摘要：數控直流穩壓電源就是能用數字來控制電源輸出電壓的大小，而且是能使輸出的直流電壓保持穩定、精確的直流電壓源。本文采用AT89C51單片機與橋式整流電路及三端集成穩壓器實現對直流穩壓電源的數字化控制。電路由數字控制部分、D／A轉換部分、可調穩壓部分組成。通過改變輸入數字量來改變輸出電壓值(A／D轉換后電壓值)，經集成運放放大和射極輸出器輸出，間接地改變輸出電壓的大小。數字控制部分采用+，-按鍵來調整控制電壓值，二進制計數器輸出輸入到D／A轉換器中，經過D／A轉換后，控制調整步進為0.1V，經測試，可輸出0～12V的穩定直流電源，輸出電壓采用LED共陰極數碼顯示。該系統具有通用性好、可靠性高、線路簡單、成本低廉、使用方便的優點。

關鍵詞：AT89C51；轉換；數控；電壓源；橋式整流

Abstract:Numerical-controlled dc voltage source is the source that can control the output voltage, make the output voltage remain stable and precise. We can use AT89C51 microcontroller, bridge rectifier circuit and three integrated stabilizer to realize the digital control of dc voltage. Electric circuit is made up by digital control circuits, D/A transformation and adjustable voltage. Output voltage can be changed by input digital quantity (voltage value after A/D conversion). The output voltage can be indirectly changed by the integrated operational and output shot. Digital control adopts buttons +,- to adjust and control voltage value. Binary counter output and input value to D/A converter. Set the step of adjustment with 0.1V after D/A transformation. By test, it can supply stable dc power of 0 ~ 12 V. The output voltage of cathode displays by LED digital. The system has a series of advantages, such as excellent versatility,high reliabilitysimple line,low cost,and easy to use.

Keywords: AT89C51;Transformation; Numerical control; Voltage source; Bridge rectifier