Patents by Inventor Masao Taguchi

Masao Taguchi 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: 6384671
    Abstract: An electronic circuit apparatus having a bus, a plurality of stubs branched from the bus, and a plurality of semiconductor devices having signal input/output terminals connected to the corresponding stubs. The electronic circuit apparatus includes at least one impedance circuit arranged between the bus and at least one of the stubs, and each impedance circuit has a high-pass filter characteristic. Therefore, ringing is suppressed, attenuation in the high-frequency components of a transmission signal is prevented, the definition of the signal is maintained, and transmission frequency and speed are both improved.
    Type: Grant
    Filed: April 3, 2000
    Date of Patent: May 7, 2002
    Assignee: Fujitsu Limited
    Inventors: Masao Taguchi, Satoshi Eto, Yoshinori Okajima
  • Patent number: 6377101
    Abstract: A variable delay circuit includes a first gate having a first delay amount, and a second gate having a second delay amount greater than the first delay amount. A difference between the first delay amount and the second delay time is less than the first delay amount.
    Type: Grant
    Filed: February 22, 2000
    Date of Patent: April 23, 2002
    Assignee: Fujitsu Limited
    Inventors: Satoshi Eto, Masao Taguchi, Masato Matsumiya, Toshikazu Nakamura, Masato Takita, Mitsuhiro Higashiho, Toru Koga, Hideki Kano, Ayako Kitamoto, Kuninori Kawabata, Koichi Nishimura, Yoshinori Okajima
  • Publication number: 20020021157
    Abstract: A variable delay circuit includes a first gate having a first delay amount, and a second gate having a second delay amount greater than the first delay amount. A difference between the first delay amount and the second delay time is less than the first delay amount.
    Type: Application
    Filed: February 22, 2000
    Publication date: February 21, 2002
    Inventors: Satoshi Eto, Masao Taguchi, Masato Matsumiya, Toshikazu Nakamura, Masato Takita, Mitsuhiro Higashiho, Toru Koga, Hideki Kano, Ayako Kitamoto, Kuninori Kawabata, Koichi Nishimura, Yoshinori Okajima
  • Patent number: 6344765
    Abstract: A signal-transmission system includes signal-transmission lines connected to a terminal voltage via terminal resistances, open-drain-type transistors outputting signals to the signal-transmission lines, branch lines stemming from the signal-transmission lines to connect the open-drain-type transistors with the signal-transmission lines, and insertion resistances inserted in the branch lines in proximity of the signal-transmission lines.
    Type: Grant
    Filed: December 16, 1999
    Date of Patent: February 5, 2002
    Assignee: Fujitsu Limited
    Inventor: Masao Taguchi
  • Publication number: 20020006071
    Abstract: A semiconductor memory device includes an SRAM provided on a chip, the SRAM including an SRAM cell array. A DRAM is provided on the chip, the DRAM including a DRAM cell array. An address input circuit receives an address signal, the address signal having a first portion and a second portion, the first portion carrying a unique value of row-column address information provided to access one of memory locations in one of the SRAM and DRAM cell arrays, the second portion carrying a unique value of SRAM/DRAM address information provided to select one of the SRAM and the DRAM.
    Type: Application
    Filed: July 31, 2001
    Publication date: January 17, 2002
    Applicant: Fujitsu Limited
    Inventors: Hitoshi Ikeda, Akihiro Funyu, Shinya Fujioka, Takaaki Suzuki, Masao Taguchi, Kimiaki Satoh, Kotoku Sato
  • Publication number: 20020000847
    Abstract: A signal-transmission system includes signal-transmission lines connected to a terminal voltage via terminal resistances, open-drain-type transistors outputting signals to the signal-transmission lines, branch lines stemming from the signal-transmission lines to connect the open-drain-type transistors with the signal-transmission lines, and insertion resistances inserted in the branch lines in proximity of the signal-transmission lines.
