Patents by Inventor Shigeo Ohshima

Shigeo Ohshima 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: 20030142577
    Abstract: A synchronous semiconductor memory device includes a plurality of memory banks which read data from memory cells and write data into the memory cells, a command decoder circuit which receives a command, detects whether the command is a read command or a write command, and, when detecting a read command or a write command, outputs a first control signal that enables a read operation or a write operation in the plurality of memory banks, bank select circuits which activate a second control signal to activate each of the memory banks, and bank timer circuits which deactivate the activated second control signal and perform control in such a manner that the timing with which the second control signal is deactivated in a test mode differs from that in a normal mode.
    Type: Application
    Filed: January 28, 2003
    Publication date: July 31, 2003
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Noriyasu Kumazaki, Shigeo Ohshima, Kazuaki Kawaguchi
  • Publication number: 20030123297
    Abstract: An input data register for latching write data is arranged in a position near a memory cell array of a memory core section. The input data register is arranged on the upstream side of a data path used for writing data into a memory cell. Write data input to a data pin which is arranged in the end position on the downstream side is latched in the input data register via a data input buffer, serial/parallel converting circuit and write data line. Data latched in the input data register is written into a memory cell via a DQ write driver, data line pair, I/O gate and bit line pair in a next write cycle.
    Type: Application
    Filed: February 18, 2003
    Publication date: July 3, 2003
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Shigeo Ohshima, Hiroyuki Ohtake, Katsumi Abe
  • Publication number: 20030117887
    Abstract: A row access command and column access command are supplied as one packet to an FCRAM in two successive clock cycles in order to shorten random access time and random cycle time. At this time, definition of the read/write operation is made by use of a first command and a decode address of a memory cell array is fetched in response to the first command. When the decode address of the memory cell array is fetched in response to the first command, command control pins of the conventional SDR/DDR-SDRAM are used as address pins.
    Type: Application
    Filed: December 27, 2002
    Publication date: June 26, 2003
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Shigeo Ohshima, Nobuo Watanabe
  • Patent number: 6545941
    Abstract: A clock synchronous circuit is stopped or started in accordance with the situation. More specifically, the clock synchronous circuit is stopped when no synchronous clock is necessary or in modes, such as a standby mode, bank active mode, refresh mode, and write mode, other than a read mode. In the read mode, the clock synchronous circuit is operated because a synchronous clock is necessary to output data. In the read mode, the number of clocks, i.e., CL, required from the time a read command is input to the time data is actually output, is 3 or more, when restarting and preamble of the clock synchronous circuit are taken into consideration.
    Type: Grant
    Filed: September 27, 2001
    Date of Patent: April 8, 2003
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Koji Kato, Shigeo Ohshima
  • Publication number: 20030053362
    Abstract: A synchronous semiconductor memory device has a memory section which includes a memory cell array having a plurality of memory cells and which is capable of a read operation of reading information from the memory cells according to a read command and a write operation of writing information into the memory cells according to a write command. The synchronous semiconductor memory device further has a command sensing circuit which senses whether a first command inputted in synchronization with an external clock signal is the read command or the write command. The synchronous semiconductor memory device further has a bank timer circuit which, when the command sensing circuit has sensed either the read command or the write command, sets the end time of the restore operation of a row address strobe (RAS) and the start time of the precharge operation of the RAS according to the external clock signal.
    Type: Application
    Filed: September 17, 2002
    Publication date: March 20, 2003
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Kazuaki Kawaguchi, Shigeo Ohshima
  • Publication number: 20030047757
    Abstract: A semiconductor integrated circuit, comprising: a first output driving part which outputs a data signal in sync with a reference clock signal; a second output driving part which outputs a data strobe signal prescribing a timing of said data signal; and a driving control part which separately controls driving ability of said first and second output driving parts.
    Type: Application
    Filed: September 12, 2002
    Publication date: March 13, 2003
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Noriyasu Kumazaki, Keiji Maruyama, Shigeo Ohshima
  • Publication number: 20030035335
    Abstract: In an FCRAM having a late write function, when a first command signal indicates “write active”, whether a write operation or an auto-refresh operation is to be performed is determined on the basis of a second command signal. For example, when the second command signal indicates “write”, a write operation for a memory cell is performed by a late write scheme. When the second command signal indicates “auto-refresh”, an auto-refresh operation is performed. In the last write cycle of a write operation immediately preceding this auto-refresh operation, addresses for selecting a memory cell as an object of auto-refresh are predetermined. After data write to a memory cell is completed in the last write cycle, row precharge for auto-refresh is performed. After that, an auto-refresh operation (i.e., a data read operation and a data restore operation) is performed for the selected memory cell.
