| 摘要 |
PROBLEM TO BE SOLVED: To switch a commercial power supply operation to a battery operation without an instantaneous break when a commercial power supply is interrupted, while the discharging of a battery is suppressed, during commercial power supply operation. SOLUTION: A battery start-up circuit supplies a power to a load device which can be made to be operated through either one of a commercial power supply 1 and a battery 2. A DC power output E2 of a power supply unit 3 is supplied to the load device and is also connected to the output of a battery 2 via a diode 8. A controllable switch 15 is inserted into the output circuit of the battery 15. A voltage detector 13 is provided, and the switch 15 is controlled to be turned off when a battery voltage is lowered below the discharge terminating voltage of the battery 2. Furthermore, a controllable switch 16 is inserted into a path between the battery 2 and the voltage detector 13, and when the voltage detector 13 detects the battery voltage lower than the discharge terminating voltage of the battery 2, not only the switch 15 but also the switch 16 is controlled to be turned off. |
