【正文】 攀枝花學(xué)院本科畢業(yè)設(shè)計(jì)（論文） 基于單片機(jī) 數(shù)控式直流 恒流 源 設(shè)計(jì) 學(xué)生姓名： 學(xué)生學(xué)號(hào)： 202110501020 院（系 ）： 電 氣信 息 工程 學(xué)院 年級(jí)專業(yè)： 2021 級(jí) 電 子信息工程 指導(dǎo)教師： 劉衍平 (助教 /碩士 ) 二 〇一一年 六月 摘 要 I 摘 要 一般地，將輸出恒定的電流源稱為恒流源， “ 恒流源 ” 這個(gè)術(shù)語，原則上是指這樣一種穩(wěn)定電源：它輸出的電流與外部影響無關(guān) 即和負(fù)載改變大小無關(guān) 。實(shí)際上，大多數(shù)恒流源是用電子 電路實(shí)現(xiàn)的，而且僅當(dāng)外部條件在一定的范圍內(nèi)變化時(shí)才能保持輸出電流基本不變。 本系統(tǒng)以直流電流源為核心， AT89S52 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(jí)可達(dá) 1mA，并可由 LCD1602 顯示 電流設(shè)定值和實(shí)際輸出電流值。本系統(tǒng)由單片機(jī)程控設(shè)定數(shù)字信號(hào)，經(jīng)過 D/A 轉(zhuǎn)換器（ TLC5615）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。單片機(jī)系統(tǒng)還兼顧對(duì)恒流源進(jìn)行實(shí)時(shí)監(jiān)控，輸出電流經(jīng)過電流 /電壓轉(zhuǎn)換后，通過 A/D 轉(zhuǎn)換芯片 (TLC2543)，實(shí)時(shí)把模擬量轉(zhuǎn)化為數(shù)據(jù)量，再經(jīng)單片機(jī)分析處理，通過數(shù)字量形式的反饋環(huán)節(jié)，使電流更加穩(wěn)定，這樣構(gòu)成穩(wěn)定的壓控電流源。實(shí)際測試結(jié)果表明，本系統(tǒng)能有效應(yīng)用于需要高穩(wěn)定度的小功率恒流源的領(lǐng)域。 關(guān)鍵字 數(shù)控直流恒流源 ， 單片機(jī) ， D/A 轉(zhuǎn)換器 ， A/D 轉(zhuǎn)換 ，電壓 /電流轉(zhuǎn)換器 攀枝花學(xué)院本科畢業(yè)設(shè)計(jì) (論文 ) II ABSTRACT In this system the DC source is center and 89S52 version single chip microputer (SCM) is main controller, output current of DC power can be set by a keyboard which step level reaches 1mA, while the real output current and the set value can be displayed by LCD. In the system, the digitally programmable signal from SCM is converted to analog value by DAC (TLV5616), then the analog value which is isolated and amplified by operational amplifiers, is sent to the base electrode of power transistor, so an adjustable output current can be available with the base electrode voltage of power transistor. Using the keyboard to set the needed output current value, The SCM based on some specific algorithm to deal the certain settings for processing. Corresponding voltage output by the ADC output voltagecontrolled current source the other hand, The constant current source can be monitored by the SCM system realtimely, its work process is that output current is converted voltage, then its analog value is converted to digital value by ADC, finally the digital value as a feedback loop is processed by SCM so that output current is more stable, so a stable voltagecontrolled constant current power is designed. The test results have showed that this system, pared with the traditional regulated current source, has easy to operate and features high output current stability. Key words: Numerical control dc constantcurrent source， microcontroller， D/A converter， A/D conversion 目 錄 I 目 錄 摘 要 ........................................................................................................................................... I ABSTRACT ...................................................................................................................................... II 目 錄 ..............................................................................................................................................I 1 緒 論 ......................................................................................................................................... 1 2 數(shù)控直流恒流源系統(tǒng)描述 ....................................................................................................... 2 系統(tǒng)簡介 ................................................................................................................................. 2 系統(tǒng)總體設(shè)計(jì) .......................................................................................................................... 3 方案論證 ................................................................................................................................. 3 主控器 ........................................................................................................................... 3 供電電源 ........................................................................................................................ 3 恒流源 ........................................................................................................................... 4 DAC和 ADC方案論證 ....................................................................................................... 5 鍵盤 ............................................................................................................................... 6 顯示 ............................................................................................................................... 6 3 系統(tǒng)硬件設(shè)計(jì) ........................................................................................................................... 8 主控電路設(shè)計(jì) .......................................................................................................................... 8 供電電源設(shè)計(jì) ......................................................................................................................... 9 主電源 ........................................................................................................................... 9 單片機(jī)電源（第二級(jí)電源） .......................................................................................... 10 電源參數(shù)計(jì)算 [10] ........................................................................................................... 10 恒流源電路設(shè)計(jì) ..................................................................................................................... 12 D/A 轉(zhuǎn)換電路設(shè)計(jì) .................................................................................................................. 12 D/A和 A/D轉(zhuǎn)換器介紹 [12]............................................................................................. 12 理論分析與參數(shù)計(jì)算 [12] ................................................................................................. 16 測電路設(shè)計(jì) ............................................................................................................................ 16 [2] .....................................................................................