Skyworks Solutions, Inc.
GENERATION OF POSITIVE AND NEGATIVE SWITCH GATE CONTROL VOLTAGES

Abstract:

A technique for powering gate drivers in a half-bridge configuration uses a single external power supply to power each gate driver. A single on-chip regulator regulates the positive turn-on voltage for each switch. The regulator overhead, is also used as the negative voltage for turn-off, thus transferring the low-frequency variation of the external power supply to the negative turn-off voltage. Accordingly, a single on-chip regulator generates both the positive turn-on voltage and the negative turn-off voltage. In at least one embodiment, reuse of the switch turn-off current further reduces on-chip power dissipation. The on-chip regulator's output filter capacitor discharges during turn-on of the external power switching device. During turn-off, the current that discharges the switch gate capacitance recharges the regulator filter capacitor.