如今的(de)便(bian)攜式(shi)電(dian)(dian)(dian)(dian)子(zi)備(bei)中(zhong)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)技(ji)術(shu)包括電(dian)(dian)(dian)(dian)量檢測(ce)算法、電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)充電(dian)(dian)(dian)(dian)算法與電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)充電(dian)(dian)(dian)(dian)技(ji)術(shu)等(deng)(deng)幾個(ge)方面。眾(zhong)所周知(zhi),充電(dian)(dian)(dian)(dian)式(shi)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)化學反(fan)應有(you)鎳鎘、鎳氫(qing)、鋰離(li)子(zi)和鋰聚(ju)合物(wu)4種程(cheng)式(shi),作為(wei)便(bian)攜式(shi)電(dian)(dian)(dian)(dian)子(zi)設備(bei)來說(shuo),雖然這(zhe)4種電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)程(cheng)式(shi)各有(you)特點,但從能量密度與安全性角度的(de)發展與實(shi)踐可知(zhi), 鋰離(li)子(zi)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)和鋰聚(ju)合物(wu)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)的(de)優(you)勢(shi)己(ji)成為(wei)小型長運(yun)行時間的(de)設備(bei)的(de)理想之(zhi)選，比如筆記本電(dian)(dian)(dian)(dian)腦以及基于硬盤的(de)PMP等(deng)(deng).對便(bian)攜式(shi)電(dian)(dian)(dian)(dian)子(zi)備(bei)工程(cheng)師來說(shuo)，正確選擇與應用好便(bian)攜式(shi)電(dian)(dian)(dian)(dian)子(zi)備(bei)中(zhong)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)技(ji)術(shu)至關重要,值(zhi)此本文(wen)將(jiang)對此作研討(tao),并(bing)作應用舉例分析.

1、關于細流充(chong)電(dian)、快速充(chong)電(dian)和穩(wen)定充(chong)電(dian)的(de)電(dian)池(chi)充(chong)電(dian)算(suan)法

根據最(zui)終應用的(de)能(neng)量需求，一個電(dian)(dian)池組可能(neng)包(bao)含最(zui)多4個鋰離子或(huo)(huo)鋰聚合(he)物電(dian)(dian)池芯(xin),其配置(zhi)可有(you)多種變化，同(tong)時帶有(you)一個主流的(de)電(dian)(dian)源適配器：直接(jie)的(de)適配器、USB接(jie)口(kou)或(huo)(huo)汽車充電(dian)(dian)器。除去電(dian)(dian)芯(xin)數(shu)量、電(dian)(dian)芯(xin)的(de)配置(zhi)或(huo)(huo)電(dian)(dian)源適配器類(lei)型上的(de)差別，這些(xie)電(dian)(dian)池組都有(you)同(tong)樣(yang)的(de)充電(dian)(dian)特性。因(yin)此它們的(de)充電(dian)(dian)算(suan)法也一樣(yang)。鋰離子與鋰聚合(he)物電(dian)(dian)池最(zui)好的(de)充電(dian)(dian)算(suan)法可以分為3個階段：細(xi)流充電(dian)(dian)、快速充電(dian)(dian)和(he)穩定充電(dian)(dian)。

*細流充電.用于對深度放電的電芯進行充電。當電芯電壓在低于大約2.8V時，用一個恒定的0.1C的電流為它充電。
*快速充電.電芯電壓超過細流充電的門檻時，提高充電電流進行快速充電。快速充電電流應低于1.0C。
*穩定(ding)(ding)(ding)電(dian)(dian)(dian)壓。在快速充(chong)(chong)電(dian)(dian)(dian)過程中，一(yi)(yi)旦電(dian)(dian)(dian)芯電(dian)(dian)(dian)壓達(da)到4.2V，穩定(ding)(ding)(ding)電(dian)(dian)(dian)壓階段(duan)就開始了。這時可(ke)通過最小充(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流或(huo)定(ding)(ding)(ding)時器或(huo)這兩者的(de)聯合來中斷(duan)充(chong)(chong)電(dian)(dian)(dian).當最小電(dian)(dian)(dian)流低于(yu)大(da)約(yue)0.07C時，可(ke)中斷(duan)充(chong)(chong)電(dian)(dian)(dian)。定(ding)(ding)(ding)時器則(ze)要靠一(yi)(yi)個(ge)預設(she)的(de)定(ding)(ding)(ding)時器來觸發中斷(duan)。

