什么叫開關電源？

如今隨著電(dian)力電(dian)子(zi)技術的(de)開(kai)放(fang)和發(fa)展(zhan)創新，使得開(kai)關電(dian)源(yuan)技術也(ye)在不斷地(di)發(fa)展(zhan)。現在，開(kai)關電(dian)源(yuan)以小型、輕量和高(gao)功率的(de)特征被(bei)廣泛應用幾乎一切的(de)電(dian)子(zi)設備，是當今電(dian)子(zi)信息產業飛速(su)打開(kai)不行缺少的(de)一種電(dian)源(yuan)方案(an)。

開(kai)關電(dian)(dian)(dian)源(yuan)是運用(yong)現代(dai)電(dian)(dian)(dian)力(li)電(dian)(dian)(dian)子技術(shu)，操(cao)控(kong)開(kai)關管(guan)注冊和關斷的時(shi)刻比(bi)率，保持安(an)穩輸(shu)出(chu)電(dian)(dian)(dian)壓的一(yi)種(zhong)電(dian)(dian)(dian)源(yuan)，開(kai)關電(dian)(dian)(dian)源(yuan)一(yi)般由脈沖寬度調制(PWM)操(cao)控(kong)IC和MOSFET構(gou)成。

開(kai)(kai)關電(dian)源是相(xiang)對線性電(dian)源說的，其輸(shu)入端直接將交(jiao)流電(dian)整(zheng)流變成直流電(dian)，再在高頻(pin)(pin)震(zhen)動電(dian)路的效果(guo)下，用開(kai)(kai)關管操控電(dian)流的通斷(duan)，構成高頻(pin)(pin)脈(mo)沖電(dian)流。在電(dian)感(高頻(pin)(pin)變壓(ya)器)的幫助(zhu)下，輸(shu)出(chu)安穩的低壓(ya)直流電(dian)。

因為變壓(ya)器(qi)的(de)磁芯大(da)(da)小(xiao)與開(kai)關電(dian)源作業(ye)頻率(lv)(lv)的(de)平方(fang)成反(fan)比，頻率(lv)(lv)越高鐵心越小(xiao)。這(zhe)樣就能夠大(da)(da)大(da)(da)減小(xiao)變壓(ya)器(qi)，使電(dian)源減輕重量和體積。而且(qie)因為它直接操控直流(liu)，使這(zhe)種電(dian)源的(de)功率(lv)(lv)比線性電(dian)源高許多(duo)。這(zhe)樣就節省了動力(li)，因此它遭到(dao)人們的(de)喜(xi)愛。但它也有缺點(dian)，便是電(dian)路(lu)凌亂，修理(li)困難，對電(dian)路(lu)的(de)污染嚴峻。電(dian)源噪聲大(da)(da)，不適合(he)用于某些低噪聲電(dian)路(lu)。

開關電源的特征

開(kai)關(guan)(guan)電(dian)(dian)源一(yi)般由脈沖寬度調制(PWM)操控IC和(he)MOSFET構成。跟(gen)著(zhu)跟(gen)著(zhu)電(dian)(dian)力(li)電(dian)(dian)子技術(shu)的打開(kai)和(he)立異，現在(zai)開(kai)關(guan)(guan)電(dian)(dian)源首要(yao)(yao)以小(xiao)型(xing)、輕量和(he)高功(gong)率(lv)的特征被廣泛(fan)應(ying)用到幾(ji)乎一(yi)切的電(dian)(dian)子設備，其重要(yao)(yao)性(xing)可見(jian)一(yi)斑。

開關電源的分類

根據開(kai)關(guan)器材在電路中(zhong)連接的方案，開(kai)關(guan)電源總的來說可分為串聯式(shi)(shi)開(kai)關(guan)電源、并聯式(shi)(shi)開(kai)關(guan)電源、變壓器式(shi)(shi)開(kai)關(guan)電源等三大類。

