| 摘要 |
PROBLEM TO BE SOLVED: To avoid the erroneous operation of a circuit due to rush current effectively and supply stable power supply to a load, by switching a built-in charging battery for backup at a receiving timing of light load, in case of power failure. SOLUTION: A logic circuit 28 takes a send-and-receive timing 23 and a power failure detection signal 24 as inputs from a send-and-receive timing forming circuit and a power failure detection circuit, and outputs switching signals 27, 29 to relays 25, 26. The outputs of the relays 25, 26 are supplied to a load part as a load side power source 14. By the power failure detection signal 24 and the send-and-receive timing 23 inputted in the logic circuit 28, the relay 25 is turned on and the relay 26 is turned off with a switching signal 29 in case of power failure, so that power (DC) 22 is supplied from a charging battery for performing backup. It is thus possible to avoid the erroneous operation of a circuit due to rush current effectively, thereby supplying stable power supply to the load. |
