在進行電器電路模塊規劃或給新產品定型時，許多人(ren)不會去細心考慮配套(tao)開(kai)關(guan)電源(yuan)的選擇(ze)，直到(dao)發現(xian)開(kai)關(guan)電源(yuan)部分有了故障問題(ti)，才從頭(tou)處理(li)這個問題(ti)。

一、選擇開關(guan)電源的基本依據

電壓(ya)和電流(liu)規(gui)劃，這是兩個最容(rong)易承認的(de)目(mu)標，只需依據電路(lu)的(de)功耗計算出即可。也(ye)應考慮檢驗高、低供電電壓(ya)極值。

大多數固(gu)定電源答應輸(shu)出(chu)電壓±10%的規劃(hua)內(nei)改動，假設(she)這還不(bu)能滿(man)意電路要(yao)求(qiu)，可選(xuan)用輸(shu)出(chu)可調的或答應**改動規劃(hua)的電源。

假設用該(gai)電(dian)源給組合式設備供電(dian)，則設備所需**的(de)電(dian)流(liu)的(de)75%到90%由一(yi)個(ge)電(dian)源供應，不夠部分可并接兩個(ge)或更(geng)多電(dian)源。

二、開關電(dian)源的擴展(zhan)和安全性

1、并聯或串聯作業

當一(yi)個(ge)電(dian)(dian)(dian)源(yuan)(yuan)不能(neng)滿意所需的電(dian)(dian)(dian)壓或(huo)電(dian)(dian)(dian)流(liu)規劃時，可(ke)將兩(liang)個(ge)或(huo)多個(ge)電(dian)(dian)(dian)源(yuan)(yuan)(或(huo)將同(tong)一(yi)電(dian)(dian)(dian)源(yuan)(yuan)的不同(tong)輸出)并聯(lian)或(huo)串聯(lian)起(qi)來(lai)運(yun)用。在這(zhe)種作業方式下，各(ge)電(dian)(dian)(dian)源(yuan)(yuan)模塊(kuai)間的穩壓和(he)控制電(dian)(dian)(dian)路之(zhi)間的聯(lian)絡仍然存在，只不過一(yi)個(ge)電(dian)(dian)(dian)源(yuan)(yuan)作為(wei)主控方另一(yi)個(ge)電(dian)(dian)(dian)源(yuan)(yuan)作為(wei)受(shou)控方運(yun)用。

2、過載保護

因為(wei)一個電(dian)(dian)(dian)源(yuan)(yuan)要供應不(bu)同的(de)(de)電(dian)(dian)(dian)路(lu)運用，這些電(dian)(dian)(dian)路(lu)的(de)(de)電(dian)(dian)(dian)流的(de)(de)流量可能是不(bu)知道的(de)(de)，為(wei)了防止(zhi)對電(dian)(dian)(dian)源(yuan)(yuan)的(de)(de)損(sun)壞，需設置(zhi)保護電(dian)(dian)(dian)路(lu)的(de)(de)規劃。

簡直一切的(de)電(dian)(dian)源(yuan)(yuan)都具有以下特(te)征：在(zai)超(chao)(chao)出(chu)(chu)輸出(chu)(chu)規劃(hua)時，要(yao)(yao)么輸出(chu)(chu)保持在(zai)**輸出(chu)(chu)值(zhi)，要(yao)(yao)么就(jiu)自行(xing)封(feng)閉(bi)電(dian)(dian)源(yuan)(yuan)。某些(xie)程控電(dian)(dian)源(yuan)(yuan)除可(ke)用(yong)程序設(she)定輸出(chu)(chu)規劃(hua)外(wai)(wai)，還能主動設(she)置(zhi)電(dian)(dian)源(yuan)(yuan)安穩(wen)輸出(chu)(chu)的(de)類(lei)型。也(ye)就(jiu)是說，當外(wai)(wai)電(dian)(dian)路需(xu)求的(de)電(dian)(dian)壓(ya)或(huo)電(dian)(dian)流超(chao)(chao)越(yue)設(she)置(zhi)極(ji)限(xian)時，電(dian)(dian)源(yuan)(yuan)可(ke)主動地由恒壓(ya)源(yuan)(yuan)變(bian)成恒流源(yuan)(yuan)或(huo)由值(zhi)流源(yuan)(yuan)變(bian)成恒壓(ya)源(yuan)(yuan)。為電(dian)(dian)源(yuan)(yuan)加(jia)上保護二(er)極(ji)管能夠防(fang)止誤接外(wai)(wai)接電(dian)(dian)源(yuan)(yuan)的(de)極(ji)性構成的(de)損(sun)壞(huai)。熱傳感器也(ye)可(ke)用(yong)于防(fang)止由于電(dian)(dian)源(yuan)(yuan)繼續作業在(zai)過載狀態或(huo)冷卻無效而燒壞(huai)電(dian)(dian)源(yuan)(yuan)。

