Patents by Inventor Ayako Kitamoto

Ayako Kitamoto 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: 20100321983
    Abstract: A semiconductor device includes a word line drive circuit for resetting the word line by driving the word line connected to a memory cell and is constituted so as to switch a reset level of the word line drive circuit, which is set at the time of the reset operation of the word line, between a first potential such as a ground potential and a second potential such as a negative potential. Further, a semiconductor device including a memory cell array formed by arranging a plurality of memory cells and a word line reset level generating circuit for generating a negative potential makes it possible to vary the amount of a current supply of the word line reset level generating circuit when non-selected word lines are set to a negative potential by applying the output of the word line reset level generating circuit to the non-selected word lines, and varies the amount of the current supply of the negative potential in accordance with the operation of the memory cell array.
    Type: Application
    Filed: March 5, 2010
    Publication date: December 23, 2010
    Applicant: FUJITSU MICROELECTRONICS LIMITED
    Inventors: Masato Takita, Masato Matsumiya, Satoshi Eto, Toshikazu Nakamura, Masatomo Hasegawa, Ayako Kitamoto, Kuninori Kawabata, Hideki Kanou, Toru Koga, Yuki Ishii, Shinichi Yamada, Kaoru Mori
  • Publication number: 20100220540
    Abstract: A semiconductor device includes a word line drive circuit for resetting the word line by driving the word line connected to a memory cell and is constituted so as to switch a reset level of the word line drive circuit, which is set at the time of the reset operation of the word line, between a first potential such as a ground potential and a second potential such as a negative potential. Further, a semiconductor device including a memory cell array formed by arranging a plurality of memory cells and a word line reset level generating circuit for generating a negative potential makes it possible to vary the amount of a current supply of the word line reset level generating circuit when non-selected word lines are set to a negative potential by applying the output of the word line reset level generating circuit to the non-selected word lines, and varies the amount of the current supply of the negative potential in accordance with the operation of the memory cell array.
    Type: Application
    Filed: March 5, 2010
    Publication date: September 2, 2010
    Applicant: FUJISU MICROELECTRONICS LIMITED
    Inventors: Masato Takita, Masato Matsumiya, Satoshi Eto, Toshikazu Nakamura, Masatomo Hasegawa, Ayako Kitamoto, Kuninori Kawabata, Hideki Kanou, Toru Koga, Yuki Ishii, Shinichi Yamada, Kaoru Mori
  • Patent number: 7706209
    Abstract: A semiconductor device, including a word line driver for driving a word line connected to a memory cell in a memory cell array and for resetting the word line when the memory cell changes from an activated to a standby state. The reset level of the word line driver is set when resetting of the word line is performed, and may be switched between first and second potentials. A word line reset level generating circuit varies the amount of negative potential current supply in accordance with memory cell array operating conditions. The semiconductor device includes a plurality of power source circuits, each having an oscillation circuit and a capacitor, for driving the capacitor via an oscillation signal outputted by the oscillation circuit. At least some power source circuits share a common oscillation circuit, and different capacitors are driven via the common oscillation signal.
    Type: Grant
    Filed: December 22, 2005
    Date of Patent: April 27, 2010
    Assignee: Fujitsu Microelectronics Limited
    Inventors: Masato Takita, Masato Matsumiya, Satoshi Eto, Toshikazu Nakamura, Masatomo Hasegawa, Ayako Kitamoto, Kuninori Kawabata, Hideki Kanou, Toru Koga, Yuki Ishii, Shinichi Yamada, Kaoru Mori
  • Patent number: 7079443
    Abstract: A semiconductor device includes a word line drive circuit for resetting the word line by driving the word line connected to a memory cell and is constituted so as to switch a reset level of the word line drive circuit, which is set at the time of the reset operation of the word line, between a first potential such as a ground potential and a second potential such as a negative potential. Further, a semiconductor device including a memory cell array formed by arranging a plurality of memory cells and a word line reset level generating circuit for generating a negative potential makes it possible to vary the amount of a current supply of the word line reset level generating circuit when non-selected word lines are set to a negative potential by applying the output of the word line reset level generating circuit to the non-selected word lines, and varies the amount of the current supply of the negative potential in accordance with the operation of the memory cell array.