高級的電池充電器通(tong)常帶(dai)有(you)(you)附加(jia)的(de)(de)安全功(gong)能。比(bi)如(ru)(ru)，如(ru)(ru)果電芯溫度超出給定窗(chuang)口，通(tong)常是0℃--45℃，充(chong)電就會(hui)暫停。除去(qu)某些非(fei)常低端(duan)的(de)(de)設備，現在市面(mian)上的(de)(de)鋰(li)離(li)子／鋰(li)聚合物(wu)電池充(chong)電方案都集成或是帶(dai)有(you)(you)外置的(de)(de)元件，以便按照充(chong)電特性進行(xing)充(chong)電，這(zhe)不光是為了(le)取得(de)更佳充(chong)電效果，同(tong)時也是為了(le)安全。

2、鋰離子(zi)/聚合物電池(chi)充電方案

鋰離子/聚合物(wu)電(dian)池的充(chong)電(dian)方案(an)對于不(bu)同數(shu)量的電(dian)芯、電(dian)芯配置以及(ji)電(dian)源類型還是(shi)不(bu)同的。目前主要有(you)3種主要的充(chong)電(dian)方案(an)：線性，Buck(降(jiang)壓(ya))開關(guan)和SEPIC(升壓(ya)與降(jiang)壓(ya))開關(guan)。

2.1線性方案

當充(chong)電(dian)(dian)器(qi)輸(shu)入電(dian)(dian)壓(ya)大于全充(chong)滿電(dian)(dian)芯加上充(chong)足(zu)凈空(kong)之后的(de)開路(lu)電(dian)(dian)壓(ya)時，最(zui)好(hao)用線(xian)(xian)性(xing)(xing)(xing)方(fang)(fang)案，特別(bie)是(shi)(shi)1.0C快速充(chong)電(dian)(dian)電(dian)(dian)流不比(bi)1A大太多時。比(bi)如，MP3播放器(qi)通(tong)常(chang)只有(you)一個電(dian)(dian)芯，容量從700到1500mAh不等，滿充(chong)開路(lu)電(dian)(dian)壓(ya)是(shi)(shi)4.2V。MP3播放機的(de)電(dian)(dian)源(yuan)通(tong)常(chang)是(shi)(shi)AC／DC適配器(qi)或者是(shi)(shi)USB接口，其(qi)輸(shu)出是(shi)(shi)規則的(de)5V；這(zhe)時，線(xian)(xian)性(xing)(xing)(xing)方(fang)(fang)案的(de)充(chong)電(dian)(dian)器(qi)就是(shi)(shi)最(zui)簡單(dan)、最(zui)有(you)效率(lv)的(de)方(fang)(fang)案。圖2所示為鋰離子/聚(ju)合(he)物電(dian)(dian)池充(chong)電(dian)(dian)方(fang)(fang)案線(xian)(xian)性(xing)(xing)(xing)方(fang)(fang)案,基本結構和線(xian)(xian)性(xing)(xing)(xing)電(dian)(dian)壓(ya)規整器(qi)一樣。

