電(dian)電(dian)流大(da)于電(dian)池(chi)容(rong)(rong)量(liang)(liang)的(de)20 隨著當今數碼電(dian)子(zi)產品(pin)功(gong)能的(de)不(bu)斷增(zeng)(zeng)加，LCD屏(ping)幕越來越大(da)，以及不(bu)斷增(zeng)(zeng)強的(de)多媒體視屏(ping)功(gong)能，市面(mian)上鋰(li)(li)離(li)子(zi)/聚合物(wu)電(dian)池(chi)的(de)容(rong)(rong)量(liang)(liang)也做得(de)越來越大(da)。與此同時，消(xiao)費者對(dui)縮(suo)短大(da)容(rong)(rong)量(liang)(liang)電(dian)池(chi)的(de)充(chong)電(dian)時間提(ti)出了期望。為(wei)了能更快速有效地對(dui)這些大(da)容(rong)(rong)量(liang)(liang)電(dian)池(chi)進行充(chong)電(dian)，以滿(man)足(zu)消(xiao)費者不(bu)斷增(zeng)(zeng)長(chang)的(de)需求，無錫(xi)芯(xin)朋微電(dian)子(zi)推出了大(da)電(dian)流鋰(li)(li)離(li)子(zi)電(dian)池(chi)充(chong)電(dian)芯(xin)片AP5056。

　　AP5056是可以(yi)對(dui)單節(jie)鋰(li)離子或鋰(li)聚合(he)物(wu)可充(chong)(chong)電(dian)(dian)電(dian)(dian)池進行恒流/恒壓充(chong)(chong)電(dian)(dian)的充(chong)(chong)電(dian)(dian)器(qi)(qi)電(dian)(dian)路(lu)。器(qi)(qi)件內部(bu)采用PMOSFET架構，應用時不需要外部(bu)另加阻流二極管。熱反饋電(dian)(dian)路(lu)可以(yi)自動調節(jie)充(chong)(chong)電(dian)(dian)電(dian)(dian)流，使器(qi)(qi)件在(zai)(zai)功耗比較(jiao)大或者(zhe)環境溫度比較(jiao)高的情況下將(jiang)芯(xin)片溫度控(kong)制在(zai)(zai)安全范圍內。

　　AP5056只需要極少的(de)外(wai)圍元器(qi)件(jian)，可(ke)以適(shi)應USB 電(dian)(dian)源(yuan)和(he)適(shi)配器(qi)電(dian)(dian)源(yuan)工作，非常適(shi)用于便攜式應用的(de)領(ling)域。充(chong)(chong)(chong)電(dian)(dian)輸出電(dian)(dian)壓(ya)為4.2V，充(chong)(chong)(chong)電(dian)(dian)電(dian)(dian)流的(de)大小可(ke)以通過(guo)一個(ge)外(wai)部電(dian)(dian)阻(zu)設置。在恒壓(ya)充(chong)(chong)(chong)電(dian)(dian)階(jie)段中(zhong)，當(dang)充(chong)(chong)(chong)電(dian)(dian)電(dian)(dian)流降至設定值1/10 時，AP5056將終止(zhi)充(chong)(chong)(chong)電(dian)(dian)循(xun)環(huan)。

　　當輸(shu)(shu)入(ru)電(dian)(dian)壓(交流適(shi)配器或者USB電(dian)(dian)源(yuan))掉電(dian)(dian)時，AP5056自(zi)動(dong)進(jin)入(ru)低功(gong)耗的睡(shui)眠模(mo)式(shi)，此時電(dian)(dian)池(chi)的電(dian)(dian)流消耗小于2微安。其它功(gong)能包括輸(shu)(shu)入(ru)電(dian)(dian)壓過低鎖存、芯片使能輸(shu)(shu)入(ru)、自(zi)動(dong)再充(chong)電(dian)(dian)、電(dian)(dian)池(chi)溫度監控以及狀態指示(shi)等功(gong)能。

