如(ru)今的(de)便攜式電(dian)子備(bei)(bei)中電(dian)池(chi)(chi)(chi)技術包括電(dian)量檢(jian)測算(suan)法(fa)、電(dian)池(chi)(chi)(chi)充(chong)電(dian)算(suan)法(fa)與電(dian)池(chi)(chi)(chi)充(chong)電(dian)技術等幾個方面。眾所周(zhou)知,充(chong)電(dian)式電(dian)池(chi)(chi)(chi)化學反應(ying)有(you)鎳(nie)(nie)鎘、鎳(nie)(nie)氫、鋰(li)離(li)子和(he)鋰(li)聚合物(wu)4種程式,作(zuo)為便攜式電(dian)子設(she)(she)備(bei)(bei)來說(shuo),雖然(ran)這4種電(dian)池(chi)(chi)(chi)程式各有(you)特(te)點,但從能量密度與安全性角(jiao)度的(de)發展與實踐可知, 鋰(li)離(li)子電(dian)池(chi)(chi)(chi)和(he)鋰(li)聚合物(wu)電(dian)池(chi)(chi)(chi)的(de)優(you)勢己成為小(xiao)型(xing)長運行時間的(de)設(she)(she)備(bei)(bei)的(de)理想之選(xuan)，比如(ru)筆記本(ben)電(dian)腦以及(ji)基于硬盤(pan)的(de)PMP等.對便攜式電(dian)子備(bei)(bei)工程師來說(shuo)，正確選(xuan)擇與應(ying)用(yong)好便攜式電(dian)子備(bei)(bei)中電(dian)池(chi)(chi)(chi)技術至關重要,值此本(ben)文(wen)將對此作(zuo)研討,并作(zuo)應(ying)用(yong)舉例分析.

1、關于細(xi)流充(chong)電(dian)、快(kuai)速充(chong)電(dian)和(he)穩定充(chong)電(dian)的電(dian)池充(chong)電(dian)算法

根(gen)據最終應用的(de)能(neng)量需求，一(yi)個(ge)電(dian)(dian)(dian)(dian)池(chi)(chi)組可(ke)能(neng)包(bao)含(han)最多4個(ge)鋰離(li)子或鋰聚(ju)合(he)物電(dian)(dian)(dian)(dian)池(chi)(chi)芯(xin),其配(pei)置(zhi)可(ke)有(you)多種(zhong)變化(hua)，同(tong)時帶(dai)有(you)一(yi)個(ge)主流的(de)電(dian)(dian)(dian)(dian)源適(shi)配(pei)器：直接的(de)適(shi)配(pei)器、USB接口(kou)或汽車充(chong)電(dian)(dian)(dian)(dian)器。除去電(dian)(dian)(dian)(dian)芯(xin)數量、電(dian)(dian)(dian)(dian)芯(xin)的(de)配(pei)置(zhi)或電(dian)(dian)(dian)(dian)源適(shi)配(pei)器類(lei)型上的(de)差別，這些電(dian)(dian)(dian)(dian)池(chi)(chi)組都有(you)同(tong)樣(yang)的(de)充(chong)電(dian)(dian)(dian)(dian)特(te)性。因此它(ta)們的(de)充(chong)電(dian)(dian)(dian)(dian)算(suan)法也一(yi)樣(yang)。鋰離(li)子與鋰聚(ju)合(he)物電(dian)(dian)(dian)(dian)池(chi)(chi)最好(hao)的(de)充(chong)電(dian)(dian)(dian)(dian)算(suan)法可(ke)以分為3個(ge)階段：細流充(chong)電(dian)(dian)(dian)(dian)、快速(su)充(chong)電(dian)(dian)(dian)(dian)和穩(wen)定充(chong)電(dian)(dian)(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)(wen)定(ding)(ding)電(dian)壓。在快速充(chong)電(dian)過(guo)程中(zhong)(zhong)，一旦電(dian)芯電(dian)壓達到4.2V，穩(wen)(wen)定(ding)(ding)電(dian)壓階段就開始了。這(zhe)(zhe)時(shi)可通過(guo)最小充(chong)電(dian)電(dian)流(liu)或(huo)定(ding)(ding)時(shi)器(qi)或(huo)這(zhe)(zhe)兩者的聯合來(lai)中(zhong)(zhong)斷充(chong)電(dian).當最小電(dian)流(liu)低(di)于大約0.07C時(shi)，可中(zhong)(zhong)斷充(chong)電(dian)。定(ding)(ding)時(shi)器(qi)則(ze)要靠一個預設的定(ding)(ding)時(shi)器(qi)來(lai)觸發(fa)中(zhong)(zhong)斷。