*線性方案的(de)充(chong)(chong)電(dian)(dian)(dian)(dian)器(qi)應用(yong)例(li)舉-雙(shuang)輸入Li+充(chong)(chong)電(dian)(dian)(dian)(dian)器(qi)及智能電(dian)(dian)(dian)(dian)源(yuan)(yuan)選擇器(qi)MAX8677A。MAX8677A是雙(shuang)輸入USB/AC適配器(qi)線性充(chong)(chong)電(dian)(dian)(dian)(dian)器(qi)，內置Smart Power Selector，用(yong)于由可充(chong)(chong)電(dian)(dian)(dian)(dian)單節Li+電(dian)(dian)(dian)(dian)池(chi)(chi)供電(dian)(dian)(dian)(dian)的(de)便攜(xie)式(shi)(shi)設備。該充(chong)(chong)電(dian)(dian)(dian)(dian)器(qi)集成(cheng)了電(dian)(dian)(dian)(dian)池(chi)(chi)和(he)外部(bu)電(dian)(dian)(dian)(dian)源(yuan)(yuan)充(chong)(chong)電(dian)(dian)(dian)(dian)和(he)切換負(fu)載所需(xu)的(de)全部(bu)功率開關，因此無需(xu)外部(bu) MOSFET。MAX8677A理想用(yong)于便攜(xie)式(shi)(shi)設備，例(li)如(ru)智能手(shou)機、PDA、便攜(xie)式(shi)(shi)多媒體播放器(qi)、GPS導(dao)航設備、數(shu)碼相機、以及數(shu)碼攝像機。

MAX8677A可以工作于獨立的USB和AC適配器電源輸入下或兩個輸入中的任意一個輸入下。當連接外部電源時，智能電源選擇器允許系統不連接電池或可以與深度放電電池連接。智能充電器電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)選擇器(qi)自動將電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)切換到系(xi)統負載，使用系(xi)統未利用的(de)(de)輸(shu)入電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)部(bu)分為電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，充分利用有限的(de)(de)USB和(he)(he)適配器(qi)輸(shu)入電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)。所有需要(yao)的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流檢測(ce)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路，包(bao)括(kuo)集成的(de)(de)功率開(kai)關(guan)，均集成于(yu)片上。DC輸(shu)入電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流限最高可(ke)調(diao)(diao)節(jie)(jie)(jie)至2A，而DC和(he)(he)USB輸(shu)入均可(ke)支持(chi)100mA、500mA、和(he)(he)USB掛(gua)起模(mo)式。充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流可(ke)調(diao)(diao)節(jie)(jie)(jie)至高達1.5A，從而支持(chi) 寬范圍的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)容(rong)性(xing)。MAX8677A的(de)(de)其他特性(xing)包(bao)括(kuo)熱(re)(re)調(diao)(diao)節(jie)(jie)(jie)、過壓保護、充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)狀態和(he)(he)故(gu)障輸(shu)出、電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)好(hao)監視、電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)熱(re)(re)敏(min)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻監視、以及充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)定時器(qi)。MAX8677A采用節(jie)(jie)(jie)省空(kong)間的(de)(de)、熱(re)(re)增強型(xing)、4mm×4mm、24引腳的(de)(de)TQFN封裝(zhuang)，規(gui)定工(gong)作(zuo)于(yu)擴展級溫(wen)度范圍(-40～+85℃)。

2.2 Buck(降壓)開關方(fang)案

當1.0C充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)的(de)電(dian)(dian)(dian)(dian)(dian)流大于1A，或者輸(shu)(shu)(shu)入電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)比電(dian)(dian)(dian)(dian)(dian)芯(xin)的(de)全(quan)充(chong)(chong)(chong)滿(man)開路(lu)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)高很多時，Buck或者降(jiang)(jiang)壓(ya)(ya)(ya)(ya)方(fang)案就是一個(ge)更好的(de)選擇。比如，在基于硬盤(pan)的(de)PMP中，通常使用單芯(xin)鋰離子電(dian)(dian)(dian)(dian)(dian)池，全(quan)充(chong)(chong)(chong)滿(man)開路(lu)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)是4.2V，容量從1200到2400mAh不等。而現在PMP通常是用汽車套件來充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)，它的(de)輸(shu)(shu)(shu)出電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)在9V到16V之間。在輸(shu)(shu)(shu)入電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)和電(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)之間比較高的(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)差(最(zui)小4.8V)會讓線性方(fang)案降(jiang)(jiang)低(di)(di)效率(lv)。這(zhe)種低(di)(di)效率(lv)，加上大于1.2A的(de)1C快速充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流，會產生嚴重的(de)散熱問(wen)題。為避(bi)免這(zhe)種情況，就要采用Buck方(fang)案。圖3為鋰電(dian)(dian)(dian)(dian)(dian)池充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)器方(fang)案示意(yi)圖,基本結(jie)構同Buck(降(jiang)(jiang)壓(ya)(ya)(ya)(ya))開關電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)調節器完全(quan)相(xiang)同。

