一、電源模塊常見異常有哪些
1、輸入電壓過高
電(dian)源模塊輸入電(dian)壓過高(gao),輕則導致(zhi)系(xi)統無(wu)法正常工作,重則燒毀(hui)電(dian)路(lu)。
2、輸出電壓過低
電源模塊輸出電(dian)壓(ya)過低,可能會(hui)(hui)導致(zhi)整(zheng)體系統(tong)不(bu)能正常工作,如微(wei)控制器(qi)系統(tong)中,負載(zai)突然(ran)增大(da),會(hui)(hui)拉(la)低微(wei)控制器(qi)供電(dian)電(dian)壓(ya),容(rong)易造成復位。并且電(dian)源長時間低電(dian)壓(ya)工作,電(dian)路的壽命(ming)會(hui)(hui)出現(xian)極大(da)的折損。
3、輸出紋波噪聲過大
輸出(chu)紋(wen)波噪(zao)聲過大(da)的(de)原因:電源模塊與主電路(lu)噪(zao)聲敏感元(yuan)件距(ju)離過近、主電路(lu)噪(zao)聲敏感元(yuan)件的(de)電源輸入(ru)端(duan)處未(wei)接去耦電等。
4、電源耐壓不良
電(dian)源(yuan)模(mo)塊(kuai)的耐壓值(zhi)一般高達(da)幾(ji)千伏,不過在(zai)應用(yong)或(huo)者(zhe)測試中可能會出現達(da)不到指(zhi)標(biao)的情況。
二、電源模塊維修教程
1、無輸出,保險管正常。這種(zhong)現象(xiang)說明開(kai)(kai)關(guan)電(dian)(dian)(dian)(dian)源未工作或(huo)(huo)進入了保護狀態(tai)。首先(xian)要(yao)測量電(dian)(dian)(dian)(dian)源控(kong)(kong)(kong)制(zhi)(zhi)(zhi)芯(xin)(xin)片(pian)的(de)(de)啟(qi)(qi)(qi)動(dong)(dong)腳是(shi)否(fou)有(you)啟(qi)(qi)(qi)動(dong)(dong)電(dian)(dian)(dian)(dian)壓(ya)(ya),若無(wu)啟(qi)(qi)(qi)動(dong)(dong)電(dian)(dian)(dian)(dian)壓(ya)(ya)或(huo)(huo)者啟(qi)(qi)(qi)動(dong)(dong)電(dian)(dian)(dian)(dian)壓(ya)(ya)太低,則要(yao)檢查啟(qi)(qi)(qi)動(dong)(dong)電(dian)(dian)(dian)(dian)阻和(he)啟(qi)(qi)(qi)動(dong)(dong)腳外(wai)接的(de)(de)元(yuan)件(jian)是(shi)否(fou)漏電(dian)(dian)(dian)(dian),此(ci)時如電(dian)(dian)(dian)(dian)源控(kong)(kong)(kong)制(zhi)(zhi)(zhi)芯(xin)(xin)片(pian)正常(chang),則經上述檢查可以迅(xun)速查到故障(zhang)。若有(you)啟(qi)(qi)(qi)動(dong)(dong)電(dian)(dian)(dian)(dian)壓(ya)(ya),則測量控(kong)(kong)(kong)制(zhi)(zhi)(zhi)芯(xin)(xin)片(pian)的(de)(de)輸出端在開(kai)(kai)機(ji)瞬(shun)間是(shi)否(fou)有(you)高、低電(dian)(dian)(dian)(dian)平的(de)(de)跳變,若無(wu)跳變,說明控(kong)(kong)(kong)制(zhi)(zhi)(zhi)芯(xin)(xin)片(pian)壞、外(wai)圍振蕩電(dian)(dian)(dian)(dian)路元(yuan)件(jian)或(huo)(huo)保護電(dian)(dian)(dian)(dian)路有(you)問題,可先(xian)代換控(kong)(kong)(kong)制(zhi)(zhi)(zhi)芯(xin)(xin)片(pian),再檢查外(wai)圍元(yuan)件(jian);若有(you)跳變,一般為開(kai)(kai)關(guan)管不(bu)良或(huo)(huo)損壞。
2、保險燒或炸。主要檢(jian)(jian)查300V上的(de)大濾波(bo)電(dian)容、整流橋各二極(ji)管(guan)及開(kai)關(guan)管(guan)等部位,抗干(gan)擾電(dian)路出問題(ti)也會導(dao)致(zhi)保(bao)險燒、發黑。需要注意的(de)是:因(yin)開(kai)關(guan)管(guan)擊(ji)穿導(dao)致(zhi)保(bao)險燒一(yi)(yi)般會把電(dian)流檢(jian)(jian)測電(dian)阻和電(dian)源控制芯片(pian)燒壞(huai)(huai)。負溫度系數(shu)熱敏電(dian)阻也很容易和保(bao)險一(yi)(yi)起(qi)被燒壞(huai)(huai)。
3、有輸出電壓,但輸出電壓過高。這種故障一(yi)般來(lai)自于穩壓取(qu)樣和(he)穩壓控(kong)(kong)制電路(lu)。在直流輸(shu)出(chu)、取(qu)樣電阻、誤差取(qu)樣放大器如(ru)TL431、光(guang)耦、電源控(kong)(kong)制芯(xin)片等電路(lu)共同構成一(yi)個閉合的(de)控(kong)(kong)制環(huan)路(lu),任何一(yi)處出(chu)問題就會導致(zhi)輸(shu)出(chu)電壓升高。
4、輸出電壓過低。除(chu)穩壓控制電路會(hui)引起輸出電壓低(di),還有(you)下面一些原(yuan)因也會(hui)引起輸出電壓低(di):
(1)輸出電壓端整流(liu)二極管、濾(lv)波電容失(shi)效(xiao)等,可以(yi)通過代換法進行判斷(duan)。
(2)開關管(guan)的性(xing)能(neng)下降,必然導致開關管(guan)不(bu)能(neng)正常導通,使電源的內阻(zu)增加,帶負載能(neng)力(li)下降。