Patents by Inventor Feng Chang Hu

Feng Chang Hu 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).

  • Instant start for an electronic ballast preconditioner having an active power factor controller
    Patent number: 5834906
    Abstract: An electronic ballast for driving a fluorescent lamp includes an electromagnetic interference (EMI) filter and power circuit, a preconditioner coupled to the EMI filter and power circuit and an inverter circuit coupled to the preconditioner for energizing the fluorescent lamp. The preconditioner includes an active power factor controller and a boost circuit which is controlled at least in part by the active power factor controller. The active power factor controller has a reference voltage input to which is applied a reference voltage. At start up, the inverter provides a time varying signal which is rectified.
    Type: Grant
    Filed: May 31, 1995
    Date of Patent: November 10, 1998
    Assignee: Philips Electronics North America Corporation
    Inventors: John Chou, Yongping Xia, Feng Chang Hu