The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 04, 2007
Filed:
Sep. 06, 2001
Pak Chuen Tang, Kowloon, HK;
Yiu Hung Lam, Kowloon, HK;
Shu Hung Chung, Kowloon, HK;
Ron Shu-yuen Hui, Kowloon, HK;
Pak Chuen Tang, Kowloon, HK;
Yiu Hung Lam, Kowloon, HK;
Shu Hung Chung, Kowloon, HK;
Ron Shu-yuen Hui, Kowloon, HK;
E. Energy Technology Limited, Kowloon, HK;
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. The essence of the new dimming control is to reduce the range of the inverter frequency variation so that the overall dimming range can be made as wide as possible.