Research And Design On Wide Output AC-DC LED Driver Power

Since the 21 st century,energy and environmental crisis are important issues faced by human survival and development.Therefore,improving energy efficiency is one of the important means to solve energy and environmental issues.LED as the fourth generation of green lighting source,it has the advantages of low power consumption,energy saving,safety,environmental protection,long life,high brightness,becoming one of the world's most promising high-tech.The innovation of green light source is changing the centuries-old history of traditional lighting.LED's brightness and life are directly related to the LED drive power supply,Many LED power supplies on the market have disadvantages such as short life,low power factor and high energy consumption which limit the application and development of LED.Thus,it is of great value to develop LED driving power supply with LED characteristics,high power factor and small energy consumption.Aiming at the issues of LED driver,this paper studies and designs a two-stage structure of constant voltage and constant current drive power supply,the front-stage is power factor correction current and the back-stage is Buck-Boost converter.The front-stage circuit is designed to improve the power factor of the power supply system and provide a stable DC voltage for the back-stage Buck-Boost converter.The back-stage Buck-Boost converter is designed for voltage adjustment and constant current output.In order to reduce switching losses and improve the effect of energy saving and environmental protection,passive and lossless soft switching technology is added to the back-stage buck-boost circuit of the designed LED driver,eliminate to and suppress di/dt and dv/dt interference generated by semiconductor switching devices,improve the energy conversion efficiency of power supply.At the same time,to solve the problem that LED requires constant current drive,adopt to current type PWM control technology realize constant current output and has over-current protection function.The response speed of the system is about twice that of voltage type PWM control technology.In this paper,the power factor correction technology,soft switch technology and currenttype PWM control technology involved in LED driving power supply are analyzed and studied in depth.And the simulation circuit is built based on PSIM(Power Simulation)simulation software,finally,Using UCC28019 and UC3843 control chip to make an LED drive power supply with input voltage ranging from 15 VAC to 36 VAC and constant current output.The simulation and experiment prove that the LED driving power supply developed in this paper has the characteristics of fast response,constant output current,Small switching loss,high power factor and has strong practical value.