| 摘要 |
PROBLEM TO BE SOLVED: To provide a charging circuit for selecting an external power supply with a margin for a supply current and an external power supply with a limited supply current, always charging in the minimum time at the maximum charging current if the power supply with the margin for the supply current is selected and charges, and preventing the external power supply from being damaged without a complicated control for a system circuit if the external power supply with the limited supply current is selected and charges. SOLUTION: The charging circuit includes a connector for connecting at least the first and second external power supplies, first and second reverse current preventing means for preventing a reverse current to the first external power supply, a third reverse current preventing means for preventing a reverse current to the second external power supply, a charge controlling means for controlling from a current from the first or second external power supply and outputting it to a secondary battery, a power supply detecting means for the existence of the first external power supply, and a fourth reverse current preventing means for connecting or disconnecting between the secondary battery and the system circuit in accordance with an instruction from the power supply detecting means. COPYRIGHT: (C)2005,JPO&NCIPI
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