Research And Design Of Switch Power Supply To Drive High Power LED

LED lighting becomes the future development trend of the lighting in the lightingarea with energy saving, environment protection, light effect strong, long life, small size,low driving voltage, mercury pollution. But the LED power of working conditionsseverely restricts the development of the LED in conversion efficiency and harmonicpollution. LED power supply in current harmonics must meet the C–class standards ofGB17625.2-2007. so high power factor, high efficiency LED power supply is necessaryto endure that LED successfully enter the general lighting market.In order to improve the efficiency of the LED power supply,, the LED powersupply power factor values, under the premise of considering the cost of LED lightingapplications, this paper presents the application of Single-stage power factorcorrection(PFC) technology in the LED power.Firstly, compare the characteristics of the passive power factor correction circuit,the Single-stage power factor correction circuit and the bipolar power factor correctioncircuit, demonstrate the superiority of the application of uipolar PFC in LED power, andchoose Single-stage PFC circuit structure. Secondly, analysis the current operationmode of PFC loop control to provide a theoretical basis for the selection of the controlchip. And combining with the working principle of the control chip and therequirements of the constant current limiting voltage output of LED power, design themaster of the monopole PFC Flyback LED power circuit. This paper also analyzes thework principle of high-frequency of the Single-stage PFC Flyback LED power. With therequirements of high efficiency and low EMI, designs parameters of the transformer,and derivate the twice power frequency output voltage ripple inherent by Single-stagePFC circuit, designs the rational filter circuit of the output voltage.Referring to the above theoretical analysis and operational parameters, this paperproduces a90W Flyback LED drive power. The output voltage and current is28V/3.3A.And tests the voltage and current waveforms of the design circuit. The experimentalresults shows that, the LED power designed in this paper can effectively improve thepower factor, reduce the pollution of the current harmonic to power.