一、電源模塊常見異常有哪些

1、輸入電壓過高

電源模塊(kuai)輸(shu)入(ru)電壓(ya)過(guo)高(gao)，輕則導致系統無(wu)法正(zheng)常工作(zuo)，重則燒毀(hui)電路。

2、輸出電壓過低

電源模塊輸出電(dian)壓過低(di)，可能會導致整體系(xi)統(tong)不(bu)能正常工作(zuo)，如微控(kong)制器系(xi)統(tong)中，負載突然增大，會拉低(di)微控(kong)制器供電(dian)電(dian)壓，容(rong)易造成(cheng)復位。并(bing)且(qie)電(dian)源長時間低(di)電(dian)壓工作(zuo)，電(dian)路的壽命會出現(xian)極大的折損。

3、輸出紋波噪聲過大

輸(shu)出(chu)紋波(bo)噪(zao)聲過(guo)大的原因：電源模塊與主(zhu)電路(lu)噪(zao)聲敏感(gan)元件(jian)距離過(guo)近、主(zhu)電路(lu)噪(zao)聲敏感(gan)元件(jian)的電源輸(shu)入(ru)端(duan)處未接去耦電等(deng)。

該圖片由注冊用戶"淺嘗不止—"提供，版權聲明反饋

4、電源耐壓不良

電(dian)源(yuan)模塊(kuai)的耐壓值一般高達(da)幾千伏，不(bu)過在應用(yong)或者測試中(zhong)可(ke)能會出現達(da)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)開關(guan)(guan)電(dian)(dian)(dian)源未工(gong)作或進入了保(bao)護狀態(tai)。首先(xian)要測(ce)量(liang)電(dian)(dian)(dian)源控(kong)(kong)制芯(xin)片的(de)(de)啟(qi)(qi)(qi)動(dong)(dong)(dong)腳是(shi)否(fou)有啟(qi)(qi)(qi)動(dong)(dong)(dong)電(dian)(dian)(dian)壓(ya)，若(ruo)無啟(qi)(qi)(qi)動(dong)(dong)(dong)電(dian)(dian)(dian)壓(ya)或者(zhe)啟(qi)(qi)(qi)動(dong)(dong)(dong)電(dian)(dian)(dian)壓(ya)太低，則(ze)(ze)要檢查啟(qi)(qi)(qi)動(dong)(dong)(dong)電(dian)(dian)(dian)阻和啟(qi)(qi)(qi)動(dong)(dong)(dong)腳外(wai)接的(de)(de)元(yuan)件(jian)是(shi)否(fou)漏(lou)電(dian)(dian)(dian)，此時(shi)如電(dian)(dian)(dian)源控(kong)(kong)制芯(xin)片正常，則(ze)(ze)經上述(shu)檢查可(ke)以迅速查到故(gu)障。若(ruo)有啟(qi)(qi)(qi)動(dong)(dong)(dong)電(dian)(dian)(dian)壓(ya)，則(ze)(ze)測(ce)量(liang)控(kong)(kong)制芯(xin)片的(de)(de)輸出端在開機瞬(shun)間是(shi)否(fou)有高、低電(dian)(dian)(dian)平的(de)(de)跳(tiao)變(bian)(bian)，若(ruo)無跳(tiao)變(bian)(bian)，說(shuo)明(ming)控(kong)(kong)制芯(xin)片壞、外(wai)圍振(zhen)蕩電(dian)(dian)(dian)路元(yuan)件(jian)或保(bao)護電(dian)(dian)(dian)路有問題，可(ke)先(xian)代換控(kong)(kong)制芯(xin)片，再(zai)檢查外(wai)圍元(yuan)件(jian);若(ruo)有跳(tiao)變(bian)(bian)，一般(ban)為開關(guan)(guan)管不良或損壞。

2、保險燒或炸。主要檢查300V上的(de)大(da)濾(lv)波電(dian)(dian)容(rong)、整流橋各(ge)二(er)極管(guan)及(ji)開關管(guan)等部位，抗干擾電(dian)(dian)路出問題也會導致(zhi)保(bao)險(xian)(xian)燒(shao)、發黑。需(xu)要注意的(de)是：因(yin)開關管(guan)擊穿導致(zhi)保(bao)險(xian)(xian)燒(shao)一般會把電(dian)(dian)流檢測電(dian)(dian)阻(zu)和電(dian)(dian)源(yuan)控制(zhi)芯(xin)片燒(shao)壞。負溫度系數(shu)熱敏電(dian)(dian)阻(zu)也很(hen)容(rong)易和保(bao)險(xian)(xian)一起被(bei)燒(shao)壞。

3、有輸出電壓，但輸出電壓過高。這種(zhong)故障一般來自(zi)于穩壓(ya)取樣和穩壓(ya)控(kong)(kong)制電(dian)路。在(zai)直流(liu)輸(shu)出、取樣電(dian)阻、誤差取樣放大器如TL431、光耦、電(dian)源控(kong)(kong)制芯片等電(dian)路共同(tong)構成一個閉合的控(kong)(kong)制環(huan)路，任何一處出問題就會導致輸(shu)出電(dian)壓(ya)升高。

4、輸出電壓過低。除穩壓控制電路會引(yin)起輸(shu)出電壓低，還(huan)有下面一(yi)些原因也會引(yin)起輸(shu)出電壓低：

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

（2）開關管(guan)的性能(neng)下降，必然導致開關管(guan)不能(neng)正(zheng)常導通，使電(dian)源的內阻增加，帶(dai)負載(zai)能(neng)力下降。