INFORMATION PROCESSING EQUIPMENT

摘要

PURPOSE:To display a screen with low luminance at drive of a battery state and with high luminance at drive of an external power supply respectively by detecting the supply of the drive power received from an external power supply and then switching the drive current of a display device based on the detecting result of the power supply detection means. CONSTITUTION:An AC adaptor 2 is selected and a pin 7 of the AC adaptor 2 is connected to a jack 8 attached to an information processing equipment 1. Thus the output of the adaptor 2 which is set at a level higher than the voltage of a battery 3 is supplied to the equipment 1 via an output switch circuit 9 as the drive power (a). At the same time, a supply detection circuit 10 detects the connection of the adaptor 2 with the output of this adaptor 2. Then a luminance control signal (b) is outputted from the circuit 10 and inputted to a drive circuit 13. Thus an FL tube 12 is driven with high luminance at drive of the adaptor 2 requiring no preference to be given to the low power consumption. Meanwhile the tube 12 is driven with low luminance at drive of the battery 3 so that the low power consumption is maintained.