Patents by Inventor Tomohiro Kawakubo

Tomohiro Kawakubo 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: 8730744
    Abstract: A semiconductor memory has a memory cell array having a plurality of real word lines, a plurality of redundant word lines, a plurality of bit lines crossing with the real and redundant word lines, a plurality of memory cells provided at crossing section of the real and redundant word lines and the bit lines, and a row selection circuit for selecting the real word line or the redundant word line in accordance with a row address being supplied. The row selection circuit selects the real word line or the redundant word line at an ordinary operation, and multi-selects the redundant word lines at a first test mode.
    Type: Grant
    Filed: May 17, 2012
    Date of Patent: May 20, 2014
    Assignee: Fujitsu Semiconductor Limited
    Inventor: Tomohiro Kawakubo
  • Patent number: 8619487
    Abstract: A semiconductor device includes a memory core with a plurality of memory cells, an internal voltage generator and a low power entry circuit. The low power entry circuit receives a plurality of control signals which are provided to a command decoder, and generates a low power signal indicating a low power consumption mode where a refresh operation is prohibited. The internal voltage generator includes a detector and at least one of booster circuits. The internal voltage generator, coupled to the memory core via an internal power supply line, generates a boosted internal voltage based on an external voltage and supplies the boosted internal voltage to the memory core via the internal power supply line. The internal voltage generator stops supplying the boosted internal voltage to the internal power supply line in response to the low power signal while the external voltage is supplied to the semiconductor device.
    Type: Grant
    Filed: January 23, 2012
    Date of Patent: December 31, 2013
    Assignee: Fujitsu Semiconductor Limited
    Inventors: Shinya Fujioka, Tomohiro Kawakubo, Koichi Nishimura, Kotoku Sato
  • Publication number: 20130332761
    Abstract: A semiconductor device includes a memory core with a plurality of memory cells, an internal voltage generator and a low power entry circuit. The low power entry circuit receives a plurality of control signals which are provided to a command decoder, and generates a low power signal indicating a low power consumption mode where a refresh operation is prohibited. The internal voltage generator includes a detector and at least one of booster circuits. The internal voltage generator, coupled to the memory core via an internal power supply line, generates a boosted internal voltage based on an external voltage and supplies the boosted internal voltage to the memory core via the internal power supply line. The internal voltage generator stops supplying the boosted internal voltage to the internal power supply line in response to the low power signal while the external voltage is supplied to the semiconductor device.
    Type: Application
    Filed: August 6, 2013
    Publication date: December 12, 2013
    Applicant: FUJITSU SEMICONDUCTOR LIMITED
    Inventors: Shinya FUJIOKA, Tomohiro Kawakubo, Koichi Nishimura, Kotoku Sato
  • Publication number: 20130326247
    Abstract: A semiconductor device includes a memory core with a plurality of memory cells, an internal voltage generator and a low power entry circuit. The low power entry circuit receives a plurality of control signals which are provided to a command decoder, and generates a low power signal indicating a low power consumption mode where a refresh operation is prohibited. The internal voltage generator includes a detector and at least one of booster circuits. The internal voltage generator, coupled to the memory core via an internal power supply line, generates a boosted internal voltage based on an external voltage and supplies the boosted internal voltage to the memory core via the internal power supply line. The internal voltage generator stops supplying the boosted internal voltage to the internal power supply line in response to the low power signal while the external voltage is supplied to the semiconductor device.
    Type: Application
    Filed: August 6, 2013
    Publication date: December 5, 2013
    Applicant: FUJITSU SEMICONDUCTOR LIMITED
    Inventors: Shinya FUJIOKA, Tomohiro Kawakubo, Koichi Nishimura, Kotoku Sato
  • Publication number: 20130326246
    Abstract: A semiconductor device includes a memory core with a plurality of memory cells, an internal voltage generator and a low power entry circuit. The low power entry circuit receives a plurality of control signals which are provided to a command decoder, and generates a low power signal indicating a low power consumption mode where a refresh operation is prohibited. The internal voltage generator includes a detector and at least one of booster circuits. The internal voltage generator, coupled to the memory core via an internal power supply line, generates a boosted internal voltage based on an external voltage and supplies the boosted internal voltage to the memory core via the internal power supply line. The internal voltage generator stops supplying the boosted internal voltage to the internal power supply line in response to the low power signal while the external voltage is supplied to the semiconductor device.
