Disclosed is a charging coil assembly for a mobile device able to wirelessly provide power to charge a battery in an Implantable Medical Device (IMD). The assembly includes a coaxial connector that can be inserted into a coaxial audio port on the mobile device to allow bi-directional communications between the assembly and the mobile device. One or more housings coupled to the connector by a cable can include control circuitry, a charging coil, and a battery. The charging coil can be driven by control circuitry in the assembly or by a charging audio signal at an audio frequency provided by the mobile device via the audio port and connector. A Charging Application on the mobile device can detect and authenticate the charging coil assembly, and render a charging graphical user interface on the mobile device to control and/or monitor charging of the IMD.
