Operating circuit for at least one light-emitting diode, - comprising a switching regulator circuit, - which is supplied with a direct current (V in), and - which is designed to provide a supply voltage for the at least one light-emitting diode by means of a coil and a switch timed by a control unit, wherein - the switch is timed by the control unit being designed to alternately turn on the switch for a switch-on duration (t on) between a respective turning on and an immediately following turning off of the switch and for a switch-off duration (t off) between a respective turning off and a following turning on of the switch, and - wherein energy is built up in the coil when the switch is turned on and discharged via the at least one light-emitting diode when the switch is turned off, characterized in that - the operating circuit is designed to add an additional value to a voltage representing a detected switch current (U S), wherein the additional value is the larger, the steeper an increase of the switch current is after turning the switch on again, - wherein the control unit is designed - to compare the voltage (U S) to which the additional value was added to a reference value (U ref) in order to determine the switch-on duration (t on) of the switch, and - to turn off the switch again when the voltage (U S) to which the additional value was added reaches or exceeds the reference value (Uret) (sic). - comprising a switching regulator circuit, - which is supplied with a direct current (V in), and - which is designed to provide a supply voltage for the at least one light-emitting diode by means of a coil and a switch timed by a control unit, wherein - which is supplied with a direct current (V in), and - which is designed to provide a supply voltage for the at least one light-emitting diode by means of a coil and a switch timed by a control unit, wherein - the switch is timed by the control unit being designed to alternately turn on the switch for a switch-on duration (t on) between a respective turning on and an immediately following turning off of the switch and for a switch-off duration (t off) between a respective turning off and a following turning on of the switch, and - wherein energy is built up in the coil when the switch is turned on and discharged via the at least one light-emitting diode when the switch is turned off, characterized in that - the operating circuit is designed to add an additional value to a voltage representing a detected switch current (U S), wherein the additional value is the larger, the steeper an increase of the switch current is after turning the switch on again, - wherein the control unit is designed - to compare the voltage (U S) to which the additional value was added to a reference value (U ref) in order to determine the switch-on duration (t on) of the switch, and - to turn off the switch again when the voltage (U S) to which the additional value was added reaches or exceeds the reference value (Uret) (sic). - to compare the voltage (U S) to which the additional value was added to a reference value (U ref) in order to determine the switch-on duration (t on) of the switch, and - to turn off the switch again when the voltage (U S) to which the additional value was added reaches or exceeds the reference value (Uret) (sic).