A device (10) for charging a mobile terminal by magnetic coupling, includes a first charging module (11) designed to form a charging signal at a first charging frequency, a primary coil (13) composed of a set of turns, a ferromagnetic body (14), a second charging module (12) designed to form a charging signal at a second charging frequency, higher than the first charging frequency. Furthermore, the charging device includes first routing elements (150) designed to connect/disconnect the primary coil (13) to/from the first charging module (11) and to/from the second charging module (12), elements (16) for adjusting the number of turns on the primary coil (13) and elements (19) for saturating the ferromagnetic body (14) at the second charging frequency. A charging method is also described.