Switching between source power supply and battery of a system based upon connection status of source power supply and battery and a system parameter indicative of the status of the system

摘要

An electric supply system and device therefor including an AC adapter for supplying electric power received from external thereto; a battery being charged with electric power supplied from this AC adapter and enabled to supply electric power to the system by discharging the charged electric power; and a controller for controlling the supply of the electric power to the system from the AC adapter and the battery. The controller stops the supply of the electric power to the system from the AC adapter so as to supply the electric power to the system from the battery while the AC adapter connected to the system is powered off or loaded lightly.