Digital Lamp Balance System With Individual Lamp Current Control Capability for an LCD TV

Author

Cho, Je-Hyung ; Park, Sang-Hyun ; Seong, Hyun-Wook ; Kim, Hyoung-Suk ; Park, Jin-Sik ; Choi, Eun-Seok ; Youn, Myung-Joong

Author_Institution

Dept. of Electr. Eng., Korea Adv. Inst. of Sci. & Technol., Daejeon, South Korea

Volume

27

Issue

2

fYear

2012

Firstpage

637

Lastpage

641

Abstract

A digital lamp balance system that equalizes lamp current of liquid crystal display (LCD) backlight is implemented in this letter. The proposed digital balance circuit consists of a balance switch which is in series with the lamp and a dc-blocking capacitor which also acts as a ballast capacitor for parallel lighting. The parasitic capacitance of the balance switch is used as parallel impedance which makes the lamp current decrease. Microcontroller unit controls each lamp current by changing the pulsewidth modulation duty ratio of a balance switch. The specified circuit, analysis, balance principles, and experimental results of the proposed system will be presented for a 46-in LCD TV.

Keywords

capacitors; lamps; lighting; liquid crystal displays; microcontrollers; television displays; DC-blocking capacitor; LCD TV; balance switch; ballast capacitor; digital balance circuit; digital lamp balance system; individual lamp current control capability; liquid crystal display backlight; microcontroller unit control; parallel impedance; parallel lighting; parasitic capacitance; pulse width modulation duty ratio; Capacitors; Electronic ballasts; Impedance; Inverters; Switches; Switching circuits; Backlight unit; cold cathode fluorescent lamp (CCFL); electric ballast; lamp current balance; liquid crystal display (LCD) TV;

fLanguage

English

Journal_Title

Power Electronics, IEEE Transactions on

Publisher

ieee

ISSN

0885-8993

Type

jour

DOI

10.1109/TPEL.2011.2172819

Filename

6054060