A novel fast-switching current-pulse driver for LED backlight applications

Abstract

In this work, a novel fast-switching current-pulse driver for dimming controllers of light-emitting diode (LED) backlight applications is proposed. A pair of current switches, which is used to drive the LED string, employs an adaptive bias circuit for low-power dissipation. A negative feedback mechanism and a specific-design discharge current-sink transistor are used to drive the large-size current switches to achieve fast current switching. The proposed current-pulse driver was fabricated in TSMC 0.25-μm 1P4M BCD high-voltage process. The measured rising time and falling time of the LED current are 600 ns and 15 ns, respectively, when the load is a 10-LED string.