Abstract: The invention concerns a method for powering a discharge lamp with a switching power supply. Said method is characterised in that it consists in: applying a voltage firing the lamp, then after the lamp has been energized, applying a lower service voltage to the firing voltage. The firing and service voltages can be generated by using a resonant circuit at the terminals of which a chopped voltage is applied with different frequencies. The invention also concerns a light source comprising a discharge lamp and a switching power supply. Said light source can be equipped with devices for measuring several parameters, such as power, light intensity or the amplitude of vibrations. The invention is useful for producing public lighting.