現在，大多數手持式設備都采用了兩種電池充電器，一種(zhong)(zhong)是(shi)線性充(chong)電(dian)器(qi)(qi)，另一種(zhong)(zhong)是(shi)開(kai)關充(chong)電(dian)器(qi)(qi)。線性充(chong)電(dian)器(qi)(qi)已有(you)(you)(you)較長的歷史，充(chong)電(dian)方式比較簡單有(you)(you)(you)效(xiao)，噪聲很小(xiao)，且沒有(you)(you)(you)太多外(wai)部元件。但是(shi)，隨(sui)著便(bian)攜式設備(bei)越(yue)來越(yue)復雜，新功(gong)能層出不窮，高容量電(dian)池的需(xu)求就更加(jia)強烈。線形(xing)充(chong)電(dian)器(qi)(qi)的缺點是(shi)功(gong)耗太大，特別是(shi)在設備(bei)邊(bian)充(chong)電(dian)邊(bian)使用的時候尤為明顯，此時產(chan)生(sheng)的熱量可能損壞系統或電(dian)池。

　　可供選(xuan)擇的(de)有開關(guan)充電器或開關(guan)模(mo)式電池(chi)充電器IC，它可以使用盡(jin)可能(neng)少(shao)的(de)電量，為電池(chi)提供更(geng)高的(de)電流。從(cong)過往經(jing)驗來(lai)看，這類IC一(yi)般會(hui)存在一(yi)些噪聲問題。此(ci)外，前幾代的(de)開關(guan)式充電器還需要一(yi)些外部元件。

　　然而，開關式電池拓撲結構的(de)優勢也(ye)是顯而易見。這些優勢包括(kuo)更(geng)高(gao)的(de)效率(lv)和更(geng)低的(de)功耗(hao)，還(huan)有更(geng)短的(de)充(chong)電時(shi)間。此類裝置(zhi)還(huan)能利用(yong)較(jiao)(jiao)高(gao)的(de)輸(shu)入電壓充(chong)電，使用(yong)成本較(jiao)(jiao)低的(de)非穩壓適配器。還(huan)可以(yi)提高(gao)來自限流電流源的(de)充(chong)電電流。

　　開(kai)(kai)關(guan)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)器(qi)(qi)通常在(zai)輕負載運行時會產生(sheng)噪(zao)聲(sheng)，特別是在(zai)預處(chu)(chu)理過程(cheng)中(zhong)。隨著噪(zao)聲(sheng)的(de)減(jian)少，開(kai)(kai)關(guan)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)器(qi)(qi)會進入脈沖跳躍(pulse skipping)模(mo)(mo)(mo)式(shi)運行。在(zai)脈沖跳躍模(mo)(mo)(mo)式(shi)中(zhong)，PWM頻率異步(bu)變化。目(mu)前開(kai)(kai)發的(de)電(dian)(dian)(dian)(dian)(dian)池(chi)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)器(qi)(qi)IC，可以在(zai)使用(yong)開(kai)(kai)關(guan)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)器(qi)(qi)時提供高充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)，且對系統的(de)熱(re)影響(xiang)非常小，而在(zai)低電(dian)(dian)(dian)(dian)(dian)流(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)模(mo)(mo)(mo)式(shi)下切換到(dao)線性(xing)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)器(qi)(qi)，以減(jian)少噪(zao)聲(sheng)。這(zhe)種可提供線性(xing)模(mo)(mo)(mo)式(shi)的(de)PWM開(kai)(kai)關(guan)模(mo)(mo)(mo)式(shi)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)器(qi)(qi)可以在(zai)全恒(heng)(heng)流(liu)(快(kuai)速(su)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian))條件(jian)下實現(xian)高效(xiao)率。開(kai)(kai)關(guan)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)器(qi)(qi)可利用(yong)PWM開(kai)(kai)關(guan)穩壓(ya)器(qi)(qi)控制高達2A的(de)恒(heng)(heng)流(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)。當電(dian)(dian)(dian)(dian)(dian)池(chi)處(chu)(chu)于(yu)預處(chu)(chu)理過程(cheng)以及恒(heng)(heng)壓(ya)尖(jian)峰(taper)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)模(mo)(mo)(mo)式(shi)快(kuai)結束(shu)時，設備(bei)會自動轉(zhuan)換到(dao)線形模(mo)(mo)(mo)式(shi)，以降低噪(zao)聲(sheng)，并利用(yong)開(kai)(kai)關(guan)模(mo)(mo)(mo)式(shi)加(jia)快(kuai)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)。一旦(dan)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)值低于(yu)300mA，線性(xing)模(mo)(mo)(mo)式(shi)會完全啟動，開(kai)(kai)關(guan)轉(zhuan)換器(qi)(qi)產生(sheng)的(de)噪(zao)聲(sheng)就會消除(chu)。

　　 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(fang)案，它的(de)充(chong)電電流(liu)高達(da)1A，具備(bei)先進的(de)電充(chong)滿顯示功能，可(ke)以實現全程充(chong)電系統監控。符(fu)合(he)USB標準的(de)100mA/500mA充(chong)電電流(liu)設置(zhi)有助于實現可(ke)編(bian)程預充(chong)電和快速充(chong)電。許多產(chan)品還具備(bei)電池(chi)溫度監測(ce)功能，以確保安全充(chong)電。

　　Intersil等公(gong)司(si)正在(zai)開(kai)發新一代充(chong)電(dian)器IC技(ji)術。這些完全集成的(de)解決(jue)方案非常適(shi)(shi)合緊湊型應(ying)用，還能為高功(gong)率(lv)應(ying)用提供充(chong)電(dian)控制功(gong)能。目前，充(chong)電(dian)電(dian)壓精度能達到(dao)0.5%，較前幾年的(de)1%有很大改善。開(kai)關頻率(lv)可達3MHz，而(er)且新型開(kai)關充(chong)電(dian)器可提供高達2A的(de)充(chong)電(dian)電(dian)流，最新的(de)一個應(ying)用實例是ISL9220，它適(shi)(shi)用于一節(jie)(jie)和兩節(jie)(jie)鋰離子電(dian)池應(ying)用。

　　另(ling)外，新設計還(huan)可以(yi)限制泄(xie)漏(lou)，目(mu)前在沒有(you)加上輸入(ru)功率(lv)時，典(dian)型的(de)泄(xie)漏(lou)電流已低于0.5uA。而且這些改進還(huan)可以(yi)用于更(geng)小的(de)封(feng)裝，如(ru)4mm×4mm QFN或2mm×2mm CSP，以(yi)節省手持式設備的(de)設計空間。

　　最新的電池充電器IC還能夠監(jian)視輸入(ru)電(dian)壓、電(dian)池電(dian)壓和充電(dian)電(dian)流。當三個參數中任意一個超出特定限(xian)額時，該IC就(jiu)會關(guan)閉內部(bu)N溝道MOSFET，使充電(dian)系統停止(zhi)對電(dian)池充電(dian)。利(li)用(yong)這(zhe)些(xie)重要的(de)器件可以靈(ling)活地(di)提高效(xiao)率，這(zhe)對持(chi)續(xu)增長、功能不斷(duan)擴充的(de)移動、手持(chi)式產品(pin)是(shi)至關(guan)重要的(de)。