Research And Design Of Novel LED Power Supply Based On LC Parallel Resonant

Along with the gradually withdraw of the electronic ballasts for fluorescent lamps frommarketing, high performance LED power supplys are widely used. Active power factorcorrection technique can make the current follow up the voltage and reduce the harmonic inthe power supply, therefore it can be used to improve the efficiency of LED power driver.Resonant converter has been widely used in the LED power driver due to the advantage ofhigher operation frequency, lower switching loss, higher efficiency, smaller volume, etc.There are three types of topology for nowaday’s resonant converter, they are LC seriesresonant, LC parallel resonant and LC series-parallel resonant. Due to it is hard to control atload open and short condotion series resonance is mainly used in low power compact LEDlamp, because of its high efficiency, constant current output, high precision series parallelresonant structure is widely used in the indoor lighting, screen display and color projectorwhich request more accurate constant current output occasion to provide high power LEDdriver.With the rapid development of LED lighting, requirements of LED driver must notonly can provide high power, but also has high reliability and is easy to realize multi channeloutput etc, at this point originally used in the current type parallel resonant which is uesdfluorescent lamp before has more advantage. This paper aimed at the demand of the highpower LED street lighting, self activate current type parallel resonant topology on earlyapplication in fluorescent lamp ballast is improved, proposes a driving scheme for LED streetlighting,it has the advantages of simple structure, high reliability, multi channel independent.And also discussed contradiction between small starting resistance could be large powerconsumption and larger starting resistance increases power starting time in the active powerfactor correction circuit commonly used at present, put forward a kind of improved startingcircuit, at the same time achieve shorter start-up time and lower power consumption. Finally,the above two kinds of innovative research results based on the design of a new type highpower factor LED is composed of input power factor rectifier circuit, the improved correctioncircuit, parallel resonant network, current selection control circuit, output rectifier filtercircuit.This paper discussed working principle of improved power factor correction circuit andLC parallel resonant,By concluding the influence brought on the power factor correctioncircuit and converter by several parameters, the method of designing parameters of powerfactor correction circuit and converter are put forward. And with a25W LED driver based onimproved power factor correction circuit and a compact60W LED driver which based on LC parallel resonant for validation. Subsequently, much experimental data is given to testify thevalidity of the design method. The experimental results show that the efficiency of powersupply using a new power factor correction controller starting circuit is improved by0.8%,and the start time was reduced from275ms to154ms. New LED power supply does not needcomplex feedback control at the output can realize quasi constant current output, as long asthe increase of the output capacitor multi channel output can be realized, the change in outputcapacitance can achieve the current selection, which greatly reduces the design difficulty. Inthree channels output, a60W power supply can be successful, the total efficiency can reach88%, the ripple of output current is as low as3.4%, it is suitable for high power constantcurrent accuracy requirement of multi channel LED lighting driver.