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: 7498637
    Abstract: A SRAM memory is composed of FD-SOI transistors, and performance of the memory cell is improved by controlling an electric potential of a layer under a buried oxide film of a SOI transistor constituting a driver transistor. Performance of the SRAM circuit in the low power voltage state is improved. In the SRAM memory cell composed of the FD-SOI transistor, an electric potential of a well under a BOX layer is controlled to control a threshold voltage Vth, thereby increasing a current. Thus, the operations of the memory cell can be stabilized.
    Type: Grant
    Filed: June 14, 2005
    Date of Patent: March 3, 2009
    Assignee: Renesas Technology Corp.
    Inventors: Masanao Yamaoka, Kenichi Osada, Kiyoo Itoh, Takayuki Kawahara
  • Publication number: 20090003105
    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: Application
    Filed: June 26, 2007
    Publication date: January 1, 2009
    Inventors: Kiyoo ITOH, Riichiro Takemura
  • Publication number: 20080309369
    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: Application
    Filed: June 5, 2008
    Publication date: December 18, 2008
    Inventors: Takeshi SAKATA, Kiyoo ITOH, Masashi HORIGUCHI
  • Patent number: 7443721
    Abstract: A semiconductor non volatile memory device capable of multiple write operations with high reliability includes memory cells. Each memory cell of the device has a first electrode, a second electrode, and an information storage section between the two electrodes. A segregation of composing elements of the information storage section caused by applying a first current pulse from the first electrode to the second electrode is corrected by applying a second current pulse from the second electrode to the first electrode such that the composition of the storage section recovers to its original state.
    Type: Grant
    Filed: January 30, 2006
    Date of Patent: October 28, 2008
    Assignee: Renesas Technology Corp.
    Inventors: Kenzo Kurotsuchi, Kiyoo Itoh, Norikatsu Takaura, Kenichi Osada
  • Patent number: 7388400
    Abstract: A semiconductor integrated circuit with an operating voltage having an absolute value is 2.5 V or below includes circuit blocks to which operation voltage is supplied by first and second power lines and a first switching element for each circuit block. Each circuit block includes a first MOS transistor in which a leakage current flows even under a condition that a gate voltage is equal to a source voltage. Each of the first switching elements controls the leakage current flowing through a corresponding first MOS transistor of each circuit block. Also, while one of the first switching elements is controlled to reduce the leakage current flowing through the circuit block relating to one of the first switching elements, another one of the first switching elements is controlled to allow current to flow through the circuit block relating to another one of the first switching elements.
    Type: Grant
    Filed: June 27, 2007
    Date of Patent: June 17, 2008
    Assignee: Elpida Memory, Inc.
    Inventors: Takeshi Sakata, Kiyoo Itoh, Masashi Horiguchi
  • Patent number: 7385436
    Abstract: A CMOS circuit in low-voltage implementation, low power-consumption implementation, high-speed implementation, or small-size implementation. In a circuit which uses a FD-SOI MOST where a back gate is controlled by a well, voltage amplitude at the well is made larger than input-voltage amplitude at the gate. Alternatively, the circuit is modified into a circuit which uses a MOST that changes dynamically into an enhancement mode and a depletion mode.
    Type: Grant
    Filed: March 7, 2007
    Date of Patent: June 10, 2008
    Assignee: Hitachi, Ltd.
    Inventors: Kiyoo Itoh, Ryuta Tsuchiya, Takayuki Kawahara
  • Publication number: 20080121860
    Abstract: A semiconductor memory cell and forming method thereof utilizes a vertical select transistor to eliminate the problem of a large cell surface area in memory cells of the related art utilizing phase changes. A memory cell with a smaller surface area than the DRAM device of the related art is achieved by the present invention. Besides low power consumption during read operation, the invention also provides phase change memory having low power consumption even during write operation. Phase change memory also has stable read-out operation.
    Type: Application
    Filed: January 16, 2008
    Publication date: May 29, 2008
    Inventors: Hideyuki Matsuoka, Kiyoo Itoh, Motoyasu Terao, Satoru Hanzawa, Takeshi Sakata
  • Patent number: 7379328
    Abstract: Memory blocks having memory cells which are comprised of vertical transistors and memory elements in which the resistance value is varied depending on the temperature imposed on the upper side thereof, are laminated to realize a highly-integrated non-volatile memory.
