本文介绍了以单片机AT89S52、光电脉宽调制器芯片TL494核心通过用单片机控制调节PWM 的方法，实现单片机控制的DC-DC开关电源电路系统；以及由数模转换芯片ADC0804等构成反馈以得到精确的电压输出的电路系统。由于单片机的电压不稳以及带负载能力不强，所以还包括单片机到DC－DC开关电源之间的稳压以及低通滤波的设计，ADC0804芯片外围电路设计，以及相关的调试与测试方法。-This paper introduces the single-chip AT89S52, photoelectric TL494 PWM chip core conditioning using single-chip PWM control method to achieve single-chip microcomputer-controlled DC-DC switching power supply circuit system　as well as by the number of chip-to-analog converter ADC0804 etc. in order to get accurate feedback voltage output of the circuit system. Voltage instability as a result of single-chip, as well as with the load capacity is not strong, it also includes the single-chip DC-DC switching power supply regulator, as well as between the design of low-pass filter, ADC0804 chip peripheral circuit design, as well as related testing and testing methods.