電(dian)(dian)電(dian)(dian)流大(da)(da)(da)于電(dian)(dian)池(chi)容(rong)量(liang)的(de)20 隨著當今數碼電(dian)(dian)子(zi)產品功能的(de)不斷增(zeng)加，LCD屏幕越(yue)(yue)來越(yue)(yue)大(da)(da)(da)，以及不斷增(zeng)強的(de)多(duo)媒(mei)體視(shi)屏功能，市面上鋰離子(zi)/聚(ju)合物(wu)電(dian)(dian)池(chi)的(de)容(rong)量(liang)也做得越(yue)(yue)來越(yue)(yue)大(da)(da)(da)。與此(ci)同時(shi)，消(xiao)費(fei)者對縮短(duan)大(da)(da)(da)容(rong)量(liang)電(dian)(dian)池(chi)的(de)充(chong)電(dian)(dian)時(shi)間(jian)提(ti)出了期望。為了能更快速(su)有效地(di)對這些大(da)(da)(da)容(rong)量(liang)電(dian)(dian)池(chi)進行充(chong)電(dian)(dian)，以滿足消(xiao)費(fei)者不斷增(zeng)長的(de)需求，無錫芯朋微電(dian)(dian)子(zi)推出了大(da)(da)(da)電(dian)(dian)流鋰離子(zi)電(dian)(dian)池(chi)充(chong)電(dian)(dian)芯片AP5056。

　　AP5056是可(ke)以(yi)對單節(jie)鋰(li)離子(zi)或鋰(li)聚(ju)合(he)物可(ke)充電(dian)電(dian)池(chi)進行恒流/恒壓充電(dian)的(de)充電(dian)器電(dian)路。器件內部采用PMOSFET架構，應用時不(bu)需要外部另加阻流二極管。熱(re)反饋(kui)電(dian)路可(ke)以(yi)自(zi)動調節(jie)充電(dian)電(dian)流，使(shi)器件在功(gong)耗(hao)比較(jiao)大或者環境(jing)溫度比較(jiao)高的(de)情況下將芯片溫度控制在安全范圍內。

　　AP5056只需要極少(shao)的外圍元器件，可以適(shi)應USB 電(dian)源(yuan)和(he)適(shi)配器電(dian)源(yuan)工作，非常(chang)適(shi)用于便攜(xie)式(shi)應用的領域(yu)。充(chong)(chong)電(dian)輸(shu)出電(dian)壓為(wei)4.2V，充(chong)(chong)電(dian)電(dian)流的大小可以通過一個外部電(dian)阻設(she)置。在(zai)恒壓充(chong)(chong)電(dian)階段中(zhong)，當(dang)充(chong)(chong)電(dian)電(dian)流降(jiang)至(zhi)設(she)定(ding)值1/10 時(shi)，AP5056將終止充(chong)(chong)電(dian)循環。

　　當輸入(ru)電(dian)壓(交流適配器或(huo)者USB電(dian)源)掉電(dian)時，AP5056自動進入(ru)低(di)功耗的睡眠模式，此(ci)時電(dian)池的電(dian)流消耗小于2微安。其它功能包括輸入(ru)電(dian)壓過低(di)鎖存、芯片使(shi)能輸入(ru)、自動再充電(dian)、電(dian)池溫度監控以及狀態指示等功能。

　　充(chong)電(dian)(dian)過(guo)程：AP5056在整個電(dian)(dian)池(chi)充(chong)電(dian)(dian)過(guo)程中有四種基(ji)本充(chong)電(dian)(dian)模式：涓流充(chong)電(dian)(dian)、恒流充(chong)電(dian)(dian)、恒壓充(chong)電(dian)(dian)和充(chong)電(dian)(dian)完成(cheng)與再充(chong)電(dian)(dian)。

