A Research On LED Drive Power Without Electrolytic Capacitors Based On Flyback Converter

As a new solid-state light source,compared to traditional fluorescent lamp and incandescent lamp,LED has significant advantages such as high efficiency^ small size、long life、environmental protection、energy saving and so on,it is widely used in residential and commercial lighting. LED’s life can theoretically reach to 100,000 hours,whereas in real life,it’s reduced due to the life limits of LED drive circuit’s electrolytic capacitor. The purpose of this paper is to reduce the value of the storage capacitor’s capacitance without affecting the drive circuit working,enabling replaced electrolytic capacitor with ceramic capacitors or film capacitors to improve the life of the LED drive circuit.Firstly,this paper introduces three typical LED drive circuit: boost,buck,flyback.Flyback driver circuit with electrically isolated is used as my design’s power supply topologies combined with the actual needs of the design.Analyzing flyback converter operational state under different operating modes.Also analyzing principle and realization method of remove the electrolytic capacitor. Secondly,make a detailed theoretical analysis and calculation for the EMI filter and rectifier circuit、power factor correction circuit、drain clamp protection circuit、energy storage module circuit、LED series protection module and transformer design involved in the LED drive circuit.Then,derive and calculate parameters of PID controller inside the feedback control circuit,and choose UC3842 control chip to achieve feedback control.Finally,using Multisim circuit simulation platform to build LED drive power without electrolytic capacitors based on flyback converter circuit.Simulation circuit effectively make storage capacitor value drops to 2μF,output current ripple is 10%, The results show that this design can meet the performance requirement of the LED driver.