    Type: Application
    Filed: August 6, 2013
    Publication date: December 5, 2013
    Applicant: FUJITSU SEMICONDUCTOR LIMITED
    Inventors: Shinya FUJIOKA, Tomohiro Kawakubo, Koichi Nishimura, Kotoku Sato
  • Publication number: 20130326248
    Abstract: A semiconductor device includes a memory core with a plurality of memory cells, an internal voltage generator and a low power entry circuit. The low power entry circuit receives a plurality of control signals which are provided to a command decoder, and generates a low power signal indicating a low power consumption mode where a refresh operation is prohibited. The internal voltage generator includes a detector and at least one of booster circuits. The internal voltage generator, coupled to the memory core via an internal power supply line, generates a boosted internal voltage based on an external voltage and supplies the boosted internal voltage to the memory core via the internal power supply line. The internal voltage generator stops supplying the boosted internal voltage to the internal power supply line in response to the low power signal while the external voltage is supplied to the semiconductor device.
    Type: Application
    Filed: August 6, 2013
    Publication date: December 5, 2013
    Applicant: FUJITSU SEMICONDUCTOR LIMITED
    Inventors: Shinya Fujioka, Tomohiro Kawakubo, Koichi Nishimura, Kotoku Sato
  • Publication number: 20130322198
    Abstract: A semiconductor device includes a memory core with a plurality of memory cells, an internal voltage generator and a low power entry circuit. The low power entry circuit receives a plurality of control signals which are provided to a command decoder, and generates a low power signal indicating a low power consumption mode where a refresh operation is prohibited. The internal voltage generator includes a detector and at least one of booster circuits. The internal voltage generator, coupled to the memory core via an internal power supply line, generates a boosted internal voltage based on an external voltage and supplies the boosted internal voltage to the memory core via the internal power supply line. The internal voltage generator stops supplying the boosted internal voltage to the internal power supply line in response to the low power signal while the external voltage is supplied to the semiconductor device.
    Type: Application
    Filed: August 6, 2013
    Publication date: December 5, 2013
    Applicant: Fujitsu Semiconductor Limited
    Inventors: Shinya FUJIOKA, Tomohiro KAWAKUBO, Koichi NISHIMURA, Kotoku SATO
  • Publication number: 20130315020
    Abstract: A semiconductor device includes a memory core with a plurality of memory cells, an internal voltage generator and a low power entry circuit. The low power entry circuit receives a plurality of control signals which are provided to a command decoder, and generates a low power signal indicating a low power consumption mode where a refresh operation is prohibited. The internal voltage generator includes a detector and at least one of booster circuits. The internal voltage generator, coupled to the memory core via an internal power supply line, generates a boosted internal voltage based on an external voltage and supplies the boosted internal voltage to the memory core via the internal power supply line. The internal voltage generator stops supplying the boosted internal voltage to the internal power supply line in response to the low power signal while the external voltage is supplied to the semiconductor device.
    Type: Application
    Filed: August 6, 2013
    Publication date: November 28, 2013
    Applicant: FUJITSU SEMICONDUCTOR LIMITED
    Inventors: Shinya FUJIOKA, Tomohiro Kawakubo, Koichi Nishimura, Kotoku Sato
  • Publication number: 20130318293
    Abstract: A semiconductor device includes a memory core with a plurality of memory cells, an internal voltage generator and a low power entry circuit. The low power entry circuit receives a plurality of control signals which are provided to a command decoder, and generates a low power signal indicating a low power consumption mode where a refresh operation is prohibited. The internal voltage generator includes a detector and at least one of booster circuits. The internal voltage generator, coupled to the memory core via an internal power supply line, generates a boosted internal voltage based on an external voltage and supplies the boosted internal voltage to the memory core via the internal power supply line. The internal voltage generator stops supplying the boosted internal voltage to the internal power supply line in response to the low power signal while the external voltage is supplied to the semiconductor device.
    Type: Application
    Filed: August 6, 2013
    Publication date: November 28, 2013
    Applicant: FUJITSU SEMICONDUCTOR LIMITED
    Inventors: Shinya FUJIOKA, Tomohiro KAWAKUBO, Koichi NISHIMURA, Kotoku SATO
  • Publication number: 20130315012
    Abstract: A semiconductor device includes a memory core with a plurality of memory cells, an internal voltage generator and a low power entry circuit. The low power entry circuit receives a plurality of control signals which are provided to a command decoder, and generates a low power signal indicating a low power consumption mode where a refresh operation is prohibited. The internal voltage generator includes a detector and at least one of booster circuits. The internal voltage generator, coupled to the memory core via an internal power supply line, generates a boosted internal voltage based on an external voltage and supplies the boosted internal voltage to the memory core via the internal power supply line. The internal voltage generator stops supplying the boosted internal voltage to the internal power supply line in response to the low power signal while the external voltage is supplied to the semiconductor device.
