Patent ID: 6429550
Filing Date: 2002-08-06
Classification: H02H

Abstract:
A polarity reversal protective circuit for an electronic output stage drivable by a drive circuit, power FETs being used in at least one supply terminal to interrupt a connection of a wrongly applied supply voltage, comprising:a n-channel power FET having a source terminal, a gate terminal and drain terminal, the N-channel power FET being looped with a source-drain path of the N-channel power FET into a positive supply terminal of a supply voltage, the source terminal being coupled to the positive supply terminal; and a NPN transistor having a collector, a base, and an emitter, the collector being coupled to the gate terminal of the N-channel power FET, the collector being further coupled via a current-limiting resistor to an output of a drive circuit, the emitter being coupled via a diode to the positive supply terminal of the supply voltage, the diode being conductive when the supply voltage is incorrectly applied, the base being coupled via a base resistor to a negative supply terminal of the supply voltage.