One-step digital dead-time correction for DC-DC converters

Abstract

This paper introduces a novel one-step digital control technique that can dynamically optimize the dead-times for the turn-on and turn-off of the power MOSFETs in DC-DC converters. A NOR gate and a delay-line circuit are used to detect and measure the duration of the unwanted low-side MOSFET body-diode conduction. Based on this measurement, the optimum dead-time is calculated on-the-fly and the DPWM controller will respond immediately to maximize the conversion efficiency in the next switching cycle. This approach is well suited for digital IC implementation. Experimental results from a digitally controlled 6V to 1V, 10A synchronous buck converter verified the efficiency improvement and the practical implementation of the proposed one-step dead-time correction algorithm. This one-step dead-time correction can improve the converter's efficiency by 2 to 4%, depending on output current, output voltage and switching frequency.