現在，大多數手持式設備都采用了兩種電池充電器，一(yi)種(zhong)是(shi)(shi)線(xian)性充電器(qi)，另一(yi)種(zhong)是(shi)(shi)開關(guan)充電器(qi)。線(xian)性充電器(qi)已(yi)有(you)較長的(de)歷史，充電方(fang)式比較簡單有(you)效，噪聲(sheng)很小，且沒(mei)有(you)太(tai)多外部(bu)元件。但是(shi)(shi)，隨(sui)著便攜(xie)式設備(bei)越(yue)來越(yue)復雜(za)，新功能層出不窮，高容量(liang)(liang)電池(chi)的(de)需求就更(geng)加(jia)強烈(lie)。線(xian)形(xing)充電器(qi)的(de)缺點是(shi)(shi)功耗太(tai)大，特別(bie)是(shi)(shi)在設備(bei)邊充電邊使用的(de)時(shi)候尤為(wei)明(ming)顯，此時(shi)產生的(de)熱量(liang)(liang)可能損(sun)壞系(xi)統(tong)或電池(chi)。

　　可供選(xuan)擇的(de)(de)有(you)開關充(chong)電器或(huo)開關模式電池(chi)充(chong)電器IC，它可以使用盡可能少的(de)(de)電量，為電池(chi)提供更高的(de)(de)電流。從過往經驗來看，這類IC一(yi)(yi)般會存在一(yi)(yi)些噪聲問題。此外(wai)，前(qian)幾代的(de)(de)開關式充(chong)電器還需要一(yi)(yi)些外(wai)部元件。

　　然(ran)而(er)，開關式電池拓撲(pu)結構的(de)(de)優勢也是顯而(er)易見(jian)。這些(xie)優勢包括更高的(de)(de)效(xiao)率和更低的(de)(de)功耗，還(huan)(huan)有更短的(de)(de)充(chong)電時(shi)間。此類(lei)裝置還(huan)(huan)能(neng)利(li)用較高的(de)(de)輸(shu)入(ru)電壓充(chong)電，使(shi)用成本較低的(de)(de)非穩壓適配器。還(huan)(huan)可(ke)以提(ti)高來自限流(liu)(liu)電流(liu)(liu)源的(de)(de)充(chong)電電流(liu)(liu)。

