電(dian)(dian)電(dian)(dian)流大于電(dian)(dian)池(chi)容(rong)量(liang)(liang)(liang)的(de)20 隨著當今(jin)數碼電(dian)(dian)子產品功能(neng)的(de)不斷(duan)增(zeng)加，LCD屏(ping)幕越(yue)(yue)來越(yue)(yue)大，以及不斷(duan)增(zeng)強的(de)多媒(mei)體視(shi)屏(ping)功能(neng)，市面(mian)上鋰離(li)子/聚合(he)物電(dian)(dian)池(chi)的(de)容(rong)量(liang)(liang)(liang)也做得越(yue)(yue)來越(yue)(yue)大。與此同時，消費者(zhe)對縮短(duan)大容(rong)量(liang)(liang)(liang)電(dian)(dian)池(chi)的(de)充(chong)電(dian)(dian)時間提出了(le)期(qi)望。為(wei)了(le)能(neng)更快速(su)有效地對這些大容(rong)量(liang)(liang)(liang)電(dian)(dian)池(chi)進行充(chong)電(dian)(dian)，以滿(man)足消費者(zhe)不斷(duan)增(zeng)長的(de)需(xu)求，無錫芯朋微電(dian)(dian)子推出了(le)大電(dian)(dian)流鋰離(li)子電(dian)(dian)池(chi)充(chong)電(dian)(dian)芯片AP5056。

　　AP5056是可以對單節鋰(li)離子或鋰(li)聚(ju)合物可充電電池(chi)進行恒(heng)流/恒(heng)壓充電的充電器電路。器件內(nei)(nei)部采(cai)用(yong)PMOSFET架構(gou)，應(ying)用(yong)時不(bu)需要(yao)外部另加(jia)阻流二極管。熱(re)反饋電路可以自動調節充電電流，使(shi)器件在功耗比(bi)較大或者環境溫度(du)比(bi)較高的情況下將芯(xin)片溫度(du)控制在安全范圍內(nei)(nei)。

　　AP5056只需要極(ji)少的(de)外圍元器(qi)件，可(ke)以適應USB 電(dian)源和適配器(qi)電(dian)源工作，非常適用(yong)于(yu)便攜(xie)式應用(yong)的(de)領域。充(chong)電(dian)輸出電(dian)壓為4.2V，充(chong)電(dian)電(dian)流(liu)的(de)大小可(ke)以通過一(yi)個(ge)外部電(dian)阻設置。在恒壓充(chong)電(dian)階段中，當充(chong)電(dian)電(dian)流(liu)降至(zhi)設定值1/10 時，AP5056將終止(zhi)充(chong)電(dian)循環。

　　當輸入(ru)(ru)電(dian)(dian)壓(交(jiao)流適配器(qi)或者USB電(dian)(dian)源)掉電(dian)(dian)時，AP5056自動(dong)進(jin)入(ru)(ru)低功耗的(de)睡眠模式，此時電(dian)(dian)池的(de)電(dian)(dian)流消耗小于2微安(an)。其它(ta)功能(neng)包括輸入(ru)(ru)電(dian)(dian)壓過低鎖存、芯片(pian)使能(neng)輸入(ru)(ru)、自動(dong)再充電(dian)(dian)、電(dian)(dian)池溫度監控以及狀態指示(shi)等功能(neng)。

　　充(chong)電(dian)(dian)(dian)過程(cheng)(cheng)：AP5056在整個電(dian)(dian)(dian)池充(chong)電(dian)(dian)(dian)過程(cheng)(cheng)中有四種基(ji)本充(chong)電(dian)(dian)(dian)模(mo)式：涓流(liu)充(chong)電(dian)(dian)(dian)、恒流(liu)充(chong)電(dian)(dian)(dian)、恒壓充(chong)電(dian)(dian)(dian)和充(chong)電(dian)(dian)(dian)完成與再充(chong)電(dian)(dian)(dian)。

