從為平板(ban)電(dian)(dian)腦或智能(neng)手機電(dian)(dian)池充電(dian)(dian)到為膝上型(xing)電(dian)(dian)腦或家用路由器(qi)(qi)供(gong)電(dian)(dian)，電(dian)(dian)源適(shi)(shi)配器(qi)(qi)長期以來都是人們日常(chang)生(sheng)活的(de)(de)(de)必要(yao)組成(cheng)部(bu)(bu)分。對于將(jiang)電(dian)(dian)源適(shi)(shi)配器(qi)(qi)與其產(chan)品搭配到一(yi)起(qi)的(de)(de)(de)消(xiao)費(fei)電(dian)(dian)子原設備制(zhi)造商（OEM）而言，需要(yao)因(yin)應兩項(xiang)關鍵推動因(yin)素，即(ji)確保提(ti)供(gong)高能(neng)效等(deng)級并滿足安全(quan)規范，同時(shi)還需提(ti)供(gong)緊湊的(de)(de)(de)外(wai)形因(yin)數(shu)。近年來，由于結合了政府法規及美國“能(neng)源之星”、歐盟(meng)生(sheng)態(tai)設計指令及中國標(biao)準化(hua)研究院（CNIS）等(deng)能(neng)效項(xiang)目，業界非常(chang)注(zhu)重通過減(jian)(jian)小待(dai)機模式下的(de)(de)(de)使用的(de)(de)(de)電(dian)(dian)能(neng)來降(jiang)低適(shi)(shi)配器(qi)(qi)的(de)(de)(de)總體能(neng)耗等(deng)級。本文將(jiang)探討推動最新要(yao)求的(de)(de)(de)新興技術趨(qu)勢，包括要(yao)求減(jian)(jian)少使用的(de)(de)(de)外(wai)部(bu)(bu)元器(qi)(qi)件數(shu)量、使設計更時(shi)髦輕薄的(de)(de)(de)工藝。

　　待機(ji)能(neng)耗有時(shi)候也稱(cheng)作(zuo)“吸血鬼(gui)能(neng)耗”或是(shi)“虛負載”,指的(de)(de)(de)是(shi)電(dian)子設備(bei)及電(dian)器(qi)在關(guan)斷電(dian)源但仍然插(cha)在電(dian)源插(cha)座上時(shi)消耗的(de)(de)(de)電(dian)能(neng)。以美(mei)國為(wei)例，待機(ji)能(neng)耗約(yue)占美(mei)國家庭平均總能(neng)耗約(yue)10%.這(zhe)相當(dang)于(yu)令人驚愕的(de)(de)(de)129太瓦時(shi)（即為(wei)1,290億千瓦時(shi)）的(de)(de)(de)電(dian)能(neng)，或者(zhe)是(shi)36座400兆(zhao)瓦發(fa)電(dian)廠(chang)輸出的(de)(de)(de)電(dian)能(neng)，導致每(mei)年排放7,500萬噸(dun)二氧化碳。

