电压的步进调节就通过键盘进行步进调节，可以实现“+”、“-”的步进调节，电压调节的范围为0V~18V，可以电压细调（即每步进为0.05V）和电压粗调（即步进为1V），A/D、D/A转换电路主要实现数字信号和模拟信号的转换而达到控制的要求。-This paper discusses the application of the single chip microcomputer control system applied in switching power supply method and principle, put forward switching power supply adjustable voltage regulator output point of view. That can realize switching power supply control regulation, and through the analysis of the working principle of voltage, voltage regulation method, A/D chip and the principle, so that the output voltage to achieve 0.1 ~ 15V step regulator. Finally draw the conclusion that the DC switching power supply under the control of single-chip microcomputer can output stable, adjustable DC voltage to the conclusion.