2.3 SEPIC(升(sheng)壓與降壓)開(kai)關(guan)方案

在(zai)(zai)某(mou)些使用(yong)3個(ge)甚至4個(ge)鋰(li)離子(zi)／聚合物電(dian)(dian)(dian)(dian)芯(xin)串聯的(de)設備中，充電(dian)(dian)(dian)(dian)器(qi)(qi)的(de)輸(shu)(shu)入電(dian)(dian)(dian)(dian)壓(ya)(ya)就不總是大于(yu)電(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)壓(ya)(ya)。比(bi)如，筆記本電(dian)(dian)(dian)(dian)腦使用(yong)3芯(xin)鋰(li)離子(zi)電(dian)(dian)(dian)(dian)池(chi)組(zu)(zu)，滿充開(kai)路電(dian)(dian)(dian)(dian)壓(ya)(ya)是12．6V(4．2V x3)，容量(liang)從1800mAh到(dao)3600mAh。輸(shu)(shu)入電(dian)(dian)(dian)(dian)源要(yao)么是輸(shu)(shu)出(chu)電(dian)(dian)(dian)(dian)壓(ya)(ya)1 6V的(de)AC／DC適配器(qi)(qi)，要(yao)么是汽(qi)車套件，輸(shu)(shu)出(chu)電(dian)(dian)(dian)(dian)壓(ya)(ya)在(zai)(zai)9V到(dao)16V之間。很顯然地，線性和(he)Buck方案(an)都不能為這組(zu)(zu)電(dian)(dian)(dian)(dian)池(chi)組(zu)(zu)充電(dian)(dian)(dian)(dian)。這就要(yao)用(yong)上SEPIC方案(an)，它能在(zai)(zai)輸(shu)(shu)出(chu)電(dian)(dian)(dian)(dian)壓(ya)(ya)高于(yu)電(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)壓(ya)(ya)時(shi)工(gong)作(zuo)，也能在(zai)(zai)輸(shu)(shu)出(chu)電(dian)(dian)(dian)(dian)壓(ya)(ya)低于(yu)電(dian)(dian)(dian)(dian)池(chi)時(shi)工(gong)作(zuo)。

3、電量檢測算法

許多可(ke)(ke)攜式(shi)產品都利用電(dian)壓測(ce)(ce)量(liang)值來估(gu)計(ji)電(dian)池(chi)(chi)剩馀(yu)電(dian)量(liang)，但是電(dian)池(chi)(chi)電(dian)壓與剩馀(yu)電(dian)量(liang)的(de)關系(xi)卻會隨著放(fang)電(dian)率、溫度(du)和電(dian)池(chi)(chi)老化程度(du)而改變，使(shi)這種方法的(de)誤差率最高可(ke)(ke)達50％。市場對使(shi)用時間(jian)更長的(de)產品需(xu)求不斷增強，因此系(xi)統設計(ji)人員需(xu)要更加(jia)精(jing)確的(de)解決方案(an)。使(shi)用電(dian)量(liang)檢(jian)測(ce)(ce)計(ji)吧來測(ce)(ce)量(liang)電(dian)池(chi)(chi)充人或消耗(hao)的(de)電(dian)量(liang)，將能(neng)夠(gou)在很寬的(de)應用電(dian)源(yuan)級別范圍內提(ti)供(gong)更精(jing)確的(de)電(dian)池(chi)(chi)電(dian)量(liang)估(gu)測(ce)(ce)。

