鋰電(dian)池的充電(dian)方法對(dui)于不同(tong)數(shu)量的電(dian)芯、電(dian)芯配置以(yi)及電(dian)源類(lei)型還是不同(tong)的。目前鋰電(dian)池充電(dian)主要有：線性,Buck(降壓)開(kai)關和 SEPIC(升壓與(yu)降壓開(kai)關)這(zhe)個三個方法，具(ju)體操作(zuo)如下：

1、鋰電池(chi)的線(xian)性充電方法(fa)

當充(chong)(chong)電(dian)器輸入電(dian)壓(ya)大(da)于全充(chong)(chong)滿(man)電(dian)芯加上充(chong)(chong)足浄空(kong)之后的開路電(dian)壓(ya)時,最好用線性(xing)方案,特別是1.0C快速充(chong)(chong)電(dian)電(dian)流不比1A大(da)太多時。

例(li)如:MP3播放器(qi)(qi)(qi)(qi)通(tong)常只有一(yi)個鋰電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)芯,容量從700到1500mAh不等,滿充(chong)(chong)開(kai)(kai)路電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓是4.2V。MP3播放機的(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源通(tong)常是AC/DC適(shi)配器(qi)(qi)(qi)(qi)或者(zhe)是USB接口,其輸(shu)出是規(gui)則的(de)5V;這時,線性方(fang)案的(de)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)器(qi)(qi)(qi)(qi)就是最簡單(dan)、最有效率(lv)的(de)方(fang)案。線性方(fang)案的(de)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)器(qi)(qi)(qi)(qi)應用例(li)舉-雙輸(shu)入Li+充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)器(qi)(qi)(qi)(qi)及智能電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源選擇器(qi)(qi)(qi)(qi)是雙輸(shu)入USB/AC適(shi)配器(qi)(qi)(qi)(qi)線性充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)器(qi)(qi)(qi)(qi),內置Smart Power Selector,用于(yu)由可充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)單(dan)節(jie)Li+電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)供電(dian)(dian)(dian)(dian)(dian)(dian)(dian)的(de)便攜式設備。該充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)器(qi)(qi)(qi)(qi)集成了電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)和(he)外(wai)部電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)和(he)切換負載所需的(de)全部功率(lv)開(kai)(kai)關,因此(ci)無需外(wai)部MOSFET:MAX8677A理想用于(yu)便

攜式(shi)設備(bei)(bei),例如智(zhi)能手機(ji)(ji)、PDA、便(bian)攜式(shi)多媒體播放(fang)器(qi)、GPS導(dao)航設備(bei)(bei)、數碼相機(ji)(ji)、以(yi)及數碼攝像機(ji)(ji)MAX8677A可以(yi)工作于獨立(li)的USB和AC適配器(qi)電(dian)源(yuan)輸(shu)(shu)入(ru)下或兩個(ge)輸(shu)(shu)入(ru)中(zhong)的任意一(yi)個(ge)輸(shu)(shu)入(ru)下:當連接(jie)外部(bu)電(dian)源(yuan)時(shi),智(zhi)能電(dian)源(yuan)選(xuan)擇器(qi)允許系統不連接(jie)電(dian)池或可以(yi)與深度放(fang)電(dian)電(dian)池連接(jie)。智(zhi)能電(dian)源(yuan)選(xuan)擇器(qi)自動將電(dian)池切換到系統負載,使用系統未利(li)用的輸(shu)(shu)入(ru)電(dian)源(yuan)部(bu)分為(wei)電(dian)池充(chong)電(dian),充(chong)分利(li)用有限的USB和適配器(qi)輸(shu)(shu)入(ru)電(dian)源(yuan)。所有需要的電(dian)流檢測