　　在美(mei)(mei)國(guo)(guo)，2008年(nian)7月(yue)1日(ri)生(sheng)效(xiao)(xiao)的(de)(de)(de)現行(xing)聯邦標(biao)準(zhun)(zhun)要求(qiu)(qiu)功(gong)率低(di)于250 W的(de)(de)(de)電(dian)(dian)源空載能(neng)(neng)(neng)耗(hao)低(di)于500 mW.最(zui)近(jin)，美(mei)(mei)國(guo)(guo)能(neng)(neng)(neng)源部（DOE）提出(chu)(chu)了更(geng)嚴格的(de)(de)(de)電(dian)(dian)池充(chong)電(dian)(dian)器及(ji)電(dian)(dian)子產(chan)品電(dian)(dian)源能(neng)(neng)(neng)效(xiao)(xiao)標(biao)準(zhun)(zhun)，并將(jiang)于2013年(nian)7月(yue)1日(ri)生(sheng)效(xiao)(xiao)。根據(ju)新標(biao)準(zhun)(zhun)，銘牌輸出(chu)(chu)功(gong)率介于49至250 W之間（典型筆記(ji)本視頻器功(gong)率位于此范圍）的(de)(de)(de)交流(liu)-直流(liu)（AC-DC）外部電(dian)(dian)源的(de)(de)(de)最(zui)大(da)(da)空載能(neng)(neng)(neng)耗(hao)必須低(di)于0.210 W.然而，這些(xie)國(guo)(guo)家標(biao)準(zhun)(zhun)通常落后(hou)于其它(ta)標(biao)準(zhun)(zhun)及(ji)市場要求(qiu)(qiu)。美(mei)(mei)國(guo)(guo)1975年(nian)能(neng)(neng)(neng)源政(zheng)策及(ji)節(jie)能(neng)(neng)(neng)法案（EPCA）規(gui)定：任(ren)何新的(de)(de)(de)節(jie)能(neng)(neng)(neng)標(biao)準(zhun)(zhun)的(de)(de)(de)制定必須旨在提供最(zui)大(da)(da)程度的(de)(de)(de)能(neng)(neng)(neng)效(xiao)(xiao)提升，不(bu)僅要在技術上可行(xing)，也要具備經濟合理性。因(yin)此，這些(xie)國(guo)(guo)家標(biao)準(zhun)(zhun)通常并不(bu)代表“一流(liu)的(de)(de)(de)”性能(neng)(neng)(neng)。諸多(duo)電(dian)(dian)源制造商(shang)要求(qiu)(qiu)將(jiang)空載能(neng)(neng)(neng)耗(hao)限制到盡可能(neng)(neng)(neng)地(di)低(di)，從而將(jiang)其產(chan)品與(yu)競爭(zheng)產(chan)品區(qu)別開來。

　　圖(tu)1:美國能(neng)源部(bu)提出(chu)的AC-DC外部(bu)電源節能(neng)標準

　　在(zai)能(neng)效標(biao)準上(shang)最為進(jin)取的政府機(ji)構很可(ke)能(neng)是美(mei)(mei)國(guo)加(jia)州(zhou)(zhou)。電(dian)源(yuan)制(zhi)造(zao)商(shang)可(ke)不想提(ti)(ti)供僅針(zhen)對加(jia)州(zhou)(zhou)的特定型號產品，因此，加(jia)州(zhou)(zhou)標(biao)準的實際(ji)影響(xiang)范(fan)圍要廣(guang)得(de)多。例(li)如，美(mei)(mei)國(guo)加(jia)州(zhou)(zhou)在(zai)2012年(nian)1月(yue)出臺的新的電(dian)器(qi)(qi)能(neng)效規范(fan)將電(dian)池充(chong)(chong)電(dian)器(qi)(qi)系統作為重要焦點。加(jia)州(zhou)(zhou)每(mei)年(nian)有超過1.7億(yi)個(ge)(ge)(ge)(ge)充(chong)(chong)電(dian)器(qi)(qi)被用(yong)于(yu)充(chong)(chong)電(dian)，根據推測，在(zai)此特別領域提(ti)(ti)升能(neng)效，每(mei)年(nian)將可(ke)節(jie)(jie)省2,200吉瓦時（即22億(yi)千瓦時）的電(dian)能(neng)。這(zhe)些電(dian)路足夠(gou)為35萬個(ge)(ge)(ge)(ge)家庭供電(dian)，相(xiang)當(dang)于(yu)為住宅/商(shang)業(ye)用(yong)電(dian)賬單每(mei)年(nian)節(jie)(jie)省3.06億(yi)美(mei)(mei)元。美(mei)(mei)國(guo)加(jia)州(zhou)(zhou)能(neng)源(yuan)委(wei)員會（CEC）實施(shi)的這(zhe)些能(neng)效規范(fan)要求手機(ji)、個(ge)(ge)(ge)(ge)人照護設備及電(dian)動工(gong)具(ju)所使用(yong)的所有消費(fei)類充(chong)(chong)電(dian)器(qi)(qi)在(zai)2013年(nian)2月(yue)前必須遵(zun)(zun)從，而(er)工(gong)業(ye)類充(chong)(chong)電(dian)器(qi)(qi)須在(zai)未來12個(ge)(ge)(ge)(ge)月(yue)內遵(zun)(zun)從。美(mei)(mei)國(guo)其他幾個(ge)(ge)(ge)(ge)州(zhou)(zhou)希望遵(zun)(zun)循加(jia)州(zhou)(zhou)降低(di)待(dai)機(ji)能(neng)耗(hao)限(xian)制(zhi)值的范(fan)例(li)。

