【正文】 which can be set liberally in 1mA~2020mA, so it can be applied in need areas of constant current source with high stability and low power. Key words: High accuracy； DAC0832； D/A converter； Constant； current resourc 目 錄 東 華理工大學(xué)長江學(xué)院畢業(yè)設(shè)計 (論文 ) 目錄 1 緒論 ........................................................................................................................... 1 電流源簡介 ............................................................................................................. 1 數(shù)控電流源的必要性 ............................................................................................. 1 數(shù)控電流源的可行性 ............................................................................................ 1 2 系統(tǒng)總體方案設(shè)計與論證 ..................................................................................... 2 設(shè)計任務(wù)及要求 ..................................................................................................... 2 傳統(tǒng)直流電流源的設(shè)計方案 ................................................................................. 2 數(shù)控直流電流源方案 ............................................................................................ 3 數(shù)控直流電流源的比較方案 ................................................................................. 3 本系統(tǒng)的特點(diǎn) ......................................................................................................... 4 3 數(shù)控直流電流源硬件設(shè)計 ..................................................................................... 5 芯片 AT89C52 簡介 ................................................................................................ 5 AT89C52 主要功能特性 .................................................................................. 5 AT89C52 管腳說明 .......................................................................................... 5 AT89C52 對編程操作提供的編程方法 .......................................................... 7 數(shù)控直流電流源的總機(jī)電路原理 ......................................................................... 7 4 數(shù)控電流源的軟件系統(tǒng)設(shè)計 ................................................................................. 9 各模塊程序流程圖 ................................................................................................. 9 總程序流程圖 .................................................................................................. 9 設(shè)置輸出電流給定值程序流程圖 ................................................................ 11 設(shè)置電流步進(jìn)值程序流程圖 ........................................................................ 11 鍵盤掃描程序流程圖 .................................................................................... 12 源程序 .................................................................................................................. 15 結(jié)論 ............................................................................................................................. 25 致謝 ............................................................................................................................. 26 參考文獻(xiàn) ..................................................................................................................... 27 1 緒 論 東華理工大學(xué)長江學(xué)院畢業(yè)設(shè)計 (論文 ) 緒論 2 電流源簡介 所謂恒流源就是輸出電流極其穩(wěn)定不隨負(fù)載變化。 關(guān)鍵詞 ： 高精度； DAC0832； D/A 轉(zhuǎn)換；恒流源； 軟件修正 ABSTRACT 東華理工大學(xué)長江學(xué)院畢業(yè)設(shè)計 (論文 ) ABSTRACT Along with single slice machine technical of develop continuously with the D/A, the A/D is technical continuously the maturity make the number control power supply to make possible, count to control the electric current source and is control accuracy in spite of still on the maneuverability all there is traditional power supply can39。實(shí)際測試結(jié)果表明，本系統(tǒng)輸出電流穩(wěn)定，不隨負(fù)載和環(huán)境溫度變化，并具有很高的精度，輸出電流誤差范圍177。 系統(tǒng)以直流電流源為核心，AT89C52 單片機(jī)為主控制器，通過鍵盤來設(shè)置直流電源的輸出電流，設(shè)置步進(jìn)等級可達(dá) 1mA，并可由數(shù)碼管顯示電流設(shè)定值。 東華理工大學(xué)長江學(xué)院 畢業(yè)設(shè)計（論文 ） 中 文 題： 數(shù)控直流電流源 英 文 題： The Digital Controlled Direct Current Source 二零零九年六月 東華理工大學(xué)長江學(xué)院畢業(yè)設(shè)計 (論文 ) 扉頁 EAST CHINA INSTITUTE OF TECHNOLOGY CHANGJIANG INSTITUTE GRADUATION PROJECT (PAPER) TITLE: The Digital Controlled Direct Current Source SPECIALIZED: Electronic and Information Engineering CLASS AND GRADE: 053141 STUDENT NUMBER: 05314111 STUDENT NAME: JIAO LING FANG INSTRUCTS TEACHER: GAO LANG QIN DATE:20206 摘 要 東華理工大學(xué)長江學(xué)院畢業(yè)設(shè)計 (論文 ) 摘要 隨著 單片機(jī)技術(shù)的不斷發(fā)展和 D/A， A/D 技術(shù)的不斷成熟使得數(shù)控電源成為可能， 數(shù)控 電流源不論是在控制精度還是在可操作性上都有傳統(tǒng)電源無法比擬的優(yōu)勢。 本文在參考傳 統(tǒng)電流源以及普通數(shù)控電流源的基礎(chǔ)上，在充分考慮性價比的同時極大地 提高了數(shù)控電流源的準(zhǔn)確性， 通過 軟件修正以后在使用普通元件的情況下 數(shù)控 電流源的 性 能也達(dá)到了比較高的水平 。本系統(tǒng)由單片機(jī)程控輸出數(shù)字信號，經(jīng) 過 D/A 轉(zhuǎn)換器（ DA0832）輸出模擬量，再經(jīng)過運(yùn)算放大器隔離放大，控制輸出功率管的基極，隨著功率管基極電壓的變化而輸出不同的電流。 5mA，輸出電流可在 1mA~2020mA 范圍內(nèi)任意設(shè)定，因而可實(shí)際應(yīng)用于需要高穩(wěn)定度小功率恒流源的領(lǐng)域 。t pare to of advantage. This text in making reference to the foundation that the traditional electric current source and mon number control the electric current source, at the full consideration price pare of in the meantime raised a number to control the accuracy of the electric current source biggest, pass the software correction hereafter while use the circumstance of the mon ponent the number controls the electric current source of the function also es to a higher level. For the system that DC source is center and 89C52 version single chip microputer (SCM) is main controller, output current of DC power can be set by a keyboard which step level of 1mA can be available, while the real output current and set value can be displayed by LED. In the system, the digita