1、近(jin)十年來，隨(sui)著(zhu)各種便攜式設(she)備（如手(shou)機(ji)(ji)、筆記本(ben)(ben)電(dian)腦 、攝像機(ji)(ji) 、數碼相機(ji)(ji) 、PDA 等）的(de)(de)(de)(de)不(bu)斷推(tui)出 ，對(dui)電(dian)池(chi)(chi)(chi)的(de)(de)(de)(de)要求(qiu)也隨(sui)之提(ti)高(gao)。以(yi)前，在這(zhe)類應(ying)用中 ，NiMH電(dian)池(chi)(chi)(chi)和(he)(he)NiCD電(dian)池(chi)(chi)(chi)，以(yi)其低(di)價格占(zhan)有較大(da)優勢；但隨(sui)著(zhu)便攜式設(she)備對(dui)體積/重量的(de)(de)(de)(de)要求(qiu)越來越苛刻(ke)，工(gong)作和(he)(he)待機(ji)(ji)時間越來越長以(yi)及Li電(dian)池(chi)(chi)(chi)成本(ben)(ben)的(de)(de)(de)(de)不(bu)斷降(jiang)低(di)，使 Li電(dian)池(chi)(chi)(chi)的(de)(de)(de)(de)優勢性能在這(zhe)類應(ying)用中得以(yi)充(chong)分的(de)(de)(de)(de)展示，被廣大(da)電(dian)子設(she)計工(gong)程師和(he)(he)消費者所接受(shou)。隨(sui)著(zhu)Li電(dian)池(chi)(chi)(chi)性能的(de)(de)(de)(de)不(bu)斷提(ti)高(gao)和(he)(he)成本(ben)(ben)的(de)(de)(de)(de)進一步降(jiang)低(di) ，Li電(dian)池(chi)(chi)(chi)將在許多應(ying)用中取代(dai)NiCD和(he)(he)NiMH電(dian)池(chi)(chi)(chi) 。

　　雖然鋰(li)離子電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)有以上(shang)種種優點和良好的(de)市(shi)場前(qian)景，但它對充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)路的(de)要(yao)求比較高，在使(shi)用過(guo)程(cheng)中要(yao)避免出現過(guo)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)和過(guo)放電(dian)(dian)(dian)(dian)(dian)(dian)的(de)現象。鋰(li)離子電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)過(guo)程(cheng)如圖１所示，在一個充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)周(zhou)期(qi)內(nei)，鋰(li)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)在充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)開始之前(qian)需(xu)要(yao)檢測電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)的(de)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)和溫度(du)，判斷是否可充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)，如果電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)或溫度(du)超出允許范圍，則禁(jin)止充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)。每節(jie)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)的(de)允許充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)為(wei)(wei)2.5-4.2V，溫度(du)為(wei)(wei)2.5-50℃。在電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)處于深放電(dian)(dian)(dian)(dian)(dian)(dian)的(de)情況下(xia)，必須(xu)要(yao)求充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)器具有預充(chong)(chong)(chong)過(guo)程(cheng)，使(shi)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)滿(man)(man)(man)足快(kuai)速(su)(su)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)的(de)條件，然后根據電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)廠商推(tui)薦的(de)快(kuai)速(su)(su)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)速(su)(su)度(du)對電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)進行恒(heng)流(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)，電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)緩(huan)慢(man)上(shang)升；一旦電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)達到所設定的(de)終止電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)（一般為(wei)(wei) 4.1V 或4.2V），恒(heng)流(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)終止，充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)快(kuai)速(su)(su)衰減，充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)進入(ru)滿(man)(man)(man)充(chong)(chong)(chong)過(guo)程(cheng)；在滿(man)(man)(man)充(chong)(chong)(chong)過(guo)程(cheng)中，充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)逐漸衰減，直到滿(man)(man)(man)充(chong)(chong)(chong)時(shi)間超時(shi)，轉入(ru)頂端(duan)截止充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)；頂端(duan)截止充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)時(shi)，充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)器以極小(xiao)的(de)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)為(wei)(wei)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)補充(chong)(chong)(chong)能(neng)量；頂端(duan)截止充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)一段時(shi)間后，關閉充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)。

