Patents by Inventor Kohei Oikawa

Kohei Oikawa 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).

  • Publication number: 20060181339
    Abstract: A semiconductor device includes first, second, third and fourth resistor elements. The first to fourth resistor elements have first ends commonly connected to a first node, and operate in one of first and second operation modes which are switchable. The first and second resistor elements have second ends connected to a second node and a third node, respectively. The third and fourth resistor elements have second ends connected to a fourth node and a fifth node via a first switch and a second switch, respectively. The first and second switches are opened in the first operation mode, and are closed in the second operation mode.
    Type: Application
    Filed: April 11, 2006
    Publication date: August 17, 2006
    Inventors: Shinichiro Shiratake, Kohei Oikawa
  • Patent number: 7053696
    Abstract: A semiconductor device includes first, second, third and fourth resistor elements. The first to fourth resistor elements have first ends commonly connected to a first node, and operate in one of first and second operation modes which are switchable. The first and second resistor elements have second ends connected to a second node and a third node, respectively. The third and fourth resistor elements have second ends connected to a fourth node and a fifth node via a first switch and a second switch, respectively. The first and second switches are opened in the first operation mode, and are closed in the second operation mode.
    Type: Grant
    Filed: October 16, 2003
    Date of Patent: May 30, 2006
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Shinichiro Shiratake, Kohei Oikawa
  • Patent number: 7046540
    Abstract: A semiconductor integrated circuit device includes a cell array having a plurality of memory cells, a peripheral circuit which controls the cell array, and an operation information determination circuit. The operation information determination circuit determines either of a first operation mode in which one bit is stored by using one memory cell and a second operation mode in which one bit is stored by using two memory cells, and supplies operation information to the peripheral circuit. The operation information determines which of the first and second operation modes is used to operate the cell array.
    Type: Grant
    Filed: December 23, 2003
    Date of Patent: May 16, 2006
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Kohei Oikawa
  • Patent number: 7016216
    Abstract: A ferroelectric memory device includes memory cells, a memory cell block, a sense amplifier, a precharge circuit, a bit line drive circuit, and a plate line drive circuit. Each of the memory cells has a cell transistor and a ferroelectric capacitor in between a source and drain of the cell transistor. The memory cell block includes the memory cells that are series connected between a bit line via a block select transistor and a plate line. The sense amplifier amplifies data read out from the memory cell, and generates one of a first potential and a second potential higher than the first potential in accordance with the read-out data. The precharge circuit precharges the bit line at a third potential that is higher than the first potential and lower than the second potential. The bit line drive circuit sets the bit line at a fourth potential.
    Type: Grant
    Filed: October 8, 2003
    Date of Patent: March 21, 2006
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kohei Oikawa, Shinichiro Shiratake, Daisaburo Takashima
  • Patent number: 7002871
    Abstract: A semiconductor integrated circuit device includes an address buffer which receives an address signal that indicates an address of a memory cell array, a latch circuit which latches the data, and an address transition detection circuit which detects transition of the address. During the access operation of the memory cell array, an address at the operation start time is latched by the latch circuit. After the end of the operation of the memory cell array, an address that is currently input to the address buffer is latched by the latch circuit. If the received address signal is data different from the latch data, a control signal that controls the cycle operation of the memory cell array for a predetermined period is generated on the basis of the detection result from the address transition detection circuit.
    Type: Grant
    Filed: January 23, 2004
    Date of Patent: February 21, 2006
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yoshiaki Takeuchi, Kohei Oikawa
  • Publication number: 20060018144
    Abstract: An aspect of the present invention provides a ferroelectric memory comprising a cell block having a plurality of unit cells connected in series, one end of the cell block being connected to a plate line and the other end of the cell block being connected to a bit line through a block selecting transistor, a sense amplifier connected to the bit line, and a block selector decoder which controls ON/OFF of the block selecting transistor. The timing for operating the sense amplifier and block selector decoder is changed corresponding to a position of a selected unit cell objective for data read of the plurality of unit cells.
    Type: Application
    Filed: September 7, 2004
    Publication date: January 26, 2006
    Inventors: Kohei Oikawa, Daisaburo Takashima
  • Publication number: 20060020836
    Abstract: A circuit according to an embodiment of the present invention comprises a first power supply region supplied with a first power supply voltage, and having a first clock distribution network, a second power supply region supplied with a second power supply voltage, and having a second clock distribution network, a PLL circuit which provides a first output signal obtained by making a phase of a reference clock signal for controlling a data input/output coincident with a phase of a clock signal at an end point of the first clock distribution network, to a start point of the first clock distribution network, and a PLL circuit which provides a second output signal obtained by making the phase of the reference clock signal coincident with a phase of a clock signal at an end point of the second clock distribution network, to a start point of the second clock distribution network.
