Modular Design Of UV LED Drive System

The Ultraviolet light-emitting diode UVLED has the characteristics of high luminous efficiency,sturdiness and reliability,long life and fast switching speed.Although the performance of UVLED is degraded,UVLED has many unique and excellent properties compared with traditional ultraviolet light sources,so that it can be used as a key component.In many new industrial applications.The application of UVLED needs to be supported by a drive power supply with stable constant current output.The core of the UVLED drive power supply is the DC drive circuit,which mainly adopts the modular design method when designing the circuit.Switching conversion circuits have become the mainstream form of UVLED drive power.The energy conversion efficiency of the switching conversion circuit can reach more than 90%.Industrial applications of UVLEDs require high light output power and adjustable power.In this paper,in order to develop industrial UV light source modules,the UVLED drive system includes modules such as light source,drive,control,and feedback.Developed with light source output power of 200 W,400W,and 600 W.It is planned to use 40 W or 50 W high-power integrated package products as the ultraviolet light source to design the UVLED drive system.The UVLED light source module adopts a constant current drive mode,and the drive current needs to be variable,that is,it has a dimming function,and can automatically balance the power output by using the optical power signal feedback from the photoelectric sensor.The overall design of the UVLED drive system is divided into three modules: DC drive and light source module,photoelectric detection module,and MCU control module.The DC drive and light source module consists of a UVLED light source and a DC-DC DC drive circuit.The DC-DC DC drive directly supplies power to the UVLED light source.This module is the core of the entire system.Using Boost boost switching circuit and LT3756 chip as the main control chip to design the dimmable DC drive circuit.Ultraviolet photodetection uses ultraviolet photodiodes to convert the light signals of UVLEDs into electrical signals.The electrical signals are filtered and amplified by an integrated operational amplifier and output to ADC for sampling.The MCU control module converts the electrical signal output by the ultraviolet photodetection module into a digital signal through the analog-to-digital converter ADC,and performs arithmetic conversion of the digital signal to control the PWM dimming signal,thereby controlling the output current of the DC drive and the output light power of the UVLED.The entire UVLED drive system forms a closed-loop control.The photodetection module and the MCU control module adjust the output current of the UVLED by detecting the light power output by the UVLED,which plays a role of feedback and adjustment.Using LTspice software to simulate the Boost boost drive circuit,the influence of the change of component parameters on the output current of the circuit is analyzed.Use MCU hardware development platform,Keil ?Vision5 integrated development environment and STC-ISP software to carry out software test and hardware online test for MCU control program.The filter circuit in the UV photoelectric detection module of LTspice software is used for simulation analysis.The design function of the UVLED drive system is verified by the above simulation test.