| 摘要 |
PURPOSE:To reduce ripple component by operating choppers, having the same chopping rate, at equal phase intervals. CONSTITUTION:AC power from an AC power source 2 is converted to DC power by a rectifier 3, and the DC power smoothed by a smoothing capacitor 4 is applied to respective lamps 16, 26 via a first chopper 10 and a second chopper 20. The first chopper 10 is composed of a chopper transistor 11, a base driving circuit 12, an output-smoothing reactor 13, and a free wheel diode 14, and the second chopper 20 is also composed of in the same manner. The control circuit 30 of both the choppers 10, 20 is composed of current regulators 31, 33 and comparators 32, 34, a common chopping wave generator 35, and a common phase inverter 36. Then, the chopping frequency of the respective choppers 10, 20 is the same, and the choppers are controlled so that chopping may be performed with mutually equal phase difference.
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