Light-adjustable LED drive circuit

The utility model discloses a light-adjustable LED drive circuit. The circuit comprises a constant current unit, a PWM signal light adjusting unit and a controlled switch unit, wherein the constant current unit is used for generating a constant current, the PWM signal light adjusting unit is used for generating a PWM signal of adjustable duty ratio for controlling the conduction time of an LED load; an input end of the constant current unit is connected with an external power supply, and an output end is connected with a positive end of the LED load; an input end of the PWM signal light adjusting unit is connected with the external power supply, and an output end is connected with a control end of the controlled switch unit; an input end of the controlled switch unit is connected with a negative end of the LED load, and an output end is coupled with an earth potential. The drive circuit supports the PWM light adjusting way and the linear light adjusting way, thus the drive circuit has features of low cost, simple circuit, high constant current precision, high reliability, no flashing of the LED, and high efficiency.