An Integrated Magnetically Isolated Gate Driver Architecture for SiC MOSFET Applications

Applications of SiC MOSFETs as wide-bandwidth devices contains transient processes in which high-speed voltage and current fluctuations during the switching. Accordingly, the implementation of stable isolation architecture is required to ensure electrical security on the primary and stable power driving on the secondary in gate driver circuits. However, the isolation pathways are usually inconsistent, resulting in separate mechanisms for signal and power which adds to the design complexity. An integrated pulse-transformer-based gate driver is proposed in this paper, which uses only one magnetic isolation mechanism to achieve both signal and power isolation. The edge signals are converted into characteristic pulses for injection into a very high frequency isolated power supply, and a simplified signal feature extraction circuit is implemented in the secondary. The solution provides reliable simultaneous transmission with signal propagation delays on the order of the duty cycle time of the power supply. Experimental prototype is constructed on a printed circuit board with a coreless transformer to realize the low isolation capacitance, high isolation voltage, lightweight and low-cost. The proposed integrated dual-isolated gate driver (DIGD) is expected to realize the compact design of distributed isolation for SiC MOSFET applications.