　　充(chong)(chong)電過程：AP5056在整個(ge)電池充(chong)(chong)電過程中有(you)四(si)種基(ji)本充(chong)(chong)電模式：涓流(liu)充(chong)(chong)電、恒流(liu)充(chong)(chong)電、恒壓充(chong)(chong)電和充(chong)(chong)電完成(cheng)與再充(chong)(chong)電。

　　涓(juan)(juan)流(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(xian)檢查輸(shu)入電(dian)(dian)(dian)(dian)(dian)源(yuan)，當輸(shu)入電(dian)(dian)(dian)(dian)(dian)源(yuan)大(da)于最小工作電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)或欠壓(ya)(ya)鎖定(ding)(ding)閾值，并且芯(xin)片使能(neng)端接高電(dian)(dian)(dian)(dian)(dian)平時(shi)(shi)，AP5056開始(shi)(shi)對電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)。AP5056先(xian)檢查電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)的狀態。如果(guo)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)高于3V，充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)器則進入恒(heng)流(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)；而(er)如果(guo)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)低于3V時(shi)(shi)，充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)器則進入涓(juan)(juan)流(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)模式(shi)。涓(juan)(juan)流(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)是恒(heng)流(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)的十分之一(還(huan)是以恒(heng)定(ding)(ding)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)為(wei)1A舉例(li)，則涓(juan)(juan)流(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)為(wei)100mA)，涓(juan)(juan)流(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)狀態一直保持延(yan)續到(dao)AP5056芯(xin)片探測到(dao)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)達到(dao)3V后結束，之后進入恒(heng)流(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)階(jie)段。

　　圖2：AP5056封裝(zhuang)。

　　恒(heng)流(liu)充電(dian)(dian)：恒(heng)流(liu)充電(dian)(dian)模式中，充電(dian)(dian)電(dian)(dian)流(liu)由(you)PROG腳與GND間的電(dian)(dian)阻(zu)RPROG確定。(參(can)見下(xia)文“可編(bian)程(cheng)的充電(dian)(dian)電(dian)(dian)流(liu)”)

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

　　AP5056進(jin)入(ru)恒流(liu)(liu)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)模式中(zhong)后，將一直按設定的(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)值(zhi)保(bao)持充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，直到電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)慢(man)(man)慢(man)(man)到達電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓調節點4.2V，轉而進(jin)入(ru)恒壓充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)。恒壓充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)：在電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓慢(man)(man)慢(man)(man)接(jie)近4.2V時，充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)器(qi)就漸漸轉為恒壓充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)。此時原(yuan)先(xian)的(de)恒流(liu)(liu)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)也慢(man)(man)慢(man)(man)減(jian)小(xiao)，并隨著電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)容(rong)量越來越接(jie)近最大容(rong)量而急劇下降。 充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)完成與再充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)：當充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)被(bei)探測(ce)到減(jian)小(xiao)至恒流(liu)(liu)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)的(de)10%后，充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)器(qi)終(zhong)止向(xiang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，進(jin)入(ru)低(di)功耗(hao)的(de)待機(ji)模式。 在待機(ji)模式下，AP5056會繼續檢(jian)測(ce)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)端(duan)的(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓，如果(guo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓降到4.05V以下，則充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)器(qi)將再次(ci)向(xiang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)。

　　可編程(cheng)的(de)(de)充(chong)電電流：AP5056的(de)(de)充(chong)電電流由連接(jie)在(zai)PROG腳與GND之(zhi)間RPROG電阻來確(que)定，計(ji)算公(gong)式如下：

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

　　例如，客戶需要得(de)到一個1A的充電(dian)電(dian)流的話，根(gen)據公式得(de)到

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

　　圖(tu)3顯示了RPROG為1K和2K時(shi)，不(bu)同的(de)電(dian)源輸(shu)入Vcc 與充電(dian)電(dian)流(liu)Ibat之間的(de)關(guan)系圖(tu)，可以(yi)看到充電(dian)輸(shu)出電(dian)流(liu)基本(ben)沒(mei)有(you)(you)很(hen)大變化(hua)，只與RPROG的(de)設定值有(you)(you)關(guan)系。

