Analysis of Intrinsic Switching Losses in Superjunction MOSFETs Under Zero Voltage Switching

Abstract

Switching losses of power transistors usually are the most relevant energy losses in high-frequency power converters. Soft-switching techniques allow a reduction of these losses, but even under soft-switching conditions, these losses can be significant, especially at light load and very high switching frequency. In this paper, hysteresis and energy losses are shown during the charge and discharge of the output capacitance (COSS) of commercial high voltage Superjunction MOSFETs. Moreover, a simple methodology to include information about these two phenomena in datasheets using a commercial system is suggested to manufacturers. Simulation models including COSS hysteresis and a figure of merit considering these intrinsic energy losses are also proposed. Simulation and experimental measurements using an LLC resonant converter have been performed to validate the proposed mechanism and the usefulness of the proposed simulation models.

Keywords

• soft-switching
• superjunction mosfet
• llc resonant converter
• zero voltage switching
• c_oss hysteresis
• c_oss intrinsic energy losses