Abstract: An embodiment of a self-supply circuit, for a voltage converter that converts an input voltage into an output voltage and has a main switch and a controller, designed to control switching of the main switch for controlling the output voltage; the self-supply circuit is provided with: a charge accumulator, which is connected to the controller and supplies a self-supply voltage to the same controller; a generator, which supplies a charge current to the charge accumulator; and an auxiliary switch, which has a first conduction terminal in common with a respective conduction terminal of the main switch and is operable so as to control transfer of the charge current to the charge accumulator. In particular, the self-supply circuit is provided with a precharge stage, connected to the auxiliary switch, which carries out a precharging of an intrinsic capacitance of the auxiliary switch before a turning-off transient of the main switch ends.