Sequential Color LED Back-Light Driving System for LCD Panels

In this paper, a sequential color light emitting diode (LED) backlight driving system for liquid crystal display (LCD) panels is proposed. 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 where color variation Delta UV needs to be limited below 0.002, this paper also proposes a family of output current ripple free topologies to reduce color variation caused by ripple current. In addition, a driving voltage resetter is introduced to resolve current-spike problem, improving backlight reliability and availability. A forward-type current ripple free converter has been built, from which experimental measurements have verified the discussed performance and feasibility of the proposed system