Patents by Inventor Tatsuya Sawa

Tatsuya Sawa 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).

  • System and method for providing a sample and hold circuit for maintaining an output voltage of a constant current source circuit when a feedback loop is disconnected
    Patent number: 7595622
    Abstract: A system and method are disclosed for maintaining an output voltage of a constant current source circuit. A constant current source circuit is provided that comprises a voltage regulator, a first feedback loop and a second feedback loop that are connected to the voltage regulator, and a sample and hold circuit that is connected to the second feedback loop. The voltage regulator regulates an output voltage VOUT to a reference voltage VREF using a first feedback voltage signal FB on the first feedback loop. The sample and hold circuit samples and holds a second feedback voltage signal VFB from the second feedback loop while the first feedback loop is connected. The voltage regulator regulates an output voltage VOUT to the second feedback reference voltage signal VFB when the first feedback loop is disconnected.
    Type: Grant
    Filed: April 5, 2007
    Date of Patent: September 29, 2009
    Assignee: National Semiconductor Corporation
    Inventors: Kenji Tomiyoshi, Tatsuya Sawa