Fast transition current-type burst-mode dimming control for the LED back-light driving system of LCD TV

摘要

In fact, the title does not propagate the content of this paper. It should be changed to “Ripple Free Converter for Driving LED Backlight of LCD TVs.” Due to Improvement on luminous efficacy, long life and wide color gamut, LED has gradually substituted for cold cathode fluorescent lamp as backlight. The proposed driving system adopts sequential color scanning scheme to improve light utilization efficiency by removing color filter To meet display performance requirement that chromaticity variation ⊿uv needs to be limited below 0.002, this paper also proposes a family of output current ripple free topologies to reduce chromaticity variation caused by ripple current. In addition, magnetic amplifiers are introduced to achieve accurate current control among multi-LED strings, and a driving voltage reseter is introduced to eliminate current spikes, improving backlight uniformity, reliability and availability significantly. A forward-type output current ripple free topology with magnetic amplifiers has been built to sequentially drive color LED arrays, from which experimental measurements have verified the discussed performance and feasibility of the proposed system.