Triangular and Rectangular Power Pulses in Automotive MOSFETs Applications for Thermally Unstable Linear Mode

This paper explores the conversion of triangular power pulses into rectangular ones, a technique widely employed for thermally stable linear mode operation. With this research, we extend the application of this same technique to the electro-thermally unstable linear mode operation of silicon low-voltage power MOSFETs, with less than 100V drain-to-source voltage (V
DS
) rating. Experimental evidence is provided showing that, during electro-thermal instability, the MOSFET current limit for a constant voltage and a triangular current pulse is two times that of a rectangular pulse. This has been proved to be valid across the board by collecting data on MOSFETs with different packages, die sizes, blocking voltages, gate voltage levels and trench technologies. Furthermore, verification by means of analytical models is provided to demonstrate the validity and advantages of this approach, which allows for no additional testing and accelerated time to market. In automotive, the ability to address this kind of behavior is necessary in case of capacitive pre-charge and active clamp, where a variable voltage and or current lead to triangular dissipated power over time.