Patent ID: 6917234

Claim:
A power switch arrangement comprising: a semiconductor power switch having a control electrode terminal, a load-side electrode terminal, a load path and a maximum desired temperature, wherein the semiconductor power switch is connected by its load path serially in a load circuit; a clamping circuit connected between the control electrode terminal and the load-side electrode terminal of the semiconductor power switch, wherein turn-off of the semiconductor power switch occurs at a turn-off instant and sets a clamping voltage across the load path; a temperature estimator that supplies an estimated temperature value corresponding to an instantaneous peak temperature of the semiconductor power switch that occurs directly after the turn-off instant of the semiconductor power switch; and a control device that generates, after the turn-off instant, a control signal that is fed to the clamping circuit if the estimated temperature value exceeds the maximum desired temperature of said semiconductor power switch, wherein the control device controls the clamping circuit in such a way that the clamping circuit sets the clamping voltage such that the instantaneous peak temperature does not exceed the maximum desired temperature, wherein a minimum voltage value of the clamping voltage is not exceeded, and wherein the minimum voltage value is determined in such a way that a change in load current through the semiconductor power switch with respect to time does not become positive and is subsequently increased, first gradually and then very rapidly.