Symmetric Current-Balancing Circuit for LED Backlight With Dimming

Author

Choi, Sungjin ; Kim, TaeHoon

Author_Institution

Sch. of Electr. Eng., Univ. of Ulsan, Ulsan, South Korea

Volume

59

Issue

4

fYear

2012

fDate

4/1/2012 12:00:00 AM

Firstpage

1698

Lastpage

1707

Abstract

One of the key challenges in driving multiple light-emitting-diode (LED) strings for a liquid-crystal-display (LCD) backlight system is to ensure uniform current control. Unequal current sharing between the strings is due to manufacturing spread and temperature variations. In this paper, a novel current-balancing circuit for LED backlights is proposed. A smart combination of an inherent symmetry of circuit and capacitive balancing mechanism enables an efficient and cost-effective current balancing. The operating principle of the proposed method is analyzed, and an appealing generalization is made. The feasibility of the proposed scheme is verified by developing a hardware prototype with a dimming feature to drive a 100-W edge-type backlight system, having six LED strings for a large-scale LCD panel.

Keywords

electric current control; light emitting diodes; liquid crystal displays; LED backlight; dimming feature; large-scale LCD panel; liquid-crystal-display backlight system; multiple light-emitting-diode strings; power 100 W; symmetric current-balancing circuit; temperature variations; uniform current control; Artificial neural networks; Capacitors; Driver circuits; Impedance; Light emitting diodes; Rectifiers; Resistance; Backlight; current balancing; light-emitting-diode (LED) driver; liquid crystal display (LCD);

fLanguage

English

Journal_Title

Industrial Electronics, IEEE Transactions on

Publisher

ieee

ISSN

0278-0046

Type

jour

DOI

10.1109/TIE.2011.2138112

Filename

5742754