Patents by Inventor Yuui Shimizu

Yuui Shimizu 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: 20140286110
    Abstract: A semiconductor memory device comprises: a plurality of on-die termination circuits connected to each of a plurality of input/output pads; and a control circuit for controlling the on-die termination circuit. The on-die termination circuit comprises: a pull-up element connected between a first terminal and an output terminal; and a pull-down element connected between the output terminal and a second terminal. The pull-up element is driven by a first pull-up element driver, and the pull-down element is driven by a first pull-down element driver. The control circuit activates a plurality of the on-die termination circuits at different timings.
    Type: Application
    Filed: September 6, 2013
    Publication date: September 25, 2014
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Yuui SHIMIZU, Yasuhiro Suematsu
  • Publication number: 20140269089
    Abstract: A semiconductor memory device comprises a first-supplied-voltage-supplying pad, a second-supplied-voltage-supplying pad, a data input/output pad, a memory body, a buffer circuit and an impedance-controlling circuit. A first supplied voltage is supplied to the memory body. A second supplied voltage is supplied to the buffer circuit. The impedance-controlling circuit controls an impedance of the buffer circuit on a side connected to the data input/output pad. The semiconductor memory device comprises a voltage-generating circuit generating a first inner voltage. The impedance-controlling circuit comprises a first P-channel transistor. A source terminal of the first P-channel transistor is connected to the first-supplied-voltage-supplying pad, and the first inner voltage generated from the voltage-generating circuit is selectively supplied to a gate terminal of the first P-channel transistor.
    Type: Application
    Filed: September 9, 2013
    Publication date: September 18, 2014
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Yuui SHIMIZU, Satoshi INOUE
  • Publication number: 20140269107
    Abstract: A semiconductor memory device comprises an inner circuit, an output buffer circuit, an output buffer controlling circuit, and a chip operation temperature sensor. The output buffer circuit outputs data from the inner circuit via a data input/output pad. The output buffer controlling circuit controls a driving power of the output buffer circuit. The chip operation temperature sensor detects an operation temperature of a chip of the semiconductor device. The output buffer controlling circuit selects an impedance controlling condition from a plurality of the impedance controlling conditions according to the output signal of the chip operation temperature sensor and controls the output buffer circuit according to the selected impedance controlling condition.
    Type: Application
    Filed: September 11, 2013
    Publication date: September 18, 2014
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Satoshi INOUE, Yuui SHIMIZU
  • Patent number: 8736346
    Abstract: According to one embodiment, a level shift circuit includes a plurality of level shift units which are connected to each other and in which the delay time of the rising edge of an output voltage is different from the delay time of the falling edge of the output voltage. The delay time of the rising edge of the output voltage from the previous level shift unit is compensated by the delay time of the falling edge of the output voltage from the next level shift unit, and the delay time of the falling edge of the output voltage from the previous level shift unit is compensated by the delay time of the rising edge of the output voltage from the next level shift unit.
    Type: Grant
    Filed: June 15, 2012
    Date of Patent: May 27, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yuui Shimizu, Masaru Koyanagi
  • Patent number: 8730757
    Abstract: According to one embodiment, a memory system includes a first semiconductor memory and a controller. The first semiconductor memory receives a first clock, and outputs, in accordance with the first clock, a second clock and a data signal in synchronization with the second clock. The controller includes a detection circuit which detects a shift of a duty ratio of the second clock which is output from the first semiconductor memory. The controller also includes an adjustment circuit which adjusts a duty ratio of the first clock based on the shift detected by the detection circuit.
    Type: Grant
    Filed: September 4, 2012
    Date of Patent: May 20, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Yuui Shimizu
  • Patent number: 8558576
    Abstract: According to one embodiment, a clamp transistor is inserted in series between a P-channel field effect transistor and an N-channel field effect transistor and an intermediate level between a high potential supplied to a source of the P-channel field effect transistor and a low potential supplied to a source of the N-channel field effect transistor is input into a gate of the clamp transistor to clamp a drain potential of the N-channel field effect transistor.
    Type: Grant
    Filed: March 4, 2011
    Date of Patent: October 15, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Yuui Shimizu
  • Publication number: 20130250693
    Abstract: According to one embodiment, a memory system includes a first semiconductor memory and a controller. The first semiconductor memory receives a first clock, and outputs, in accordance with the first clock, a second clock and a data signal in synchronization with the second clock. The controller includes a detection circuit which detects a shift of a duty ratio of the second clock which is output from the first semiconductor memory. The controller also includes an adjustment circuit which adjusts a duty ratio of the first clock based on the shift detected by the detection circuit.
