Research And Design Based On Tapped Buck Thyristor Dimming LED Driver

With the continued development of science and technology as well as increasingly serious global pollution,the invention of LED is a historic leap in human history.Nowadays society advocates energy conservation and environmental protection.Thanks to their time-honored development and mature technology,TRIAC dimmers can be seen everywhere which have realized a perfect combination with traditional incandescents and halogen lamps in the current lighting market.In order to successfully expand the market,it has become a must for LED lighting replacement lamps to adopt existing TRIAC dimmers and control lines so as to achieve dimming effects.However,the biggest problem for TRIAC Dimmable LED lighting lies in the compatibility between the LED driver and dimmer.Therefore,it is of great theoretical and practical value to design a LED driver which is compatible with various TRIAC dimmers based on research and design of TRIAC Dimmable LED Driver.The paper begins with a description of the background and significance of the subject research and makes an in-depth analysis of the basic principle,control type,working mode,topological structure and power factor correction technique of switching power supply.Meanwhile,the advantages and disadvantages of TRIAC dimmers are discussed in detail.In order to realize a better compatibility between LED driver and TRIAC dinmmer,a suitable-for built-in bulb TRAIC dimmable driver-has been produced with LYT4311E as the main chip in this subject research based on the above theoretical basis.In this subject research,the driver is designed by combining the single-stage power factor correction with the accurate constant current(CC)output with its circuit adopting a non-isolated tapped-buck topological structure.Tapped-buck topological structure can effectively reduce the magnetic-leakage loss of the transformer so as to improve the driver's work efficiency.When the TRAIC dimmer works with the LED driver,flashing LED problems may be easily caused.In order to overcome this shortcoming,this paper conducts special designs of active damping circuit and passive discharge circuit so that the main chip,topological structure and circuit design can be perfectly combined.Then it designs appropriate transformers and components for choice according to theoretical analysis and calculation,and ends with a simple EMI filter design.In this subject research;a TRIAC Dimmable LED Driver with its input voltage of 190?265VAC and output voltage of 41V/350mA is produced.In the actual design process,a prototype meeting the design requirements was ultimately made after a number of debugging and calculation.The prototype has an ultimate efficiency of above 0.9 in 220VAC and PF value of above 95%in the long-term work.In this paper,a test analysis is also made of the prototype's key parameters including basic performance and dimming performance.The test result shows that this prototype can be compatible with a variety of TRIAC dimmers and enjoys high application value.