Design and development of digital control multi-lamp back-light modules for TFT-LCD TV

This paper presents a digital control multi-lamp back-light module for TFT-LCD TV. The driving system consists of three modules and each module adopts three-phase inverters operated with interleaving fashion to drive cold cathode fluorescent lamps (CCFL), which can reduce input current ripple. A three-phase transformer is introduced to prevent current imbalance among lamps in each module. To improve power system dynamic responses during dimming function, phase-shift low frequency pulse-width-modulation (PWM) control signals are adopted to control the power delivered to each module. A digital control three-phase 18-lamp prototype has been built. Experimental results have verified the feasibility of the proposed system.