    Type: Grant
    Filed: June 20, 2007
    Date of Patent: May 27, 2008
    Assignee: Hitachi, Ltd.
    Inventors: Kenichi Osada, Kiyoo Itoh
  • Publication number: 20080072085
    Abstract: A semiconductor integrated circuit device is composed of logic gates each provided with at least two MOS transistors. The logic gates are connected to a first potential point and a second potential point. The semiconductor integrated circuit device includes a current control device connected between the logic gate and the first potential point and/or between the logic gate and the second potential point for controlling a value of a current flowing in the logic gate depending on an operating state of the logic gate. The circuit can be used in devices that cycle in operation between high and low power consumption modes, such as microprocessors that have both an operation mode and a low power back-up or sleep mode used for power reduction.
    Type: Application
    Filed: October 31, 2007
    Publication date: March 20, 2008
    Inventors: Masashi Horiguchi, Kunio Uchiyama, Kiyoo Itoh, Takeshi Sakata, Masakazu Aoki, Takayuki Kawahara
  • Patent number: 7345938
    Abstract: A sense amplifier capable of performing high-speed data sense operation with lower power consumption using a minuscule signal from a memory cell even in a case where a memory array voltage is reduced. A plurality of drive switches for over-driving are distributively arranged in a sense amplifier area, and a plurality of drive switches for restore operation are concentratively disposed at one end of a row of the sense amplifiers. A potential for over-driving is supplied using a meshed power line circuit. Through the use of the drive switches for over-driving, initial sense operation can be performed on data line pairs with a voltage having an amplitude larger than a data-line amplitude, allowing implementation of high-speed sense operation. The distributed arrangement of the drive switched for over-driving makes it possible to dispersively supply current in sense operation, thereby reducing a difference in sense voltage with respect to far and near positions of the sense amplifiers.
    Type: Grant
    Filed: May 9, 2007
    Date of Patent: March 18, 2008
    Assignee: Renesas Technology Corp.
    Inventors: Riichiro Takemura, Kiyoo Itoh, Tomonori Sekiguchi, Takeshi Sakata, Katsutaka Kimura
  • Publication number: 20080062736
    Abstract: The object of the invention is to avoid an unselected data line being driven in a memory array composed of memory cells each of which uses a storage element depending upon variable resistance and a selection transistor when the selection transistors in all memory cells on a selected wordline conduct. To achieve the object, a source line parallel to a data line is provided, a precharge circuit for equipotentially driving both and a circuit for selectively driving the source line are arranged. Owing to this configuration, a current path is created in only a cell selected by a row decoder and a column decoder and a read-out signal can be generated. Therefore, a lower-power, lower-noise and more highly integrated nonvolatile memory such as a phase change memory can be realized, compared with a conventional type.
    Type: Application
    Filed: October 25, 2007
    Publication date: March 13, 2008
    Inventors: Satoru Hanzawa, Kiyoo Itoh, Hideyuki Matsuoka, Motoyasu Terao, Takeshi Sakata
  • Patent number: 7341892
    Abstract: A semiconductor memory cell and forming method thereof utilizes a vertical select transistor to eliminate the problem of a large cell surface area in memory cells of the related art utilizing phase changes. A memory cell with a smaller surface area than the DRAM device of the related art is achieved by the present invention. Besides low power consumption during read operation, the invention also provides phase change memory having low power consumption even during write operation. Phase change memory also has stable read-out operation.
    Type: Grant
    Filed: March 7, 2006
    Date of Patent: March 11, 2008
    Assignee: Hitachi, Ltd.
    Inventors: Hideyuki Matsuoka, Kiyoo Itoh, Motoyasu Terao, Satoru Hanzawa, Takeshi Sakata
  • Patent number: 7324372
    Abstract: The object of the invention is to avoid an unselected data line being driven in a memory array composed of memory cells each of which uses a storage element depending upon variable resistance and a selection transistor when the selection transistors in all memory cells on a selected word line conduct. To achieve the object, a source line parallel to a data line is provided, a precharge circuit for equipotentially driving both and a circuit for selectively driving the source line are arranged. Owing to this configuration, a current path is created in only a cell selected by a row decoder and a column decoder and a read-out signal can be generated. Therefore, a lower-power, lower-noise and more highly integrated nonvolatile memory such as a phase change memory can be realized, compared with a conventional type.