高級的電池充電器通常帶有附加(jia)的(de)(de)(de)安全功能。比如(ru)，如(ru)果電(dian)(dian)(dian)(dian)芯溫度超(chao)出給定(ding)窗口，通常是0℃--45℃，充電(dian)(dian)(dian)(dian)就(jiu)會暫(zan)停。除(chu)去某些非常低端(duan)的(de)(de)(de)設備，現在市面上的(de)(de)(de)鋰離(li)子／鋰聚合物電(dian)(dian)(dian)(dian)池充電(dian)(dian)(dian)(dian)方案都集成或(huo)是帶有外置的(de)(de)(de)元件，以便按照充電(dian)(dian)(dian)(dian)特(te)性進行充電(dian)(dian)(dian)(dian)，這不光是為了(le)取得更佳充電(dian)(dian)(dian)(dian)效果，同時也是為了(le)安全。

2、鋰離(li)子/聚(ju)合(he)物電(dian)池充(chong)電(dian)方案

鋰(li)離(li)子/聚合物電(dian)池的充電(dian)方案(an)對(dui)于不同(tong)數量的電(dian)芯(xin)、電(dian)芯(xin)配置以及(ji)電(dian)源類型還(huan)是不同(tong)的。目前主要有3種主要的充電(dian)方案(an)：線性(xing)，Buck(降壓(ya))開(kai)關和SEPIC(升(sheng)壓(ya)與(yu)降壓(ya))開(kai)關。

2.1線性方案

當充電(dian)器(qi)(qi)輸(shu)入電(dian)壓大于全充滿電(dian)芯(xin)加上充足(zu)凈(jing)空之(zhi)后的開路(lu)電(dian)壓時，最(zui)好用線(xian)性(xing)(xing)方(fang)(fang)(fang)案，特別是1.0C快(kuai)速充電(dian)電(dian)流不比1A大太多(duo)時。比如(ru)，MP3播放器(qi)(qi)通常只有一個(ge)電(dian)芯(xin)，容量從(cong)700到1500mAh不等，滿充開路(lu)電(dian)壓是4.2V。MP3播放機的電(dian)源(yuan)通常是AC／DC適(shi)配(pei)器(qi)(qi)或(huo)者是USB接口，其輸(shu)出是規則的5V；這(zhe)時，線(xian)性(xing)(xing)方(fang)(fang)(fang)案的充電(dian)器(qi)(qi)就(jiu)是最(zui)簡單、最(zui)有效率的方(fang)(fang)(fang)案。圖2所示為(wei)鋰(li)離子/聚合物電(dian)池充電(dian)方(fang)(fang)(fang)案線(xian)性(xing)(xing)方(fang)(fang)(fang)案,基(ji)本結構(gou)和線(xian)性(xing)(xing)電(dian)壓規整器(qi)(qi)一樣。

*線性方案(an)的(de)充電(dian)(dian)(dian)器(qi)應用例舉-雙(shuang)輸(shu)入Li+充電(dian)(dian)(dian)器(qi)及智能電(dian)(dian)(dian)源選擇器(qi)MAX8677A。MAX8677A是雙(shuang)輸(shu)入USB/AC適(shi)配器(qi)線性充電(dian)(dian)(dian)器(qi)，內置Smart Power Selector，用于由可(ke)充電(dian)(dian)(dian)單節(jie)Li+電(dian)(dian)(dian)池(chi)供(gong)電(dian)(dian)(dian)的(de)便攜式(shi)(shi)設備。該充電(dian)(dian)(dian)器(qi)集成了(le)電(dian)(dian)(dian)池(chi)和外(wai)部電(dian)(dian)(dian)源充電(dian)(dian)(dian)和切換負載所(suo)需(xu)的(de)全部功率開關，因此無需(xu)外(wai)部 MOSFET。MAX8677A理想用于便攜式(shi)(shi)設備，例如智能手(shou)機(ji)(ji)、PDA、便攜式(shi)(shi)多媒體播(bo)放器(qi)、GPS導(dao)航設備、數碼相機(ji)(ji)、以及數碼攝像機(ji)(ji)。

