Patents by Inventor Yuji TAKEYAMA

Yuji TAKEYAMA 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).

  • Overvoltage protection circuit for protecting overvoltage corresponding to wide range of input voltage
    Patent number: 10284075
    Abstract: An overvoltage protection circuit is provided which is connected between a rectifier circuit and a load including an input capacitor element connected to both ends of the load. The overvoltage protection circuit includes a semiconductor switch connected between the rectifier circuit and the load, and a control circuit controls the semiconductor switch. When the rectified voltage exceeds a predetermined value, the control circuit turns off the semiconductor switch, and detects a voltage potential difference between both ends of the semiconductor switch, and then, for an interval when the voltage potential difference is zero or a predetermined minute value, the control circuit generates a control voltage for turning on the semiconductor switch, and outputs the control voltage to a control terminal of the semiconductor switch. The overvoltage protection circuit includes a current change circuit that gradually changes a current flowing through the semiconductor switch.
    Type: Grant
    Filed: August 1, 2018
    Date of Patent: May 7, 2019
    Assignees: RICOH ELECTRONIC DEVICES CO., LTD., NATIONAL UNIVERSITY CORPORATION OITA UNIVERSITY
    Inventors: Shohtaroh Sohma, Yuji Takeyama, Kimihiro Nishijima
  • OVERVOLTAGE PROTECTION CIRCUIT FOR PROTECTING OVERVOLTAGE CORRESPONDING TO WIDE RANGE OF INPUT VOLTAGE
    Publication number: 20190058323
    Abstract: An overvoltage protection circuit is provided which is connected between a rectifier circuit and a load including an input capacitor element connected to both ends of the load. The overvoltage protection circuit includes a semiconductor switch connected between the rectifier circuit and the load, and a control circuit controls the semiconductor switch. When the rectified voltage exceeds a predetermined value, the control circuit turns off the semiconductor switch, and detects a voltage potential difference between both ends of the semiconductor switch, and then, for an interval when the voltage potential difference is zero or a predetermined minute value, the control circuit generates a control voltage for turning on the semiconductor switch, and outputs the control voltage to a control terminal of the semiconductor switch. The overvoltage protection circuit includes a current change circuit that gradually changes a current flowing through the semiconductor switch.
    Type: Application
    Filed: August 1, 2018
    Publication date: February 21, 2019
    Applicants: RICOH ELECTRONIC DEVICES CO., LTD., NATIONAL UNIVERSITY CORPORATION OITA UNIVERSITY
    Inventors: Shohtaroh SOHMA, Yuji TAKEYAMA, Kimihiro NISHIJIMA