Enhanced di/dt-RC Sensing Structure for Accurate Dynamic Current Measurement in Paralleled SiC MOSFETs

Paralleling SiC mosfets offers a cost-effective way to increase current capability for high-power applications. However, unbalanced dynamic current sharing among paralleled devices can result in uneven losses and thermal distribution, potentially causing device failure. To monitor or actively balance the currents, a current sensor capable of tracking high-di/dt dynamic currents is required. Existing sensing methods, however, often struggle with poor integration and high cost, while the di/dt-RC sensing for paralleled devices remains underexplored. This article presents a comprehensive evaluation of di/dt-RC sensing for paralleled SiC mosfets. To enhance the sensing accuracy and mitigate issues generated by circulating current, a novel $R_{\mathrm{K}}$ sensing structure is proposed in this article. The proposed $R_{\mathrm{K}}$ sensing structure requires only three passive components (2 resistors and 1 capacitor) per mosfet and can be easily scaled for multiple devices, making it highly advantageous for industrial applications. Circuit-level simulations support the analysis, and experimental results validate that the proposed sensing structure can accurately track dynamic currents under various conditions.