A method and device for generating a power supply voltage (Vf), referenced to a first reference potential (4), in an electronic system including an energizing source (3) connected to the first and second reference potentials (4, 5) so as to impart an AC voltage differential between the reference potentials (4, 5), wherein the device includes: (i) a source (10) for supplying AC voltage, which is referenced to the second reference potential (5), connected to the first reference potential (4), and encompasses the energizing source (3); and (ii) rectifying and filtering elements (1) connected, at the input thereof, to the first reference potential (4) and to the source (10) for supplying AC voltage, respectively, so as to generate, at an output (8), a power supply voltage (Vf) referenced to the first reference potential (4) by rectifying a voltage at the terminals of the source (10) for supplying AC voltage.