電(dian)(dian)電(dian)(dian)流(liu)(liu)大(da)于(yu)電(dian)(dian)池(chi)(chi)容(rong)量(liang)(liang)的(de)(de)20 隨著當今數(shu)碼電(dian)(dian)子(zi)產品(pin)功(gong)(gong)能的(de)(de)不斷增(zeng)加(jia)，LCD屏幕越來(lai)越大(da)，以(yi)及不斷增(zeng)強的(de)(de)多(duo)媒體視屏功(gong)(gong)能，市面上鋰離子(zi)/聚合(he)物(wu)電(dian)(dian)池(chi)(chi)的(de)(de)容(rong)量(liang)(liang)也做得(de)越來(lai)越大(da)。與此同時(shi)，消費者對(dui)縮(suo)短大(da)容(rong)量(liang)(liang)電(dian)(dian)池(chi)(chi)的(de)(de)充(chong)電(dian)(dian)時(shi)間提(ti)出了期望(wang)。為了能更快速有(you)效地對(dui)這些大(da)容(rong)量(liang)(liang)電(dian)(dian)池(chi)(chi)進行充(chong)電(dian)(dian)，以(yi)滿足消費者不斷增(zeng)長的(de)(de)需求(qiu)，無錫芯朋微電(dian)(dian)子(zi)推出了大(da)電(dian)(dian)流(liu)(liu)鋰離子(zi)電(dian)(dian)池(chi)(chi)充(chong)電(dian)(dian)芯片AP5056。

　　AP5056是可(ke)以對(dui)單節(jie)鋰(li)(li)離子或(huo)鋰(li)(li)聚合物可(ke)充(chong)電(dian)電(dian)池進行恒流/恒壓充(chong)電(dian)的(de)充(chong)電(dian)器(qi)(qi)電(dian)路。器(qi)(qi)件(jian)內部采用PMOSFET架構，應用時不(bu)需要外部另(ling)加阻流二極管。熱反饋電(dian)路可(ke)以自動調節(jie)充(chong)電(dian)電(dian)流，使器(qi)(qi)件(jian)在功耗(hao)比較(jiao)(jiao)大或(huo)者(zhe)環境溫(wen)度比較(jiao)(jiao)高(gao)的(de)情況(kuang)下將芯片溫(wen)度控制在安全范圍內。

　　AP5056只(zhi)需要極少的外圍元器件，可(ke)以適應(ying)USB 電(dian)(dian)源和(he)適配器電(dian)(dian)源工(gong)作，非(fei)常適用于便(bian)攜(xie)式應(ying)用的領域。充(chong)(chong)電(dian)(dian)輸出(chu)電(dian)(dian)壓為4.2V，充(chong)(chong)電(dian)(dian)電(dian)(dian)流的大小可(ke)以通(tong)過一個外部電(dian)(dian)阻設置。在恒(heng)壓充(chong)(chong)電(dian)(dian)階(jie)段中，當充(chong)(chong)電(dian)(dian)電(dian)(dian)流降至設定值1/10 時，AP5056將終止充(chong)(chong)電(dian)(dian)循環。

　　當輸入電(dian)(dian)(dian)(dian)壓(交流適配(pei)器或(huo)者USB電(dian)(dian)(dian)(dian)源)掉電(dian)(dian)(dian)(dian)時(shi)，AP5056自動進入低功耗的(de)睡眠模(mo)式(shi)，此時(shi)電(dian)(dian)(dian)(dian)池(chi)的(de)電(dian)(dian)(dian)(dian)流消耗小于2微安。其它功能(neng)(neng)包括(kuo)輸入電(dian)(dian)(dian)(dian)壓過低鎖存、芯片使(shi)能(neng)(neng)輸入、自動再充電(dian)(dian)(dian)(dian)、電(dian)(dian)(dian)(dian)池(chi)溫度監控以及(ji)狀(zhuang)態指(zhi)示等功能(neng)(neng)。

