LIGHTING DEVICE AND LUMINAIRE HAVING THE SAME

PROBLEM TO BE SOLVED: To widen a dimming range of a light source load in a relatively simple configuration.SOLUTION: A control circuit 4 selects a first control mode of turning on/off a switching element 162 such that a current flows through an inductor 163 without any quiescent intervals, to fully...

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Bibliographische Detailangaben
Hauptverfasser: HIRAMATSU AKINORI, EZAKI SANA
Format: Patent
Sprache:eng
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Zusammenfassung:PROBLEM TO BE SOLVED: To widen a dimming range of a light source load in a relatively simple configuration.SOLUTION: A control circuit 4 selects a first control mode of turning on/off a switching element 162 such that a current flows through an inductor 163 without any quiescent intervals, to fully light a light source load 3. The control circuit 4 selects one of a second control mode of changing an on time of the switching element 162 and a third control mode of changing an oscillation frequency thereof in accordance with an interval to which a specified dimming ratio corresponds, to dim the light source load 3. An output capacitor 164 connected between output ends of a step-down chopper circuit 16, which smoothes a pulsation component of an output current supplied to the light source load 3, has a capacitance set such that a ripple rate of the output current is less than 0.5 when the light source load 3 is fully lit.