Layout Considerations for a New Current Sensing Circuit for Online Lifetime Prediction of SiC MOSFETs

Abstract:
This paper describes a new current-sense circuit using shunt resistors and the caveats for its layout. We proposed a current sensing circuit that can observe the current flowing through a switching device such as a SiC MOSFET in the entire operating range, including transient switching operation, using a shunt resistor. Furthermore, we proposed a layout in which the magnetic flux change generated by the current change flowing through the shunt resistor does not affect the current sense circuit. This proposal makes it possible to observe the loss at switching transient while the equipment is in operation and thus allowing an indirect lifetime prediction of the power device.