Digital dimming control of CCFL drive system using pulse density modulation technique

In this paper, a digital dimming controller for the CCFL drive system is presented. The proposed digital controller utilizes pulse density modulation (PDM) technique to adjust the output power. In order to verify the correctness of the proposed method, a FPGA (Field Programmable Gate Array)-based CCFL drive system is also built and tested. The overall system power efficiency is approximately 85%. Comparing to low frequency dimming (LFD) methods, the proposed system can reduce the voltage spike by over 15 %.