Digital-dimming controller with current spikes elimination technique for LCD backlight electronic ballast

A novel simple control method to improve the ignition behavior of cold cathode fluorescent lamp in digital-dimming mode is proposed in this paper. To extend the lamp life, we realize a digital-dimming controller with current spikes elimination technique (DDC-CSET) to reduce the high ignition voltage and to eliminate the ignition current spike. The half-bridge resonant inverter is employed in the presented backlight system to promote the system efficiency. Complete analysis and design considerations are discussed in detail in this paper. Experimental results are close to the theoretical prediction. The overall efficiency of the system achieved at the rated power is over 91%. The ignition voltage is reduced about 30% without any lamp current spike occurred under digital-dimming operation.