    Type: Application
    Filed: September 4, 2012
    Publication date: September 26, 2013
    Inventor: Yuui SHIMIZU
  • Publication number: 20130242664
    Abstract: According to an embodiment, an interface circuit is provided with an output buffer which generates an output waveform on the basis of the ON/OFF operation of a transistor and a driver circuit which drives the transistor and is capable of independently changing a turn-ON speed and a turn-OFF speed of the transistor.
    Type: Application
    Filed: September 14, 2012
    Publication date: September 19, 2013
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Yuui SHIMIZU, Masaru KOYANAGI, Yasuhiro SUEMATSU
  • Patent number: 8531882
    Abstract: A memory includes stacking chips. The chip includes a pad commonly connected to the chips and receiving an enable signal that enables access to each chip. The chip includes a chip address memory that can store a chip address. The chip includes a determining part comparing a select address to the chip address for determining whether they match each other. The chip includes a control-signal setting part setting the control signal inputted to the chip itself to be valid or invalid depending on a determination made by the determining part. The chip includes a chip-address setting part determining whether the chip address is stored in the chip address memory depending on number of fail bits. The device includes a memory controller allocating respectively different ones of the chip addresses to the chips based on the number of fail bits.
    Type: Grant
    Filed: June 14, 2011
    Date of Patent: September 10, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tomofumi Fujimura, Yuui Shimizu
  • Patent number: 8410811
    Abstract: According to one embodiment, an input circuit includes an input buffer, a control unit, a holding unit, a feedback unit. The input buffer receives a signal input from an outside. The input buffer includes a plurality of CMOS inverters connected in parallel. The plurality of CMOS inverters includes a plurality of PMOS transistors and a plurality of NMOS transistors. The control unit selects one or more PMOS transistors from the plurality of PMOS transistors so as to enter an operable state. The control unit selects one or more NMOS transistors from the plurality of NMOS transistors so as to enter an operable state. The holding unit holds a level of a signal transferred from the input buffer in synchronization with a clock signal. The holding unit outputs the held signal level. The feedback unit feeds the level of the signal output from the holding unit back to the control unit.
    Type: Grant
    Filed: July 27, 2011
    Date of Patent: April 2, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Yuui Shimizu
  • Patent number: 8391040
    Abstract: According to one embodiment, a nonvolatile semiconductor memory device includes a first memory chip, a second memory chip, and a control chip. The first chip includes a first inductor configured to transmit/receive a signal, and a memory cell. The second chip is disposed on the first chip and includes a second inductor configured to transmit/receive a signal, and a memory cell. The control chip includes a control circuit configured to control the first and second chips, and a third inductor configured to transmit/receive a signal to/from the first and second inductors. The outer peripheries of the first and second inductors are included in a closed space produced by extending the outer periphery of the third inductor in a direction perpendicular to a plane that includes the third inductor. The inductance of the third inductor is greater than at least one of the inductances of the first and second inductors.
    Type: Grant
    Filed: March 21, 2011
    Date of Patent: March 5, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yoshinao Suzuki, Yuui Shimizu
  • Patent number: 8374032
    Abstract: A non-volatile semiconductor memory device including: a NAND string having multiple memory cells connected in series and first and second select gate transistors disposed on the both ends; word lines coupled to the memory cells; and first and second select gate lines coupled to the first and second select gate transistors, wherein a data read mode is defined by the following bias condition: a selected word line is applied with a read voltage; one adjacent to the selected word line within first unselected word lines disposed on the first select gate line side is applied with a first read pass voltage while the others are applied with a second read pass voltage lower than the first read pass voltage; and second unselected word lines disposed on the second select gate line side are applied with a third read pass voltage higher than the first read voltage.
    Type: Grant
    Filed: June 15, 2011
    Date of Patent: February 12, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yuko Namiki, Takuya Futatsuyama, Yuui Shimizu
  • Publication number: 20130027108
    Abstract: According to one embodiment, a level shift circuit includes a plurality of level shift units which are connected to each other and in which the delay time of the rising edge of an output voltage is different from the delay time of the falling edge of the output voltage. The delay time of the rising edge of the output voltage from the previous level shift unit is compensated by the delay time of the falling edge of the output voltage from the next level shift unit, and the delay time of the falling edge of the output voltage from the previous level shift unit is compensated by the delay time of the rising edge of the output voltage from the next level shift unit.
    Type: Application
    Filed: June 15, 2012
    Publication date: January 31, 2013
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Yuui SHIMIZU, Masaru KOYANAGI
  • Patent number: 8315108
    Abstract: According to one embodiment, a differential circuit receives, as differential inputs, a readout signal read out from a semiconductor storage element and a reference voltage. An equalizing circuit controls, taking into account a state of a past input signal output from the differential circuit, the potential of the present differential signal output from the differential circuit. A sense amplifier detects a state of the differential signal output from the equalizing circuit. A state holding circuit holds a past state of the differential signal detected by the sense amplifier and supplies the state to the equalizing circuit.
