如(ru)今(jin)的(de)(de)便(bian)攜(xie)(xie)式電(dian)(dian)(dian)子(zi)備(bei)(bei)中電(dian)(dian)(dian)池技術(shu)包括(kuo)電(dian)(dian)(dian)量檢(jian)測算法(fa)、電(dian)(dian)(dian)池充(chong)電(dian)(dian)(dian)算法(fa)與(yu)(yu)電(dian)(dian)(dian)池充(chong)電(dian)(dian)(dian)技術(shu)等(deng)幾個方面。眾所周知,充(chong)電(dian)(dian)(dian)式電(dian)(dian)(dian)池化學(xue)反(fan)應有鎳鎘(ge)、鎳氫、鋰(li)離子(zi)和鋰(li)聚合物4種(zhong)程(cheng)(cheng)式,作為便(bian)攜(xie)(xie)式電(dian)(dian)(dian)子(zi)設(she)備(bei)(bei)來說,雖然(ran)這4種(zhong)電(dian)(dian)(dian)池程(cheng)(cheng)式各有特點,但從能量密度與(yu)(yu)安全性角度的(de)(de)發展與(yu)(yu)實(shi)踐可知, 鋰(li)離子(zi)電(dian)(dian)(dian)池和鋰(li)聚合物電(dian)(dian)(dian)池的(de)(de)優(you)勢己成(cheng)為小型長運行時間的(de)(de)設(she)備(bei)(bei)的(de)(de)理(li)想之(zhi)選(xuan)(xuan)，比如(ru)筆記本電(dian)(dian)(dian)腦(nao)以(yi)及基于硬盤的(de)(de)PMP等(deng).對便(bian)攜(xie)(xie)式電(dian)(dian)(dian)子(zi)備(bei)(bei)工程(cheng)(cheng)師來說，正確選(xuan)(xuan)擇與(yu)(yu)應用(yong)好(hao)便(bian)攜(xie)(xie)式電(dian)(dian)(dian)子(zi)備(bei)(bei)中電(dian)(dian)(dian)池技術(shu)至(zhi)關重(zhong)要,值此(ci)本文將對此(ci)作研討(tao),并作應用(yong)舉例分析.

1、關于(yu)細流充(chong)電(dian)(dian)、快速充(chong)電(dian)(dian)和穩定充(chong)電(dian)(dian)的電(dian)(dian)池充(chong)電(dian)(dian)算法

根(gen)據最終(zhong)應用(yong)的(de)(de)(de)能量需求，一個電(dian)(dian)池(chi)(chi)組可(ke)能包含最多(duo)4個鋰(li)離子或鋰(li)聚合物電(dian)(dian)池(chi)(chi)芯,其(qi)配(pei)(pei)置(zhi)可(ke)有多(duo)種變化，同(tong)時帶(dai)有一個主流的(de)(de)(de)電(dian)(dian)源(yuan)適(shi)(shi)配(pei)(pei)器(qi)：直接(jie)的(de)(de)(de)適(shi)(shi)配(pei)(pei)器(qi)、USB接(jie)口或汽車充電(dian)(dian)器(qi)。除去電(dian)(dian)芯數量、電(dian)(dian)芯的(de)(de)(de)配(pei)(pei)置(zhi)或電(dian)(dian)源(yuan)適(shi)(shi)配(pei)(pei)器(qi)類型上(shang)的(de)(de)(de)差別，這些電(dian)(dian)池(chi)(chi)組都有同(tong)樣的(de)(de)(de)充電(dian)(dian)特(te)性。因此(ci)它們的(de)(de)(de)充電(dian)(dian)算法也一樣。鋰(li)離子與鋰(li)聚合物電(dian)(dian)池(chi)(chi)最好的(de)(de)(de)充電(dian)(dian)算法可(ke)以(yi)分為3個階段：細流充電(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(wen)定(ding)(ding)電(dian)(dian)壓。在快速(su)充(chong)電(dian)(dian)過程(cheng)中(zhong)，一旦電(dian)(dian)芯電(dian)(dian)壓達(da)到4.2V，穩(wen)定(ding)(ding)電(dian)(dian)壓階段就開始了。這(zhe)時可通過最(zui)(zui)小(xiao)充(chong)電(dian)(dian)電(dian)(dian)流或定(ding)(ding)時器或這(zhe)兩者的聯合來中(zhong)斷充(chong)電(dian)(dian).當最(zui)(zui)小(xiao)電(dian)(dian)流低于大約0.07C時，可中(zhong)斷充(chong)電(dian)(dian)。定(ding)(ding)時器則(ze)要靠一個預設的定(ding)(ding)時器來觸發中(zhong)斷。

