| 摘要 |
PROBLEM TO BE SOLVED: To prevent extension of access time in a memory backup operation. SOLUTION: A clock changeover part is installed in order to shorten the access time of a control system 7 by changing the processing speed of the control system 7, so as to make it correspond to a change in a power-supply voltage VA detected by a detection part 19 used to detect the power-supply voltage VA of the control system in a memory backup operation, When a battery is removed or the like, the processing speed is changed, the extension of the access time is prevented, and the unwilling operation of the control system can be prevented. Generally, changes in the power-supply voltage VA is a drop in the power-supply voltage, and the change in the processing speed is a drop in the processing speed. The power supply of the power-supply voltage VA is a secondary battery 25. |