　　涓流(liu)(liu)(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)：充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)開(kai)始(shi)前，AP5056先檢查輸入(ru)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源，當輸入(ru)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源大于最(zui)小(xiao)工作電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)或(huo)欠壓(ya)(ya)鎖定閾值(zhi)，并且芯片使能端接高電(dian)(dian)(dian)(dian)(dian)(dian)(dian)平時，AP5056開(kai)始(shi)對電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)。AP5056先檢查電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)的狀態。如果(guo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)高于3V，充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)器(qi)則(ze)進(jin)入(ru)恒流(liu)(liu)(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)；而(er)如果(guo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)低(di)于3V時，充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)器(qi)則(ze)進(jin)入(ru)涓流(liu)(liu)(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)模式。涓流(liu)(liu)(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)是恒流(liu)(liu)(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)的十分之(zhi)一(還(huan)是以恒定充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)為1A舉例，則(ze)涓流(liu)(liu)(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)為100mA)，涓流(liu)(liu)(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)狀態一直保持延續到(dao)AP5056芯片探測(ce)到(dao)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)達到(dao)3V后結(jie)束，之(zhi)后進(jin)入(ru)恒流(liu)(liu)(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)階(jie)段。

　　圖2：AP5056封裝。

　　恒流(liu)充(chong)(chong)電(dian)(dian)：恒流(liu)充(chong)(chong)電(dian)(dian)模式中，充(chong)(chong)電(dian)(dian)電(dian)(dian)流(liu)由PROG腳(jiao)與GND間(jian)的電(dian)(dian)阻(zu)RPROG確定。(參見下(xia)文“可編程的充(chong)(chong)電(dian)(dian)電(dian)(dian)流(liu)”)

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

　　AP5056進入(ru)恒流充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)模(mo)式(shi)中(zhong)后，將一直按(an)設定的(de)(de)電(dian)(dian)(dian)(dian)(dian)流值保持充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)，直到(dao)(dao)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)慢(man)(man)慢(man)(man)到(dao)(dao)達電(dian)(dian)(dian)(dian)(dian)壓(ya)調節(jie)點(dian)4.2V，轉而(er)進入(ru)恒壓(ya)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)。恒壓(ya)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)：在(zai)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)壓(ya)慢(man)(man)慢(man)(man)接近(jin)4.2V時(shi)，充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)器(qi)(qi)(qi)就漸漸轉為恒壓(ya)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)。此時(shi)原先的(de)(de)恒流充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流也慢(man)(man)慢(man)(man)減小，并(bing)隨(sui)著電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)容量越來越接近(jin)最大容量而(er)急劇下(xia)降。 充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)完成(cheng)與再充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)：當充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流被探測到(dao)(dao)減小至(zhi)恒流充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流的(de)(de)10%后，充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)器(qi)(qi)(qi)終(zhong)止向電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)，進入(ru)低功(gong)耗的(de)(de)待機模(mo)式(shi)。 在(zai)待機模(mo)式(shi)下(xia)，AP5056會繼(ji)續(xu)檢測電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)端(duan)的(de)(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)，如果(guo)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)壓(ya)降到(dao)(dao)4.05V以下(xia)，則充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)器(qi)(qi)(qi)將再次向電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)。

　　可編(bian)程的(de)充電(dian)電(dian)流：AP5056的(de)充電(dian)電(dian)流由連(lian)接在(zai)PROG腳與GND之間RPROG電(dian)阻來確定，計算公式如下(xia)：

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

　　例如，客戶需(xu)要得到(dao)一個(ge)1A的充電電流的話，根據(ju)公式得到(dao)

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

　　圖3顯(xian)示了RPROG為1K和(he)2K時(shi)，不同的(de)(de)電(dian)(dian)(dian)源(yuan)輸入Vcc 與充電(dian)(dian)(dian)電(dian)(dian)(dian)流Ibat之(zhi)間的(de)(de)關(guan)系圖，可(ke)以看到充電(dian)(dian)(dian)輸出電(dian)(dian)(dian)流基本沒有很大變化，只與RPROG的(de)(de)設(she)定值(zhi)有關(guan)系。

