Patents by Inventor Shuichi Tsukada

Shuichi Tsukada 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: 20150228325
    Abstract: The semiconductor device includes: a word line; a bit line: a power supply node; a plurality of memory elements including at least first and second regions that form a PN junction between the bit line, and the power supply node, and a third region that forms a PN junction with the second region; and a control circuit which, during a refresh operation, activates both a used word line that is accessed during reading and writing operations and an unused. word line that is not accessed during the reading and writing operations, and sets a potential of the second region of each of the used word line and the unused word line at a predetermined voltage.
    Type: Application
    Filed: August 23, 2013
    Publication date: August 13, 2015
    Inventors: Shuichi Tsukada, Yasuko Hattori, Natsuki Sato
  • Publication number: 20150085561
    Abstract: A semiconductor device includes a memory cell array including a plurality of first and second memory cells each comprising a variable resistance element that establishes an electrical resistance that changes in response to an application of a write voltage after a forming voltage has been applied, the first memory cell to which the forming voltage is applied, and the second memory cell to which the forming voltage is not applied, and the second memory cell being configured to store one of first and second logic values constituting first information, the first and second logic values being different from each other.
    Type: Application
    Filed: September 24, 2014
    Publication date: March 26, 2015
    Inventors: Akiko Maeda, Shuichi Tsukada, Yusuke Jono
  • Publication number: 20150063003
    Abstract: A semiconductor device including: a resistive memory element; a data line electrically coupled to the resistive memory element; a control line; a power supply line; and a control circuit including a first constant current element, a first transistor, and a second transistor. In the control circuit, the first transistor has a gate coupled to the data line, one of a source and a drain coupled to the first constant current element, and the other one of the source and the drain coupled to the power supply line. The second transistor has a gate coupled to one of the source and the drain of the first transistor, one of a source and a drain coupled to the data line, and the other one of the source and the drain coupled to the control line.
    Type: Application
    Filed: August 29, 2014
    Publication date: March 5, 2015
    Inventor: Shuichi Tsukada
  • Patent number: 8879312
    Abstract: A supply voltage generating circuit includes a first charge pump circuit that generates a first internal supply voltage, and second charge pump circuit that generates a second internal supply voltage. The absolute value of the second internal supply voltage is greater than that of the first internal supply voltage. The output terminal of the first charge pump circuit is connected to a secondary-side charging terminal of the second charge pump circuit. The secondary-side is an output-side of the corresponding charge pump circuit, and the charging terminal is an auxiliary charging terminal that supplies an auxiliary charge to a secondary-side output terminal of the corresponding charge pump circuit. The output terminal of the second charge pump circuit outputs a voltage value that is the result of adding a prescribed voltage value to the value of the first internal supply voltage applied to the charging terminal.
    Type: Grant
    Filed: March 10, 2014
    Date of Patent: November 4, 2014
    Assignee: PS4 Luxco S.a.r.l.
    Inventor: Shuichi Tsukada
  • Publication number: 20140247651
    Abstract: A semiconductor device includes a word line, a bit line, a power supply node, a memory element that includes at least first and second regions that form a PN junction between the bit lie and the power supply node, and a third region that forms a PN junction with the second region and a capacitor that includes a first electrode provided independently from the second region of the memory element and electrically connected to the second region of the memory element, and a second electrode connected to the word line.
    Type: Application
    Filed: May 12, 2014
    Publication date: September 4, 2014
    Inventors: Shuichi Tsukada, Yasuhiro Uchiyama
  • Publication number: 20140185373
    Abstract: A supply voltage generating circuit includes a first charge pump circuit that generates a first internal supply voltage, and second charge pump circuit that generates a second internal supply voltage. The absolute value of the second internal supply voltage is greater than that of the first internal supply voltage. The output terminal of the first charge pump circuit is connected to a secondary-side charging terminal of the second charge pump circuit. The secondary-side is an output-side of the corresponding charge pump circuit, and the charging terminal is an auxiliary charging terminal that supplies an auxiliary charge to a secondary-side output terminal of the corresponding charge pump circuit. The output terminal of the second charge pump circuit outputs a voltage value that is the result of adding a prescribed voltage value to the value of the first internal supply voltage applied to the charging terminal.
    Type: Application
    Filed: March 10, 2014
    Publication date: July 3, 2014
    Inventor: Shuichi TSUKADA
  • Patent number: 8737124
    Abstract: There is provided a semiconductor device including a word line, a bit line, a power supply node, a memory element, and a capacitor. The memory element includes at least first and second regions that form a PN junction between the bit line and the power supply node, and a third region that forms a PN junction with the second region. The capacitor includes a first electrode provided independently from the second region of the memory element and electrically connected to the second region of the memory element, and a second electrode connected to the word line.