    Type: Grant
    Filed: August 22, 2006
    Date of Patent: January 29, 2008
    Assignee: Hitachi, Ltd.
    Inventors: Satoru Hanzawa, Kiyoo Itoh, Hideyuki Matsuoka, Motoyasu Terao, Takeshi Sakata
  • Patent number: 7312640
    Abstract: A semiconductor integrated circuit device is composed of logic gates each provided with at least two MOS transistors. The logic gates are connected to a first potential point and a second potential point. The semiconductor integrated circuit device includes a current control device connected between the logic gate and the first potential point and/or between the logic gate and the second potential point for controlling a value of a current flowing in the logic gate depending on an operating state of the logic gate. The circuit can be used in devices that cycle in operation between high and low power consumption modes, such as microprocessors that have both an operation mode and a low power back-up or sleep mode used for power reduction.
    Type: Grant
    Filed: May 18, 2005
    Date of Patent: December 25, 2007
    Assignee: Renesas Technology Corp.
    Inventors: Masashi Horiguchi, Kunio Uchiyama, Kiyoo Itoh, Takeshi Sakata, Masakazu Aoki, Takayuki Kawahara
  • Publication number: 20070263433
    Abstract: Memory blocks having memory cells which are comprised of vertical transistors and memory elements in which the resistance value is varied depending on the temperature imposed on the upper side thereof, are laminated to realize a highly-integrated non-volatile memory.
    Type: Application
    Filed: June 20, 2007
    Publication date: November 15, 2007
    Inventors: Kenichi Osada, Kiyoo Itoh
  • Publication number: 20070247186
    Abstract: A semiconductor integrated circuit with an operating voltage having an absolute value is 2.5 V or below includes circuit blocks to which operation voltage is supplied by first and second power lines and a first switching element for each circuit block. Each circuit block includes a first MOS transistor in which a leakage current flows even under a condition that a gate voltage is equal to a source voltage. Each of the first switching elements controls the leakage current flowing through a corresponding first MOS transistor of each circuit block. Also, while one of the first switching elements is controlled to reduce the leakage current flowing through the circuit block relating to one of the first switching elements, another one of the first switching elements is controlled to allow current to flow through the circuit block relating to another one of the first switching elements.
    Type: Application
    Filed: June 27, 2007
    Publication date: October 25, 2007
    Inventors: Takeshi SAKATA, Kiyoo Itoh, Masashi Horiguchi
  • Publication number: 20070211547
    Abstract: A sense amplifier capable of performing high-speed data sense operation with lower power consumption using a minuscule signal from a memory cell even in a case where a memory array voltage is reduced. A plurality of drive switches for over-driving are distributively arranged in a sense amplifier area, and a plurality of drive switches for restore operation are concentratively disposed at one end of a row of the sense amplifiers. A potential for over-driving is supplied using a meshed power line circuit. Through the use of the drive switches for over-driving, initial sense operation can be performed on data line pairs with a voltage having an amplitude larger than a data-line amplitude, allowing implementation of high-speed sense operation. The distributed arrangement of the drive switched for over-driving makes it possible to dispersively supply current in sense operation, thereby reducing a difference in sense voltage with respect to far and near positions of the sense amplifiers.
    Type: Application
    Filed: May 9, 2007
    Publication date: September 13, 2007
    Inventors: Riichiro Takemura, Kiyoo Itoh, Tomonori Sekiguchi, Takeshi Sakata, Katsutaka Kimura
  • Patent number: 7251157
    Abstract: Memory blocks having memory cells which are comprised of vertical transistors and memory elements in which the resistance value is varied depending on the temperature imposed on the upper side thereof, are laminated to realize a highly-integrated non-volatile memory.
    Type: Grant
    Filed: September 3, 2004
    Date of Patent: July 31, 2007
    Assignee: Hitachi, Ltd.
    Inventors: Kenichi Osada, Kiyoo Itoh
  • Patent number: 7251183
    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 9, 2005
    Date of Patent: July 31, 2007
    Assignee: Hitachi, Ltd.
    Inventors: Kiyoo Itoh, Koichiro Ishibashi
  • Publication number: 20070165448
    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: March 15, 2007
    Publication date: July 19, 2007
    Inventors: Kiyoo Itoh, Koichiro Ishibashi