3.1電(dian)量檢測算法應用舉例之一,功能完整(zheng)的單＼雙(shuang)電(dian)池便攜式應用電(dian)池組設計

*電(dian)(dian)(dian)(dian)(dian)量(liang)(liang)(liang)檢(jian)測(ce)(ce)(ce)原(yuan)理(li).較好(hao)的(de)(de)電(dian)(dian)(dian)(dian)(dian)量(liang)(liang)(liang)檢(jian)測(ce)(ce)(ce)計(ji)至少要(yao)具(ju)備電(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)壓(ya)、電(dian)(dian)(dian)(dian)(dian)池(chi)組溫度和(he)電(dian)(dian)(dian)(dian)(dian)流(liu)、測(ce)(ce)(ce)量(liang)(liang)(liang)方法(fa)；一個微處理(li)9a；和(he)一套及業經驗證(zheng)的(de)(de)電(dian)(dian)(dian)(dian)(dian)量(liang)(liang)(liang)檢(jian)測(ce)(ce)(ce)算(suan)法(fa)。bq2650x及bq27x00是(shi)功能完整的(de)(de)電(dian)(dian)(dian)(dian)(dian)量(liang)(liang)(liang)檢(jian)測(ce)(ce)(ce)計(ji)，具(ju)有一個測(ce)(ce)(ce)量(liang)(liang)(liang)電(dian)(dian)(dian)(dian)(dian)壓(ya)與溫度的(de)(de)模數轉換器(qi)(qi)(ADC)和(he)一個測(ce)(ce)(ce)量(liang)(liang)(liang)電(dian)(dian)(dian)(dian)(dian)流(liu)與充(chong)電(dian)(dian)(dian)(dian)(dian)感測(ce)(ce)(ce)的(de)(de)模數轉換器(qi)(qi)。這些(xie)電(dian)(dian)(dian)(dian)(dian)量(liang)(liang)(liang)檢(jian)測(ce)(ce)(ce)計(ji)還具(ju)有一個微處理(li)器(qi)(qi)，負(fu)(fu)責執行(xing)德州儀(yi)器(qi)(qi)的(de)(de)電(dian)(dian)(dian)(dian)(dian)量(liang)(liang)(liang)檢(jian)測(ce)(ce)(ce)算(suan)法(fa)。這些(xie)演算(suan)法(fa)會補(bu)償(chang)鋰離子電(dian)(dian)(dian)(dian)(dian)池(chi)的(de)(de)自放電(dian)(dian)(dian)(dian)(dian)、老化、溫度和(he)放電(dian)(dian)(dian)(dian)(dian)率等因素。晶片(pian)內含微處理(li)器(qi)(qi)為主機(ji)系(xi)統(tong)(tong)處理(li)器(qi)(qi)省下這些(xie)計(ji)算(suan)負(fu)(fu)擔.電(dian)(dian)(dian)(dian)(dian)量(liang)(liang)(liang)檢(jian)測(ce)(ce)(ce)計(ji)能夠提供(gong)剩余電(dian)(dian)(dian)(dian)(dian)量(liang)(liang)(liang)狀態等信息，bq27x00系(xi)列產品還提供(gong)剩余可(ke)運(yun)行(xing)時間(jian)(Run Time to Empty)主機(ji)可(ke)隨(sui)時向電(dian)(dian)(dian)(dian)(dian)量(liang)(liang)(liang)檢(jian)測(ce)(ce)(ce)計(ji)查詢這些(xie)信息，再透(tou)過LED指示燈或(huo)屏幕顯示將電(dian)(dian)(dian)(dian)(dian)池(chi)信息通知用戶。電(dian)(dian)(dian)(dian)(dian)量(liang)(liang)(liang)檢(jian)測(ce)(ce)(ce)計(ji)的(de)(de)使用非常(chang)方便，系(xi)統(tong)(tong)處理(li)器(qi)(qi)僅需要(yao)配置12C或(huo)HDQ通信驅動器(qi)(qi)即可(ke)。

