Patents by Inventor Nathan R. Kennedy

Nathan R. Kennedy 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).

  • Piezo harn self-oscillating drive circuit
    Patent number: 4496914
    Abstract: A circuit is disclosed for driving a piezo ceramic device as used in smoke alarms or other audio warning devices. The circuit detects the resonant frequency of the piezo horn and provides an alternating current at the resonant frequency of the horn for maximum sound output. The circuit has a self starting resonant oscillation characteristic. Two pairs of switches act in concert to alternatingly connect each side of the piezo horn to the supply voltage and ground, causing the maximum voltage swing across the piezo horn to be effectively twice the available power supply voltage.
    Type: Grant
    Filed: November 13, 1981
    Date of Patent: January 29, 1985
    Assignee: Texas Instruments Incorporated
    Inventors: Bernhard H. Andresen, Stephen R. Schenck, Nathan R. Kennedy