A charging bench includes three coils that partially overlap, in superposed planes. An electrical feed makes it possible to supply the coils with an AC current from the mains. A portable device to be charged is placed on the upper side of this charging bench. This device includes a winding intended to receive the electrical charging, and a ferrite protective screen. One of the coils (Bb) is selected to emit the magnetic charging flux toward the mobile phone. The selection is carried out via the emission of a series of pulses by at least one of the coils and comparison of return signals with a reference threshold. This comparison also enables one of the other coils (Ba, Bc) to be selected or both of these other two coils (Ba, Bc) to be used to receive a flux for communicating information originating from the portable device to be charged.