T27.4 - Optimizing MOSFET Selection for EMC-Critical Automotive Applications

This paper investigates the effect of a range of device parameters on the ringing and EMC produced by low voltage silicon Superjunction MOSFETs in a half-bridge configuration. The damping factor is employed as a benchmark to quantify the oscillations of the drain current waveform. Simulated evidence is presented to demonstrate the impact of these parameters on the low side device which is then validated through experimental testing. EMC sweeps were conducted to correlate the damping factor with electromagnetic interference levels, providing a quantitative link between oscillation behavior and EMC performance. This research aims at identifying the optimal design choices to select the device for different automotive applications, including dc-dc, motor drives and isolation or load switches. This is done by observing the impact of internal parameters of the MOSFET, including the die size and its integrated snubber, allowing improvements to be made to the device’s ringing without altering the external circuit. The impact of these parameters is compared to the performance of MOSFETs through a simulated sensitivity analysis and experimental validation.