電(dian)(dian)電(dian)(dian)流大(da)(da)于電(dian)(dian)池容(rong)(rong)量的(de)20 隨著當(dang)今(jin)數(shu)碼電(dian)(dian)子產品(pin)功能(neng)的(de)不(bu)斷增(zeng)加，LCD屏(ping)幕越(yue)(yue)來(lai)越(yue)(yue)大(da)(da)，以(yi)(yi)及不(bu)斷增(zeng)強的(de)多媒體視屏(ping)功能(neng)，市面(mian)上鋰(li)離子/聚合物(wu)電(dian)(dian)池的(de)容(rong)(rong)量也(ye)做(zuo)得越(yue)(yue)來(lai)越(yue)(yue)大(da)(da)。與此同時(shi)(shi)，消(xiao)費者對縮短大(da)(da)容(rong)(rong)量電(dian)(dian)池的(de)充電(dian)(dian)時(shi)(shi)間提出了(le)(le)期望。為了(le)(le)能(neng)更快速有效地對這些(xie)大(da)(da)容(rong)(rong)量電(dian)(dian)池進行充電(dian)(dian)，以(yi)(yi)滿足消(xiao)費者不(bu)斷增(zeng)長的(de)需求，無錫芯朋微電(dian)(dian)子推出了(le)(le)大(da)(da)電(dian)(dian)流鋰(li)離子電(dian)(dian)池充電(dian)(dian)芯片AP5056。

　　AP5056是可以對單節鋰(li)離子或鋰(li)聚合(he)物(wu)可充電(dian)(dian)電(dian)(dian)池(chi)進(jin)行恒(heng)流(liu)/恒(heng)壓充電(dian)(dian)的(de)充電(dian)(dian)器(qi)電(dian)(dian)路。器(qi)件(jian)內部采用(yong)PMOSFET架構，應用(yong)時不需(xu)要外部另加阻流(liu)二極管。熱反(fan)饋電(dian)(dian)路可以自動調節充電(dian)(dian)電(dian)(dian)流(liu)，使器(qi)件(jian)在功耗比較大或者環境溫度比較高的(de)情況下將芯片溫度控制在安全范圍內。

　　AP5056只需要極少的外圍元器(qi)(qi)件，可以(yi)適(shi)應USB 電(dian)(dian)(dian)(dian)源(yuan)和適(shi)配(pei)器(qi)(qi)電(dian)(dian)(dian)(dian)源(yuan)工作，非常適(shi)用于便攜式應用的領(ling)域。充電(dian)(dian)(dian)(dian)輸(shu)出電(dian)(dian)(dian)(dian)壓為4.2V，充電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)的大小可以(yi)通過(guo)一(yi)個外部電(dian)(dian)(dian)(dian)阻設(she)置。在恒壓充電(dian)(dian)(dian)(dian)階(jie)段(duan)中(zhong)，當充電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)降至設(she)定(ding)值1/10 時，AP5056將終止充電(dian)(dian)(dian)(dian)循(xun)環。

　　當輸入電(dian)壓(交(jiao)流適配(pei)器或者USB電(dian)源(yuan))掉電(dian)時，AP5056自動進入低(di)功(gong)耗的(de)睡眠(mian)模式，此時電(dian)池的(de)電(dian)流消(xiao)耗小于2微安。其它功(gong)能包(bao)括輸入電(dian)壓過低(di)鎖(suo)存、芯(xin)片(pian)使能輸入、自動再充(chong)電(dian)、電(dian)池溫(wen)度監控以及狀(zhuang)態指示等功(gong)能。

　　充(chong)電(dian)過程(cheng)(cheng)：AP5056在整個(ge)電(dian)池充(chong)電(dian)過程(cheng)(cheng)中有四種基本(ben)充(chong)電(dian)模式(shi)：涓流(liu)充(chong)電(dian)、恒(heng)流(liu)充(chong)電(dian)、恒(heng)壓充(chong)電(dian)和充(chong)電(dian)完成與再(zai)充(chong)電(dian)。