    Type: Application
    Filed: September 7, 2004
    Publication date: January 26, 2006
    Inventor: Kohei Oikawa
  • Publication number: 20050172177
    Abstract: A semiconductor memory device includes a memory array having at least a first area and a second area, which stores cell data, a data input circuit located closer to the first area than the second area, to which the cell data is input, and an error correction circuit which generates parity data for error correction from the cell data input to the data input circuit. The device further includes a control circuit which stores the parity data in the first area.
    Type: Application
    Filed: April 14, 2004
    Publication date: August 4, 2005
    Inventor: Kohei Oikawa
  • Patent number: 6901026
    Abstract: A semiconductor integrated circuit device includes a memory, /CE transition detector, address transition detector, /WE transition detector and controller. The controller includes a timeout circuit. The timeout circuit generates an internal circuit control signal with preset width to control access to the memory based on detection results of the above transition detectors. The operation of the memory is controlled by the timeout circuit at the read time. The operation of the memory is controlled by the timeout circuit when transition of the end of a /WE signal is detected by the /WE transition detector before a timing specified by the timeout circuit at the write time. Further, the operation of the memory is controlled in response to the transition of the /WE signal when the transition of the end of the /WE signal is detected by the /WE transition detector after passage of the above timing.
    Type: Grant
    Filed: February 14, 2003
    Date of Patent: May 31, 2005
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yoshiaki Takeuchi, Shinichiro Shiratake, Kohei Oikawa
  • Publication number: 20050068837
    Abstract: A semiconductor integrated circuit device includes an address buffer which receives an address signal that indicates an address of a memory cell array, a latch circuit which latches the data, and an address transition detection circuit which detects transition of the address. During the access operation of the memory cell array, an address at the operation start time is latched by the latch circuit. After the end of the operation of the memory cell array, an address that is currently input to the address buffer is latched by the latch circuit. If the received address signal is data different from the latch data, a control signal that controls the cycle operation of the memory cell array for a predetermined period is generated on the basis of the detection result from the address transition detection circuit.
    Type: Application
    Filed: January 23, 2004
    Publication date: March 31, 2005
    Inventors: Yoshiaki Takeuch, Kohei Oikawa
  • Publication number: 20050057955
    Abstract: A semiconductor integrated circuit device includes a cell array having a plurality of memory cells, a peripheral circuit which controls the cell array, and an operation information determination circuit. The operation information determination circuit determines either of a first operation mode in which one bit is stored by using one memory cell and a second operation mode in which one bit is stored by using two semiconductor memory cells, and supplies operation information to the peripheral circuit. The operation information determines which of the first and second operation modes is used to operate the cell array.
    Type: Application
    Filed: December 23, 2003
    Publication date: March 17, 2005
    Inventor: Kohei Oikawa
  • Patent number: 6765831
    Abstract: A semiconductor integrated circuit device includes a memory array, address buffer, address decoder, and controller. The memory array includes a memory cell array in which destructive read-out memory cells are integrated. The address buffer outputs an internal address signal corresponding to an input external address signal. The address decoder decodes the internal address signal and outputs a memory cell selection signal on the basis of the decode result. The controller parallel-executes wait processing of keeping the address buffer in a wait state until the lapse of a skew time after transition of the external address signal is detected, and decode processing until the memory cell selection signal changes from an invalid state to a valid state in response to output of the internal address signal.
    Type: Grant
    Filed: May 5, 2003
    Date of Patent: July 20, 2004
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kohei Oikawa, Shinichiro Shiratake, Daisaburo Takashima
  • Publication number: 20040129980
    Abstract: A semiconductor device includes first, second, third and fourth resistor elements. The first to fourth resistor elements have first ends commonly connected to a first node, and operate in one of first and second operation modes which are switchable. The first and second resistor elements have second ends connected to a second node and a third node, respectively. The third and fourth resistor elements have second ends connected to a fourth node and a fifth node via a first switch and a second switch, respectively. The first and second switches are opened in the first operation mode, and are closed in the second operation mode.
    Type: Application
    Filed: October 16, 2003
    Publication date: July 8, 2004
    Inventors: Shinichiro Shiratake, Kohei Oikawa
  • Publication number: 20040125642
    Abstract: A ferroelectric memory device includes memory cells, a memory cell block, a sense amplifier, a precharge circuit, a bit line drive circuit, and a plate line drive circuit. Each of the memory cells has a cell transistor and a ferroelectric capacitor in between a source and drain of the cell transistor. The memory cell block includes the memory cells that are series connected between a bit line via a block select transistor and a plate line. The sense amplifier amplifies data read out from the memory cell, and generates one of a first potential and a second potential higher than the first potential in accordance with the read-out data. The precharge circuit precharges the bit line at a third potential that is higher than the first potential and lower than the second potential. The bit line drive circuit sets the bit line at a fourth potential.
