Patents by Inventor Toshimasa Namekawa

Toshimasa Namekawa 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: 7630226
    Abstract: A memory cell includes: an irreversible storage element that writes data by breaking down an insulating film, with a write voltage being applied to its one end; and first and second transistors with one end being connected to the other end of the irreversible storage element. A non-volatile semiconductor storage device includes: the memory cell; write word lines and read word lines that are connected to the first transistor and the second transistor, respectively; write bit lines and read bit lines that are connected to the first transistor and the other end of the second transistor, respectively; a row decoder selectively driving the write word lines and the read word lines; and a write-disturb prevention circuit charging the read bit lines to a certain voltage in writing data.
    Type: Grant
    Filed: January 9, 2008
    Date of Patent: December 8, 2009
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kensuke Matsufuji, Toshimasa Namekawa
  • Patent number: 7613062
    Abstract: A semiconductor memory device includes a memory element, a first data line and a second data line, a first selection transistor, and a second selection transistor. The memory element includes a semiconductor element of MOS structure in which data is programmed when an insulating film provided in the semiconductor element is broken down by application of a voltage thereto. The first and second data lines are connected to a sense amplifier. The first selection transistor is configured to connect the memory element to the first data line in order to program data in the memory element. The second selection transistor is configured to connect the memory element to the second data line in order to program data in the memory element and detect the data programmed in the memory element. The second selection transistor has a smaller gate-electrode width smaller than the first selection transistor.
    Type: Grant
    Filed: April 23, 2007
    Date of Patent: November 3, 2009
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiroaki Nakano, Toshimasa Namekawa, Hiroshi Ito, Osamu Wada, Atsushi Nakayama
  • Patent number: 7599206
    Abstract: A non-volatile semiconductor storage device includes: one or more memory cells including anti-fuse elements capable of writing data by breaking down a gate insulation film of a MOS transistor with a high voltage; a sense node having its one end connected to each of the anti-fuse elements; a sense amplifier comparing the potential of the sense node with the reference potential and amplifying the difference therebetween, the sense amplifier being activated according to a sense-amplifier activation signal; an initialization circuit initializing the potential of the sense node according to an initialization signal; a control circuit outputting the initialization signal at a predetermined timing after input of an external signal input from the outside and outputting a first activation signal to activate the sense amplifier at a predetermined timing after input of the external signal; and a switching circuit outputting the first activation signal as the sense-amplifier activation signal when a normal data read oper
    Type: Grant
    Filed: February 15, 2008
    Date of Patent: October 6, 2009
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Atsushi Nakayama, Toshimasa Namekawa, Hiroaki Nakano, Hiroshi Ito, Osamu Wada
  • Patent number: 7590018
    Abstract: A differential input circuit receives differential input signals at a pair of differential input terminals and produces a pair of first differential output signals. A sensing circuit senses at least one of the pair of first differential output signals reaching a certain voltage and provides an activation signal. A latch-type amplifier provides a pair of second differential output signals when activated in accordance with the activation signal. A cutoff circuit establishes connection between the differential input circuit and the latch-type amplifier and breaks connection between the differential input circuit and the latch-type amplifier in accordance with the activation signal.
    Type: Grant
    Filed: February 29, 2008
    Date of Patent: September 15, 2009
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Toshimasa Namekawa
  • Publication number: 20090201076
    Abstract: A semiconductor charge pump includes a plurality of P-channel MOS transistors being connected in series, a plurality of first pumping capacitors one electrode of each of which is connected to a connection point of each of the P-channel MOS transistors, a clock signal generating circuit which generates first and second clock signals whose phases are different from each other by 180 degrees, the first and second clock signals being alternately supplied to the other electrodes of the first pumping capacitors. The semiconductor charge pump further includes a plurality of dynamic level converter circuits each including a resistor element and a second pumping capacitor and connected to each of gates of the P-channel MOS transistors.