　　涓(juan)(juan)流(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)：充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)開(kai)始前，AP5056先(xian)檢(jian)查(cha)輸入(ru)電(dian)(dian)(dian)(dian)源(yuan)(yuan)，當輸入(ru)電(dian)(dian)(dian)(dian)源(yuan)(yuan)大于最小工(gong)作電(dian)(dian)(dian)(dian)壓或欠壓鎖(suo)定(ding)閾值，并且芯片使能(neng)端接高電(dian)(dian)(dian)(dian)平(ping)時(shi)，AP5056開(kai)始對電(dian)(dian)(dian)(dian)池(chi)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)。AP5056先(xian)檢(jian)查(cha)電(dian)(dian)(dian)(dian)池(chi)的狀態(tai)。如(ru)果電(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)壓高于3V，充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)器則進入(ru)恒(heng)(heng)流(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)；而如(ru)果電(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)壓低于3V時(shi)，充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)器則進入(ru)涓(juan)(juan)流(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)模式。涓(juan)(juan)流(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)是恒(heng)(heng)流(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)的十分(fen)之一(還是以(yi)恒(heng)(heng)定(ding)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)為1A舉例(li)，則涓(juan)(juan)流(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)為100mA)，涓(juan)(juan)流(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)狀態(tai)一直(zhi)保持延續到AP5056芯片探(tan)測到電(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)壓達到3V后結(jie)束，之后進入(ru)恒(heng)(heng)流(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)階段。

　　圖2：AP5056封裝。

　　恒流充電(dian)：恒流充電(dian)模式(shi)中，充電(dian)電(dian)流由(you)PROG腳與GND間的電(dian)阻(zu)RPROG確定。(參見下文“可(ke)編程的充電(dian)電(dian)流”)

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

　　AP5056進入恒(heng)流(liu)(liu)(liu)充(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)模(mo)式(shi)中后，將一直(zhi)按設定的(de)(de)電(dian)(dian)(dian)流(liu)(liu)(liu)值保持充(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)，直(zhi)到(dao)電(dian)(dian)(dian)池(chi)(chi)(chi)慢(man)慢(man)到(dao)達電(dian)(dian)(dian)壓(ya)調節點4.2V，轉(zhuan)而進入恒(heng)壓(ya)充(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)。恒(heng)壓(ya)充(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)：在電(dian)(dian)(dian)池(chi)(chi)(chi)電(dian)(dian)(dian)壓(ya)慢(man)慢(man)接(jie)近(jin)4.2V時，充(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)器就(jiu)漸(jian)漸(jian)轉(zhuan)為恒(heng)壓(ya)充(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)。此時原先的(de)(de)恒(heng)流(liu)(liu)(liu)充(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)(liu)(liu)也(ye)慢(man)慢(man)減(jian)小(xiao)(xiao)，并隨著電(dian)(dian)(dian)池(chi)(chi)(chi)容量越來越接(jie)近(jin)最大容量而急(ji)劇下降。 充(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)完(wan)成與再充(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)：當(dang)充(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)(liu)(liu)被探測到(dao)減(jian)小(xiao)(xiao)至(zhi)恒(heng)流(liu)(liu)(liu)充(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)(liu)(liu)的(de)(de)10%后，充(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)器終(zhong)止向(xiang)電(dian)(dian)(dian)池(chi)(chi)(chi)充(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)，進入低功耗(hao)的(de)(de)待(dai)機(ji)模(mo)式(shi)。 在待(dai)機(ji)模(mo)式(shi)下，AP5056會(hui)繼續(xu)檢測電(dian)(dian)(dian)池(chi)(chi)(chi)端的(de)(de)電(dian)(dian)(dian)壓(ya)，如果電(dian)(dian)(dian)池(chi)(chi)(chi)電(dian)(dian)(dian)壓(ya)降到(dao)4.05V以下，則(ze)充(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)器將再次(ci)向(xiang)電(dian)(dian)(dian)池(chi)(chi)(chi)充(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)。

　　可編(bian)程的充(chong)電(dian)電(dian)流：AP5056的充(chong)電(dian)電(dian)流由連接在(zai)PROG腳與GND之間RPROG電(dian)阻來確(que)定，計算公式如下：

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

　　例如，客戶需(xu)要得(de)到(dao)一個(ge)1A的充(chong)電電流的話，根據公(gong)式得(de)到(dao)

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

　　圖3顯示了RPROG為1K和2K時，不同的電源輸入Vcc 與(yu)充電電流Ibat之間的關系(xi)圖，可以看到充電輸出電流基(ji)本沒有很大變化，只與(yu)RPROG的設定值(zhi)有關系(xi)。

