Patent ID: 8766672

Claim:
An electronic switching device comprising: a first bipolar junction transistor adapted to control a flow of current between a pair of switching terminals; a second bipolar junction transistor coupled with the first bipolar junction transistor to form a Darlington pair; a charge recovery circuit coupled to a base of the first bipolar junction transistor and adapted to establish a supply voltage across a capacitor by storing in the capacitor charge carriers accumulated in the base of the first bipolar junction transistor during application of a base drive current, a quantity of accumulated charge carriers depending on the base drive current; the charge recovery circuit further including a second diode coupled to conduct accumulated charge carriers from a base of the second bipolar junction transistor when it is switched off to the capacitor; and a controllable current source adapted to control the base drive current, thereby controlling the supply voltage, the controllable current source coupled between the capacitor and the base of the second bipolar junction transistor.