Patents by Inventor Kiyoo Itoh

Kiyoo Itoh 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: 10319430
    Abstract: A memory includes a plurality of memory cells and a plurality of peripheral circuits. Each memory cell has a first inverter and a second inverter, the first inverter is supplied by a first power supply rail and a second power supply rail, and the second inverter is supplied by a third power supply rail and a fourth power supply rail. A first voltage difference is applied across the first power supply rail and the second power supply rail, a second voltage difference is applied across the third power supply rail and the fourth power supply rail, and the first voltage difference is less than the second voltage difference. The plurality of peripheral circuits use at least one of boosted power supplies corresponding to the second voltage difference and gate-source differentially-driven circuits.
    Type: Grant
    Filed: August 24, 2017
    Date of Patent: June 11, 2019
    Assignee: Etron Technology, Inc.
    Inventor: Kiyoo Itoh
  • Patent number: 10141047
    Abstract: A static random access memory (SRAM) comprises a plurality of memory cells each having a pair of cross-coupled inverters, a first of the inverters being supplied by first and second power supply rails and a second of the inverters being supplied by third and fourth supply rails, an input of the second inverter being coupled to a first bit line via a first transistor; and a power supply circuit adapted to apply a first voltage difference across the first and second power supply rails and a second voltage difference across the third and fourth power supply rails, the second voltage difference being greater than the first voltage difference.
    Type: Grant
    Filed: May 20, 2016
    Date of Patent: November 27, 2018
    Assignee: COMMISSARIAT A L'ENERGIE ATOMIQUE ET AUX ENERGIES
    Inventors: Kiyoo Itoh, Amara Amara, Khaja Ahmad Shaik
  • Publication number: 20180061486
    Abstract: A memory includes a plurality of memory cells and a plurality of peripheral circuits. Each memory cell has a first inverter and a second inverter, the first inverter is supplied by a first power supply rail and a second power supply rail, and the second inverter is supplied by a third power supply rail and a fourth power supply rail. A first voltage difference is applied across the first power supply rail and the second power supply rail, a second voltage difference is applied across the third power supply rail and the fourth power supply rail, and the first voltage difference is less than the second voltage difference. The plurality of peripheral circuits use at least one of boosted power supplies corresponding to the second voltage difference and gate-source differentially-driven circuits.
    Type: Application
    Filed: August 24, 2017
    Publication date: March 1, 2018
    Inventor: Kiyoo Itoh
  • Publication number: 20160372180
    Abstract: The invention concerns a static random access memory (SRAM) comprising: a plurality of memory cells each having a pair of cross-coupled inverters (102, 104), a first of the inverters (102) being supplied by first and second power supply rails (VDD, VSS) and a second of the inverters (104) being supplied by third and fourth supply rails (114, 116), an input of the second inverter (102) being coupled to a first bit line (BL, WBL) via a first transistor (118); and a power supply circuit (120) adapted to apply a first voltage difference (VDD) across the first and second power supply rails (VDD, VSS) and a second voltage difference (VDH, VSL) across the third and fourth power supply rails (114, 116), the second voltage difference being greater than the first voltage difference.
    Type: Application
    Filed: May 20, 2016
    Publication date: December 22, 2016
    Inventors: Amara AMARA, Kiyoo ITOH, Khaja Ahmad SHAIK
  • Patent number: 8964478
    Abstract: A semiconductor device includes a sense amplifier circuit. The sense amplifier circuit includes a cross-coupled first transistor and second transistor that perform amplification. The sources of the cross-coupled transistors are respectively connected in series with a third transistor and a fourth transistor, and electrical current supply capability of the third and fourth transistors is controlled by a control voltage given to control electrodes of the third and fourth transistors. In a data retaining period, a minimum sub-threshold current necessary for retaining the data is flowed to the third and fourth transistors according to the control voltage, and bit line potential is maintained.
    Type: Grant
    Filed: May 23, 2013
    Date of Patent: February 24, 2015
    Assignee: PS4 Luxco S.a.r.l.
