| 摘要 |
PROBLEM TO BE SOLVED: To restrain power consumption under a condition that an external circuit is operated on a low current without using a backup battery. SOLUTION: A power circuit which supplies power to the external circuit having a condition where it operates on a normal current and a condition where it operates on a low current comprises a switching regulator, a large-capacity capacitor for storing and discharging the output of the switching regulator, a voltage monitor IC for monitoring the output voltage of the large-capacity capacitor and detecting whether the external circuit is under the condition where it operates on a normal current or under the condition where it operates on a low current through a signal line from a control CPU. Under the condition where it operates on a low current, an output of roughly 10 ms is given to the switching regulator for a prescribed period when the monitored voltage of the voltage monitor IC 7 becomes at or less than 5.5 V, thus intermittently operating the switching regulator. |