高級的電池充電器通常帶有附加的安(an)全功能。比如，如果(guo)電(dian)(dian)(dian)芯溫度超出給(gei)定窗口(kou)，通常是0℃--45℃，充(chong)電(dian)(dian)(dian)就會暫停。除去某些非常低端的設備，現在市(shi)面上的鋰(li)離子(zi)／鋰(li)聚合(he)物電(dian)(dian)(dian)池充(chong)電(dian)(dian)(dian)方案都集成或(huo)是帶有外(wai)置(zhi)的元件，以便按照充(chong)電(dian)(dian)(dian)特(te)性進(jin)行充(chong)電(dian)(dian)(dian)，這不(bu)光是為(wei)了取得更佳充(chong)電(dian)(dian)(dian)效果(guo)，同時(shi)也是為(wei)了安(an)全。

2、鋰離(li)子/聚合物電池(chi)充電方案

鋰離子/聚(ju)合物電池的(de)(de)充(chong)電方案對于不(bu)同數量的(de)(de)電芯、電芯配置以及(ji)電源(yuan)類型還是不(bu)同的(de)(de)。目(mu)前主要有(you)3種主要的(de)(de)充(chong)電方案：線性，Buck(降壓(ya))開(kai)關和(he)SEPIC(升壓(ya)與降壓(ya))開(kai)關。

2.1線性方案

當(dang)充(chong)(chong)電(dian)器(qi)輸(shu)入電(dian)壓(ya)(ya)大于(yu)全充(chong)(chong)滿(man)電(dian)芯(xin)加上充(chong)(chong)足凈空之后的開路(lu)電(dian)壓(ya)(ya)時(shi)，最好(hao)用線(xian)性(xing)方案，特別是(shi)(shi)1.0C快速(su)充(chong)(chong)電(dian)電(dian)流不(bu)比(bi)1A大太多(duo)時(shi)。比(bi)如，MP3播放(fang)(fang)器(qi)通常(chang)只有(you)一個(ge)電(dian)芯(xin)，容(rong)量從700到1500mAh不(bu)等，滿(man)充(chong)(chong)開路(lu)電(dian)壓(ya)(ya)是(shi)(shi)4.2V。MP3播放(fang)(fang)機的電(dian)源通常(chang)是(shi)(shi)AC／DC適配器(qi)或者是(shi)(shi)USB接口(kou)，其輸(shu)出(chu)是(shi)(shi)規則的5V；這時(shi)，線(xian)性(xing)方案的充(chong)(chong)電(dian)器(qi)就是(shi)(shi)最簡單、最有(you)效(xiao)率的方案。圖2所示為鋰離(li)子/聚合物電(dian)池充(chong)(chong)電(dian)方案線(xian)性(xing)方案,基本結構和線(xian)性(xing)電(dian)壓(ya)(ya)規整器(qi)一樣。

