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

摘要

An LED drive circuit in which an alternating voltage from a phase control dimmer is input and an LED is driven. The LED drive circuit comprises a phase angle detector for detecting the phase angle at which a phase control element inside the phase control dimmer switches from off to on; a switching power supply for feeding a current to the LED; a switching element connected in series to the LED; and a controller for controlling the switching power supply and the switching element in accordance with the output of the phase angle detector; wherein the controller places the switching element in an always-on state in a case in which the phase angle detected by the phase angle detector is equal to or less than a predetermined value, and the controller pulse-drives the switching element in a case in which the phase angle detected by the phase angle detector is greater than the predetermined value.