PORTABLE COMPUTER AND CONTROLLING METHOD THEREOF

摘要

PURPOSE: A portable computer and a controlling method thereof are provided to reduce power consumption due to an LCD(Liquid Crystal Display) device by reducing a vertical frequency supplied to the LCD device when the portable computer is operated by battery power. CONSTITUTION: A power supply(20) supplies power by the power of an AC adaptor(21) or a battery(23). A BIOS(Basic Input Output System) ROM(10) stores a BIOS program for performing a POST(Power On Self Test) process to initialize each device of a system board when a power switch(1) is turned on, and setting the vertical frequency supplied to the LCD device(7) from a video chip(5). The LCD device processes/displays a vertical/horizontal frequency and an RGB video signal supplied from the video chip. A microcomputer(3) detects whether the power is supplied from the AC adaptor or the battery, and provides detection information to the BIOS program. The BIOS program comprises a system BIOS(13) and a video BIOS(15). In case of the AC adaptor, the video BIOS makes the vertical frequency smaller than the case of the adaptor.