其間，變(bian)壓(ya)(ya)器式(shi)(shi)(shi)(shi)開關電(dian)源(yuan)還能(neng)夠進(jin)一步(bu)分紅：推挽式(shi)(shi)(shi)(shi)、半橋(qiao)式(shi)(shi)(shi)(shi)、全橋(qiao)式(shi)(shi)(shi)(shi)等多種(zhong)。根據變(bian)壓(ya)(ya)器的鼓舞(wu)和(he)輸(shu)出(chu)電(dian)壓(ya)(ya)的相(xiang)位，又能(neng)夠分紅：正激(ji)式(shi)(shi)(shi)(shi)、反激(ji)式(shi)(shi)(shi)(shi)、單激(ji)式(shi)(shi)(shi)(shi)和(he)雙激(ji)式(shi)(shi)(shi)(shi)等多種(zhong)。

開關電源和一般電源的差異

一(yi)般的(de)電(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)一(yi)般是(shi)線(xian)性(xing)電(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)，線(xian)性(xing)電(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)，是(shi)指調(diao)整管(guan)作業(ye)在(zai)線(xian)性(xing)狀(zhuang)況(kuang)下的(de)電(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)。而在(zai)開(kai)關(guan)(guan)(guan)電(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)中則不相(xiang)同，開(kai)關(guan)(guan)(guan)管(guan)(在(zai)開(kai)關(guan)(guan)(guan)電(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)中，咱們一(yi)般把調(diao)整管(guan)叫(jiao)做開(kai)關(guan)(guan)(guan)管(guan))是(shi)作業(ye)在(zai)開(kai)、關(guan)(guan)(guan)兩種狀(zhuang)況(kuang)下的(de)：開(kai)——電(dian)(dian)(dian)阻(zu)很(hen)小，關(guan)(guan)(guan)——電(dian)(dian)(dian)阻(zu)很(hen)大。

開關電(dian)(dian)源(yuan)是一種比較(jiao)新(xin)式的電(dian)(dian)源(yuan)。它具有功率高(gao)，重(zhong)量輕，可升、降壓、輸出功率大等利益。但是因為電(dian)(dian)路作業在開關狀況，所以噪聲比較(jiao)大。

舉例(li)說(shuo)明：降(jiang)壓型開關電源

咱們來簡略的(de)說說降壓型(xing)開(kai)關(guan)電(dian)源的(de)作業原(yuan)理：電(dian)路由開(kai)關(guan)（實際(ji)電(dian)路中(zhong)為三極管或許場效應管），續(xu)流二極管、儲能(neng)電(dian)感、濾波電(dian)容等構成。

當(dang)開(kai)關(guan)閉(bi)合時(shi)，電(dian)(dian)(dian)(dian)源經(jing)過開(kai)關(guan)、電(dian)(dian)(dian)(dian)感(gan)(gan)給負載(zai)供電(dian)(dian)(dian)(dian)，并將部分電(dian)(dian)(dian)(dian)能儲存在(zai)電(dian)(dian)(dian)(dian)感(gan)(gan)以(yi)及電(dian)(dian)(dian)(dian)容中。因為(wei)電(dian)(dian)(dian)(dian)感(gan)(gan)的(de)自感(gan)(gan)，在(zai)開(kai)關(guan)接通(tong)后，電(dian)(dian)(dian)(dian)流增大得比(bi)較緩慢，即輸出不能馬上(shang)到達電(dian)(dian)(dian)(dian)源電(dian)(dian)(dian)(dian)壓值。