    Type: Application
    Filed: August 26, 2002
    Publication date: February 20, 2003
    Inventors: Kazuaki Kawaguchi, Shigeo Ohshima
  • Patent number: 6522600
    Abstract: A semiconductor memory device comprises first and second pins, a controller, a first command decoder and a lower-side command decoder. The controller is supplied with a signal indicating that a read command is input and a signal indicating that a write command is input based on the signal input to the first pin. The first command decoder is controlled by an output signal of the controller, defines the readout/write operation by use of the first command, fetches an upper-side decode address of a memory cell array via the second pin and decodes the first command. A lower-side command decoder is controlled by an output signal of the controller, fetches a lower-side decode address of the memory cell array via the control pin in response to the second command, decodes the lower-side command, and outputs a lower address latch command, mode register set command and auto-refresh command.
    Type: Grant
    Filed: June 4, 2002
    Date of Patent: February 18, 2003
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Shigeo Ohshima, Nobuo Watanabe
  • Patent number: 6483772
    Abstract: A specifying circuit specifies either the first masking method or the second masking method. A first generation circuit generates a signal corresponding to the first method. A second generation circuit generates a signal corresponding to the second method. A third generation circuit generates a write pulse signal on the basis of the output signal of the first generation circuit in response to the specification of the first masking method made by the specifying circuit and on the basis of the output signal of the second generation circuit in response to the specification of the second masking method made by the specifying circuit.
    Type: Grant
    Filed: September 12, 2001
    Date of Patent: November 19, 2002
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Susumu Ozawa, Shigeo Ohshima, Katsumi Abe
  • Publication number: 20020149993
    Abstract: A row access command and column access command are supplied as one packet to an FCRAM in two successive clock cycles in order to shorten random access time and random cycle time. At this time, definition of the read/write operation is made by use of a first command and a decode address of a memory cell array is fetched in response to the first command. When the decode address of the memory cell array is fetched in response to the first command, command control pins of the conventional SDR/DDR-SDRAM are used as address pins.
    Type: Application
    Filed: June 4, 2002
    Publication date: October 17, 2002
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Shigeo Ohshima, Nobuo Watanabe
  • Patent number: 6463007
    Abstract: A synchronous semiconductor memory device such as SDRAM easy in timing adjustment of column selection and capable of reducing cycle time and access time to be minimum value without reducing access margin is provided. The synchronous semiconductor memory device includes a memory cell array constituted in a matrix form, a command decoder and an address buffer operative in synchronism with the leading end of clock signal, a row decoder for decoding row address to select word line of the memory cell, a column control signal generating circuit for generating a column control signal, and a column decoder for taking thereinto column address taken in by the address buffer by a column address taking-in signal generated from the command decoder in synchronism with the leading end of the clock signal to allow a column select signal line to be active.
    Type: Grant
    Filed: August 23, 2001
    Date of Patent: October 8, 2002
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiroyuki Ohtake, Shigeo Ohshima
  • Patent number: 6426915
    Abstract: A row access command and column access command are supplied as one packet to an FCRAM in two successive clock cycles in order to shorten random access time and random cycle time. At this time, definition of the read/write operation is made by use of a first command and a decode address of a memory cell array is fetched in response to the first command. When the decode address of the memory cell array is fetched in response to the first command, command control pins of the conventional SDR/DDR-SDRAM are used as address pins.
    Type: Grant
    Filed: December 27, 2000
    Date of Patent: July 30, 2002
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Shigeo Ohshima, Nobuo Watanabe
  • Publication number: 20020039326
    Abstract: A clock synchronous circuit is stopped or started in accordance with the situation. More specifically, the clock synchronous circuit is stopped when no synchronous clock is necessary or in modes, such as a standby mode, bank active mode, refresh mode, and write mode, other than a read mode. In the read mode, the clock synchronous circuit is operated because a synchronous clock is necessary to output data. In the read mode, the number of clocks, i.e., CL, required from the time a read command is input to the time data is actually output, is 3 or more, when restarting and preamble of the clock synchronous circuit are taken into consideration.