*線性(xing)(xing)方案的(de)充(chong)電(dian)(dian)器(qi)(qi)應用(yong)例(li)舉(ju)-雙輸(shu)入Li+充(chong)電(dian)(dian)器(qi)(qi)及(ji)智能電(dian)(dian)源選擇器(qi)(qi)MAX8677A。MAX8677A是(shi)雙輸(shu)入USB/AC適配(pei)器(qi)(qi)線性(xing)(xing)充(chong)電(dian)(dian)器(qi)(qi)，內置Smart Power Selector，用(yong)于由可充(chong)電(dian)(dian)單節Li+電(dian)(dian)池供電(dian)(dian)的(de)便攜(xie)式設(she)備(bei)(bei)。該(gai)充(chong)電(dian)(dian)器(qi)(qi)集(ji)成(cheng)了電(dian)(dian)池和(he)外部(bu)電(dian)(dian)源充(chong)電(dian)(dian)和(he)切(qie)換負(fu)載所需的(de)全部(bu)功率開(kai)關，因此無需外部(bu) MOSFET。MAX8677A理(li)想(xiang)用(yong)于便攜(xie)式設(she)備(bei)(bei)，例(li)如智能手(shou)機、PDA、便攜(xie)式多媒體(ti)播放器(qi)(qi)、GPS導航設(she)備(bei)(bei)、數碼相機、以及(ji)數碼攝像機。

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)源(yuan)選擇器自動將電(dian)(dian)池(chi)切換到系統負(fu)載，使用系統未利(li)用的(de)(de)輸(shu)入(ru)(ru)電(dian)(dian)源(yuan)部分為(wei)電(dian)(dian)池(chi)充(chong)電(dian)(dian)，充(chong)分利(li)用有(you)限的(de)(de)USB和適配器輸(shu)入(ru)(ru)電(dian)(dian)源(yuan)。所有(you)需要(yao)的(de)(de)電(dian)(dian)流檢測(ce)電(dian)(dian)路，包括(kuo)集(ji)成的(de)(de)功率開(kai)關，均(jun)集(ji)成于(yu)片上。DC輸(shu)入(ru)(ru)電(dian)(dian)流限最高(gao)可(ke)調節(jie)至(zhi)2A，而(er)DC和USB輸(shu)入(ru)(ru)均(jun)可(ke)支(zhi)持100mA、500mA、和USB掛起模式。充(chong)電(dian)(dian)電(dian)(dian)流可(ke)調節(jie)至(zhi)高(gao)達1.5A，從而(er)支(zhi)持 寬(kuan)范圍(wei)(wei)的(de)(de)電(dian)(dian)池(chi)容性。MAX8677A的(de)(de)其(qi)他(ta)特性包括(kuo)熱調節(jie)、過壓(ya)保護、充(chong)電(dian)(dian)狀態(tai)和故障輸(shu)出、電(dian)(dian)源(yuan)好(hao)監視(shi)、電(dian)(dian)池(chi)熱敏電(dian)(dian)阻(zu)監視(shi)、以及充(chong)電(dian)(dian)定時器。MAX8677A采用節(jie)省(sheng)空間的(de)(de)、熱增強(qiang)型、4mm×4mm、24引腳的(de)(de)TQFN封裝，規定工作于(yu)擴展(zhan)級溫度(du)范圍(wei)(wei)(-40～+85℃)。