三、開(kai)關電源內部潛在的構成損(sun)害的根源

1、脈動與噪聲

志向的直流電(dian)(dian)源應(ying)供應(ying)純真(zhen)的直流，然而總(zong)有一些煩(fan)擾存在，比如在開關電(dian)(dian)源輸出端(duan)口疊加的脈動電(dian)(dian)流和高頻(pin)振動。這(zhe)兩種(zhong)煩(fan)擾再加上電(dian)(dian)源自身發生的尖峰(feng)噪聲使電(dian)(dian)源出現斷續和隨意的漂移。

2、安穩度

當(dang)線電(dian)壓或負載電(dian)流(liu)改動肘(zhou)，直流(liu)電(dian)源的輸出電(dian)壓也會有所(suo)高低(di)。穩壓程度由(you)穩壓電(dian)路的參數(shu)抉擇，參數(shu)是指濾波電(dian)容(rong)的容(rong)量和能量開釋的速率。

假設給電(dian)(dian)源供電(dian)(dian)的(de)(de)一個相對安穩的(de)(de)電(dian)(dian)源，那么只需基本的(de)(de)負載穩壓。安穩度的(de)(de)大(da)小一般(ban)定義(yi)為空(kong)載或滿載時(shi)輸出(chu)電(dian)(dian)壓的(de)(de)百分比，或電(dian)(dian)壓的(de)(de)改動(dong)值(zhi)。

3、內部阻抗

相對較大(da)的電(dian)(dian)(dian)源內(nei)阻對負載(zai)來講有兩點倒霉(mei)，首先是倒霉(mei)于負載(zai)穩壓電(dian)(dian)(dian)路作業，更為倒霉(mei)的是負載(zai)電(dian)(dian)(dian)流的任何改(gai)動(dong)都會導致直流電(dian)(dian)(dian)源輸出的高(gao)低，這種(zhong)高(gao)低對檢驗(yan)(yan)效(xiao)(xiao)果的影(ying)響(xiang)同(tong)脈沖與噪(zao)聲對檢驗(yan)(yan)效(xiao)(xiao)果構(gou)成的影(ying)響(xiang)完全相同(tong)。

4、開(kai)關電源瞬態呼應或恢復

電(dian)(dian)源瞬(shun)態呼應和(he)恢(hui)復(fu)(fu)(fu)時(shi)間的(de)大(da)小(xiao)標(biao)明輸(shu)出(chu)負(fu)載(zai)遽(ju)然(ran)改(gai)動(dong)時(shi)，電(dian)(dian)源穩壓(ya)電(dian)(dian)路恢(hui)復(fu)(fu)(fu)正(zheng)常電(dian)(dian)壓(ya)能力的(de)大(da)小(xiao)。有(you)兩種參數來標(biao)定(ding)電(dian)(dian)源瞬(shun)態呼應和(he)恢(hui)復(fu)(fu)(fu)：一(yi)是當負(fu)載(zai)遽(ju)然(ran)發生改(gai)動(dong)時(shi)輸(shu)出(chu)的(de)違(wei)反(fan)值(zhi)(zhi)；二是輸(shu)出(chu)恢(hui)復(fu)(fu)(fu)到原本(ben)值(zhi)(zhi)所用(yong)(yong)(yong)(yong)的(de)時(shi)間。為共同起見，一(yi)般(ban)在負(fu)載(zai)改(gai)動(dong)10%時(shi)，用(yong)(yong)(yong)(yong)輸(shu)出(chu)違(wei)反(fan)峰值(zhi)(zhi)電(dian)(dian)壓(ya)的(de)毫(hao)優數標(biao)定(ding)輸(shu)出(chu)違(wei)反(fan)量，用(yong)(yong)(yong)(yong)輸(shu)出(chu)恢(hui)復(fu)(fu)(fu)到正(zheng)常值(zhi)(zhi)所用(yong)(yong)(yong)(yong)毫(hao)伏數標(biao)定(ding)恢(hui)復(fu)(fu)(fu)時(shi)間。還有(you)一(yi)些生產廠商，用(yong)(yong)(yong)(yong)**的(de)負(fu)載(zai)電(dian)(dian)流(liu)改(gai)動(dong)測定(ding)恢(hui)復(fu)(fu)(fu)時(shi)間。比(bi)如用(yong)(yong)(yong)(yong)輸(shu)出(chu)電(dian)(dian)流(liu)改(gai)動(dong)的(de)50%到****時(shi)所用(yong)(yong)(yong)(yong)的(de)恢(hui)復(fu)(fu)(fu)正(zheng)常值(zhi)(zhi)的(de)時(shi)間。