| 摘要 |
PURPOSE:To switch a power supply from a commercial AC power supply to a battery quickly when the service of the commercial power supply is interrupted by a method wherein an output is supplied by the commercial AC power supply in an ordinary state and, when the service is interrupted, the output is supplied by the battery. CONSTITUTION:In an ordinary state wherein a commercial AC power supply 1 is normal, the AC of the commercial AC power supply is rectified by a rectifying circuit 2, smoothed by a smoothing capacitor C3, etc., converted into a radio frequency AC by an inverter part 3 and one (FL1) of discharge lamps is lit. A noncontact current detecting and switching means 12 turns a transistor Q4 off and discontinues the oscillation of an inverter part 6. A battery 4 is charged by the commercial AC power supply 1. If the service of the commercial AC power supply 1 is interrupted, a switch 9 is closed and the charge of a capacitor C16 is discharged. With this constitution, the charge of the smoothing capacitor 16 is discharged immediately after the service interruption and a current is applied to the noncontact current detecting and switching means 12 and the delay of an operation can be avoided. |
