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:
Jun. 24, 2014
Filed:
Apr. 02, 2012
Ching-ho Chou, Taoyuan Hsien, TW;
Yung-chuan LU, Taoyuan Hsien, TW;
Ching-Ho Chou, Taoyuan Hsien, TW;
Yung-Chuan Lu, Taoyuan Hsien, TW;
Delta Electronics, Inc., Taoyuan Hsien, TW;
Abstract
A current-preheat electronic ballast includes an AC-to-DC converter, a controlling unit, an auxiliary voltage generator, and an inverter. The inverter is connected with the DC bus for converting a high DC voltage into an AC output voltage and generating a resonant current and a lamp filament current to a lamp group. The inverter includes a resonant circuit and a resonant capacitor adjusting circuit. The resonant circuit provides electric energy required to preheat the lamp group. The resonant capacitor adjusting circuit judges whether the inverter is enabled according to the detecting element. After the inverter has been enabled for a delayed time, two high-voltage switching terminals of the resonant capacitor adjusting circuit are correspondingly conducted or shut off, so that an equivalent resonant capacitance value of the resonant circuit is changed and a voltage drop across two ends of a lamp filament of the lamp group is changed.