    Type: Application
    Filed: October 8, 2003
    Publication date: July 1, 2004
    Inventors: Kohei Oikawa, Shinichiro Shiratake, Daisaburo Takashima
  • Publication number: 20040123085
    Abstract: A semiconductor device includes an internal power supply, at least one semiconductor circuit block, a delay circuit, and a detecting circuit. The internal power supply outputs an initialization completion signal when initialized. The semiconductor circuit block operates on the basis of a voltage generated by the internal power supply. The delay circuit delays the initialization completion signal. The detecting circuit commands the semiconductor circuit block to start operations in response to the initialization completion signal delayed by the delay circuit and an externally input first input signal.
    Type: Application
    Filed: December 19, 2002
    Publication date: June 24, 2004
    Inventors: Kohei Oikawa, Shinichiro Shiratake, Yoshiaki Takeuchi, Daisaburo Takashima, Thomas Roehr
  • Patent number: 6744302
    Abstract: A voltage generator circuit generates a voltage supplied to an internal circuit. The voltage generator circuit includes first, second, and third switching elements each having first and second terminals. The first terminal of each of the switching elements is connected to the power source terminal supplied with a power source voltage. First, second, and third transistors each have a current path which has first and second ends. The first ends of the first, second, and third transistors are respectively connected to the second terminals of the first, second, and third switching elements. The first, second, and third transistors have respectively first, second, and third driving capabilities. The first, second, and third driving capabilities are different from each other. The second ends of the current paths of the first, second, and third transistors are connected to an output terminal which outputs the voltage supplied to the internal circuit.
    Type: Grant
    Filed: December 5, 2002
    Date of Patent: June 1, 2004
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kohei Oikawa, Shinichiro Shiratake, Daisaburo Takashima
  • Patent number: 6744305
    Abstract: A power supply circuit includes a transistor, a variable resistance circuit, a second resistance, and an operational amplifier. The variable resistance circuit includes a plurality of first resistances. The plurality of first resistances are selected in response to control signals. The selected first resistances are connected in series with the transistor, the unselected first resistances are connected to a ground voltage. The second resistance is connected between the variable resistance circuit and the ground voltage. The operational amplifier compares a voltage of the one end of the variable resistance circuit with a reference voltage and feeds a signal indicating a comparison result back to the gate of the transistor.
    Type: Grant
    Filed: September 4, 2002
    Date of Patent: June 1, 2004
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kohei Oikawa, Shinichiro Shiratake
  • Publication number: 20040076066
    Abstract: A semiconductor integrated circuit device includes a memory array, address buffer, address decoder, and controller. The memory array includes a memory cell array in which destructive read-out memory cells are integrated. The address buffer outputs an internal address signal corresponding to an input external address signal. The address decoder decodes the internal address signal and outputs a memory cell selection signal on the basis of the decode result. The controller parallel-executes wait processing of keeping the address buffer in a wait state until the lapse of a skew time after transition of the external address signal is detected, and decode processing until the memory cell selection signal changes from an invalid state to a valid state in response to output of the internal address signal.
    Type: Application
    Filed: May 5, 2003
    Publication date: April 22, 2004
    Inventors: Kohei Oikawa, Shinichiro Shiratake, Daisaburo Takashima
  • Publication number: 20030156489
    Abstract: A semiconductor integrated circuit device includes a memory, /CE transition detector, address transition detector, /WE transition detector and controller. The controller includes a timeout circuit. The timeout circuit generates an internal circuit control signal with preset width to control access to the memory based on detection results of the above transition detectors. The operation of the memory is controlled by the timeout circuit at the read time. The operation of the memory is controlled by the timeout circuit when transition of the end of a /WE signal is detected by the /WE transition detector before a timing specified by the timeout circuit at the write time. Further, the operation of the memory is controlled in response to the transition of the /WE signal when the transition of the end of the /WE signal is detected by the /WE transition detector after passage of the above timing.
    Type: Application
    Filed: February 14, 2003
    Publication date: August 21, 2003
    Inventors: Yoshiaki Takeuchi, Shinichiro Shiratake, Kohei Oikawa
  • Publication number: 20030107362
    Abstract: A voltage generator circuit generates a voltage supplied to an internal circuit. The voltage generator circuit includes first, second, and third switching elements each having first and second terminals. The first terminal of each of the switching elements is connected to the power source terminal supplied with a power source voltage. First, second, and third transistors each have a current path which has first and second ends. The first ends of the first, second, and third transistors are respectively connected to the second terminals of the first, second, and third switching elements. The first, second, and third transistors have respectively first, second, and third driving capabilities. The first, second, and third driving capabilities are different from each other. The second ends of the current paths of the first, second, and third transistors are connected to an output terminal which outputs the voltage supplied to the internal circuit.
    Type: Application
    Filed: December 5, 2002
    Publication date: June 12, 2003
    Inventors: Kohei Oikawa, Shinichiro Shiratake, Daisaburo Takashima