Patents by Inventor Yasuharu Sato

Yasuharu Sato 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: 6961830
    Abstract: A semiconductor memory device has a burst write mode in which predetermined plural command signals are input through a plurality of command pads and a mask control operation in the burst write mode is performed in response to the command signals. Therefore, the mask control in burst write mode is increased in speed to give an improved data transfer rate.
    Type: Grant
    Filed: December 24, 2002
    Date of Patent: November 1, 2005
    Assignee: Fujitsu Limited
    Inventors: Hitoshi Ikeda, Yasuharu Sato, Takaaki Suzuki, Toshiya Uchida, Kotoku Sato
  • Publication number: 20050218432
    Abstract: In a semiconductor apparatus of the present invention, a plurality of circuit components are provided. A first bus interconnects the circuit components. A second bus interconnects the circuit components. A switching unit outputs a select signal that causes each circuit component to select one of the first bus and the second bus when transmitting a signal from one of the circuit components to another. The second bus has a size larger than a size of the first bus.
    Type: Application
    Filed: June 3, 2005
    Publication date: October 6, 2005
    Inventors: Yasurou Matsuzaki, Yasuharu Sato, Tadao Aikawa, Masafumi Yamazaki, Takaaki Suzuki
  • Patent number: 6789209
    Abstract: In a semiconductor integrated circuit device operating in synchronism with a clock supplied from the outside of the device, there is provided a circuit generating, from the clock, an output strobe signal for outputting data from the device and outputting the output strobe signal to the outside of the device.
    Type: Grant
    Filed: July 13, 2000
    Date of Patent: September 7, 2004
    Assignee: Fujitsu Limited
    Inventors: Takaaki Suzuki, Yasuharu Sato
  • Patent number: 6771108
    Abstract: An input circuit has an input buffer and a detection circuit. The input buffer receives an external signal and outputs an internal signal. The detection circuit detects whether or not the external signal is provided. The input buffer outputs the internal signal when an output of the detection circuit indicates that the external signal is provided. This arrangement shortens the lock-on time of an internal circuit (synchronous circuit).
    Type: Grant
    Filed: May 23, 2002
    Date of Patent: August 3, 2004
    Assignee: Fujitsu Limited
    Inventors: Kenichi Kawasaki, Yasuharu Sato, Yasurou Matsuzaki, Takaaki Suzuki
  • Patent number: 6727533
    Abstract: In a semiconductor apparatus of the present invention, a plurality of circuit components are provided. A first bus interconnects the circuit components. A second bus interconnects the circuit components. A switching unit outputs a select signal that causes each circuit component to select one of the first bus and the second bus when transmitting a signal from one of the circuit components to another. The second bus has a size larger than a size of the first bus.
    Type: Grant
    Filed: September 21, 2001
    Date of Patent: April 27, 2004
    Assignee: Fujitsu Limited
    Inventors: Yasurou Matsuzaki, Yasuharu Sato, Tadao Aikawa, Masafumi Yamazaki, Takaaki Suzuki
  • Patent number: 6721910
    Abstract: A synchronous DRAM (SDRAM) or a fast cycle RAM (FCRAM) includes capacitors connected by switches to a signal wire. The switches are controlled to connect and disconnect the capacitors to the signal wire. In a test mode, the transmission time of a control signal is tested by connecting various combinations of the capacitors to the signal wire, and then measuring the signal timing. The signal timing of the memory device can be controlled by selecting which and how many of the capacitors are connected to the signal wire.
    Type: Grant
    Filed: September 21, 1999
    Date of Patent: April 13, 2004
    Assignee: Fujitsu Limited
    Inventors: Kazuhiro Ninomiya, Shinya Fujioka, Yasuharu Sato
  • Patent number: 6715115
    Abstract: A semiconductor device including a parallel to serial conversion circuit that receives first through nth data (where n is an integer greater than or equal to 2), together with (n+1)th data, in parallel to each other, and that outputs the first through nth data in series in this order via first through nth paths in a first operating mode, while it outputs the (n+1)th data via one of the second through nth paths in a second operation mode. An output control circuit is connected to the parallel to serial conversion circuit via the first through nth paths, the output control circuit successively outputting the first through nth data in the first operating mode, and outputting only the (n+1)th data supplied from the parallel to serial conversion circuit in the second operating mode.
