隨著大容量高耗能的移動電子產品的問世，便攜式移動電源也隨之(zhi)發展(zhan)而(er)來，而(er)能(neng)讓用戶清楚的(de)(de)(de)知道(dao)設備剩余電(dian)(dian)(dian)量(liang)，就需(xu)要(yao)(yao)有(you)相應的(de)(de)(de)電(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)量(liang)檢(jian)測電(dian)(dian)(dian)路(lu)和電(dian)(dian)(dian)子元(yuan)器件，便攜式(shi)移動(dong)(dong)電(dian)(dian)(dian)源(yuan)本身是(shi)由(you)大容量(liang)的(de)(de)(de)鋰電(dian)(dian)(dian)池(chi)(chi)和內(nei)部(bu)控(kong)(kong)制(zhi)電(dian)(dian)(dian)路(lu)構成，控(kong)(kong)制(zhi)電(dian)(dian)(dian)路(lu)又分為兩(liang)種(zhong)，一種(zhong)為簡單的(de)(de)(de)升(sheng)壓(ya)控(kong)(kong)制(zhi)芯片與(yu)單片機(ji)結合(he)組成，另一種(zhong)則為專(zhuan)用控(kong)(kong)制(zhi)芯片形成的(de)(de)(de)集充電(dian)(dian)(dian)、升(sheng)壓(ya)、過流(liu)、過壓(ya)以及短路(lu)保護(hu)等為一體(ti)的(de)(de)(de)綜合(he)性電(dian)(dian)(dian)路(lu)系(xi)統，而(er)這(zhe)種(zhong)方案(an)也正以成本更低，控(kong)(kong)制(zhi)更完備，系(xi)統更安(an)全(quan)等優勢越來越受(shou)到(dao)消費者青睞。在各種(zhong)便攜式(shi)移動(dong)(dong)電(dian)(dian)(dian)源(yuan)專(zhuan)用控(kong)(kong)制(zhi)芯片的(de)(de)(de)控(kong)(kong)制(zhi)系(xi)統中(zhong)有(you)重要(yao)(yao)的(de)(de)(de)一個控(kong)(kong)制(zhi)環節(jie)，那(nei)就是(shi)便攜式(shi)移動(dong)(dong)電(dian)(dian)(dian)源(yuan)的(de)(de)(de)內(nei)部(bu)鋰電(dian)(dian)(dian)池(chi)(chi)的(de)(de)(de)電(dian)(dian)(dian)量(liang)指示，這(zhe)種(zhong)指示剩余電(dian)(dian)(dian)量(liang)的(de)(de)(de)功能(neng)需(xu)要(yao)(yao)有(you)較(jiao)為準確的(de)(de)(de)電(dian)(dian)(dian)量(liang)檢(jian)測方法(fa)。

1、目前通用的電量顯示方法

目前通(tong)用的(de)顯(xian)示(shi)方(fang)(fang)式(shi)都是以四個LED燈的(de)顯(xian)示(shi)方(fang)(fang)案為主流，故本(ben)文也采用四個LED的(de)顯(xian)示(shi)方(fang)(fang)式(shi)來舉例說明。

通(tong)用做(zuo)法(fa)是將移動電(dian)(dian)(dian)(dian)(dian)源的(de)(de)(de)總(zong)(zong)(zong)電(dian)(dian)(dian)(dian)(dian)量(liang)(liang)劃(hua)分(fen)(fen)為(wei)四部分(fen)(fen)，25%，50%，75%，100%。分(fen)(fen)別(bie)用四個LED燈來顯示。最早出現的(de)(de)(de)移動電(dian)(dian)(dian)(dian)(dian)源中的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)量(liang)(liang)指示，基(ji)本都是以電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)壓(ya)的(de)(de)(de)等(deng)分(fen)(fen)來簡單(dan)判斷電(dian)(dian)(dian)(dian)(dian)量(liang)(liang)多少的(de)(de)(de)。例(li)如將電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)壓(ya)分(fen)(fen)為(wei)3.3V，3.6V，3.9V，4.2V，并以此為(wei)劃(hua)分(fen)(fen)25%，50%，75%，100%，就是認為(wei)在(zai)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)壓(ya)為(wei)4.2V～3.9V時(shi)(shi)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)量(liang)(liang)為(wei)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)總(zong)(zong)(zong)電(dian)(dian)(dian)(dian)(dian)量(liang)(liang)的(de)(de)(de)100%，當電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)壓(ya)在(zai)3.9V～3.6V時(shi)(shi)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)量(liang)(liang)為(wei)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)總(zong)(zong)(zong)電(dian)(dian)(dian)(dian)(dian)量(liang)(liang)的(de)(de)(de)75%，電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)壓(ya)在(zai)3.9V～3.6V時(shi)(shi)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)量(liang)(liang)為(wei)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)總(zong)(zong)(zong)電(dian)(dian)(dian)(dian)(dian)量(liang)(liang)的(de)(de)(de)50%，當電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)壓(ya)在(zai)3.6V～3.3V時(shi)(shi)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)量(liang)(liang)為(wei)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)總(zong)(zong)(zong)電(dian)(dian)(dian)(dian)(dian)量(liang)(liang)的(de)(de)(de)25%。