　　圖3：電源輸(shu)入Vcc VS 充電電流Ibat。

　　典型應用電路

　　圖4給出的(de)(de)是(shi)典(dian)型的(de)(de)應用電(dian)(dian)路(lu)，電(dian)(dian)路(lu)中R1, R2由(you)NTC熱(re)敏(min)電(dian)(dian)阻(zu)值(zhi)(zhi)來(lai)確定。設熱(re)敏(min)電(dian)(dian)阻(zu)在最低(di)工(gong)(gong)作溫度(du)時(shi)的(de)(de)電(dian)(dian)阻(zu)為RTL，在最高工(gong)(gong)作溫度(du)時(shi)的(de)(de)電(dian)(dian)阻(zu)為RTH(RTL與(yu)RTH的(de)(de)數據可查電(dian)(dian)池(chi)廠方數據或做(zuo)實驗得到(dao))，則R1，R2的(de)(de)阻(zu)值(zhi)(zhi)分(fen)別為：

　　圖4：AP5056應用電路(lu)。

　　如果用戶只(zhi)關心高溫(wen)保(bao)護(hu)，而不(bu)用關心低溫(wen)保(bao)護(hu)，則可將R2去(qu)掉，只(zhi)保(bao)留R1，這時(shi)R1的計算公式變為：

　　直流適配器與USB組(zu)合的方(fang)案

　當(dang)充(chong)電(dian)(dian)(dian)(dian)(dian)器(qi)(qi)需要直(zhi)流適(shi)配器(qi)(qi)與(yu)USB充(chong)電(dian)(dian)(dian)(dian)(dian)兩者都能用(yong)時，可(ke)(ke)采(cai)用(yong)圖(tu)5所示(shi)的(de)方案。方案中(zhong)，假如使用(yong)USB口(kou)進(jin)行供(gong)電(dian)(dian)(dian)(dian)(dian)的(de)話，MOS-P門(men)極接(jie)地，USB電(dian)(dian)(dian)(dian)(dian)源通(tong)(tong)過(guo)MOS-P導通(tong)(tong)至(zhi)(zhi)VCC，同時MOS-N處(chu)于(yu)關斷狀(zhuang)態(tai)，PROG上(shang)的(de)編程電(dian)(dian)(dian)(dian)(dian)阻(zu)為(wei)(wei)2K，即充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流設(she)定為(wei)(wei)500mA，這樣可(ke)(ke)防止USB接(jie)口(kou)被(bei)充(chong)電(dian)(dian)(dian)(dian)(dian)器(qi)(qi)拉死；而當(dang)采(cai)用(yong)5V直(zhi)流適(shi)配器(qi)(qi)的(de)時候(hou)，適(shi)配器(qi)(qi)電(dian)(dian)(dian)(dian)(dian)流通(tong)(tong)過(guo)肖特基二極管(guan)加至(zhi)(zhi)VCC腳，MOS-P由于(yu)門(men)極為(wei)(wei)高電(dian)(dian)(dian)(dian)(dian)平而被(bei)截止，不會(hui)對USB口(kou)產生影(ying)響(xiang)。同時MOS-N由于(yu)門(men)極為(wei)(wei)高電(dian)(dian)(dian)(dian)(dian)平而導通(tong)(tong)，此(ci)時PROG腳上(shang)的(de)編程電(dian)(dian)(dian)(dian)(dian)阻(zu)相當(dang)于(yu)1K(2個2K電(dian)(dian)(dian)(dian)(dian)阻(zu)并聯)，即設(she)定充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流為(wei)(wei)1A，來對鋰離(li)子(zi)電(dian)(dian)(dian)(dian)(dian)池進(jin)行快速(su)充(chong)電(dian)(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

　　利用晶(jing)體管PN結(jie)的導通電(dian)(dian)(dian)(dian)壓隨(sui)(sui)溫(wen)度(du)(du)升(sheng)(sheng)(sheng)高(gao)而(er)(er)降低(di)，而(er)(er)其(qi)變(bian)化值隨(sui)(sui)溫(wen)度(du)(du)的升(sheng)(sheng)(sheng)高(gao)而(er)(er)增加的特(te)性，AP5056設(she)計了集(ji)成于芯片內(nei)部的過熱保(bao)護(hu)功(gong)(gong)能(neng)。當內(nei)部溫(wen)度(du)(du)傳感(gan)器升(sheng)(sheng)(sheng)至約(yue)125℃以上時，內(nei)部的熱保(bao)護(hu)電(dian)(dian)(dian)(dian)路將自動減小充電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流的電(dian)(dian)(dian)(dian)流值，隨(sui)(sui)著溫(wen)度(du)(du)的不斷升(sheng)(sheng)(sheng)高(gao)，當溫(wen)度(du)(du)達(da)到145℃的時候，則可(ke)(ke)完(wan)全關閉充電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流。該功(gong)(gong)能(neng)可(ke)(ke)以讓(rang)用戶放心(xin)(xin)使用最大功(gong)(gong)率(lv)的充電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流而(er)(er)無(wu)需擔心(xin)(xin)芯片被(bei)損壞。