2.2 Buck(降壓(ya))開關方案(an)

當1.0C充(chong)(chong)電(dian)(dian)(dian)的(de)電(dian)(dian)(dian)流(liu)大于1A，或者輸(shu)入電(dian)(dian)(dian)壓(ya)(ya)比(bi)電(dian)(dian)(dian)芯(xin)的(de)全充(chong)(chong)滿開路電(dian)(dian)(dian)壓(ya)(ya)高很多時(shi)，Buck或者降壓(ya)(ya)方案(an)就是(shi)(shi)一個更好的(de)選擇。比(bi)如，在基(ji)于硬盤的(de)PMP中，通(tong)常使用單芯(xin)鋰(li)離(li)子電(dian)(dian)(dian)池，全充(chong)(chong)滿開路電(dian)(dian)(dian)壓(ya)(ya)是(shi)(shi)4.2V，容量從1200到(dao)2400mAh不(bu)等(deng)。而(er)現在PMP通(tong)常是(shi)(shi)用汽車套件來充(chong)(chong)電(dian)(dian)(dian)，它的(de)輸(shu)出電(dian)(dian)(dian)壓(ya)(ya)在9V到(dao)16V之間(jian)。在輸(shu)入電(dian)(dian)(dian)壓(ya)(ya)和電(dian)(dian)(dian)池電(dian)(dian)(dian)壓(ya)(ya)之間(jian)比(bi)較(jiao)高的(de)電(dian)(dian)(dian)壓(ya)(ya)差(cha)(最小4.8V)會讓(rang)線性方案(an)降低效率。這種低效率，加上大于1.2A的(de)1C快速充(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)，會產生嚴重的(de)散(san)熱問題。為避免這種情況(kuang)，就要采用Buck方案(an)。圖(tu)3為鋰(li)電(dian)(dian)(dian)池充(chong)(chong)電(dian)(dian)(dian)器(qi)方案(an)示意圖(tu),基(ji)本結構(gou)同(tong)Buck(降壓(ya)(ya))開關(guan)電(dian)(dian)(dian)壓(ya)(ya)調(diao)節器(qi)完全相同(tong)。

2.3 SEPIC(升壓與降壓)開關方案(an)

在(zai)某些(xie)使用(yong)3個甚至4個鋰離(li)子／聚合物電(dian)(dian)(dian)(dian)芯串聯的設(she)備(bei)中，充電(dian)(dian)(dian)(dian)器的輸(shu)(shu)(shu)入電(dian)(dian)(dian)(dian)壓就(jiu)不總(zong)是(shi)(shi)大于(yu)電(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)壓。比如，筆記本電(dian)(dian)(dian)(dian)腦使用(yong)3芯鋰離(li)子電(dian)(dian)(dian)(dian)池(chi)組，滿充開路電(dian)(dian)(dian)(dian)壓是(shi)(shi)12．6V(4．2V x3)，容(rong)量從1800mAh到3600mAh。輸(shu)(shu)(shu)入電(dian)(dian)(dian)(dian)源要(yao)么(me)是(shi)(shi)輸(shu)(shu)(shu)出(chu)電(dian)(dian)(dian)(dian)壓1 6V的AC／DC適(shi)配器，要(yao)么(me)是(shi)(shi)汽(qi)車(che)套(tao)件，輸(shu)(shu)(shu)出(chu)電(dian)(dian)(dian)(dian)壓在(zai)9V到16V之間。很顯(xian)然地(di)，線性和Buck方案都不能(neng)為這(zhe)組電(dian)(dian)(dian)(dian)池(chi)組充電(dian)(dian)(dian)(dian)。這(zhe)就(jiu)要(yao)用(yong)上SEPIC方案，它能(neng)在(zai)輸(shu)(shu)(shu)出(chu)電(dian)(dian)(dian)(dian)壓高于(yu)電(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)壓時工作，也能(neng)在(zai)輸(shu)(shu)(shu)出(chu)電(dian)(dian)(dian)(dian)壓低于(yu)電(dian)(dian)(dian)(dian)池(chi)時工作。