必定時(shi)刻(ke)后(hou)，開關斷開，因為電(dian)(dian)感(gan)(gan)的(de)自(zi)感(gan)(gan)效果（能(neng)夠比較形象的(de)認為電(dian)(dian)感(gan)(gan)中(zhong)的(de)電(dian)(dian)流(liu)有慣性效果），將堅持電(dian)(dian)路中(zhong)的(de)電(dian)(dian)流(liu)不變，即從左(zuo)往右(you)繼續(xu)流(liu)。這電(dian)(dian)流(liu)流(liu)過負(fu)載，從地線回(hui)來，流(liu)到續(xu)流(liu)二極(ji)管(guan)的(de)正極(ji)，經過二極(ji)管(guan)，回(hui)來電(dian)(dian)感(gan)(gan)的(de)左(zuo)端，然后(hou)構成了一(yi)個回(hui)路。

經(jing)過(guo)操(cao)控開(kai)關(guan)閉(bi)合跟斷(duan)開(kai)的(de)時(shi)(shi)刻（即PWM——脈沖寬度調制(zhi)），就能夠(gou)操(cao)控輸(shu)出(chu)電壓。假如經(jing)過(guo)檢(jian)測輸(shu)出(chu)電壓來操(cao)控開(kai)、關(guan)的(de)時(shi)(shi)刻，以堅(jian)持輸(shu)出(chu)電壓不(bu)變，這就完成了穩壓的(de)目(mu)的(de)。

一般(ban)(ban)(ban)電(dian)(dian)源(yuan)(yuan)(yuan)(yuan)和開(kai)關(guan)電(dian)(dian)源(yuan)(yuan)(yuan)(yuan)相(xiang)同(tong)的是都有電(dian)(dian)壓(ya)(ya)調整(zheng)(zheng)管，運用(yong)(yong)反(fan)響原理來(lai)進行(xing)穩壓(ya)(ya)的，不(bu)同(tong)的是開(kai)關(guan)電(dian)(dian)源(yuan)(yuan)(yuan)(yuan)運用(yong)(yong)開(kai)關(guan)管進行(xing)調整(zheng)(zheng)，一般(ban)(ban)(ban)電(dian)(dian)源(yuan)(yuan)(yuan)(yuan)一般(ban)(ban)(ban)運用(yong)(yong)三(san)極管的線性放大(da)區進行(xing)調整(zheng)(zheng)。比較而言(yan)，開(kai)關(guan)電(dian)(dian)源(yuan)(yuan)(yuan)(yuan)的能耗(hao)低，對交流電(dian)(dian)壓(ya)(ya)適用(yong)(yong)范圍(wei)要寬，輸出直流的波紋系數要好，缺(que)點是開(kai)關(guan)脈沖煩擾。

一般半橋(qiao)開(kai)(kai)關(guan)(guan)電(dian)(dian)源的首(shou)要作業(ye)原理(li)便是上(shang)橋(qiao)和下(xia)(xia)橋(qiao)的開(kai)(kai)關(guan)(guan)管(guan)(頻率高(gao)時開(kai)(kai)關(guan)(guan)管(guan)為VMOS)輪番導通(tong)，首(shou)要電(dian)(dian)流經過(guo)上(shang)橋(qiao)開(kai)(kai)關(guan)(guan)管(guan)流入(ru)，運(yun)用電(dian)(dian)感線(xian)圈(quan)(quan)的存(cun)儲功(gong)能(neng)(neng)，將電(dian)(dian)能(neng)(neng)集聚在線(xian)圈(quan)(quan)中，畢竟關(guan)(guan)閉上(shang)橋(qiao)開(kai)(kai)關(guan)(guan)管(guan)，翻(fan)開(kai)(kai)下(xia)(xia)橋(qiao)的開(kai)(kai)關(guan)(guan)管(guan)，電(dian)(dian)感線(xian)圈(quan)(quan)和電(dian)(dian)容繼續給外部(bu)供電(dian)(dian)。然后又關(guan)(guan)閉下(xia)(xia)橋(qiao)開(kai)(kai)關(guan)(guan)管(guan)，再翻(fan)開(kai)(kai)上(shang)橋(qiao)讓電(dian)(dian)流進入(ru)，就這(zhe)樣重復進行，因為要輪番開(kai)(kai)關(guan)(guan)兩開(kai)(kai)關(guan)(guan)管(guan)，所以稱為開(kai)(kai)關(guan)(guan)電(dian)(dian)源。