    Type: Application
    Filed: April 15, 2009
    Publication date: August 13, 2009
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Toshimasa Namekawa, Hiroshi Ito
  • Patent number: 7557400
    Abstract: A semiconductor device has a MOS capacitor in which a drain region and a source region of a MOS structure are commonly connected, and a capacitance is formed between the commonly connected drain region/source region and a gate electrode of the MOS structure; and a wiring capacitor which has a first comb-shaped wiring that is formed on said MOS capacitor through an interlayer insulating film, is connected to the gate electrode of said MOS capacitor, and has projecting portions projecting like comb teeth and a second comb-shaped wiring that is formed on said MOS capacitor through the interlayer insulating film, is arranged across an inter-line insulating film from the first comb-shaped wiring, is connected to the drain region and source region, and has projecting portions projecting like comb teeth, wherein the projecting portions of the second comb-shaped wiring are arranged alternately with the projecting portions of the first comb-shaped wiring and arranged perpendicularly to a channel direction connecting t
    Type: Grant
    Filed: February 2, 2007
    Date of Patent: July 7, 2009
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Osamu Wada, Hiroaki Nakano, Hiroshi Ito, Toshimasa Namekawa, Atsushi Nakayama
  • Patent number: 7532062
    Abstract: A semiconductor charge pump includes a plurality of P-channel MOS transistors being connected in series, a plurality of first pumping capacitors one electrode of each of which is connected to a connection point of each of the P-channel MOS transistors, a clock signal generating circuit which generates first and second clock signals whose phases are different from each other by 180 degrees, the first and second clock signals being alternately supplied to the other electrodes of the first pumping capacitors. The semiconductor charge pump further includes a plurality of dynamic level converter circuits each including a resistor element and a second pumping capacitor and connected to each of gates of the P-channel MOS transistors.
    Type: Grant
    Filed: June 12, 2008
    Date of Patent: May 12, 2009
    Assignee: Kabusiki Kaisha Toshiba
    Inventors: Toshimasa Namekawa, Hiroshi Ito
  • Patent number: 7505300
    Abstract: A nonvolatile semiconductor memory device includes a nonvolatile storage element to which data is inhibited from being rewritten, a read operation control circuit which captures a read operation instruction signal in synchronization with an external input clock, and a write operation control circuit to which a write operation instruction signal is input asynchronously with the external input clock. The read operation instruction signal gives an instruction to start a read operation to read data out of the nonvolatile storage element, and the write operation instruction signal gives an instruction to start a write operation to write data to the nonvolatile storage element. The device further includes a reset circuit which resets an operation of the read operation control circuit upon receiving the write operation instruction signal.
    Type: Grant
    Filed: April 11, 2007
    Date of Patent: March 17, 2009
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Toshimasa Namekawa, Hiroshi Ito, Hiroaki Nakano, Osamu Wada, Atsushi Nakayama
  • Publication number: 20090027973
    Abstract: A non-volatile semiconductor storage device includes: one or more memory cells including anti-fuse elements capable of writing data by breaking down a gate insulation film of a MOS transistor with a high voltage; a sense node having its one end connected to each of the anti-fuse elements; a sense amplifier comparing the potential of the sense node with the reference potential and amplifying the difference therebetween, the sense amplifier being activated according to a sense-amplifier activation signal; an initialization circuit initializing the potential of the sense node according to an initialization signal; a control circuit outputting the initialization signal at a predetermined timing after input of an external signal input from the outside and outputting a first activation signal to activate the sense amplifier at a predetermined timing after input of the external signal; and a switching circuit outputting the first activation signal as the sense-amplifier activation signal when a normal data read oper
    Type: Application
    Filed: February 15, 2008
    Publication date: January 29, 2009
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Atsushi Nakayama, Toshimasa Namekawa, Hiroaki Nakano, Hiroshi Ito, Osamu Wada
  • Publication number: 20080316852
    Abstract: A nonvolatile semiconductor memory device comprises an array of memory cells each including an antifuse to store information based on a variation in resistance in accordance with destruction of the insulator in the antifuse. The antifuse includes a semiconductor substrate, a first conduction layer formed in the surface of the semiconductor substrate, a first electrode provided on the first conduction layer to be given a first voltage, a second conduction layer provided on the semiconductor substrate with the insulator interposed therebetween, and a second electrode provided on the second conduction layer to be given a second voltage different from the first voltage. The first electrode or the second electrode is formed of a metal silicide.