3、電量檢測算法

許多可攜式(shi)產(chan)品(pin)都利(li)用(yong)電(dian)(dian)壓(ya)測(ce)量(liang)值來(lai)估計電(dian)(dian)池(chi)(chi)剩(sheng)馀電(dian)(dian)量(liang)，但是電(dian)(dian)池(chi)(chi)電(dian)(dian)壓(ya)與(yu)剩(sheng)馀電(dian)(dian)量(liang)的(de)(de)(de)(de)關(guan)系卻會隨著(zhu)放電(dian)(dian)率(lv)、溫度(du)(du)和電(dian)(dian)池(chi)(chi)老化(hua)程度(du)(du)而(er)改變，使這種(zhong)方法的(de)(de)(de)(de)誤(wu)差(cha)率(lv)最高可達(da)50％。市場對使用(yong)時間更長的(de)(de)(de)(de)產(chan)品(pin)需(xu)求不斷(duan)增強，因此系統設計人員(yuan)需(xu)要更加精確的(de)(de)(de)(de)解決方案。使用(yong)電(dian)(dian)量(liang)檢測(ce)計吧來(lai)測(ce)量(liang)電(dian)(dian)池(chi)(chi)充人或消(xiao)耗的(de)(de)(de)(de)電(dian)(dian)量(liang)，將能夠在很寬的(de)(de)(de)(de)應用(yong)電(dian)(dian)源級別范圍內提(ti)供更精確的(de)(de)(de)(de)電(dian)(dian)池(chi)(chi)電(dian)(dian)量(liang)估測(ce)。

3.1電(dian)量(liang)檢測算法應(ying)用(yong)舉例之一,功能完整的單(dan)＼雙電(dian)池便(bian)攜(xie)式(shi)應(ying)用(yong)電(dian)池組設(she)計

*電(dian)量(liang)檢(jian)測(ce)(ce)原(yuan)理(li)(li).較好的(de)電(dian)量(liang)檢(jian)測(ce)(ce)計(ji)(ji)(ji)至少要具備(bei)電(dian)池(chi)(chi)電(dian)壓(ya)、電(dian)池(chi)(chi)組溫度(du)和電(dian)流、測(ce)(ce)量(liang)方法；一(yi)個(ge)(ge)微(wei)處(chu)理(li)(li)9a；和一(yi)套及業經驗證(zheng)的(de)電(dian)量(liang)檢(jian)測(ce)(ce)算法。bq2650x及bq27x00是(shi)功能(neng)完(wan)整的(de)電(dian)量(liang)檢(jian)測(ce)(ce)計(ji)(ji)(ji)，具有一(yi)個(ge)(ge)測(ce)(ce)量(liang)電(dian)壓(ya)與溫度(du)的(de)模數轉(zhuan)換(huan)器(qi)(qi)(ADC)和一(yi)個(ge)(ge)測(ce)(ce)量(liang)電(dian)流與充電(dian)感測(ce)(ce)的(de)模數轉(zhuan)換(huan)器(qi)(qi)。這些電(dian)量(liang)檢(jian)測(ce)(ce)計(ji)(ji)(ji)還具有一(yi)個(ge)(ge)微(wei)處(chu)理(li)(li)器(qi)(qi)，負(fu)(fu)責執行德州儀(yi)器(qi)(qi)的(de)電(dian)量(liang)檢(jian)測(ce)(ce)算法。這些演(yan)算法會補償鋰離子電(dian)池(chi)(chi)的(de)自放電(dian)、老化、溫度(du)和放電(dian)率等(deng)因素。晶片(pian)內含(han)微(wei)處(chu)理(li)(li)器(qi)(qi)為主機(ji)系(xi)統處(chu)理(li)(li)器(qi)(qi)省下(xia)這些計(ji)(ji)(ji)算負(fu)(fu)擔.電(dian)量(liang)檢(jian)測(ce)(ce)計(ji)(ji)(ji)能(neng)夠提供剩(sheng)余電(dian)量(liang)狀(zhuang)態等(deng)信(xin)(xin)息，bq27x00系(xi)列產品還提供剩(sheng)余可(ke)運行時(shi)間(Run Time to Empty)主機(ji)可(ke)隨時(shi)向電(dian)量(liang)檢(jian)測(ce)(ce)計(ji)(ji)(ji)查詢(xun)這些信(xin)(xin)息，再透過LED指示燈或屏幕顯示將電(dian)池(chi)(chi)信(xin)(xin)息通知用戶(hu)。電(dian)量(liang)檢(jian)測(ce)(ce)計(ji)(ji)(ji)的(de)使(shi)用非常方便，系(xi)統處(chu)理(li)(li)器(qi)(qi)僅需要配置12C或HDQ通信(xin)(xin)驅動(dong)器(qi)(qi)即可(ke)。