　　圖2:電動工(gong)具所用的典型老(lao)式(shi)充電系統

　　圖2介紹了過去(qu)常用的(de)基(ji)本充(chong)(chong)電(dian)(dian)(dian)器系統電(dian)(dian)(dian)路圖。此特別案例使用鎳鉻(ge)（NiCd）電(dian)(dian)(dian)池(chi)(chi)來為(wei)電(dian)(dian)(dian)動工具(ju)充(chong)(chong)電(dian)(dian)(dian)。電(dian)(dian)(dian)池(chi)(chi)在1小(xiao)時內的(de)電(dian)(dian)(dian)量標為(wei)C.例如，以0.5 C的(de)充(chong)(chong)電(dian)(dian)(dian)速率來為(wei)額(e)定容量600 mAh的(de)電(dian)(dian)(dian)池(chi)(chi)充(chong)(chong)電(dian)(dian)(dian)，使用300 mA充(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流要經歷超過2小(xiao)時才能完全充(chong)(chong)滿電(dian)(dian)(dian)池(chi)(chi)。

　　圖2中的(de)電(dian)(dian)路能以0.1 C的(de)恒(heng)定充(chong)電(dian)(dian)速率。由于(yu)充(chong)電(dian)(dian)器(qi)的(de)60 Hz變壓器(qi)的(de)設計意圖是維(wei)持低成本，而(er)非(fei)提供高(gao)(gao)(gao)能效(xiao)等(deng)級(ji)，空載(zai)能耗通常將高(gao)(gao)(gao)于(yu)0.5 W,如此高(gao)(gao)(gao)的(de)空載(zai)能耗不(bu)再能夠(gou)令(ling)人接受。早期想法是使充(chong)電(dian)(dian)器(qi)能效(xiao)更高(gao)(gao)(gao)，但不(bu)注(zhu)意事實上充(chong)電(dian)(dian)后(hou)電(dian)(dian)路會持續(xu)無限(xian)期地浪費(fei)電(dian)(dian)能。這已(yi)經被證明是一(yi)種有(you)點誤導的(de)視(shi)角。

　　即便是(shi)當今市場(chang)上的(de)許(xu)多充(chong)電(dian)(dian)器(qi)，也仍(reng)然缺乏檢測電(dian)(dian)池(chi)是(shi)否(fou)完(wan)(wan)全充(chong)滿(man)的(de)能力，且因(yin)此在充(chong)電(dian)(dian)過(guo)程完(wan)(wan)成后仍(reng)然持續提供電(dian)(dian)能給電(dian)(dian)池(chi)，因(yin)而(er)浪費電(dian)(dian)能（釋放(fang)為熱量）。通過(guo)使用可(ke)以(yi)關閉(bi)完(wan)(wan)全充(chong)滿(man)之電(dian)(dian)池(chi)的(de)充(chong)電(dian)(dian)通道(dao)，電(dian)(dian)能就不會無(wu)謂地浪費，電(dian)(dian)池(chi)也不會置于損壞的(de)風險。