    Inventors: Shinichi Takayama, Akira Kotabe, Kiyoo Itoh, Tomonori Sekiguchi
  • Patent number: 8750032
    Abstract: The disclosed semiconductor recording device achieves multi-valued reading and writing using a spin-injection magnetization-reversal tunneling magnetoresistive element (TMR element). A first current that has at least the same value as that of the element requiring the highest current to reverse the magnetization thereof among a plurality of TMR elements is, in the direction that causes reversal to either a parallel state or an anti-parallel state, applied to a memory cell having the plurality of TMR elements, and then a second current which is in the reverse direction from the first current and of which only the value needed to reverse the magnetoresistance state of at least one TMR element excluding the element requiring the maximum current among the plurality of TMR elements is applied to each, and multi-valued writing is performed.
    Type: Grant
    Filed: April 5, 2011
    Date of Patent: June 10, 2014
    Assignee: Hitachi, Ltd.
    Inventors: Takayuki Kawahara, Riichiro Takemura, Takashi Ishigaki, Kiyoo Itoh
  • Patent number: 8552796
    Abstract: A CMOS circuit and a semiconductor device having small leakage current and a low threshold voltage, and which is operated at high speed and with a small voltage amplitude, including an output stage circuit having MOSTs configured such that when their gates and sources are respectively set to an equal voltage, subthreshold leakage currents substantially flow between their drains and sources, and upon deactivation, a voltage is applied to the gate of each of the MOSTs to cause a reverse bias to be applied between the gate and source of the MOST. Upon activation of the circuit, the MOST is held in a reverse bias state or controlled to a forward bias state according to an input voltage.
    Type: Grant
    Filed: September 12, 2012
    Date of Patent: October 8, 2013
    Assignee: Renesas Electronics Corporation
    Inventors: Kiyoo Itoh, Masanao Yamaoka
  • Publication number: 20130258793
    Abstract: A semiconductor device includes a sense amplifier circuit. The sense amplifier circuit includes a cross-coupled first transistor and second transistor that perform amplification. The sources of the cross-coupled transistors are respectively connected in series with a third transistor and a fourth transistor, and electrical current supply capability of the third and fourth transistors is controlled by a control voltage given to control electrodes of the third and fourth transistors. In a data retaining period, a minimum sub-threshold current necessary for retaining the data is flowed to the third and fourth transistors according to the control voltage, and bit line potential is maintained.
    Type: Application
    Filed: May 23, 2013
    Publication date: October 3, 2013
    Applicant: ELPIDA MEMORY, INC.
    Inventors: Shinichi TAKAYAMA, Akira KOTABE, Kiyoo ITOH, Tomonori SEKIGUCHI
  • Patent number: 8472273
    Abstract: A semiconductor device includes a sense amplifier circuit. The sense amplifier circuit includes a cross-coupled first transistor and second transistor that perform amplification. The sources of the cross-coupled transistors are respectively connected in series with a third transistor and a fourth transistor, and electrical current supply capability of the third and fourth transistors is controlled by a control voltage given to control electrodes of the third and fourth transistors. In a data retaining period, a minimum sub-threshold current necessary for retaining the data is flowed to the third and fourth transistors according to the control voltage, and bit line potential is maintained.
    Type: Grant
    Filed: May 27, 2011
    Date of Patent: June 25, 2013
    Assignee: Elpida Memory, Inc.
    Inventors: Shinichi Takayama, Akira Kotabe, Kiyoo Itoh, Tomonori Sekiguchi
  • Patent number: 8427864
    Abstract: To write information on a memory cell of SPRAM formed of an MOS transistor and a tunnel magnetoresistive element, the memory cell is supplied with a current in a direction opposite to a direction of a current required for writing the information on the memory cell, and then, the memory cell is supplied with a current required for writing. In this manner, even when the same information is sequentially written on the memory cell, since the currents in the two directions are caused to flow in pairs in the tunnel magnetoresistive element of the memory cell each time information is rewritten, deterioration of a film that forms the tunnel magnetoresistive element can be suppressed. Therefore, reliability of the SPRAM can be improved.
    Type: Grant
    Filed: June 2, 2010
    Date of Patent: April 23, 2013
    Assignee: Hitachi, Ltd.
