Method and driver for power field-effect switches with refreshed power supply providing stable on/off switching

摘要

Drivers for field-controlled switches are powered and switched on and off by the same combined command and power signal which consists of a command signal modulated by a clock signal forming a command envelope including a train of clock pulses. Presently, the first clock pulse in the train is used to restore power to the driver lost through leakage from the driver during the switch signal low state. The invention prevents power from being lost by refreshing power during the PWM low state, such that the command high state pulses need not be used for restoring power. Power and a command to a field-controlled driver is provided by a combined command power signal consisting in the on-state of groups of clock pulses, the groups being a function of a the switch signal pulse width, and in the off-state of the absence of the group of clock pulses. During the off-state of the driver, power is refreshed. In addition, the dead time occurs within the driver circuit, while the driver is being switched on by integrating the clock pulses.