    Type: Application
    Filed: December 16, 1999
    Publication date: January 3, 2002
    Inventor: MASAO TAGUCHI
  • Patent number: 6333660
    Abstract: A semiconductor device for generating first and second internal clocks complementary with each other from an external clock and usable for both a system of a type using a complementary clock and a system of a type generating a 180° phase clock internally, is disclosed. A first clock input circuit (buffer) is supplied with a first external clock and outputs a first internal clock. A second clock input circuit (buffer) is supplied with a second external clock complementary with the first external clock and outputs a second clock. A ½ phase clock generating circuit generates a ½ phase shift signal 180° out of phase with the first internal clock. A second external clock state detection circuit judges whether the second external clock is input to the second clock input buffer.
    Type: Grant
    Filed: February 12, 2001
    Date of Patent: December 25, 2001
    Assignee: Fujitsu Limited
    Inventors: Masao Taguchi, Hiroyoshi Tomita, Yasurou Matsuzaki
  • Patent number: 6329871
    Abstract: A reference voltage generation circuit includes: a load unit having one end thereof connected to a higher voltage power supply line; an enhancement type n-channel MIS transistor having a drain thereof connected to the other end of the load unit, and a source thereof connected to a lower voltage power supply line; and a source follower circuit using a MIS transistor as a driving element, the source follower circuit having an input end thereof connected to the drain of the n-channel MIS transistor and having an output end thereof connected to a gate of the n-channel MIS transistor. A reference voltage is obtained at the drain of the n-channel MIS transistor. By the constitution, it is possible to obtain a stable reference voltage, and to incorporate the reference voltage generation circuit into an integrated circuit produced by integrating MIS transistors, without introducing an increase in production processes. It is also possible to reduce a consumed current of the reference voltage generation circuit.
    Type: Grant
    Filed: December 22, 2000
    Date of Patent: December 11, 2001
    Assignee: Fujitsu Limited
    Inventor: Masao Taguchi
  • Patent number: 6298004
    Abstract: Disclosed is a semiconductor device for outputting an output signal with a given phase held relative to an external clock despite a difference in characteristic, a change in temperature, and a fluctuation in supply voltage. The semiconductor device comprises an input circuit for inputting the external clock and outputting a reference signal, an output circuit for receiving an output timing signal and outputting an output signal according to the timing of the output timing signal, and an output timing control circuit for controlling the output timing so that the output signal exhibits a given phase relative to the external clock.
    Type: Grant
    Filed: July 15, 1997
    Date of Patent: October 2, 2001
    Assignee: Fujitsu Limited
    Inventors: Kenichi Kawasaki, Yasuharu Sato, Terumasa Kitahara, Masao Nakano, Masao Taguchi, Yoshihiro Takemae, Yasurou Matsuzaki, Koichi Nishimura, Yoshinori Okajima, Naoharu Shinozaki, Hiroko Douchi
  • Patent number: 6292426
    Abstract: A semiconductor memory device includes an SRAM provided on a chip, the SRAM including an SRAM cell array. A DRAM is provided on the chip, the DRAM including a DRAM cell array. An address input circuit receives an address signal, the address signal having a first portion and a second portion, the first portion carrying a unique value of row-column address information provided to access one of memory locations in one of the SRAM and DRAM cell arrays, the second portion carrying a unique value of SRAM/DRAM address information provided to select one of the SRAM and the DRAM.
    Type: Grant
    Filed: March 21, 2000
    Date of Patent: September 18, 2001
    Assignee: Fujitsu Limited
    Inventors: Hitoshi Ikeda, Akihiro Funyu, Shinya Fujioka, Takaaki Suzuki, Masao Taguchi, Kimiaki Satoh, Kotoku Sato
  • Publication number: 20010021140
    Abstract: The present invention is aimed at providing a semiconductor memory device which performs a row-address pipe-line operation in accessing different row addresses so as to achieve high-speed access. The semiconductor memory device according to the present invention includes a plurality of sense-amplifiers which store data when the data is received via bit lines from memory cells corresponding to a selected word line, a column decoder which reads parallel data of a plurality of bits from selected sense amplifiers by simultaneously selecting a plurality of column gates in response to a column address, a data-conversion unit which converts the parallel data into serial data, and a precharge-signal-generation unit which generates an internal precharge signal a first delay-time period after generation of a row-access signal for selecting the selected word line so as to reset the bit lines and said plurality of sense-amplifiers.
