今天電源(yuan)適配器廠家來和大(da)家談(tan)談(tan)開(kai)關(guan)電源(yuan)設計心得(de)。首(shou)先從(cong)開(kai)關(guan)電源(yuan)的(de)設計及生產工(gong)藝(yi)開(kai)始描(miao)述吧，先說說印制板(ban)的(de)設計。開(kai)關(guan)電源(yuan)工(gong)作在(zai)高(gao)頻(pin)率，高(gao)脈沖狀(zhuang)態，屬于(yu)模擬電路(lu)中的(de)一個比較特殊(shu)種(zhong)類。布板(ban)時須(xu)遵循高(gao)頻(pin)電路(lu)布線原則。

布局：脈沖(chong)電(dian)(dian)(dian)(dian)壓連線盡(jin)可能(neng)短(duan)，其中(zhong)輸入(ru)(ru)開(kai)關(guan)(guan)(guan)管到(dao)(dao)(dao)(dao)變(bian)壓器(qi)(qi)連線，輸出(chu)變(bian)壓器(qi)(qi)到(dao)(dao)(dao)(dao)整(zheng)(zheng)流(liu)管連接(jie)線。脈沖(chong)電(dian)(dian)(dian)(dian)流(liu)環路(lu)(lu)盡(jin)可能(neng)小如(ru)(ru)輸入(ru)(ru)濾波(bo)電(dian)(dian)(dian)(dian)容(rong)(rong)正到(dao)(dao)(dao)(dao)變(bian)壓器(qi)(qi)到(dao)(dao)(dao)(dao)開(kai)關(guan)(guan)(guan)管返(fan)回(hui)電(dian)(dian)(dian)(dian)容(rong)(rong)負。輸出(chu)部(bu)分變(bian)壓器(qi)(qi)出(chu)端(duan)(duan)(duan)到(dao)(dao)(dao)(dao)整(zheng)(zheng)流(liu)管到(dao)(dao)(dao)(dao)輸出(chu)電(dian)(dian)(dian)(dian)感到(dao)(dao)(dao)(dao)輸出(chu)電(dian)(dian)(dian)(dian)容(rong)(rong)返(fan)回(hui)變(bian)壓器(qi)(qi)電(dian)(dian)(dian)(dian)路(lu)(lu)中(zhong)X電(dian)(dian)(dian)(dian)容(rong)(rong)要盡(jin)量接(jie) 近開(kai)關(guan)(guan)(guan)電(dian)(dian)(dian)(dian)源輸入(ru)(ru)端(duan)(duan)(duan)，輸入(ru)(ru)線應(ying)(ying)(ying)避(bi)免與其他電(dian)(dian)(dian)(dian)路(lu)(lu)平行，應(ying)(ying)(ying)避(bi)開(kai)。Y電(dian)(dian)(dian)(dian)容(rong)(rong)應(ying)(ying)(ying)放置在(zai)機(ji)殼接(jie)地端(duan)(duan)(duan)子或FG連接(jie)端(duan)(duan)(duan)。共摸(mo)電(dian)(dian)(dian)(dian)感應(ying)(ying)(ying)與變(bian)壓器(qi)(qi)保持一定距離，以避(bi)免磁偶(ou)合。如(ru)(ru)不(bu)好(hao)處理(li)可在(zai)共摸(mo)電(dian)(dian)(dian)(dian)感與變(bian)壓器(qi)(qi)間(jian)加一屏蔽(bi)，以上幾項對開(kai)關(guan)(guan)(guan)電(dian)(dian)(dian)(dian)源的EMC性(xing)能(neng)影響較大(da)。

下面談一談印制板(ban)布(bu)線的一些(xie)原則

線(xian)(xian)(xian)間距(ju)：隨著印制(zhi)(zhi)線(xian)(xian)(xian)路板制(zhi)(zhi)造(zao)工藝(yi)(yi)的(de)不斷完(wan)善(shan)和(he)提高，一般加工廠制(zhi)(zhi)造(zao)出線(xian)(xian)(xian)間距(ju)等(deng)于(yu)甚(shen)至小(xiao)于(yu)0.1mm已經不存在什么(me)問題，完(wan)全能夠滿足大多數應用場合(he)。考慮到開關電源所采用的(de)元器件及(ji)生產工藝(yi)(yi)，一般雙面(mian)板最小(xiao)線(xian)(xian)(xian)間距(ju)設為0.3mm，單面(mian)板最小(xiao)線(xian)(xian)(xian)間距(ju)設為0.5mm，焊盤(pan)與(yu)(yu)(yu)焊盤(pan)、焊盤(pan)與(yu)(yu)(yu)過孔(kong)或過孔(kong)與(yu)(yu)(yu)過孔(kong)，最小(xiao)間距(ju)設為0.5mm，可(ke)避免在焊接操作過程(cheng)中出現“橋接”現象。，這樣大多數制(zhi)(zhi)板廠都(dou)能夠很輕松滿足生產要求，并可(ke)以(yi)把成(cheng)品率控制(zhi)(zhi)得非(fei)常高，亦可(ke)實(shi)現合(he)理的(de)布(bu)線(xian)(xian)(xian)密度及(ji)有一個較經濟(ji)的(de)成(cheng)本。

談一談印(yin)制板銅皮走線的一些事項(xiang)：

走(zou)線電流密度：現在(zai)多數(shu)電子線路(lu)采用絕緣(yuan)板縛(fu)銅構成。常用線路(lu)板銅皮厚度為35μm，走線可按照(zhao)1A/mm經驗值取電流(liu)密度(du)值，具(ju)體計算可參見教科書。為保證走線(xian)機械強度(du)原則(ze)線(xian)寬應(ying)大(da)于或等于0.3mm(其他非電源線路板(ban)可能最(zui)小(xiao)(xiao)線寬會小(xiao)(xiao)一些)。銅皮(pi)厚度為70μm線路板也(ye)常見于開關(guan)電源，那么電流密(mi)度可更高些。