Efficienct LED driver with an adaptive reference tracking technique

An adaptive reference tracking driving technique is proposed to minimize the boost output voltage oscillation and improve the power efficiency when the digital pulse width modulation dimming is enabled. An asynchronous 1 MHz DC/DC converter with a dynamic resistor implements the minimum voltage reference tracking technique. Therefore, high efficiency and a stable boost output voltage can be guaranteed whether the LED strings turn on or off. The test chip was simulated by TSMC 0.25 um BCD 40 V to demonstrate high efficiency and the stable boost output voltage. Simulation results show the oscillation output voltage can be minimized from 1.4 V to 0.2 V.