Circuit arrangement for protecting a network from a supply unit to be operated against overvoltages

The invention relates to a circuit arrangement for protecting a to be operated from a power supply unit against overvoltages having an input having first and second input terminal, which communicate with the supply network in connection, and an output A with a first and a second output terminal to which the protected connectable unit, as well as with a protection circuit that is provided between first and second input terminal, to limit the voltage applied to it, wherein the protective circuit comprises a power semiconductor IGBT and a control for the power semiconductor. According to the invention the drive is designed as a driver which detects overvoltage events by means of a logic assembly LB and the power semiconductor IGBT activates the same up to the decay in an overvoltage event and this is used to trigger the power semiconductor IGBT with an increased gate voltage of up to 100 V at a steep switching edge.