DISCHARGE LAMP LIGHTING DEVICE, AND LIGHTING FIXTURE

摘要

PROBLEM TO BE SOLVED: To restrain effect to an emergency power source and the other devices while securing indispensable brightness when operating at a low power supply voltage environment where the emergency power source is used.

SOLUTION: An inverter type discharge lamp lighting device comprises an input voltage detection means for detecting input voltage Vin, and an output control means (inverter control circuit 4) for controlling output of a discharge lamp La in response to at least the input voltage Vin. The output of the discharge lamp La is controlled to keep at a fixed level in spite of power source voltage until the input voltage Vin is reduced to a first input voltage threshold Vth1b, the output of the discharge lamp La is controlled so as to make input current become a designated value or below when the input voltage Vin is lower than the first input voltage threshold Vth1b and is equal to or higher than a second input voltage threshold Vth2, and an inverter circuit 3 is stopped when the input voltage Vin is equal to or lower than the second input voltage threshold Vth2.

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