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).

  • Publication number: 20100172200
    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: Application
    Filed: November 4, 2009
    Publication date: July 8, 2010
    Applicant: FUJITSU 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
  • Publication number: 20100146201
    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: Application
    Filed: November 4, 2009
    Publication date: June 10, 2010
    Applicant: FUJITSU 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: 7688661
    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 22, 2008
    Date of Patent: March 30, 2010
    Assignee: Fujitsu Microelectronics Limited
    Inventors: Shinya Fujioka, Tomohiro Kawakubo, Koichi Nishimura, Kotoku Sato
  • Patent number: 7633825
    Abstract: A semiconductor memory device includes a DRAM memory core circuit including a word line, a power supply circuit configured to operate in a selected one of a first state and a second state to generate a predetermined power supply voltage for provision to the DRAM memory core circuit, the power supply circuit consuming a larger electric current in the first state than in the second state, and a control circuit configured to control the power supply circuit such that the power supply circuit is shifted from the first state to the second state, and is then brought back to the first state during a period from activation of the word line to deactivation of the word line.
    Type: Grant
    Filed: May 15, 2007
    Date of Patent: December 15, 2009
    Assignee: Fujitsu Microelectronics Limited
    Inventors: Yoshiaki Okuyama, Atsushi Takeuchi, Tomohiro Kawakubo
  • Publication number: 20090190418
    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: Application
    Filed: September 11, 2008
    Publication date: July 30, 2009
    Applicant: FUJITSU MICROELECTRONICS LIMITED
    Inventors: Toshikazu NAKAMURA, Tomohiro KAWAKUBO
  • Patent number: 7552369
    Abstract: A semiconductor device includes a memory cell array, in which bit lines intersect word lines to form a memory cell. Representative pads are selected from among pads. Data input to the representative pads is decompressed to data corresponding to all of the pads, and is written in corresponding memory cells. The data is read and divided into number of groups corresponding to number of the representative pads. It is determined whether the data in each group coincide with the data input to the representative pads. Output to the representative pads is controlled based on a result of the determination.
    Type: Grant
    Filed: March 30, 2005
    Date of Patent: June 23, 2009
    Assignee: Fujitsu Microelectronics Limited
    Inventor: Tomohiro Kawakubo
  • Publication number: 20090089493
    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: Application
    Filed: September 22, 2008
    Publication date: April 2, 2009
    Applicant: FUJITSU MICROELECTRONICS LIMITED
    Inventors: Hitoshi IKEDA, Takahiko Sato, Tomohiro Kawakubo
  • Patent number: 7495986
    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 27, 2005
    Date of Patent: February 24, 2009
    Assignee: Fujitsu Microelectronic Limited
    Inventors: Shinya Fujioka, Tomohiro Kawakubo, Koichi Nishimura, Kotoku Sato
  • Patent number: 7483323
    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 27, 2009
    Assignee: Fujitsu Microelectronics Limited
    Inventors: Shinya Fujioka, Tomohiro Kawakubo, Koichi Nishimura, Kotoku Sato
  • Publication number: 20090016142
    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: September 22, 2008
    Publication date: January 15, 2009
    Inventors: Shinya FUJIOKA, Tomohiro KAWAKUBO, Koichi NISHIMURA, Kotoku SATO
  • Publication number: 20090010080
    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: August 29, 2008
    Publication date: January 8, 2009
    Inventors: Shinya Fujioka, Tomohiro Kawakubo, Koichi Nishimura, Kotoku Sato
  • Patent number: 7471587
    Abstract: A core control circuit outputs operation control signals to a memory core in order to perform refresh operations in response to an internal refresh request from a refresh request generating circuit and an external refresh request. The core control circuit sets the number of memory cells each subjected to the refresh operation in response to the external refresh request larger than the number of memory cells each subjected to the refresh operations in response to the internal refresh request. By relatively increasing the number of memory cells each subjected to the refresh operation in response to one external refresh request, the number of external refresh requests required to refresh all memory cells can be reduced. Accordingly, the frequency with which the external refresh request is supplied to the semiconductor memory can be lowered, which can improve access efficiency.
