A circuit for driving a LED assembly comprising an LED illumination device. The circuit includes a switch, an inductor, in a series connection with the switch, the switch, in its closed state, charges the inductor and in its open state, allows the inductor to discharge. The circuit includes a current measurement element to measure a current flowing through the inductor and/or the LED illumination device in the open and closed state of the switch, and a comparator to compare a signal representing the current measured by the current measurement element with a reference. The switch, inductor and current measurement element establish, in operation, a series connection with the LED illumination device. An output of the comparator is provided to a driving input of the switch for driving the switch between its open and closed state upon a change of an output state of the output of the comparator.