The invention provides a device for driving the electrical power supply of at least one electronic circuit branch comprising at least one light source of an automotive vehicle. A converter circuit converts an input voltage VIN into a load voltage (or current) that is applied to said circuit branch, and control means are configured to control the converter circuit by means of a periodic PWM signal having a predetermined frequency f. The frequency f is adapted in real time and according to a disruption that is detected in the input voltage signal VIN in order to avoid any occurrence of flickering in the intensity of the luminous flux emitted by the light sources.