電(dian)(dian)電(dian)(dian)流(liu)大(da)(da)于(yu)電(dian)(dian)池(chi)容(rong)量(liang)(liang)的(de)(de)(de)20 隨著當今(jin)數碼電(dian)(dian)子(zi)產品功能(neng)的(de)(de)(de)不斷增(zeng)加，LCD屏幕越(yue)來(lai)越(yue)大(da)(da)，以及不斷增(zeng)強(qiang)的(de)(de)(de)多媒體視屏功能(neng)，市面上(shang)鋰離(li)子(zi)/聚(ju)合物電(dian)(dian)池(chi)的(de)(de)(de)容(rong)量(liang)(liang)也做得越(yue)來(lai)越(yue)大(da)(da)。與此同時(shi)，消(xiao)費者對(dui)(dui)縮短大(da)(da)容(rong)量(liang)(liang)電(dian)(dian)池(chi)的(de)(de)(de)充(chong)電(dian)(dian)時(shi)間(jian)提出了(le)期(qi)望(wang)。為了(le)能(neng)更快速(su)有(you)效地對(dui)(dui)這(zhe)些大(da)(da)容(rong)量(liang)(liang)電(dian)(dian)池(chi)進行(xing)充(chong)電(dian)(dian)，以滿足消(xiao)費者不斷增(zeng)長的(de)(de)(de)需求(qiu)，無錫(xi)芯朋微電(dian)(dian)子(zi)推出了(le)大(da)(da)電(dian)(dian)流(liu)鋰離(li)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)鋰離子或(huo)(huo)鋰聚合物(wu)可(ke)充(chong)電電池(chi)進行恒流/恒壓充(chong)電的(de)充(chong)電器電路。器件(jian)內部(bu)采用PMOSFET架構(gou)，應用時不(bu)需要外部(bu)另加阻流二極管(guan)。熱(re)反饋電路可(ke)以(yi)自動調(diao)節(jie)充(chong)電電流，使(shi)器件(jian)在功耗(hao)比較(jiao)大(da)或(huo)(huo)者(zhe)環(huan)境溫度(du)(du)比較(jiao)高的(de)情況(kuang)下將芯(xin)片溫度(du)(du)控制(zhi)在安全范圍(wei)內。

　　AP5056只需要極少(shao)的外圍元器件(jian)，可(ke)以適(shi)應USB 電(dian)(dian)(dian)(dian)源(yuan)和(he)適(shi)配器電(dian)(dian)(dian)(dian)源(yuan)工作，非常適(shi)用(yong)于便攜式應用(yong)的領域。充電(dian)(dian)(dian)(dian)輸出電(dian)(dian)(dian)(dian)壓(ya)為4.2V，充電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流的大小可(ke)以通過一個外部電(dian)(dian)(dian)(dian)阻設置(zhi)。在(zai)恒壓(ya)充電(dian)(dian)(dian)(dian)階段中，當充電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流降至設定值1/10 時，AP5056將終止(zhi)充電(dian)(dian)(dian)(dian)循環。

　　當輸(shu)(shu)入電(dian)(dian)(dian)壓(交流適配器或者USB電(dian)(dian)(dian)源)掉電(dian)(dian)(dian)時(shi)(shi)，AP5056自(zi)動進入低功(gong)耗的睡眠模式，此(ci)時(shi)(shi)電(dian)(dian)(dian)池(chi)的電(dian)(dian)(dian)流消耗小于2微(wei)安。其它功(gong)能(neng)(neng)包括輸(shu)(shu)入電(dian)(dian)(dian)壓過低鎖(suo)存、芯片(pian)使能(neng)(neng)輸(shu)(shu)入、自(zi)動再充電(dian)(dian)(dian)、電(dian)(dian)(dian)池(chi)溫度監(jian)控以(yi)及狀態指示等功(gong)能(neng)(neng)。

　　充(chong)電(dian)過(guo)程：AP5056在整個電(dian)池充(chong)電(dian)過(guo)程中有(you)四種基本充(chong)電(dian)模式(shi)：涓(juan)流充(chong)電(dian)、恒流充(chong)電(dian)、恒壓充(chong)電(dian)和充(chong)電(dian)完(wan)成與再充(chong)電(dian)。