    Type: Grant
    Filed: April 26, 2012
    Date of Patent: May 27, 2014
    Inventors: Shuichi Tsukada, Yasuhiro Uchiyama
  • Patent number: 8711611
    Abstract: A supply voltage generating circuit includes a first charge pump circuit that generates a first internal supply voltage, and second charge pump circuit that generates a second internal supply voltage. The absolute value of the second internal supply voltage is greater than that of the first internal supply voltage. The output terminal of the first charge pump circuit is connected to a secondary-side charging terminal of the second charge pump circuit. The secondary-side is an output-side of the corresponding charge pump circuit, and the charging terminal is an auxiliary charging terminal that supplies an auxiliary charge to a secondary-side output terminal of the corresponding charge pump circuit. The output terminal of the second charge pump circuit outputs a voltage value that is the result of adding a prescribed voltage value to the value of the first internal supply voltage applied to the charging terminal.
    Type: Grant
    Filed: March 18, 2013
    Date of Patent: April 29, 2014
    Inventor: Shuichi Tsukada
  • Patent number: 8503253
    Abstract: A supply voltage generating circuit includes a first charge pump circuit that generates a first internal supply voltage, and second charge pump circuit that generates a second internal supply voltage. The absolute value of the second internal supply voltage is greater than that of the first internal supply voltage. The output terminal of the first charge pump circuit is connected to a secondary-side charging terminal of the second charge pump circuit. The secondary-side is an output-side of the corresponding charge pump circuit, and the charging terminal is an auxiliary charging terminal that supplies an auxiliary charge to a secondary-side output terminal of the corresponding charge pump circuit. The output terminal of the second charge pump circuit outputs a voltage value that is the result of adding a prescribed voltage value to the value of the first internal supply voltage applied to the charging terminal.
    Type: Grant
    Filed: October 9, 2012
    Date of Patent: August 6, 2013
    Assignee: Elpida Memory, Inc.
    Inventor: Shuichi Tsukada
  • Patent number: 8462538
    Abstract: A semiconductor device includes a plurality of drain lines each being commonly connected to first nodes of a plurality of memory cells, a plurality of bit lines respectively connected to second nodes of the memory cells, a source line, a transistor that connects the drain lines to the source line, and a transistor that connects the source line to a ground potential in response to an access to the memory cell. Under control in which the memory cells are all deactivated, the semiconductor device controls the drain line to a drain potential that is higher than the ground potential, and controls the source line to be in a floating state by deactivating the transistors.
    Type: Grant
    Filed: March 9, 2011
    Date of Patent: June 11, 2013
    Assignee: Elpida Memory, Inc.
    Inventor: Shuichi Tsukada
  • Patent number: 8389969
    Abstract: A semiconductor device includes a semiconductor substrate of a first conductivity type, a first insulating film region that is embedded in a trench formed on the semiconductor substrate, a gate electrode that covers a lower surface of the first insulating film region, and a gate insulating film that is provided between the gate electrode and the semiconductor substrate. The semiconductor device further includes a first diffusion region that covers a first side surface of the first insulating film region, a second diffusion region that covers a second side surface of the first insulating film region, and a third diffusion region that covers an upper surface of the second diffusion region. A selective element includes a field-effect transistor that is constituted by the gate electrode, the first diffusion region, and the second diffusion region, and a bipolar transistor that is constituted by the substrate and the second and third diffusion regions.
    Type: Grant
    Filed: February 17, 2011
    Date of Patent: March 5, 2013
    Assignee: Elpida Memory, Inc.
    Inventors: Shuichi Tsukada, Yasuhiro Uchiyama
  • Publication number: 20130033930
    Abstract: A supply voltage generating circuit includes a first charge pump circuit that generates a first internal supply voltage, and second charge pump circuit that generates a second internal supply voltage. The absolute value of the second internal supply voltage is greater than that of the first internal supply voltage. The output terminal of the first charge pump circuit is connected to a secondary-side charging terminal of the second charge pump circuit. The secondary-side is an output-side of the corresponding charge pump circuit, and the charging terminal is an auxiliary charging terminal that supplies an auxiliary charge to a secondary-side output terminal of the corresponding charge pump circuit. The output terminal of the second charge pump circuit outputs a voltage value that is the result of adding a prescribed voltage value to the value of the first internal supply voltage applied to the charging terminal.
    Type: Application
    Filed: October 9, 2012
    Publication date: February 7, 2013
    Applicant: ELPIDA MEMORY, INC.
    Inventor: Shuichi TSUKADA
  • Patent number: 8354877
    Abstract: A current limit circuit comprising: a current limit element for limiting an output current level to within a predetermined range of a limiting current and including a first PMOS transistor having a source to which a predetermined voltage is applied and a drain through which the output current is supplied; and a gate voltage generating circuit for generating a gate voltage by a feedback control such that a difference between the predetermined voltage and a gate voltage of the first PMOS transistor coincides with a threshold voltage of a second PMOS transistor having approximately the same characteristic as that of the first PMOS transistor in a state in which a predetermined current is flowing through the second PMOS transistor.
    Type: Grant
    Filed: October 27, 2009
    Date of Patent: January 15, 2013
    Assignee: Apple Inc.
