Patents by Inventor Thomas P. Loftus

Thomas P. Loftus 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).

  • Current sharing control with limited output voltage range for paralleled power converters
    Patent number: 5036452
    Abstract: Current sharing between paralleled power converters is attained by adjusting the error signal in the converters regulation circuit to assure that all the paralleled converters have a regulated output voltage that forces the converters to share the load equally. In particular circuitry is provided to limit the variation in output voltage that can be achieved through operation of the current sharing control.
    Type: Grant
    Filed: December 28, 1989
    Date of Patent: July 30, 1991
    Assignee: AT&T Bell Laboratories
    Inventor: Thomas P. Loftus
  • Circuit for reducing transistor stress and resetting the transformer core of a power converter
    Patent number: 4760512
    Abstract: A single ended forward converter includes a snubber/reset circuit that diverts current flow from the power switching transistor during the turn off transition to significantly reduce switching loss therein. This same circuit is further operative to resonate energy stored in the magnetizing inductance of the power transformer with a capacitor during a nonconducting period of the power switching transistor in order to reverse the polarity of current, in the magnetizing inductor and reset the core, and further obtain bipolar flux excursions in the transformer core during each cycle of operation.
    Type: Grant
    Filed: June 11, 1986
    Date of Patent: July 26, 1988
    Assignee: American Telephone and Telegraph Company, AT&T Bell Laboratories
    Inventor: Thomas P. Loftus