2　MAX1501簡介
　　
　　MAXIM公司的MAX1501是一種全新的溫度調節線性充電器采用16引腳TQFN封裝(zhuang)，可為鋰離(li)子(zi)、鎳(nie)鎘(ge)、鎳(nie)氫(qing)電池(chi)進行充電.MAX1501的特點及(ji)其引腳功(gong)能。它具有(you)如下特點：

　　1.獨立運行或由微(wei)處理器控制(zhi)的(de)線性充電方案；

　　2.輸入大于6.5v時充電停止；

　　3.電流檢測(ce)監視器輸出；

　　4.電(dian)池電(dian)壓(ya)下降4v以下后自動(dong)啟(qi)動(dong)充電(dian)；

　　5.無電池(chi)時仍然(ran)保持(chi)穩定輸出；

　　6.集(ji)成(cheng)了PMOSFET.反向阻斷(duan)二極管和檢測電流電阻；

　　7.薄型(xing)QFN封裝(zhuang)的多化學類型(xing)充(chong)電器。

3　MAX1501引(yin)腳功能

　　INP：高電流充電輸入；

　　IN: 低電(dian)流充電(dian)輸入(ru)；

　　GND： 地.連接外部開關到(dao)地；

　　SETI：電流傳感跨導放大(da)輸出；

　　VL： 線(xian)性輸出調(diao)整器(qi)；

　　TMAX： 輸入最大充(chong)電時間(jian)選擇(僅對max1501)；

　　IC：　 MAX1501Z的內(nei)部(bu)連接.隨浮動；

　　FULLI： 最大(da)關(guan)閉電(dian)流(liu)選擇(ze)輸入；

　　TEMP：衰耗溫度選擇輸入；
　　

4　鋰離子電池充電器的研制

　　MAX1501的(de)最典型的(de)應用是能夠用10%的(de)快(kuai)速充電(dian)(dian)電(dian)(dian)流(liu)(liu)對(dui)鋰離子電(dian)(dian)池(chi)進(jin)(jin)行預充電(dian)(dian)，用一(yi)個(ge)軟啟(qi)動系統持續增(zeng)加(jia)充電(dian)(dian)電(dian)(dian)流(liu)(liu)。以每20ms增(zeng)加(jia)10%直到(dao)電(dian)(dian)壓(ya)達到(dao)2.8V，當電(dian)(dian)池(chi)電(dian)(dian)壓(ya)達到(dao)規格電(dian)(dian)壓(ya)4.1V/4.2V時(shi)進(jin)(jin)入常壓(ya)狀(zhuang)態并且減少(shao)充電(dian)(dian)電(dian)(dian)流(liu)(liu)。在SETI與地之間設(she)置(zhi)一(yi)個(ge)晶體管(guan)來(lai)控制快(kuai)速充電(dian)(dian)電(dian)(dian)流(liu)(liu)，并且通過(guo)減少(shao)輸入電(dian)(dian)流(liu)(liu)使MAX1501遠離過(guo)熱(re)，溫(wen)度調節(jie)電(dian)(dian)路(lu)調節(jie)MAX1501的(de)溫(wen)度。當到(dao)達頂端(duan)關斷電(dian)(dian)流(liu)(liu)的(de)關斷值時(shi)RLED腳(jiao)作用一(yi)個(ge)高阻抗

進入低維護狀態。 當電(dian)池電(dian)壓低與95%時(shi)，通過設置SELV可(ke)以自(zi)動進行在(zai)充電(dian)。

　　（1）設置充電電流(liu)

　　設定電(dian)阻充(chong)電(dian)電(dian)流根據下列公式

　　（2）設置電容

　　為了獲得合適(shi)的(de)穩定性，可(ke)以(yi)用(yong)一個陶(tao)瓷電容(rong)(rong)最常用(yong)10uF 5R陶(tao)瓷電容(rong)(rong)來(lai)連接BATT到GND。將(jiang)IN和INP連接起來(lai)并且到GND用(yong)1uF的(de)陶(tao)瓷電容(rong)(rong)。由(you)于過高輸入電壓或(huo)過高充(chong)電電流，可(ke)用(yong)更(geng)大(da)的(de)輸入途(tu)徑電容(rong)(rong)來(lai)降低噪聲。

