| 摘要 |
PROBLEM TO BE SOLVED: To provide a lighting device which can light up a light-emitting element to a deep light control level and can smoothly change the brightness of the light-emitting element over a wide range, and a luminaire using the same.SOLUTION: A lighting device 1 comprises a first current adjustment part 123 for adjusting the current flowing in an LED 31 by turning on/off a transistor Q2 according to a PWM signal S3 in which the on-duty ratio changes in response to the light control signal S1 from outside; and a second current adjustment part 122 for adjusting the current flowing in the LED 31 by changing the voltage applied to a gate of the transistor Q2 according to the light control signal S1. When the light control level by the light control signal S1 is a predetermined value or more, the second current adjustment part 122 controls the brightness of the LED 31, and when the light control level is less than the predetermined value, a control state controlled by the second current adjustment part 122 when the light control level is the predetermined value, is kept and the brightness of the LED 31 is controlled by the first current adjustment part 123. |
