A motor vehicle lighting system includes a light source, a multi-phase interleaved power converter having a plurality of selectively activatable elementary converters, each of which is configured to generate an electrical signal having its own phase. The power converter is designed to supply electrical power to the light source, and controller is designed to selectively control each of the elementary converters of the power converter. The controller is designed to receive an emission command for the emission of a desired light beam by the light source and to activate a strictly necessary number of elementary converters of the power converter such that the power converter supplies, to the light source, an electrical power needed to emit the desired light beam.