*電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)組(zu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路描述.圖4(a)為可選(xuan)用(yong)具有(you)鑒定(ding)功能(neng)IC的(de)(de)(de)典型(xing)的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)組(zu)應(ying)用(yong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路。根(gen)據所(suo)使(shi)用(yong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)量檢測(ce)(ce)計IC的(de)(de)(de)不同，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)組(zu)至少需要有(you)三到(dao)四個外部終端(duan)。VCC及BAT引(yin)腳會連(lian)(lian)到(dao)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)，以(yi)便為，C供電(dian)(dian)(dian)(dian)(dian)(dian)(dian)及測(ce)(ce)量電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)接地端(duan)連(lian)(lian)接了(le)一(yi)個電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)值較小(xiao)的(de)(de)(de)檢測(ce)(ce)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)器，讓電(dian)(dian)(dian)(dian)(dian)(dian)(dian)量檢測(ce)(ce)計的(de)(de)(de)高阻(zu)(zu)(zu)抗(kang)SRP及SRN輸入端(duan)能(neng)夠監控感(gan)測(ce)(ce)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)兩端(duan)的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)。通(tong)過(guo)(guo)(guo)流(liu)(liu)經檢測(ce)(ce)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)器的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)可用(yong)來判斷電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)充入或釋放的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)量。設計人(ren)員選(xuan)擇(ze)檢測(ce)(ce)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)值時必須考慮電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)兩端(duan)的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)不能(neng)超過(guo)(guo)(guo)100 mV，過(guo)(guo)(guo)低的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)值可能(neng)會在電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)較小(xiao)時產生誤差。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路板(ban)布局必須確(que)保從SRP及SRN到(dao)檢測(ce)(ce)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)器的(de)(de)(de)連(lian)(lian)接要盡(jin)可能(neng)靠近感(gan)測(ce)(ce)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)端(duan)；換言(yan)之，它(ta)們應(ying)該是采用(yong)Kelvin連(lian)(lian)線。

HDQ引腳需(xu)要外部上(shang)(shang)拉(la)(la)電阻器，該電阻應位于主(zhu)機或主(zhu)應用(yong)端(duan)，這樣電量檢測(ce)計才能(neng)在電池組與便攜式(shi)設備連(lian)接斷開時啟(qi)用(yong)睡眠(mian)功能(neng)。建議上(shang)(shang)拉(la)(la)電阻值(zhi)選用(yong)10 kΩ。

