開關電源不同于線性電源適配器，前者調整(zheng)管工(gong)作(zuo)在通、斷(duan)(duan)狀(zhuang)態(tai)，后者調整(zheng)管工(gong)作(zuo)在線性狀(zhuang)態(tai)。電(dian)源適(shi)(shi)(shi)(shi)配(pei)(pei)(pei)器(qi)通過控制調整(zheng)管的(de)通、斷(duan)(duan)時間實現穩壓。電(dian)源適(shi)(shi)(shi)(shi)配(pei)(pei)(pei)器(qi)的(de)優(you)點是體積小(xiao)、重量(liang)輕(qing)、功(gong)耗(hao)(hao)小(xiao)、穩壓范圍寬，效(xiao)率(lv)可高達80%～90%。調整(zheng)管功(gong)率(lv)損耗(hao)(hao)小(xiao)，散(san)熱器(qi)也(ye)隨之減小(xiao)。英規(gui)電(dian)源適(shi)(shi)(shi)(shi)配(pei)(pei)(pei)器(qi)工(gong)作(zuo)頻率(lv)在幾十千赫(he)茲甚至(zhi)幾百千赫(he)茲，濾波電(dian)感、電(dian)容元(yuan)件可用(yong)較小(xiao)的(de)容量(liang)，允許的(de)環境(jing)溫度也(ye)可以大大提高，廣泛應用(yong)在各種電(dian)子設備中(zhong)。本(ben)章主要(yao)介紹(shao)電(dian)源適(shi)(shi)(shi)(shi)配(pei)(pei)(pei)器(qi)的(de)基(ji)本(ben)構成、分(fen)類及工(gong)作(zuo)原理，讓讀者對電(dian)源適(shi)(shi)(shi)(shi)配(pei)(pei)(pei)器(qi)有(you)一個(ge)初(chu)步的(de)認識。

　　穩壓電源適配器的比較

　　電(dian)(dian)(dian)(dian)(dian)子(zi)設備離不(bu)開電(dian)(dian)(dian)(dian)(dian)源(yuan)適(shi)配(pei)(pei)器(qi)(qi)。電(dian)(dian)(dian)(dian)(dian)源(yuan)適(shi)配(pei)(pei)器(qi)(qi)供給電(dian)(dian)(dian)(dian)(dian)子(zi)設備所需要的(de)能(neng)(neng)量(liang)。電(dian)(dian)(dian)(dian)(dian)源(yuan)適(shi)配(pei)(pei)器(qi)(qi)的(de)性(xing)(xing)能(neng)(neng)、質量(liang)直(zhi)接(jie)影(ying)響著(zhu)電(dian)(dian)(dian)(dian)(dian)子(zi)設備的(de)安全可(ke)靠運行，故(gu)此(ci)對(dui)電(dian)(dian)(dian)(dian)(dian)子(zi)設備電(dian)(dian)(dian)(dian)(dian)源(yuan)適(shi)配(pei)(pei)器(qi)(qi)性(xing)(xing)能(neng)(neng)、質量(liang)的(de)要求也越來越高。現有(you)的(de)電(dian)(dian)(dian)(dian)(dian)源(yuan)適(shi)配(pei)(pei)器(qi)(qi)主要有(you)兩(liang)(liang)大類：串聯線性(xing)(xing)穩壓(ya)電(dian)(dian)(dian)(dian)(dian)源(yuan)適(shi)配(pei)(pei)器(qi)(qi)(簡稱線性(xing)(xing)電(dian)(dian)(dian)(dian)(dian)源(yuan)適(shi)配(pei)(pei)器(qi)(qi))和開關穩壓(ya)電(dian)(dian)(dian)(dian)(dian)源(yuan)適(shi)配(pei)(pei)器(qi)(qi)(簡稱電(dian)(dian)(dian)(dian)(dian)源(yuan)適(shi)配(pei)(pei)器(qi)(qi))。這兩(liang)(liang)類電(dian)(dian)(dian)(dian)(dian)源(yuan)適(shi)配(pei)(pei)器(qi)(qi)各具特(te)色而被廣泛應用。

