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 (EMI) constraints. In this paper, a new bidirectional data transmission method is proposed for gate drivers used for driving 1.2kV SiC power MOSFETs. The proposed method enables the energy transmission and a bidirectional data exchange on a single power supply transformer. Experimental results are provided demonstrating 1Mb/s for TxD and 16kb/s for RxD. The targeted application is the health monitoring of SiC power MOSFETs using the gate driver board.

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