LED backlight driving circuits and dimming method

Oh Kyong Kwon, Young Ho Jung, Yong Hak Lee, Hyun Suk Cho, Ki Soo Nam, Hai Jung In

Research output: Contribution to journalArticle

2 Scopus citations

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.

Original languageEnglish
Pages (from-to)173-181
Number of pages9
JournalJournal of Information Display
Volume11
Issue number4
DOIs
StatePublished - 2010 Jan 1

Keywords

  • Backlight
  • Boost converter
  • Current regulator
  • Dimming algorithm
  • LED

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    Kwon, O. K., Jung, Y. H., Lee, Y. H., Cho, H. S., Nam, K. S., & In, H. J. (2010). LED backlight driving circuits and dimming method. Journal of Information Display, 11(4), 173-181. https://doi.org/10.1080/15980316.2010.9665848