Patents by Inventor Kazunori Matsuzawa

Kazunori Matsuzawa 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: 7113412
    Abstract: In charging a gate of a NMOS transistor Q1, the charging speed is adjustable by varying a resistor R1. When an inputted pulse signal VIN reverses to a negative voltage, a diode D2 turns off. Then, current flows along a discharging loop formed by the gate capacitor, the resistor R1, the emitter of the transistor Q2, the base of the transistor Q2, the resistor R2 and the capacitor C1, the transformer T1 and the source of the NMOS transistor Q1. A reverse bias voltage is applied to the gate of the NMOS transistor Q1, thereby keeping the NMOS transistor Q1off-state stably.
    Type: Grant
    Filed: March 29, 2005
    Date of Patent: September 26, 2006
    Assignee: Tamura Corporation
    Inventors: Geliang Shao, Kiyoshi Obikata, Kimio Yoshimi, Kazunori Matsuzawa, Masaru Kubota
  • Publication number: 20050231989
    Abstract: In charging a gate of a NMOS transistor Q1, the charging speed is adjustable by varying a resistor R1. When an inputted pulse signal VIN reverses to a negative voltage, a diode D2 turns off. Then, current flows along a discharging loop formed by the gate capacitor, the resistor R1, the emitter of the transistor Q2, the base of the transistor Q2, the resistor R2 and the capacitor C1, the transformer T1 and the source of the NMOS transistor Q1. A reverse bias voltage is applied to the gate of the NMOS transistor Q1, thereby keeping the NMOS transistor Q1 off-state stably.
    Type: Application
    Filed: March 29, 2005
    Publication date: October 20, 2005
    Inventors: Geliang Shao, Kiyoshi Obikata, Kimio Yoshimi, Kazunori Matsuzawa, Masaru Kubota
  • Publication number: 20050225178
    Abstract: A switching power supply apparatus has a plurality of switching power supply circuits. A control IC (IC1) in a switching power supply circuit generates a PWM drive signal and a synchronizing signal, and also generates DC voltage according to a duty ratio of the PWM drive signal. A control IC (IC2) in the other switching power supply circuit is provided with the synchronizing signal from the IC1 via a transformer, and controls based on a PWM drive signal synchronized with the synchronizing signal. Therefore, switching timing completely matches among the plurality of switching power supply circuits.
    Type: Application
    Filed: March 29, 2005
    Publication date: October 13, 2005
    Inventors: Geliang Shao, Kiyoshi Obikata, Kimio Yoshimi, Kazunori Matsuzawa, Masaru Kubota