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)源(yuan)選擇器自動將電(dian)(dian)(dian)池(chi)切換到系(xi)統負載，使(shi)用(yong)系(xi)統未利用(yong)的(de)(de)(de)輸(shu)入(ru)電(dian)(dian)(dian)源(yuan)部分(fen)為電(dian)(dian)(dian)池(chi)充電(dian)(dian)(dian)，充分(fen)利用(yong)有(you)限的(de)(de)(de)USB和(he)(he)適配器輸(shu)入(ru)電(dian)(dian)(dian)源(yuan)。所有(you)需要的(de)(de)(de)電(dian)(dian)(dian)流(liu)檢測電(dian)(dian)(dian)路(lu)，包括集成的(de)(de)(de)功率開關，均集成于片上。DC輸(shu)入(ru)電(dian)(dian)(dian)流(liu)限最(zui)高可調節至2A，而(er)DC和(he)(he)USB輸(shu)入(ru)均可支持(chi)100mA、500mA、和(he)(he)USB掛起模式。充電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)可調節至高達1.5A，從而(er)支持(chi) 寬(kuan)范(fan)圍(wei)的(de)(de)(de)電(dian)(dian)(dian)池(chi)容性。MAX8677A的(de)(de)(de)其他(ta)特性包括熱調節、過壓(ya)保(bao)護、充電(dian)(dian)(dian)狀態和(he)(he)故(gu)障輸(shu)出、電(dian)(dian)(dian)源(yuan)好監視、電(dian)(dian)(dian)池(chi)熱敏電(dian)(dian)(dian)阻監視、以及充電(dian)(dian)(dian)定時器。MAX8677A采(cai)用(yong)節省空間的(de)(de)(de)、熱增強型、4mm×4mm、24引腳的(de)(de)(de)TQFN封裝，規定工(gong)作于擴(kuo)展級(ji)溫度(du)范(fan)圍(wei)(-40～+85℃)。

2.2 Buck(降(jiang)壓)開關方案

當1.0C充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)的電(dian)(dian)(dian)(dian)(dian)(dian)流大于(yu)1A，或者(zhe)輸(shu)入(ru)(ru)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)比電(dian)(dian)(dian)(dian)(dian)(dian)芯的全(quan)充(chong)滿開(kai)路(lu)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)高很(hen)多(duo)時，Buck或者(zhe)降(jiang)壓(ya)(ya)方案就是(shi)一個更好(hao)的選擇。比如，在基于(yu)硬(ying)盤的PMP中，通(tong)常使用單芯鋰離子電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)，全(quan)充(chong)滿開(kai)路(lu)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)是(shi)4.2V，容量從(cong)1200到2400mAh不等(deng)。而現(xian)在PMP通(tong)常是(shi)用汽(qi)車套件來(lai)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)，它的輸(shu)出電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)在9V到16V之間。在輸(shu)入(ru)(ru)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)和(he)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)之間比較高的電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)差(最小4.8V)會(hui)讓(rang)線性方案降(jiang)低效率。這種低效率，加上大于(yu)1.2A的1C快速充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流，會(hui)產生嚴(yan)重的散熱問題(ti)。為避免這種情況，就要(yao)采用Buck方案。圖(tu)(tu)3為鋰電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)器方案示意圖(tu)(tu),基本結構(gou)同Buck(降(jiang)壓(ya)(ya))開(kai)關電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)調節器完全(quan)相同。

