Patents by Inventor Katsuhiko Fukuhara

Katsuhiko Fukuhara 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: 7554173
    Abstract: A semiconductor device accurately monitoring temperature of a semiconductor chip even in a noisy environment, while not requiring a highly accurate detection circuit. A PTC element is bonded onto an IGBT chip. Then, a constant current flows from a constant current source through the PTC element, and an output voltage of the PTC element is detected by a voltage monitor. When output voltage increases, a voltage applied to a gate electrode by a detection circuit is decreased. Since the PTC element is directly arranged on the IGBT chip, the temperature of the IGBT chip can be monitored with high accuracy. Further, since the change in output voltage of the PTC element per 1° C. is large, a highly accurate detection circuit is not necessary, thereby allowing accurate monitoring of the temperature of the IGBT chip even in a noisy environment.
    Type: Grant
    Filed: December 19, 2005
    Date of Patent: June 30, 2009
    Assignee: Mitsubishi Electric Corporation
    Inventors: Takashi Inaguchi, Takeshi Ohi, Katsuhiko Fukuhara, Naoshi Yamada, Yoshitsugu Inaba, Takao Mitsuhashi
  • Publication number: 20080006897
    Abstract: A semiconductor device accurately monitoring temperature of a semiconductor chip even in a noisy environment, while not requiring a highly accurate detection circuit. A PTC element is bonded onto an IGBT chip. Then, a constant current flows from a constant current source through the PTC element, and an output voltage of the PTC element is detected by a voltage monitor. When output voltage increases, a voltage applied to a gate electrode by a detection circuit is decreased. Since the PTC element is directly arranged on the IGBT chip, the temperature of the IGBT chip can be monitored with high accuracy. Further, since the change in output voltage of the PTC element per 1° C. is large, a highly accurate detection circuit is not necessary, thereby allowing accurate monitoring of the temperature of the IGBT chip even in a noisy environment.
    Type: Application
    Filed: December 19, 2005
    Publication date: January 10, 2008
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Takashi Inaguchi, Takeshi Ohi, Katsuhiko Fukuhara, Naoshi Yamada, Yoshitsugu Inaba, Takao Mitsuhashi