    Type: Application
    Filed: August 6, 2013
    Publication date: November 28, 2013
    Applicant: FUJITSU SEMICONDUCTOR LIMITED
    Inventors: Shinya FUJIOKA, Tomohiro KAWAKUBO, Koichi NISHIMURA, Kotoku SATO
  • Publication number: 20120327724
    Abstract: A semiconductor memory has a memory cell array having a plurality of real word lines, a plurality of redundant word lines, a plurality of bit lines crossing with the real and redundant word lines, a plurality of memory cells provided at crossing section of the real and redundant word lines and the bit lines, and a row selection circuit for selecting the real word line or the redundant word line in accordance with a row address being supplied. The row selection circuit selects the real word line or the redundant word line at an ordinary operation, and multi-selects the redundant word lines at a first test mode.
    Type: Application
    Filed: May 17, 2012
    Publication date: December 27, 2012
    Applicant: FUJITSU SEMICONDUCTOR LIMITED
    Inventor: Tomohiro KAWAKUBO
  • Publication number: 20120120739
    Abstract: An internal voltage generator when activated, generates an internal voltage to be supplied to an internal circuit. Operating the internal voltage generator consumes a predetermined amount of the power. In response to a control signal from the exterior, an entry circuit inactivates the internal voltage generator. When the internal voltage generator is inactivated, the internal voltage is not generated, thereby reducing the power consumption. By the control signal from the exterior, therefore, a chip can easily enter a low power consumption mode. The internal voltage generator is exemplified by a booster for generating the boost voltage of a word line connected with memory cells, a substrate voltage generator for generating a substrate voltage, or a precharging voltage generator for generating the precharging voltage of bit lines to be connected with the memory cells.
    Type: Application
    Filed: January 23, 2012
    Publication date: May 17, 2012
    Applicant: FUJITSU SEMICONDUCTOR LIMITED
    Inventors: Shinya FUJIOKA, Tomohiro Kawakubo, Koichi Nishimura, Kotoku Sato
  • Patent number: 8171210
    Abstract: Operation control circuits start a first operation of any of memory cores in response to a first operation command, start a second operation of any of the memory cores in response to a second operation command, and terminate the first operation and continue the second operation in response to a termination command to terminate operations of the plurality of memory cores. For example, the semiconductor memory is mounted on a system together with a controller accessing the semiconductor memory. The termination of the operation in response to the termination command is judged in accordance with an operation state of the memory core. Accordingly, it is possible to terminate the operation of the memory core requiring the termination of operation without specifying the memory core from outside.
    Type: Grant
    Filed: September 22, 2008
    Date of Patent: May 1, 2012
    Assignee: Fujitsu Semiconductor Limited
    Inventors: Hitoshi Ikeda, Takahiko Sato, Tomohiro Kawakubo
  • Patent number: 8130586
    Abstract: An internal voltage generator when activated, generates an internal voltage to be supplied to an internal circuit. Operating the internal voltage generator consumes a predetermined amount of the power. In response to a control signal from the exterior, an entry circuit inactivates the internal voltage generator. When the internal voltage generator is inactivated, the internal voltage is not generated, thereby reducing the power consumption. By the control signal from the exterior, therefore, a chip can easily enter a low power consumption mode. The internal voltage generator is exemplified by a booster for generating the boost voltage of a word line connected with memory cells, a substrate voltage generator for generating a substrate voltage, or a precharging voltage generator for generating the precharging voltage of bit lines to be connected with the memory cells.
    Type: Grant
    Filed: July 30, 2010
    Date of Patent: March 6, 2012
    Assignee: Fujitsu Semiconductor Limited
    Inventors: Shinya Fujioka, Tomohiro Kawakubo, Koichi Nishimura, Kotoku Sato
  • Patent number: 8077537
    Abstract: Provided is a memory device in which the decrease of the effective bandwidth caused by the refresh operation of the memory device has been solved, a memory controller of the memory device, and a memory system thereof.
    Type: Grant
    Filed: November 4, 2009
    Date of Patent: December 13, 2011
    Assignee: Fujitsu Semiconductor Limited
    Inventors: Tomohiro Kawakubo, Syusaku Yamaguchi, Hitoshi Ikeda, Toshiya Uchida, Hiroyuki Kobayashi, Tatsuya Kanda, Yoshinobu Yamamoto, Satoru Shirakawa, Tetsuo Miyamoto, Tatsushi Otsuka, Hidenaga Takahashi, Masanori Kurita, Shinnosuke Kamata, Ayako Sato
  • Patent number: 8004921
    Abstract: Provided is a memory device in which the decrease of the effective bandwidth caused by the refresh operation of the memory device has been solved, a memory controller of the memory device, and a memory system thereof.
