Research On Adaptive Wide-voltage Range LED Linear Drive Power Supply

Semiconductor lighting uses LED(Light Emitting Diode)as the light source.With its advantages of green environmental protection and low carbon energy saving,it is gradually replacing traditional lighting.With the increasing awareness of energy saving and environmental protection,the application of LED lamps has become more popular.LED drive power,as a key component of LED lamps,its performance directly affects the performance and service life of LED lamps.Therefore,it is very important to carry out research on LED drive power.This article refers to the research shape of this field at home and abroad,and specifically analyzes the working principle,connection mode and driving technology of LED.Comprehensive analysis of traditional driving methods,combined with the advantages of wide input voltage range of switching regulators and pure output current of linear regulators,a new method for linear driving of wide voltage range LEDs based on adaptive series / parallel conversion is proposed.The series-connected constant current module and the LED load are evenly divided into several sections,and the different combinations of the switch array are controlled by the detection result of the input power voltage,thereby achieving the adaptive series / parallel connection of the constant current branch and the LED load,To ensure that the current flowing through each load is constant and the power of the total load is constant within a wide input voltage range.When the power supply voltage is higher,a constant current branch is controlled in series with all load branches;as the power supply voltage decreases,the load branch is correspondingly transformed into a hybrid connection form,there are several parallel branches in the load module,then Several constant current branches are connected in parallel in the constant current module;when the power supply voltage is low to a certain value,all constant current branches and all load branches are all connected in parallel respectively.Based on the proposed LED driving method,the separation circuit experiment was carried out.Within the working voltage range of 15?60V,four constant current branches and four load branches are connected in parallel at low voltage(15?24V),and two constant current branches are connected in series with two pairs at medium voltage(24?48V)After the load branches are connected in series,they are connected in parallel.At high voltage(48?60V),one constant current branch and all four load branches are connected in series.The experimental results show that the power of the LED load is constant within the operating voltage range of 15?60V.Finally,on the basis of the separation circuit experiment,it is expanded.Based on the 1um high voltage BCD process,an adaptive wide voltage range LED linear drive power chip suitable for commercial power input is designed.The circuit of each functional module inside the chip is designed,and the simulation analysis and optimization design are carried out based on CAD software.The simulation results of various indicators of the overall circuit of the chip meet the expected requirements and the design and verification of the chip layout are completed.