Design and implementation of control method for LED driver based on light intensity feedback

Traditional control method of LED driver is mainly based on current control mode. Due to the nonlinear characteristics of V-I curve, conventional control methods are more suitable for steady-state control. Meanwhile, the illumination of LEDs is affected by temperature and the distance of the light source. In this paper, a control method with light intensity feedback is proposed to ensure the good performance of illumination. In addition, a fuzzy PID control strategy is employed to improve the LED driver's steady-state accuracy and dynamic performance. The mathematical model of LED driver based on buck converter was built, and the transfer function was derived. An experimental prototype was built to implement the proposed LED control scheme. The light intensity accuracy is limited to 5% when the load varies between 50 and 100%. The simulation model and the experimental prototype verify the feasibility of the LED illumination control method and the optimization of the fuzzy PID control.