在控制单元的开关调整元件（T1）接通期间，能量流进贮能单元（C12）进行储能，当开关调整元件关断时，存储在电容里的能量通过滤波直接给负载供电，取样电路对输出电压进行取样，反馈到运放比较的输入端，运放电路将取样电压与PWM输出电压进行比较，比较之后输出一定脉宽给控制单元，控制开关调整元件的导通时间，从而控制储能输出，使输出值与预设值相等，减小误差。同时，通过取样电路对输出取样，送至单片机，经过内部模数转换，按键切换时，LED便可显示实际输出值-The switch in control unit (T1) through adjusting devices, during the energy flow into storage unit (can), storage, when the C12 cut-off switches adjust components, the energy stored in the capacitance by filtering directly to load power, sampling circuit of sampling, the output voltage feedback amp compared to the input, amp circuit will sample PWM voltage output voltage and comparison, after comparing output pulse-width must give the control unit, adjusting control switch conduction time of components, and control energy output, the output value and preset equal, reduce the error. At the same time, through sampling circuit for output samples, and sent to the microcontroller, internal key switch to digital converter, can show the actual, LED the output value