A power management integrated circuit including a reference signal generator, a start-up unit and a supervisory circuit. The supervisory circuit includes an electrical resistance circuit connected between a first end node and a second end node; a power supply input for receiving a supply voltage, this power supply input being connected to the first end node; a low reference potential node; a comparator for comparing a reference voltage value at a first input and a divided voltage value at a second input connected to an internal electrical node of the electrical resistance circuit, the comparator can output a monitoring signal. The supervisory circuit includes a switch controlled by the start-up unit so that the switch is selectively closed and opened based on a detected operational state of the reference signal generator indicating a normal functioning phase of the power management circuit.