　　圖3：電源輸入Vcc VS 充電電流Ibat。

　　典型應用電路

　　圖4給(gei)出的(de)是典(dian)型的(de)應用電(dian)(dian)路，電(dian)(dian)路中(zhong)R1, R2由(you)NTC熱敏(min)電(dian)(dian)阻值(zhi)來確定(ding)。設熱敏(min)電(dian)(dian)阻在(zai)最(zui)低工作(zuo)溫度時的(de)電(dian)(dian)阻為(wei)RTL，在(zai)最(zui)高工作(zuo)溫度時的(de)電(dian)(dian)阻為(wei)RTH(RTL與RTH的(de)數據(ju)可查(cha)電(dian)(dian)池(chi)廠方數據(ju)或做(zuo)實(shi)驗得到)，則(ze)R1，R2的(de)阻值(zhi)分別為(wei)：

　　圖4：AP5056應用電路(lu)。

　　如果用戶(hu)只關心高溫保(bao)護，而(er)不用關心低(di)溫保(bao)護，則(ze)可將R2去掉(diao)，只保(bao)留R1，這(zhe)時R1的計算公(gong)式(shi)變(bian)為：

　　直流適配器(qi)與USB組合的方案

　當(dang)充(chong)電(dian)(dian)(dian)器(qi)需(xu)要直(zhi)流(liu)適(shi)配(pei)器(qi)與USB充(chong)電(dian)(dian)(dian)兩者(zhe)都(dou)能(neng)用時，可(ke)(ke)采用圖5所示(shi)的方案(an)。方案(an)中，假如使用USB口進行供電(dian)(dian)(dian)的話，MOS-P門(men)極接(jie)地(di)，USB電(dian)(dian)(dian)源通過MOS-P導(dao)通至(zhi)(zhi)VCC，同時MOS-N處于關(guan)斷狀態(tai)，PROG上(shang)的編程電(dian)(dian)(dian)阻(zu)為(wei)(wei)2K，即充(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)設定為(wei)(wei)500mA，這樣可(ke)(ke)防(fang)止(zhi)USB接(jie)口被(bei)充(chong)電(dian)(dian)(dian)器(qi)拉死；而當(dang)采用5V直(zhi)流(liu)適(shi)配(pei)器(qi)的時候(hou)，適(shi)配(pei)器(qi)電(dian)(dian)(dian)流(liu)通過肖(xiao)特基二極管加至(zhi)(zhi)VCC腳(jiao)，MOS-P由(you)于門(men)極為(wei)(wei)高電(dian)(dian)(dian)平而被(bei)截止(zhi)，不會對USB口產生影響(xiang)。同時MOS-N由(you)于門(men)極為(wei)(wei)高電(dian)(dian)(dian)平而導(dao)通，此(ci)時PROG腳(jiao)上(shang)的編程電(dian)(dian)(dian)阻(zu)相當(dang)于1K(2個2K電(dian)(dian)(dian)阻(zu)并聯)，即設定充(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)為(wei)(wei)1A，來(lai)對鋰離子電(dian)(dian)(dian)池進行快速充(chong)電(dian)(dian)(dian)。

