思旺電子開發出一款為鋰電池充電器 (萬能充/座充)設計的配套LCD/LED驅動電路SE9120,在顯示電池電量的同時還能顯示充電進度和電池充飽狀態。下文(wen)將重點介(jie)紹SE9120的主要技術特點。

　　SE9120主要功能(neng)

　　SE9120主要功能包括電池電量檢測及充電進度顯示功能，能夠通過電路內部自動判斷電池極性，自動切換到電池正確的極性，解決用戶在裝載電池時需要人工判斷電池極性的問題。在檢測電池極性的同時，SE9120能夠檢測電池的電量，同時SE9120是第一款創新的用4位分段顯示的方法，驅動4柱LCD屏，使用戶可以查看電池電量的集成電路。

　　SE9120是一款(kuan)高智能(neng)的數(shu)模(mo)混合(he)電(dian)(dian)路，該(gai)芯片采用(yong)數(shu)模(mo)混合(he)方式，通過4位柱(zhu)狀顯(xian)(xian)示(shi)LCD屏或LED屏，在顯(xian)(xian)示(shi)電(dian)(dian)池電(dian)(dian)量的同時還(huan)能(neng)顯(xian)(xian)示(shi)充電(dian)(dian)進度和電(dian)(dian)池充飽狀態。SE9120的內部結構(gou)如圖1所示(shi)。主要包括五大(da)功能(neng)模(mo)塊(kuai)：基準電(dian)(dian)壓(ya)單(dan)元;電(dian)(dian)池電(dian)(dian)量檢測單(dan)元;顯(xian)(xian)示(shi)邏輯單(dan)元;LCD驅(qu)動單(dan)元;LED背光驅(qu)動單(dan)元。

　　電池(chi)電量檢測單(dan)元

　　SE9120通過電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)電(dian)(dian)(dian)(dian)量(liang)(liang)檢測單(dan)(dan)(dan)元(yuan)中的(de)(de)B1電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)電(dian)(dian)(dian)(dian)量(liang)(liang)信息單(dan)(dan)(dan)元(yuan)，探測到(dao)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)兩端的(de)(de)電(dian)(dian)(dian)(dian)壓(ya)和電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)的(de)(de)極(ji)性(xing)(xing)，然(ran)(ran)后自動轉(zhuan)(zhuan)換電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)極(ji)性(xing)(xing)，并將(jiang)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)的(de)(de)電(dian)(dian)(dian)(dian)壓(ya)傳(chuan)送給B2模數(shu)轉(zhuan)(zhuan)換單(dan)(dan)(dan)元(yuan)，然(ran)(ran)后模數(shu)控制單(dan)(dan)(dan)元(yuan)將(jiang)這(zhe)個電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)電(dian)(dian)(dian)(dian)量(liang)(liang)的(de)(de)信號(hao)，與內建精準的(de)(de)基(ji)準電(dian)(dian)(dian)(dian)壓(ya)單(dan)(dan)(dan)元(yuan)提供的(de)(de)參考電(dian)(dian)(dian)(dian)壓(ya)進(jin)行(xing)比較，從(cong)而(er)將(jiang)模擬的(de)(de)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)電(dian)(dian)(dian)(dian)量(liang)(liang)信號(hao)，轉(zhuan)(zhuan)換為數(shu)字信號(hao)，提供給后級電(dian)(dian)(dian)(dian)路。

　　阻(zu)抗跟蹤(IT)技術(shu)非常獨特，比現有解決(jue)方案更為(wei)精確，原因是該技術(shu)具有的自學(xue)(xue)習(xi)機制能解決(jue)導致電(dian)池(chi)阻(zu)抗及空載(zai)條件下化學(xue)(xue)全容量(liang)(liang)(QMAX)發生變化的老化問(wen)題。阻(zu)抗跟蹤技術(shu)使(shi)用(yong)動態模(mo)擬(ni)算法學(xue)(xue)習(xi)并跟蹤電(dian)池(chi)特性，即(ji)在電(dian)池(chi)實際使(shi)用(yong)過程中(zhong)，先測量(liang)(liang)阻(zu)抗及容量(liang)(liang)值，然(ran)后跟蹤其變化。使(shi)用(yong)該算法則無(wu)需(xu)定期進行完(wan)整(zheng)周期容量(liang)(liang)校正。

　　利(li)用(yong)(yong)電(dian)(dian)池阻抗(kang)知(zhi)識，能夠實現精確(que)的(de)負載及溫(wen)度補償。最重要的(de)是，通過對電(dian)(dian)池參數的(de)動態學習，該測(ce)量(liang)法(fa)在電(dian)(dian)池的(de)整(zheng)個使(shi)(shi)用(yong)(yong)壽命內都能對電(dian)(dian)量(liang)進行精確(que)的(de)測(ce)量(liang)。與單(dan)獨使(shi)(shi)用(yong)(yong)庫侖(lun)計數法(fa)或電(dian)(dian)池電(dian)(dian)壓相關法(fa)相比，阻抗(kang)跟(gen)蹤技術在測(ce)量(liang)電(dian)(dian)池剩余容(rong)量(liang)方面(mian)更加出色。

　　顯示邏輯單元

　　顯(xian)示(shi)邏(luo)輯單(dan)(dan)(dan)元(yuan)是整個電(dian)路(lu)的核心單(dan)(dan)(dan)元(yuan)，該單(dan)(dan)(dan)元(yuan)需(xu)要(yao)將前級輸(shu)送的電(dian)池(chi)電(dian)量信(xin)息和其他檢測信(xin)號進行邏(luo)輯判斷，顯(xian)示(shi)邏(luo)輯單(dan)(dan)(dan)元(yuan)又包括以下幾(ji)個重(zhong)要(yao)組(zu)成部分：C1-振蕩(dang)器;C2-頻率選(xuan)擇單(dan)(dan)(dan)元(yuan);C3-電(dian)池(chi)短路(lu)檢測;C4-電(dian)源電(dian)池(chi)電(dian)壓(ya)比較單(dan)(dan)(dan)元(yuan);C5-電(dian)池(chi)充(chong)飽檢測。