2.3 SEPIC(升壓與降壓)開關方案(an)

在(zai)某些使(shi)用3個甚至4個鋰(li)離子／聚合物(wu)電(dian)(dian)(dian)(dian)(dian)芯(xin)(xin)串聯的設(she)備中(zhong)，充(chong)電(dian)(dian)(dian)(dian)(dian)器(qi)的輸(shu)(shu)(shu)入電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)就(jiu)不(bu)(bu)總是(shi)(shi)大于(yu)(yu)電(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)。比如，筆記本電(dian)(dian)(dian)(dian)(dian)腦使(shi)用3芯(xin)(xin)鋰(li)離子電(dian)(dian)(dian)(dian)(dian)池組(zu)，滿充(chong)開路電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)是(shi)(shi)12．6V(4．2V x3)，容(rong)量從1800mAh到(dao)3600mAh。輸(shu)(shu)(shu)入電(dian)(dian)(dian)(dian)(dian)源要么是(shi)(shi)輸(shu)(shu)(shu)出(chu)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)1 6V的AC／DC適配器(qi)，要么是(shi)(shi)汽車套件，輸(shu)(shu)(shu)出(chu)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)在(zai)9V到(dao)16V之間。很顯(xian)然地(di)，線性和(he)Buck方案都不(bu)(bu)能為這組(zu)電(dian)(dian)(dian)(dian)(dian)池組(zu)充(chong)電(dian)(dian)(dian)(dian)(dian)。這就(jiu)要用上SEPIC方案，它(ta)能在(zai)輸(shu)(shu)(shu)出(chu)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)高于(yu)(yu)電(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)時(shi)工作，也能在(zai)輸(shu)(shu)(shu)出(chu)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)低于(yu)(yu)電(dian)(dian)(dian)(dian)(dian)池時(shi)工作。

3、電量檢測算法

許(xu)多可(ke)攜式產(chan)品都利用(yong)電(dian)(dian)(dian)壓(ya)測量值(zhi)來估計電(dian)(dian)(dian)池(chi)剩馀(yu)電(dian)(dian)(dian)量，但是電(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)壓(ya)與剩馀(yu)電(dian)(dian)(dian)量的(de)(de)(de)關系卻會(hui)隨著放(fang)電(dian)(dian)(dian)率、溫度和(he)電(dian)(dian)(dian)池(chi)老化程度而改變，使(shi)這種方法的(de)(de)(de)誤差(cha)率最高可(ke)達50％。市(shi)場對(dui)使(shi)用(yong)時(shi)間更長的(de)(de)(de)產(chan)品需求不(bu)斷增強，因此系統設(she)計人員需要更加精確的(de)(de)(de)解決(jue)方案(an)。使(shi)用(yong)電(dian)(dian)(dian)量檢測計吧來測量電(dian)(dian)(dian)池(chi)充(chong)人或消(xiao)耗的(de)(de)(de)電(dian)(dian)(dian)量，將能夠在很寬(kuan)的(de)(de)(de)應用(yong)電(dian)(dian)(dian)源級別范圍內(nei)提供更精確的(de)(de)(de)電(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)量估測。

