Patents by Inventor Yasuo Ikawa

Yasuo Ikawa 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: 4764897
    Abstract: A GaAs (gallium arsenide) semiconductor memory device includes a plurality of memory cells connected in a matrix form by employing a plurality of bit lines and of word lines, and of word line drivers. The memory device is operable under a single power supply. Transfer gates of the memory cells are normally-on type GaAs metal-semiconductor field effect transistors (MESFET's). A parallel circuit including a Schottky diode and a switching GaAs-MESFET is interposed between commonly-connected sources of driver MESFET's of each of the memory cells and the ground line, so that a higher potential of the commonly-connected sources is clamped due to the clamping effect of the Schottky diode when the switching GaAs-MESFET is turned off.
    Type: Grant
    Filed: September 12, 1986
    Date of Patent: August 16, 1988
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Atushi Kameyama, Yasuo Ikawa, Katsue Kawakyu
  • Patent number: 4663646
    Abstract: A gate array integrated circuit in which gate cells are each composed of a DCFL circuit using Schottky-barrier FETs. A plurality of basic gate cells is arrayed in one direction to form a basic cell array, and such basic cell arrays are arranged parallel to each other. VDD lines and GND lines are provided to apply an operating voltage to the basic gate cells. In order to stably operate the gate array integrated circuit of DCFL structure in which the logical amplitude and noise margin are small, the VDD lines and the GND lines are arranged perpendicular to each other such that the number of the basic gate cells which are connected to each of the VDD lines is larger than that of the basic gate cells which are connected to each of the GND lines. According to this layout, the potential difference (voltage drop) developed in the GND lines by operation current is reduced.
    Type: Grant
    Filed: November 26, 1984
    Date of Patent: May 5, 1987
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yasuo Ikawa, Nobuyuki Toyoda, Katsue Kanazawa, Takamaro Mizoguchi, Akimichi Hojo
  • Patent number: 4639621
    Abstract: A gallium arsenide NAND gate is connected between a power source and a ground potential. The gate is comprised of a load transistor of a normally-on type field effect transistor having an output terminal and a drain connected to the power source, a first driver transistor of a normally-off type field effect transistor having a gate electrode as a first input terminal and a source-to-drain current path series-connected to that of the load transistor, and a second driver transistor of two normally-off type field effect transistors having a common gate electrode for a second input terminal and source-to-drain current paths series-connected between the power source and the ground potential through the series-connected first driver transistor and load transistor. The normally-off type field effect transistors are parallel-connected to each other so as to equally constitute a single driver transistor as the second driver transistor.
    Type: Grant
    Filed: December 5, 1985
    Date of Patent: January 27, 1987
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yasuo Ikawa, Katsue Kawakyu, Atushi Kameyama
  • Patent number: 4631686
    Abstract: A programmable semiconductor integrated circuit device is disclosed, which includes different kinds of MSI scale function blocks formed on a substrate. First wiring lines extending in a row direction are connected to input terminals of the function blocks, respectively. Second wiring lines are connected to output terminals of the function blocks, respectively. The second wirings are T-shaped and have respective line components extending in a column direction, with the first wiring lines. Floating gate type field effect transistors are provided, in a matrix manner, at mutually electrically insulated crossing points among the first and second lines.
    Type: Grant
    Filed: August 31, 1984
    Date of Patent: December 23, 1986
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yasuo Ikawa, Tadashi Shibata, Kiyoshi Urui, Misao Miyata, Masahiko Kawamura, Noboru Amano