Browse > Article

LED Backlight Driving Circuits and Dimming Method  

Kwon, Oh-Kyong (Department of Electronic Engineering, Hanyang University)
Jung, Young-Ho (Department of Electronic Engineering, Hanyang University)
Lee, Yong-Hak (Department of Electronic Engineering, Hanyang University)
Cho, Hyun-Suk (Department of Electronic Engineering, Hanyang University)
Nam, Ki-Soo (Department of Electronic Engineering, Hanyang University)
In, Hai-Jung (Department of Electronic Engineering, Hanyang University)
Publication Information
Journal of Information Display / v.11, no.4, 2010 , pp. 173-181 More about this Journal
Abstract
In this paper, light-emitting-diode (LED) backlight driving circuits and dimming method for medium-sized and large liquid crystal displays (LCDs) are proposed. The double loop control method, the intelligent-phase-shifted PWM dimming method, the fast-switching current regulator, and the current matching techniques are proposed to improve not only the current regulation characteristics and the power efficiency but also the current matching characteristics and the transient response of the LED current. The brightness of the backlight using the proposed local dimming method was determined from the histogram of the local block to reduce the power consumption of the backlight without image distortion. The measured maximum power efficiency of the LED backlight driving circuit for medium-sized LCDs was 90%, and the simulation results showed an 88% maximum power efficiency of the LED backlight driving circuit for large LCDs. The maximum backlight power-saving ratio of the proposed dimming method was 41.7% in the simulation with a high-contrast image. The experiment and simulation results showed that the performance of LEDs as LCD backlight units (BLUs) improved with the proposed circuits and method.
Keywords
LED; backlight; boost converter; current regulator; dimming algorithm;
Citations & Related Records
연도 인용수 순위
  • Reference
1 C. Lai and C. Tsai, IEEE Trans. Consumer Electron. 55, 669 (2008).
2 N. Narendran and Y. Gu, IEEE J. Display Tech. 1, 167 (2005).   DOI   ScienceOn
3 D. A. Steigerwald, J. C. Bhat, D. Collins, R. M. Fletcher, M. O. Holcomb, M. J. Ludowise, P. S. Martin, and S. L. Rudaz, IEEE J. Selected Topics In Quantum Electron. 8, 310 (2002).   DOI   ScienceOn
4 Y. Hu and M. M. Jovanovic, IEEE Tran. Power Electron. 23, 3116 (2008).
5 S.-Y. Tseng, S.-C. Lin and H.-C. Lin, in Proc. IEEE Appl. Power Electron. Conf. (2008), p. 551.
6 M. Doshi and R. Zane, in Proc. IEEE Appl. Power Electron. Conf. (2007), p. 287.
7 S.-I. Hong, J.-W. Han, D.-H. Kim, and O.-K. Kwon, ISSCC 2010 Digest of Technical papers (2010), p. 116.
8 L. Kerofsky and S. Daly, in SID Tech. Dig. (2009), p. 1242.
9 H. Cho and O.-K. Kwon, IEEE Trans. Consumer Electron. 55, 839 (2009).
10 F. Lin, C. Liao, L. Liao, Y. Huang, and H. Shieh, in SID Tech. Dig. (2007), p. 1343.
11 J. Y. Tsao, IEEE Circuits & Devices Mag. 20, 28 (2004).   DOI   ScienceOn