The present invention concerns an electronic circuit power supply device, configured to: flow, through a first conductor connected to a node, a first current that is an image of a second current consumed by the electronic circuit; flow a third current through a second conductor connected to the node, a first branch of a current mirror conducting the third current; flow a fourth constant current through a third conductor connected to the node; consume a fifth current that is an image of the third current; and regulate a potential of the node by acting on a gate potential of a transistor electrically in series with a second branch of the current mirror.