3.1電(dian)量檢測算法應用舉例之一,功能(neng)完整的單＼雙(shuang)電(dian)池(chi)便攜式應用電(dian)池(chi)組設計

*電(dian)(dian)(dian)(dian)(dian)量(liang)(liang)(liang)檢(jian)(jian)(jian)測(ce)(ce)(ce)(ce)(ce)(ce)原理.較好的(de)電(dian)(dian)(dian)(dian)(dian)量(liang)(liang)(liang)檢(jian)(jian)(jian)測(ce)(ce)(ce)(ce)(ce)(ce)計(ji)(ji)(ji)至少要(yao)具備電(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(wen)度和電(dian)(dian)(dian)(dian)(dian)流(liu)、測(ce)(ce)(ce)(ce)(ce)(ce)量(liang)(liang)(liang)方(fang)法(fa)；一(yi)個(ge)微處(chu)理9a；和一(yi)套(tao)及業經驗證的(de)電(dian)(dian)(dian)(dian)(dian)量(liang)(liang)(liang)檢(jian)(jian)(jian)測(ce)(ce)(ce)(ce)(ce)(ce)算(suan)法(fa)。bq2650x及bq27x00是功能(neng)完整的(de)電(dian)(dian)(dian)(dian)(dian)量(liang)(liang)(liang)檢(jian)(jian)(jian)測(ce)(ce)(ce)(ce)(ce)(ce)計(ji)(ji)(ji)，具有一(yi)個(ge)測(ce)(ce)(ce)(ce)(ce)(ce)量(liang)(liang)(liang)電(dian)(dian)(dian)(dian)(dian)壓(ya)與溫(wen)度的(de)模數轉換器(qi)(ADC)和一(yi)個(ge)測(ce)(ce)(ce)(ce)(ce)(ce)量(liang)(liang)(liang)電(dian)(dian)(dian)(dian)(dian)流(liu)與充電(dian)(dian)(dian)(dian)(dian)感(gan)測(ce)(ce)(ce)(ce)(ce)(ce)的(de)模數轉換器(qi)。這些電(dian)(dian)(dian)(dian)(dian)量(liang)(liang)(liang)檢(jian)(jian)(jian)測(ce)(ce)(ce)(ce)(ce)(ce)計(ji)(ji)(ji)還(huan)具有一(yi)個(ge)微處(chu)理器(qi)，負(fu)(fu)責(ze)執行德(de)州儀器(qi)的(de)電(dian)(dian)(dian)(dian)(dian)量(liang)(liang)(liang)檢(jian)(jian)(jian)測(ce)(ce)(ce)(ce)(ce)(ce)算(suan)法(fa)。這些演算(suan)法(fa)會(hui)補(bu)償鋰離子電(dian)(dian)(dian)(dian)(dian)池(chi)的(de)自(zi)放電(dian)(dian)(dian)(dian)(dian)、老化、溫(wen)度和放電(dian)(dian)(dian)(dian)(dian)率等(deng)因素。晶片(pian)內含(han)微處(chu)理器(qi)為主(zhu)機系(xi)統(tong)處(chu)理器(qi)省下這些計(ji)(ji)(ji)算(suan)負(fu)(fu)擔(dan).電(dian)(dian)(dian)(dian)(dian)量(liang)(liang)(liang)檢(jian)(jian)(jian)測(ce)(ce)(ce)(ce)(ce)(ce)計(ji)(ji)(ji)能(neng)夠提(ti)供(gong)剩余電(dian)(dian)(dian)(dian)(dian)量(liang)(liang)(liang)狀態等(deng)信(xin)(xin)息，bq27x00系(xi)列產品還(huan)提(ti)供(gong)剩余可運行時(shi)間(jian)(Run Time to Empty)主(zhu)機可隨時(shi)向(xiang)電(dian)(dian)(dian)(dian)(dian)量(liang)(liang)(liang)檢(jian)(jian)(jian)測(ce)(ce)(ce)(ce)(ce)(ce)計(ji)(ji)(ji)查詢這些信(xin)(xin)息，再透過LED指(zhi)示(shi)燈或屏幕(mu)顯示(shi)將電(dian)(dian)(dian)(dian)(dian)池(chi)信(xin)(xin)息通(tong)知用戶(hu)。電(dian)(dian)(dian)(dian)(dian)量(liang)(liang)(liang)檢(jian)(jian)(jian)測(ce)(ce)(ce)(ce)(ce)(ce)計(ji)(ji)(ji)的(de)使用非常方(fang)便，系(xi)統(tong)處(chu)理器(qi)僅需要(yao)配置(zhi)12C或HDQ通(tong)信(xin)(xin)驅動器(qi)即(ji)可。