*電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)組(zu)(zu)電(dian)(dian)(dian)(dian)路(lu)描述.圖4(a)為可(ke)(ke)選(xuan)用具有鑒(jian)定功能IC的(de)(de)(de)(de)典型的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)組(zu)(zu)應(ying)用電(dian)(dian)(dian)(dian)路(lu)。根據所使用電(dian)(dian)(dian)(dian)量(liang)檢測(ce)(ce)(ce)(ce)計IC的(de)(de)(de)(de)不同，電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)組(zu)(zu)至少需要有三(san)到(dao)(dao)四(si)個(ge)外部終端。VCC及(ji)BAT引腳會連到(dao)(dao)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)電(dian)(dian)(dian)(dian)壓(ya)，以便為，C供(gong)電(dian)(dian)(dian)(dian)及(ji)測(ce)(ce)(ce)(ce)量(liang)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)電(dian)(dian)(dian)(dian)壓(ya)。電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)接地端連接了一個(ge)電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)值較小的(de)(de)(de)(de)檢測(ce)(ce)(ce)(ce)電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)器，讓(rang)電(dian)(dian)(dian)(dian)量(liang)檢測(ce)(ce)(ce)(ce)計的(de)(de)(de)(de)高(gao)阻(zu)(zu)(zu)抗SRP及(ji)SRN輸入端能夠(gou)監(jian)控感測(ce)(ce)(ce)(ce)電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)兩端的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)壓(ya)。通過流經檢測(ce)(ce)(ce)(ce)電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)器的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)流可(ke)(ke)用來判斷電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)充入或釋放的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)量(liang)。設計人員選(xuan)擇檢測(ce)(ce)(ce)(ce)電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)值時(shi)(shi)必須考慮電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)兩端的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)壓(ya)不能超過100 mV，過低的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)值可(ke)(ke)能會在電(dian)(dian)(dian)(dian)流較小時(shi)(shi)產(chan)生誤差。電(dian)(dian)(dian)(dian)路(lu)板布局(ju)必須確保從SRP及(ji)SRN到(dao)(dao)檢測(ce)(ce)(ce)(ce)電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)器的(de)(de)(de)(de)連接要盡可(ke)(ke)能靠近感測(ce)(ce)(ce)(ce)電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)端；換言之，它們應(ying)該是(shi)采用Kelvin連線(xian)。

HDQ引腳需要外部上(shang)拉電(dian)(dian)阻器，該電(dian)(dian)阻應(ying)位于主機或(huo)主應(ying)用端，這樣電(dian)(dian)量(liang)檢測(ce)計(ji)才(cai)能(neng)在電(dian)(dian)池組與便攜(xie)式設備連接斷開時啟用睡眠功能(neng)。建議上(shang)拉電(dian)(dian)阻值選用10 kΩ。

*電(dian)(dian)(dian)池(chi)(chi)組鑒(jian)定。價格低(di)廉(lian)的(de)偽冒電(dian)(dian)(dian)池(chi)(chi)的(de)問題日益嚴重(zhong)(zhong)，這(zhe)些電(dian)(dian)(dian)池(chi)(chi)可能(neng)不包(bao)含(han)OEM廠商要求的(de)安全保(bao)護(hu)電(dian)(dian)(dian)路(lu)。所以(yi)，真品(pin)電(dian)(dian)(dian)池(chi)(chi)組可包(bao)含(han)圖4(a)所示的(de)鑒(jian)定電(dian)(dian)(dian)路(lu)。當要鑒(jian)定電(dian)(dian)(dian)池(chi)(chi)時，主(zhu)機向含(han)有IC(bq26150，作用是(shi)循(xun)環冗余校(xiao)驗(CRC))的(de)電(dian)(dian)(dian)池(chi)(chi)組發出一(yi)個(ge)詢(xun)問值(challenge)，電(dian)(dian)(dian)池(chi)(chi)組所含(han)的(de)CRC會根據這(zhe)個(ge)詢(xun)問值和，IC中(zhong)(zhong)內(nei)建的(de)CRC多項式計(ji)(ji)算這(zhe)個(ge)CRC值。CRC是(shi)基于主(zhu)機的(de)查詢(xun)命(ming)令與IC中(zhong)(zhong)秘密定義的(de)CRC多項式完成(cheng)的(de)，主(zhu)機也會進行CRC值計(ji)(ji)算井與電(dian)(dian)(dian)池(chi)(chi)組的(de)計(ji)(ji)算結(jie)果比較以(yi)確定鑒(jian)定是(shi)否成(cheng)功。一(yi)旦電(dian)(dian)(dian)池(chi)(chi)通過(guo)鑒(jian)定，bq26150則會發出指令以(yi)確保(bao)主(zhu)機與電(dian)(dian)(dian)量檢測計(ji)(ji)之間的(de)資料線路(lu)通訊正常。當電(dian)(dian)(dian)池(chi)(chi)連(lian)接中(zhong)(zhong)斷或(huo)重(zhong)(zhong)新(xin)連(lian)接時，整(zheng)個(ge)鑒(jian)定過(guo)程將重(zhong)(zhong)復一(yi)次(ci)。

