| 摘要 |
PROBLEM TO BE SOLVED: To improve power exchange efficiency for reduction in the current consumption of a battery and prolong backup time, by giving a difference in the output voltage of a power supply unit for control at the time of battery backup, keeping one of the power supply voltages under no-load operation, and supplying load current from a main power supply unit alone. SOLUTION: A backup battery 2 is connected to the output of a power supply unit 1 serving as a charger, and the first power supply unit 3 and the second power supply unit 4 are parallel-connected to each other. A redundant operation structure is formed which a battery on one side continues power feeding to a load on one side even if a battery on the other battery stops. After a backup condition from the battery 2 is reached, the first power supply unit 3 is changed so as to be a little higher than in an ordinary case, and the second power supply unit 4 is changed so as to be a little lower than in an ordinary case. As a result, the current to a load shared by the two power supply units 3, 4 is supplied from the first power supply unit 3 alone. The second power supply unit 4 becomes a standby system under a no-load condition. |