　　充電狀態指示

　　AP5056有CHRG和STDBY兩個狀(zhuang)態輸出(chu)指示。當(dang)充電(dian)器處于充電(dian)狀(zhuang)態時(shi)，CHRG置低電(dian)平，STDBY輸出(chu)高阻態；當(dang)電(dian)池處于充滿狀(zhuang)態時(shi)，CHRG變(bian)為(wei)高阻態，STDBY被拉為(wei)低電(dian)平。

　　如(ru)果不需(xu)要用到狀態指示功能，可以(yi)將不用的相(xiang)應的狀態輸出指示腳接地。

　　指示燈狀態

　　布板的注意事項

　　AP5056采(cai)用(yong)SOP8-PP封裝，芯(xin)片(pian)(pian)底部帶有散(san)(san)(san)熱(re)(re)片(pian)(pian)，以(yi)便(bian)于將(jiang)(jiang)芯(xin)片(pian)(pian)工作時(shi)產生的(de)(de)(de)熱(re)(re)量(liang)通過(guo)散(san)(san)(san)熱(re)(re)片(pian)(pian)發散(san)(san)(san)出去，因此，為了達到較好的(de)(de)(de)散(san)(san)(san)熱(re)(re)效(xiao)(xiao)果(guo)，散(san)(san)(san)熱(re)(re)片(pian)(pian)下的(de)(de)(de)PC板銅(tong)(tong)(tong)箔(bo)面(mian)積(ji)要盡可(ke)能的(de)(de)(de)寬闊，并將(jiang)(jiang)之延伸至(zhi)外面(mian)更(geng)大，更(geng)寬的(de)(de)(de)銅(tong)(tong)(tong)箔(bo)面(mian)積(ji)，而且需將(jiang)(jiang)散(san)(san)(san)熱(re)(re)片(pian)(pian)與(yu)散(san)(san)(san), 熱(re)(re)片(pian)(pian)下的(de)(de)(de)銅(tong)(tong)(tong)箔(bo)用(yong)焊(han)錫焊(han)接(jie)在一起，以(yi)增加(jia)熱(re)(re)的(de)(de)(de)傳導(dao)性；此外，利用(yong)多個通孔將(jiang)(jiang)上(shang)層銅(tong)(tong)(tong)箔(bo)與(yu)下層銅(tong)(tong)(tong)箔(bo)連接(jie)起來能夠更(geng)有效(xiao)(xiao)地拓展(zhan)散(san)(san)(san)熱(re)(re)面(mian)積(ji)，有利于將(jiang)(jiang)熱(re)(re)量(liang)散(san)(san)(san)至(zhi)周圍(wei)環境中，增加(jia)充電芯(xin)片(pian)(pian)的(de)(de)(de)散(san)(san)(san)熱(re)(re)效(xiao)(xiao)果(guo)(如圖6所(suo)示)。

　　圖6：AP5056布板示意圖。

　　在芯(xin)片(pian)散熱(re)良好的情(qing)況下，AP5056可(ke)提(ti)供電路最大充電電流為(wei)(wei)1600MA，實驗中，在室(shi)溫(wen)狀(zhuang)態下，充電電流設置為(wei)(wei)1600MA，連續(xu)工作15分鐘，IC表(biao)面溫(wen)度(du)為(wei)(wei)60℃；設置為(wei)(wei)1000MA時，連續(xu)工作15分鐘，IC表(biao)面溫(wen)度(du)為(wei)(wei)50℃。

％時：
充(chong)電(dian)時間（小時）＝電(dian)池容(rong)量（mAH）×1.1÷充(chong)電(dian)電(dian)流(mA)