電腦電源的組成部分

1、濾波器

一(yi)個電(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)通常(chang)包含(han)不(bu)止一(yi)個電(dian)(dian)(dian)(dian)(dian)磁濾(lv)波器，第(di)一(yi)個位于市(shi)(shi)電(dian)(dian)(dian)(dian)(dian)接(jie)入電(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)的(de)(de)(de)位置(zhi)，可(ke)以在(zai)一(yi)個電(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)的(de)(de)(de)220V市(shi)(shi)電(dian)(dian)(dian)(dian)(dian)接(jie)口背后發現它。其電(dian)(dian)(dian)(dian)(dian)路主(zhu)要作用是濾(lv)除外(wai)界的(de)(de)(de)突發脈沖和高頻干(gan)擾，另一(yi)方面也(ye)會減少開(kai)關(guan)電(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)本身對(dui)外(wai)界的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)磁干(gan)擾。它的(de)(de)(de)結構雖然簡單，大(da)都(dou)由X電(dian)(dian)(dian)(dian)(dian)容、Y電(dian)(dian)(dian)(dian)(dian)容和變壓器型電(dian)(dian)(dian)(dian)(dian)感(gan)組成，但卻是電(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)中的(de)(de)(de)重(zhong)要設備，如果在(zai)這上面偷工減料的(de)(de)(de)話(hua)，電(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)的(de)(de)(de)屏蔽(bi)性能將大(da)打折扣。如果拿優(you)質名牌電(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)和普通雜牌電(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)比(bi)較的(de)(de)(de)話(hua)，會發現大(da)部分雜牌電(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)都(dou)缺少EMI電(dian)(dian)(dian)(dian)(dian)路，電(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)直接(jie)從市(shi)(shi)電(dian)(dian)(dian)(dian)(dian)引入PCB。而這一(yi)點也(ye)就成為區分電(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)質量優(you)秀與否的(de)(de)(de)核(he)心(xin)之一(yi)了。

此外，很多品牌優(you)質電(dian)(dian)源為保證輸入到整流(liu)電(dian)(dian)路(lu)中的電(dian)(dian)流(liu)的純凈，還都設(she)計(ji)了第(di)二道濾波電(dian)(dian)路(lu)。此濾波電(dian)(dian)路(lu)同(tong)樣(yang)也是由X電(dian)(dian)容、Y電(dian)(dian)容和變壓器型電(dian)(dian)感組成，位(wei)置(zhi)位(wei)于PCB上(shang)，靠(kao)近第(di)一(yi)道EMI電(dian)(dian)路(lu)附近。

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2、保護器--壓敏電阻

壓敏電(dian)(dian)阻是每個電(dian)(dian)源必不可少的(de)元件，散布在(zai)印(yin)刷電(dian)(dian)路板（PCB）上(shang)，其作用(yong)是對電(dian)(dian)源提供保護。它的(de)原理基(ji)本(ben)和家里的(de)保險絲類似，使用(yong)自我熔斷方式切斷電(dian)(dian)流(liu)。

3、濾波電路

稍(shao)微學過一(yi)(yi)點電(dian)(dian)(dian)子(zi)電(dian)(dian)(dian)路的(de)(de)(de)人都知道：交流轉（脈(mo)沖）直流必須經過一(yi)(yi)個(ge)整(zheng)流濾(lv)波(bo)(bo)電(dian)(dian)(dian)路。最(zui)(zui)常(chang)見的(de)(de)(de)就(jiu)是由四個(ge)二(er)極(ji)管和(he)兩(liang)(liang)個(ge)濾(lv)波(bo)(bo)電(dian)(dian)(dian)容組成的(de)(de)(de)橋式濾(lv)波(bo)(bo)電(dian)(dian)(dian)路。計(ji)算機電(dian)(dian)(dian)源通常(chang)都采用這種(zhong)方式整(zheng)流。根據封(feng)裝模式不同，計(ji)算機電(dian)(dian)(dian)源中常(chang)見的(de)(de)(de)整(zheng)流濾(lv)波(bo)(bo)電(dian)(dian)(dian)路常(chang)見的(de)(de)(de)有(you)兩(liang)(liang)種(zhong)：一(yi)(yi)種(zhong)是獨立四個(ge)二(er)極(ji)管組成，另外一(yi)(yi)種(zhong)將四個(ge)二(er)極(ji)管封(feng)裝在一(yi)(yi)起(qi)，稱為“全(quan)橋”。無論(lun)全(quan)橋還(huan)是獨立二(er)極(ji)管，所能承受(shou)的(de)(de)(de)最(zui)(zui)低耐壓(ya)(ya)和(he)最(zui)(zui)大電(dian)(dian)(dian)流都是有(you)限(xian)制的(de)(de)(de)：耐壓(ya)(ya)應不低于(yu)700V，最(zui)(zui)大電(dian)(dian)(dian)流應不小(xiao)于(yu)1A。