    Type: Application
    Filed: June 16, 2008
    Publication date: December 25, 2008
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Kensuke Matsufuji, Toshimasa Namekawa, Hiroshi Ito
  • Publication number: 20080246535
    Abstract: A semiconductor charge pump includes a plurality of P-channel MOS transistors being connected in series, a plurality of first pumping capacitors one electrode of each of which is connected to a connection point of each of the P-channel MOS transistors, a clock signal generating circuit which generates first and second clock signals whose phases are different from each other by 180 degrees, the first and second clock signals being alternately supplied to the other electrodes of the first pumping capacitors. The semiconductor charge pump further includes a plurality of dynamic level converter circuits each including a resistor element and a second pumping capacitor and connected to each of gates of the P-channel MOS transistors.
    Type: Application
    Filed: June 12, 2008
    Publication date: October 9, 2008
    Inventors: Toshimasa NAMEKAWA, Hiroshi Ito
  • Publication number: 20080237673
    Abstract: A semiconductor device comprising: a first well region which is formed at a surface portion of a semiconductor substrate and to which a first voltage is applied; a gate insulating film which is formed on the first well region; a gate electrode which is formed on the gate insulating film and has a polarity different from a polarity of the first well region and to which a second voltage is applied; and an element isolating region which is formed at a surface portion of the first well region to surround a region within the first well region that is opposed to the gate insulating film, wherein a capacitance is formed between the region within the first well region surrounded by the element isolating region and the gate electrode.
    Type: Application
    Filed: September 28, 2007
    Publication date: October 2, 2008
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Osamu Wada, Toshimasa Namekawa
  • Publication number: 20080212384
    Abstract: A differential input circuit receives differential input signals at a pair of differential input terminals and produces a pair of first differential output signals. A sensing circuit senses at least one of the pair of first differential output signals reaching a certain voltage and provides an activation signal. A latch-type amplifier provides a pair of second differential output signals when activated in accordance with the activation signal. A cutoff circuit establishes connection between the differential input circuit and the latch-type amplifier and breaks connection between the differential input circuit and the latch-type amplifier in accordance with the activation signal.
    Type: Application
    Filed: February 29, 2008
    Publication date: September 4, 2008
    Applicant: Kabushiki Kaisha Toshiba
    Inventor: Toshimasa NAMEKAWA
  • Publication number: 20080165586
    Abstract: A memory cell includes: an irreversible storage element that writes data by breaking down an insulating film, with a write voltage being applied to its one end; and first and second transistors with one end being connected to the other end of the irreversible storage element. A non-volatile semiconductor storage device includes: the memory cell; write word lines and read word lines that are connected to the first transistor and the second transistor, respectively; write bit lines and read bit lines that are connected to the first transistor and the other end of the second transistor, respectively; a row decoder selectively driving the write word lines and the read word lines; and a write-disturb prevention circuit charging the read bit lines to a certain voltage in writing data.
    Type: Application
    Filed: January 9, 2008
    Publication date: July 10, 2008
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Kensuke MATSUFUJI, Toshimasa Namekawa
  • Publication number: 20080165564
    Abstract: A memory cell array includes memory cells disposed in a matrix. A plurality of word-lines are arranged in the memory cell array to select a memory cell in a row direction. A read bit-line pair is arranged in a direction perpendicular to the word-line to read data from the memory cell. In addition, a write bit-line is arranged in a direction perpendicular to the word-line to write data to the memory cell. The read bit-line pair includes a true and a complementary read bit-line. One of the true and complementary read bit-lines is connected to the memory cell connected to an even-numbered word-line. The other one is connected to the memory cell connected to an odd-numbered word-line.
