Patents by Inventor Yoshio Ohtsuki

Yoshio Ohtsuki 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: 6459327
    Abstract: A feedback controlled substrate bias generator having a substrate bias level sensing circuit, a charge pump circuit and an improved oscillator is disclosed. The substrate bias level sensing circuit is coupled to a semiconductor substrate for sensing a bias voltage of the semiconductor substrate and outputting a control signal in response to the sensed bias voltage. The charge pump circuit is coupled to the semiconductor substrate and the substrate bias level sensing circuit for receiving a clock pulse and the control signal and supplying the bias voltage to the semiconductor substrate in response to the received signals. The improved oscillator is coupled to the charge pump circuit for generating the clock pulse. The improved oscillator has a loop circuit having a plurality of serially and circularly coupled inverters each of which has a source terminal applied to voltage from a voltage source, an input terminal for receiving an input signal and an output terminal for outputting an output signal.
    Type: Grant
    Filed: December 7, 1992
    Date of Patent: October 1, 2002
    Assignee: Oki Electric Industry Co., Ltd.
    Inventors: Hitoshi Yamada, Tamihiro Ishimura, Yoshio Ohtsuki
  • Patent number: 5517444
    Abstract: In semiconductor memory device having a plurality of memory cell arrays in which a potential difference between a pair of bit lines to which memory cells are connected is amplified by a sense amplifier operating responsive to a sense latch signal on a common node, and the memory cells are connected via a power supply line to a power supply, the adverse effects due to the resistance of the power supply line is eliminated or reduced. This is achieved by coupling a power supply auxiliary line disposed within each memory cell array and a power supply main line disposed along the memory cell arrays by means of a resistive element having a resistance larger than the resistance of the power supply main line from the power supply to the memory cell array located farthest. Alternatively, the common node in each memory cell array is connected to said power supply main line via a resistive element and a sense amplifier drive transistor which is turned on and off by a control signal.
    Type: Grant
    Filed: March 2, 1995
    Date of Patent: May 14, 1996
    Assignee: Oki Electric Industry Co., Ltd.
    Inventors: Tamihiro Ishimura, Masahumi Miyawaki, Yoshio Ohtsuki
  • Patent number: 5321658
    Abstract: In semiconductor memory device having a plurality of memory cell arrays in which a potential difference between a pair of bit lines to which memory cells are connected is amplified by a sense amplifier operating responsive to a sense latch signal on a common node, and the memory cells are connected via a power supply line to a power supply, the adverse effects due to the resistance of the power supply line is eliminated or reduced. This is achieved by coupling a power supply auxiliary line disposed within each memory cell array and a power supply main line disposed along the memory cell arrays by means of a resistive element having a resistance larger than the resistance of the power supply main line from the power supply to the memory cell array located farthest. Alternatively, the common node in each memory cell array is connected to said power supply main line via a resistive element and a sense amplifier drive transistor which is turned on and off by a control signal.
    Type: Grant
    Filed: May 20, 1991
    Date of Patent: June 14, 1994
    Assignee: Oki Electric Industry Co., Ltd.
    Inventors: Tamihiro Ishimura, Masahumi Miyawaki, Yoshio Ohtsuki
  • Patent number: 5260904
    Abstract: A data bus clamping circuit for use in a semiconductor memory device includes a memory cell array for storing data, a row address decoder for decoding row address signals taken in by a row address strobe signal to select memory cells in a row direction of the memory cell array, a column address decoder for decoding column address signals based on a column address decoder enabling signal to select memory cells in a column direction of the memory cell array, complementary data buses for transmitting data read out from the memory cell array, a data bus pull-up circuit for pulling up the complementary data buses, and a differential amplification type of readout circuit for amplifying on a differential basis data on the complementary data buses to output readout data.
    Type: Grant
    Filed: November 26, 1991
    Date of Patent: November 9, 1993
    Assignee: Oki Electric Industry Co., Ltd.
    Inventors: Masahumi Miyawaki, Tamihiro Ishimura, Yoshio Ohtsuki
  • Patent number: 5237536
    Abstract: In a semiconductor memory device comprising a plurality of groups of memory cell blocks, a plurality of groups of predecoder input signal lines respectively connected to predecoders in the memory cell block groups, and a predecoder input signal generator. The predecoder input signal generator sets the predecoder input signal lines of the selected group to either the high level or the low level in accordance with the external address information. A clamping circuit is provided to clamp substantially half the predecoder input signal lines of the unselected group to the high level, and the remaining half to the low level. Because one half of the predecoder input signal lines of the unselected group is clamped to the high level and the remaining half of the unselected group is clamped to the low level, their line loads serve as decoupling capacitors both at the charging and discharging of the predecoder input signal lines of the selected group, so that the power supply noise is reduced in both occasions.
    Type: Grant
    Filed: January 29, 1991
    Date of Patent: August 17, 1993
    Assignee: Oki Electric Industry Co., Ltd.
    Inventor: Yoshio Ohtsuki
  • Patent number: 5091886
    Abstract: A data bus clamping circuit for use in a semiconductor memory device includes a memory cell array for storing data, a row address decoder for decoding row address signals taken in by a row address strobe signal to select memory cells in a row direction of the memory cell array, a column address decoder for decoding column address signals based on a column address decoder enabling signal to select memory cells in a column direction of the memory cell array, complementary data buses for transmitting data read out from the memory cell array, a data bus pull-up circuit for pulling up the complementary data buses, and a differential amplification type of readout circuit for amplifying on a differential basis data on the complementary data buses to output readout data.
    Type: Grant
    Filed: May 28, 1991
    Date of Patent: February 25, 1992
    Assignee: Oki Electric Industry Co., Ltd.
    Inventors: Masahumi Miyawaki, Tamihiro Ishimura, Yoshio Ohtsuki