    Type: Grant
    Filed: August 1, 2003
    Date of Patent: July 18, 2006
    Assignee: Fujitsu Limited
    Inventors: Masato Takita, Masato Matsumiya, Satoshi Eto, Toshikazu Nakamura, Masatomo Hasegawa, Ayako Kitamoto, Kuninori Kawabata, Hideki Kanou, Toru Koga, Yuki Ishii, Shinichi Yamada, Kaoru Mori
  • Publication number: 20060098523
    Abstract: A semiconductor device includes a word line drive circuit for resetting the word line by driving the word line connected to a memory cell and is constituted so as to switch a reset level of the word line drive circuit, which is set at the time of the reset operation of the word line, between a first potential such as a ground potential and a second potential such as a negative potential. Further, a semiconductor device including a memory cell array formed by arranging a plurality of memory cells and a word line reset level generating circuit for generating a negative potential makes it possible to vary the amount of a current supply of the word line reset level generating circuit when non-selected word lines are set to a negative potential by applying the output of the word line reset level generating circuit to the non-selected word lines, and varies the amount of the current supply of the negative potential in accordance with the operation of the memory cell array.
    Type: Application
    Filed: December 22, 2005
    Publication date: May 11, 2006
    Inventors: Masato Takita, Masato Matsumiya, Satoshi Eto, Toshikazu Nakamura, Masatomo Hasegawa, Ayako Kitamoto, Kuninori Kawabata, Hideki Kanou, Toru Koga, Yuki Ishii, Shinichi Yamada, Kaoru Mori
  • Publication number: 20040022091
    Abstract: A semiconductor device includes a word line drive circuit for resetting the word line by driving the word line connected to a memory cell and is constituted so as to switch a reset level of the word line drive circuit, which is set at the time of the reset operation of the word line, between a first potential such as a ground potential and a second potential such as a negative potential. Further, a semiconductor device including a memory cell array formed by arranging a plurality of memory cells and a word line reset level generating circuit for generating a negative potential makes it possible to vary the amount of a current supply of the word line reset level generating circuit when non-selected word lines are set to a negative potential by applying the output of the word line reset level generating circuit to the non-selected word lines, and varies the amount of the current supply of the negative potential in accordance with the operation of the memory cell array.
    Type: Application
    Filed: August 1, 2003
    Publication date: February 5, 2004
    Applicant: FUJITSU LIMITED
    Inventors: Masato Takita, Masato Matsumiya, Satoshi Eto, Toshikazu Nakamura, Masatomo Hasegawa, Ayako Kitamoto, Kuninori Kawabata, Hideki Kanou, Toru Koga, Yuki Ishii, Shinichi Yamada, Kaoru Mori
  • Patent number: 6628564
    Abstract: A semiconductor device includes a word line drive circuit resetting the word line by driving the word line connected to a memory cell and switching a reset level of the word line drive circuit at the time of the reset operation of the word line. Further, a semiconductor device includes a memory cell array formed by arranging a plurality of memory cells and a reset level switch circuit for selecting a first potential or a second potential and supplying the first potential or the second potential to the word line drive circuit.
    Type: Grant
    Filed: June 25, 1999
    Date of Patent: September 30, 2003
    Assignee: Fujitsu Limited
    Inventors: Masato Takita, Masato Matsumiya, Satoshi Eto, Toshikazu Nakamura, Masatomo Hasegawa, Ayako Kitamoto, Kuninori Kawabata, Hideki Kanou, Toru Koga, Yuki Ishii, Shinichi Yamada, Kaoru Mori
  • Patent number: 6621327
    Abstract: Transistors are supplied with either a first power supply voltage or a second power supply voltage lower than the first power supply voltage. During an operation period of the transistors, substrate voltages of the transistors are set at a value between the first power supply voltage and the second power supply voltage. The substrate voltages are changed to lower threshold voltages of the transistors so that the transistors improve in drivability and operating speed. Therefore, neither a booster for generating higher voltages nor a pumping circuit for generating negative voltages is particularly required. This allows a reduction in layout size. Besides, in accordance with the operating state of the semiconductor integrated circuit, the transistor characteristics can be easily changed by changing the threshold voltages of the transistors.
    Type: Grant
    Filed: January 16, 2003
    Date of Patent: September 16, 2003
    Assignee: Fujitsu Limited
    Inventor: Ayako Kitamoto
  • Patent number: 6611472
    Abstract: The present invention is that, in a memory circuit comprising a cell array and peripheral circuit, the cell array power source is supplied to a circuit which operates during the power-down mode in addition to the cell array. The circuit which operates during the power-down mode is, for example, a self-refresh circuit. A dynamic memory requires refreshing operations in fixed intervals even during the power-down mode. Therefore, the self-refresh circuit is operating even during the power-down mode. Thus, by supplying the cell array power source to the self-refresh circuit, it is possible to consume a prescribed quantity of current from the cell array power source generation circuit to an extent of being able to maintain the level thereof even during the power-down mode. The cell array power source may be maintained within an appropriate voltage range thereby.