　　開(kai)(kai)(kai)(kai)關(guan)(guan)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)器(qi)(qi)通常在(zai)輕(qing)負載(zai)運(yun)行時會(hui)(hui)產(chan)生(sheng)噪聲(sheng)，特別是在(zai)預(yu)處理過(guo)程中(zhong)。隨著(zhu)噪聲(sheng)的(de)(de)(de)減(jian)少，開(kai)(kai)(kai)(kai)關(guan)(guan)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)器(qi)(qi)會(hui)(hui)進入脈沖跳躍(pulse skipping)模(mo)(mo)(mo)式(shi)(shi)運(yun)行。在(zai)脈沖跳躍模(mo)(mo)(mo)式(shi)(shi)中(zhong)，PWM頻率異步變化(hua)。目前開(kai)(kai)(kai)(kai)發的(de)(de)(de)電(dian)(dian)(dian)池(chi)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)器(qi)(qi)IC，可(ke)以(yi)在(zai)使用開(kai)(kai)(kai)(kai)關(guan)(guan)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)器(qi)(qi)時提(ti)供高充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)(liu)，且對系統的(de)(de)(de)熱影響(xiang)非(fei)常小，而在(zai)低電(dian)(dian)(dian)流(liu)(liu)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)模(mo)(mo)(mo)式(shi)(shi)下切(qie)換到線性充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)器(qi)(qi)，以(yi)減(jian)少噪聲(sheng)。這(zhe)種(zhong)可(ke)提(ti)供線性模(mo)(mo)(mo)式(shi)(shi)的(de)(de)(de)PWM開(kai)(kai)(kai)(kai)關(guan)(guan)模(mo)(mo)(mo)式(shi)(shi)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)器(qi)(qi)可(ke)以(yi)在(zai)全(quan)恒(heng)流(liu)(liu)(快(kuai)速充(chong)(chong)(chong)(chong)電(dian)(dian)(dian))條(tiao)件下實現高效率。開(kai)(kai)(kai)(kai)關(guan)(guan)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)器(qi)(qi)可(ke)利用PWM開(kai)(kai)(kai)(kai)關(guan)(guan)穩壓(ya)器(qi)(qi)控制高達2A的(de)(de)(de)恒(heng)流(liu)(liu)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)。當電(dian)(dian)(dian)池(chi)處于預(yu)處理過(guo)程以(yi)及恒(heng)壓(ya)尖(jian)峰(taper)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)模(mo)(mo)(mo)式(shi)(shi)快(kuai)結束時，設備會(hui)(hui)自動(dong)(dong)轉換到線形模(mo)(mo)(mo)式(shi)(shi)，以(yi)降低噪聲(sheng)，并利用開(kai)(kai)(kai)(kai)關(guan)(guan)模(mo)(mo)(mo)式(shi)(shi)加快(kuai)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)。一旦(dan)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)(liu)值低于300mA，線性模(mo)(mo)(mo)式(shi)(shi)會(hui)(hui)完全(quan)啟動(dong)(dong)，開(kai)(kai)(kai)(kai)關(guan)(guan)轉換器(qi)(qi)產(chan)生(sheng)的(de)(de)(de)噪聲(sheng)就會(hui)(hui)消(xiao)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，它的充(chong)電(dian)(dian)電(dian)(dian)流(liu)高達1A，具(ju)備先進的電(dian)(dian)充(chong)滿顯示功能(neng)，可以實現全程(cheng)充(chong)電(dian)(dian)系統監(jian)控。符合(he)USB標準的100mA/500mA充(chong)電(dian)(dian)電(dian)(dian)流(liu)設(she)置有助(zhu)于實現可編程(cheng)預充(chong)電(dian)(dian)和快速充(chong)電(dian)(dian)。許多產品還具(ju)備電(dian)(dian)池溫度監(jian)測(ce)功能(neng)，以確(que)保安全充(chong)電(dian)(dian)。

　　Intersil等公司正在開發新一(yi)代充電(dian)(dian)器(qi)IC技術。這些完全集(ji)成的解決方案非常適合緊湊(cou)型應用，還能(neng)為高功(gong)率應用提供充電(dian)(dian)控(kong)制功(gong)能(neng)。目前，充電(dian)(dian)電(dian)(dian)壓精度能(neng)達到0.5%，較(jiao)前幾年的1%有很(hen)大改善。開關(guan)頻率可達3MHz，而且新型開關(guan)充電(dian)(dian)器(qi)可提供高達2A的充電(dian)(dian)電(dian)(dian)流，最新的一(yi)個(ge)應用實例是ISL9220，它適用于一(yi)節和兩節鋰離(li)子電(dian)(dian)池應用。

　　另(ling)外(wai)，新(xin)設計還可(ke)以限制(zhi)泄(xie)漏(lou)，目前在沒(mei)有(you)加上輸(shu)入(ru)功率(lv)時(shi)，典型的泄(xie)漏(lou)電流(liu)已低(di)于(yu)0.5uA。而且這些改(gai)進還可(ke)以用于(yu)更小(xiao)的封裝(zhuang)，如4mm×4mm QFN或2mm×2mm CSP，以節省手持式設備(bei)的設計空間。

　　最新的電池充電器IC還能夠監視輸(shu)入電(dian)(dian)壓、電(dian)(dian)池(chi)電(dian)(dian)壓和充電(dian)(dian)電(dian)(dian)流。當三個參數中(zhong)任意一個超出特定限額時，該IC就會關(guan)閉內(nei)部(bu)N溝道MOSFET，使充電(dian)(dian)系(xi)統停止(zhi)對電(dian)(dian)池(chi)充電(dian)(dian)。利(li)用(yong)這(zhe)些重要(yao)的器件可(ke)以靈活(huo)地提高(gao)效率，這(zhe)對持續增長、功能不斷擴(kuo)充的移動(dong)、手持式產品是至關(guan)重要(yao)的。