| 摘要 |
PURPOSE: To reduce distortion of input current, reduce harmonics and make the starting reliable by providing a start circuit in a switching circuit, by feed back part of output based on alternate switching of a pair of switching circuits and by turning on and off a pair of switching circuits. CONSTITUTION: When a switching element 16 turns on at the output of a time constant circuit 15 of a start circuit 14, a switching circuit 5 turns on. Output of secondary windings 13-2 and 13-3 of a current transformer 13 turns on the switching circuit 5 and turns off the switching circuit 6 since the current flowing to the primary winding 13-1 is large. When the current transformer 13 is saturated and the output of the secondary winding 13-2 disappears, the switching circuit 5 turns off and the switching circuit 6 turns on. Next, when the switching cicuit 5 turns on, voltages across capacitors 11 and 8 begin to drop, so that a current flows from a rectifier circuit 4 to capacitor 8. By flowing this charging current, input power factor can be improved so that a smaller distortion of input current can be achieved. |
