Patents by Inventor Yoshiki Koyama

Yoshiki Koyama 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: 6545513
    Abstract: A current control circuit controls a gate potential of a transistor to equalize a load current IL with a trapezoidal wave signal Sb. The trapezoidal wave signal Sb increases at a constant gradient when a drive command signal Sa turns into H level. Due to increase of load current IL, the transistor starts operating in a linear region and a gate voltage VGS abruptly increases. A saturation state detecting circuit turns a current saturation signal Sc into L level when the gate voltage VGS exceeds a reference voltage Vr. A trapezoidal wave generating circuit stops increase of trapezoidal wave signal Sb. When drive command signal Sa turns into L level, the trapezoidal wave signal Sb decreases at a constant gradient. The load current IL decreases according to reduction of trapezoidal wave signal Sb.
    Type: Grant
    Filed: May 16, 2002
    Date of Patent: April 8, 2003
    Assignee: Denso Corporation
    Inventors: Masahiro Tsuchida, Nobumasa Ueda, Hiroshi Fujimoto, Yoshiki Koyama
  • Publication number: 20020171455
    Abstract: A current control circuit controls a gate potential of a transistor to equalize a load current IL with a trapezoidal wave signal Sb. The trapezoidal wave signal Sb increases at a constant gradient when a drive command signal Sa turns into H level. Due to increase of load current IL, the transistor starts operating in a linear region and a gate voltage VGS abruptly increases. A saturation state detecting circuit turns a current saturation signal Sc into L level when the gate voltage VGS exceeds a reference voltage Vr. A trapezoidal wave generating circuit stops increase of trapezoidal wave signal Sb. When drive command signal Sa turns into L level, the trapezoidal wave signal Sb decreases at a constant gradient. The load current IL decreases according to reduction of trapezoidal wave signal Sb.
    Type: Application
    Filed: May 16, 2002
    Publication date: November 21, 2002
    Inventors: Masahiro Tsuchida, Nobumasa Ueda, Hiroshi Fujimoto, Yoshiki Koyama
  • Patent number: 6479877
    Abstract: A semiconductor device for a load drive circuit includes a main LDMOS device and a sense LDMOS device that are connected to each other in parallel to form a current mirror circuit. The main LDMOS device and the sense LDMOS device have plural drain cells and plural source cells that are arranged to form a generally square shape as a whole. In the plural drain cells, drain cells of the sense LDMOS device are arranged along a diagonal of the generally square shape.
    Type: Grant
    Filed: April 18, 2001
    Date of Patent: November 12, 2002
    Assignee: Denso Corporation
    Inventors: Yoshiki Koyama, Nobumesa Ueda, Hiroshi Fujimoto
  • Patent number: 6467196
    Abstract: The present invention provides a spike, which includes a base (2), a claw (4) formed on a tip end of the base (2) and having a trapezoidal tip end portion, and a recess (6) formed in a rear side of the base (2) and extending from the claw (4) to the base (2), the recess (6) being curved relative to a longitudinal direction (7) of the spike (1).
    Type: Grant
    Filed: February 5, 2001
    Date of Patent: October 22, 2002
    Inventor: Yoshiki Koyama
  • Publication number: 20010032990
    Abstract: A semiconductor device for a load drive circuit includes a main LDMOS device and a sense LDMOS device that are connected to each other in parallel to form a current mirror circuit. The main LDMOS device and the sense LDMOS device have plural drain cells and plural source cells that are arranged to form a generally square shape as a whole. In the plural drain cells, drain cells of the sense LDMOS device are arranged along a diagonal of the generally square shape.
    Type: Application
    Filed: April 18, 2001
    Publication date: October 25, 2001
    Inventors: Yoshiki Koyama, Nobumesa Ueda, Hiroshi Fujimoto
  • Patent number: 6184663
    Abstract: An apparatus for driving an electric load includes a switch device interposed in a current feed path from a direct-current power source to the electric load. A sensing resistor connected in series with the switch device operates for detecting a load current as a voltage value. The load current flows into the electric load via the switch device. A signal generation device operates for generating a trapezoidal wave signal in response to externally applied commands to turn on and turn off the electric load. The trapezoidal wave signal gradually varies from a first predetermined voltage to a second predetermined voltage when the electric load starts to be turned on. The trapezoidal wave signal gradually varies from the second predetermined voltage to the first predetermined voltage when the electric load starts to be turned off.
    Type: Grant
    Filed: August 27, 1999
    Date of Patent: February 6, 2001
    Assignee: Denso Corporation
    Inventors: Hiroshi Imai, Yoshiki Koyama, Shunji Mase