Research On LED Driver With Multiple Dimming Functions

Entering the 21st century,the energy crisis is one of the major challenges people all over the world are facing.Lighting power consumption accounted for a larger proportion of energy consumption,the use of energy-efficient lighting power supply can significantly reduce the energy consumption,contribute to energy saving.LED as the fourth generation of lighting with high luminous efficiency,energy saving,long life,etc,are widely used in road lighting,factory lighting,home lighting and other lighting applications.Applying a variety of dimming techniques in the field of LED lighting can not only further reduce energy consumption,but also improve visual effects.Therefore,it is significant to study the LED driver with dimming function.The thesis firstly analyzes the characteristics of LED electric light source and the research status of LED driving power source.Then it introduces the LED driving power topology,LED dimming technology and power factor correction technology.Based on this,the main research contents of this paper are presented.According to the working characteristics of TRIAC dimmer and LED light source,a TRIAC dimming LED driver which can be integrated with other dimmers is studied and designed.In order to restrain the problem of flicker,the paper adopts the two-stage converter circuit composed of PFC circuit and flyback converter as LED driver circuit structure,selects IW3631 as the control chip,and realizes the constant current and dimming control of LED lamp.In order to integrate with other dimming circuits,the conduction angle of TRIAC dimming is converted into PWM dimming signal through phase angle detection.In view of the inherent defects of TRIAC dimming,the present invention solves the problems of active bleeding in hardware Dimming process,especially the dirmming problem of low brightness dimming,solved the TRIAC dimming conduction angle and LED load matching problem by the anti-dithering process in the software,and realized the smooth dimming of the LED.The components of TRIAC dimming LED driving power and the design process of hardware and software are introduced in detail,and the design and calculation of the key parameters of the circuit are carried out.According to different dimmers and dimming methods,research and development can be compatible with TRIAC dimming,0-10V dimming,Bluetooth dimming,DALI dimming and other functions of the drive power,through these dimming technology Organic blend together to achieve a variety of dimming methods can be independently dimming,but also can be combined dimming,with energy saving,high efficiency,flexible operation and so on.Finally,a prototype of 28 W LED driver with a variety of dimming functions was developed for experimental testing.The experimental results verify the feasibility of the proposed scheme.