*電(dian)(dian)(dian)池(chi)(chi)組(zu)鑒(jian)定(ding)(ding)(ding)。價格低(di)廉的(de)(de)偽冒電(dian)(dian)(dian)池(chi)(chi)的(de)(de)問題日益嚴重(zhong)，這(zhe)些電(dian)(dian)(dian)池(chi)(chi)可能(neng)不包(bao)含OEM廠商要求的(de)(de)安全保護電(dian)(dian)(dian)路。所以(yi)，真品電(dian)(dian)(dian)池(chi)(chi)組(zu)可包(bao)含圖4(a)所示的(de)(de)鑒(jian)定(ding)(ding)(ding)電(dian)(dian)(dian)路。當要鑒(jian)定(ding)(ding)(ding)電(dian)(dian)(dian)池(chi)(chi)時(shi)，主機向含有(you)IC(bq26150，作(zuo)用是循環冗(rong)余(yu)校驗(CRC))的(de)(de)電(dian)(dian)(dian)池(chi)(chi)組(zu)發(fa)出一個詢(xun)問值(challenge)，電(dian)(dian)(dian)池(chi)(chi)組(zu)所含的(de)(de)CRC會(hui)根(gen)據這(zhe)個詢(xun)問值和，IC中(zhong)內(nei)建的(de)(de)CRC多項式計(ji)算這(zhe)個CRC值。CRC是基于主機的(de)(de)查詢(xun)命令與(yu)(yu)(yu)IC中(zhong)秘密定(ding)(ding)(ding)義(yi)的(de)(de)CRC多項式完成(cheng)的(de)(de)，主機也會(hui)進行CRC值計(ji)算井與(yu)(yu)(yu)電(dian)(dian)(dian)池(chi)(chi)組(zu)的(de)(de)計(ji)算結(jie)果(guo)比(bi)較以(yi)確定(ding)(ding)(ding)鑒(jian)定(ding)(ding)(ding)是否成(cheng)功。一旦(dan)電(dian)(dian)(dian)池(chi)(chi)通過(guo)鑒(jian)定(ding)(ding)(ding)，bq26150則會(hui)發(fa)出指令以(yi)確保主機與(yu)(yu)(yu)電(dian)(dian)(dian)量檢(jian)測計(ji)之間(jian)的(de)(de)資料線(xian)路通訊(xun)正常。當電(dian)(dian)(dian)池(chi)(chi)連接中(zhong)斷或重(zhong)新(xin)連接時(shi)，整個鑒(jian)定(ding)(ding)(ding)過(guo)程(cheng)將(jiang)重(zhong)復一次。

3.2電量檢測算法應(ying)用(yong)舉例之二(er),能適(shi)用(yong)于各種通用(yong)電量計的新型IC.

當今不少制造廠商可提供種類豐富(fu)的(de)電(dian)(dian)量(liang)計IC,，用戶(hu)可從中選(xuan)取合(he)適的(de)功能器件，以優化產品的(de)性價比。利用電(dian)(dian)量(liang)計貯測(ce)量(liang)的(de)電(dian)(dian)池參數，這(zhe)種分(fen)離式架構(gou)(gou)允許(xu)用戶(hu)在(zai)主機內定制電(dian)(dian)量(liang)計量(liang)算(suan)法．從而(er)省去(qu)電(dian)(dian)池組內嵌處理器的(de)成本(ben)。值(zhi)此(ci)以Dallase semicconductor公(gong)司名為例(li)的(de)DS2762芯(xin)片作典型(xing)分(fen)析. 一(yi)新(xin)型(xing)分(fen)離式電(dian)(dian)量(liang)計IC,其結(jie)構(gou)(gou)見圖5(a)所(suo)示.

*DS2762應(ying)用特征

DS2762是一款單節(jie)鋰(li)電(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)量(liang)(liang)計與(yu)保(bao)(bao)護(hu)電(dian)(dian)(dian)(dian)路，集(ji)成于一片微小的(de)(de)2.46mm× 2.74mm倒裝(zhuang)片封裝(zhuang)。由于內部集(ji)成了用于電(dian)(dian)(dian)(dian)量(liang)(liang)檢測的(de)(de)高(gao)精密(mi)電(dian)(dian)(dian)(dian)阻，該款器件非常(chang)節(jie)省空間。它所具有的(de)(de)小尺寸(cun)和無可(ke)比(bi)擬的(de)(de)高(gao)集(ji)成度，對(dui)于移動電(dian)(dian)(dian)(dian)話電(dian)(dian)(dian)(dian)池(chi)組及(ji)其它類(lei)似(si)的(de)(de)手持(chi)產品，如(ru)PDA等，都非常(chang)理(li)想。集(ji)成的(de)(de)保(bao)(bao)護(hu)電(dian)(dian)(dian)(dian)路連續地監視(shi)電(dian)(dian)(dian)(dian)池(chi)的(de)(de)過(guo)壓、欠壓和過(guo)流故障(zhang)(充電(dian)(dian)(dian)(dian)或放電(dian)(dian)(dian)(dian)期間)。不同(tong)于獨立的(de)(de)保(bao)(bao)護(hu)IC，DS2762允許(xu)主處理(li)器監視(shi)/控制(zhi)保(bao)(bao)護(hu)FET的(de)(de)導通狀(zhuang)態，這樣，可(ke)以(yi)(yi)通過(guo)DS2762的(de)(de)保(bao)(bao)護(hu)電(dian)(dian)(dian)(dian)路實現系統電(dian)(dian)(dian)(dian)源控制(zhi)。DS2762也可(ke)以(yi)(yi)充電(dian)(dian)(dian)(dian)一個已深度消耗的(de)(de)電(dian)(dian)(dian)(dian)池(chi)，當電(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)壓不足(zu)3V時，提供一條限制(zhi)電(dian)(dian)(dian)(dian)流的(de)(de)恢復充電(dian)(dian)(dian)(dian)路徑。