　　涓流(liu)(liu)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)：充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)開始前，AP5056先檢查(cha)輸入(ru)(ru)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源，當輸入(ru)(ru)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源大于最小工作電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)或欠壓(ya)鎖定(ding)閾(yu)值，并且芯(xin)片使能端(duan)接高(gao)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)平(ping)時(shi)，AP5056開始對電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)。AP5056先檢查(cha)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)的(de)狀態。如果電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)高(gao)于3V，充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)器則進入(ru)(ru)恒(heng)流(liu)(liu)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)；而(er)如果電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)低于3V時(shi)，充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)器則進入(ru)(ru)涓流(liu)(liu)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)模(mo)式。涓流(liu)(liu)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)是(shi)恒(heng)流(liu)(liu)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)的(de)十分之一(還是(shi)以恒(heng)定(ding)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)為1A舉例，則涓流(liu)(liu)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)為100mA)，涓流(liu)(liu)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)狀態一直保持延(yan)續(xu)到(dao)AP5056芯(xin)片探(tan)測到(dao)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)達到(dao)3V后結(jie)束，之后進入(ru)(ru)恒(heng)流(liu)(liu)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)階段。

　　圖2：AP5056封裝。

　　恒(heng)流充(chong)電：恒(heng)流充(chong)電模式中，充(chong)電電流由PROG腳與GND間的電阻(zu)RPROG確定。(參見下(xia)文“可編程的充(chong)電電流”)

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

　　AP5056進(jin)入恒(heng)流(liu)(liu)(liu)充(chong)電(dian)(dian)(dian)(dian)模(mo)式(shi)(shi)(shi)中(zhong)后，將(jiang)一(yi)直(zhi)按設定的(de)(de)電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)值保持(chi)充(chong)電(dian)(dian)(dian)(dian)，直(zhi)到電(dian)(dian)(dian)(dian)池(chi)慢(man)(man)慢(man)(man)到達電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)調節(jie)點4.2V，轉(zhuan)而(er)進(jin)入恒(heng)壓(ya)(ya)(ya)(ya)充(chong)電(dian)(dian)(dian)(dian)。恒(heng)壓(ya)(ya)(ya)(ya)充(chong)電(dian)(dian)(dian)(dian)：在電(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)慢(man)(man)慢(man)(man)接近(jin)(jin)4.2V時，充(chong)電(dian)(dian)(dian)(dian)器(qi)就(jiu)漸漸轉(zhuan)為恒(heng)壓(ya)(ya)(ya)(ya)充(chong)電(dian)(dian)(dian)(dian)。此時原先的(de)(de)恒(heng)流(liu)(liu)(liu)充(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)也慢(man)(man)慢(man)(man)減(jian)小，并隨著電(dian)(dian)(dian)(dian)池(chi)容(rong)量越來(lai)越接近(jin)(jin)最(zui)大容(rong)量而(er)急(ji)劇下(xia)降(jiang)。 充(chong)電(dian)(dian)(dian)(dian)完成(cheng)與再充(chong)電(dian)(dian)(dian)(dian)：當充(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)被探測(ce)到減(jian)小至恒(heng)流(liu)(liu)(liu)充(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)的(de)(de)10%后，充(chong)電(dian)(dian)(dian)(dian)器(qi)終止向(xiang)電(dian)(dian)(dian)(dian)池(chi)充(chong)電(dian)(dian)(dian)(dian)，進(jin)入低(di)功耗的(de)(de)待機模(mo)式(shi)(shi)(shi)。 在待機模(mo)式(shi)(shi)(shi)下(xia)，AP5056會繼續(xu)檢測(ce)電(dian)(dian)(dian)(dian)池(chi)端的(de)(de)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)，如果(guo)電(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)降(jiang)到4.05V以下(xia)，則(ze)充(chong)電(dian)(dian)(dian)(dian)器(qi)將(jiang)再次(ci)向(xiang)電(dian)(dian)(dian)(dian)池(chi)充(chong)電(dian)(dian)(dian)(dian)。

