LCD panel sector-dimming controlled high efficiency LED backlight drive system

This paper presents an LCD panel sector-dimming controlled high efficiency LED backlight drive system. The proposed LED backlight drive system is composed of a high efficiency DC-DC converter capable of operating over a universal AC input voltage (180~265 V) and a high performance LED backlight sector-dimming controller. The proposed system achieves high efficiency with a soft-switching asymmetrical half-bridge DC-DC converter using a synchronous rectifier and an LED backlight sector dimming controller using lossless power semiconductor switches (MOSFETs). In order to achieve high performance, the proposed system performs the sector -dimming and the current regulation using a low-cost microcontroller and MOSFET switching, resulting in high contrast and brightness. A 90 W laboratory prototype was built and tested. The experimental results verify the feasibility of the proposed system.