Integrated Over-Current and Temperature Monitoring in SiC MOSFETs Using Single-Pad Dual-Mode Sensing

Abstract

The detection of over-currents and short-circuit currents, as well as monitoring the silicon carbide (SiC) MOSFET device temperatures during run-time, is a crucial requirement for reliable power electronics. Currently, integrating device-level sensor features increases the complexity of the manufacturing process and adds to the interface and signal pin count of power modules, compromising power density. This paper presents a novel monolithic SiC MOSFET structure that combines a current mirror with a temperature-dependent resistive element on a single shared pad. A cell concept, including gate control and monitoring circuitry for this innovative dual-mode sensing feature, is introduced and validated in 1200 V prototype power module consisting of 6 to 8 parallel SiC MOSFET dies, representative of typical automotive traction inverter applications in the 200 to 500 kW power class. Experimental results from shortcircuit type 1 and 2 testing, as well as temperature monitoring during inverter tests, are discussed. By enabling both rapid shortcircuit detection and robust junction temperature monitoring, the proposed solution provides a path to safely utilizing low Rds,on devices in automotive systems, enhancing protection without sacrificing performance.