| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a power supply system which is high in safety and excellent in availability. <P>SOLUTION: This power system 1 is provided with a VD 6 which detects the connection of an external battery power source 3 by detecting whether the voltage of a terminal 10 is over a first specified level or not, and a resistor R1 and a resistor R2 as external voltage detectors which detect the external power voltage supplied from the external battery power source 3 in a body casing 5 of an electronic apparatus 2. When the external power connection detector detects the external battery power source 3 being connected, a CPU 9 switches an internal circuit 10 from the internal circuit 8 to the external battery power source 3 to connect it, and when the external power voltage detector detects the external power voltage having dropped under a second voltage level, it switches the internal circuit 10 from the external battery power source 3 to the internal battery 8 to connect it. Accordingly, when the external battery power source 3 is connected to the electronic apparatus 2, it can perform contiguous action which can enhance the availability of the power system 1. <P>COPYRIGHT: (C)2004,JPO</p> |
