A Low-Cost High-Performance Voltage Sensing Circuit With Proactive Parameter Design Compensation Network for SiC MOSFETs

Abstract

Wide bandgap semiconductors show superior material properties enabling silicon carbide (SiC) metal-oxide-semiconductor field-effect transistors (MOSFETs) present good features on its switching speed and withstand voltage. However, the high voltage and fast switching characteristics of SiC MOSFETs also put forward new requirements for voltage measurement, that is, high bandwidth under high voltage conditions. This article proposes a new voltage divider structure and a proactive parameter design compensation network to build high voltage and high bandwidth voltage sensing circuit. This structure utilizes the characteristics that the same resistor has the same parasitic capacitance to meet the high frequency constraints of the voltage sensing circuit. The influence of parasitic parameters and load parameters on circuit performance is analyzed in detail, which provides a basis for the compensation network design. By combining the proposed voltage sensing circuit with an appropriate proactive parameter design load effect compensation network (PDCN), the withstand voltage rating of the low-voltage and high-bandwidth voltage probes can be extended to required levels. Different from other existing methods, PDCN can actively design the compensation circuit parameters and provide the optimal parameters of the compensation circuit. This lead to a smaller input capacitance than the state of the art commercial voltage probes, which will help to obtain better performance when measuring high-speed switching voltage. The performance of the voltage measurement is experimentally verified and compared by SiC-based double pulse test (DPT) circuits.