Multistring LED Backlight Driving System for LCD Panels With Color Sequential Display and Area Control

In this paper, a multistring light-emitting diode (LED) backlight driving system for liquid crystal display (LCD) panels with color sequential display (CSD) and area control is proposed. In large-scale LCD panels, multistring LED backlights are required to provide sufficient back lighting. The most popular structure to achieve multistring current regulation is a current mirror. However, it cannot be applied to high-power LED (>100 mA) driving, and the number of LEDs in each string is highly limited. In the driving system, a multioutput flyback converter associated with a novel control IC is proposed to tightly regulate LED driving currents and to readily achieve CSD and area control. The proposed driving system for a 32-in LCD panel has been built, from which experimental measurements have verified that the proposed driving system has the following features: low power consumption, high power conversion efficiency, stable driving currents, and high reliability.