Patents by Inventor Shuuji Shibuya

Shuuji Shibuya 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).

  • Crystal-oscillator circuit
    Patent number: 8228131
    Abstract: In a crystal-oscillator circuit having a quartz crystal unit, further stabilization of output frequency change at a time of startup of the power supply is achieved. A crystal-oscillator circuit having a quartz crystal unit includes a first variable-capacitance element, which forms an oscillation loop with the quartz crystal unit, and a temperature compensation circuit which provides a first control signal for the first variable-capacitance element to compensate for a temperature characteristic of the quartz crystal unit. In addition, the crystal-oscillator circuit includes a second variable-capacitance element group, and a time constant circuit which provides a time constant signal, which changes with a predetermined time constant, for the second variable-capacitance element group as a second control signal.
    Type: Grant
    Filed: January 12, 2011
    Date of Patent: July 24, 2012
    Assignee: Panasonic Corporation
    Inventors: Kei Nagatomo, Hisato Takeuchi, Shuuji Shibuya
  • CRYSTAL-OSCILLATOR CIRCUIT
    Publication number: 20110227655
    Abstract: In a crystal-oscillator circuit having a quartz crystal unit, further stabilization of output frequency change at a time of startup of the power supply is achieved. A crystal-oscillator circuit having a quartz crystal unit includes a first variable-capacitance element, which forms an oscillation loop with the quartz crystal unit, and a temperature compensation circuit which provides a first control signal for the first variable-capacitance element to compensate for a temperature characteristic of the quartz crystal unit. In addition, the crystal-oscillator circuit includes a second variable-capacitance element group, and a time constant circuit which provides a time constant signal, which changes with a predetermined time constant, for the second variable-capacitance element group as a second control signal.
    Type: Application
    Filed: January 12, 2011
    Publication date: September 22, 2011
    Inventors: Kei NAGATOMO, Hisato Takeuchi, Shuuji Shibuya