REVERSE POLARITY PROTECTION CIRCUIT FOR A MOTOR VEHICLE ELECTRICAL NETWORK, AND MOTOR VEHICLE ELECTRICAL NETWORK HAVING A REVERSE POLARITY PROTECTION CIRCUIT

摘要

The invention relates to a reverse polarity protection circuit (9) for a motor vehicle electrical network (1), fed from an energy source (2) having a higher voltage than the nominal voltage (12V) of the motor vehicle electrical network (1) by means of a first DC/DC transformer (DCDC1), comprising a first connection (11) for the positive potential of the nominal voltage (12V) of the motor vehicle electrical network (1), a second connection (12) for the ground potential of the motor vehicle electrical network (1), and a third connection (13) for an auxiliary potential. Said circuit further comprises a switch (Tr3; ReIl; Tr4), the first terminal thereof being connected to the first connection (11) and the second terminal thereof being connected to the third connection (13). The reverse polarity protection circuit (9) is formed by an actuating circuit (10) for actuating the control connection of the switch (Tr3, ReIl, Tr4), connected to the three connections (11, 12, 13) for the supply thereof, and implemented such that the control connection for switching on the switch (Tr3; ReIl, Tr4) is actuated only if the potential at the third connection is greater than a reference potential.