4、變壓器

在電(dian)源中(zhong)，變(bian)壓(ya)器是將(jiang)高壓(ya)轉換(huan)為低(di)壓(ya)，供電(dian)腦使用。根據電(dian)磁學原理，變(bian)壓(ya)器的(de)轉換(huan)比率主(zhu)要由其線圈的(de)匝數決定(ding)，因此個頭(tou)越大的(de)開關型變(bian)壓(ya)器往(wang)往(wang)可(ke)以傳遞更多的(de)能量(liang)，也是分辨(bian)優(you)質或低(di)劣電(dian)源的(de)觀察(cha)點(dian)之一，一定(ding)程度(du)上(shang)，變(bian)壓(ya)器的(de)個頭(tou)直接影響電(dian)源的(de)真正輸出(chu)功率和品質。

開關三極管是電源的(de)中心(xin)樞紐(niu)，它主要負責將(jiang)轉換后的(de)高壓(ya)直流輸送到開(kai)關(guan)變壓(ya)器上進行降壓(ya)，其耐壓(ya)程(cheng)度不得(de)小(xiao)于800V，輸出電流通常不能小(xiao)于5A。開(kai)關(guan)三極管(guan)屬于核心(xin)易(yi)損(sun)部件(jian)，又是(shi)電源(yuan)的(de)核心(xin)部分，所以(yi)開(kai)關(guan)三極管(guan)的(de)質量和(he)電源(yuan)本身的(de)品質也(ye)是(shi)息息相關(guan)的(de)。

5、保護電路

電(dian)(dian)(dian)(dian)源內(nei)部的(de)保(bao)(bao)護(hu)電(dian)(dian)(dian)(dian)路(lu)(lu)監視著電(dian)(dian)(dian)(dian)源的(de)一(yi)舉一(yi)動，是電(dian)(dian)(dian)(dian)源的(de)大腦。它(ta)負責啟動電(dian)(dian)(dian)(dian)源并(bing)進行電(dian)(dian)(dian)(dian)壓(ya)/電(dian)(dian)(dian)(dian)流(liu)的(de)監控和調(diao)整(zheng)，同(tong)時在出(chu)現短(duan)路(lu)(lu)、斷(duan)路(lu)(lu)、過(guo)壓(ya)、過(guo)流(liu)、欠壓(ya)、欠流(liu)等情況(kuang)的(de)時候進行自動保(bao)(bao)護(hu)。劣質電(dian)(dian)(dian)(dian)源通(tong)常會簡化這部分電(dian)(dian)(dian)(dian)路(lu)(lu)甚(shen)至根(gen)本(ben)不設(she)置(zhi)保(bao)(bao)護(hu)電(dian)(dian)(dian)(dian)路(lu)(lu)，而這一(yi)切都會給電(dian)(dian)(dian)(dian)腦系統帶來(lai)諸多隱患。

根據(ju)保(bao)護(hu)(hu)(hu)電(dian)(dian)(dian)(dian)路的位置和監控的類(lei)型(xing)(xing)不同，電(dian)(dian)(dian)(dian)源內部(bu)的保(bao)護(hu)(hu)(hu)電(dian)(dian)(dian)(dian)路又分為(wei)輸(shu)入端過(guo)壓保(bao)護(hu)(hu)(hu)、輸(shu)入端過(guo)流(liu)(liu)(liu)保(bao)護(hu)(hu)(hu)、輸(shu)出(chu)端過(guo)壓保(bao)護(hu)(hu)(hu)和輸(shu)出(chu)端過(guo)流(liu)(liu)(liu)保(bao)護(hu)(hu)(hu)四個類(lei)型(xing)(xing)，這也是大部(bu)分優(you)質品牌電(dian)(dian)(dian)(dian)源宣傳的“四重保(bao)護(hu)(hu)(hu)電(dian)(dian)(dian)(dian)路”的由來。顧名思義(yi)，過(guo)壓/過(guo)流(liu)(liu)(liu)保(bao)護(hu)(hu)(hu)電(dian)(dian)(dian)(dian)路也就是監視的輸(shu)入/輸(shu)出(chu)電(dian)(dian)(dian)(dian)壓/電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)出(chu)現異常(chang)時自動(dong)生效，從(cong)而達到保(bao)護(hu)(hu)(hu)作(zuo)用。

