Proportional regenerative base driver circuit with negative off-state voltage for SiC bipolar junction transistors

A proportional base driver circuit for SiC bipolar junction transistors is presented. A current transformer feeds a proportion of the transistor's collector current into its base. The influence of the current transformer's magnetising current on its output current is addressed, as are minimum reset time restrictions. The circuit applies a negative off-state baseemitter voltage. Combining this and a regenerative proportional base drive current does not incur undue complexity or cost. The circuit is evaluated in a buck converter supplied from a 600V rail, switching at 50kHz and at a duty factor of 85%, and outputting 2.52kW.