介绍了一种以固定频率脉宽调制控制芯片SG3525为核心的低压大电流开关电源的设计方案,阐述了主电路的拓扑结构及主控制电路的电路设计。应用反馈手段和脉宽调制技术实现了电压、电流的稳定输出,并研制了一台18kW的样机。实验结果表明,该电路工作稳定,实用价值高,最后给出了具体的实验波形。 A design scheme of low voltage high current switching power supply with fixed frequency PWM controller SG3525 is introduced. The topology of the main circuit and the circuit design of the main control circuit are described. The feedback and pulse width modulation techniques were used to realize the stable output of voltage and current, and a 18kW prototype was developed. The experimental results show that the circuit is stable and has high practical value. Finally, the experimental waveforms are given.