　　充(chong)電(dian)過程(cheng)：AP5056在整個(ge)電(dian)池充(chong)電(dian)過程(cheng)中有四種基本充(chong)電(dian)模式：涓流(liu)充(chong)電(dian)、恒流(liu)充(chong)電(dian)、恒壓充(chong)電(dian)和(he)充(chong)電(dian)完成(cheng)與(yu)再充(chong)電(dian)。

　　涓(juan)(juan)流(liu)(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)：充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)開始(shi)(shi)前，AP5056先檢(jian)查輸入電(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)，當(dang)輸入電(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)大(da)于最小(xiao)工作電(dian)(dian)(dian)(dian)(dian)壓(ya)或欠(qian)壓(ya)鎖定閾值(zhi)，并且芯(xin)片使(shi)能端接高電(dian)(dian)(dian)(dian)(dian)平時，AP5056開始(shi)(shi)對電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)。AP5056先檢(jian)查電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)的狀(zhuang)態。如果電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)(dian)壓(ya)高于3V，充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)器則(ze)進入恒流(liu)(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)；而如果電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)(dian)壓(ya)低于3V時，充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)器則(ze)進入涓(juan)(juan)流(liu)(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)模式。涓(juan)(juan)流(liu)(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)是(shi)(shi)恒流(liu)(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)的十分(fen)之(zhi)一(還是(shi)(shi)以恒定充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)為(wei)1A舉例，則(ze)涓(juan)(juan)流(liu)(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)為(wei)100mA)，涓(juan)(juan)流(liu)(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)狀(zhuang)態一直保(bao)持延續到(dao)(dao)AP5056芯(xin)片探測到(dao)(dao)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)(dian)壓(ya)達到(dao)(dao)3V后結束，之(zhi)后進入恒流(liu)(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)階段。

　　圖(tu)2：AP5056封裝。

　　恒流(liu)(liu)充電(dian)(dian)(dian)：恒流(liu)(liu)充電(dian)(dian)(dian)模式中，充電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)(liu)由(you)PROG腳與(yu)GND間的(de)電(dian)(dian)(dian)阻RPROG確定。(參見下(xia)文“可(ke)編(bian)程的(de)充電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)(liu)”)

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

　　AP5056進(jin)入恒流(liu)(liu)(liu)(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)模式中后，將一直按設定的電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)值(zhi)保持充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)，直到電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)慢(man)慢(man)到達電(dian)(dian)(dian)(dian)(dian)壓調節點4.2V，轉而進(jin)入恒壓充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)。恒壓充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)：在(zai)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)(dian)壓慢(man)慢(man)接近4.2V時，充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)器就漸(jian)漸(jian)轉為恒壓充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)。此(ci)時原先的恒流(liu)(liu)(liu)(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)也(ye)慢(man)慢(man)減(jian)小(xiao)，并隨著(zhu)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)容量(liang)越來越接近最大容量(liang)而急(ji)劇下降(jiang)。 充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)完成與(yu)再(zai)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)：當充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)被探測(ce)到減(jian)小(xiao)至恒流(liu)(liu)(liu)(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)的10%后，充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)器終止向電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)，進(jin)入低(di)功耗(hao)的待(dai)機模式。 在(zai)待(dai)機模式下，AP5056會繼續(xu)檢測(ce)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)端的電(dian)(dian)(dian)(dian)(dian)壓，如果電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)(dian)壓降(jiang)到4.05V以(yi)下，則充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)器將再(zai)次(ci)向電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)。

　　可編程(cheng)的充電電流：AP5056的充電電流由連(lian)接在PROG腳與GND之(zhi)間RPROG電阻來確定(ding)，計算公(gong)式如下：

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

　　例如，客戶需要得到一個1A的充電電流的話，根(gen)據公(gong)式(shi)得到

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

　　圖3顯(xian)示了(le)RPROG為1K和2K時(shi)，不同(tong)的電源輸入Vcc 與充(chong)(chong)電電流Ibat之(zhi)間的關(guan)系(xi)圖，可以看到充(chong)(chong)電輸出電流基本沒有(you)很(hen)大變化，只與RPROG的設定(ding)值有(you)關(guan)系(xi)。

