LED backlight power system with auto-tuning regulation voltage for LCD panels

This paper proposes a light emitting diode (LED) backlight power system for liquid crystal display (LCD) panels. The proposed power system is regulated by error quantities of feedback circuit from which variation value of the voltage across LED driving IC in each driving LED channel is attained due to changes of temperature on LEDs. With this compensation algorithm, the proposed LED backlight power supply can regulate its output voltage with auto-tuning to compensate a forward drop voltage of multi-LED-string and to maintain a constant voltage across each driving IC when temperature on LEDs is changed Compared with the conventional LED backlight power system, the proposed power system can reduce the temperature on LEDs about 6degC~8degC under driving IC operated in a safety of area. As a result, the proposed power system can reduce the temperature on LED driving IC to increase life cycle of components and reduce color shift significantly. Hardware measurement obtained from experimental prototype has been verified its feasibility.