一种基于FAN6754A的PWM反激式开关电源的设计

Design of PWM Flyback Power Supply by Using FAN6754A

介绍了新款峰值电流型PWM控制芯片FAN6754A的工作特性和原理,分析了反激式开关电源的设计原理以及工作过程。针对次级电路结构,设计了一种新型反激式开关稳压电源。着重介绍了反激式开关电源的变压器设计过程,包括电感值的计算、磁芯的选择、绕组匝数的确定以及气隙等。利用三端稳压器TL431配合FAN6754A实现了对电源电压的控制和稳压输出,采用光耦器件实现了输入/输出的隔离和反馈。并在电源电路中加入了热敏电阻以及过压、过流保护等保护措施。实验测试结果表明:所设计的电源效率接近89%、稳压性能优良、纹波小、电压调整率、负载调整率高等优点。

The working characteristics and principles of a novel peak current-mode PWM IC FAN6754A are described. The analysis is put forward of design principles in operating process of flyback switching power supplies. A novel flyback switching power supply is provided to meet the needs of the secondary circuit, with emphasis on its transformer design including inductance current, transformer type, windings and gap length etc. The voltage control and stable output are realized by using three-terminal voltage regulator TIA31, input/output isolation and feedback with opti-coupler. Its design principle, module functions and working process are analyzed. And in the circuit there exists thermistors, over-vohage, and over-current protection etc. Experimental results show that the designed converter has the characteristics of efficiency of near 89%, steady, low voltage ripples, high load regulation rate and voltage adjustment rate etc.