　　圖3：電源(yuan)輸入(ru)Vcc VS 充電電流Ibat。

　　典型應用電路

　　圖(tu)4給出的(de)是典型的(de)應用電(dian)(dian)(dian)路，電(dian)(dian)(dian)路中R1, R2由NTC熱敏電(dian)(dian)(dian)阻(zu)(zu)值(zhi)來確定。設熱敏電(dian)(dian)(dian)阻(zu)(zu)在(zai)最低工(gong)作溫度時(shi)的(de)電(dian)(dian)(dian)阻(zu)(zu)為(wei)RTL，在(zai)最高(gao)工(gong)作溫度時(shi)的(de)電(dian)(dian)(dian)阻(zu)(zu)為(wei)RTH(RTL與RTH的(de)數(shu)據可查電(dian)(dian)(dian)池廠方(fang)數(shu)據或做實驗得到)，則R1，R2的(de)阻(zu)(zu)值(zhi)分(fen)別為(wei)：

　　圖4：AP5056應用(yong)電路。

　　如(ru)果(guo)用(yong)戶只(zhi)關心高(gao)溫保(bao)(bao)護(hu)，而(er)不用(yong)關心低溫保(bao)(bao)護(hu)，則可將R2去掉，只(zhi)保(bao)(bao)留R1，這時R1的計算公式變為：

　　直(zhi)流適配器與USB組(zu)合的方案(an)

　當充(chong)電(dian)(dian)(dian)(dian)器(qi)(qi)(qi)需(xu)要直(zhi)流適配器(qi)(qi)(qi)與USB充(chong)電(dian)(dian)(dian)(dian)兩(liang)者(zhe)都能用時，可(ke)(ke)采用圖5所示的方案。方案中，假如(ru)使(shi)用USB口(kou)(kou)進行供電(dian)(dian)(dian)(dian)的話，MOS-P門(men)極(ji)接(jie)地(di)，USB電(dian)(dian)(dian)(dian)源通過MOS-P導(dao)通至VCC，同(tong)(tong)時MOS-N處于(yu)(yu)關斷狀態(tai)，PROG上(shang)的編程(cheng)電(dian)(dian)(dian)(dian)阻(zu)為(wei)2K，即充(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流設定(ding)為(wei)500mA，這樣可(ke)(ke)防(fang)止USB接(jie)口(kou)(kou)被充(chong)電(dian)(dian)(dian)(dian)器(qi)(qi)(qi)拉(la)死；而當采用5V直(zhi)流適配器(qi)(qi)(qi)的時候，適配器(qi)(qi)(qi)電(dian)(dian)(dian)(dian)流通過肖特基二極(ji)管加(jia)至VCC腳(jiao)，MOS-P由于(yu)(yu)門(men)極(ji)為(wei)高(gao)電(dian)(dian)(dian)(dian)平而被截止，不會對USB口(kou)(kou)產生影響(xiang)。同(tong)(tong)時MOS-N由于(yu)(yu)門(men)極(ji)為(wei)高(gao)電(dian)(dian)(dian)(dian)平而導(dao)通，此(ci)時PROG腳(jiao)上(shang)的編程(cheng)電(dian)(dian)(dian)(dian)阻(zu)相當于(yu)(yu)1K(2個2K電(dian)(dian)(dian)(dian)阻(zu)并聯)，即設定(ding)充(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流為(wei)1A，來(lai)對鋰離子電(dian)(dian)(dian)(dian)池(chi)進行快(kuai)速充(chong)電(dian)(dian)(dian)(dian)。

