Patent ID: 7956576

Claim:
A rechargeable battery pack configured to power an electronic device having a first battery, the rechargeable battery pack comprising: a second battery; an external power input port configured to couple to an external power source; a power output port for powering the electronic device; and a first circuit comprising: a first power path between the external power input port and the power output port of the rechargeable battery pack; a second power path between the second battery and the power output port of the rechargeable battery pack; and a power switch set; wherein: the first circuit is internal to the rechargeable battery pack; the rechargeable battery pack, along with its second battery, external power input port, power output port, and first circuit, is external to and distinct from the electronic device; the second battery of the rechargeable battery pack is supplemental to the first battery of the electronic device; if the external power source is not coupled to the external power input port of the rechargeable battery pack: the first power path is disabled by the power switch set; and the second power path is enabled by the power switch set; and if the external power source is coupled to the external power input port of the rechargeable battery pack: the first power path is enabled by the power switch set; and the second power path is disabled by the power switch set.