Lighting device and lighting fixture

Abstract

To reduce the possibility that overvoltage is applied from an AC power supply to a circuit subsequent to a step-down chopper circuit.SOLUTION: A lighting device 2 comprises a full-wave rectifying circuit 4, a first capacitor C1, a first conversion circuit 5, a second capacitor C2, a second conversion circuit 6, a protection circuit 9, and a cut-off circuit 13. The full-wave rectifying circuit 4 outputs a pulsating voltage obtained by subjecting AC voltage to all-wave rectification. The first conversion circuit 5 is a step-down chopper circuit that lowers the pulsating voltage smoothed by the first capacitor C1. The second conversion circuit 6 converts first DC voltage input to a pair of third input terminals 61 into second DC voltage different from the first DC voltage, and outputs the DC voltage to a pair of third output terminals 62. The protection circuit 9 is connected between a pair of second output terminals 52, and when a potential difference between the pair of second output terminals 52 exceeds a predetermined value, short-circuits between the pair of second output terminals 52. The cut-off circuit 13 cuts off an electric path 14 through which AC voltage is input from an AC power supply PS.SELECTED DRAWING: Figure 2

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