A device for measuring the current flowing through a power transistor of a voltage regulator, the voltage regulator having an input voltage and providing a regulated output voltage and the power transistor coupled between the input and output voltages. The measuring device includes a further transistor adapted to mirror a portion of the current flowing through the power transistor, the further transistor and the power transistor have a first non-drivable terminal in common that is coupled to the input voltage. The measuring device also includes a circuit block to connect the second non-drivable terminals of the power and the further transistor and to provide an output current equal to the portion of the current flowing through the first transistor; the measuring device further including a circuit adapted to detect the output current of said circuit block.