Patents by Inventor Phillip D. Hardwick

Phillip D. Hardwick 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: 4727874
    Abstract: A pulse width modulation technique regulates the output power of each cycle of a radio frequency surgical signal of an electrosurgical generator. The delivered power of the surgical signal is determined by multiplying the sensed current and the sensed voltage of the surgical signal. An error signal is established by the difference of the actual delivered power with respect to a selected desired output power. The error signal is operatively utilized to modulate the pulse width of each driving pulse which creates the cycles of the surgical signal. Limits on the sensed voltage and sensed current signals are established to limit the output characteristics of the surgical signal. A minimum current limit signal is utilized to limit the maximum output voltage into relatively high impedances. A minimum voltage limit signal is utilized to limit the maximum output current into relatively low impedances.
    Type: Grant
    Filed: September 10, 1984
    Date of Patent: March 1, 1988
    Assignee: C. R. Bard, Inc.
    Inventors: William J. Bowers, Phillip D. Hardwick