Circuit providing a control voltage to a switch and including a capacitor

摘要

A circuit for providing a control voltage to a switch includes a capacitor, a first pair of switches for coupling the capacitor to an input voltage source and a second pair of switches for coupling the capacitor to the switch. The first pair of switches is controlled by a control signal in response to the voltage across the capacitor in order to prevent overcharging the capacitor beyond a first predetermined level. The second pair of switches is controlled by a second control signal in response to the voltage across the switch in order to replenish the capacitor voltage when the capacitor voltage falls to a second predetermined level. The first and second pairs of switches are closed during non-overlapping time intervals in order to isolate the switch from the input voltage source, thereby preventing switching transients from affecting the input voltage source and permitting the circuit to be used to drive a variety of switch types arranged in a variety of configurations.