Advanced Characterization of Low-Voltage Power MOSFETs in Synchronous-Rectifier Buck-Converter Applications

This paper deals with the performance evaluation of low-voltage power MOSFETs as low side switches in synchronous rectifier buck converter applications. The MOSFET technological structure is based on a strip geometry layout, which allows an excellent trade-off between the on-resistance and the gate charge in comparison with other technologies. The paper starts with the description of the main technology issues focusing on the innovations and the advantages. Furthermore, a new high current device with an optimized gate charge profile is introduced. The switching behavior of the tested devices in DC-DC converter applications (voltage regulator modules) has been experimentally analyzed, in detail, placing attention on the on-state power losses of the low-side switch, on the spurious turn-on phenomenon that can occur during the switching transients, on the gate driving conditions, and on the extension of load current range through the use of multiphase converters. The efficiency of the converter has been evaluated in order to put in prominence the significant improvement obtained by using the new generation of high-current, low-voltage MOSFETs.