電(dian)電(dian)流(liu)大(da)于電(dian)池容(rong)(rong)量(liang)的(de)20 隨著當(dang)今(jin)數碼電(dian)子(zi)產品功能(neng)的(de)不斷增(zeng)加，LCD屏(ping)幕越來越大(da)，以(yi)及不斷增(zeng)強的(de)多媒體視屏(ping)功能(neng)，市面上(shang)鋰離子(zi)/聚合(he)物電(dian)池的(de)容(rong)(rong)量(liang)也做得越來越大(da)。與此同時，消費者(zhe)對縮短大(da)容(rong)(rong)量(liang)電(dian)池的(de)充電(dian)時間提出了(le)期望。為了(le)能(neng)更快速有效地對這些大(da)容(rong)(rong)量(liang)電(dian)池進(jin)行充電(dian)，以(yi)滿(man)足消費者(zhe)不斷增(zeng)長的(de)需求，無錫(xi)芯(xin)朋微電(dian)子(zi)推出了(le)大(da)電(dian)流(liu)鋰離子(zi)電(dian)池充電(dian)芯(xin)片AP5056。

　　AP5056是可以(yi)(yi)對單節(jie)鋰離子或(huo)鋰聚合物(wu)可充(chong)電電池(chi)進(jin)行恒流(liu)/恒壓(ya)充(chong)電的充(chong)電器電路。器件內部(bu)采用PMOSFET架構(gou)，應用時(shi)不需要外(wai)部(bu)另(ling)加阻流(liu)二(er)極管。熱反饋電路可以(yi)(yi)自動調節(jie)充(chong)電電流(liu)，使器件在功(gong)耗(hao)比(bi)較大或(huo)者環境溫(wen)度(du)比(bi)較高的情況下將芯(xin)片溫(wen)度(du)控制(zhi)在安全(quan)范(fan)圍內。

　　AP5056只需要(yao)極少的(de)外圍元器件，可以(yi)適應(ying)(ying)USB 電(dian)(dian)源和適配器電(dian)(dian)源工作，非(fei)常適用于(yu)便攜式應(ying)(ying)用的(de)領域(yu)。充(chong)(chong)電(dian)(dian)輸(shu)出(chu)電(dian)(dian)壓為(wei)4.2V，充(chong)(chong)電(dian)(dian)電(dian)(dian)流(liu)的(de)大小可以(yi)通(tong)過(guo)一(yi)個外部電(dian)(dian)阻(zu)設(she)置。在恒壓充(chong)(chong)電(dian)(dian)階(jie)段中，當充(chong)(chong)電(dian)(dian)電(dian)(dian)流(liu)降至設(she)定值1/10 時，AP5056將終止充(chong)(chong)電(dian)(dian)循(xun)環。

　　當輸(shu)(shu)入電壓(ya)(交流適配(pei)器或者USB電源)掉電時，AP5056自(zi)動進入低功耗的睡眠模式，此時電池(chi)的電流消耗小于2微安(an)。其(qi)它(ta)功能(neng)包括(kuo)輸(shu)(shu)入電壓(ya)過(guo)低鎖存(cun)、芯(xin)片(pian)使能(neng)輸(shu)(shu)入、自(zi)動再(zai)充(chong)電、電池(chi)溫度(du)監控以(yi)及狀態指示等功能(neng)。

　　充電(dian)過程：AP5056在整個電(dian)池充電(dian)過程中有四種(zhong)基本充電(dian)模式：涓流充電(dian)、恒(heng)流充電(dian)、恒(heng)壓充電(dian)和充電(dian)完成與再充電(dian)。

　　涓(juan)流(liu)(liu)(liu)(liu)(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)：充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)開始(shi)前(qian)，AP5056先(xian)(xian)檢查輸(shu)入(ru)(ru)電(dian)(dian)(dian)(dian)(dian)源，當輸(shu)入(ru)(ru)電(dian)(dian)(dian)(dian)(dian)源大于(yu)最小工作電(dian)(dian)(dian)(dian)(dian)壓或欠(qian)壓鎖定閾值，并且芯(xin)(xin)片(pian)使能(neng)端接高電(dian)(dian)(dian)(dian)(dian)平時(shi)，AP5056開始(shi)對電(dian)(dian)(dian)(dian)(dian)池充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)。AP5056先(xian)(xian)檢查電(dian)(dian)(dian)(dian)(dian)池的狀(zhuang)態。如果電(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)壓高于(yu)3V，充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)器則(ze)進(jin)入(ru)(ru)恒(heng)流(liu)(liu)(liu)(liu)(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)；而如果電(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)壓低于(yu)3V時(shi)，充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)器則(ze)進(jin)入(ru)(ru)涓(juan)流(liu)(liu)(liu)(liu)(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)模式。涓(juan)流(liu)(liu)(liu)(liu)(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)是(shi)恒(heng)流(liu)(liu)(liu)(liu)(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)的十分之(zhi)一(還是(shi)以恒(heng)定充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)為1A舉例，則(ze)涓(juan)流(liu)(liu)(liu)(liu)(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)為100mA)，涓(juan)流(liu)(liu)(liu)(liu)(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)狀(zhuang)態一直保持延續到AP5056芯(xin)(xin)片(pian)探測(ce)到電(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)壓達到3V后結束，之(zhi)后進(jin)入(ru)(ru)恒(heng)流(liu)(liu)(liu)(liu)(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)階段。

