Robust and efficient synchronous buck converter with near-optimal dead-time control

Abstract

In switching power converters, the turn on/off process of switches is crucial for the reliability and efficiency of the converter. In general, optimum switching is challenging, and it is particularly difficult for hard switching. The MOSFET synchronous buck converter having wide applications due to high switching speed and low loss, however, operates in hard switching and needs a good timing control for its switching. On/off commutation dead-times should be adjusted care fully in accordance with load current change. Previous work on the dead-time control includes predictive gate drive technique, load current sensing, sensor-less optimization technique, and delay-locked loops. These techniques have problems of sensing noisy switching node or load current, and requiring high quantizing resolution. In this paper, a near optimum dead-time control method is proposed that resolves such problem.