A Design Of Load Adaptive High-power LED Driver Based On The On-time Control

This thesis researched basic composition and working principle of high-power LED drive circuit that on the basis of analyzing the principle and characteristics of it.Then put forward a high-power LED drive circuit based on SSL4120 T chip after analysed different type drive circuit.The AC-DC stage of project is on the basis of boost topology, adopted Critical-conduction Mode operation with constant on-time control to achieve Power Factor Correction function.While use the Half- bridge LLC Resonant Converter and synchronous rectifier in the stage of DC-DC,that primary side MOSFET could realized Zero Voltage Switch and secondary side is synchronous rectification,improved system efficiency by reduced rectifier losses.The main work will carry out during project research follow the steps bellow:(1)Design the system structure and select control chip;(2)Research and analysis the PFC technology and choose control method that suitable for the project;(3)Study and research LLC circuit, established FHA equivalent model, design resonant transformer;(4)Design synchronous rectifier;(5)Make a high-power LED driver prototype, test it’s performance to verify the correctness of theoretical analysis.