    Type: Grant
    Filed: September 17, 2010
    Date of Patent: November 20, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Yuui Shimizu
  • Patent number: 8179730
    Abstract: A semiconductor device, a semiconductor memory tester, and a multi-chip package are provided. The semiconductor device includes a plurality of nonvolatile semiconductor memories; a boosting circuit which generates a boosted voltage for operating the plurality of nonvolatile semiconductor memories; and a boosting circuit controller which controls the operation of the boosting circuit to generate the boosted voltage on the basis of an operation sequence of the plurality of nonvolatile semiconductor memories.
    Type: Grant
    Filed: December 8, 2010
    Date of Patent: May 15, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yuui Shimizu, Shigeo Ohshima, Mie Matsuo
  • Publication number: 20120069530
    Abstract: According to one embodiment, a semiconductor device includes a stacked chip includes semiconductor chips which are stacked, the semiconductor chips comprises semiconductor substrates and through electrodes formed in the semiconductor substrates, respectively, the through electrodes being electrically connected, and deactivating circuits provided in the semiconductor chips, respectively, and configured to deactivate a failed semiconductor chip.
    Type: Application
    Filed: September 16, 2011
    Publication date: March 22, 2012
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Satoshi Inoue, Kazushige Kanda, Yuui Shimizu
  • Publication number: 20120025865
    Abstract: According to one embodiment, an input circuit includes an input buffer, a control unit, a holding unit, a feedback unit. The input buffer receives a signal input from an outside. The input buffer includes a plurality of CMOS inverters connected in parallel. The plurality of CMOS inverters includes a plurality of PMOS transistors and a plurality of NMOS transistors. The control unit selects one or more PMOS transistors from the plurality of PMOS transistors so as to enter an operable state. The control unit selects one or more NMOS transistors from the plurality of NMOS transistors so as to enter an operable state. The holding unit holds a level of a signal transferred from the input buffer in synchronization with a clock signal. The holding unit outputs the held signal level. The feedback unit feeds the level of the signal output from the holding unit back to the control unit.
    Type: Application
    Filed: July 27, 2011
    Publication date: February 2, 2012
    Applicant: Kabushiki Kaisha Toshiba
    Inventor: Yuui SHIMIZU
  • Publication number: 20110305086
    Abstract: A memory includes stacking chips. The chip includes a pad commonly connected to the chips and receiving an enable signal that enables access to each chip. The chip includes a chip address memory that can store a chip address. The chip includes a determining part comparing a select address to the chip address for determining whether they match each other. The chip includes a control-signal setting part setting the control signal inputted to the chip itself to be valid or invalid depending on a determination made by the determining part. The chip includes a chip-address setting part determining whether the chip address is stored in the chip address memory depending on number of fail bits. The device includes a memory controller allocating respectively different ones of the chip addresses to the chips based on the number of fail bits.
    Type: Application
    Filed: June 14, 2011
    Publication date: December 15, 2011
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Tomofumi FUJIMURA, Yuui SHIMIZU
  • Publication number: 20110267864
    Abstract: According to one embodiment, a nonvolatile semiconductor memory device includes a first memory chip, a second memory chip, and a control chip. The first chip includes a first inductor configured to transmit/receive a signal, and a memory cell. The second chip is disposed on the first chip and includes a second inductor configured to transmit/receive a signal, and a memory cell. The control chip includes a control circuit configured to control the first and second chips, and a third inductor configured to transmit/receive a signal to/from the first and second inductors. The outer peripheries of the first and second inductors are included in a closed space produced by extending the outer periphery of the third inductor in a direction perpendicular to a plane that includes the third inductor. The inductance of the third inductor is greater than at least one of the inductances of the first and second inductors.
    Type: Application
    Filed: March 21, 2011
    Publication date: November 3, 2011
    Inventors: Yoshinao SUZUKI, Yuui SHIMIZU
  • Publication number: 20110242892
    Abstract: A non-volatile semiconductor memory device including: a NAND string having multiple memory cells connected in series and first and second select gate transistors disposed on the both ends; word lines coupled to the memory cells; and first and second select gate lines coupled to the first and second select gate transistors, wherein a data read mode is defined by the following bias condition: a selected word line is applied with a read voltage; one adjacent to the selected word line within first unselected word lines disposed on the first select gate line side is applied with a first read pass voltage while the others are applied with a second read pass voltage lower than the first read pass voltage; and second unselected word lines disposed on the second select gate line side are applied with a third read pass voltage higher than the first read voltage.
    Type: Application
    Filed: June 15, 2011
    Publication date: October 6, 2011
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Yuko NAMIKI, Takuya Futatsuyama, Yuui Shimizu