Electronic ballast with piezoelectric transformer for cold cathode fluorescent lamps

Author

Moo, C.S. ; Chen, W.M. ; Hsieh, H.K.

Author_Institution

Dept. of Electr. Eng., Nat. Sun Yat-Sen Univ., Kaohsiung, Taiwan

Volume

150

Issue

3

fYear

2003

fDate

5/1/2003 12:00:00 AM

Firstpage

278

Lastpage

282

Abstract

To miniaturise the ballast circuit, a half-bridge series-resonant inverter with a cascading Rosen-type piezoelectric transformer (PT) is designed for cold cathode fluorescent lamps (CCFLs). The PT is interposed between the resonant circuit and the lamp as a stage of the voltage amplifier to increase the lamp voltage and hence to reduce the sizes of the reactive components. The circuit parameters are designed to operate the inverter at a switching frequency that will have the highest boost ratio of PT, and with zero voltage switching (ZVS) for the active power switches to achieve high circuit efficiency. The lamp power is regulated by duty-ratio control with asymmetrical pulsewidth modulation (APWM). An electronic ballast designed for a 2.2 W CCFL is built and tested to verify the; simulated results.

Keywords

DC-AC power convertors; amplifiers; bridge circuits; cathodes; fluorescent lamps; invertors; lamp accessories; piezoelectric devices; power transformers; resonant power convertors; switching convertors; 2.2 W; ZVS; active power switches; asymmetrical pulsewidth modulation; cascading Rosen-type piezoelectric transformer; circuit efficiency; cold cathode fluorescent lamps; duty-ratio control; electronic ballast; half-bridge series-resonant inverter; resonant circuit; switching frequency; voltage amplifier; zero voltage switching;

fLanguage

English

Journal_Title

Electric Power Applications, IEE Proceedings -

Publisher

iet

ISSN

1350-2352

Type

jour

DOI

10.1049/ip-epa:20030254

Filename

1199689