| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to reduce an overvoltage of an output at recovering operation after power failure with respect to a power supply in communication equipment with a back-up battery and a load voltage compensator in an SID method. SOLUTION: A power supply 1 in communication equipment is set in a floating charging mode through a detection circuit 21 for detecting a voltage of a back-up battery 3 and generating an on-signal when the detected voltage is lower than a floating charge set value. As for a countermeasure at a recovery operation time after a power failure, a detection circuit 19 for detecting a voltage between output terminals 91 and 92 and generating an on-signal, when the detected voltage is over a given level, is provided. Then, an SID circuit 15 is inserted at a little earlier time by the signal, and after the output voltage is once reduced, an equalization charge mode is used to prevent an overvoltage of an output. In addition, an AC input voltage is monitored, and by counting a logical AND, the operation is carried out only when the output of a power failure open-phase detector 75 is in an on-state. |
