LED DRIVE CIRCUIT, DIMMING DEVICE, LED ILLUMINATION FIXTURE, LED ILLUMINATION DEVICE, AND LED ILLUMINATION SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide an LED drive circuit capable of reducing flickering during low-brightness dimming of an LED.

SOLUTION: The LED drive circuit in which an alternating voltage from a phase control dimmer 2 is input and an LED (an LED module 3) is driven includes: a phase angle detector 7 for detecting a phase angle at which a phase control element inside the phase control dimmer 2 switches from off to on; a switching power supply section 5 for feeding a current to the LED; a switching element 6 connected in series with the LED; and a controller 8 for controlling the switching power supply section 5 and the switching element 6 in accordance with an output of the phase angle detector 7, wherein the controller 8 places the switching element 6 in an always-on state in case the phase angle detected by the phase angle detector 7 is not more than a predetermined value, and the controller 8 pulse-drives the switching element 6 in case the phase angle detected by the phase angle detector 7 is greater than the predetermined value.

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