    Type: Application
    Filed: April 16, 2001
    Publication date: September 13, 2001
    Applicant: Fujitsu Limited
    Inventors: Shinya Fujioka, Masao Taguchi, Waichirou Fujieda, Yasuharu Sato, Takaaki Suzuki, Tadao Aikawa, Takayuki Nagasawa
  • Patent number: 6272069
    Abstract: A data signal is output from an output circuit of a first chip and sent to a data input terminal in the second chip via a data lead line based on an output clock in first chip, which is sent to the second chip. And an input circuit in a second chip receives the data signal and transfers it inside in response to a transfer clock that has been generated from the output clock in the first chip. In synchronism with a single reference clock in the first chip, therefore, a data signal can be transferred to the second chip from the first chip at a high speed.
    Type: Grant
    Filed: January 19, 2001
    Date of Patent: August 7, 2001
    Assignee: Fujitsu Limited
    Inventors: Hiroyoshi Tomita, Yasurou Matsuzaki, Masao Taguchi
  • Publication number: 20010005157
    Abstract: A semiconductor device for generating first and second internal clocks complementary with each other from an external clock and usable for both a system of a type using a complementary clock and a system of a type generating a 180° phase clock internally, is disclosed. A first clock input circuit (buffer) is supplied with a first external clock and outputs a first internal clock. A second clock input circuit (buffer) is supplied with a second external clock complementary with the first external clock and outputs a second clock. A ½ phase clock generating circuit generates a ½ phase shift signal 180° out of phase with the first internal clock. A second external clock state detection circuit judges whether the second external clock is input to the second clock input buffer.
    Type: Application
    Filed: February 12, 2001
    Publication date: June 28, 2001
    Applicant: Fujitsu Limited
    Inventors: Masao Taguchi, Hiroyoshi Tomita, Yasurou Matsuzaki
  • Publication number: 20010005160
    Abstract: A reference voltage generation circuit includes: a load unit having one end thereof connected to a higher voltage power supply line; an enhancement type n-channel MIS transistor having a drain thereof connected to the other end of the load unit, and a source thereof connected to a lower voltage power supply line; and a source follower circuit using a MIS transistor as a driving element, the source follower circuit having an input end thereof connected to the drain of the n-channel MIS transistor and having an output end thereof connected to a gate of the n-channel MIS transistor. A reference voltage is obtained at the drain of the n-channel MIS transistor. By the constitution, it is possible to obtain a stable reference voltage, and to incorporate the reference voltage generation circuit into an integrated circuit produced by integrating MIS transistors, without introducing an increase in production processes. It is also possible to reduce a consumed current of the reference voltage generation circuit.
    Type: Application
    Filed: December 22, 2000
    Publication date: June 28, 2001
    Applicant: Fujitsu Limited
    Inventor: Masao Taguchi
  • Patent number: 6246620
    Abstract: The present invention is aimed at providing a semiconductor memory device which performs a row-address pipe-line operation in accessing different row addresses so as to achieve high-speed access. The semiconductor memory device according to the present invention includes a plurality of sense-amplifiers which store data when the data is received via bit lines from memory cells corresponding to a selected word line, a column decoder which reads parallel data of a plurality of bits from selected sense amplifiers by simultaneously selecting a plurality of column gates in response to a column address, a data-conversion unit which converts the parallel data into serial data, and a precharge-signal-generation unit which generates an internal precharge signal a first delay-time period after generation of a row-access signal for selecting the selected word line so as to reset the bit lines and said plurality of sense-amplifiers.
