BACKUP SWITCHING DEVICE FOR PORTABLE COMPUTER

摘要

PURPOSE: A backup switching device for portable computer is provided to make a device simple and to reduce production costs by producing a power stabilization sensing signal and a backup switching signal concurrently through one a voltage detector. CONSTITUTION: A backup switching device for a portable computer includes; a voltage detecting circuit (220 and 230) for detecting a predetermined level potential according to difference after comparing potential of a main battery with reference potential corresponding to the battery being used; and a signal delay circuit (320) for producing a signal whether power can be supplied to a system of the portable computer according to the level potential detected by the voltage detecting circuit (220 and 230) and producing a switching selection signal between the main power and the backup power. The reference potential of the voltage detecting circuit is set differently according to the kind of the battery.