    Type: Grant
    Filed: July 13, 2000
    Date of Patent: March 30, 2004
    Assignee: Fujitsu Limited
    Inventors: Tadao Aikawa, Yasuharu Sato
  • Publication number: 20030177424
    Abstract: A synchronous DRAM (SDRAM) or a fast cycle RAM (FCRAM) includes capacitors connected by switches to a signal wire. The switches are controlled to connect and disconnect the capacitors to the signal wire. In a test mode, various combinations of the capacitors are connected to the signal wire and the signal timing is then measured. The signal timing of the memory device can be controlled by selecting which and how many of the capacitors are connected to the signal wire.
    Type: Application
    Filed: September 21, 1999
    Publication date: September 18, 2003
    Inventors: KAZUHIRO NINOMIYA, SHINYA FUJIOKA, YASUHARU SATO
  • Publication number: 20030135707
    Abstract: A semiconductor memory device has a burst write mode in which predetermined plural command signals are input through a plurality of command pads and a mask control operation in the burst write mode is performed in response to the command signals. Therefore, the mask control in burst write mode is increased in speed to give an improved data transfer rate.
    Type: Application
    Filed: December 24, 2002
    Publication date: July 17, 2003
    Applicant: FUJITSU LIMITED
    Inventors: Hitoshi Ikeda, Yasuharu Sato, Takaaki Suzuki, Toshiya Uchida, Kotoku Sato
  • Patent number: 6594770
    Abstract: A semiconductor integrated circuit device includes a power-down generating circuit which generates a power-down control signal in response to a power-down signal externally supplied, a clock generating circuit which receives an external clock for generating internal clocks and is inactivated in response to the power-down signal, a chip select circuit which generates an input enable signal in response to a chip select signal externally supplied and is inactivated in response to the power-down signal, and an input circuit which receives an input signal externally supplied in synchronism with an internal clock.
    Type: Grant
    Filed: November 30, 1999
    Date of Patent: July 15, 2003
    Assignee: Fujitsu Limited
    Inventors: Yasuharu Sato, Kenichi Kawasaki
  • Publication number: 20030062942
    Abstract: An input circuit has an input buffer and a detection circuit. The input buffer receives an external signal and outputs an internal signal. The detection circuit detects whether or not the external signal is provided. The input buffer outputs the internal signal when an output of the detection circuit indicates that the external signal is provided. This arrangement shortens the lock-on time of an internal circuit (synchronous circuit).
    Type: Application
    Filed: May 23, 2002
    Publication date: April 3, 2003
    Applicant: Fujitsu Limited
    Inventors: Kenichi Kawasaki, Yasuharu Sato, Yasurou Matsuzaki, Takaaki Suzuki
  • Patent number: 6535965
    Abstract: A semiconductor memory device has a burst write mode in which predetermined plural command signals are input through a plurality of command pads and a mask control operation in the burst write mode is performed in response to the command signals. Therefore, the mask control in burst write mode is increased in speed to give an improved data transfer rate.
    Type: Grant
    Filed: April 27, 2000
    Date of Patent: March 18, 2003
    Assignee: Fujitsu Limited
    Inventors: Hitoshi Ikeda, Yasuharu Sato, Takaaki Suzuki, Toshiya Uchida, Kotoku Sato
  • Patent number: 6522182
    Abstract: In the present invention, an external power source supplied to an integrated circuit device is divided into a first external power source for the DLL circuit and a second external power source for circuits other than the DLL circuit. According to the present invention, it is arranged that power source noise generated in the second external power source cannot be transmitted to the variable delay circuit by utilizing the first external power source preferably for the variable delay circuit of the DLL circuit and even more preferably for its delay unit. Also, preferably, it is arranged that power source noise generated in the second external power source cannot be transmitted to the phase coincidence detection unit by utilizing the first power source for the phase coincidence detection unit in the phase comparison circuit of the DLL circuit.
