Multi-bootstrap driver circuit

摘要

Plural bootstrap capacitors are coupled to an output stage of a MOSFET driver. A conventional bootstrap driver is preceded by one or more additional bootstrap stages. Each one includes a capacitor, a tri state inverter and a delay section. When the output stage is off all capacitors are discharged. To turn the output stage on, all capacitors, including the output gate capacitance, are charged in parallel. Then each capacitor in turn is caused to pump its charge into the gate of the output stage, with the last capacitor pumping the output stage gate voltage to a level well in excess of the applied power supply voltage.