    Type: Grant
    Filed: March 23, 2000
    Date of Patent: June 12, 2001
    Assignee: Fujitsu Limited
    Inventors: Shinya Fujioka, Masao Taguchi, Waichirou Fujieda, Yasuharu Sato, Takaaki Suzuki, Tadao Aikawa, Takayuki Nagasawa
  • Publication number: 20010002179
    Abstract: A data signal is output from an output circuit of a first chip and sent to a data input terminal in the second chip via a data lead line based on an output clock in first chip, which is sent to the second chip. And an input circuit in a second chip receives the data signal and transfers it inside in response to a transfer clock that has been generated from the output clock in the first chip. In synchronism with a single reference clock in the first chip, therefore, a data signal can be transferred to the second chip from the first chip at a high speed.
    Type: Application
    Filed: January 19, 2001
    Publication date: May 31, 2001
    Applicant: FUJITSU LIMITED
    Inventors: Hiroyoshi Tomita, Yasurou Matsuzaki, Masao Taguchi
  • Patent number: 6225855
    Abstract: A reference voltage generation circuit includes: a load unit having one end thereof connected to a higher voltage power supply line; an enhancement type n-channel MIS transistor having a drain thereof connected to the other end of the load unit, and a source thereof connected to a lower voltage power supply line; and a source follower circuit using a MIS transistor has a driving element, the source follower circuit having an input end thereof connected to the drain of the n-channel MIS transistor and having an output end thereof connected to a gate of the n-channel MIS transistor. A reference voltage is obtained at the drain of the n-channel MIS transistor. By the constitution, it is possible to obtain a stable reference voltage, and to incorporate the reference voltage generation circuit into an integrated circuit produced by integrating MIS transistors, without introducing an increase in production processes. It is also possible to reduce a consumed current of the reference voltage generation circuit.
    Type: Grant
    Filed: September 16, 1998
    Date of Patent: May 1, 2001
    Assignee: Fujitsu Limited
    Inventor: Masao Taguchi
  • Patent number: 6225841
    Abstract: A semiconductor device for generating first and second internal clocks complementary with each other from an external clock and usable for both a system of a type using a complementary clock and a system of a type generating a 180° phase clock internally, is disclosed. A first clock input circuit (buffer) is supplied with a first external clock and outputs a first internal clock. A second clock input circuit (buffer) is supplied with a second external clock complementary with the first external clock and outputs a second clock. A ½ phase clock generating circuit generates a ½ phase shift signal 180° out of phase with the first internal clock. A second external clock state detection circuit judges whether the second external clock is input to the second clock input buffer.
    Type: Grant
    Filed: April 21, 2000
    Date of Patent: May 1, 2001
    Assignee: Fujitsu Limited
    Inventors: Masao Taguchi, Yasurou Matsuzaki, Miki Yanagawa
  • Patent number: 6205082
    Abstract: A data signal is output from an output circuit of a first chip and sent to a data input terminal in the second chip via a data lead line based on an output clock in first chip, which is sent to the second chip. And an input circuit in a second chip receives the data signal and transfers it inside in response to a transfer clock that has been generated from the output clock in the first chip. In synchronism with a single reference clock in the first chip, therefore, a data signal can be transferred to the second chip from the first chip at a high speed.
    Type: Grant
    Filed: May 4, 1999
    Date of Patent: March 20, 2001
    Assignee: Fujitsu Limited
    Inventors: Hiroyoshi Tomita, Yasurou Matsuzaki, Masao Taguchi
  • Patent number: 6201423
    Abstract: Disclosed is a semiconductor device for outputting an output signal with a given phase held relative to an external clock despite a difference in characteristic, a change in temperature, and a fluctuation in supply voltage. The semiconductor device comprises an input circuit for inputting the external clock and outputting a reference signal, an output circuit for receiving an output timing signal and outputting an output signal according to the timing of the output timing signal, and an output timing control circuit for controlling the output timing so that the output signal exhibits a given phase relative to the external clock.
    Type: Grant
    Filed: November 24, 1999
    Date of Patent: March 13, 2001
    Assignee: Fujitsu Limited
    Inventors: Masao Taguchi, Yoshihiro Takemae