實(shi)際(ji)上，以(yi)上這種劃分(fen)(fen)并不(bu)準確(que)，因為電(dian)(dian)(dian)(dian)池(chi)(chi)的(de)充放電(dian)(dian)(dian)(dian)時間與電(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)壓(ya)不(bu)是簡單的(de)線性關(guan)系。這樣會導致電(dian)(dian)(dian)(dian)量劃分(fen)(fen)不(bu)均勻，可能在(zai)指示50%～75%部(bu)分(fen)(fen)實(shi)際(ji)卻占據(ju)了電(dian)(dian)(dian)(dian)池(chi)(chi)60%的(de)電(dian)(dian)(dian)(dian)量。根(gen)據(ju)專門對電(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)量的(de)測試，事(shi)實(shi)情況也(ye)確(que)實(shi)如此。根(gen)據(ju)測試結果，電(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)量最(zui)多也(ye)就是電(dian)(dian)(dian)(dian)池(chi)(chi)能供電(dian)(dian)(dian)(dian)時間最(zui)長(chang)的(de)電(dian)(dian)(dian)(dian)壓(ya)段是在(zai)3.7V～3.9V，基本(ben)占一半以(yi)上的(de)總電(dian)(dian)(dian)(dian)量。，以(yi)單節2500mah，輸出1A電(dian)(dian)(dian)(dian)流為例，電(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)壓(ya)在(zai)3.7V～3.9V時放電(dian)(dian)(dian)(dian)時間大約80分(fen)(fen)鐘左(zuo)右。

為(wei)了解決這個問題，工程師對(dui)電(dian)(dian)池(chi)電(dian)(dian)壓的(de)(de)(de)劃分做了調(diao)整， 不在以電(dian)(dian)壓等分的(de)(de)(de)形(xing)式(shi)作為(wei)電(dian)(dian)量(liang)(liang)多少的(de)(de)(de)參考，而(er)以電(dian)(dian)池(chi)充電(dian)(dian)或者放(fang)電(dian)(dian)的(de)(de)(de)時(shi)間(jian)等分點(dian)所(suo)對(dui)應的(de)(de)(de)電(dian)(dian)壓為(wei)參考。例如電(dian)(dian)池(chi)放(fang)電(dian)(dian)時(shi)，電(dian)(dian)壓由4.2V降到3.98V用了四(si)分之一的(de)(de)(de)總容量(liang)(liang)時(shi)間(jian)，那就以3.98V作為(wei)一個參考電(dian)(dian)壓門檻(jian)，以此類推。這基(ji)本形(xing)成(cheng)了目前通用的(de)(de)(de)移(yi)動電(dian)(dian)源控(kong)制芯片的(de)(de)(de)電(dian)(dian)量(liang)(liang)檢測方(fang)式(shi)。

上述方式存在(zai)(zai)兩個問題(ti)。一是由于電(dian)(dian)池(chi)(chi)內阻(zu)的存在(zai)(zai)使(shi)得(de)在(zai)(zai)實(shi)際采樣到(dao)的電(dian)(dian)池(chi)(chi)電(dian)(dian)壓并非電(dian)(dian)池(chi)(chi)真實(shi)電(dian)(dian)壓，并且系統板上電(dian)(dian)池(chi)(chi)端導(dao)線電(dian)(dian)阻(zu)以(yi)及保護IC開關管導(dao)通(tong)電(dian)(dian)阻(zu)都(dou)(dou)將(jiang)作為電(dian)(dian)池(chi)(chi)內阻(zu)的形式疊加上去，這是一個相(xiang)當大的量級，一般都(dou)(dou)有將(jiang)近100毫歐。