    Inventors: Takayuki Kawahara, Kiyoo Itoh, Riichiro Takemura, Kenchi Ito
  • Publication number: 20130063200
    Abstract: A CMOS circuit and a semiconductor device having small leakage current and a low threshold voltage, and which is operated at high speed and with a small voltage amplitude, including an output stage circuit having MOSTs configured such that when their gates and sources are respectively set to an equal voltage, subthreshold leakage currents substantially flow between their drains and sources, and upon deactivation, a voltage is applied to the gate of each of the MOSTs to cause a reverse bias to be applied between the gate and source of the MOST. Upon activation of the circuit, the MOST is held in a reverse bias state or controlled to a forward bias state according to an input voltage.
    Type: Application
    Filed: September 12, 2012
    Publication date: March 14, 2013
    Inventors: Kiyoo Itoh, Masanao Yamaoka
  • Publication number: 20130051134
    Abstract: The disclosed semiconductor recording device achieves multi-valued reading and writing using a spin-injection magnetization-reversal tunneling magnetoresistive element (TMR element). A first current that has at least the same value as that of the element requiring the highest current to reverse the magnetization thereof among a plurality of TMR elements is, in the direction that causes reversal to either a parallel state or an anti-parallel state, applied to a memory cell having the plurality of TMR elements, and then a second current which is in the reverse direction from the first current and of which only the value needed to reverse the magnetoresistance state of at least one TMR element excluding the element requiring the maximum current among the plurality of TMR elements is applied to each, and multi-valued writing is performed.
    Type: Application
    Filed: April 5, 2011
    Publication date: February 28, 2013
    Inventors: Takayuki Kawahara, Riichiro Takemura, Takashi Ishigaki, Kiyoo Itoh
  • Patent number: 8325553
    Abstract: A static memory cell, composed of cross-coupled MOS transistors having a relatively high threshold voltage, is equipped with MOS transistors for controlling the power supply line voltage of the memory cell. To permit the voltage difference between two data storage nodes in the inactivated memory cell to exceed the voltage difference between the two nodes when write data is applied from a data line pair DL and /DL to the two nodes in the activated memory cell, the power supply line voltage control transistors are turned on to apply a high voltage VCH to the power supply lines after the word line voltage is turned off. The data holding voltage in the memory cell can be activated to a high voltage independent of the data line voltage, and the data holding voltage can be dynamically set so that read and write operations can be performed at high speed with low power consumption.
    Type: Grant
    Filed: June 7, 2011
    Date of Patent: December 4, 2012
    Assignee: Renesas Electronics Corporation
    Inventors: Kiyoo Itoh, Koichiro Ishibashi
  • Patent number: 8294510
    Abstract: There is provided an output stage circuit including such MOSTs (M) that when their gates and sources are respectively set to an equal voltage, subthreshold leakage currents substantially flow between their drains and sources, wherein upon its deactivation, a voltage is applied to the gate of each of the MOSTs (M) in such a manner than a reverse bias is applied between the gate and source of the MOST (M). That is, when the MOST (M) is of a p channel type, a voltage higher than that of a p type source is applied to its gate. When the MOST (M) is of an n channel type, a voltage lower than that of an n type source is applied to its gate. Upon activation of the circuit, the MOST is held in a reverse bias state or controlled to a forward bias state according to an input voltage. A CMOS circuit and a semiconductor device can be realized each of which is small in leakage current even though its threshold voltage is low and which is operated at high speed and with a small voltage amplitude.
    Type: Grant
    Filed: December 11, 2007
    Date of Patent: October 23, 2012
    Assignee: Renesas Electronics Corporation
    Inventors: Kiyoo Itoh, Masanao Yamaoka
  • Publication number: 20120081952
    Abstract: To write information on a memory cell of SPRAM formed of an MOS transistor and a tunnel magnetoresistive element, the memory cell is supplied with a current in a direction opposite to a direction of a current required for writing the information on the memory cell, and then, the memory cell is supplied with a current required for writing. In this manner, even when the same information is sequentially written on the memory cell, since the currents in the two directions are caused to flow in pairs in the tunnel magnetoresistive element of the memory cell each time information is rewritten, deterioration of a film that forms the tunnel magnetoresistive element can be suppressed. Therefore, reliability of the SPRAM can be improved.
