| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a power switching circuit capable of preventing an overcurrent in conducting switching between an external DC power source and a secondary battery, and achieving safe and stable power supply. <P>SOLUTION: This power circuit conducts switching between the external DC power source 1 and the secondary battery 5 charged by a charging circuit 4. The circuit comprises a switching means 6 for switching power between the external DC power source 1 and the secondary battery 5, a voltage detecting part 12, a switching means 13 for preventing the occurrence of the overcurrent in switching the power supply, and a voltage detector 14. A voltage which is a little lower than the voltage detected by the voltage detecting part 12 and which is at least a minimum input voltage of a load circuit 8, taken as a reference voltage. When the voltage detector 14 detects the reference voltage or lower, the switching means 13 is turned off. When the voltage detecting part 14 detects the voltage which is higher than the reference voltage, the switching means 13 is turned on. <P>COPYRIGHT: (C)2004,JPO |
