一、電源模塊常見異常有哪些

1、輸入電壓過高

電源模塊輸(shu)入電壓過(guo)高，輕則(ze)導致(zhi)系統無法正常工(gong)作，重(zhong)則(ze)燒毀電路。

2、輸出電壓過低

電源模塊輸出(chu)(chu)電壓過低(di)(di)(di)，可能會(hui)導致整體系統不能正常(chang)工作(zuo)，如微控(kong)(kong)制器系統中，負載突然增大，會(hui)拉低(di)(di)(di)微控(kong)(kong)制器供電電壓，容易(yi)造(zao)成復位。并且電源長時間低(di)(di)(di)電壓工作(zuo)，電路的壽(shou)命會(hui)出(chu)(chu)現極大的折損。

3、輸出紋波噪聲過大

輸出紋波噪(zao)聲過大(da)的(de)原因：電(dian)(dian)源(yuan)(yuan)模塊與主電(dian)(dian)路噪(zao)聲敏感(gan)元(yuan)件距離過近、主電(dian)(dian)路噪(zao)聲敏感(gan)元(yuan)件的(de)電(dian)(dian)源(yuan)(yuan)輸入端處未接(jie)去耦電(dian)(dian)等(deng)。

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4、電源耐壓不良

電源模(mo)塊的耐壓值一般高達幾千(qian)伏，不(bu)過在應用或者(zhe)測試中可能會出現達不(bu)到指標的情況(kuang)。

二、電源模塊維修教程

1、無輸出，保險管正常。這種現象說(shuo)明(ming)開(kai)關電(dian)(dian)(dian)(dian)(dian)(dian)源未工作或(huo)進入了保護狀態。首(shou)先要測(ce)量(liang)(liang)電(dian)(dian)(dian)(dian)(dian)(dian)源控(kong)制(zhi)(zhi)(zhi)芯(xin)片的(de)啟動腳是否有(you)(you)啟動電(dian)(dian)(dian)(dian)(dian)(dian)壓，若(ruo)(ruo)無啟動電(dian)(dian)(dian)(dian)(dian)(dian)壓或(huo)者啟動電(dian)(dian)(dian)(dian)(dian)(dian)壓太低(di)(di)，則(ze)要檢(jian)查(cha)(cha)啟動電(dian)(dian)(dian)(dian)(dian)(dian)阻和啟動腳外接的(de)元(yuan)件是否漏電(dian)(dian)(dian)(dian)(dian)(dian)，此時如電(dian)(dian)(dian)(dian)(dian)(dian)源控(kong)制(zhi)(zhi)(zhi)芯(xin)片正常，則(ze)經上述檢(jian)查(cha)(cha)可以迅速查(cha)(cha)到故障。若(ruo)(ruo)有(you)(you)啟動電(dian)(dian)(dian)(dian)(dian)(dian)壓，則(ze)測(ce)量(liang)(liang)控(kong)制(zhi)(zhi)(zhi)芯(xin)片的(de)輸出端在開(kai)機瞬間(jian)是否有(you)(you)高、低(di)(di)電(dian)(dian)(dian)(dian)(dian)(dian)平的(de)跳變(bian)，若(ruo)(ruo)無跳變(bian)，說(shuo)明(ming)控(kong)制(zhi)(zhi)(zhi)芯(xin)片壞、外圍振蕩電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)元(yuan)件或(huo)保護電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)有(you)(you)問題，可先代換控(kong)制(zhi)(zhi)(zhi)芯(xin)片，再檢(jian)查(cha)(cha)外圍元(yuan)件;若(ruo)(ruo)有(you)(you)跳變(bian)，一般為開(kai)關管不良或(huo)損壞。

2、保險燒或炸。主要檢(jian)查300V上的大濾波電容、整流(liu)橋各二極管及開(kai)關管等部位，抗干擾電路出(chu)問題也(ye)會(hui)導(dao)致(zhi)保(bao)險(xian)(xian)燒(shao)(shao)、發(fa)黑。需要注意的是(shi)：因開(kai)關管擊穿導(dao)致(zhi)保(bao)險(xian)(xian)燒(shao)(shao)一般會(hui)把電流(liu)檢(jian)測電阻(zu)和電源控制(zhi)芯片燒(shao)(shao)壞。負溫度系數(shu)熱敏電阻(zu)也(ye)很容易(yi)和保(bao)險(xian)(xian)一起(qi)被燒(shao)(shao)壞。

3、有輸出電壓，但輸出電壓過高。這種(zhong)故障一般來自于穩壓取(qu)樣(yang)和穩壓控制電(dian)(dian)路。在直(zhi)流輸出、取(qu)樣(yang)電(dian)(dian)阻、誤差取(qu)樣(yang)放大器如TL431、光(guang)耦、電(dian)(dian)源控制芯片(pian)等電(dian)(dian)路共同構成一個(ge)閉合的控制環(huan)路，任(ren)何一處出問(wen)題就會(hui)導致輸出電(dian)(dian)壓升高。

4、輸出電壓過低。除穩壓(ya)控制電(dian)(dian)路會(hui)引起輸出電(dian)(dian)壓(ya)低，還有下面一些(xie)原因也會(hui)引起輸出電(dian)(dian)壓(ya)低：

（1）輸出電(dian)壓(ya)端整流二極管、濾波電(dian)容失效等(deng)，可以通過代換法(fa)進行(xing)判斷。

（2）開(kai)關(guan)管的性能下降，必然(ran)導(dao)致(zhi)開(kai)關(guan)管不能正常導(dao)通(tong)，使(shi)電源的內阻增加，帶(dai)負(fu)載能力下降。