit line which is disposed on the stacked conductive layers, a semiconductor column which extends through the stacked conductive layers, word lines for which the stacked conductive layers except for the uppermost and lowermost conductive layers are used and which have a plate-like planar shape, memory cells provided at intersections of the word lines and the semiconductor column, a register circuit which has information to supply a potential suitable for each of the word lines, and a potential control circuit which reads the information retained in the register circuit in accordance with an input address signal of a word line and which supplies a potential suitable for the word line corresponding to the address signal.
    Type: Application
    Filed: September 3, 2009
    Publication date: April 22, 2010
    Inventors: Naoya Tokiwa, Hideo Mukai
  • Publication number: 20100037007
    Abstract: A nonvolatile semiconductor memory device includes a memory cell array in which memory cells having an electrically rewritable charge accumulation layer are arranged, a data writing/reading circuit that writes/reads data to/from the memory cell array in units of pages, a write state information storage circuit for nonvolatile storage of write state information indicating a data write state to the memory cell array by the data writing/reading circuit, and a control circuit that controls the data writing/reading circuit based on an access page address indicating a page from which data is about to be read by the data writing/reading circuit and write state information stored in the write state information storage circuit.
    Type: Application
    Filed: August 3, 2009
    Publication date: February 11, 2010
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: TAKUYA FUTATSUYAMA, NAOYA TOKIWA, TOSHIAKI EDAHIRO, YOSHIHIKO SHINDO
  • Publication number: 20100034025
    Abstract: There is provided a non-volatile memory having electrically rewritable non-volatile memory cells arranged therein. A controller controls operation at the non-volatile memory. The non-volatile memory comprises a status output section configured to output status information indicating a status of read operation, write operation or erase operation in the non-volatile memory cell. The controller comprises a control signal generating section configured to output a control signal for a certain operation in the non-volatile memory, and a control signal switching section configured to instruct the control signal generating section to switch the control signal based on the status information.
    Type: Application
    Filed: July 22, 2009
    Publication date: February 11, 2010
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Kosuke YANAGIDAIRA, Toshihiro Suzuki, Naoya Tokiwa
  • Publication number: 20100027341
    Abstract: A memory may include word lines; bit lines; cells provided corresponding to intersections between the word lines and the bit lines; sense amplifiers detecting data; a column decoder selecting a certain bit line for the sense amplifiers to output read data or receive write data; a row decoder configured to select a certain word line; a charge pump supplying power to the sense amplifiers, the column decoder, and the row decoder; a logic circuit controlling the sense amplifiers, the column decoder, and the row decoder based on an address selecting the memory cells; a first power source input applying a voltage to the logic circuit; and a second power source input applying a voltage higher than a voltage of the first power source input to the charge pump, and to supply power to the charge pump at least at a data reading time and a data writing time.
    Type: Application
    Filed: July 31, 2009
    Publication date: February 4, 2010
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Naoya TOKIWA, Shigeo OHSHIMA
  • Publication number: 20090237979
    Abstract: A semiconduct or memory device comprises a memory cell array including a plurality of memory cells arranged at intersections of word lines and bit lines; a read/write circuit operative to execute data read/write to the memory cell; and an operational circuit operative to compare certain length data read out by the read/write circuit from plural ones of the memory cells with certain length data to be written in the plural memory cells to make a decision, and create a flag representing the decision result. The read/write circuit inverts each bit in the certain length data to be written in the memory cells in accordance with the flag, and writes only rewrite-intended data of the certain length data and the flag. The read/write circuit reads the certain length data together with the flag corresponding thereto, and inverts each bit in the certain length data in accordance with the flag.
    Type: Application
    Filed: March 20, 2009
    Publication date: September 24, 2009
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Hideo Mukai, Hiroshi Maejima, Satoru Takase, Naoya Tokiwa, Katsuaki Isobe