| 摘要 |
PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device and a lighting fixture using the same capable of avoiding flicker and fadeaway of a discharge lamp, even in case light control is carried out to lower an optical output for a discharge lamp with a high load impedance. SOLUTION: The device comprises an inverter circuit 1 supplying direct-current voltage converted into high-frequency alternating-current voltage to a load circuit 2 including a discharge lamp La, a current-detecting circuit 3 detecting a load current flowing in the discharge lamp La, a target value setting circuit 4 setting a target value S2 of an optical output of the discharge lamp La in accordance with light-control signals sent from an outside light controller LC, a feedback control circuit 5 carrying feedback control by varying frequencies of output voltages of the inverter circuit 1 so that a detected vale S1 is kept at the target value S2 in comparison of the latter S2 with the former S1 outputted from the current-detecting circuit 3, and a light-control state detecting circuit 6 comparing the target value S2 with a partial pressure value S4 of an output value S3 of a first comparator OP. The instant the partial pressure value S4 goes beyond the target value S2, the latter S2 is fixed. COPYRIGHT: (C)2009,JPO&INPIT |
