開(kai)關(guan)(guan)電(dian)(dian)源(yuan)是各種電(dian)(dian)子(zi)設備必不可缺(que)的(de)組成(cheng)部(bu)分(fen)，其性(xing)能優劣直接關(guan)(guan)系到電(dian)(dian)子(zi)設備的(de)技術(shu)指標及能否安全可靠地工作。由于開(kai)關(guan)(guan)電(dian)(dian)源(yuan)內部(bu)關(guan)(guan)鍵元器件工作在(zai)高頻開(kai)關(guan)(guan)狀態，功耗(hao)小(xiao)，轉化(hua)率高，且體積和重量只有線性(xing)電(dian)(dian)源(yuan)的(de)20%—30%，故(gu)目前它已成(cheng)為穩壓電(dian)(dian)源(yuan)的(de)主流產品。今天飛天鷹為大家介(jie)紹一下開(kai)關(guan)(guan)電(dian)(dian)源(yuan)在(zai)使(shi)用中一些(xie)(xie)常見的(de)故(gu)障，為維修(xiu)開(kai)關(guan)(guan)電(dian)(dian)源(yuan)提(ti)供一些(xie)(xie)建議(yi)。

1. 無輸(shu)出，保險管正常

這種現(xian)象說(shuo)明開關(guan)電(dian)(dian)(dian)源(yuan)未(wei)工作或(huo)進入了保護(hu)狀態。首先(xian)要測(ce)量電(dian)(dian)(dian)源(yuan)控制(zhi)(zhi)芯(xin)片的(de)(de)啟(qi)(qi)動腳是(shi)(shi)否(fou)有(you)(you)啟(qi)(qi)動電(dian)(dian)(dian)壓，若無(wu)啟(qi)(qi)動電(dian)(dian)(dian)壓或(huo)者(zhe)啟(qi)(qi)動電(dian)(dian)(dian)壓太低，則要檢(jian)查啟(qi)(qi)動電(dian)(dian)(dian)阻和啟(qi)(qi)動腳外(wai)接的(de)(de)元(yuan)件是(shi)(shi)否(fou)漏電(dian)(dian)(dian)，此時如(ru)電(dian)(dian)(dian)源(yuan)控制(zhi)(zhi)芯(xin)片正常(chang)，則經上述檢(jian)查可(ke)以迅速查到故障(zhang)。若有(you)(you)啟(qi)(qi)動電(dian)(dian)(dian)壓，則測(ce)量控制(zhi)(zhi)芯(xin)片的(de)(de)輸出(chu)端(duan)在開機(ji)瞬間是(shi)(shi)否(fou)有(you)(you)高(gao)、低電(dian)(dian)(dian)平(ping)的(de)(de)跳(tiao)變，若無(wu)跳(tiao)變，說(shuo)明控制(zhi)(zhi)芯(xin)片壞、外(wai)圍振蕩(dang)電(dian)(dian)(dian)路(lu)元(yuan)件或(huo)保護(hu)電(dian)(dian)(dian)路(lu)有(you)(you)問題，可(ke)先(xian)代換(huan)控制(zhi)(zhi)芯(xin)片，再(zai)檢(jian)查外(wai)圍元(yuan)件;若有(you)(you)跳(tiao)變，一般為開關(guan)管不良或(huo)損壞。

　2. 保險燒或炸(zha)

　　主(zhu)要檢(jian)查300V上的(de)大濾(lv)波電(dian)容(rong)、整流橋各二(er)極管及開關(guan)管等(deng)部位，抗干擾電(dian)路出問題也(ye)會導致保(bao)(bao)險(xian)燒、發黑。需要注意的(de)是：因開關(guan)管擊穿導致保(bao)(bao)險(xian)燒一般會把電(dian)流檢測電(dian)阻(zu)和電(dian)源控制(zhi)芯片(pian)燒壞(huai)。負(fu)溫度(du)系數熱敏(min)電(dian)阻(zu)也(ye)很容(rong)易和保(bao)(bao)險(xian)一起被燒壞(huai)。

3. 有輸(shu)出(chu)電壓，但(dan)輸(shu)出(chu)電壓過高

這種故障一(yi)般來自于穩壓取(qu)樣(yang)和穩壓控(kong)制電路(lu)。在(zai)直流輸出、取(qu)樣(yang)電阻、誤差取(qu)樣(yang)放大器(qi)如TL431、光耦、電源控(kong)制芯片等(deng)電路(lu)共同構成一(yi)個閉合的控(kong)制環路(lu)，任何(he)一(yi)處出問題(ti)就會導致輸出電壓升高。