Patents by Inventor Pak TANG

Pak TANG 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).

  • Publication number: 20080030148
    Abstract: In order to achieving wide dimming range for compact and tubular fluorescent lamps, two novel control approaches are proposed. (i) Novel techniques for suppressing oscillatory effects in the Triac circuit so as to maintain stable Triac operation over a wide firing angle range and (ii) a hybrid dimming control technique in the ballast inverter circuit for achieving wide dimming range from 100% to about 3%. Concerning point (i) both dissipative and non-dissipative energy absorption schemes (EAS) are proposed to suppress the transient effects in the Triac circuit when the Triac is turned on. The essence of the EAS is to ensure that the Triac circuit can be operated in a stable manner without oscillations or inadvertent turn-off. With respect to pint (ii) a hybrid dimming method is proposed in which unlike traditional control methods that use inverter frequency control only for dimming purposes, both dc link voltage and inverter frequency are varied.
    Type: Application
    Filed: June 27, 2007
    Publication date: February 7, 2008
    Applicant: E. Energy Technology Limited
    Inventors: Pak TANG, Yiu Lam, Shu Chung, Ron Hui