Patents by Inventor Masaru Wakatabe

Masaru Wakatabe 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: 6038150
    Abstract: A secondary subcircuit of a converter circuit is disclosed where a method and circuit for operating a transistor to prevent reverse conduction of the current in the secondary subcircuit is disclosed. The diode in the secondary subcircuits of the prior art is replaced by a transistor and the circuitry for controlling the transistor is made part of the control circuit (ASIC). The secondary converter subcircuit includes a secondary coil for generating a voltage that passes through a first transistor M1, a capacitor, and a second transistor M2, where the output terminal of the subcircuit is across said capacitor. A presently preferred embodiment of a control circuit detects the voltage level at a sync node and the output voltage level at the output terminal and controls transistors M1 and M2 accordingly in generating the desired voltage level at the output terminal.
    Type: Grant
    Filed: March 13, 1998
    Date of Patent: March 14, 2000
    Inventors: Hsian-Pei Yee, Satoru Sawahata, Masaru Wakatabe
  • Patent number: 5345100
    Abstract: A semiconductor rectifier having a high breakdown voltage and a high speed operation is provided, which comprises a semiconductor substrate including a first semiconductor layer of one conductivity type and a second semiconductor layer of one conductivity type provided on the first semiconductor layer, a third semiconductor layer of an opposite conductivity type having a depth D and formed in the second semiconductor layer to provide a pn junction therebetween, the third semiconductor layer defining a plurality of exposed regions of the second semiconductor layer, each of the plurality of exposed regions of the second semiconductor layer having a width W, a relation between the depth D and the width W being given by D.gtoreq.0.5W, and a metal electrode provided on the substrate surface.
    Type: Grant
    Filed: September 13, 1993
    Date of Patent: September 6, 1994
    Assignee: Shindengen Electric Manufacturing Co., Ltd.
    Inventors: Takashi Kan, Masaru Wakatabe, Mitsugu Tanaka, Shinji Kunori, Akira Sugiyama
  • Patent number: 5262669
    Abstract: A semiconductor rectifier having a high breakdown voltage and a high speed operation is provided, which includes a semiconductor substrate having an N.sup.+ -type semiconductor layer and an N-type semiconductor layer, a P.sup.+ -type semiconductor layer formed in the N-type semiconductor layer to provide a PN junction therebetween, the P.sup.+ -type semiconductor layer defining exposed regions of the N-type semiconductor layer, and a metal layer provided on an entire surface of the semiconductor substrate having the P.sup.+ -type semiconductor layer to provide contact surfaces of Schottky barrier between the metal layer and each of the exposed regions of the N-type semiconductor layer. In the structure, a configuration of the PN junction is provided to satisfy conditions given by 0.degree.<.theta..ltoreq.135.degree. and 3Wbi.ltoreq.W.ltoreq.2W.sub.B where .theta.
    Type: Grant
    Filed: April 17, 1992
    Date of Patent: November 16, 1993
    Assignee: Shindengen Electric Manufacturing Co., Ltd.
    Inventors: Masaru Wakatabe, Mitsugu Tanaka, Shinji Kunori
  • Patent number: 4997738
    Abstract: An electrophotographic photoreceptor comprises a photoconductive layer having a protective layer disposed thereon, said protective layer being formed by dehydrocondensation of the hydrolyzate of a perfluoroalkyl silane coupling agent, or the hydrolyzate of a mixture of a perfluoroalkyl silane coupling agent and a silane coupling agent. The photoreceptor is very useful in that it can exhibit a high performance even in an environment at a higher temperature and at a higher humidity and that it has a high resistance to the abrasion with a great number of sheets being printed and with the cleaning members and that it is capable of preserving a high resolution without any image blurring.
    Type: Grant
    Filed: November 27, 1989
    Date of Patent: March 5, 1991
    Assignees: Shindengen Electric Manufacturing Co., Ltd., Yamanashi Electronics Co., Ltd., Japan Atomic Energy Research Institute
    Inventors: Minoru Kumakura, Mitsuhiro Yoshitome, Masaru Wakatabe, Masahiro Horigome, Kazuhiko Shima