【正文】 voltage. Otherwise, the output current can be monitored by the MCU realtimely. The currenttovoltage conversion is pleted when the current pass through the sampling resistor whose thermal stability is very well. At the same time, the DAC is achieved by the TLC0832 after the phase amplification of the voltage on sampling resistor. And then the MCU will analyse and process the data. The output current can be more stable by the feedback loop so that a stable voltagecontrolled constant current power is designed. Keywords： P89V51； DAC0832； TLC0832； TIP122； Constant current power III 目 錄 第一章 緒論 ...................................................................................................................................... 1 電流源簡介 .......................................................................................................................... 1 問題提出 .............................................................................................................................. 1 歷史發(fā)展及趨向預(yù)測 ............................................................................................................ 1 歷史發(fā)展 ....................................................................................................................... 1 趨向預(yù)測 ....................................................................................................................... 1 數(shù)控直流電流源的可行性 ..................................................................................................... 2 研究方向 .............................................................................................................................. 2 工作內(nèi)容 .............................................................................................................................. 2 第二章 總體方案論證與比較 ............................................................................................................. 3 傳統(tǒng)電流源的設(shè)計(jì)方案 ......................................................................................................... 3 數(shù)控直流電流源 ................................................................................................................... 3 數(shù)控直流電流源的方案論證與比較 ....................................................................................... 4 第三章 模塊硬件電路的設(shè)計(jì)與比較 ................................................................................................... 5 單片機(jī) P89V51 芯片的介紹 .................................................................................................. 5 P89V51 單片機(jī)的性能介紹 .............................................................................................. 5 功能引腳說明 ................................................................................................................ 5 數(shù)模轉(zhuǎn)換模塊 ....................................................................................................................... 7 DAC0832 概述 ................................................................................................................ 7 DAC0832 參考電壓的選擇 ............................................................................................... 9 數(shù)模轉(zhuǎn)換模塊設(shè)計(jì)方案 .................................................................................................. 9 模數(shù)芯片 TLC0832 概述 ....................................................................................................... 9 人機(jī)界面方案的選擇 ...........................................................................................................10 恒流源方案的選擇 ...............................................................................................................12 反饋 閉環(huán)方案的選擇 ...........................................................................................................12 閉環(huán)系統(tǒng)的原理 ............................................................................................................12 數(shù)控直流電流源閉環(huán)系統(tǒng)方案選擇 ................................................................................13 電源方案的選擇 ..................................................................................................................14 各電源模塊的設(shè)計(jì) ........................................................................................................14 三端集成穩(wěn)壓器概述 .....................................................................................................15 系統(tǒng)電源模塊的抗干擾措施 ..........................................................................................15 第四章 軟件設(shè)計(jì) ..............................................................................................................................16 主程序模塊 MAIN ...............................................................................................................16 定時(shí)器中斷服務(wù)子程序 ........................................................................................................16 鍵盤掃描子程序模塊 ...........................................................................................................16 第五章 數(shù)據(jù)測試及分析 ...................................................................................................................19 空載輸出電流測試和步進(jìn)測試 ................................................................