A new low voltage swing gate driver for integrated buck converter with synchronous rectifier

Abstract

This paper presents a new low-swing gate-driver for a buck converter. In the pro posed gate drive technique, the converter output voltage is used to supply gate driver. Also, by controlling gate pulses properly, energy recycling is achieved and efficiency is improved. In addition, zero voltage switching condition is achieved for front-end switches which results in reduced switching power losses. To overcome converter start up problem, a simple circuit which consists of two diode-connected NMOS are used to pre-charge the converter output capacitor. This circuit does not have any effect on the converter output voltage at steady state operation. Since the output voltage is used for supplying the switch driver, th e converter can operate with smaller supply voltages and als o the efficiency is improved. A prototype with switching frequency of 660MHz in O.18/-lm CMOS technology is simulated and simulation results verify the operation principles and design procedure.