| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a lighting device having a configuration that can be achieved with ease and at low cost, and in which a constant current property is not deteriorated even in the case that a load is different.SOLUTION: A lighting device comprises: a flyback converter circuit 3a having a transformer T1, a switching element Q1, an output capacitor C2, and a diode D1; a control circuit 5 on-off-controlling the switching element Q1; and an output connector CON2 that can exchange a semiconductor light-emitting element 4 that is a load. In the lighting device, the control circuit 5 comprises: means (a current detection resistor R1 and a chopper current detection terminal CS) of turing off the switching element Q1 when an instantaneous value of a gradually increasing current flowing in a primary coil n1 of the transformer T1 at an on state of the switching element Q1 reaches a predetermined value; and means (a tertiary coil n3 of the transformer T1, and a zero-cross detection terminal ZCD) of turning on the switching element Q1 when a gradually decreasing current flowing in a secondary coil n2 of the transformer T1 at an off state of the switching element Q1 becomes substantially zero.</p> |