DS2762能夠精(jing)確監視電池電流(liu)、電壓和溫(wen)度(du)(du)(du)，其(qi)(qi)動態范圍(wei)與分(fen)辨率(lv)滿足任何通(tong)(tong)(tong)行的移動通(tong)(tong)(tong)信(xin)產品的測試標(biao)準。測得(de)的電流(liu)對內部產生的時基進行積分(fen)，實現電量(liang)計(ji)量(liang)。通(tong)(tong)(tong)過(guo)實時、連續的自(zi)動失(shi)調糾正(zheng)，電量(liang)計(ji)量(liang)的精(jing)度(du)(du)(du)得(de)以提高(gao)。內置的檢測電阻消(xiao)除了(le)因(yin)制造工(gong)藝和溫(wen)度(du)(du)(du)而(er)造成(cheng)的電阻變(bian)化，進一(yi)步提高(gao)了(le)電量(liang)計(ji)的精(jing)度(du)(du)(du)。重要(yao)數(shu)據保存于(yu)32字節、可(ke)加鎖(suo)的EEPROM；16字節的SRAM用于(yu)保存動態數(shu)據。與DS2762的所(suo)有(you)通(tong)(tong)(tong)信(xin)均通(tong)(tong)(tong)過(guo)1-Wire、多節點通(tong)(tong)(tong)信(xin)接口(kou)進行，最(zui)大限度(du)(du)(du)減少了(le)電池組與主機的連線。其(qi)(qi)主要(yao)特(te)征為；單節鋰(li)電池保護器；高(gao)精(jing)度(du)(du)(du)電流(liu)(電量(liang)計(ji)量(liang))、電壓和溫(wen)度(du)(du)(du)測量(liang)；可(ke)選的集(ji)成(cheng)25mΩ檢測電阻，每個DS2762經過(guo)單獨微調；0V電池恢復充(chong)電；32字節可(ke)加鎖(suo)EEPROM，16字節SRAM，64位ROM；

1-Wire，多(duo)節點，數字通信接口；支持多(duo)電池(chi)組電源(yuan)(yuan)管理，并通過保護FET實現系統電源(yuan)(yuan)控制；休眠模(mo)式下(xia)電源(yuan)(yuan)電流僅2?A(最(zui)大(da));工作模(mo)式下(xia)電源(yuan)(yuan)電流為(wei)90?A(最(zui)大(da));2.46mm×2.74mm倒裝片封(feng)裝或(huo)16引腳(jiao)下(xia)SSOP封(feng)裝，兩(liang)者均(jun)可(ke)選擇帶(dai)或(huo)不帶(dai)檢測(ce)電阻;復(fu)具有備有評估板.

4、結論

應用好便攜(xie)(xie)式(shi)電(dian)子設備(bei)的(de)電(dian)池(chi)技術是選擇(ze)鋰離子電(dian)池(chi)和鋰聚合物電(dian)池(chi)及其充電(dian)器的(de)基(ji)礎.之于(yu)如何正確選擇(ze),還必須(xu)視(shi)便攜(xie)(xie)式(shi)電(dian)子備(bei)的(de)具(ju)體要求而定。