Abstract: A zero voltage switching power conversion circuit for driving a CCFL has a ZVS circuit and a full bridge circuit composing of MOS transistors. A transformer is coupled between the full bridge circuit and the CCFL. By properly controlling the conducting timing of each MOS transistor, power is coupled from the primary side to the secondary side of the transformer thus supplying power to the CCFL. When adjusting the brightness of the CCFL, the high frequency signal is able to be temporarily shut down during off periods of the CCFL to reduce power consumption.