2 帶有(you)內阻補償的電量(liang)檢測方案(an)

更(geng)進一(yi)步的解決方(fang)案為，在以電(dian)(dian)池(chi)電(dian)(dian)壓為參(can)考(kao)的同(tong)時，同(tong)步采集(ji)電(dian)(dian)池(chi)電(dian)(dian)流(liu)，根據(ju)采集(ji)到的電(dian)(dian)流(liu)的大(da)小來計算等效(xiao)電(dian)(dian)池(chi)內阻(zu)（包括(kuo)導(dao)線電(dian)(dian)阻(zu)和保護IC的開關導(dao)通電(dian)(dian)阻(zu)），然后將(jiang)這個內阻(zu)產生的額外壓降疊加到電(dian)(dian)池(chi)容量參(can)考(kao)電(dian)(dian)壓上，這樣(yang)就更(geng)好的改善了(le)(le)電(dian)(dian)池(chi)電(dian)(dian)量的檢(jian)測精度，使得檢(jian)測方(fang)式更(geng)進了(le)(le)一(yi)步。

但這(zhe)種改進(jin)(jin)后本方案人也是有一(yi)定的(de)(de)問題的(de)(de)。對(dui)于不同電(dian)池容量和移動電(dian)源生產廠家而(er)言很(hen)難保證(zheng)這(zhe)個等效電(dian)阻是能有效的(de)(de)補償(chang)，因(yin)此需要(yao)每一(yi)批(pi)次(ci)進(jin)(jin)行調整(zheng)補償(chang)值(zhi)的(de)(de)大小，這(zhe)對(dui)于控制(zhi)芯片上意味著還需要(yao)一(yi)個專門(men)的(de)(de)控制(zhi)電(dian)阻補償(chang)的(de)(de)調整(zheng)引(yin)腳。

另外在上述(shu)的(de)(de)兩種方(fang)案中都還存在電(dian)(dian)池(chi)充(chong)電(dian)(dian)和放電(dian)(dian)參考門檻不一致(zhi)的(de)(de)情況。這樣(yang)充(chong)電(dian)(dian)和升(sheng)壓(ya)(ya)判斷參考電(dian)(dian)壓(ya)(ya)不同會(hui)導致(zhi)在充(chong)電(dian)(dian)和升(sheng)壓(ya)(ya)互轉(zhuan)的(de)(de)時候看(kan)到不同狀態(tai)剩余電(dian)(dian)量不一樣(yang)的(de)(de)問(wen)(wen)題。例如：在充(chong)電(dian)(dian)時顯示為75%的(de)(de)電(dian)(dian)量，結果轉(zhuan)換為升(sheng)壓(ya)(ya)輸出時變為50%的(de)(de)電(dian)(dian)量的(de)(de)現象。當(dang)然(ran)這都是電(dian)(dian)池(chi)的(de)(de)充(chong)放電(dian)(dian)曲(qu)線不同造成的(de)(de)問(wen)(wen)題。

目(mu)前(qian)認為(wei)較好的(de)的(de)電(dian)(dian)池電(dian)(dian)量(liang)方式(shi)是電(dian)(dian)量(liang)計芯片中所采用的(de)方式(shi)。但電(dian)(dian)量(liang)計芯片的(de)設(she)計較為(wei)復雜，在移動電(dian)(dian)源目(mu)前(qian)的(de)生產成本(ben)上不容(rong)易將(jiang)電(dian)(dian)量(liang)計的(de)電(dian)(dian)路設(she)計加入進去(qu)，它需(xu)要(yao)mcu，大量(liang)的(de)數字(zi)處理，以及復雜的(de)算法(fa)等。而本(ben)文提出了一(yi)個既(ji)不需(xu)要(yao)太(tai)復雜的(de)數字(zi)電(dian)(dian)路但卻(que)能較好的(de)提高電(dian)(dian)池電(dian)(dian)量(liang)檢測的(de)方式(shi)，具有(you)相當的(de)可行(xing)性。

3 電荷計量檢測(ce)電量方案的分析(xi)與設計

本論文的(de)改進方法為電(dian)(dian)荷(he)計(ji)量(liang)的(de)方法，這與電(dian)(dian)量(liang)計(ji)芯片(pian)中(zhong)的(de)設計(ji)思想有些類似，但設計(ji)簡潔，在(zai)移動電(dian)(dian)源控制芯片(pian)中(zhong)易于實現。