Comparison of Two Types of Single Gate Drivers for SiC MOSFET Stacks in Flyback Converters

In some high-voltage low-power applications, silicon carbide metal-oxide-semiconductor field-effect transistor (SiC MOSFET) stack is required to withstand the high voltage. Instead of using separated gate driver for each SiC MOSFET, the single gate driver only requires one standard gate driver to drive all the series connected SiC MOSFET in the stack with the help of some passive components. Despite of its advantage of cost-efficiency, however, it is vulnerable to the voltage oscillation of power loop due to its working principal. Therefore, in this paper, the single gate driver is analyzed in a flyback converter application since an abrupt power loop voltage dropping would occur when it is operating in discontinuous conduction mode (DCM), and two types of single gate drivers are compared. Besides, in order to obtain better switching performance, suitable design guidelines are provided for both two types. Finally, the experimental results verify the correctness of the analysis.