一种带PFC的反激式LED驱动电源芯片设计

发布时间：2018-01-17 14:16

本文关键词：一种带PFC的反激式LED驱动电源芯片设计　出处：《电子科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：作为第四代电光源照明的代表,LED绿色照明具有发光效率高、体积小、显色效果好、使用寿命长、环保等优点,将取代传统的电光源照明。但由于价格、LED照明技术等因素,尤其是与LED相匹配的驱动电源技术,制约着LED照明的普遍推广。LED驱动中,开关电源驱动器以其体积小、效率高且可靠性高等优点,而被广泛采用。本文设计了一种适用于中小功率、具有功率因数校正功能、采用原边反馈的反激式LED驱动电源芯片,该芯片采用隔离式反激变换器结构,使用上更加安全,输出电流能够达到370m A,电流误差低于3%,静态工作电流小于1mA,功率因数可达0.95以上,具有较高的电源效率,同时采用原边反馈,控制环路简单。且芯片工作在电流临界导通模式下,其输出电流纹波较小、EMI较小。本文根据实际应用要求,设定了芯片需要实现的功能,即恒定输出电流和功率因数校正,从而确定了实现功能所需要的各个功能子模块,并通过各种结构的对比,确定了电路的整体结构和工作模式。本文设计包括零电流检测和过压保护模块、电流峰值限制和锁存模块和逻辑控制模块。零电流模块检测副边绕组电流过零状态,控制电路工作在电流临界导通模式下;电流峰值限制和锁存模块一方面限制输入电流的峰值,且使输入电流与电压同相位实现功率因数校正,另一方面为电流运算模块提供电流峰值实现恒流;逻辑控制模块通过对各模块逻辑信号进行处理,控制芯片工作状态。在确定各子模块功能的基础上,对各子模块具体电路进行分析与设计,并通过仿真对子模块电路的功能进行验证,结合仿真结果对电路进行优化。最后综合所有模块,构建外围拓扑,对芯片整体电路进行仿真,仿真结果满足所设定的设计指标要求。
[Abstract]:Green lighting, which is the representative of 4th generation electric light source, has the advantages of high luminous efficiency, small volume, good color rendering effect, long service life, environmental protection and so on, which will replace the traditional electric light source lighting. But because of the price. LED lighting technology and other factors, especially the matching with the LED driving power technology, restrict the widespread use of LED lighting. Led driver, switching power driver with its small size. Because of its high efficiency and high reliability, it is widely used. In this paper, a flyback LED driver chip is designed, which is suitable for medium and small power, has the power factor correction function, and uses the original side feedback to drive the power supply. The chip adopts isolated flyback converter structure and is more secure in use. The output current can reach 370 Ma, the current error is lower than 3 Ma, and the static working current is less than 1 Ma. The power factor can reach more than 0.95, which has high power efficiency. At the same time, the control loop is simple by using the original side feedback, and the output current ripple is smaller when the chip works in the current critical conduction mode. The EMI is small. According to the practical application requirements, this paper sets the functions that the chip needs to achieve, that is, constant output current and power factor correction, so as to determine the functional sub-modules needed to achieve the function. Through the comparison of various structures, the overall structure and working mode of the circuit are determined. The design of this paper includes zero-current detection and over-voltage protection module. The zero current module detects the zero-crossing state of the secondary side winding current, and the control circuit works in the current critical conduction mode. On the one hand, the current peak limit and latch module limit the peak value of input current, and make the input current and voltage realize power factor correction in the same phase, on the other hand, the current peak value is provided to the current operation module to realize constant current. The logic control module controls the working state of the chip by processing the logic signals of each module. On the basis of determining the function of each sub-module, the specific circuit of each sub-module is analyzed and designed. The function of the sub-module circuit is verified by simulation, and the circuit is optimized with the simulation results. Finally, all the modules are synthesized, the peripheral topology is constructed, and the whole circuit of the chip is simulated. The simulation results meet the design requirements.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM923.34

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