Isolated gate driver for SiC MOSFETs with constant negative off voltage

In recent years, more and more SiC power semiconductor switches have become available, showing their superior behavior for power electronics. To fully exploit the potential of the SiC MOSFET, conventional gate drivers for silicon devices must be adapted to this device due to its special requirements. An isolated gate driver for SiC MOSFETs with constant negative off voltage is presented in this paper. Firstly, the isolation and the floating ground driving are provided by a coupled transformer. Then a negative turn-off voltage is realized by a voltage clamp circuit made up of resistors, capacitors and diode. Moreover, a controllable voltage is introduced to compensate the variable duty ratio and constant off voltage is achieved. As a result, the spurious turn-on phenomena of SiC MOSFETs can be avoided. As isolation, floating ground and constant negative voltage with variable duty ratio are obtained, the proposed gate driver can be widespread utilized in lots of topologies.