A buck converter for providing a current for an LED includes an input for connection of a DC voltage source; an output for connection of the LED; and a Buck diode, a Buck inductor and a Buck main switch which has a control electrode, a working electrode and a reference electrode. The diode and the main switch are coupled in series, wherein the connecting point between the diode and the main switch is coupled to the second output connection. The converter includes: an auxiliary winding which is coupled to the inductor and has a connection which is coupled to the second input connection and a connection which is coupled to the control electrode of the switch, wherein the auxiliary winding is coupled to the inductor such that, when current is flowing through the switch, a current is provided through the auxiliary winding to the control electrode of the switch.