Patent ID: 7394298

Claim:
A driver circuit, comprising: a plurality of switching elements to sequentially switch to charge a gate capacitance of a power switch of a DC/DC converter from a first voltage to a second voltage in a plurality of steps; and a plurality of supply rails coupled to the plurality of switching elements respectively to provide a plurality of voltages including the first voltage, the second voltage, and at least one intermediate voltage between the first and second voltages, wherein the gate capacitance of the power switch is charged from the first voltage to the at least one intermediate voltage via a respective switching element before being charged to the second voltage, wherein at least one intermediate supply rail that provides the at least one intermediate voltage is coupled to the first supply rail via a capacitor in series between the at least one intermediate supply rail and the first supply rail, and wherein the capacitor is to store energy when the gate capacitance of the power switch is discharged from the second voltage to the at least one intermediate voltage or from the at least one intermediate voltage to the first voltage, and wherein the stored energy is used to charge the gate capacitance from the first voltage to the at least one intermediate voltage or from the at least one intermediate voltage to the second voltage in a subsequent switching cycle of the DC/DC converter without drawing power from a power supply.