簡介直(zhi)流穩壓電源電路圖的3種設計方法

（1）晶體管串聯(lian)式直(zhi)流穩壓(ya)(ya)電(dian)(dian)(dian)(dian)(dian)路。電(dian)(dian)(dian)(dian)(dian)路框圖(tu)如圖(tu)1所示，該電(dian)(dian)(dian)(dian)(dian)路中，輸出(chu)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)UO經取(qu)(qu)(qu)樣電(dian)(dian)(dian)(dian)(dian)路取(qu)(qu)(qu)樣后得到取(qu)(qu)(qu)樣電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)，取(qu)(qu)(qu)樣電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)與基準電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)進行比較得到誤(wu)差電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)，該誤(wu)差電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)對(dui)調整管的(de)(de)工作(zuo)狀態進行調整，從而使輸出(chu)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)發(fa)(fa)生變(bian)化(hua)，該變(bian)化(hua)與由于供電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)UI發(fa)(fa)生變(bian)化(hua)引起的(de)(de)輸出(chu)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)的(de)(de)變(bian)化(hua)正好相反，從而保證輸出(chu)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)UO為恒定值(zhi)（穩壓(ya)(ya)值(zhi)）。

單純的串聯式直流穩(wen)壓(ya)電(dian)(dian)(dian)源(yuan)電(dian)(dian)(dian)路很(hen)簡(jian)單，但增(zeng)加輔(fu)助(zhu)電(dian)(dian)(dian)源(yuan)后，電(dian)(dian)(dian)路比較復(fu)雜，由(you)于都采用分立元件，電(dian)(dian)(dian)路的可靠性難以(yi)保證。

（2）采(cai)用三端集(ji)成穩壓器電(dian)路(lu)。他采(cai)用輸(shu)(shu)出電(dian)壓可調(diao)且內部有過(guo)載保護的(de)三端集(ji)成穩壓器，輸(shu)(shu)出電(dian)壓調(diao)整范圍(wei)較寬，設計一電(dian)壓補(bu)償電(dian)路(lu)可實現輸(shu)(shu)出電(dian)壓從0 V起連續可調(diao)。

（3）用單片機(ji)制作(zuo)的(de)可調直流(liu)穩壓(ya)(ya)(ya)電(dian)(dian)源。該電(dian)(dian)路采用可控硅作(zuo)為第一級調壓(ya)(ya)(ya)元件，用穩壓(ya)(ya)(ya)電(dian)(dian)源芯片LM317，LM337作(zuo)為第二(er)級調壓(ya)(ya)(ya)元件，通過AT89CS51單片機(ji)控制繼(ji)電(dian)(dian)器改變(bian)電(dian)(dian)阻網絡的(de)阻值，從而(er)改變(bian)調壓(ya)(ya)(ya)元件的(de)外圍(wei)參(can)數，并加上軟(ruan)啟動(dong)電(dian)(dian)路，獲得(de)0～24 V，0.1 V步長，驅動(dong)能力可達1 A，同時可以(yi)顯示電(dian)(dian)源電(dian)(dian)壓(ya)(ya)(ya)值和輸出(chu)電(dian)(dian)流(liu)值的(de)大小。

其硬件(jian)電(dian)(dian)路(lu)主(zhu)要包括變壓(ya)(ya)器、整流濾波電(dian)(dian)路(lu)、壓(ya)(ya)差控(kong)制電(dian)(dian)路(lu)、穩壓(ya)(ya)及輸出電(dian)(dian)壓(ya)(ya)控(kong)制電(dian)(dian)路(lu)、電(dian)(dian)壓(ya)(ya)電(dian)(dian)流采樣電(dian)(dian)路(lu)、掉電(dian)(dian)前重要數據存儲電(dian)(dian)路(lu)、單片機、鍵(jian)盤顯示等(deng)幾部分，硬件(jian)部分原理圖如圖3所示。

正、負端(duan)壓(ya)(ya)差控(kong)制電(dian)路(lu)的(de)(de)作用(yong)是減少(shao)LM317和LM337輸(shu)入端(duan)和輸(shu)出端(duan)的(de)(de)壓(ya)(ya)差以降低LM317和LM337的(de)(de)功耗。穩壓(ya)(ya)電(dian)路(lu)由(you)三端(duan)穩壓(ya)(ya)芯片LM317（負壓(ya)(ya)用(yong)LM337）及外圍器件(jian)組成，輸(shu)出電(dian)壓(ya)(ya)控(kong)制電(dian)路(lu)采用(yong)繼電(dian)器控(kong)制的(de)(de)電(dian)阻(zu)網(wang)絡。

該電源穩(wen)定性(xing)好、精度(du)高，并且(qie)(qie)能夠輸(shu)出±24 V范圍內的(de)可(ke)(ke)調(diao)直(zhi)流(liu)電壓，且(qie)(qie)其性(xing)能優(you)于傳統的(de)可(ke)(ke)調(diao)直(zhi)流(liu)穩(wen)壓電源，但是電路(lu)比較(jiao)復雜，成本(ben)較(jiao)高，使用(yong)于要求較(jiao)高的(de)場合。在實(shi)際中(zhong)，如(ru)果(guo)對電路(lu)的(de)要求不(bu)太(tai)高（這種情況較(jiao)多(duo)），多(duo)采用(yong)第二(er)種設計方(fang)案(an)。