　　線性電源適配器的結構與特點

　　線性電(dian)(dian)源適配器通常都是由電(dian)(dian)網所提(ti)供的(de)交流(liu)電(dian)(dian)，經過(guo)變(bian)壓、整流(liu)、濾(lv)波和穩壓環節而得到。其各個部分(fen)電(dian)(dian)路的(de)作用(yong)如下：

　　①電(dian)(dian)源(yuan)適配器(qi)變壓(ya)器(qi)——將220V電(dian)(dian)網電(dian)(dian)壓(ya)轉換為整流電(dian)(dian)路所需要的交(jiao)流電(dian)(dian)壓(ya)值，而(er)少部分電(dian)(dian)路采用電(dian)(dian)容降壓(ya)，如(ru)遙控電(dian)(dian)風(feng)扇電(dian)(dian)路。

　　②整(zheng)流(liu)(liu)電(dian)(dian)(dian)(dian)路(lu)(lu)——將(jiang)交(jiao)流(liu)(liu)電(dian)(dian)(dian)(dian)壓(ya)轉換為脈動直流(liu)(liu)電(dian)(dian)(dian)(dian)壓(ya)。常用的(de)整(zheng)流(liu)(liu)電(dian)(dian)(dian)(dian)路(lu)(lu)有半(ban)波整(zheng)流(liu)(liu)電(dian)(dian)(dian)(dian)路(lu)(lu)、全(quan)波整(zheng)流(liu)(liu)電(dian)(dian)(dian)(dian)路(lu)(lu)和橋式(shi)整(zheng)流(liu)(liu)電(dian)(dian)(dian)(dian)路(lu)(lu)。

　　③濾(lv)(lv)波(bo)(bo)(bo)電(dian)路——將(jiang)脈(mo)動直流(liu)電(dian)壓轉換(huan)成(cheng)較為平滑的(de)直流(liu)電(dian)壓。線性電(dian)源適(shi)配器中常用的(de)濾(lv)(lv)波(bo)(bo)(bo)電(dian)路有電(dian)感濾(lv)(lv)波(bo)(bo)(bo)、電(dian)容濾(lv)(lv)波(bo)(bo)(bo)和阻容濾(lv)(lv)波(bo)(bo)(bo)，其中最常用的(de)是(shi)電(dian)容濾(lv)(lv)波(bo)(bo)(bo)。

　　④穩壓電(dian)(dian)(dian)路(lu)——將直(zhi)流電(dian)(dian)(dian)源適配器的(de)(de)(de)輸出(chu)電(dian)(dian)(dian)壓穩定，基本(ben)不(bu)受電(dian)(dian)(dian)網電(dian)(dian)(dian)壓或負載的(de)(de)(de)影響(xiang)。在線性電(dian)(dian)(dian)源適配器中常用的(de)(de)(de)穩壓電(dian)(dian)(dian)路(lu)有(you)(you)二極管(guan)穩壓、串(chuan)聯(lian)穩壓。其(qi)中，串(chuan)聯(lian)穩壓有(you)(you)現成的(de)(de)(de)集成電(dian)(dian)(dian)路(lu)，如(ru)固(gu)定電(dian)(dian)(dian)壓輸出(chu)的(de)(de)(de)集成電(dian)(dian)(dian)路(lu)有(you)(you)LM78××，LM79××等，可(ke)調電(dian)(dian)(dian)壓輸出(chu)的(de)(de)(de)集成電(dian)(dian)(dian)路(lu)有(you)(you)LM317和LM337等。

　　4個功能模塊的線性穩壓電源適配器

　　線性電源(yuan)適配器(qi)的(de)優點(dian)是(shi)穩定性好、瞬態(tai)響應速度快、可靠(kao)性高、輸出電壓精度高和輸出紋波(bo)電壓小;缺(que)點(dian)是(shi)工(gong)(gong)作(zuo)(zuo)頻(pin)率(lv)低，所采用的(de)工(gong)(gong)頻(pin)變壓器(qi)、濾波(bo)器(qi)的(de)體積和重(zhong)量(liang)都(dou)較(jiao)大(da)。調整管工(gong)(gong)作(zuo)(zuo)在線性狀態(tai)，功耗(hao)大(da)、效(xiao)率(lv)低，需(xu)要加裝散熱器(qi)。