　　圖5：交流適配器(qi)與USB組合的方案。

　　芯片熱保護功能

　　利用晶(jing)體管(guan)PN結(jie)的(de)(de)導通電(dian)(dian)壓隨(sui)溫(wen)(wen)度(du)升(sheng)(sheng)高而降(jiang)低，而其變化值(zhi)隨(sui)溫(wen)(wen)度(du)的(de)(de)升(sheng)(sheng)高而增加(jia)的(de)(de)特(te)性(xing)，AP5056設計了集(ji)成于芯(xin)片(pian)內部的(de)(de)過熱保(bao)(bao)護(hu)功(gong)能(neng)。當內部溫(wen)(wen)度(du)傳感(gan)器升(sheng)(sheng)至約125℃以上時，內部的(de)(de)熱保(bao)(bao)護(hu)電(dian)(dian)路將自動減小充電(dian)(dian)電(dian)(dian)流(liu)的(de)(de)電(dian)(dian)流(liu)值(zhi)，隨(sui)著溫(wen)(wen)度(du)的(de)(de)不斷升(sheng)(sheng)高，當溫(wen)(wen)度(du)達(da)到145℃的(de)(de)時候，則可完全關閉充電(dian)(dian)電(dian)(dian)流(liu)。該功(gong)能(neng)可以讓用戶放心(xin)使用最大功(gong)率的(de)(de)充電(dian)(dian)電(dian)(dian)流(liu)而無(wu)需擔(dan)心(xin)芯(xin)片(pian)被損壞。

　　充電狀態指示

　　AP5056有CHRG和STDBY兩(liang)個狀態(tai)輸出(chu)指(zhi)示。當充電器處于充電狀態(tai)時(shi)，CHRG置低電平，STDBY輸出(chu)高阻態(tai)；當電池處于充滿狀態(tai)時(shi)，CHRG變為高阻態(tai)，STDBY被拉為低電平。

　　如果不需要(yao)用(yong)到狀態(tai)指示功能，可以將不用(yong)的(de)相應的(de)狀態(tai)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(xin)片底部帶有(you)散(san)熱(re)(re)片，以便于(yu)將(jiang)芯(xin)片工作(zuo)時產生(sheng)的(de)熱(re)(re)量(liang)通過散(san)熱(re)(re)片發散(san)出去，因(yin)此，為了達到較好(hao)的(de)散(san)熱(re)(re)效(xiao)(xiao)(xiao)果，散(san)熱(re)(re)片下的(de)PC板銅(tong)箔(bo)(bo)面積要盡可能的(de)寬闊，并(bing)將(jiang)之延伸(shen)至外面更大(da)，更寬的(de)銅(tong)箔(bo)(bo)面積，而且需將(jiang)散(san)熱(re)(re)片與(yu)散(san), 熱(re)(re)片下的(de)銅(tong)箔(bo)(bo)用焊錫焊接在一(yi)起(qi)，以增(zeng)加熱(re)(re)的(de)傳導性；此外，利(li)用多個通孔(kong)將(jiang)上層銅(tong)箔(bo)(bo)與(yu)下層銅(tong)箔(bo)(bo)連(lian)接起(qi)來能夠更有(you)效(xiao)(xiao)(xiao)地拓展散(san)熱(re)(re)面積，有(you)利(li)于(yu)將(jiang)熱(re)(re)量(liang)散(san)至周圍(wei)環境中，增(zeng)加充電芯(xin)片的(de)散(san)熱(re)(re)效(xiao)(xiao)(xiao)果(如圖6所示)。

　　圖6：AP5056布板示意圖。

　　在(zai)芯片散熱良好的情況下，AP5056可(ke)提供電路(lu)最大充電電流為1600MA，實驗中，在(zai)室溫狀態(tai)下，充電電流設置為1600MA，連(lian)續工(gong)作(zuo)15分鐘，IC表(biao)面溫度為60℃；設置為1000MA時，連(lian)續工(gong)作(zuo)15分鐘，IC表(biao)面溫度為50℃。

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