Patents by Inventor Ryuuji Takishita

Ryuuji Takishita 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: 20140225640
    Abstract: To suppress the number of clocks needed to adjust the impedance of an output buffer. A pull-up replica buffer is connected between a calibration terminal and power supply wiring, and is controlled in impedance by a DRZQP signal supplied from a counter. A pull-down replica buffer is connected between ground wiring and a connection node A, and is controlled in impedance by a DRZQN signal supplied from the counter. More specifically, the DRZQP signal and the DRZQN signal indicate count values. The impedances of the replica buffers are increased or decreased stepwise in proportion to the count values. The count values are updated according to a binary search method.
    Type: Application
    Filed: February 21, 2014
    Publication date: August 14, 2014
    Inventors: Koji Kuroki, Daiki Nakashima, Ryuuji Takishita
  • Patent number: 8710861
    Abstract: To suppress the number of clocks needed to adjust the impedance of an output buffer. A pull-up replica buffer is connected between a calibration terminal and power supply wiring, and is controlled in impedance by a DRZQP signal supplied from a counter. A pull-down replica buffer is connected between ground wiring and a connection node A, and is controlled in impedance by a DRZQN signal supplied from the counter. More specifically, the DRZQP signal and the DRZQN signal indicate count values. The impedances of the replica buffers are increased or decreased stepwise in proportion to the count values. The count values are updated according to a binary search method.
    Type: Grant
    Filed: August 26, 2011
    Date of Patent: April 29, 2014
    Assignee: Elpida Memory, Inc.
    Inventors: Koji Kuroki, Daiki Nakashima, Ryuuji Takishita
  • Patent number: 8422326
    Abstract: For example, four driver transistors are arranged in wells so as to adjoin both sides of each of two element isolation regions. Two pairs of cross-coupled sense transistors are arranged in the wells at positions farther from the element isolation regions than the driver transistors are. Such an arrangement provides more than a certain distance between the sense transistors and the respective corresponding element isolation regions. This reduces the effect of a phenomenon that threshold of a transistor varies according to a distance from an element isolation region. As a result, it is possible to exactly match the characteristics of each pair of cross-coupled transistors.
    Type: Grant
    Filed: November 23, 2011
    Date of Patent: April 16, 2013
    Assignee: Elpida Memory, Inc.
    Inventors: Hiroki Fujisawa, Ryuuji Takishita
  • Publication number: 20120134227
    Abstract: For example, four driver transistors are arranged in wells so as to adjoin both sides of each of two element isolation regions. Two pairs of cross-coupled sense transistors are arranged in the wells at positions farther from the element isolation regions than the driver transistors are. Such an arrangement provides more than a certain distance between the sense transistors and the respective corresponding element isolation regions. This reduces the effect of a phenomenon that threshold of a transistor varies according to a distance from an element isolation region. As a result, it is possible to exactly match the characteristics of each pair of cross-coupled transistors.
    Type: Application
    Filed: November 23, 2011
    Publication date: May 31, 2012
    Applicant: Elpida Memory, Inc.
    Inventors: Hiroki FUJISAWA, Ryuuji Takishita
  • Patent number: 8134405
    Abstract: A semiconductor device includes a power-supply control portion and a latch portion. The power-supply control portion supplies power to an internal circuit in response to an input signal synchronized with rising of clock. The latch portion latches the input signal in synchronization with falling of the clock and supplies the latched input signal to the internal circuit.
    Type: Grant
    Filed: October 24, 2008
    Date of Patent: March 13, 2012
    Assignee: Elpida Memory, Inc.
    Inventors: Hideyuki Yoko, Ryuuji Takishita
  • Publication number: 20120056641
    Abstract: To suppress the number of clocks needed to adjust the impedance of an output buffer. A pull-up replica buffer is connected between a calibration terminal and power supply wiring, and is controlled in impedance by a DRZQP signal supplied from a counter. A pull-down replica buffer is connected between ground wiring and a connection node A, and is controlled in impedance by a DRZQN signal supplied from the counter. More specifically, the DRZQP signal and the DRZQN signal indicate count values. The impedances of the replica buffers are increased or decreased stepwise in proportion to the count values. The count values are updated according to a binary search method.