    Type: Grant
    Filed: February 6, 2001
    Date of Patent: August 26, 2003
    Assignee: Fujitsu Limited
    Inventors: Ayako Kitamoto, Kaoru Mori
  • Patent number: 6605963
    Abstract: A semiconductor integrated circuit, comprising a circuit unit having a predetermined function such as a level shifter circuit or a driver transistor circuit by a combination of a plurality of transistors, is disclosed. Among a plurality of the transistors of the circuit unit, the source potential of at least one transistor adapted to turn off during the standby period of the circuit unit is changed. Preferably, the semiconductor integrated circuit is configured to reduce the sub-threshold current flowing between the source and the drain of at least one transistor adapted to turn off during the standby period of the circuit unit by changing the source potential at a timing based on the standby period of the circuit unit in such a manner that a predetermined bias voltage is applied between the gate and the source of the transistor. A method of switching the source potential of at least one transistor in the semiconductor integrated circuit having the configuration described above is also disclosed.
    Type: Grant
    Filed: October 5, 1999
    Date of Patent: August 12, 2003
    Assignee: Fujitsu Limited
    Inventors: Ayako Kitamoto, Masato Matsumiya, Satoshi Eto, Masato Takita, Toshikazu Nakamura, Hideki Kanou, Kuninori Kawabata, Masatomo Hasegawa, Toru Koga, Yuki Ishii
  • Publication number: 20030102902
    Abstract: Transistors are supplied with either a first power supply voltage or a second power supply voltage lower than the first power supply voltage. During an operation period of the transistors, substrate voltages of the transistors are set at a value between the first power supply voltage and the second power supply voltage. The substrate voltages are changed to lower threshold voltages of the transistors so that the transistors improve in drivability and operating speed. Therefore, neither a booster for generating higher voltages nor a pumping circuit for generating negative voltages is particularly required. This allows a reduction in layout size. Besides, in accordance with the operating state of the semiconductor integrated circuit, the transistor characteristics can be easily changed by changing the threshold voltages of the transistors.
    Type: Application
    Filed: January 16, 2003
    Publication date: June 5, 2003
    Applicant: Fujitsu Limited
    Inventor: Ayako Kitamoto
  • Patent number: 6529434
    Abstract: A semiconductor memory device includes bit lines which transfer data of memory cells, a sense amplifier which is connected to the bit lines, and amplifies data on the bit lines that appears in response to an external access, and a latch circuit which is connected to the bit lines, and amplifies and latches data on the bit lines that appears as data to be refreshed.
    Type: Grant
    Filed: July 25, 2001
    Date of Patent: March 4, 2003
    Assignee: Fujitsu Limited
    Inventors: Ayako Kitamoto, Masato Matsumiya
  • Patent number: 6529440
    Abstract: A semiconductor memory device includes a DQ-quantity-selection signal generation circuit which generates a DQ-quantity-selection signal indicative of a number of input/output data bits, bit lines which transfer read data and write data for memory cells, and a plurality of sense amplifiers which are connected to the bit lines, and are activated as many as indicated by the DQ-quantity-selection signal.
    Type: Grant
    Filed: June 20, 2001
    Date of Patent: March 4, 2003
    Assignee: Fujitsu Limited
    Inventors: Ayako Kitamoto, Kaoru Mori
  • Patent number: 6515927
    Abstract: During a read operation, data read from memory cells onto bit lines are amplified simultaneously by sense amplifiers and outputted to the exterior of a memory. In this operation, a data control circuit outputs to the exterior all the data read from the memory cells onto the bit lines and amplified simultaneously by the sense amplifiers. During a write operation, data supplied from the exterior to the bit lines are amplified by the sense amplifiers and written into the memory cells. In this operation, the data control circuit writes into the memory cells all the data inputted from the exterior and amplified simultaneously by the sense amplifiers. Since all the data amplified simultaneously by the sense amplifiers are inputted/outputted from/to the exterior, the data transfer rate of the input/output data can be improved and the power consumption per unit amount of transferred data can be reduced.
    Type: Grant
    Filed: February 7, 2002
    Date of Patent: February 4, 2003
    Assignee: Fujitsu Limited
    Inventors: Ayako Kitamoto, Masato Matsumiya
  • Patent number: 6512717
    Abstract: A semiconductor memory device includes a core area formed of memory blocks each having a relaxed sense amplifier arrangement, a data bus including data bus lines corresponding to the memory blocks, a plurality of input/output terminals provided in number corresponding to the data bus lines forming the data bus, and a data path switch circuit provided between the data bus the input/output terminals for providing interconnection paths between the input/output terminals and the data bus lines, wherein the data path switch circuit switches a part of the interconnection paths in response to a switch control signal such that the input/output terminals are connected respectively to predetermined memory cells located at respective, predetermined physical locations in any of the memory blocks.