    提供低待(dai)機能(neng)耗工作的創(chuang)新方案

　　家庭中一(yi)項常(chang)見的(de)(de)(de)(de)(de)待機能耗源頭就是(shi)(shi)筆記(ji)(ji)本(ben)適(shi)(shi)(shi)配(pei)器(qi)(qi)(qi)。這些適(shi)(shi)(shi)配(pei)器(qi)(qi)(qi)相當多(duo)的(de)(de)(de)(de)(de)使用時(shi)間是(shi)(shi)在(zai)筆記(ji)(ji)本(ben)電(dian)腦(nao)斷開連接或關(guan)斷的(de)(de)(de)(de)(de)情(qing)況下在(zai)桌子底下度過(guo)的(de)(de)(de)(de)(de)。如今典型的(de)(de)(de)(de)(de)市售筆記(ji)(ji)本(ben)適(shi)(shi)(shi)配(pei)器(qi)(qi)(qi)在(zai)空載條(tiao)件下約消耗300 mW至(zhi)500 mW的(de)(de)(de)(de)(de)能耗。然而(er)，許多(duo)領先制(zhi)造(zao)商如今要求下一(yi)代筆記(ji)(ji)本(ben)適(shi)(shi)(shi)配(pei)器(qi)(qi)(qi)的(de)(de)(de)(de)(de)空載能耗限制(zhi)到低于30 mW,從而(er)使其產品(pin)與競爭產品(pin)區域開來(lai)。圖3顯示(shi)了65 W筆記(ji)(ji)本(ben)適(shi)(shi)(shi)配(pei)器(qi)(qi)(qi)用下一(yi)代充電(dian)系統的(de)(de)(de)(de)(de)簡(jian)化示(shi)例。此電(dian)路(lu)最重要的(de)(de)(de)(de)(de)元器(qi)(qi)(qi)件就是(shi)(shi)固定頻率電(dian)流模(mo)式控(kong)制(zhi)器(qi)(qi)(qi)IC及次級端開關(guan)電(dian)源（SMPS）控(kong)制(zhi)器(qi)(qi)(qi)IC.

　　圖3:帶(dai)空載檢測功(gong)能的先進充電(dian)電(dian)路簡化電(dian)路圖

　　這(zhe)示例中指定(ding)的(de)(de)(de)固定(ding)頻率電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)模式控制器(qi)（即安(an)森(sen)美半導體的(de)(de)(de)NCP1246）經過(guo)了專門優化，在空(kong)載(zai)及輕載(zai)條(tiao)件下消耗(hao)(hao)(hao)極低的(de)(de)(de)能(neng)(neng)耗(hao)(hao)(hao)。交流(liu)(liu)-直(zhi)流(liu)(liu)（AC-DC）電(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)空(kong)載(zai)條(tiao)件下輸(shu)入能(neng)(neng)耗(hao)(hao)(hao)的(de)(de)(de)其中一項主要(yao)來源(yuan)(yuan)是X2電(dian)(dian)(dian)(dian)(dian)(dian)容放(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)路。典型適(shi)配(pei)器(qi)包含(han)高壓(ya)(ya)X2電(dian)(dian)(dian)(dian)(dian)(dian)容，它連(lian)接至交流(liu)(liu)輸(shu)入端，作為電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)干擾（EMI）濾波器(qi)的(de)(de)(de)一部分。出于安(an)全(quan)(quan)原因，強制要(yao)求(qiu)此(ci)(ci)電(dian)(dian)(dian)(dian)(dian)(dian)容在從(cong)墻(qiang)上(shang)拔(ba)出適(shi)配(pei)器(qi)插(cha)頭后的(de)(de)(de)1秒(miao)時(shi)間內放(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)至安(an)全(quan)(quan)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)電(dian)(dian)(dian)(dian)(dian)(dian)平。否則，接觸交流(liu)(liu)插(cha)頭的(de)(de)(de)扁腳(jiao)（prong）就(jiu)面臨電(dian)(dian)(dian)(dian)(dian)(dian)擊的(de)(de)(de)危險。符合此(ci)(ci)要(yao)求(qiu)的(de)(de)(de)標準方(fang)法是使用一串與電(dian)(dian)(dian)(dian)(dian)(dian)容并聯的(de)(de)(de)高阻(zu)抗泄放(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)。當用于230 Vac應用時(shi)，這(zhe)恒(heng)定(ding)的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)型消耗(hao)(hao)(hao)源(yuan)(yuan)約消耗(hao)(hao)(hao)25 mW輸(shu)入能(neng)(neng)耗(hao)(hao)(hao)。當顧(gu)及到空(kong)載(zai)能(neng)(neng)耗(hao)(hao)(hao)時(shi)，這(zhe)25 mW就(jiu)變得相當大了。NCP1246解(jie)決此(ci)(ci)問題的(de)(de)(de)方(fang)法是加入帶有源(yuan)(yuan)放(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)路的(de)(de)(de)內置(zhi)交流(liu)(liu)線路檢測器(qi)。這(zhe)控制器(qi)在檢測到不再(zai)存在交流(liu)(liu)信(xin)號時(shi)，激活內置(zhi)開關來使電(dian)(dian)(dian)(dian)(dian)(dian)容放(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)。有了這(zhe)個(ge)功(gong)能(neng)(neng)，就(jiu)不再(zai)需要(yao)泄放(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)了，消除了恒(heng)定(ding)的(de)(de)(de)25 mW能(neng)(neng)耗(hao)(hao)(hao)源(yuan)(yuan)頭。

