自动化专业毕业论文--大功率LED恒流开关电源的研制.doc

摘要
目前,电能的合理利用越来越成为节约能源的重要方面。LED由于其节能、高效、高稳定性、长寿命等特点,得到越来越广泛的应用。LED 本身的光学特性对电流的敏感性高于电压。由于LED的这些特点,一种与之匹配的高效、节能、稳定的电源必不可少。
本文设计了一种市场需求量大的拥有多路输出的大功率LED恒流驱动开关电源,它在输入电压和负载LED灯串电压(即个数)在一定范围内变化时,仍具有高恒流精度和控制结构简单、成本低、体积小、效率高等特点。文章首先对大功率照明LED的特性及其驱动电路的性能要求进行了介绍。接着分析了恒流开关电源作为LED驱动电源的可行性及优势所在,介绍了开关电源相关关键性技术,确定本设计采用反激式的括扑结构,驱动电路采用先恒压再恒流的两级驱动形式,控制芯片使用 PI 公司的 TNY274 系列控制芯片。然后,论文对开关电源各个功能模块进行了设计并通过公式推导计算出最佳参数作为设计参考。最后整合各功能模块,设计出两级驱动 LED总电路,绘制出整体电路PCB图,并对本次设计进行了总结。
关键词:LED;恒流;开关电源;驱动电源;大功率

Abstract
At present, the rational use of electricity has increasingly e an important aspect of energy conservation. LED to be more widely used due to its energy saving, high efficiency, high stability, long life characteristics. Higher than the voltage of the current sensitivity of the optical properties of the LED itself. Because of these characteristics of the LED, a matching efficiency, energy saving, stable power supply is essential.
Design a market demand of high-power LED constant current driver switching power supply with multiple outputs, and change within a certain range in the input voltage and load LED string voltage (ie, number), still has a high current precision and control structure is simple, low cost, small size and high efficiency. The article introduces the first high-power LED lighting characteristics and performance of the drive circuit requirements. Then analyzes the feasibility and advantages of the constant-current switching power supply as an LED driver power supply, switching power supply key technologies to determine the design of flyback including flutter structure using two of the first constant voltage constant current drive circuit -driven form of control chip using the PI series TNY274 control chip. Then, the papers on the various functional modules of the switching power supply design and derived formula to calculate the optimal parameters as a design reference. The final integration of the functional modules, designed the two LED drive circuit, PCB plans