A transformer-less cold cathode fluorescent lamp driver

Abstract

A transformer-less cold cathode fluorescent lamp driver for liquid crystal display backlight is proposed in this paper. Commonly, a CCFL driver has a transformer with high turn ratio in order to step up low input voltage to high sinusoidal lamp voltage. This high voltage and high turn ratio transformer has large size and high cost. The proposed transformer-less CCFL driver which is based on parallel-loaded resonant topology features simplicity, so it reduces the complexity and the cost of overall system. And the proposed circuit with the asymmetric control has good dimming capability by duty control. In this paper, the analysis of the proposed CCFL driving circuit and experimental results for 32-inch commercial LCD television backlight are presented.