【正文】 宜春學(xué)院物理科學(xué)與工程技術(shù)學(xué)院畢業(yè)設(shè)計 I 基于數(shù)控直流電流源系統(tǒng)的設(shè)計 宜春學(xué)院 物理科學(xué)與工程技術(shù)學(xué)院 電子信息科學(xué)與技術(shù)專業(yè) 李偉 指導(dǎo)老師：胡振平 摘要： 隨著電子技術(shù)的發(fā)展、數(shù)字電路應(yīng)用領(lǐng)域的擴展，人們對數(shù)控恒定電流器件的需求越來越高。應(yīng)社會發(fā)展的需求， 對基于單片機控制的“數(shù)控 直流電流源的設(shè)計 ”進行研究論證，并運用 Proteus軟件進行仿真。 以直流穩(wěn)壓電源和穩(wěn)流電源為核心，結(jié)合單片機最小系統(tǒng)實現(xiàn)對輸出電流的控制。首先采用了單片集成穩(wěn)壓芯片實現(xiàn)直流穩(wěn)壓，然后采用了分立元件實現(xiàn)穩(wěn)流。為實現(xiàn)對輸出電流的精確控制：一方面，通過Ｄ ／Ａ輸出實現(xiàn)電流的預(yù)置，再通過運算放大器控制晶體管的輸出電流；另一方面，運用Ａ／Ｄ轉(zhuǎn)換器件將輸出電流的采樣值送入單片機，與預(yù)置值進行比較，將誤差值通過Ｄ／Ａ轉(zhuǎn)換芯片添加到調(diào)整電路，從而進一步降低了輸出電流的紋波 。 Abstract： The requiements of numerical controlling constant current devices is increasing as development of electronic technology and expanding of digital circuit applicational field. As to satisfy society development, do a study based on Numerical control dc current source design of SCM controlling and apply Proteus to simulating （ digital current ） Voltage regulator and DC current regulator is the key part of the design， its output current is controlled by single chip microprocessor,Firstly,single chip IC（ integrated circuit） Voltage regulator LM338K is used to generate stable voltage, and then desperate devices is used to generate stabilize current . Tocontrol the output current ， on one hand ,system sets output current by D/A（ digital／ analogue converter and controls current of transistor by operational amplifier ； on the other hand ， with the help of A/D（ analogue／ digital） converter， system samples the output current and convert it into digital data ， pares it with preset value ， converts the error value into analogy and puts it on adjusting circuit ， and decreases the ripple of the system output current ． 宜春學(xué)院物理科學(xué)與工程技術(shù)學(xué)院畢業(yè)設(shè)計 II 目錄 1 引言 ..........................................................................................................................................1 數(shù)控直流電流源的發(fā)展現(xiàn)狀 ............................................................................................1 數(shù)控直流電流源的研究意義 ............................................................................................1 該研究解決的主要內(nèi)容 ...................................................................................................1 2 設(shè)計任務(wù)及要求 .......................................................................................................................1 任務(wù) ..................................................................................................................................1 設(shè)計思路 ..........................................................................................................................2 方案論證 ..........................................................................................................................2 總體方案設(shè)計 ...................................................................................................................2 3 硬件系統(tǒng)的設(shè)計 .......................................................................................................................3 硬件系統(tǒng)的模塊 .............................................................................................................3 單片機最小系統(tǒng) ....................................................................................................3 自制電源模塊 .......................................................................................................5 顯示模塊 ..............................................................................................................5 鍵盤模塊 ..............................................................................................................7 電流源模塊 ...........................................................................................................8 負載模塊 ..............................................................................................................8 D/A、 A/D 轉(zhuǎn)換模塊 ..............................................................................................8 系統(tǒng)的原理圖 .................................................................................................................9 4 軟件系統(tǒng)的設(shè)計 ..................................................................................................................... 10 單片機資源使用情況 .................................................................................................... 10 軟件系統(tǒng)的模塊 ........................................................................................................... 10 程 序流程圖 .................................................................................................................. 11 程序清單 ...................................................................................................................... 15 5 仿真測試及結(jié)果 ..................................................................................................................... 15 設(shè)計結(jié)論及使用方法 .................................................................................................... 15 仿真結(jié)果 ...................................................................................................................... 15 輸出電流范圍仿真 .............................................................................................. 15 步進調(diào)整仿真 ..................................................................................................... 17 輸出電流仿真 ..................................................................................................... 17 誤差分析 ...................................................................................................................... 18 6 總結(jié) ........................................................................................................................................ 20 參考文獻 ..................................................................................................................................... 21 謝辭 ............................................................................................................................................ 22 附 錄 .........................