　　圖3：電源(yuan)輸入Vcc VS 充電電流Ibat。

　　典型應用電路

　　圖4給出(chu)的(de)(de)是(shi)典型的(de)(de)應(ying)用電(dian)路，電(dian)路中R1, R2由NTC熱敏電(dian)阻(zu)值來確定。設熱敏電(dian)阻(zu)在最低(di)工作溫度(du)時(shi)的(de)(de)電(dian)阻(zu)為RTL，在最高工作溫度(du)時(shi)的(de)(de)電(dian)阻(zu)為RTH(RTL與RTH的(de)(de)數(shu)據(ju)可查電(dian)池廠方數(shu)據(ju)或做實驗得到)，則R1，R2的(de)(de)阻(zu)值分別為：

　　圖(tu)4：AP5056應用電路。

　　如果(guo)用戶只關(guan)心高溫保(bao)護，而不用關(guan)心低溫保(bao)護，則(ze)可(ke)將R2去掉，只保(bao)留R1，這時(shi)R1的計算公式變為：

　　直(zhi)流適配(pei)器與USB組合的方案

　當(dang)充電(dian)(dian)(dian)(dian)器(qi)需(xu)要直流(liu)適(shi)配器(qi)與(yu)USB充電(dian)(dian)(dian)(dian)兩者都能用(yong)時，可(ke)采(cai)用(yong)圖5所示(shi)的(de)方案。方案中，假如使用(yong)USB口進(jin)行(xing)供電(dian)(dian)(dian)(dian)的(de)話，MOS-P門極(ji)接地(di)，USB電(dian)(dian)(dian)(dian)源通(tong)過(guo)(guo)MOS-P導(dao)(dao)通(tong)至VCC，同(tong)時MOS-N處(chu)于(yu)(yu)關斷(duan)狀(zhuang)態(tai)，PROG上的(de)編程電(dian)(dian)(dian)(dian)阻為2K，即充電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)設定為500mA，這樣可(ke)防(fang)止USB接口被充電(dian)(dian)(dian)(dian)器(qi)拉(la)死；而(er)(er)當(dang)采(cai)用(yong)5V直流(liu)適(shi)配器(qi)的(de)時候，適(shi)配器(qi)電(dian)(dian)(dian)(dian)流(liu)通(tong)過(guo)(guo)肖(xiao)特基二(er)極(ji)管(guan)加至VCC腳，MOS-P由于(yu)(yu)門極(ji)為高電(dian)(dian)(dian)(dian)平而(er)(er)被截止，不會對USB口產生影響。同(tong)時MOS-N由于(yu)(yu)門極(ji)為高電(dian)(dian)(dian)(dian)平而(er)(er)導(dao)(dao)通(tong)，此時PROG腳上的(de)編程電(dian)(dian)(dian)(dian)阻相(xiang)當(dang)于(yu)(yu)1K(2個2K電(dian)(dian)(dian)(dian)阻并聯)，即設定充電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)為1A，來對鋰離(li)子電(dian)(dian)(dian)(dian)池(chi)進(jin)行(xing)快(kuai)速(su)充電(dian)(dian)(dian)(dian)。

