A new active gate driver for MOSFET to suppress turn-off spike and oscillation

Abstract

MOSFETs are widely used in power electronics converters. Due to the high di/dt and dv/dt of the MOSFET and parasitic parameters in the circuit, drain voltage spikes and oscillations will be generated during turn-off, which can affect the safety of the device and degrade the system's electromagnetic compatibility. This paper first studies the relationship between drain voltage spike and gate voltage during turn-off. Based on the effect of gate voltage on drain voltage spike, a new active gate driver that optimizes gate voltage is proposed. The proposed active gate driver detects the slope of the drain voltage and generates a positive pulse in the drain current fall phase to increase the gate voltage, thereby suppressing drain voltage spike and oscillation. In order to verify the effectiveness of the proposed active gate driver, a simulation circuit and an experimental platform are constructed and compared with the conventional gate driver. Simulation and experimental results show that the new active gate driver can effectively suppress the drain voltage spike and oscillation of MOSFETs, and can effectively reduce high-frequency EMI.