　　（3）設置溫(wen)度調節

　　在(zai)邏輯(ji)輸入(ru)條(tiao)件下設置規則的(de)(de)死(si)機溫(wen)度，MAX1501通過(guo)降低充電電流來限制由TEMP設定(ding)的(de)(de)死(si)機溫(wen)度值。MAX1501運行正常，溫(wen)度環路不會顯示(shi)異常情況。TEMP允(yun)許在(zai)提供過(guo)多的(de)(de)能量損失的(de)(de)保護的(de)(de)前(qian)提下將充電電流擴展到最大限度。

　　（4）設(she)置充電(dian)時間

　　在TMAX邏輯輸入(ru)條件下設(she)置最(zui)大充(chong)電(dian)(dian)時(shi)(shi)間(jian)。TMAX限制充(chong)電(dian)(dian)周期用來(lai)(lai)保護電(dian)(dian)池充(chong)電(dian)(dian)過(guo)長(chang)。將TMAX與GND連接起(qi)來(lai)(lai)可(ke)將最(zui)長(chang)充(chong)電(dian)(dian)時(shi)(shi)間(jian)設(she)置為三小(xiao)時(shi)(shi)。將TMAX懸空(kong)可(ke)將最(zui)大充(chong)電(dian)(dian)時(shi)(shi)間(jian)設(she)置為4.5小(xiao)時(shi)(shi)。將TMAX和VL連接起(qi)來(lai)(lai)可(ke)將最(zui)長(chang)充(chong)電(dian)(dian)時(shi)(shi)間(jian)設(she)置為6小(xiao)時(shi)(shi)。

　　（5）綜述討論

　　MAX1501和一(yi)個(ge)(ge)微處理(li)器相結合從而決(jue)定它有(you)很好的充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)方案專用的熱(re)調(diao)節(jie)電(dian)(dian)(dian)(dian)(dian)路用來(lai)限制(zhi)電(dian)(dian)(dian)(dian)(dian)路節(jie)點溫度，當(dang)快(kuai)速充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)或當(dang)環境溫度很高的時(shi)候確保最大(da)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)不(bu)會損壞充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)器，在(zai)沒有(you)電(dian)(dian)(dian)(dian)(dian)池(chi)的情況下MAX1501提供(gong)可調(diao)節(jie)的輸出電(dian)(dian)(dian)(dian)(dian)壓(ya)，在(zai)允許電(dian)(dian)(dian)(dian)(dian)池(chi)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)的情況下這個(ge)(ge)裝置有(you)較高的適應性, 安(an)全時(shi)間(jian)內可以提供(gong)一(yi)個(ge)(ge)可調(diao)整的快(kuai)速充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu),頂(ding)端關斷(duan)電(dian)(dian)(dian)(dian)(dian)流(liu),.并且(qie)有(you)熱(re)量方嵌條調(diao)整點.其(qi)它特點包括輸入電(dian)(dian)(dian)(dian)(dian)量檢測(ce)

并且有輸入低(di)的過壓(ya)(ya)保護和(he)規定了較低(di)的控(kong)制(zhi)輸入.MAX1501能(neng)夠接受一(yi)個4.5V到13V的電(dian)(dian)壓(ya)(ya)供電(dian)(dian).但是當輸入電(dian)(dian)壓(ya)(ya)超(chao)過6.5伏時為了防止(zhi)過多(duo)的能(neng)量消耗MAX1501充電(dian)(dian)停止(zhi).MAX1501擴大(da)了溫度范圍(-40°C to +85°C)并且體(ti)積也(ye)減小了.

5　結束語

　　本文介紹了一種采用ＭＡＸ1501 充電控制芯片設計的簡單實用的鋰離子電池充電器，最后(hou)對電路的特性及充電參數的設(she)置進行了分析。