An electronic device having electronic circuitry powered by a battery and having an interface for interactively coupling the electronic device to a host device, for switching the power source by which power is supplied to the electronic circuitry, and by determining (410) an interface status as being coupled to or detached from the host device. In response to determining (410) that the interface is coupled to the host device, the electronic circuit is coupled (415) to the interface such that power is supplied to the electronic circuitry from the host device. In response to determining (410) that the interface is detached from the host device, the electronic circuit is coupled (420) to the battery.