*電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)組電(dian)(dian)(dian)(dian)(dian)(dian)路描述.圖4(a)為可(ke)(ke)選用(yong)(yong)具有鑒定功能(neng)(neng)IC的典(dian)型的電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)組應用(yong)(yong)電(dian)(dian)(dian)(dian)(dian)(dian)路。根據所使用(yong)(yong)電(dian)(dian)(dian)(dian)(dian)(dian)量檢(jian)(jian)測(ce)(ce)計(ji)IC的不(bu)同，電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)組至少需要有三到四個外部終(zhong)端(duan)。VCC及(ji)(ji)BAT引(yin)腳會(hui)連到電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)，以便(bian)為，C供(gong)電(dian)(dian)(dian)(dian)(dian)(dian)及(ji)(ji)測(ce)(ce)量電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)。電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)接(jie)地端(duan)連接(jie)了一個電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)值(zhi)較(jiao)小(xiao)的檢(jian)(jian)測(ce)(ce)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)器，讓(rang)電(dian)(dian)(dian)(dian)(dian)(dian)量檢(jian)(jian)測(ce)(ce)計(ji)的高(gao)阻(zu)(zu)(zu)抗(kang)SRP及(ji)(ji)SRN輸入(ru)端(duan)能(neng)(neng)夠監控感(gan)測(ce)(ce)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)兩端(duan)的電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)。通過流(liu)(liu)經檢(jian)(jian)測(ce)(ce)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)器的電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)可(ke)(ke)用(yong)(yong)來判(pan)斷電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)充入(ru)或(huo)釋放(fang)的電(dian)(dian)(dian)(dian)(dian)(dian)量。設(she)計(ji)人員(yuan)選擇(ze)檢(jian)(jian)測(ce)(ce)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)值(zhi)時必須考慮電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)兩端(duan)的電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)不(bu)能(neng)(neng)超過100 mV，過低的電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)值(zhi)可(ke)(ke)能(neng)(neng)會(hui)在電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)較(jiao)小(xiao)時產(chan)生誤差。電(dian)(dian)(dian)(dian)(dian)(dian)路板(ban)布局必須確保(bao)從SRP及(ji)(ji)SRN到檢(jian)(jian)測(ce)(ce)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)器的連接(jie)要盡可(ke)(ke)能(neng)(neng)靠(kao)近感(gan)測(ce)(ce)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)端(duan)；換言之，它們應該是采用(yong)(yong)Kelvin連線。

HDQ引腳(jiao)需要外(wai)部上拉(la)電阻器，該電阻應位于(yu)主(zhu)機或主(zhu)應用(yong)端(duan)，這(zhe)樣電量檢(jian)測計才能在(zai)電池組與(yu)便(bian)攜(xie)式(shi)設備連接斷開時啟用(yong)睡眠功能。建議(yi)上拉(la)電阻值選用(yong)10 kΩ。

*電(dian)(dian)(dian)(dian)(dian)池(chi)組鑒(jian)定(ding)(ding)。價格低(di)廉(lian)的(de)偽冒電(dian)(dian)(dian)(dian)(dian)池(chi)的(de)問題日(ri)益(yi)嚴重(zhong)，這(zhe)些電(dian)(dian)(dian)(dian)(dian)池(chi)可能不包含(han)OEM廠商要(yao)求的(de)安全保(bao)護電(dian)(dian)(dian)(dian)(dian)路。所(suo)以，真品電(dian)(dian)(dian)(dian)(dian)池(chi)組可包含(han)圖4(a)所(suo)示的(de)鑒(jian)定(ding)(ding)電(dian)(dian)(dian)(dian)(dian)路。當(dang)要(yao)鑒(jian)定(ding)(ding)電(dian)(dian)(dian)(dian)(dian)池(chi)時(shi)，主機(ji)向含(han)有(you)IC(bq26150，作用是循環冗(rong)余校驗(CRC))的(de)電(dian)(dian)(dian)(dian)(dian)池(chi)組發(fa)出(chu)一(yi)(yi)個詢問值(zhi)(challenge)，電(dian)(dian)(dian)(dian)(dian)池(chi)組所(suo)含(han)的(de)CRC會根據這(zhe)個詢問值(zhi)和，IC中內建的(de)CRC多(duo)項式計(ji)(ji)算這(zhe)個CRC值(zhi)。CRC是基于(yu)主機(ji)的(de)查詢命(ming)令與(yu)IC中秘密定(ding)(ding)義的(de)CRC多(duo)項式完(wan)成(cheng)的(de)，主機(ji)也會進行CRC值(zhi)計(ji)(ji)算井與(yu)電(dian)(dian)(dian)(dian)(dian)池(chi)組的(de)計(ji)(ji)算結果比(bi)較以確(que)定(ding)(ding)鑒(jian)定(ding)(ding)是否(fou)成(cheng)功。一(yi)(yi)旦(dan)電(dian)(dian)(dian)(dian)(dian)池(chi)通過鑒(jian)定(ding)(ding)，bq26150則會發(fa)出(chu)指令以確(que)保(bao)主機(ji)與(yu)電(dian)(dian)(dian)(dian)(dian)量(liang)檢測計(ji)(ji)之間的(de)資料線(xian)路通訊(xun)正常。當(dang)電(dian)(dian)(dian)(dian)(dian)池(chi)連(lian)接中斷或重(zhong)新連(lian)接時(shi)，整個鑒(jian)定(ding)(ding)過程(cheng)將重(zhong)復(fu)一(yi)(yi)次(ci)。