    Type: Application
    Filed: September 27, 2001
    Publication date: April 4, 2002
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Koji Kato, Shigeo Ohshima
  • Publication number: 20020038914
    Abstract: A semiconductor integrated circuit device comprises a semiconductor chip, a wiring provided in the semiconductor chip and electrically connected to an external pin and a pin capacitance adjustment circuit configured to variably adjust a capacitance of the wiring.
    Type: Application
    Filed: September 26, 2001
    Publication date: April 4, 2002
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Keiji Maruyama, Shigeo Ohshima
  • Publication number: 20020036301
    Abstract: A semiconductor integrated circuit device comprises a register circuit receives a data signal, a delay adjustment circuit receives an output of the register circuit and a driver circuit receives an output of the delay adjustment circuit. An output timing of the register circuit is controlled by a clock signal. A delay time of the delay adjustment circuit is adjusted by a delay adjustment signal based on the data signal.
    Type: Application
    Filed: September 25, 2001
    Publication date: March 28, 2002
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Katsushi Nagaba, Shigeo Ohshima
  • Publication number: 20020031020
    Abstract: A specifying circuit specifies either the first masking method or the second masking method. A first generation circuit generates a signal corresponding to the first method. A second generation circuit generates a signal corresponding to the second method. A third generation circuit generates a write pulse signal on the basis of the output signal of the first generation circuit in response to the specification of the first masking method made by the specifying circuit and on the basis of the output signal of the second generation circuit in response to the specification of the second masking method made by the specifying circuit.
    Type: Application
    Filed: September 12, 2001
    Publication date: March 14, 2002
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Susumu Ozawa, Shigeo Ohshima, Katsumi Abe
  • Publication number: 20020012263
    Abstract: In the package, a semiconductor chip is accommodated. This semiconductor chip has n pads (n is a natural number). The package has n pins connected to n pads.
    Type: Application
    Filed: July 19, 2001
    Publication date: January 31, 2002
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Shigeo Ohshima, Nobuo Watanabe
  • Publication number: 20020001254
    Abstract: A synchronous semiconductor memory device such as SDRAM easy in timinq adjustment of column selection and capable of reducing cycle time and access time to be minimum value without reducing access margin is provided. The synchronous semiconductor memory device includes a memory cell array constituted in a matrix form, a command decoder and an address buffer operative in synchronism with the leading end of clock signal, a row decoder for decoding row address to select word line of the memory cell, a column control signal generating circuit for generating a column control signal, and a column decoder for taking thereinto column address taken in by the address buffer by a column address taking-in signal generated from the command decoder in synchronism with the leading end of the clock signal to allow a column select signal line to be active.
    Type: Application
    Filed: August 23, 2001
    Publication date: January 3, 2002
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Hiroyuki Ohtake, Shigeo Ohshima
  • Patent number: 6313676
    Abstract: A semiconductor integrated circuit has an internal clock signal generator circuit and a data input/output circuit. The internal clock signal generator circuit includes a clock receiver, a synchronous delay control circuit, a clock driver, an output control circuit, a delay monitor, and a control signal generator circuit. Accordingly, in a delay measuring mode, a delay in the input signal is set in the delay monitor based on a measurement start signal and a measurement stop signal. After completion of the delay measuring mode, the delay monitor causes the signal CLK, outputted from the clock receiver, to lag behind by a delay set in the delay measuring mode. Further, the delay monitor outputs the delayed signal to the synchronous delay control circuit.
    Type: Grant
    Filed: March 16, 2000
    Date of Patent: November 6, 2001
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Katsumi Abe, Masahiro Kamoshida, Shigeo Ohshima
  • Publication number: 20010030900
    Abstract: In an FCRAM having a late write function, when a first command signal indicates “write active”, whether a write operation or an auto-refresh operation is to be performed is determined on the basis of a second command signal. For example, when the second command signal indicates “write”, a write operation for a memory cell is performed by a late write scheme. When the second command signal indicates “auto-refresh”, an auto-refresh operation is performed. In the last write cycle of a write operation immediately preceding this auto-refresh operation, addresses for selecting a memory cell as an object of auto-refresh are predetermined. After data write to a memory cell is completed in the last write cycle, row precharge for auto-refresh is performed. After that, an auto-refresh operation (i.e., a data read operation and a data restore operation) is performed for the selected memory cell.
    Type: Application
    Filed: March 23, 2001
    Publication date: October 18, 2001
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Kazuaki Kawaguchi, Shigeo Ohshima