    Type: Grant
    Filed: August 27, 1999
    Date of Patent: February 18, 2003
    Assignee: Fujitsu Limited
    Inventors: Hiroyoshi Tomita, Naoharu Shinozaki, Nobutaka Taniguchi, Waichirou Fujieda, Yasuharu Sato, Kenichi Kawasaki, Masafumi Yamazaki, Kazuhiro Ninomiya
  • Patent number: 6498522
    Abstract: The invention relates to a clock synchronous type semiconductor device that accepts an input signal inputted from the exterior in synchronization with a clock signal. The semiconductor device according to the invention includes an input signal receiving unit that receives an input signal inputted from the exterior, where the receiving is done in synchronization with a clock signal; a clock timing selecting unit for outputting a clock selecting signal; and a clock generating unit that, in response to receiving a clock selecting signal and an external clock signal, generates a clock signal at a predetermined timing which corresponds to a signal level of the clock selecting signal, and outputs the clock signal to the input signal receiving unit, wherein it is possible to securely accept an input signal regardless of the frequency of the external clock signal.
    Type: Grant
    Filed: April 12, 2001
    Date of Patent: December 24, 2002
    Assignee: Fujitsu Limited
    Inventors: Hitoshi Ikeda, Shinya Fujioka, Yasuharu Sato, Yasurou Matsuzaki
  • Patent number: 6498524
    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 7, 2000
    Date of Patent: December 24, 2002
    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: 6496430
    Abstract: A semiconductor memory circuit includes a plurality of memory cell arrays arranged in rows and columns. A decoder circuit selects a predetermined number of memory cell arrays from among the plurality of the memory cell arrays. Sense amplifiers sense data read from selected memory cell arrays. The plurality of memory cell arrays are grouped into a first type of memory cell arrays each having a redundant memory cell and a second type of memory cell arrays each having no redundant memory cell.
    Type: Grant
    Filed: April 25, 2002
    Date of Patent: December 17, 2002
    Assignee: Fujitsu Limited
    Inventors: Tadao Aikawa, Takaaki Suzuki, Yasuharu Sato, Hiroyuki Kobayashi
  • Patent number: 6459641
    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: April 16, 2001
    Date of Patent: October 1, 2002
    Assignee: Fujitsu Limited
    Inventors: Shinya Fujioka, Masao Taguchi, Waichirou Fujieda, Yasuharu Sato, Takaaki Suzuki, Tadao Aikawa, Takayuki Nagasawa
  • Publication number: 20020114201
    Abstract: A semiconductor memory circuit includes a plurality of memory cell arrays arranged in rows and columns. A decoder circuit selects a predetermined number of memory cell arrays from among the plurality of the memory cell arrays. Sense amplifiers sense data read from selected memory cell arrays. The plurality of memory cell arrays are grouped into a first type of memory cell arrays each having a redundant memory cell and a second type of memory cell arrays each having no redundant memory cell.
    Type: Application
    Filed: April 25, 2002
    Publication date: August 22, 2002
    Applicant: Fujitsu Limited
    Inventors: Tadao Aikawa, Takaaki Suzuki, Yasuharu Sato, Hiroyuki Kobayashi
  • Patent number: 6433607
    Abstract: An input circuit has an input buffer and a detection circuit. The input buffer receives an external signal and outputs an internal signal. The detection circuit detects whether or not the external signal is provided. The input buffer outputs the internal signal when an output of the detection circuit indicates that the external signal is provided. This arrangement shortens the lock-on time of an internal circuit (synchronous circuit).
    Type: Grant
    Filed: June 25, 1999
    Date of Patent: August 13, 2002
    Assignee: Fujitsu Limited
    Inventors: Kenichi Kawasaki, Yasuharu Sato, Yasurou Matsuzaki, Takaaki Suzuki
  • Patent number: 6427197
    Abstract: The present invention is a memory circuit for writing prescribed numbers of bits of write data, determined according to the burst length, in response to write command, comprising: a first stage for inputting, and then holding, row addresses and column addresses simultaneously with the write command; a second stage having a memory core connected to the first stage via a pipeline switch, wherein the row addresses and column addresses are decoded, and word line and sense amps are activated; a third stage for inputting the write data serially and sending the write data to the memory core in parallel; and a serial data detection circuit for generating write-pipeline control signal for making the pipeline switch conduct, after the prescribed number of bits of write data has been inputted. According to the present invention, in an FCRAM exhibiting a pipeline structure, the memory core in the second stage can be activated after safely fetching the write data in the burst length.
    Type: Grant
    Filed: September 13, 1999
    Date of Patent: July 30, 2002
    Assignee: Fujitsu Limited
    Inventors: Yasuharu Sato, Tadao Aikawa, Shinya Fujioka, Waichiro Fujieda, Hitoshi Ikeda, Hiroyuki Kobayashi