    Type: Grant
    Filed: July 29, 1996
    Date of Patent: January 28, 2003
    Assignee: Fujitsu Limited
    Inventors: Satoshi Eto, Masato Matsumiya, Shusaku Yamaguchi, Toshikazu Nakamura, Hideki Kano, Ayako Kitamoto, Mitsuhiro Higashiho
  • Publication number: 20030007403
    Abstract: During a read operation, data read from memory cells onto bit lines are amplified simultaneously by sense amplifiers and outputted to the exterior of a memory. In this operation, a data control circuit outputs to the exterior all the data read from the memory cells onto the bit lines and amplified simultaneously by the sense amplifiers. During a write operation, data supplied from the exterior to the bit lines are amplified by the sense amplifiers and written into the memory cells. In this operation, the data control circuit writes into the memory cells all the data inputted from the exterior and amplified simultaneously by the sense amplifiers. Since all the data amplified simultaneously by the sense amplifiers are inputted/outputted from/to the exterior, the data transfer rate of the input/output data can be improved and the power consumption per unit amount of transferred data can be reduced.
    Type: Application
    Filed: February 7, 2002
    Publication date: January 9, 2003
    Applicant: FUJITSU LIMITED
    Inventors: Ayako Kitamoto, Masato Matsumiya
  • Publication number: 20020145447
    Abstract: A semiconductor integrated circuit, comprising a circuit unit having a predetermined function such as a level shifter circuit or a driver transistor circuit by a combination of a plurality of transistors, is disclosed. Among a plurality of the transistors of the circuit unit, the source potential of at least one transistor adapted to turn off during the standby period of the circuit unit is changed. Preferably, the semiconductor integrated circuit is configured to reduce the sub-threshold current flowing between the source and the drain of at least one transistor adapted to turn off during the standby period of the circuit unit by changing the source potential at a timing based on the standby period of the circuit unit in such a manner that a predetermined bias voltage is applied between the gate and the source of the transistor. A method of switching the source potential of at least one transistor in the semiconductor integrated circuit having the configuration described above is also disclosed.
    Type: Application
    Filed: October 5, 1999
    Publication date: October 10, 2002
    Inventors: AYAKO KITAMOTO, MASATO MATSUMIYA, SATOSHI ETO, MASATO TAKITA, TOSHIKAZU NAKAMURA, HIDEKI KANOU, KUNINORI KAWABATA, MASATOMO HASEGAWA, TORU KOGA, YUKI ISHII
  • Patent number: 6421292
    Abstract: In the semiconductor memory, a refresh signal is generated and the refresh operation is performed based on the refresh signal. Parity is generated when data is written and the generated parity is stored. When the refresh operation and a usual data read or write operation overlap, data in a memory cell which cannot be read because the refresh operation is given priority is determined based on the parity. Data which cannot be written because the refresh operation is given priority is held temporarily in a write data buffer. When the refresh operation is not overlapped for the usual data read or write operation, the data held in the write data buffer is rewritten in a corresponding memory cell.
    Type: Grant
    Filed: June 28, 2001
    Date of Patent: July 16, 2002
    Assignee: Fujitsu Limited
    Inventors: Ayako Kitamoto, Masato Matsumiya, Shinichi Yamada, Masato Takita
  • Publication number: 20020067649
    Abstract: In the semiconductor memory, a refresh signal is generated and the refresh operation is performed based on there fresh signal. Parity is generated when data is written and the generated parity is stored. When the refresh operation and a usual data read or write operation are overlapped on each other, data in a memory cell which cannot be read because the refresh operation is given priority is determined based on the parity. Data which cannot be written because the refresh operation is given priority is held temporarily in a write data buffer. When the refresh operation is not overlapped on the usual data read or write operation, the data held in the write data buffer is rewritten in a corresponding memory cell.
    Type: Application
    Filed: June 28, 2001
    Publication date: June 6, 2002
    Applicant: FUJITSU LIMITED
    Inventors: Ayako Kitamoto, Masato Matsumiya, Shinichi Yamada, Masato Takita
  • Publication number: 20020054525
    Abstract: A semiconductor memory device includes a core area formed of memory blocks each having a relaxed sense amplifier arrangement, a data bus including data bus lines corresponding to the memory blocks, a plurality of input/output terminals provided in number corresponding to the data bus lines forming the data bus, and a data path switch circuit provided between the data bus the input/output terminals for providing interconnection paths between the input/output terminals and the data bus lines, wherein the data path switch circuit switches a part of the interconnection paths in response to a switch control signal such that the input/output terminals are connected respectively to predetermined memory cells located at respective, predetermined physical locations in any of the memory blocks.
    Type: Application
    Filed: July 29, 1996
    Publication date: May 9, 2002
    Inventors: SATOSHI ETO, MASATO MATSUMIYA, SHUSAKU YAMAGUCHI, TOSHIKAZU NAKAMURA, HIDEKI KANO, AYAKO KITAMOTO, MITSUHIRO HIGASHIHO