【正文】 ....... 8 3. 數(shù)控電流源硬件模塊設(shè)計(jì) ............................................................................................... 9 . 電源模塊 ........................................................................................................ 9 . 電源原理 ................................................................................................. 9 . 電源方案確定 ......................................................................................... 10 . 電源模塊具體電路 .................................................................................. 10 . 電源模塊 PCB設(shè)計(jì) .................................................................................11 . 顯示模塊 ................................................................................................11 . D/A電路 ....................................................................................................... 12 . DAC0832簡(jiǎn)介 ....................................................................................... 12 . 具體電路設(shè)計(jì) ......................................................................................... 14 . 控制電壓產(chǎn)生電路 .................................................................................. 15 . 電流輸出模塊 ................................................................................................ 15 . 具體電路圖 ............................................................................................ 17 . 主控部分 ...................................................................................................... 18 . AT89C52單片機(jī)系統(tǒng)及外圍電路 ............................................................. 18 . 單片機(jī)時(shí)鐘脈沖電路 .............................................................................. 18 . 復(fù)位電路 ............................................................................................... 18 . 主控部分具體電路 .................................................................................. 19 IV 4. 數(shù)控電流源的軟件系統(tǒng)設(shè)計(jì) ......................................................................................... 20 . 具體模塊劃分 ................................................................................................ 20 . 數(shù)值處理 ...................................................................................................... 21 5. 系統(tǒng)測(cè)試 .................................................................................................................... 22 . 設(shè)計(jì)創(chuàng)新點(diǎn) ................................................................................................... 22 . 系統(tǒng)性能檢測(cè) ................................................................................................ 22 . 減小紋波所采用的措施 ........................................................................... 23 . 紋波電流測(cè)試 ......................................................................................... 23 . 誤差分析 ...................................................................................................... 24 6. 結(jié)論 ........................................................................................................................... 25 致謝 ......................................................................................................... 錯(cuò)誤 !未定義書簽。 關(guān)鍵字： 高精度； D/A 轉(zhuǎn)換； 電流源； 軟件修正 II DC Current Source Design NC Abstract: Often used in electronic equipment in good stability, high accuracy, output preset dc current source. Progress unremittingly the request to the electronics instrument technically to also raise continuously along with the electronics, the power supply is the motive source of the electric circuit to play a more and more important role more, is the school a laboratory still repair centerses to all can not get away from an experiment power supply in spite of, however the traditional power supply is control accuracy or output the tops of the characteristic in spite of and can39。 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(shì)。電源作為電路的動(dòng)力源泉更是扮演著越來越重要的角色，不論是學(xué)校實(shí)驗(yàn)室還是維修中心都離不開實(shí)驗(yàn)電流源，然而傳統(tǒng)的電流源不論是在控制精度還是輸出特性上都無法滿足要求。 I 摘 要 在電子設(shè)備中經(jīng)常用到穩(wěn)定性好、精度高、輸出可預(yù)置的直流電流源。 隨著電子技術(shù)的不斷進(jìn)步，對(duì)電子儀器的要求也不斷提高。 該電流源具有設(shè)定準(zhǔn)確、輸出電流穩(wěn)定、可調(diào)范圍全程線性等特點(diǎn)。 此設(shè)計(jì)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(jià)比的同時(shí)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 。t satisfy a request. This direct current source not only can steadily output, but also can be accurately initialized, and adjusted linearly at a wide 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。 參考文獻(xiàn) ........................................................................................................................... 27 附錄 1................................................................................................................................ 28 附錄 2................................................................................................................................ 41 畢業(yè)設(shè)計(jì)（論文）紙 共 41 頁 第 5 頁 ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ 裝 ┊ ┊ ┊ ┊ ┊ 訂 ┊ ┊ ┊ ┊ ┊ 線 ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ 1. 緒論 . 電流源簡(jiǎn)介 所謂恒 流 源就是輸出 電流 極其穩(wěn)定不隨負(fù)載變化。即負(fù)載需要多大電壓，恒流源就 必須輸出多大電壓， “無條件 ”予以滿足。如果 R→∞ ，那么 V→∞ 。對(duì)于實(shí)際電路，當(dāng) R 大到一定程度，電壓輸出能力就會(huì)不夠，輸出電流必然下降，不再恒定。通過時(shí)刻 “檢查 ”控制對(duì)象的狀態(tài)，并進(jìn)行調(diào)整。形象地說， 電流 負(fù) 反饋電路則是采樣輸出電流，計(jì)算誤差，據(jù)此調(diào)節(jié)自身狀態(tài)，使輸出電流穩(wěn)定，因而，輸出特性接近恒流源。一 般希望Ro→∞ 。 隨著電子技術(shù)的不斷進(jìn)步對(duì)電子儀器的要求不斷提高，電源作為電路的動(dòng)力源泉更是扮演著越來越重要的角色，不論是學(xué)校實(shí)驗(yàn)室還是維修中心都離不開實(shí)驗(yàn)電源，然而傳統(tǒng)的電源不論是在控制精度還是輸出特性上都無法滿足要求。從可操作性來看傳統(tǒng)電流原電位器上的刻度有限，不可能非常精細(xì)，僅僅靠電位器的幾個(gè)刻度對(duì)操作者的技巧要求比較高，同時(shí)誤差也比較大。 . 數(shù)控電流源技術(shù)的發(fā)展 由于單片機(jī)技術(shù)的不斷發(fā)展和 D/A， A/D 元件的普