　　次級(ji)(ji)(ji)(ji)端開關(guan)電(dian)源控制器(qi)(qi)（即(ji)安森美半導(dao)體(ti)的(de)NCP4354）是NCP1246的(de)伴侶IC,能(neng)(neng)夠檢測空(kong)載條件(jian)，并使(shi)電(dian)源進入(ru)低能(neng)(neng)耗(hao)(hao)關(guan)閉模式(shi)。在(zai)關(guan)閉模式(shi)期間，初級(ji)(ji)(ji)(ji)端控制器(qi)(qi)停止工作(zuo)，能(neng)(neng)量由(you)輸(shu)(shu)(shu)出(chu)電(dian)容提(ti)供(gong)(gong)。適配器(qi)(qi)的(de)輸(shu)(shu)(shu)出(chu)電(dian)壓(ya)開始下(xia)降，因(yin)為(wei)初級(ji)(ji)(ji)(ji)端不再(zai)在(zai)存在(zai)開關(guan)工作(zuo)。這(zhe)并不構成什么問題(ti)，因(yin)為(wei)適配器(qi)(qi)在(zai)此模式(shi)下(xia)不再(zai)連接至(zhi)筆記(ji)本電(dian)腦。輸(shu)(shu)(shu)出(chu)電(dian)壓(ya)被允(yun)許下(xia)降至(zhi)某個可(ke)調節電(dian)平，直到NCP4354通知初級(ji)(ji)(ji)(ji)端重啟，重新(xin)為(wei)輸(shu)(shu)(shu)出(chu)電(dian)容充電(dian)并因(yin)此維持工作(zuo)。當(dang)適配器(qi)(qi)重新(xin)連接至(zhi)電(dian)池(chi)時(shi)，NCP4354控制器(qi)(qi)自動重啟初級(ji)(ji)(ji)(ji)端控制器(qi)(qi)。能(neng)(neng)僅(jin)以(yi)一(yi)顆光耦提(ti)供(gong)(gong)反饋控制及導(dao)通/關(guan)閉信號。當(dang)在(zai)此類電(dian)路(lu)中一(yi)起使(shi)用時(shi)，NCP1246和(he)NCP4354能(neng)(neng)夠采用美國規格的(de)交流(liu)主電(dian)源提(ti)供(gong)(gong)低于10 mW的(de)空(kong)載能(neng)(neng)耗(hao)(hao)，且在(zai)寬交流(liu)主電(dian)源電(dian)壓(ya)范圍(wei)下(xia)提(ti)供(gong)(gong)低于20 mW的(de)空(kong)載能(neng)(neng)耗(hao)(hao)。

　　圖4:65 W適配器電(dian)路圖

　　雖然許(xu)多消費(fei)電子OEM生(sheng)產高能(neng)效產品，但他們常常會對低能(neng)耗的(de)充電系(xi)(xi)統(tong)(tong)感到失望。如(ru)今已經出現重(zhong)要進(jin)展，電池充電器(qi)可以(yi)消耗更少電能(neng)，同(tong)時提供市(shi)場所(suo)(suo)要求的(de)高性能(neng)基準。諸如(ru)本文所(suo)(suo)介紹的(de)系(xi)(xi)統(tong)(tong)致力于滿足(zu)這些(xie)標準，并降低系(xi)(xi)統(tong)(tong)復雜(za)度、節(jie)省(sheng)珍(zhen)貴的(de)電路板空間及使物料單(dan)（BOM）成本受到控制(zhi)。