Patent ID: 8692469

Claim:
An LED drive circuit which is connectable to a phase control type light adjuster and into which an input voltage based on an a.c. voltage that undergoes phase control performed by the phase control type light adjuster is input to drive an LED load, comprising: an LED drive portion that drives the LED load; a phase angle detection portion that detects a phase angle based on the input voltage; a first reference voltage generation portion that generates a first reference voltage; a second reference voltage generation portion that generates a second reference voltage in accordance with the phase angle detected by the phase angle detection portion; an input voltage detection portion that detects a size relationship between the input voltage and a threshold value voltage; a current draw-out portion that draws out a current in accordance with the first reference voltage or the second reference voltage from an electricity supply line that supplies electricity to the LED drive portion; and a switch portion that in accordance with a detection result by the input voltage detection portion, performs switching between an output from the first reference voltage generation portion to the current draw-out portion and an output from the second reference voltage generation portion to the current draw-out portion.