A Low-Cost High-Bandwidth Easy-to-Design Current Sensing Circuit for SiC MOSFETs

Abstract

Using current sense resistor (CSR) is an easy and reliable method to sense current. However, when using CSR to sense a transient current even the tiny parasitic inductance of non-inductive CSR brings a significant impact on its sensing performance. In this paper, a low-cost high-bandwidth and easy-design transient current sensor circuit which uses CSR and an LR network to compensate for the effect of parasitic inductance is proposed. The effect of the load on the performance of the proposed current sensing circuit when connecting it on the oscillation is analyzed in detail. Finally, experimental studies under an inductive load double pulse test (DPT) setup with SiC MOSFETs are carried out to verify the validity and feasibility of the proposed transient current sensing circuit. The LR network in the proposed current sensing circuit can fully compensate for the effect of parasitic inductance on CSR.