3.2電(dian)量檢測算法應用舉(ju)例之二,能(neng)適(shi)用于(yu)各(ge)種通用電(dian)量計的新型IC.

當今(jin)不少制(zhi)造廠(chang)商(shang)可提供種(zhong)類豐(feng)富的(de)電量(liang)計IC,，用(yong)戶(hu)可從中(zhong)選取合適的(de)功能器件，以優化(hua)產品的(de)性價比(bi)。利用(yong)電量(liang)計貯測(ce)量(liang)的(de)電池(chi)參數(shu)，這種(zhong)分(fen)離(li)式架構(gou)允(yun)許用(yong)戶(hu)在主(zhu)機內定(ding)制(zhi)電量(liang)計量(liang)算(suan)法．從而省(sheng)去電池(chi)組內嵌處理器的(de)成本。值此以Dallase semicconductor公司名(ming)為例的(de)DS2762芯片作典型(xing)(xing)分(fen)析. 一(yi)新型(xing)(xing)分(fen)離(li)式電量(liang)計IC,其結構(gou)見圖5(a)所示.

*DS2762應用特征

DS2762是(shi)一(yi)(yi)款單節鋰電(dian)(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)(dian)量計與保(bao)(bao)護(hu)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)，集(ji)(ji)成(cheng)(cheng)于(yu)一(yi)(yi)片(pian)微小(xiao)(xiao)的2.46mm× 2.74mm倒裝片(pian)封裝。由于(yu)內部集(ji)(ji)成(cheng)(cheng)了用于(yu)電(dian)(dian)(dian)(dian)(dian)(dian)量檢(jian)測的高(gao)(gao)精密電(dian)(dian)(dian)(dian)(dian)(dian)阻，該款器(qi)件非常節省空間。它(ta)所具有的小(xiao)(xiao)尺寸和(he)無(wu)可比擬的高(gao)(gao)集(ji)(ji)成(cheng)(cheng)度，對于(yu)移動電(dian)(dian)(dian)(dian)(dian)(dian)話電(dian)(dian)(dian)(dian)(dian)(dian)池組及其它(ta)類(lei)似的手(shou)持(chi)產(chan)品，如PDA等，都非常理(li)想。集(ji)(ji)成(cheng)(cheng)的保(bao)(bao)護(hu)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)連(lian)續地監(jian)(jian)視(shi)電(dian)(dian)(dian)(dian)(dian)(dian)池的過(guo)壓、欠壓和(he)過(guo)流(liu)故障(充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)或(huo)放電(dian)(dian)(dian)(dian)(dian)(dian)期間)。不(bu)同于(yu)獨立的保(bao)(bao)護(hu)IC，DS2762允(yun)許主處理(li)器(qi)監(jian)(jian)視(shi)/控制保(bao)(bao)護(hu)FET的導通(tong)(tong)狀態，這樣，可以通(tong)(tong)過(guo)DS2762的保(bao)(bao)護(hu)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)實現系統電(dian)(dian)(dian)(dian)(dian)(dian)源控制。DS2762也(ye)可以充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)一(yi)(yi)個已(yi)深(shen)度消耗(hao)的電(dian)(dian)(dian)(dian)(dian)(dian)池，當電(dian)(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)(dian)壓不(bu)足3V時(shi)，提供一(yi)(yi)條限制電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)的恢復充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)徑。