　　圖5：交(jiao)流適配器與USB組合的方案。

　　芯片熱保護功能

　　利(li)用(yong)晶體管PN結的(de)(de)(de)(de)導通電(dian)(dian)壓隨溫度(du)(du)升(sheng)高(gao)而降低，而其(qi)變化值隨溫度(du)(du)的(de)(de)(de)(de)升(sheng)高(gao)而增加(jia)的(de)(de)(de)(de)特性，AP5056設計了(le)集(ji)成于芯片(pian)內(nei)部的(de)(de)(de)(de)過(guo)熱保護(hu)(hu)功(gong)(gong)能。當內(nei)部溫度(du)(du)傳(chuan)感器升(sheng)至約125℃以上時，內(nei)部的(de)(de)(de)(de)熱保護(hu)(hu)電(dian)(dian)路將自動減小充(chong)(chong)電(dian)(dian)電(dian)(dian)流的(de)(de)(de)(de)電(dian)(dian)流值，隨著(zhu)溫度(du)(du)的(de)(de)(de)(de)不斷升(sheng)高(gao)，當溫度(du)(du)達到145℃的(de)(de)(de)(de)時候，則可(ke)(ke)完(wan)全(quan)關閉充(chong)(chong)電(dian)(dian)電(dian)(dian)流。該功(gong)(gong)能可(ke)(ke)以讓用(yong)戶放心使用(yong)最大功(gong)(gong)率(lv)的(de)(de)(de)(de)充(chong)(chong)電(dian)(dian)電(dian)(dian)流而無需擔心芯片(pian)被損壞。

　　充電狀態指示

　　AP5056有CHRG和STDBY兩個狀態輸出(chu)指示。當充電器處于充電狀態時，CHRG置(zhi)低電平，STDBY輸出(chu)高(gao)阻(zu)態；當電池(chi)處于充滿狀態時，CHRG變(bian)為高(gao)阻(zu)態，STDBY被拉為低電平。

　　如果不需要用到狀(zhuang)(zhuang)態指示功能，可(ke)以(yi)將不用的(de)(de)相應的(de)(de)狀(zhuang)(zhuang)態輸出指示腳接地。

　　指示燈狀態

　　布板的注意事項

　　AP5056采用SOP8-PP封裝，芯片(pian)(pian)底部帶有(you)(you)散(san)(san)(san)(san)熱(re)(re)(re)片(pian)(pian)，以便于將芯片(pian)(pian)工作時產生(sheng)的熱(re)(re)(re)量通過散(san)(san)(san)(san)熱(re)(re)(re)片(pian)(pian)發散(san)(san)(san)(san)出去，因(yin)此，為了達到較好的散(san)(san)(san)(san)熱(re)(re)(re)效(xiao)果(guo)，散(san)(san)(san)(san)熱(re)(re)(re)片(pian)(pian)下的PC板銅(tong)(tong)箔(bo)(bo)面(mian)積(ji)要盡可能(neng)的寬(kuan)(kuan)闊(kuo)，并將之(zhi)延伸至外面(mian)更大，更寬(kuan)(kuan)的銅(tong)(tong)箔(bo)(bo)面(mian)積(ji)，而(er)且需將散(san)(san)(san)(san)熱(re)(re)(re)片(pian)(pian)與散(san)(san)(san)(san), 熱(re)(re)(re)片(pian)(pian)下的銅(tong)(tong)箔(bo)(bo)用焊(han)錫焊(han)接(jie)在一起，以增加(jia)熱(re)(re)(re)的傳導性；此外，利(li)用多個(ge)通孔將上層(ceng)銅(tong)(tong)箔(bo)(bo)與下層(ceng)銅(tong)(tong)箔(bo)(bo)連接(jie)起來能(neng)夠更有(you)(you)效(xiao)地拓展散(san)(san)(san)(san)熱(re)(re)(re)面(mian)積(ji)，有(you)(you)利(li)于將熱(re)(re)(re)量散(san)(san)(san)(san)至周圍環境(jing)中，增加(jia)充(chong)電芯片(pian)(pian)的散(san)(san)(san)(san)熱(re)(re)(re)效(xiao)果(guo)(如圖6所示)。

　　圖(tu)6：AP5056布板示(shi)意圖(tu)。

　　在芯片散熱良好的情況下(xia)，AP5056可提供電路最大充電電流(liu)為1600MA，實驗中，在室溫(wen)狀態(tai)下(xia)，充電電流(liu)設置(zhi)為1600MA，連(lian)續工(gong)作15分(fen)鐘，IC表面溫(wen)度為60℃；設置(zhi)為1000MA時，連(lian)續工(gong)作15分(fen)鐘，IC表面溫(wen)度為50℃。

％時：
充電(dian)時間（小時）＝電(dian)池容量（mAH）×1.1÷充電(dian)電(dian)流(mA)