此(ci)外優質電源通常還設(she)置有輸出端短路保護。這是個非常實用的功(gong)能。

6、電路部分

在(zai)國(guo)家(jia)強(qiang)制實施(shi)的(de)(de)3C認證中，要(yao)求電(dian)(dian)源(yuan)內部(bu)必須增(zeng)加一(yi)(yi)個(ge)功率(lv)因素校(xiao)正電(dian)(dian)路，以(yi)(yi)減少開關電(dian)(dian)源(yuan)對外部(bu)電(dian)(dian)網(wang)的(de)(de)干擾，這(zhe)就是現在(zai)電(dian)(dian)源(yuan)內部(bu)的(de)(de)PFC電(dian)(dian)路。所(suo)以(yi)(yi)最(zui)新(xin)通過(guo)國(guo)家(jia)CCC認證的(de)(de)電(dian)(dian)源(yuan)內部(bu)都會出(chu)現一(yi)(yi)個(ge)新(xin)的(de)(de)部(bu)件(jian)(jian)，PFC電(dian)(dian)路。通過(guo)本次對數十款電(dian)(dian)源(yuan)的(de)(de)拆卸，可(ke)以(yi)(yi)發現常見PFC電(dian)(dian)路其實就是一(yi)(yi)個(ge)無源(yuan)電(dian)(dian)感，其成本大約在(zai)5-6元人民(min)幣左(zuo)右，個(ge)頭比開關變壓器還(huan)要(yao)大，樣子很像開關變壓器，同樣用黃色膠帶封裝。還(huan)有一(yi)(yi)些追求空間的(de)(de)緊(jin)湊型產(chan)品或者追求性能表現的(de)(de)電(dian)(dian)源(yuan)產(chan)品會使用成本在(zai)20-30元的(de)(de)有源(yuan)PFC元器件(jian)(jian)，個(ge)頭小但是功率(lv)因數可(ke)以(yi)(yi)接(jie)近于一(yi)(yi)，效果十分優秀。

7、散熱部分

電(dian)腦電(dian)源(yuan)(yuan)的(de)轉換(huan)效率(lv)(lv)通(tong)常在70-80%之間，這(zhe)(zhe)就意味著20-30%的(de) 能(neng)量(liang)(liang)將轉化為熱量(liang)(liang)。這(zhe)(zhe)些熱量(liang)(liang)積聚(ju)在電(dian)源(yuan)(yuan)中不能(neng)及(ji)時散(san)發(fa)，會使電(dian)源(yuan)(yuan)局部(bu)溫度過高，從(cong)而對(dui)電(dian)源(yuan)(yuan)造成(cheng)不必要(yao)的(de)傷(shang)害。因此(ci)任何電(dian)源(yuan)(yuan)內部(bu)都包含有散(san)熱裝置，由(you)此(ci)得來(lai)的(de)風扇排 風量(liang)(liang)和(he)噪(zao)音指數(shu)也是(shi)電(dian)源(yuan)(yuan)的(de)兩個重要(yao)指標。電(dian)源(yuan)(yuan)散(san)熱主要(yao)通(tong)過散(san)熱片(pian)和(he)功(gong)(gong)率(lv)(lv)管配合進(jin)行，從(cong)縫隙中望進(jin)去，都能(neng)看到電(dian)源(yuan)(yuan)內部(bu)有巨大的(de)散(san)熱片(pian)，上面(mian)的(de)大功(gong)(gong)率(lv)(lv)管 的(de)性能(neng)和(he)極限(xian)參數(shu)直接(jie)影響(xiang)到電(dian)源(yuan)(yuan)的(de)安(an)全承載功(gong)(gong)率(lv)(lv)和(he)產品成(cheng)本，也與電(dian)源(yuan)(yuan)的(de)余量(liang)(liang)大小密切相關(guan)。所以說(shuo)觀察(cha)散(san)熱片(pian)和(he)上面(mian)的(de)功(gong)(gong)率(lv)(lv)管也是(shi)判斷一(yi)個電(dian)源(yuan)(yuan)好與壞的(de)方(fang)法(fa)。