    Type: Grant
    Filed: May 2, 2007
    Date of Patent: December 30, 2008
    Assignee: Fujitsu Limited
    Inventor: Tomohiro Kawakubo
  • Publication number: 20080151670
    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: Application
    Filed: February 23, 2007
    Publication date: June 26, 2008
    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
  • Publication number: 20070268769
    Abstract: A semiconductor memory device includes a DRAM memory core circuit including a word line, a power supply circuit configured to operate in a selected one of a first state and a second state to generate a predetermined power supply voltage for provision to the DRAM memory core circuit, the power supply circuit consuming a larger electric current in the first state than in the second state, and a control circuit configured to control the power supply circuit such that the power supply circuit is shifted from the first state to the second state, and is then brought back to the first state during a period from activation of the word line to deactivation of the word line.
    Type: Application
    Filed: May 15, 2007
    Publication date: November 22, 2007
    Inventors: Yoshiaki Okuyama, Atsushi Takeuchi, Tomohiro Kawakubo
  • Publication number: 20070268768
    Abstract: A core control circuit outputs operation control signals to a memory core in order to perform refresh operations in response to an internal refresh request from a refresh request generating circuit and an external refresh request. The core control circuit sets the number of memory cells each subjected to the refresh operation in response to the external refresh request larger than the number of memory cells each subjected to the refresh operations in response to the internal refresh request. By relatively increasing the number of memory cells each subjected to the refresh operation in response to one external refresh request, the number of external refresh requests required to refresh all memory cells can be reduced. Accordingly, the frequency with which the external refresh request is supplied to the semiconductor memory can be lowered, which can improve access efficiency.
    Type: Application
    Filed: May 2, 2007
    Publication date: November 22, 2007
    Inventor: Tomohiro Kawakubo
  • Publication number: 20070014178
    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: September 6, 2006
    Publication date: January 18, 2007
    Inventors: Shinya Fujioka, Tomohiro Kawakubo, Koichi Nishimura, Kotoku Sato
  • Publication number: 20070002664
    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: September 6, 2006
    Publication date: January 4, 2007
    Inventors: Shinya Fujioka, Tomohiro Kawakubo, Koichi Nishimura, Kotoku Sato
  • Publication number: 20060092681
    Abstract: A semiconductor device includes a memory cell array, in which bit lines intersect word lines to form a memory cell. Representative pads are selected from among pads. Data input to the representative pads is decompressed to data corresponding to all of the pads, and is written in corresponding memory cells. The data is read and divided into number of groups corresponding to number of the representative pads. It is determined whether the data in each group coincide with the data input to the representative pads. Output to the representative pads is controlled based on a result of the determination.
    Type: Application
    Filed: March 30, 2005
    Publication date: May 4, 2006
    Inventor: Tomohiro Kawakubo
  • Publication number: 20050262369
    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 27, 2005
    Publication date: November 24, 2005
    Inventors: Shinya Fujioka, Tomohiro Kawakubo, Koichi Nishimura, Kotoku Sato
  • Patent number: 6845055
    Abstract: A semiconductor memory that can make the transition from a power-down state in a synchronous mode to an asynchronous mode without setting by a control register and that needs no extra circuits. A state selection section chooses, by selecting an existing internal signal the level of which changes in the power-down state or an existing internal signal the level of which does not change in the power-down state in accordance with a state selection signal inputted in advance and passing a signal selected to a synchronous/asynchronous mode setting section, whether the semiconductor memory should make the transition from the power-down state to a standby state in the synchronous mode or a standby state in the asynchronous mode. In accordance with the selection by the state selection section, the synchronous/asynchronous mode setting section generates a signal for causing the semiconductor memory to make the transition between the synchronous mode and the asynchronous mode.
    Type: Grant
    Filed: June 15, 2004
    Date of Patent: January 18, 2005
    Assignee: Fujitsu Limited
    Inventors: Toru Koga, Tomohiro Kawakubo, Tatsuya Kanda