Polarity inversion protection circuit has thermally coupled and matched electronic valve and thermal switch that opens electrical connection and isolates valve from supply if valve heats up

摘要

The circuit has supply connections, an electrical connection for connecting the circuit unit a supply connection, an electronic valve that short circuits if the polarity is reversed and a thermal switch that protects it from damage. The valve and thermal switch are thermally coupled and matched so the thermal switch interrupts the electrical connection and isolates the valve from at least one supply connection if the valve heats up. The circuit has connections (5,6) to the direct voltage supply, an electrical connection (14) for connecting the circuit unit (3) to one of the supply connections, an electronic valve (10) designed and connected between the supply connections so that it short circuits when the polarity is reversed and a thermal switch (12) that protects the valve from damage. The electronic valve and thermal switch are thermally coupled together and matched to each other so that the thermal switch interrupts the electrical connection and separates the valve from at least one connection if the valve heats up. Independent claims are also included for the following: a method of protecting a circuit unit supplied with a direct voltage against damage caused by polarity inversion of the direct voltage supply.