簡介(jie)直(zhi)流穩壓電(dian)源電(dian)路(lu)圖的3種設計方法(fa)

（1）晶(jing)體管串聯式直流穩壓(ya)(ya)(ya)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)框圖如圖1所示，該(gai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)中，輸(shu)出(chu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)UO經取(qu)樣(yang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)取(qu)樣(yang)后得到取(qu)樣(yang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)，取(qu)樣(yang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)與基準(zhun)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)進行(xing)比(bi)較得到誤(wu)差(cha)(cha)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)，該(gai)誤(wu)差(cha)(cha)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)對調整管的(de)工作(zuo)狀態進行(xing)調整，從(cong)而使輸(shu)出(chu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)發生(sheng)變(bian)化，該(gai)變(bian)化與由(you)于供(gong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)UI發生(sheng)變(bian)化引起的(de)輸(shu)出(chu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)的(de)變(bian)化正好相反，從(cong)而保證輸(shu)出(chu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)UO為恒定值（穩壓(ya)(ya)(ya)值）。

單純(chun)的(de)串聯式直(zhi)流穩壓電(dian)源電(dian)路(lu)(lu)很簡(jian)單，但增(zeng)加輔助電(dian)源后，電(dian)路(lu)(lu)比較復雜，由于都采用分立(li)元件(jian)，電(dian)路(lu)(lu)的(de)可(ke)靠(kao)性難以(yi)保證(zheng)。

（2）采用(yong)三端集(ji)成穩壓(ya)器電(dian)(dian)路。他采用(yong)輸(shu)(shu)出(chu)電(dian)(dian)壓(ya)可(ke)調(diao)且內(nei)部有(you)過載保護的(de)三端集(ji)成穩壓(ya)器，輸(shu)(shu)出(chu)電(dian)(dian)壓(ya)調(diao)整范圍較寬，設計一(yi)電(dian)(dian)壓(ya)補(bu)償電(dian)(dian)路可(ke)實現輸(shu)(shu)出(chu)電(dian)(dian)壓(ya)從0 V起連續可(ke)調(diao)。

（3）用單片(pian)(pian)機制作的(de)(de)可(ke)調(diao)直流(liu)穩壓(ya)電(dian)源(yuan)。該(gai)電(dian)路(lu)采(cai)用可(ke)控硅作為(wei)第一級(ji)(ji)調(diao)壓(ya)元件，用穩壓(ya)電(dian)源(yuan)芯(xin)片(pian)(pian)LM317，LM337作為(wei)第二級(ji)(ji)調(diao)壓(ya)元件，通過AT89CS51單片(pian)(pian)機控制繼電(dian)器改變(bian)電(dian)阻(zu)網絡的(de)(de)阻(zu)值，從而(er)改變(bian)調(diao)壓(ya)元件的(de)(de)外圍參數，并(bing)加上軟啟動(dong)電(dian)路(lu)，獲得0～24 V，0.1 V步長，驅動(dong)能力(li)可(ke)達(da)1 A，同(tong)時可(ke)以(yi)顯示電(dian)源(yuan)電(dian)壓(ya)值和輸出電(dian)流(liu)值的(de)(de)大小。

其硬件電(dian)(dian)(dian)路主要(yao)包括變壓(ya)(ya)(ya)器、整(zheng)流濾波電(dian)(dian)(dian)路、壓(ya)(ya)(ya)差控制電(dian)(dian)(dian)路、穩壓(ya)(ya)(ya)及輸(shu)出電(dian)(dian)(dian)壓(ya)(ya)(ya)控制電(dian)(dian)(dian)路、電(dian)(dian)(dian)壓(ya)(ya)(ya)電(dian)(dian)(dian)流采樣電(dian)(dian)(dian)路、掉(diao)電(dian)(dian)(dian)前重(zhong)要(yao)數據存儲電(dian)(dian)(dian)路、單片機(ji)、鍵盤顯示(shi)等幾部分，硬件部分原理圖如(ru)圖3所示(shi)。

正(zheng)、負端壓(ya)(ya)差控制(zhi)(zhi)電(dian)(dian)(dian)路(lu)(lu)的作用是減少LM317和LM337輸(shu)入端和輸(shu)出(chu)(chu)端的壓(ya)(ya)差以降低(di)LM317和LM337的功耗。穩壓(ya)(ya)電(dian)(dian)(dian)路(lu)(lu)由三端穩壓(ya)(ya)芯片(pian)LM317（負壓(ya)(ya)用LM337）及(ji)外圍(wei)器件組成，輸(shu)出(chu)(chu)電(dian)(dian)(dian)壓(ya)(ya)控制(zhi)(zhi)電(dian)(dian)(dian)路(lu)(lu)采(cai)用繼電(dian)(dian)(dian)器控制(zhi)(zhi)的電(dian)(dian)(dian)阻網絡。

該(gai)電源(yuan)(yuan)穩(wen)定性(xing)好、精度(du)高(gao)，并(bing)且(qie)能(neng)夠輸出±24 V范圍(wei)內(nei)的可調直流(liu)電壓，且(qie)其(qi)性(xing)能(neng)優于(yu)(yu)傳統(tong)的可調直流(liu)穩(wen)壓電源(yuan)(yuan)，但是電路(lu)比較(jiao)復雜(za)，成(cheng)本較(jiao)高(gao)，使用于(yu)(yu)要求較(jiao)高(gao)的場(chang)合。在(zai)實(shi)際中(zhong)，如果對(dui)電路(lu)的要求不太高(gao)（這種情況較(jiao)多），多采(cai)用第二種設計(ji)方案(an)。