Patents by Inventor Khanh T. Le

Khanh T. Le 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).

  • D.C. chopper regulating method and apparatus incorporating bilateral regulating voltage path
    Patent number: 5218522
    Abstract: An unregulated D.C. input voltage (V.sub.IN) is processed by a high power chopper (34,36) to produce a first chopped signal having the same voltage as the input (V.sub.IN), and by a low power chopper (56,58) to produce a second chopped signal in synchronism with and having a lower voltage than the first chopped signal. The first and second chopped signals are algebraically combined by transformers (52,54) to produce an A.C. output signal which may be converted to D.C. (V.sub.OUT). The second chopped signal may be controlled to have the same polarity relative to the first chopped signal in which case the voltages add to increase the output voltage (V.sub.OUT), or to have the opposite polarity relative to the first chopped signal in which case the voltages subtract to decrease the output voltage (V.sub.OUT). The periods of addition and subtraction are alternated within the period of the first chopped signal.
    Type: Grant
    Filed: March 3, 1992
    Date of Patent: June 8, 1993
    Assignee: Hughes Aircraft Company
    Inventors: Thomas K. Phelps, Khanh T. Le, Gilbert I. Cardwell, Jr.