LIGHTING DEVICE

To provide a lighting device capable of reducing an output voltage of a step-up chopper circuit in a case where open failures are generated in a feedback circuit.SOLUTION: A lighting device 10 comprises: a step-up chopper circuit 30 that supplies a DC current to a light source 40; an overvoltage detection circuit 60 applied with an output voltage of the step-up chopper circuit 30; a constant current circuit 50 that maintains the DC current to a constant value; and a drive control circuit 90 that controls drive states of the step-up chopper circuit 30 and the constant current circuit 50. In a case where the output voltage is larger than a stop reference voltage, the overvoltage detection circuit 60 outputs a stop signal to the drive control circuit 90 to stop driving of the step-up chopper circuit 30 and the constant current circuit 50. After a predetermined delay time has elapsed from the time point when the output voltage becomes larger than the stop reference voltage and then becomes lower than the stop reference voltage, the overvoltage detection circuit 60 stops outputting the stop signal to resume driving of the step-up chopper circuit 30 and the constant current circuit 50.SELECTED DRAWING: Figure 1 【課題】フィードバック回路でオープン故障などが発生した場合に、昇圧チョッパ回路の出力電圧を低減できる点灯装置を提供する。【解決手段】点灯装置１０は、光源４０に直流電流を供給する昇圧チョッパ回路３０と、昇圧チョッパ回路３０の出力電圧が印加される過電圧検出回路６０と、直流電流を一定に維持する定電流回路５０と、昇圧チョッパ回路３０及び定電流回路５０の駆動状態を制御する駆動制御回路９０と、を備え、過電圧検出回路６０は、出力電圧が停止基準電圧を超える場合に駆動制御回路９０に停止信号を出力することで、昇圧チョッパ回路３０及び定電流回路５の駆動を停止させ、出力電圧が停止基準電圧を超えた後、出力電圧が停止基準電圧より低くなった時点から所定の遅延時間が経過した後に、停止信号の出力を停止することで、昇圧チョッパ回路３０及び定電流回路５０の駆動を再開させる。【選択図】図１