　　可(ke)編程的充電(dian)電(dian)流(liu)：AP5056的充電(dian)電(dian)流(liu)由連接在PROG腳與GND之間RPROG電(dian)阻(zu)來確定，計算公式(shi)如(ru)下：

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

　　例如，客戶需要得(de)到(dao)一個(ge)1A的充電電流的話(hua)，根據公式得(de)到(dao)

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

　　圖3顯示了RPROG為(wei)1K和(he)2K時，不同的電(dian)源輸入(ru)Vcc 與充電(dian)電(dian)流Ibat之間的關(guan)系圖，可以看到充電(dian)輸出電(dian)流基本沒有很大(da)變化，只與RPROG的設定(ding)值有關(guan)系。

　　圖3：電源輸入Vcc VS 充(chong)電電流(liu)Ibat。

　　典型應用電路

　　圖4給(gei)出的(de)是典型的(de)應用電(dian)(dian)路，電(dian)(dian)路中R1, R2由(you)NTC熱敏電(dian)(dian)阻(zu)(zu)值來(lai)確定。設熱敏電(dian)(dian)阻(zu)(zu)在最(zui)低工作溫度時的(de)電(dian)(dian)阻(zu)(zu)為RTL，在最(zui)高(gao)工作溫度時的(de)電(dian)(dian)阻(zu)(zu)為RTH(RTL與RTH的(de)數(shu)據可查電(dian)(dian)池廠方數(shu)據或(huo)做實(shi)驗(yan)得(de)到)，則(ze)R1，R2的(de)阻(zu)(zu)值分別為：

　　圖4：AP5056應用(yong)電路。

　　如果用戶(hu)只關心高溫(wen)保護，而不用關心低溫(wen)保護，則可將R2去掉，只保留R1，這時R1的計算(suan)公式變為：

　　直(zhi)流(liu)適配器與(yu)USB組合的(de)方案

　當充(chong)電(dian)(dian)(dian)(dian)(dian)器需要直流(liu)適配(pei)(pei)器與USB充(chong)電(dian)(dian)(dian)(dian)(dian)兩者都能用時(shi)，可采用圖5所示(shi)的(de)(de)方(fang)案(an)。方(fang)案(an)中，假如使(shi)用USB口進(jin)行供電(dian)(dian)(dian)(dian)(dian)的(de)(de)話，MOS-P門(men)極(ji)接地，USB電(dian)(dian)(dian)(dian)(dian)源(yuan)通(tong)過(guo)MOS-P導通(tong)至VCC，同時(shi)MOS-N處于關斷狀態，PROG上的(de)(de)編程電(dian)(dian)(dian)(dian)(dian)阻(zu)為2K，即充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)設定為500mA，這樣可防止USB接口被(bei)充(chong)電(dian)(dian)(dian)(dian)(dian)器拉(la)死；而當采用5V直流(liu)適配(pei)(pei)器的(de)(de)時(shi)候，適配(pei)(pei)器電(dian)(dian)(dian)(dian)(dian)流(liu)通(tong)過(guo)肖特基二極(ji)管(guan)加至VCC腳，MOS-P由于門(men)極(ji)為高電(dian)(dian)(dian)(dian)(dian)平而被(bei)截止，不會對USB口產生影響。同時(shi)MOS-N由于門(men)極(ji)為高電(dian)(dian)(dian)(dian)(dian)平而導通(tong)，此時(shi)PROG腳上的(de)(de)編程電(dian)(dian)(dian)(dian)(dian)阻(zu)相當于1K(2個(ge)2K電(dian)(dian)(dian)(dian)(dian)阻(zu)并聯(lian))，即設定充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)為1A，來對鋰離子電(dian)(dian)(dian)(dian)(dian)池進(jin)行快速充(chong)電(dian)(dian)(dian)(dian)(dian)。

