Abstract: Apparatus for feeding a discharge lamp such as a mercury vapor lamp mounted in series with a choke from a direct current source comprising a chopper of direct current including an electronic switch and a detector of current intensity mounted in series with the choke. A first comparator compares the intensity of the current to a maximum level for opening the switch when the maximum level is reached and a second comparator compares the intensity of the current to a minimum value for closing the switch when the minimum value is reached. The lamp choke and current detector are connected in series with one another and a diode is mounted in parallel therewith and is oriented in the direction to pass current from the negative terminal towards the positive terminal of the direct current source.