Patents by Inventor Kazuyoshi Asakawa

Kazuyoshi Asakawa 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: 8120338
    Abstract: A dropper-type regulator capable of providing a soft start function using a simple circuit configuration. An exemplary regulator includes a first FET having a relatively high current driving capability and a second FET having a relatively low current driving capability are provided in parallel between an input terminal and an output terminal. For a predetermined time immediately after power activation, only the second FET is driven, thereby preventing a large rush current. A switch circuit connected to the gate of the first FET is operated after the predetermined period of time, thereby supplying a driving voltage to the gate of the first FET.
    Type: Grant
    Filed: December 3, 2008
    Date of Patent: February 21, 2012
    Assignee: Oki Semiconductor Co., Ltd.
    Inventors: Norihiro Kawagishi, Kazuyoshi Asakawa
  • Patent number: 8058854
    Abstract: A drive circuit includes a plurality of output drive terminals and a plurality of push-pull circuit stages. Each of the push-pull circuit stages includes a pair of complementary transistors having a common terminal connected to a respective output drive terminal. The drive circuit further includes a plurality of first transistors connected in series with at least one of the pair of complementary transistors of the push-pull circuit stages, respectively, and a common second transistor. The common second transistor is connected with each of the plurality of first transistors to form a current mirror circuit. The drive circuit further includes a mirror current setting circuit for setting a mirror current flowing through the common transistor.
    Type: Grant
    Filed: December 24, 2008
    Date of Patent: November 15, 2011
    Assignee: Oki Semiconductor Co., Ltd.
    Inventors: Norihiro Kawagishi, Kazuyoshi Asakawa
  • Publication number: 20100237818
    Abstract: A driving circuit feeds driving current to a coil in a brushless motor, and feeds bias current to a Hall element that senses the rotational position of the motor. The driving current and bias current are supplied from the same power supply, but the bias current passes through a load element that reduces power dissipation by the Hall bias circuit by causing some of the power to be dissipated by the load element instead. The Hall bias circuit can therefore be combined with the other driving circuitry into a single integrated circuit, even if the brushless motor is driven at a comparatively high voltage.
    Type: Application
    Filed: March 11, 2010
    Publication date: September 23, 2010
    Applicant: OKI SEMICONDUCTOR CO., LTD.
    Inventors: Yuichi Ohkubo, Hiroyuki Kikuta, Norihiro Kawagishi, Kazuyoshi Asakawa
  • Publication number: 20100237926
    Abstract: A voltage generating circuit including first and second voltage sources, and a subtracting circuit. The subtraction circuit is configured as a differential amplifier including an op-amp and four resistors, with an inverting input terminal of the op-amp connected to the second voltage source via a first resistor, a second resistor connected between the inverting input terminal and an output terminal of the op-amp, a non-inverting input terminal of the op-amp connected to the first voltage source via a third resistor of the same size as the second resistor, the non-inverting input terminal of the op-amp connected to a reference potential terminal via a fourth resistor of the same size as the first resistor, the first voltage from the first voltage source and the second voltage from the second voltage source inputted to the subtracting circuit, and the subtracting circuit outputting a third voltage having a positive temperature coefficient.
    Type: Application
    Filed: March 16, 2010
    Publication date: September 23, 2010
    Applicant: OKI SEMICONDUCTOR CO., LTD.
    Inventors: Hiroyuki Kikuta, Yuichi Ohkubo, Kazuyoshi Asakawa
  • Patent number: 7741884
    Abstract: A load drive circuit which can operate at high speed with low consumption current while performing the gate-to-source over voltage protection for its load driving field-effect transistor. A Zener function device is connected between the gate and the source of the load driving field-effect transistor, and an on/off-switch circuit to supply either on-potential or off-potential to the gate of the field effect transistor is provided. The current flowing through the Zener function device when the load driving field-effect transistor is conductive is limited by the on/off-switch circuit.
    Type: Grant
    Filed: December 3, 2008
    Date of Patent: June 22, 2010
    Assignee: Oki Semiconductor Co., Ltd.
    Inventors: Norihiro Kawagishi, Kazuyoshi Asakawa
  • Publication number: 20090184603
    Abstract: A drive circuit includes a plurality of output drive terminals and a plurality of push-pull circuit stages. Each of the push-pull circuit stages includes a pair of complementary transistors having a common terminal connected to a respective output drive terminal. The drive circuit further includes a plurality of first transistors connected in series with at least one of the pair of complementary transistors of the push-pull circuit stages, respectively, and a common second transistor. The common second transistor is connected with each of the plurality of first transistors to form a current mirror circuit.
    Type: Application
    Filed: December 24, 2008
    Publication date: July 23, 2009
    Applicant: OKI SEMICONDUCTOR CO., LTD.
    Inventors: Norihiro Kawagishi, Kazuyoshi ASAKAWA
  • Publication number: 20090153122
    Abstract: A dropper-type regulator capable of providing a soft start function using a simple circuit configuration. An exemplary regulator includes a first FET having a relatively high current driving capability and a second FET having a relatively low current driving capability are provided in parallel between an input terminal and an output terminal. For a predetermined time immediately after power activation, only the second FET is driven, thereby preventing a large rush current. A switch circuit connected to the gate of the first FET is operated after the predetermined period of time, thereby supplying a driving voltage to the gate of the first FET.
    Type: Application
    Filed: December 3, 2008
    Publication date: June 18, 2009
    Inventors: Norihiro KAWAGISHI, Kazuyoshi Asakawa
  • Publication number: 20090153200
    Abstract: A load drive circuit which can operate at high speed with low consumption current while performing the gate-to-source over voltage protection for its load driving field-effect transistor. A Zener function device is connected between the gate and the source of the load driving field-effect transistor, and an on/off-switch circuit to supply either on-potential or off-potential to the gate of the field effect transistor is provided. The current flowing through the Zener function device when the load driving field-effect transistor is conductive is limited by the on/off-switch circuit.
    Type: Application
    Filed: December 3, 2008
    Publication date: June 18, 2009
    Applicant: OKI SEMICONDUCTOR CO., LTD.
    Inventors: Norihiro KAWAGISHI, Kazuyoshi ASAKAWA