Patents by Inventor Atushi Kameyama

Atushi Kameyama 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: 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