Patents by Inventor Keiji Yagi

Keiji Yagi 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: 5140175
    Abstract: A light-emitting diode drive circuit of the present invention comprises: a current supply circuit (3) including a first transistor (16), the base of which receives a first drive pulse signal (S3) output from a signal input circuit, and a second transistor (15), the collector of which is connected to a light-emitting diode (2), the emitter of which is connected to a current source (24) together with the emitter of the first transistor (16), and the base of which receives a second drive pulse signal (S2) having a phase opposite to that of the first drive pulse signal (S3); a fall time shortening circuit (6) including a third transistor (13) which is connected in parallel with the light-emitting diode (2) and the base of which receives an input for short-circuiting both terminals of the light-emitting diode (2) during a turn-OFF time; and a rise time shortening circuit (5) including a circuit (4) for generating a peaking current during a turn-ON time of the light-emitting diode (2), and a fourth transistor (14)
    Type: Grant
    Filed: May 3, 1991
    Date of Patent: August 18, 1992
    Assignee: Mitsubishi Rayon Co., Ltd.
    Inventors: Keiji Yagi, Kazuhiro Zenba, Yukihiro Sekiguchi, Fumio Ishikawa, Tetsuo Yamamoto, Takayuki Aoki