現在，大多數手持式設備都采用了兩種電池充電器，一種是(shi)(shi)線性(xing)充電器，另一種是(shi)(shi)開(kai)關充電器。線性(xing)充電器已有(you)較(jiao)長的歷史，充電方式比(bi)較(jiao)簡(jian)單(dan)有(you)效，噪聲很(hen)小，且沒有(you)太多外(wai)部元件。但是(shi)(shi)，隨著便攜式設備越來越復雜，新(xin)功(gong)能層出不窮，高容量電池(chi)的需(xu)求就更加強烈。線形充電器的缺點(dian)是(shi)(shi)功(gong)耗太大，特別(bie)是(shi)(shi)在設備邊充電邊使(shi)用(yong)的時(shi)候尤為明(ming)顯，此時(shi)產生的熱量可能損壞系統或(huo)電池(chi)。

　　可(ke)供(gong)選擇的有開關充電(dian)(dian)器或開關模(mo)式電(dian)(dian)池(chi)充電(dian)(dian)器IC，它可(ke)以使用盡可(ke)能少的電(dian)(dian)量，為(wei)電(dian)(dian)池(chi)提供(gong)更高的電(dian)(dian)流(liu)。從過往經驗(yan)來看，這類IC一(yi)般(ban)會(hui)存在一(yi)些(xie)噪(zao)聲問題(ti)。此(ci)外，前幾代的開關式充電(dian)(dian)器還需要一(yi)些(xie)外部元(yuan)件。

　　然而(er)，開關式(shi)電池(chi)拓撲(pu)結構(gou)的優(you)(you)勢(shi)也是顯而(er)易見。這些優(you)(you)勢(shi)包括更高(gao)(gao)的效率和更低的功耗，還(huan)有更短的充(chong)電時間。此類裝(zhuang)置還(huan)能利用較(jiao)高(gao)(gao)的輸(shu)入電壓充(chong)電，使用成本較(jiao)低的非(fei)穩壓適(shi)配(pei)器。還(huan)可以提高(gao)(gao)來(lai)自限(xian)流(liu)電流(liu)源的充(chong)電電流(liu)。

　　開(kai)關(guan)充(chong)(chong)(chong)電(dian)(dian)器(qi)(qi)通常在(zai)(zai)(zai)(zai)輕負載運(yun)(yun)行時會(hui)產(chan)生(sheng)噪(zao)聲(sheng)，特別是在(zai)(zai)(zai)(zai)預(yu)處(chu)理過(guo)程中。隨著噪(zao)聲(sheng)的(de)減(jian)少，開(kai)關(guan)充(chong)(chong)(chong)電(dian)(dian)器(qi)(qi)會(hui)進入脈沖跳(tiao)躍(pulse skipping)模(mo)式(shi)運(yun)(yun)行。在(zai)(zai)(zai)(zai)脈沖跳(tiao)躍模(mo)式(shi)中，PWM頻(pin)率異步變化。目前開(kai)發的(de)電(dian)(dian)池(chi)充(chong)(chong)(chong)電(dian)(dian)器(qi)(qi)IC，可(ke)(ke)(ke)以(yi)(yi)在(zai)(zai)(zai)(zai)使用開(kai)關(guan)充(chong)(chong)(chong)電(dian)(dian)器(qi)(qi)時提供(gong)高(gao)充(chong)(chong)(chong)電(dian)(dian)電(dian)(dian)流，且對系統的(de)熱(re)影(ying)響(xiang)非(fei)常小，而在(zai)(zai)(zai)(zai)低電(dian)(dian)流充(chong)(chong)(chong)電(dian)(dian)模(mo)式(shi)下(xia)切換(huan)到線(xian)性充(chong)(chong)(chong)電(dian)(dian)器(qi)(qi)，以(yi)(yi)減(jian)少噪(zao)聲(sheng)。這種(zhong)可(ke)(ke)(ke)提供(gong)線(xian)性模(mo)式(shi)的(de)PWM開(kai)關(guan)模(mo)式(shi)充(chong)(chong)(chong)電(dian)(dian)器(qi)(qi)可(ke)(ke)(ke)以(yi)(yi)在(zai)(zai)(zai)(zai)全恒(heng)流(快速充(chong)(chong)(chong)電(dian)(dian))條件(jian)下(xia)實現高(gao)效(xiao)率。開(kai)關(guan)充(chong)(chong)(chong)電(dian)(dian)器(qi)(qi)可(ke)(ke)(ke)利(li)(li)用PWM開(kai)關(guan)穩(wen)壓器(qi)(qi)控制(zhi)高(gao)達(da)2A的(de)恒(heng)流充(chong)(chong)(chong)電(dian)(dian)。當電(dian)(dian)池(chi)處(chu)于(yu)預(yu)處(chu)理過(guo)程以(yi)(yi)及恒(heng)壓尖峰(taper)充(chong)(chong)(chong)電(dian)(dian)模(mo)式(shi)快結束時，設備會(hui)自動轉(zhuan)換(huan)到線(xian)形模(mo)式(shi)，以(yi)(yi)降(jiang)低噪(zao)聲(sheng)，并利(li)(li)用開(kai)關(guan)模(mo)式(shi)加快充(chong)(chong)(chong)電(dian)(dian)。一旦充(chong)(chong)(chong)電(dian)(dian)電(dian)(dian)流值(zhi)低于(yu)300mA，線(xian)性模(mo)式(shi)會(hui)完全啟動，開(kai)關(guan)轉(zhuan)換(huan)器(qi)(qi)產(chan)生(sheng)的(de)噪(zao)聲(sheng)就會(hui)消除。

