簡介直流穩壓電(dian)源電(dian)路(lu)圖(tu)的3種設計方法

（1）晶(jing)體管(guan)串聯式直流(liu)穩壓(ya)(ya)(ya)(ya)電(dian)(dian)路。電(dian)(dian)路框(kuang)圖如圖1所示，該(gai)電(dian)(dian)路中，輸出(chu)電(dian)(dian)壓(ya)(ya)(ya)(ya)UO經取(qu)樣(yang)電(dian)(dian)路取(qu)樣(yang)后得到(dao)(dao)取(qu)樣(yang)電(dian)(dian)壓(ya)(ya)(ya)(ya)，取(qu)樣(yang)電(dian)(dian)壓(ya)(ya)(ya)(ya)與基(ji)準電(dian)(dian)壓(ya)(ya)(ya)(ya)進(jin)行比較(jiao)得到(dao)(dao)誤差(cha)電(dian)(dian)壓(ya)(ya)(ya)(ya)，該(gai)誤差(cha)電(dian)(dian)壓(ya)(ya)(ya)(ya)對調(diao)整管(guan)的(de)工作狀態(tai)進(jin)行調(diao)整，從(cong)而使輸出(chu)電(dian)(dian)壓(ya)(ya)(ya)(ya)發(fa)生變(bian)(bian)(bian)化(hua)(hua)，該(gai)變(bian)(bian)(bian)化(hua)(hua)與由(you)于供電(dian)(dian)電(dian)(dian)壓(ya)(ya)(ya)(ya)UI發(fa)生變(bian)(bian)(bian)化(hua)(hua)引起的(de)輸出(chu)電(dian)(dian)壓(ya)(ya)(ya)(ya)的(de)變(bian)(bian)(bian)化(hua)(hua)正(zheng)好相反，從(cong)而保證輸出(chu)電(dian)(dian)壓(ya)(ya)(ya)(ya)UO為恒(heng)定值（穩壓(ya)(ya)(ya)(ya)值）。

單純的串(chuan)聯式直流穩(wen)壓電源電路(lu)(lu)很簡(jian)單，但(dan)增加輔助電源后，電路(lu)(lu)比較復(fu)雜，由于(yu)都采用分立元件，電路(lu)(lu)的可(ke)靠性難以(yi)保證。

（2）采用三(san)(san)端集(ji)成穩壓器電(dian)(dian)(dian)路。他(ta)采用輸(shu)(shu)出(chu)電(dian)(dian)(dian)壓可調且內部有過(guo)載(zai)保(bao)護的三(san)(san)端集(ji)成穩壓器，輸(shu)(shu)出(chu)電(dian)(dian)(dian)壓調整范圍較寬，設計一電(dian)(dian)(dian)壓補償電(dian)(dian)(dian)路可實(shi)現輸(shu)(shu)出(chu)電(dian)(dian)(dian)壓從0 V起連(lian)續可調。

（3）用單片機制作(zuo)的可(ke)調直流穩壓電(dian)(dian)(dian)源。該電(dian)(dian)(dian)路采用可(ke)控(kong)硅作(zuo)為第一級調壓元(yuan)件(jian)，用穩壓電(dian)(dian)(dian)源芯(xin)片LM317，LM337作(zuo)為第二級調壓元(yuan)件(jian)，通過AT89CS51單片機控(kong)制繼電(dian)(dian)(dian)器改變(bian)電(dian)(dian)(dian)阻(zu)網絡的阻(zu)值(zhi)，從而(er)改變(bian)調壓元(yuan)件(jian)的外(wai)圍參數，并加(jia)上軟啟動電(dian)(dian)(dian)路，獲得0～24 V，0.1 V步(bu)長(chang)，驅動能力(li)可(ke)達1 A，同時(shi)可(ke)以(yi)顯示電(dian)(dian)(dian)源電(dian)(dian)(dian)壓值(zhi)和輸出(chu)電(dian)(dian)(dian)流值(zhi)的大小。

其(qi)硬件(jian)(jian)電(dian)(dian)(dian)(dian)路(lu)主要包括(kuo)變壓器、整流濾(lv)波電(dian)(dian)(dian)(dian)路(lu)、壓差控制電(dian)(dian)(dian)(dian)路(lu)、穩(wen)壓及輸出電(dian)(dian)(dian)(dian)壓控制電(dian)(dian)(dian)(dian)路(lu)、電(dian)(dian)(dian)(dian)壓電(dian)(dian)(dian)(dian)流采(cai)樣電(dian)(dian)(dian)(dian)路(lu)、掉電(dian)(dian)(dian)(dian)前重要數(shu)據(ju)存儲電(dian)(dian)(dian)(dian)路(lu)、單片機、鍵盤(pan)顯示(shi)等幾部(bu)分，硬件(jian)(jian)部(bu)分原理圖如圖3所(suo)示(shi)。

正、負端(duan)壓差控制(zhi)電(dian)路的(de)作用(yong)是(shi)減少LM317和LM337輸入端(duan)和輸出(chu)端(duan)的(de)壓差以降低LM317和LM337的(de)功耗(hao)。穩壓電(dian)路由三(san)端(duan)穩壓芯片LM317（負壓用(yong)LM337）及外圍器件(jian)組成，輸出(chu)電(dian)壓控制(zhi)電(dian)路采(cai)用(yong)繼(ji)電(dian)器控制(zhi)的(de)電(dian)阻(zu)網絡。

該電(dian)(dian)(dian)源穩定性好、精度高(gao)，并且(qie)能夠(gou)輸(shu)出±24 V范圍內的(de)(de)可調直(zhi)流(liu)電(dian)(dian)(dian)壓(ya)，且(qie)其性能優(you)于傳統(tong)的(de)(de)可調直(zhi)流(liu)穩壓(ya)電(dian)(dian)(dian)源，但(dan)是電(dian)(dian)(dian)路比(bi)較(jiao)復雜，成本較(jiao)高(gao)，使(shi)用于要求較(jiao)高(gao)的(de)(de)場(chang)合(he)。在實際中(zhong)，如果(guo)對電(dian)(dian)(dian)路的(de)(de)要求不太高(gao)（這種(zhong)情(qing)況較(jiao)多(duo)），多(duo)采用第二種(zhong)設計方(fang)案。