    Type: Grant
    Filed: November 4, 2009
    Date of Patent: August 23, 2011
    Assignee: Fujitsu Semiconductor Limited
    Inventors: Tomohiro Kawakubo, Syusaku Yamaguchi, Hitoshi Ikeda, Toshiya Uchida, Hiroyuki Kobayashi, Tatsuya Kanda, Yoshinobu Yamamoto, Satoru Shirakawa, Tetsuo Miyamoto, Tatsushi Otsuka, Hidenaga Takahashi, Masanori Kurita, Shinnosuke Kamata, Ayako Sato
  • Patent number: 7903487
    Abstract: An internal voltage generator when activated, generates an internal voltage to be supplied to an internal circuit. Operating the internal voltage generator consumes a predetermined amount of the power. In response to a control signal from the exterior, an entry circuit inactivates the internal voltage generator. When the internal voltage generator is inactivated, the internal voltage is not generated, thereby reducing the power consumption. By the control signal from the exterior, therefore, a chip can easily enter a low power consumption mode. The internal voltage generator is exemplified by a booster for generating the boost voltage of a word line connected with memory cells, a substrate voltage generator for generating a substrate voltage, or a precharging voltage generator for generating the precharging voltage of bit lines to be connected with the memory cells.
    Type: Grant
    Filed: August 29, 2008
    Date of Patent: March 8, 2011
    Assignee: Fujitsu Semiconductor Limited
    Inventors: Shinya Fujioka, Tomohiro Kawakubo, Koichi Nishimura, Kotoku Sato
  • Patent number: 7869296
    Abstract: An internal voltage generator when activated, generates an internal voltage to be supplied to an internal circuit. Operating the internal voltage generator consumes a predetermined amount of the power. In response to a control signal from the exterior, an entry circuit inactivates the internal voltage generator. When the internal voltage generator is inactivated, the internal voltage is not generated, thereby reducing the power consumption. By the control signal from the exterior, therefore, a chip can easily enter a low power consumption mode. The internal voltage generator is exemplified by a booster for generating the boost voltage of a word line connected with memory cells, a substrate voltage generator for generating a substrate voltage, or a precharging voltage generator for generating the precharging voltage of bit lines to be connected with the memory cells.
    Type: Grant
    Filed: September 6, 2006
    Date of Patent: January 11, 2011
    Assignee: Fujitsu Semiconductor Limited
    Inventors: Shinya Fujioka, Tomohiro Kawakubo, Koichi Nishimura, Kotoku Sato
  • Publication number: 20100302879
    Abstract: An internal voltage generator when activated, generates an internal voltage to be supplied to an internal circuit. Operating the internal voltage generator consumes a predetermined amount of the power. In response to a control signal from the exterior, an entry circuit inactivates the internal voltage generator. When the internal voltage generator is inactivated, the internal voltage is not generated, thereby reducing the power consumption. By the control signal from the exterior, therefore, a chip can easily enter a low power consumption mode. The internal voltage generator is exemplified by a booster for generating the boost voltage of a word line connected with memory cells, a substrate voltage generator for generating a substrate voltage, or a precharging voltage generator for generating the precharging voltage of bit lines to be connected with the memory cells.
    Type: Application
    Filed: July 30, 2010
    Publication date: December 2, 2010
    Applicant: FUJITSU SEMICONDUCTOR LIMITED
    Inventors: Shinya FUJIOKA, Tomohiro Kawakubo, Koichi Nishimura, Kotoku Sato
  • Patent number: 7755957
    Abstract: A semiconductor memory comprising an address transition detection circuit for detecting a transition of an address and outputs an address detection signal; an address input circuit for inputting an input address based upon the address detection signal; a command judgment circuit for decoding a command signal input and outputting a command judgment signal; a redundancy circuit for making a redundancy judgment based upon a redundancy judgment signal indicating timing of a redundancy judgment, wherein the redundancy circuit includes a redundancy judgment speed-up circuit for controlling an output of the redundancy judgment signal based upon a predetermined command signal.
    Type: Grant
    Filed: September 11, 2008
    Date of Patent: July 13, 2010
    Assignee: Fujitsu Semiconductor Limited
    Inventors: Toshikazu Nakamura, Tomohiro Kawakubo