A Bidirectional Communicating Power Supply Circuit for Smart Gate Driver Boards

Abstract

In power circuits, the gate drivers are required to provide an optimal and safe switching of power semiconductor devices. Nowadays, the gate driver boards include more and more features, such as short-circuit detection, soft-shutdown, temperature sensing, on-state voltage monitoring. Research works are in progress on the integration of on-line monitoring features for a predictive maintenance. The instrumentation of the gate drive system supposes the integration of a communication system to transmit the monitoring data. In high-power designs, a galvanic isolation is mandatory on the gate driver board. The parasitic capacitance seen on the isolation barrier is critical in these designs as it can lead to the circulation of common mode currents during the switching. Adding extra optocouplers or transformers on the isolation barrier is, therefore, risky due to electromagnetic interference constraints. In this article, a new bidirectional data transmission method is proposed for gate drivers used for driving 1.2 kV silicon carbide (SiC) power metal oxide semiconductor field effect transistors (mosfets). The proposed method enables the energy transmission and a bidirectional data exchange on a single power supply transformer. The experimental results are provided demonstrating 1 Mb/s for TxD and 16 kb/s for RxD. The targeted application is the health monitoring of SiC power mosfets using the gate driver board.