Base drive energy recovery for a silicon bipolar junction transistors

To enable fast switching of a silicon carbide bipolar junction transistor a low impedance base current path is required, traditionally implemented by a RC speed up circuit in parallel to the base resistance. For fast switching speeds the capacitance of this circuit has to be large, dissipating significant power during high frequency switching. This study demonstrates, for the first time, the implementation of an energy recovery (ER) circuit into the base drive; transferring stored energy within the pulse capacitor of the RC circuit back to the power supply. Measured performance of a 1.7 kW boost converter demonstrates an 15.1% reduction in base power losses of the proposed driver when compared with a conventional benchmark operated at a switching frequency of 143 kHz.