    Type: Application
    Filed: January 3, 2008
    Publication date: July 10, 2008
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventor: Toshimasa NAMEKAWA
  • Patent number: 7388770
    Abstract: A nonvolatile semiconductor memory device includes a storage element which is programmed with information by breaking an insulating film by application of electrical stress to the storage element, a control switch which controls the application of electrical stress to the storage element, and a control circuit which controls conduction/nonconduction of the control switch. The device further includes a power supply circuit including a voltage generation circuit which generates a first voltage to cause the electrical stress in program operation, a sensing circuit which senses that the insulating film is broken down, and a counter circuit which controls the control circuit to interrupt the application of electrical stress to the storage element when a given period of time elapses after the sensing circuit senses that the insulating film is broken down.
    Type: Grant
    Filed: September 9, 2005
    Date of Patent: June 17, 2008
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Toshimasa Namekawa, Hiroaki Nakano, Hiroshi Ito, Atsushi Nakayama, Osamu Wada
  • Patent number: 7382680
    Abstract: A semiconductor integrated circuit device includes a storage unit arranged on a semiconductor chip to store a plurality of data, and a plurality of registers provided on the semiconductor chip, the registers storing the data transferred from the storage unit, respectively. The storage unit has a nonvolatile memory element section and a volatile memory element section. The nonvolatile memory element section includes an address area which stores identification information of the registers as addresses and a data area which stores the data to correspond to the addresses by varying electrical characteristics irreversibly. The volatile memory element section temporarily stores the data read from the nonvolatile memory element section.
    Type: Grant
    Filed: September 12, 2006
    Date of Patent: June 3, 2008
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiroaki Nakano, Toshimasa Namekawa, Osamu Wada, Hiroshi Ito, Atsushi Nakayama
  • Publication number: 20080094898
    Abstract: A memory cell array includes a plurality of non-volatile semiconductor memory elements, each memory element storing data in a non-volatile manner. A shift register stores data read from the semiconductor memory element and sequentially transfers the data outside, the shift register also stores data transferred from outside and stores the data in the semiconductor memory element. A syndrome generation circuit is connected to an output terminal of the shift register, the syndrome generation circuit generating syndrome of data output from the output terminal. An error-correction circuit uses the data and the syndrome to correct an error of the data.
    Type: Application
    Filed: October 15, 2007
    Publication date: April 24, 2008
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Hiroaki Nakano, Toshimasa Namekawa, Hiroshi Ito, Osamu Wada, Atsushi Nakayama
  • Publication number: 20080080295
    Abstract: A semiconductor memory device includes a precharge unit to precharge a reference bit line and a selection bit line with the same potential, the selection bit line being connected to a target nonvolatile storage element from which data is to be read, a charge extraction unit to extract charges from the reference bit line and the selection bit line with the same current characteristic, a recharge unit which recharges the reference bit line with a current that is smaller than the charges extracted by the charge extraction unit, and a plurality of differential amplifiers which compare a potential of the reference bit line and a potential of the selection bit line with a reference potential. The semiconductor memory device further includes an output circuit which outputs data from the target nonvolatile storage element connected to the selection bit line, based on outputs of the differential amplifiers.
    Type: Application
    Filed: August 2, 2007
    Publication date: April 3, 2008
    Inventors: Toshimasa Namekawa, Hiroshi Ito, Osamu Wada, Atsushi Nakayama, Hiroaki Nakano
  • Patent number: 7345903
    Abstract: A nonvolatile semiconductor memory device having a storage element which is programmed with information by breaking an insulating film of the storage element, includes a cell array including a plurality of storage cells arranged in matrix, each of the storage cells having the storage element and a selection switch connected in series to the storage element, and a row selection control circuit which activates a row selection line connected to a given number of storage cells. The device further includes a write control circuit which controls a voltage of each of data lines bit by bit in accordance with write data, the data lines being connected to a given number of storage cells connected to the row selection line activated by the row selection control circuit.
    Type: Grant
    Filed: September 22, 2005
    Date of Patent: March 18, 2008
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiroaki Nakano, Toshimasa Namekawa, Atsushi Nakayama, Osamu Wada, Hiroshi Ito