PROTECTION CIRCUIT FOR A POWER SUPPLY UNIT, AND POWER SUPPLY UNIT WITH A RESPECTIVE PROTECTION CIRCUIT

摘要

The protection circuit serves for the monitoring of output voltages of a power supply unit which has a normal mode and a standby mode. The protection circuit comprises a first switching stage (T 1 ), coupled to the current input ( 1 ) of which are output voltages (U 5 -U 8 ) which are present both in the normal mode and in the standby mode and coupled to the control input of which are output voltages (U 1 -U 3 ) which are only present in the normal mode. A control signal (Us), by which the power supply unit is switched over between normal mode and standby mode, is coupled to the control input ( 2 ) of this switching stage (T 1 ). As a result, by means of the control signal, the output voltages which are only present in the normal mode are blocked in the standby mode by the control signal, so that in the standby mode only the output voltages (U 5 -U 8 ) which are coupled to the current input ( 1 ) are monitored.