| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a lighting device of a semiconductor light-emitting element which achieves a stable dimming lighting from an extremely weak optical output to rating lighting by using a switching power supply that operates in a discontinuous mode. <P>SOLUTION: A device subjects a semiconductor light-emitting element 4 to dimming lighting by a DC-DC converter 3 that operates in a discontinuous mode. The device includes: a burst dimming control section that controls a current passing through the semiconductor light-emitting element 4 by intermittently stopping an on or off operation of a switching element Q1; output detection sections 5a and 5b for detecting at least one of the current passing through the semiconductor light-emitting element 4 or an applied voltage thereto; and a feedback control section 6 for adjusting a turn-on period or a burst dimming period of the switching element Q1 during the on or off operation, in a direction in which detection values of the output detection sections 5a and 5b approach a target value. A power feeding to the feedback control section 6 may be stopped in the vicinity of a dimming lower limit. <P>COPYRIGHT: (C)2013,JPO&INPIT |