    Type: Application
    Filed: June 2, 2010
    Publication date: April 5, 2012
    Inventors: Takayuki Kawahara, Kiyoo Itoh, Riichiro Takemura, Kenchi Ito
  • Patent number: 8106678
    Abstract: A semiconductor device including first and second power lines, and first and second circuit blocks coupled between the power lines. A first switching element is inserted between the first circuit block and at least one of the power lines and a second switching element is inserted between the second circuit block and at least one of the power lines. The first switching element is rendered conductive to allow the first circuit block to receive the power voltage through the first and second power lines while the second switching element is rendered nonconductive to prevent the second circuit block from receiving the power voltage through the first and second power lines, so that a leakage current flowing through the second circuit is suppressed.
    Type: Grant
    Filed: December 23, 2009
    Date of Patent: January 31, 2012
    Assignee: Elpida Memory, Inc.
    Inventors: Takeshi Sakata, Kiyoo Itoh, Masashi Horiguchi
  • Publication number: 20110292709
    Abstract: A semiconductor device includes a sense amplifier circuit. The sense amplifier circuit includes a cross-coupled first transistor and second transistor that perform amplification. The sources of the cross-coupled transistors are respectively connected in series with a third transistor and a fourth transistor, and electrical current supply capability of the third and fourth transistors is controlled by a control voltage given to control electrodes of the third and fourth transistors. In a data retaining period, a minimum sub-threshold current necessary for retaining the data is flowed to the third and fourth transistors according to the control voltage, and bit line potential is maintained.
    Type: Application
    Filed: May 27, 2011
    Publication date: December 1, 2011
    Applicant: ELPIDA MEMORY, INC.
    Inventors: Shinichi TAKAYAMA, Akira KOTABE, Kiyoo ITOH, Tomonori SEKIGUCHI
  • Patent number: 8035147
    Abstract: A high-speed and low-voltage DRAM memory cell capable of operating at 1 V or less and an array peripheral circuit are provided. A DRAM cell is comprised of a memory cell transistor and planar capacitor which utilize a FD-SOI MOST structure. Since there is no junction leakage current, loss of stored charge is eliminated, and the low-voltage operation can be realized. Further, a gate and a well in a cross-coupled type sense amplifier using FD-SOI MOSTs are connected. By this means, a threshold value dynamically changes and high-speed sensing operation can be realized.
    Type: Grant
    Filed: April 27, 2010
    Date of Patent: October 11, 2011
    Assignee: Hitachi, Ltd.
    Inventors: Kiyoo Itoh, Riichiro Takemura
  • Publication number: 20110235439
    Abstract: A static memory cell, composed of cross-coupled MOS transistors having a relatively high threshold voltage, is equipped with MOS transistors for controlling the power supply line voltage of the memory cell. To permit the voltage difference between two data storage nodes in the inactivated memory cell to exceed the voltage difference between the two nodes when write data is applied from a data line pair DL and /DL to the two nodes in the activated memory cell, the power supply line voltage control transistors are turned on to apply a high voltage VCH to the power supply lines after the word line voltage is turned off. The data holding voltage in the memory cell can be activated to a high voltage independent of the data line voltage, and the data holding voltage can be dynamically set so that read and write operations can be performed at high speed with low power consumption.
    Type: Application
    Filed: June 7, 2011
    Publication date: September 29, 2011
    Applicant: RENESAS ELECTRONICS CORPORATION
    Inventors: Kiyoo Itoh, Koichiro Ishibashi
  • Patent number: 7990208
    Abstract: In a semiconductor integrated circuit device, a circuit block has a first MOS transistor, and a leakage current control circuit having a second MOS transistor and a current source, a source and drain circuit of the second MOS transistor is formed between the power supply line of the circuit block and a voltage point where operating voltage is supplied. This current source is connected to the power supply line and in a first state, the power supply line is driven to a first voltage by the second MOS transistor. In a second state, the power supply line is controlled at a second voltage by current flow in the current source and, the voltage applied across the source and drain of the first MOS transistor in the second state is smaller than the voltage applied across the source and drain of the first MOS transistor in the first state.
    Type: Grant
    Filed: November 10, 2009
    Date of Patent: August 2, 2011
    Assignee: Renesas Electronics Corporation
    Inventors: Hiroyuki Mizuno, Kiyoo Itoh