Driver circuit of light sources of the LED type, comprising a first and at least a second group of light sources, each connected to a common power supply terminal (V DD), a first and at least a second regulation circuit, each adapted to regulate the current absorbed by a respective group of light sources, wherein each regulation circuit comprises a driver transistor (T3, T3") connected between the respective group of light sources and the earth and adapted to drive a driving current proportional to a reference electric magnitude (IREF), characterised in that it further comprises at least one actuation circuit operatively connected to a respective second regulation circuit, and serial connection circuit means having a first terminal connected between the first group of light sources and the respective driver transistor and a second terminal connected between the power supply terminal and the second group of light sources, said serial connection circuit means being adapted to connect in series at least a first and a second group of light sources, when the voltage on said first terminal is greater than or equal to the voltage on said second terminal, wherein the actuation circuit comprises a second actuation transistor connected between the power supply terminal and the second terminal and polarisation resistors (R3, R4) operatively connected to the driving transistor (T3") of the second regulation circuit, wherein the regulation circuit of a first group of light sources, the actuation circuit and the regulation circuit of a second group of light sources are configured in such a way that: - when the voltage on the first terminal is less than the voltage on the second terminal, the first group of light sources is driven by the respective regulation circuit, while the driver transistor (T3") of the second regulation circuit is saturated by the polarisation resistors (R3, R4) of the actuation circuit and the actuation transistor drives the second group of light sources, on the basis of a reference electric magnitude (IREF) of said second regulation circuit, in such a way that the first and the second group of light sources are driven in parallel; - when the voltage on the first terminal is greater than the voltage on the second terminal, the first and the second group of light sources connected in series with each other are driven by the second regulation circuit, the driver transistor of the first regulation circuit and the second actuation transistor being switched off. - when the voltage on the first terminal is less than the voltage on the second terminal, the first group of light sources is driven by the respective regulation circuit, while the driver transistor (T3") of the second regulation circuit is saturated by the polarisation resistors (R3, R4) of the actuation circuit and the actuation transistor drives the second group of light sources, on the basis of a reference electric magnitude (IREF) of said second regulation circuit, in such a way that the first and the second group of light sources are driven in parallel; - when the voltage on the first terminal is greater than the voltage on the second terminal, the first and the second group of light sources connected in series with each other are driven by the second regulation circuit, the driver transistor of the first regulation circuit and the second actuation transistor being switched off.