電(dian)(dian)(dian)路,包(bao)括集成(cheng)的功率開關,均集成(cheng)于片上。DC輸入電(dian)(dian)(dian)流限最高可調節至(zhi)2A,而DC和(he)(he)USB輸入均可支持(chi)(chi)100mA、500mA和(he)(he)USB掛起模式(shi)。充電(dian)(dian)(dian)電(dian)(dian)(dian)流可調節至(zhi)高達(da)1.5A,從而支持(chi)(chi)寬范圍的電(dian)(dian)(dian)池(chi)容(rong)性。MAX8677A的其(qi)他(ta)特(te)性包(bao)括熱調節、過壓保(bao)護、充電(dian)(dian)(dian)狀態和(he)(he)故障翰出(chu)、電(dian)(dian)(dian)源好監視(shi)、電(dian)(dian)(dian)池(chi)熱敏電(dian)(dian)(dian)阻(zu)監視(shi)、以及充電(dian)(dian)(dian)定(ding)時器。MAX8677A采用節省空間的、熱增強(qiang)型、4mmx4mm、24引腳的TQFN封裝,規定(ding)工作于擴展級溫度范圍(-40~+85℃)

2、鋰電(dian)池的Buck(降壓(ya))開關充電(dian)方法

當(dang)1.0C充(chong)(chong)電(dian)的(de)電(dian)流大于(yu)(yu)1A,或(huo)(huo)者輸入(ru)電(dian)壓(ya)比電(dian)芯的(de)全充(chong)(chong)滿(man)開路電(dian)壓(ya)高很多時,Buck或(huo)(huo)者降壓(ya)方案(an)就(jiu)是一個更(geng)好的(de)選擇。比如,在基于(yu)(yu)硬盤(pan)的(de)PMP中,通(tong)常使用(yong)單芯鋰離子電(dian)池,全充(chong)(chong)滿(man)開路電(dian)壓(ya)是4.2V,容量從(cong)1200到2400mAh不等(deng)。而現在PMP通(tong)常是用(yong)汽車套件(jian)來充(chong)(chong)電(dian),它(ta)的(de)輸出電(dian)壓(ya)在9V到16V之(zhi)間(jian)。在輸入(ru)電(dian)壓(ya)和鋰電(dian)池電(dian)壓(ya)之(zhi)間(jian)比較(jiao)高的(de)電(dian)壓(ya)差(最小4.8V)會讓線性方案(an)降低效率(lv)。這種低效率(lv),加上大于(yu)(yu)1.2A的(de)1C快(kuai)速充(chong)(chong)電(dian)電(dian)流,會產生(sheng)嚴重的(de)散熱問題。為(wei)避免這種情況(kuang),就(jiu)要采用(yong)Buck方案(an)

3、鋰電池(chi)的SEPIC(升壓與降壓)開關充(chong)電方法

在(zai)(zai)某些使(shi)用(yong)3個甚至4個鋰(li)離(li)子(zi)/聚合(he)物電(dian)芯串聯(lian)的設(she)備中，充電(dian)器的輸入(ru)電(dian)壓(ya)就(jiu)不總是大于電(dian)池(chi)電(dian)壓(ya)。比如，筆(bi)記(ji)本電(dian)腦使(shi)用(yong)3芯鋰(li)離(li)子(zi)電(dian)池(chi)組，滿(man)充開路電(dian)壓(ya)是12.6V(4.2V×3)，容量從(cong)1800mAh到3600mAh。輸入(ru)電(dian)源要么是輸出(chu)電(dian)壓(ya)16V的AC/DC適配器，要么是汽車套件，輸出(chu)電(dian)壓(ya)在(zai)(zai)9V到16V之(zhi)間(jian)。很顯然地，線性(xing)和Buck方(fang)案都不能為這(zhe)組電(dian)池(chi)組充電(dian)。這(zhe)就(jiu)要用(yong)上(shang)SEPIC方(fang)案，它能在(zai)(zai)輸出(chu)電(dian)壓(ya)高于電(dian)池(chi)電(dian)壓(ya)時工作(zuo)，也能在(zai)(zai)輸出(chu)電(dian)壓(ya)低于電(dian)池(chi)時工作(zuo)。