　　圖5：交(jiao)流適配器與USB組(zu)合的方案。

　　芯片熱保護功能

　　利用(yong)晶體管(guan)PN結的(de)(de)(de)(de)導通電(dian)壓隨(sui)溫度升高而(er)降(jiang)低，而(er)其變化(hua)值隨(sui)溫度的(de)(de)(de)(de)升高而(er)增(zeng)加的(de)(de)(de)(de)特性，AP5056設計了集成于芯(xin)片內部(bu)的(de)(de)(de)(de)過熱保(bao)護功(gong)能(neng)。當內部(bu)溫度傳感器(qi)升至約125℃以(yi)上時，內部(bu)的(de)(de)(de)(de)熱保(bao)護電(dian)路將自動減小充(chong)電(dian)電(dian)流(liu)的(de)(de)(de)(de)電(dian)流(liu)值，隨(sui)著溫度的(de)(de)(de)(de)不斷升高，當溫度達(da)到145℃的(de)(de)(de)(de)時候，則可(ke)完全(quan)關閉充(chong)電(dian)電(dian)流(liu)。該功(gong)能(neng)可(ke)以(yi)讓用(yong)戶放(fang)心(xin)使用(yong)最(zui)大功(gong)率(lv)的(de)(de)(de)(de)充(chong)電(dian)電(dian)流(liu)而(er)無需擔心(xin)芯(xin)片被損(sun)壞。

　　充電狀態指示

　　AP5056有CHRG和(he)STDBY兩(liang)個狀態輸出指(zhi)示。當充(chong)電器(qi)處(chu)于充(chong)電狀態時，CHRG置(zhi)低電平，STDBY輸出高阻態；當電池(chi)處(chu)于充(chong)滿(man)狀態時，CHRG變(bian)為高阻態，STDBY被拉(la)為低電平。

　　如(ru)果不(bu)需要用到狀態指示功能，可以將(jiang)不(bu)用的相應(ying)的狀態輸出指示腳(jiao)接地。

　　指示燈狀態

　　布板的注意事項

　　AP5056采(cai)用SOP8-PP封裝，芯片(pian)(pian)(pian)底部帶有散(san)(san)(san)熱(re)片(pian)(pian)(pian)，以便于(yu)將(jiang)(jiang)芯片(pian)(pian)(pian)工作時產生的(de)熱(re)量(liang)通過散(san)(san)(san)熱(re)片(pian)(pian)(pian)發(fa)散(san)(san)(san)出去，因此，為了(le)達到較好的(de)散(san)(san)(san)熱(re)效果，散(san)(san)(san)熱(re)片(pian)(pian)(pian)下(xia)的(de)PC板銅箔(bo)面(mian)積要盡可能的(de)寬(kuan)闊，并將(jiang)(jiang)之延伸至(zhi)外(wai)面(mian)更大，更寬(kuan)的(de)銅箔(bo)面(mian)積，而且需將(jiang)(jiang)散(san)(san)(san)熱(re)片(pian)(pian)(pian)與散(san)(san)(san), 熱(re)片(pian)(pian)(pian)下(xia)的(de)銅箔(bo)用焊錫焊接(jie)在一起，以增加熱(re)的(de)傳導性(xing)；此外(wai)，利(li)用多個通孔將(jiang)(jiang)上層(ceng)銅箔(bo)與下(xia)層(ceng)銅箔(bo)連接(jie)起來(lai)能夠更有效地拓(tuo)展散(san)(san)(san)熱(re)面(mian)積，有利(li)于(yu)將(jiang)(jiang)熱(re)量(liang)散(san)(san)(san)至(zhi)周(zhou)圍環境(jing)中(zhong)，增加充電芯片(pian)(pian)(pian)的(de)散(san)(san)(san)熱(re)效果(如圖6所(suo)示(shi))。

　　圖(tu)6：AP5056布板示意圖(tu)。

　　在芯片散熱良好的情況下(xia)，AP5056可(ke)提(ti)供電(dian)路最大充(chong)電(dian)電(dian)流(liu)為(wei)1600MA，實驗中，在室溫狀態下(xia)，充(chong)電(dian)電(dian)流(liu)設(she)置為(wei)1600MA，連續工作15分鐘(zhong)，IC表(biao)面溫度(du)為(wei)60℃；設(she)置為(wei)1000MA時，連續工作15分鐘(zhong)，IC表(biao)面溫度(du)為(wei)50℃。

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