Power-white LED dimming detection system based on NC PWM

This paper introduces the design method of PWM control and detection system for the power intensity of white LED based on STM32F103RBT6 single chip microcomputer. The system consists of LM2576 DC / DC power module, single-chip control processing module, LED constant current drive circuit, light intensity detection module and liquid crystal display module. It uses STM32 micro-controller output PWM signal to control the constant current drive to achieve digital dimming. BH1750FVI light intensity detection module to detect the luminous intensity of white LED, and send STM32 after processing by LCD12864 display and make feedback adjustment. The experimental results show that the system can achieve effective PWM dimming, compared with the measured results of the illumination meter SPIC-200, the detection relative error is less than 8.70%.