Patents by Inventor Akinori Tahara

Akinori Tahara 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: 6002155
    Abstract: Diodes rows are arranged at interval L in the same direction as that of arrangement of cell rows. Each of the diodes rows has a row of pn junctions each formed on a substrate and arranged along a track vertical to interconnection tracks. The interconnection between cells automatically connect the gates of MOS transistors to the diodes without the need for considering which gate should be connected to the diode. The length of wiring between the gate of MOS transistor and a diode is less than an upper limit value for preventing electrostatic breakdown at a gate oxide in a process of fabricating the semiconductor integrated circuit. Each of the pn junctions may be formed under necessary input signal lines, necessary ground line, the bottom of the drain of MOS transistor or under the power supply line outside of macrocell.
    Type: Grant
    Filed: June 13, 1997
    Date of Patent: December 14, 1999
    Assignee: Fujitsu Limited
    Inventors: Akinori Tahara, Isao Amano
  • Patent number: 5672895
    Abstract: Diodes rows are arranged at interval L in the same direction as that of arrangement of cell rows. Each of the diodes rows has a row of pn junctions each formed on a substrate and arranged along a track vertical to interconnection tracks. The interconnection between cells automatically connect the gates of MOS transistors to the diodes without the need for considering which gate should be connected to the diode. The length of wiring between the gate of MOS transistor and a diode is less than an upper limit value for preventing electrostatic breakdown at a gate oxide in a process of fabricating the semiconductor integrated circuit. Each of the pn junctions may be formed under necessary input signal lines, necessary ground line, the bottom of the drain of MOS transistor or under the power supply line outside of macrocell.
    Type: Grant
    Filed: December 19, 1995
    Date of Patent: September 30, 1997
    Assignee: Fujitsu, Ltd.
    Inventors: Takashi Iida, Satoru Sumi, Hiroshi Shimizu, Akinori Tahara, Isao Amano, Tetsuya Nakajima
  • Patent number: 5500542
    Abstract: Diodes rows are arranged at interval L in the same direction as that of arrangement of cell rows. Each of the diodes rows has a row of pn junctions each formed on a substrate and arranged along a track vertical to interconnection tracks. The interconnection between cells automatically connect the gates of MOS transistors to the diodes without the need for considering which gate should be connected to the diode. The length of wiring between the gate of MOS transistor and a diode is less than an upper limit value for preventing electrostatic breakdown at a gate oxide in a process of fabricating the semiconductor integrated circuit. Each of the pn junctions may be formed under necessary input signal lines, necessary ground line, the bottom of the drain of MOS transistor or under the power supply line outside of macrocell.
    Type: Grant
    Filed: February 14, 1994
    Date of Patent: March 19, 1996
    Assignee: Fujitsu Limited
    Inventors: Takashi Iida, Satoru Sumi, Hiroshi Shimizu, Akinori Tahara, Isao Amano, Tetsuya Nakajima
  • Patent number: 4888623
    Abstract: Electrostatical breakage of a semiconductor device, including an epitaxial layer and a buried layer thereunder, connected to an outer signal terminal, can be prevented by forming an impurity region in the epitaxial layer so as to form a PN junction between the buried layer and the impurity region. The impurity region is connected to a power source or ground.
    Type: Grant
    Filed: October 12, 1988
    Date of Patent: December 19, 1989
    Assignee: Fujitsu Limited
    Inventors: Hiromu Enomoto, Yasushi Yasuda, Yoshiki Shimauchi, Akinori Tahara
  • Patent number: 4810908
    Abstract: A semiconductor logic circuit comprises a clock driver circuit and a clocked circuit which carries out a clocked operation responsive to an output of the clock driver circuit, where an output logic amplitude of the clock driver circuit is set to a value which is greater than an internal logic amplitude of the clocked circuit and is less than or equal to four times the internal logic amplitude of the clocked circuit.
    Type: Grant
    Filed: November 25, 1987
    Date of Patent: March 7, 1989
    Inventors: Hirokazu Suzuki, Akinori Tahara, Shinji Saito
  • Patent number: 4774620
    Abstract: A logic circuit which reduces occurrence of breakdown of the pull-down transistor and pull-up transistor in the output stage when a high voltage is applied to the power supply line and ensures high voltage resistance. The logic circuit controls a pull-up transistor provided between a first power supply and an output terminal which turns ON and OFF in accordance with a collector voltage of a phase splitter transistor and controls the pull-down transistor provided between the second power supply and output terminal with an emitter voltage. Breakdown of the pull-down and pull-up transistors can be reduced and a high voltage resistance ensured by providing a protection circuit which discharges the base of the pull-down transistor and turns OFF the pull-down transistor by detecting when a voltage difference between the first power supply and the second power supply exceeds a specified value.
    Type: Grant
    Filed: September 17, 1987
    Date of Patent: September 27, 1988
    Assignee: Fujitsu Limited
    Inventors: Hiromu Enomoto, Yasushi Yasuda, Masao Kumagai, Akinori Tahara
  • Patent number: 4703202
    Abstract: A gate circuit used for controlling an interface circuit in a microcomputer system, including a first-stage gate circuit, a second-stage gate circuit, and a control device connected between the first-stage gate circuit and the second-stage gate circuit. The first-stage gate circuit outputs an inverted strobe signal to the interface circuit, and the second-stage gate circuit outputs a non-inverted strobe signal to the interface circuit. Although there is a time lag in the changeover timing of these strobe signals, this time lag is reduced by connected the diode between the first-stage gate circuit and the second-stage gate circuit.
    Type: Grant
    Filed: February 11, 1985
    Date of Patent: October 27, 1987
    Assignee: Fujitsu Limited
    Inventors: Hiromu Enomoto, Yasushi Yasuda, Akinori Tahara, Masao Kumagai
  • Patent number: 4680600
    Abstract: A semiconductor device such as a TTL-type integrated circuit device which has an input protection circuit for each inner circuit, e.g., each TT logic gate. The input protection circuit is formed on a semiconductor substrate of a first conductivity type, and includes a first impurity region having a second conductivity type connected to an external terminal and an island-shape formed on the semiconductor substrate surrounded by an isolation region having the first conductivity type. The device also includes a clamp diode formed on an electrode layer contacting with the first impurity region. The device further includes a PN junction type protection diode formed on a second impurity region having the first conductivity type; the protection diode crosses the first impurity region between the clamp diode and a portion of the first impurity region connected to the external terminal and reaches the isolation region.
    Type: Grant
    Filed: October 21, 1986
    Date of Patent: July 14, 1987
    Assignee: Fujitsu Limited
    Inventors: Akinori Tahara, Hiromu Enomoto, Yasushi Yasuda
  • Patent number: 4567380
    Abstract: A level shift element is connected between a transistor (Tr.sub.5) which is used to determine a threshold level when the input voltage falls and a diode (D.sub.3) is connected between an input terminal and an output control transistor (Tr.sub.2) to discharge the base of the output control transistor. The level shift element comprises a diode connected in the forward direction or a resistor.
    Type: Grant
    Filed: June 24, 1983
    Date of Patent: January 28, 1986
    Assignee: Fujitsu Limited
    Inventors: Yasushi Yasuda, Hiromu Enomoto, Yoshiki Shimauchi, Akinori Tahara