Saturated pulse transformer based power MOSFET gate drive

This thesis described on investigates a circuit proposed by International Rectifier. The proposed circuit depends on the saturated operation of pulse transformer. It is well known that pulse-transformer base-drive offers excellent isolation. However, pulse transformer also needs bipolar primary drive voltage and a DC source at its secondary. This makes pulse-transformer base drive circuit expensive to realized. A RC pulse shaping circuit in series with the saturable transformer will transform a unipolar rectangular input pulse into two narrow pulses. The pulse energy is transferred to the secondary, i.e., to the base capacitance of the transistor via the source-drain diode of a charge-controlled MOSFET. The voltage of the base capacitance is maintained until the arrival of the negative going pulse. The negative going pulse effectively turns on the charge-controlled FET and drains the base capacitance rapidly.