| 摘要 |
<p>PURPOSE:To operate a terminal device when a power failure occurs by automatically supplying a DC power source from a battery when an AC input power source is exhausted. CONSTITUTION:A converting circuit 1 converts an AC voltage into a DC voltage, and a battery 4 outputs the DC voltage lower than the DC voltage outputted by the converting circuit 1. In a synthesizing circuit 7, the DC voltage from the battery 4 becomes higher than that from the converting circuit 1 due to the cut of the AC power source, and the DC voltage from the battery 4 is made to pass. Consequently, when the AC power source is exhausted, the DC power source can be automatically supplied. Further, when a voltage drop detector 8 detects the drop of the DC voltage to be the output of the converting circuit 1, it notifies a DC voltage dropping signal to a CPU, and the current processing of the CPU is promptly completed. Thus, the processing of the terminal device can be prevented from being interrupted on the way and the destruction of the input data can be prevented from being generated.</p> |