　　圖2：AP5056封裝。

　　恒流(liu)(liu)充(chong)電：恒流(liu)(liu)充(chong)電模式中，充(chong)電電流(liu)(liu)由PROG腳(jiao)與GND間的電阻RPROG確(que)定。(參見下(xia)文“可(ke)編程的充(chong)電電流(liu)(liu)”)

　　IBAT = (VPROG/ RPROG)?1000 (VPROG的典型值為1V)

　　AP5056進(jin)入(ru)恒(heng)流(liu)(liu)充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)模式(shi)中(zhong)后，將一(yi)直按設(she)定(ding)的(de)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)值(zhi)保持充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)，直到電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)慢(man)(man)慢(man)(man)到達電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)調節點4.2V，轉而進(jin)入(ru)恒(heng)壓(ya)(ya)充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)。恒(heng)壓(ya)(ya)充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)：在電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)慢(man)(man)慢(man)(man)接(jie)(jie)近(jin)4.2V時，充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)器(qi)就漸(jian)漸(jian)轉為(wei)恒(heng)壓(ya)(ya)充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)。此時原先的(de)恒(heng)流(liu)(liu)充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)也(ye)慢(man)(man)慢(man)(man)減小(xiao)，并隨著電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)容(rong)量越來越接(jie)(jie)近(jin)最大容(rong)量而急劇下降。 充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)完成與再(zai)充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)：當充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)被探(tan)測到減小(xiao)至恒(heng)流(liu)(liu)充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)的(de)10%后，充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)器(qi)終止向(xiang)(xiang)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)，進(jin)入(ru)低功(gong)耗的(de)待(dai)機模式(shi)。 在待(dai)機模式(shi)下，AP5056會(hui)繼續(xu)檢測電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)端(duan)的(de)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)，如果電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)降到4.05V以下，則(ze)充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)器(qi)將再(zai)次(ci)向(xiang)(xiang)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)。

　　可(ke)編程的充(chong)電電流(liu)：AP5056的充(chong)電電流(liu)由連接(jie)在PROG腳與GND之間RPROG電阻來確定，計算公式如下：

　　IBAT = (VPROG/ RPROG)?1000 (VPROG的(de)典型值(zhi)為1V)

　　例如(ru)，客戶需要(yao)得到(dao)一個1A的充電(dian)電(dian)流的話，根(gen)據(ju)公式得到(dao)

　　1A = (1/ RPROG)?1000，解方程式得(de)VPROG = 1000Ω，即VPROG = 1KΩ

　　圖(tu)3顯示(shi)了RPROG為1K和2K時，不同的電(dian)源輸入Vcc 與充電(dian)電(dian)流Ibat之(zhi)間(jian)的關(guan)系圖(tu)，可(ke)以看到充電(dian)輸出電(dian)流基(ji)本沒(mei)有很大變化，只與RPROG的設定值有關(guan)系。

　　圖3：電(dian)源輸(shu)入Vcc VS 充電(dian)電(dian)流Ibat。

　　典型應用電路

　　圖4給出(chu)的(de)是典型(xing)的(de)應用(yong)電(dian)路(lu)，電(dian)路(lu)中R1, R2由(you)NTC熱敏電(dian)阻值(zhi)來(lai)確(que)定。設(she)熱敏電(dian)阻在(zai)最低工作溫度(du)時(shi)的(de)電(dian)阻為RTL，在(zai)最高工作溫度(du)時(shi)的(de)電(dian)阻為RTH(RTL與RTH的(de)數據可查(cha)電(dian)池廠方數據或做實驗得到)，則R1，R2的(de)阻值(zhi)分(fen)別為：

　　圖4：AP5056應用電路。

　　如果用戶只(zhi)關(guan)心高溫保護(hu)，而不用關(guan)心低溫保護(hu)，則可(ke)將R2去掉，只(zhi)保留R1，這時R1的計算(suan)公式變為：

