| 摘要 |
PURPOSE: To realize power conservation by reading out information for deciding the type of power supply and feeding power to all loads when power is fed from an AC adapter but interrupting power supply to specific loads when power is fed from a battery. CONSTITUTION: When an AC adapter 1 is not used, an AC adapter jack 3 is switched to the contact (a) side and one pole of a battery 2 is grounded to close the power supply circuit thereof. Consequently, the input port C of a CPU 5 goes high and the impedance at the output port A thereof is decreased to feed a base current to a transistor Q1 whereas the impedance at the output port B thereof is increased to block base current supply to a transistor Q2. Since the transistor Q1 is turned ON and the transistor Q2 is turned OFF, power is fed only to the load 6a side and the circuit thereof is operated as rated. |