而線性(xing)電源(yuan)就(jiu)不相同(tong)了，因為沒有(you)開關介入(ru)，使得上水(shui)管(guan)一直在放水(shui)，假如(ru)有(you)多(duo)的(de)(de)，就(jiu)會(hui)漏出來(lai)，這便是咱(zan)們常常看到的(de)(de)某些線性(xing)電源(yuan)的(de)(de)調(diao)整管(guan)發熱量(liang)很大，用不完的(de)(de)電能(neng)，全部轉化(hua)成(cheng)了熱能(neng)。從這個視點來(lai)看，線性(xing)電源(yuan)的(de)(de)轉化(hua)功(gong)率(lv)就(jiu)非常低(di)了，而且熱量(liang)高的(de)(de)時分(fen)，元件的(de)(de)壽數勢(shi)必要(yao)下(xia)降，影響(xiang)畢竟的(de)(de)運用效(xiao)果。

首要差異：作業方案

線(xian)性(xing)電源(yuan)的功(gong)(gong)率(lv)調整管(guan)總是作業在(zai)放(fang)大區，流(liu)過(guo)的電流(liu)是接連的。因為調整管(guan)上損耗較大的功(gong)(gong)率(lv)，所以需(xu)求較大功(gong)(gong)率(lv)調整管(guan)并裝有(you)體積很大的散(san)熱(re)器，發熱(re)嚴(yan)峻，功(gong)(gong)率(lv)很低，一般在(zai)40%~60%（還得說是很好的線(xian)性(xing)電源(yuan)）。

線性電(dian)源的(de)作業方案，使(shi)從高(gao)壓(ya)(ya)(ya)變(bian)低壓(ya)(ya)(ya)必須有(you)將壓(ya)(ya)(ya)裝置，一(yi)般的(de)都(dou)是(shi)變(bian)壓(ya)(ya)(ya)器(qi)，也有(you)其他像KX電(dian)源，再經(jing)過整流輸出直流電(dian)壓(ya)(ya)(ya)。這樣一(yi)來體積也就很大，比較粗笨，功(gong)率低、發(fa)熱量也大；但也有(you)利益：紋波小(xiao)、調整率好、對外煩擾小(xiao)、適合用與模擬(ni)電(dian)路/各類放大器(qi)等(deng)。

開(kai)關電(dian)(dian)(dian)(dian)源(yuan)它的(de)功(gong)率(lv)器(qi)材作業在開(kai)關狀(zhuang)況，在電(dian)(dian)(dian)(dian)壓(ya)(ya)調(diao)(diao)整時能量是(shi)經過電(dian)(dian)(dian)(dian)感線圈(quan)來暫時儲存(cun)，這樣他的(de)損耗就(jiu)小(xiao)(xiao)，功(gong)率(lv)也就(jiu)高，對(dui)散(san)熱的(de)要求低，但它對(dui)變壓(ya)(ya)器(qi)和貯能電(dian)(dian)(dian)(dian)感也有(you)(you)了(le)**的(de)要求，要用低損耗高磁(ci)導率(lv)的(de)材料來做。它的(de)變壓(ya)(ya)器(qi)便是(shi)一個(ge)字小(xiao)(xiao)。總功(gong)率(lv)在80%～98%，開(kai)關電(dian)(dian)(dian)(dian)源(yuan)的(de)功(gong)率(lv)高但體積小(xiao)(xiao)，但是(shi)和線性電(dian)(dian)(dian)(dian)源(yuan)比他的(de)紋波(bo)，電(dian)(dian)(dian)(dian)壓(ya)(ya)電(dian)(dian)(dian)(dian)流調(diao)(diao)整率(lv)就(jiu)有(you)(you)必定的(de)折(zhe)扣了(le)。