3.2電量檢測算法(fa)應用舉例之二,能適用于各種(zhong)通用電量計的新型IC.

當今(jin)不少制造廠商(shang)可提供(gong)種類豐富的電(dian)(dian)量(liang)(liang)計(ji)(ji)IC,，用(yong)(yong)戶可從(cong)中(zhong)選(xuan)取(qu)合適的功能器件(jian)，以優化產品(pin)的性價比。利用(yong)(yong)電(dian)(dian)量(liang)(liang)計(ji)(ji)貯測量(liang)(liang)的電(dian)(dian)池參數，這種分離(li)(li)式架構允許(xu)用(yong)(yong)戶在(zai)主機內定制電(dian)(dian)量(liang)(liang)計(ji)(ji)量(liang)(liang)算法．從(cong)而(er)省去電(dian)(dian)池組內嵌處理(li)器的成本。值(zhi)此以Dallase semicconductor公(gong)司名為例的DS2762芯片作典(dian)型分析. 一(yi)新型分離(li)(li)式電(dian)(dian)量(liang)(liang)計(ji)(ji)IC,其結構見圖5(a)所(suo)示(shi).

*DS2762應用特(te)征

DS2762是(shi)一款單節鋰(li)電(dian)(dian)(dian)池電(dian)(dian)(dian)量(liang)(liang)計與保護(hu)(hu)電(dian)(dian)(dian)路(lu)(lu)，集(ji)(ji)成(cheng)(cheng)于一片(pian)微小(xiao)的(de)(de)(de)(de)2.46mm× 2.74mm倒(dao)裝片(pian)封裝。由于內部集(ji)(ji)成(cheng)(cheng)了用于電(dian)(dian)(dian)量(liang)(liang)檢測的(de)(de)(de)(de)高精密(mi)電(dian)(dian)(dian)阻，該款器(qi)件非常節省空間(jian)。它所具有(you)的(de)(de)(de)(de)小(xiao)尺寸和無可比擬(ni)的(de)(de)(de)(de)高集(ji)(ji)成(cheng)(cheng)度，對于移動(dong)電(dian)(dian)(dian)話電(dian)(dian)(dian)池組及其它類似的(de)(de)(de)(de)手持(chi)產品，如PDA等，都(dou)非常理(li)想。集(ji)(ji)成(cheng)(cheng)的(de)(de)(de)(de)保護(hu)(hu)電(dian)(dian)(dian)路(lu)(lu)連續地監視電(dian)(dian)(dian)池的(de)(de)(de)(de)過壓(ya)、欠壓(ya)和過流(liu)故障(充(chong)電(dian)(dian)(dian)或放電(dian)(dian)(dian)期間(jian))。不同(tong)于獨(du)立的(de)(de)(de)(de)保護(hu)(hu)IC，DS2762允許(xu)主處理(li)器(qi)監視/控制(zhi)保護(hu)(hu)FET的(de)(de)(de)(de)導通狀態，這樣，可以通過DS2762的(de)(de)(de)(de)保護(hu)(hu)電(dian)(dian)(dian)路(lu)(lu)實現系統電(dian)(dian)(dian)源控制(zhi)。DS2762也可以充(chong)電(dian)(dian)(dian)一個已深(shen)度消(xiao)耗的(de)(de)(de)(de)電(dian)(dian)(dian)池，當電(dian)(dian)(dian)池電(dian)(dian)(dian)壓(ya)不足3V時，提供一條(tiao)限(xian)制(zhi)電(dian)(dian)(dian)流(liu)的(de)(de)(de)(de)恢復充(chong)電(dian)(dian)(dian)路(lu)(lu)徑(jing)。

