A predictive analog dead-time control circuit for a buck converter

In this paper, a one-step predictive dead-time control circuit for a synchronous buck converter is proposed. It consists of dead-time detection and optimization circuits. The detection circuit utilizes an integrated dead-time detection diode which accurately detects body diode conduction of the synchronous MOSFET. The dead-time optimization circuit is an analog circuit which eliminates the major shortcoming of digital methods, specifically dead-time dithering in the steady state. Operation of the circuit is verified using PSIM. The results of the simulation show that the circuit reduces the body diode conduction time of the synchronous MOSFET to less than 4ns at 20A load, 12V input, 1.2V output and 500kHz switching frequency. As a result, the buck converter conduction losses can be reduced by 16.3%.