    Inventor: Shuichi Tsukada
  • Publication number: 20120314483
    Abstract: A semiconductor device includes a bit line, a memory cell, and a control circuit. The memory cell includes a switch circuit coupled to the bit line and a memory element configured to store either one of first and second data. The control circuit controls a voltage of the bit line to turn on the switch element in a first time period and to turn off the switch element in a second time period following the first time period when the control circuit writes the first data to the memory element. The control circuit controls the voltage of the bit line to turn on the switch element in the first time period and to maintain an on-state of the switch circuit in the second time period when the control circuit writes the second data to the memory element.
    Type: Application
    Filed: May 31, 2012
    Publication date: December 13, 2012
    Applicant: Elpida Memory, Inc.
    Inventor: Shuichi TSUKADA
  • Patent number: 8310865
    Abstract: A semiconductor memory device comprises a memory cell, first and second voltage generating circuits generating first and second voltages, and a control circuit. A memory element and a diode included in the memory cell are connected in series between first and second lines. The first voltage has no temperature dependence, and the second voltage has a temperature dependence opposite to that of a forward voltage of the diode. The control circuit detects a resistance state of the memory element in accordance with a change in current flowing in the memory cell in a state where the first/second voltage is applied to the first/second in a read operation of the memory cell.
    Type: Grant
    Filed: October 6, 2010
    Date of Patent: November 13, 2012
    Assignee: Elpida Memory Inc.
    Inventor: Shuichi Tsukada
  • Patent number: 8305799
    Abstract: A supply voltage generating circuit includes a first charge pump circuit that generates a first internal supply voltage, and second charge pump circuit that generates a second internal supply voltage. The absolute value of the second internal supply voltage is greater than that of the first internal supply voltage. The output terminal of the first charge pump circuit is connected to a secondary-side charging terminal of the second charge pump circuit. The secondary-side is an output-side of the corresponding charge pump circuit, and the charging terminal is an auxiliary charging terminal that supplies an auxiliary charge to a secondary-side output terminal of the corresponding charge pump circuit. The output terminal of the second charge pump circuit outputs a voltage value that is the result of adding a prescribed voltage value to the value of the first internal supply voltage applied to the charging terminal.
    Type: Grant
    Filed: June 3, 2010
    Date of Patent: November 6, 2012
    Assignee: Elpida Memory, Inc.
    Inventor: Shuichi Tsukada
  • Publication number: 20120275215
    Abstract: There is provided a semiconductor device including a word line, a bit line, a power supply node, a memory element, and a capacitor. The memory element includes at least first and second regions that form a PN junction between the bit line and the power supply node, and a third region that forms a PN junction with the second region. The capacitor includes a first electrode provided independently from the second region of the memory element and electrically connected to the second region of the memory element, and a second electrode connected to the word line.
    Type: Application
    Filed: April 26, 2012
    Publication date: November 1, 2012
    Applicant: Elpida Memory, Inc.
    Inventors: Shuichi TSUKADA, Yasuhiro Uchiyama
  • Patent number: 8223536
    Abstract: A semiconductor memory device comprises: a phase change element (RP) and a memory cell transistor (MN0) that controls writing and reading of data with respect to the phase change element (RP); the memory cell transistor (MN0) supplies a current to the phase change element (RP) based on a first potential (VPS) in a first (read) operation mode, and in a second (write) operation mode supplies a current based on the first potential (VPS), and subsequently supplies a current based on a second potential (VPP) higher than the first potential (VPS). In a write operation, consumed current is reduced.
    Type: Grant
    Filed: September 15, 2010
    Date of Patent: July 17, 2012
    Assignee: Elpida Memory, Inc.
    Inventors: Yasuko Tonomura, Shuichi Tsukada
  • Patent number: 8139404
    Abstract: The semiconductor memory device includes a control circuit that performs control of reading data from and writing data into each memory cell. The control circuit includes a flip-flop circuit that stores the data read from the memory cell and stores the data to be written into the memory cell and a dynamic type holding circuit connected to the flip-flop circuit through a switch. The dynamic-type holding circuit temporarily stores the data read from the memory cell. When the data read from the memory cell and then held in the holding circuit is different from the data in the flip-flop circuit to be written, supplied from an outside at a time of writing into the memory cell, control is performed so that the data in the flip-flop circuit is written into the memory cell.
    Type: Grant
    Filed: April 2, 2010
    Date of Patent: March 20, 2012
    Assignee: Elpida Memory, Inc.
    Inventor: Shuichi Tsukada
  • Patent number: 8094483
    Abstract: A semiconductor device includes: a first read/write amplifier; a second read/write amplifier; a first group of bit lines belonging to the first read/write amplifier; a second group of bit lines belonging to the second read/write amplifier and mixed with the first group of bit lines. One of the first group of bit lines and one of the second group of bit lines are selected in parallel. A reference potential is supplied to at least one of the first non-selected bit lines adjacent to the first selected bit line selected from the first group of bit lines, and to at least one of the second non-selected bit lines adjacent to the second selected bit line selected from the first group of bit lines. At least one of remaining ones of the first and second non-selected bit lines is set into a floating state.
    Type: Grant
    Filed: December 1, 2009
    Date of Patent: January 10, 2012
    Assignee: Elpida Memory, Inc.
    Inventors: Kiyoshi Nakai, Shuichi Tsukada