    Type: Application
    Filed: August 26, 2011
    Publication date: March 8, 2012
    Applicant: ELPIDA MEMORY, INC.
    Inventors: Koji Kuroki, Daiki Nakashima, Ryuuji Takishita
  • Patent number: 8013645
    Abstract: A DLL circuit is designed to adjust the delay time and the duty applied to an input clock signal, thus producing a DLL clock signal. In a non-clocking state of the DLL clock signal in which pulses disappear temporarily, the DLL circuit stops updating the delay time and the duty of the DLL clock signal. That is, the DLL circuit is capable of preventing a phase difference between the input clock signal and the DLL clock signal from being erroneously detected in the non-clocking state of the DLL clock signal, thus preventing the delay time and the duty from being updated based on the erroneously detected phase difference. Thus, it is possible to reduce the number of cycles adapted to the delay-locked control and to thereby stabilize the operation of the DLL circuit.
    Type: Grant
    Filed: May 13, 2009
    Date of Patent: September 6, 2011
    Assignee: Elpida Memory, Inc.
    Inventors: Koji Kuroki, Ryuuji Takishita
  • Publication number: 20090284290
    Abstract: A DLL circuit is designed to adjust the delay time and the duty applied to an input clock signal, thus producing a DLL clock signal. In a non-clocking state of the DLL clock signal in which pulses disappear temporarily, the DLL circuit stops updating the delay time and the duty of the DLL clock signal. That is, the DLL circuit is capable of preventing a phase difference between the input clock signal and the DLL clock signal from being erroneously detected in the non-clocking state of the DLL clock signal, thus preventing the delay time and the duty from being updated based on the erroneously detected phase difference. Thus, it is possible to reduce the number of cycles adapted to the delay-locked control and to thereby stabilize the operation of the DLL circuit.
    Type: Application
    Filed: May 13, 2009
    Publication date: November 19, 2009
    Applicant: ELPIDA MEMORY, INC.
    Inventors: Koji Kuroki, Ryuuji Takishita
  • Publication number: 20090108897
    Abstract: A semiconductor device includes a power-supply control portion and a latch portion. The power-supply control portion supplies power to an internal circuit in response to an input signal synchronized with rising of clock. The latch portion latches the input signal in synchronization with falling of the clock and supplies the latched input signal to the internal circuit.
    Type: Application
    Filed: October 24, 2008
    Publication date: April 30, 2009
    Applicant: ELPIDA MEMORY, INC.,
    Inventors: Hideyuki YOKO, Ryuuji TAKISHITA
  • Patent number: RE45604
    Abstract: A DLL circuit is designed to adjust the delay time and the duty applied to an input clock signal, thus producing a DLL clock signal. In a non-clocking state of the DLL clock signal in which pulses disappear temporarily, the DLL circuit stops updating the delay time and the duty of the DLL clock signal. That is, the DLL circuit is capable of preventing a phase difference between the input clock signal and the DLL clock signal from being erroneously detected in the non-clocking state of the DLL clock signal, thus preventing the delay time and the duty from being updated based on the erroneously detected phase difference. Thus, it is possible to reduce the number of cycles adapted to the delay-locked control and to thereby stabilize the operation of the DLL circuit.
    Type: Grant
    Filed: September 6, 2013
    Date of Patent: July 7, 2015
    Assignee: PS4 LUXCO S.A.R.L.
    Inventors: Koji Kuroki, Ryuuji Takishita
  • Patent number: RE46141
    Abstract: A semiconductor device includes a power-supply control portion and a latch portion. The power-supply control portion supplies power to an internal circuit in response to an input signal synchronized with rising of clock. The latch portion latches the input signal in synchronization with falling of the clock and supplies the latched input signal to the internal circuit.
    Type: Grant
    Filed: March 12, 2014
    Date of Patent: September 6, 2016
    Assignee: PS4 Luxco S.a.r.l.
    Inventors: Hideyuki Yoko, Ryuuji Takishita