Discharge lamp lighting device and illumination fixture with end of life detection

摘要

[Object] To manage a life time regardless of an inputted voltage, and when the life time has expired, be able to notify the expiration. [Means for Settlement] A bias current Ibias flowing in accordance with the turning-on and the turning-off of switching elements Q1 and Q2 is applied to an electrolytic capacitor C1 via a diode D1 and a current-limiting resistor R1 to charge the electrolytic capacitor C1. The electrolytic capacitor C1 reduces an electrostatic capacity as time of use becomes long and increases an amplitude of a ripple voltage. After a life time detection circuit 14 detects the ripple voltage at both ends of the electrolytic capacitor C1 and the detected voltage is compared to a predetermined threshold value V_LSL, an instruction to change an operating frequency is outputted to a frequency control circuit 131 when the detected voltage exceeds the threshold value V_LSL. A lighting control circuit 13 changes the operating frequency on the basis of the instruction from the life time detection circuit 14 to control a discharge lamp FL to be brighter than or to be dimmed less than a normal state.