　　圖(tu)5：交(jiao)流適配器(qi)與USB組合的方案。

　　芯片熱保護功能

　　利用(yong)(yong)晶體管PN結的導通(tong)電(dian)壓隨溫度(du)(du)升(sheng)高(gao)而(er)降低，而(er)其變化值隨溫度(du)(du)的升(sheng)高(gao)而(er)增(zeng)加的特性，AP5056設計了集成于芯片內(nei)部的過(guo)熱(re)保護(hu)功(gong)能(neng)。當(dang)(dang)內(nei)部溫度(du)(du)傳感器升(sheng)至約125℃以上(shang)時，內(nei)部的熱(re)保護(hu)電(dian)路將自動減小充電(dian)電(dian)流的電(dian)流值，隨著溫度(du)(du)的不斷(duan)升(sheng)高(gao)，當(dang)(dang)溫度(du)(du)達到(dao)145℃的時候，則可完(wan)全關閉充電(dian)電(dian)流。該功(gong)能(neng)可以讓用(yong)(yong)戶放心使用(yong)(yong)最(zui)大功(gong)率的充電(dian)電(dian)流而(er)無需擔(dan)心芯片被損壞。

　　充電狀態指示

　　AP5056有CHRG和(he)STDBY兩個狀(zhuang)(zhuang)態(tai)(tai)輸出指示。當(dang)充(chong)電(dian)器處(chu)于充(chong)電(dian)狀(zhuang)(zhuang)態(tai)(tai)時，CHRG置低電(dian)平，STDBY輸出高(gao)阻(zu)態(tai)(tai)；當(dang)電(dian)池處(chu)于充(chong)滿狀(zhuang)(zhuang)態(tai)(tai)時，CHRG變為高(gao)阻(zu)態(tai)(tai)，STDBY被拉為低電(dian)平。

　　如果(guo)不需要用到(dao)狀態指示功能，可(ke)以將不用的相(xiang)應(ying)的狀態輸(shu)出指示腳(jiao)接地。

　　指示燈狀態

　　布板的注意事項

　　AP5056采用(yong)SOP8-PP封裝，芯(xin)片(pian)底部帶有散(san)熱(re)(re)(re)(re)片(pian)，以(yi)(yi)便于將(jiang)(jiang)芯(xin)片(pian)工作時產生的(de)熱(re)(re)(re)(re)量通過散(san)熱(re)(re)(re)(re)片(pian)發散(san)出去，因(yin)此(ci)，為了達到較好的(de)散(san)熱(re)(re)(re)(re)效果(guo)，散(san)熱(re)(re)(re)(re)片(pian)下(xia)的(de)PC板(ban)銅(tong)(tong)箔面積要盡可能的(de)寬闊，并將(jiang)(jiang)之延(yan)伸至(zhi)外(wai)面更(geng)大(da)，更(geng)寬的(de)銅(tong)(tong)箔面積，而且(qie)需(xu)將(jiang)(jiang)散(san)熱(re)(re)(re)(re)片(pian)與散(san), 熱(re)(re)(re)(re)片(pian)下(xia)的(de)銅(tong)(tong)箔用(yong)焊(han)錫(xi)焊(han)接在一(yi)起，以(yi)(yi)增加熱(re)(re)(re)(re)的(de)傳(chuan)導性；此(ci)外(wai)，利用(yong)多個通孔將(jiang)(jiang)上層銅(tong)(tong)箔與下(xia)層銅(tong)(tong)箔連接起來(lai)能夠更(geng)有效地拓(tuo)展散(san)熱(re)(re)(re)(re)面積，有利于將(jiang)(jiang)熱(re)(re)(re)(re)量散(san)至(zhi)周圍環境中(zhong)，增加充電芯(xin)片(pian)的(de)散(san)熱(re)(re)(re)(re)效果(guo)(如圖6所示)。

　　圖(tu)6：AP5056布板示意圖(tu)。

　　在(zai)芯片散熱良(liang)好的(de)情況下，AP5056可提供電路最大充電電流為1600MA，實驗中，在(zai)室溫狀態下，充電電流設置為1600MA，連續工作(zuo)(zuo)15分鐘，IC表(biao)面(mian)溫度為60℃；設置為1000MA時，連續工作(zuo)(zuo)15分鐘，IC表(biao)面(mian)溫度為50℃。

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