| 摘要 |
PURPOSE:To extend the service life of a backup battery by controlling an oscillation circuit in response to ambient temperature to change a refresh clock frequency. CONSTITUTION:The frequency of a refresh clock of a RAM 2 outputted from a variable frequency oscillation circuit 4 controlled by a temperature detection means 5 is lowered. Thus, the power consumption of the backup battery 7 increasing the current consumption as temperature decreases is suppressed to extend the service life of the backup battery.
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