Power supply apparatus for portable computer and DC input selection circuit adapted to the same

摘要

Disclosed is a power supply apparatus which permits a docking station to be operated with a battery power from a battery pack of a portable computer even if supply of AC power to the docking station is accidentally cut off. The apparatus for a portable computer system for use with a docking station having a logic circuit for expanding functions of the portable computer comprises a DC input selection circuit placed on the portable computer side, for switching between the first and second DC voltages to provide a switched DC voltage to the portable computer as well as the docking station, so that the docking station is operated with the second DC power source even though supply of AC power to the docking station is cut off.