開關電源是利用現(xian)代電力電子技(ji)術，控制開關管開通(tong)和關斷的(de)時間(jian)比率，維持(chi)穩定輸(shu)出電(dian)(dian)(dian)壓的(de)一(yi)種電(dian)(dian)(dian)源，開關電(dian)(dian)(dian)源一(yi)般由脈沖(chong)寬度調制（PWM）控(kong)制IC和MOSFET構成。隨(sui)著電(dian)(dian)(dian)力電(dian)(dian)(dian)子技術(shu)的(de)發展和創新(xin)，使(shi)得開關電(dian)源技術也在不斷地(di)創(chuang)新(xin)。目前，開關電(dian)源以小型(xing)、輕量和高效率的特點被廣(guang)泛應用幾乎所(suo)有的電(dian)子(zi)設備，是當今電(dian)子(zi)信息產(chan)業飛速發(fa)展不可缺少的一種(zhong)電(dian)源方式。人(ren)們在(zai)開關電(dian)源技術領域是邊(bian)開發相(xiang)關電(dian)力電(dian)子(zi)器(qi)件，邊(bian)開發開關變頻技術，兩者相(xiang)互促進(jin)推動著開關電(dian)源每年以超(chao)過兩位數字的增長(chang)率向(xiang)著(zhu)輕、小、薄、低(di)噪聲、高可靠、抗干擾的方向(xiang)發展。開關電源可分為AC/DC和(he)DC/DC兩大類。

一般(ban)情(qing)況下，保險(xian)絲熔斷說明電(dian)(dian)(dian)(dian)源的內(nei)部線路有問(wen)題。由于電(dian)(dian)(dian)(dian)源工作在高(gao)電(dian)(dian)(dian)(dian)壓(ya)(ya)、大(da)電(dian)(dian)(dian)(dian)流的狀(zhuang)態下，電(dian)(dian)(dian)(dian)網電(dian)(dian)(dian)(dian)壓(ya)(ya)的波(bo)動、浪涌都會(hui)引起(qi)電(dian)(dian)(dian)(dian)源內(nei)電(dian)(dian)(dian)(dian)流瞬間增(zeng)大(da)而使保險(xian)絲熔斷。重點應檢查電(dian)源(yuan)輸入端的整流二極管，高壓(ya)濾波電(dian)解電(dian)容，逆(ni)變(bian)功率開關管等，檢查一下這此元器(qi)件有無擊(ji)穿、開路、損壞等。如果(guo)確實(shi)是保(bao)險絲(si)熔斷(duan)，應該首先(xian)查看電(dian)(dian)路(lu)板上(shang)的(de)各個元件(jian)(jian)，看這些元件(jian)(jian)的(de)外表有沒(mei)(mei)有被燒(shao)糊，有沒(mei)(mei)有電(dian)(dian)解液溢出，如果沒(mei)(mei)有發現上(shang)述情(qing)況，則用(yong)萬用(yong)表測量開關管(guan)有無擊(ji)穿短路(lu)。需要(yao)特別(bie)注意的(de)是(shi)：切(qie)不(bu)可在查(cha)出某元(yuan)件(jian)損(sun)壞時(shi)，更換后直接開機，這樣很有(you)可能由于(yu)其它高(gao)壓(ya)元(yuan)件(jian)仍有(you)故障又將(jiang)更換的(de)元(yuan)件(jian)損(sun)壞，一定要對(dui)上述電路的(de)所有(you)高(gao)壓(ya)元(yuan)件(jian)進行全面檢查測(ce)量后，才(cai)能(neng)徹底(di)排除保(bao)險(xian)絲熔斷(duan)的故(gu)障(zhang)。