Abstract: A CPU determines if an expansion unit is docked or if there is external power supplied, in accordance with an SMI signal received. When a personal computer is docked to an expansion unit or when supply of external power is initiated, a process for switching the display mode to a high performance display mode for carrying out image display with the optimal display performance available from a display controller is started. When the personal computer is undocked from the expansion unit or when supply of external power is inhibited, a process for switching the display mode to a low power display mode set in the display controller is started. In those mode switching processes, power supply to a VRAM, the setting of a work area and a clock rate are changed.

Abstract: When the display rate of a plasma display reaches a display rate exceeding the rated maximum electric power of the plasma display, the display mode of the plasma display is switched from a high brightness display mode to a normal brightness display mode. An item for selecting whether or not a battery recharge operation is enabled is provided to a setup menu screen. A user arbitrarily selects a charge mode (a battery charge operation is enabled in the normal brightness display mode) or a non-charge mode (the battery charge operation is disabled in the high brightness display mode). When the charge mode is selected, an electric power value obtained by subtracting electric power necessary for recharging the battery from the rated maximum electric power of the plasma display is set as a reference value, and when the display rate requires electric power exceeding the reference value, the display mode is switched from the high brightness display mode to the normal brightness display mode.

Abstract: A power supply control system for a portable computer having a central processing unit (CPU), and operable in response to power supplied from a rechargeable battery or an alternating current (AC) adapter. The control system includes a charge unit for charging the rechargeable battery; current detectors for detecting power status; and a power control microprocessor for controlling the charge unit independently of the CPU in response to a detected power status.

Abstract: When a computer is not externally powered, it operates from installed first and second batteries. In top surface of the computer, LEDs are provided which indicates three states of each battery; need of charging, during charging, and completion of charging.

Abstract: A portable computer that includes a first ROM for storing an OS, a second ROM for storing at least one piece of existing application software, and a flat display panel for displaying at least one icon to read out the existing application software stored in the second ROM. Since the DOS and the application program are respectively stored in a DOS ROM and an application ROM, the DOS or the application can be quickly executed without install processing from floppy disks.

Abstract: When the MS-DOS is not installed from an FDD or an HDD but is installed from a built-in DOS ROM arranged in a memory space in which bank access to the computer main body can be performed, at the time the system power is turned on, a menu display processing program stored in the DOS ROM is executed by the DOS. Upon execution of the program, the arrangement of menu icons can be arbitrarily changed on the menu screen.

Abstract: A personal computer of this invention has a battery pack mounting section for detachably receiving battery packs having different current capacities. The personal computer also includes a switch mechanism for detecting whether a battery pack has a high or low capacity. Battery characteristic values consisting of charge and discharge voltage/current characteristics in units of batteries are prestored in a memory in a power control CPU (PC-CPU). The PC-CPU refers to the memory on the basis of capacity data from the switch mechanism and reads out the corresponding battery characteristic data. A power supply circuit performs optimal charge control on the basis of this characteristic data. Two battery packs are prepared. When the PC-CPU detects that the currently used battery pack is in a low-battery state, it selects the other battery pack to supply the operating power to the personal computer. At the same time the PC-CPU performs optimal charge control of the battery in the low-battery state.

Abstract: A power supply control system for a portable computer having a central processing unit (CPU), and operable in response to power supplied from a rechargeable battery or an alternating current (AC) adapter. The control system includes a charge unit for charging the rechargeable battery; current detectors for detecting power status; and a power control microprocessor for controlling the charge unit independently of the CPU in response to a detected power status.