　　 但是，現在充電技術有了進一步的發展。例如，一種用于新型手持式設備的單節鋰離子/聚合物電池充電器解決方案，它(ta)的(de)充(chong)電(dian)電(dian)流高(gao)達1A，具備(bei)先(xian)進的(de)電(dian)充(chong)滿顯示(shi)功能(neng)，可以實現(xian)全程充(chong)電(dian)系統監控。符(fu)合USB標準的(de)100mA/500mA充(chong)電(dian)電(dian)流設置有助(zhu)于實現(xian)可編(bian)程預充(chong)電(dian)和快速充(chong)電(dian)。許多產品還具備(bei)電(dian)池溫度監測(ce)功能(neng)，以確保安全充(chong)電(dian)。

　　Intersil等公司(si)正(zheng)在開(kai)發新(xin)一代充(chong)電(dian)器(qi)IC技術。這些(xie)完全(quan)集成的(de)解決方案非常適合緊湊(cou)型應用(yong)(yong)，還能為高(gao)功(gong)率應用(yong)(yong)提供(gong)充(chong)電(dian)控制功(gong)能。目前，充(chong)電(dian)電(dian)壓精度能達到0.5%，較前幾年(nian)的(de)1%有很大改善。開(kai)關(guan)頻率可達3MHz，而且新(xin)型開(kai)關(guan)充(chong)電(dian)器(qi)可提供(gong)高(gao)達2A的(de)充(chong)電(dian)電(dian)流，最新(xin)的(de)一個應用(yong)(yong)實例是ISL9220，它適用(yong)(yong)于一節和兩(liang)節鋰離子電(dian)池(chi)應用(yong)(yong)。

　　另外，新設(she)計(ji)還可以(yi)限制泄(xie)漏，目前在(zai)沒(mei)有加上輸入(ru)功率時，典型的泄(xie)漏電流(liu)已低于(yu)0.5uA。而且這些改(gai)進還可以(yi)用(yong)于(yu)更小的封(feng)裝，如4mm×4mm QFN或2mm×2mm CSP，以(yi)節省手持式(shi)設(she)備(bei)的設(she)計(ji)空間。

　　最新的電池充電器IC還(huan)能夠監(jian)視輸入電(dian)(dian)(dian)(dian)壓、電(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)壓和充電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流。當(dang)三個(ge)參數中任意一個(ge)超(chao)出特(te)定限額時，該IC就會關閉內部N溝道MOSFET，使(shi)充電(dian)(dian)(dian)(dian)系統停止對電(dian)(dian)(dian)(dian)池(chi)充電(dian)(dian)(dian)(dian)。利用這些(xie)重要(yao)的器(qi)件(jian)可以靈活地提高效率，這對持續(xu)增長、功能不斷(duan)擴充的移動、手持式產品是至關重要(yao)的。