　　其中，振(zhen)(zhen)蕩(dang)(dang)器(qi)單(dan)元為整個系統(tong)提供(gong)振(zhen)(zhen)蕩(dang)(dang)信號(hao)(hao)(hao)，由于(yu)LCD需要用開關(guan)信號(hao)(hao)(hao)控(kong)制(zhi)，所以振(zhen)(zhen)蕩(dang)(dang)器(qi)不僅為LCD提供(gong)基準的開關(guan)信號(hao)(hao)(hao)，還作為邏(luo)輯控(kong)制(zhi)信號(hao)(hao)(hao)控(kong)制(zhi)LCD的亮(liang)暗。頻率選(xuan)擇(ze)單(dan)元將振(zhen)(zhen)蕩(dang)(dang)器(qi)輸入的信號(hao)(hao)(hao)進行整合，實現電(dian)池電(dian)量(liang)分段(duan)顯(xian)示的功(gong)能(neng)：Vbat<3.7V,能(neng)量(liang)低于(yu)40%,LCD顯(xian)示屏四個格(ge)全(quan)滅;3.7V4.0V,能(neng)量(liang)約為100%,LCD顯(xian)示屏四個格(ge)全(quan)亮(liang)。

　　本方(fang)案采用(yong)變頻技術(shu)，在顯(xian)示充電(dian)進度時，每當(dang)一個bar停止閃(shan)爍(shuo)時，對還(huan)在閃(shan)爍(shuo)的其他bar調整頻率。當(dang)只剩下一個bar閃(shan)爍(shuo)時，閃(shan)爍(shuo)占空比為50%.

　　電(dian)(dian)(dian)(dian)(dian)(dian)源電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)(dian)壓比較單元通過比較電(dian)(dian)(dian)(dian)(dian)(dian)源與電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的(de)電(dian)(dian)(dian)(dian)(dian)(dian)壓，判斷充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)器是處在只(zhi)接電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的(de)狀(zhuang)態還是充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)狀(zhuang)態，當只(zhi)接電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的(de)狀(zhuang)態時(shi)，SE9120分(fen)段顯示(shi)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)(dian)量。在充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)狀(zhuang)態下，SE9120會控制LCD滾動顯示(shi)。具體分(fen)為以下幾(ji)種情況：Vbat<3.7V,能量低于40%,LCD四格(ge)滾動顯示(shi);

　　3.7V4.0V且C5電池充飽檢測單(dan)元檢測到電池已經充滿，能量約為(wei)100%,LCD顯示屏四(si)個格全亮。

　　LCD驅動單元

　　該單元不(bu)僅是(shi)給LCD屏一個驅動(dong)(dong)，此(ci)外(wai)，SE9120還解決了傳統(tong)方案(an)中，通過單邊驅動(dong)(dong)LCD的方法導致低電壓時LCD顯示亮度不(bu)足的問題。SE9120采用創新的雙邊驅動(dong)(dong)LCD方法使(shi)得電壓較低時仍能夠保(bao)持較高的LCD亮度。

　　LED背(bei)光(guang)驅動單元

　　該單元智能控制LED背光功能，當只(zhi)接電(dian)池時，可自動關閉LED藍(lan)色(se)背光，因而達到了省電(dian)的(de)功效(xiao)，同時也(ye)減少了電(dian)池的(de)消耗。

　　LED背(bei)光(guang)(guang)被用(yong)(yong)(yong)在(zai)小(xiao)巧(qiao)、廉價(jia)的(de)(de)(de)LCD面(mian)板(ban)(ban)上(shang)。他的(de)(de)(de)光(guang)(guang)通常是(shi)(shi)有顏色(se)的(de)(de)(de)，雖然(ran)白色(se)背(bei)光(guang)(guang)已經愈(yu)(yu)來愈(yu)(yu)普遍(bian)了。電(dian)光(guang)(guang)面(mian)板(ban)(ban)經常被使用(yong)(yong)(yong)在(zai)大型顯示上(shang)，這時(shi)均勻的(de)(de)(de)背(bei)光(guang)(guang)是(shi)(shi)很重要的(de)(de)(de)。電(dian)光(guang)(guang)面(mian)板(ban)(ban)需(xu)要經由高壓的(de)(de)(de)交流(liu)電(dian)來驅動，這部份由反用(yong)(yong)(yong)換流(liu)器(qi)回路(lu)來提供。冷陰極管被用(yong)(yong)(yong)在(zai)像是(shi)(shi)電(dian)腦(nao)顯示器(qi)上(shang)，顏色(se)上(shang)通常是(shi)(shi)白色(se)的(de)(de)(de)，這同樣也需(xu)要反用(yong)(yong)(yong)換流(liu)器(qi)和散光(guang)(guang)器(qi)。白熾背(bei)光(guang)(guang)則(ze)在(zai)需(xu)要高亮度(du)時(shi)被使用(yong)(yong)(yong)，但是(shi)(shi)其缺點則(ze)是(shi)(shi)白熾燈泡(pao)的(de)(de)(de)壽(shou)命相(xiang)當有限(xian)，而且(qie)會(hui)產(chan)生相(xiang)當多(duo)的(de)(de)(de)熱(re)量。