DS2762能(neng)夠精確監視電(dian)(dian)池(chi)電(dian)(dian)流、電(dian)(dian)壓和溫度(du)(du)，其動態(tai)范圍與分(fen)(fen)辨率滿足(zu)任何通(tong)行的(de)(de)(de)移動通(tong)信產品的(de)(de)(de)測(ce)試標準。測(ce)得的(de)(de)(de)電(dian)(dian)流對內(nei)部產生的(de)(de)(de)時基(ji)進(jin)(jin)行積分(fen)(fen)，實現(xian)電(dian)(dian)量(liang)計(ji)量(liang)。通(tong)過(guo)實時、連(lian)續的(de)(de)(de)自動失調糾(jiu)正，電(dian)(dian)量(liang)計(ji)量(liang)的(de)(de)(de)精度(du)(du)得以提(ti)高(gao)。內(nei)置的(de)(de)(de)檢測(ce)電(dian)(dian)阻(zu)消除了(le)因制造工藝和溫度(du)(du)而造成的(de)(de)(de)電(dian)(dian)阻(zu)變化，進(jin)(jin)一(yi)步提(ti)高(gao)了(le)電(dian)(dian)量(liang)計(ji)的(de)(de)(de)精度(du)(du)。重要數據保存(cun)于(yu)32字節(jie)、可(ke)加鎖(suo)的(de)(de)(de)EEPROM；16字節(jie)的(de)(de)(de)SRAM用于(yu)保存(cun)動態(tai)數據。與DS2762的(de)(de)(de)所(suo)有(you)通(tong)信均通(tong)過(guo)1-Wire、多節(jie)點通(tong)信接口進(jin)(jin)行，最大限度(du)(du)減少了(le)電(dian)(dian)池(chi)組與主機的(de)(de)(de)連(lian)線。其主要特征為；單節(jie)鋰電(dian)(dian)池(chi)保護(hu)器；高(gao)精度(du)(du)電(dian)(dian)流(電(dian)(dian)量(liang)計(ji)量(liang))、電(dian)(dian)壓和溫度(du)(du)測(ce)量(liang)；可(ke)選的(de)(de)(de)集成25mΩ檢測(ce)電(dian)(dian)阻(zu)，每個DS2762經過(guo)單獨微(wei)調；0V電(dian)(dian)池(chi)恢復充電(dian)(dian)；32字節(jie)可(ke)加鎖(suo)EEPROM，16字節(jie)SRAM，64位ROM；

1-Wire，多(duo)節點，數字通(tong)信接(jie)口；支持多(duo)電池組電源(yuan)管理，并通(tong)過保護FET實現系統電源(yuan)控制；休眠(mian)模(mo)式下(xia)(xia)電源(yuan)電流(liu)僅2?A(最(zui)大(da)(da));工作模(mo)式下(xia)(xia)電源(yuan)電流(liu)為90?A(最(zui)大(da)(da));2.46mm×2.74mm倒裝片封(feng)裝或16引腳下(xia)(xia)SSOP封(feng)裝，兩者均可選擇(ze)帶(dai)或不帶(dai)檢測電阻(zu);復(fu)具有(you)備(bei)有(you)評估板.

4、結論

應(ying)用好便攜式電(dian)(dian)子(zi)(zi)設備的電(dian)(dian)池技術是選(xuan)擇鋰(li)(li)離子(zi)(zi)電(dian)(dian)池和鋰(li)(li)聚合物電(dian)(dian)池及其充電(dian)(dian)器的基礎.之于如(ru)何正確(que)選(xuan)擇,還(huan)必須視便攜式電(dian)(dian)子(zi)(zi)備的具體要求(qiu)而定(ding)。