DS2762能夠精確監視(shi)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)(dian)流(liu)、電(dian)(dian)(dian)(dian)(dian)壓(ya)和溫度(du)，其動(dong)態(tai)范圍與分辨率滿足任何通(tong)行(xing)的(de)(de)移動(dong)通(tong)信產(chan)品的(de)(de)測(ce)(ce)試(shi)標準(zhun)。測(ce)(ce)得的(de)(de)電(dian)(dian)(dian)(dian)(dian)流(liu)對內部產(chan)生的(de)(de)時(shi)(shi)基進(jin)行(xing)積分，實現電(dian)(dian)(dian)(dian)(dian)量計(ji)量。通(tong)過(guo)實時(shi)(shi)、連(lian)續的(de)(de)自(zi)動(dong)失(shi)調糾正(zheng)，電(dian)(dian)(dian)(dian)(dian)量計(ji)量的(de)(de)精度(du)得以提(ti)高(gao)。內置的(de)(de)檢測(ce)(ce)電(dian)(dian)(dian)(dian)(dian)阻(zu)消除了(le)因制造(zao)工藝和溫度(du)而造(zao)成的(de)(de)電(dian)(dian)(dian)(dian)(dian)阻(zu)變化，進(jin)一步提(ti)高(gao)了(le)電(dian)(dian)(dian)(dian)(dian)量計(ji)的(de)(de)精度(du)。重要數據(ju)保(bao)存(cun)于32字節、可加(jia)鎖(suo)的(de)(de)EEPROM；16字節的(de)(de)SRAM用于保(bao)存(cun)動(dong)態(tai)數據(ju)。與DS2762的(de)(de)所有通(tong)信均通(tong)過(guo)1-Wire、多節點通(tong)信接口進(jin)行(xing)，最大限度(du)減少了(le)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)組(zu)與主機的(de)(de)連(lian)線。其主要特征(zheng)為；單節鋰電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)保(bao)護器；高(gao)精度(du)電(dian)(dian)(dian)(dian)(dian)流(liu)(電(dian)(dian)(dian)(dian)(dian)量計(ji)量)、電(dian)(dian)(dian)(dian)(dian)壓(ya)和溫度(du)測(ce)(ce)量；可選的(de)(de)集(ji)成25mΩ檢測(ce)(ce)電(dian)(dian)(dian)(dian)(dian)阻(zu)，每(mei)個DS2762經過(guo)單獨微調；0V電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)恢(hui)復充電(dian)(dian)(dian)(dian)(dian)；32字節可加(jia)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(dian)(dian)池組電(dian)(dian)源(yuan)管理，并通過保護FET實現系統電(dian)(dian)源(yuan)控(kong)制；休眠模式下(xia)電(dian)(dian)源(yuan)電(dian)(dian)流(liu)僅2?A(最大);工(gong)作模式下(xia)電(dian)(dian)源(yuan)電(dian)(dian)流(liu)為(wei)90?A(最大);2.46mm×2.74mm倒裝片封裝或16引腳下(xia)SSOP封裝，兩者均(jun)可選擇帶(dai)或不帶(dai)檢測電(dian)(dian)阻(zu);復(fu)具有備(bei)有評估(gu)板.

4、結論

應用好便攜(xie)式電(dian)(dian)子(zi)設備的(de)電(dian)(dian)池(chi)技(ji)術(shu)是(shi)選擇(ze)鋰離子(zi)電(dian)(dian)池(chi)和鋰聚合物電(dian)(dian)池(chi)及其充電(dian)(dian)器的(de)基礎.之于(yu)如何(he)正(zheng)確(que)選擇(ze),還必須視便攜(xie)式電(dian)(dian)子(zi)備的(de)具體(ti)要求而定。