| 摘要 |
PROBLEM TO BE SOLVED: To provide a backup battery charge circuit for a portable apparatus capable of extending a data hold time in a backup operation. SOLUTION: The backup battery charge boosting circuit 6 is operated after a power circuit 2 is turned off by a power circuit battery-voltage detection circuit 3, voltages are constantly fed to a backup memory 16 and a clock function 17, and a backup secondary battery 18 is charged. When a battery voltage of a main battery 1 comparatively drops, the backup battery charge boosting circuit 6 is turned off, and from the time of the drop, the backup memory 16 and the clock function 17 are driven by the backup operation of the backup secondary battery 18. COPYRIGHT: (C)2004,JPO |
