Patent ID: 7119458

Claim:
A method for charging and maintaining the operation of a battery-powered electronic application device, including the steps of: (A) providing a controllable switching device; (B) providing a plurality of power sources each coupled to said application device via said controllable switching device, said plurality of power sources including at least two of the following; (i) an AC power source; (ii) a DC power source; (iii) a direct oxidation fuel cell; and (iv) a rechargeable battery; and (C) switching said controllable switching device to select between said plurality of power sources to provide operating power to said application device or to charge said rechargeable battery; (D) selecting as a primary power source, said AC power source and determining whether said AC power source is available; (E) if said AC power source is available, selecting said AC power source to power said application device; and (F) if said AC power source is not available, determining whether said DC power source is available and if so, selecting said DC power source to power said application device; (G) if said DC power source is not available, determining whether said rechargeable battery is sufficiently charged to power said application device and if so, selecting said rechargeable battery to power said application device; and (H) if said rechargeable battery is not sufficiently charged, responsively signaling said direct oxidation fuel cell to begin generating electricity to provide current to power said application device.