Circuit arrangement for switching a current and method of operating a semiconductor power switch

Circuit arrangement for switching a current (Ic) in dependence of a predetermined switching signal, comprising: - a semiconductor power switch (44) for switching the current (Ic) and - to generate a control voltage with a time course of a driving means (42, 78, 96, 106) which is adapted to receive the switching signal and in response to the received switching signal to a control input (50) of the semiconductor power switch (44) is through what cause is not abruptly and permanently switched between a conductive and a blocking state of the semiconductor power switch (44), but instead during a switching operation at least one predetermined operating parameter (Uce, max, dIoff / dt, dUoff / dt, dione / dt, DUON / dt) of the semiconductor power switch (44) meets a predetermined criterion, wherein the criterion (by a shift parameter Uce, max, dIoff / dt, dUoff / dt, dion / dt, DUON / dt) of the driving means ( 42, 78, 96, 106) is predetermined and a parameter value of the shift parameter (Uce, max, dIoff / dt, dUoff / dt, dion / dt, DUON / dt) during operation of the circuit arrangement is changed, characterized in that at least one of the following operating variables by setting a parameter value, a criterion can be predefined: - a sloping over a transistor and / or diode of the semiconductor power switch (44) voltage (Uce, max), - a slope (dUoff / dt, DUON / dt) of a time course of this voltage, - a slope (dIoff / dt, dion / dt) of a time course of the current to be switched (Ic), and can be predetermined by the parameter value as a criterion, a limit value or a desired value for the operating variable (Uce, max, dIoff / dt, dUoff / dt, dion / dt, DUON / dt), and - a measuring device (64, 66, 80, 82, 98, 100) for detecting the following operating variables (Ic, T, Ud) by which an operation state of the semiconductor power switch (44) is described, there is provided: - a temperature (T) of a transistor (46) of the semiconductor power switch (44) and / or a temperature of a to the transistor (46) anti-parallel connected diode (48) of the semiconductor power switch (44), wherein in the case capturing at least one of the temperatures of the parameter value for the falling voltage (VCEmax) dependent on the sensed operative quantity, and / or - both a current strength of a through the semiconductor power switch (44) flowing current (Ic) and one above the semiconductor power switch sloping (44) voltage (Ud), in which case the slope of the current and / or the slope of the voltage dependent on the sensed operative quantity.