　　直流(liu)適配器(qi)與USB組合的方案

　當充電(dian)器需要直流(liu)適配(pei)器與USB充電(dian)兩(liang)者(zhe)都能用時(shi)，可采(cai)用圖5所示的(de)方(fang)案(an)。方(fang)案(an)中，假如(ru)使(shi)用USB口(kou)進行供電(dian)的(de)話，MOS-P門(men)極(ji)接地，USB電(dian)源(yuan)通(tong)(tong)過(guo)MOS-P導通(tong)(tong)至VCC，同時(shi)MOS-N處于關斷狀態，PROG上(shang)的(de)編(bian)程(cheng)電(dian)阻為(wei)(wei)2K，即(ji)(ji)充電(dian)電(dian)流(liu)設定(ding)為(wei)(wei)500mA，這(zhe)樣可防止USB接口(kou)被充電(dian)器拉死(si)；而當采(cai)用5V直流(liu)適配(pei)器的(de)時(shi)候(hou)，適配(pei)器電(dian)流(liu)通(tong)(tong)過(guo)肖特(te)基二極(ji)管加至VCC腳，MOS-P由于門(men)極(ji)為(wei)(wei)高電(dian)平而被截止，不會對USB口(kou)產生影響。同時(shi)MOS-N由于門(men)極(ji)為(wei)(wei)高電(dian)平而導通(tong)(tong)，此時(shi)PROG腳上(shang)的(de)編(bian)程(cheng)電(dian)阻相當于1K(2個2K電(dian)阻并(bing)聯)，即(ji)(ji)設定(ding)充電(dian)電(dian)流(liu)為(wei)(wei)1A，來對鋰離子(zi)電(dian)池進行快速(su)充電(dian)。

　　圖5：交流適配器與(yu)USB組(zu)合的方案。

　　芯片熱保護功能

　　利用晶體管PN結的(de)(de)導通電(dian)(dian)壓隨溫度升高而(er)降低，而(er)其變(bian)化值隨溫度的(de)(de)升高而(er)增(zeng)加的(de)(de)特性，AP5056設計了集成于芯片內部(bu)的(de)(de)過(guo)熱(re)保護功能。當內部(bu)溫度傳感器升至約125℃以上時，內部(bu)的(de)(de)熱(re)保護電(dian)(dian)路將自動減小充(chong)電(dian)(dian)電(dian)(dian)流的(de)(de)電(dian)(dian)流值，隨著溫度的(de)(de)不斷升高，當溫度達(da)到145℃的(de)(de)時候，則可完全關(guan)閉充(chong)電(dian)(dian)電(dian)(dian)流。該功能可以讓用戶放心(xin)使用最大(da)功率的(de)(de)充(chong)電(dian)(dian)電(dian)(dian)流而(er)無需擔心(xin)芯片被損壞。

　　充電狀態指示

　　AP5056有CHRG和STDBY兩(liang)個狀態(tai)輸出(chu)指示。當充(chong)(chong)電(dian)器處于充(chong)(chong)電(dian)狀態(tai)時，CHRG置低電(dian)平，STDBY輸出(chu)高阻態(tai)；當電(dian)池處于充(chong)(chong)滿狀態(tai)時，CHRG變為高阻態(tai)，STDBY被拉為低電(dian)平。

　　如果不需(xu)要用到狀態指(zhi)示功能，可以將不用的相應的狀態輸出指(zhi)示腳接地。

　　指示燈狀態

　　布板的注意事項

　　AP5056采用(yong)SOP8-PP封(feng)裝，芯(xin)片底部(bu)帶有散(san)(san)熱(re)(re)片，以便(bian)于(yu)將芯(xin)片工(gong)作(zuo)時(shi)產生的熱(re)(re)量(liang)通(tong)(tong)過(guo)散(san)(san)熱(re)(re)片發散(san)(san)出(chu)去(qu)，因此，為了達到較(jiao)好(hao)的散(san)(san)熱(re)(re)效(xiao)果，散(san)(san)熱(re)(re)片下(xia)的PC板銅箔面積(ji)要盡可能的寬闊，并將之延伸至(zhi)外面更(geng)(geng)大，更(geng)(geng)寬的銅箔面積(ji)，而且需將散(san)(san)熱(re)(re)片與散(san)(san), 熱(re)(re)片下(xia)的銅箔用(yong)焊錫焊接(jie)在一起，以增加熱(re)(re)的傳導性(xing)；此外，利用(yong)多個通(tong)(tong)孔將上層銅箔與下(xia)層銅箔連(lian)接(jie)起來能夠更(geng)(geng)有效(xiao)地拓展散(san)(san)熱(re)(re)面積(ji)，有利于(yu)將熱(re)(re)量(liang)散(san)(san)至(zhi)周圍(wei)環境中，增加充電芯(xin)片的散(san)(san)熱(re)(re)效(xiao)果(如圖(tu)6所示)。

　　圖6：AP5056布板示意圖。

　　在芯片散(san)熱良(liang)好(hao)的情況下(xia)，AP5056可提(ti)供電路最大充(chong)電電流(liu)為1600MA，實驗中，在室溫(wen)狀(zhuang)態下(xia)，充(chong)電電流(liu)設(she)置為1600MA，連(lian)續工(gong)作(zuo)15分(fen)鐘，IC表(biao)(biao)面溫(wen)度為60℃；設(she)置為1000MA時，連(lian)續工(gong)作(zuo)15分(fen)鐘，IC表(biao)(biao)面溫(wen)度為50℃。

％時：
充(chong)電(dian)時間(jian)（小時）＝電(dian)池容量(liang)（mAH）×1.1÷充(chong)電(dian)電(dian)流(mA)