| 摘要 |
PROBLEM TO BE SOLVED: To drive a battery with the mode of comparatively smaller power consumption when the electric energy remains sufficiently in a backup battery and also to allow the self-recovery when a battery shutoff occurs in the backup battery. SOLUTION: By a logic control circuit 45, a battery discriminating circuit 46 and a power supply control circuit 34, a power supply changeover circuit 31 is controlled to drive a battery even with the mode of comparatively smaller power consumption when the electric energy remains sufficiently in a secondary battery 21, and also the whole power consumption is reduced since a switch control circuit 14 is controlled to stop the oscillation of a transformer 13. When a battery shutoff occurs, the switch control circuit 14 is controlled to start the oscillation of the transformer 13, and also the power supply voltage from a filter 15 is selected by the power supply changeover circuit 31 to allow the self-recovery. |