　　涓(juan)(juan)流充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)：充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)開(kai)始前，AP5056先(xian)檢查輸入(ru)(ru)(ru)電(dian)(dian)(dian)(dian)(dian)(dian)源，當輸入(ru)(ru)(ru)電(dian)(dian)(dian)(dian)(dian)(dian)源大于最(zui)小工作電(dian)(dian)(dian)(dian)(dian)(dian)壓或(huo)欠壓鎖定(ding)閾值，并且芯片使(shi)能端(duan)接(jie)高(gao)(gao)電(dian)(dian)(dian)(dian)(dian)(dian)平(ping)時(shi)，AP5056開(kai)始對(dui)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)。AP5056先(xian)檢查電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的(de)狀態。如果(guo)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)(dian)壓高(gao)(gao)于3V，充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)器則進入(ru)(ru)(ru)恒流充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)；而如果(guo)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)(dian)壓低于3V時(shi)，充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)器則進入(ru)(ru)(ru)涓(juan)(juan)流充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)模式(shi)。涓(juan)(juan)流充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流是恒流充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流的(de)十分之(zhi)(zhi)一(還是以(yi)恒定(ding)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流為(wei)1A舉例，則涓(juan)(juan)流充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流為(wei)100mA)，涓(juan)(juan)流充(chong)(chong)(chong)電(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)池(chi)電(dian)(dian)(dian)(dian)(dian)(dian)壓達到(dao)3V后結束，之(zhi)(zhi)后進入(ru)(ru)(ru)恒流充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)階段。

　　圖(tu)2：AP5056封(feng)裝。

　　恒(heng)流充電(dian)：恒(heng)流充電(dian)模式中(zhong)，充電(dian)電(dian)流由PROG腳與(yu)GND間的電(dian)阻RPROG確定(ding)。(參見下文“可(ke)編程的充電(dian)電(dian)流”)

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

　　AP5056進(jin)入(ru)恒(heng)流充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)模(mo)式(shi)中后(hou)，將(jiang)一直(zhi)按設定的(de)電(dian)(dian)(dian)(dian)(dian)(dian)流值(zhi)保持充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)，直(zhi)到(dao)電(dian)(dian)(dian)(dian)(dian)(dian)池慢(man)(man)慢(man)(man)到(dao)達電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)調(diao)節點(dian)4.2V，轉而(er)進(jin)入(ru)恒(heng)壓(ya)(ya)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)。恒(heng)壓(ya)(ya)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)：在(zai)(zai)電(dian)(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)慢(man)(man)慢(man)(man)接近4.2V時，充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)器(qi)(qi)就漸(jian)(jian)漸(jian)(jian)轉為恒(heng)壓(ya)(ya)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)。此時原先的(de)恒(heng)流充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流也(ye)慢(man)(man)慢(man)(man)減(jian)小，并隨著電(dian)(dian)(dian)(dian)(dian)(dian)池容量越來越接近最大容量而(er)急劇下(xia)降。 充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)完(wan)成與再充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)：當充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流被探(tan)測到(dao)減(jian)小至恒(heng)流充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流的(de)10%后(hou)，充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)器(qi)(qi)終止向(xiang)(xiang)電(dian)(dian)(dian)(dian)(dian)(dian)池充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)，進(jin)入(ru)低功耗的(de)待機模(mo)式(shi)。 在(zai)(zai)待機模(mo)式(shi)下(xia)，AP5056會繼續檢測電(dian)(dian)(dian)(dian)(dian)(dian)池端的(de)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)，如(ru)果電(dian)(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)降到(dao)4.05V以下(xia)，則充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)器(qi)(qi)將(jiang)再次(ci)向(xiang)(xiang)電(dian)(dian)(dian)(dian)(dian)(dian)池充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)。

　　可編程的(de)充電(dian)電(dian)流(liu)：AP5056的(de)充電(dian)電(dian)流(liu)由連接在PROG腳與GND之間RPROG電(dian)阻來確(que)定，計算公式(shi)如下：

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

　　例(li)如，客戶需要得(de)到(dao)一個1A的充電電流的話，根據公式得(de)到(dao)

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

　　圖3顯示了(le)RPROG為1K和2K時，不同(tong)的(de)電(dian)(dian)源輸入Vcc 與充電(dian)(dian)電(dian)(dian)流(liu)Ibat之間的(de)關(guan)系圖，可以看到充電(dian)(dian)輸出電(dian)(dian)流(liu)基本沒有很大變化，只與RPROG的(de)設(she)定值有關(guan)系。

　　圖3：電源輸入(ru)Vcc VS 充(chong)電電流Ibat。

　　典型應用電路

　　圖4給出的是典型的應用電(dian)路(lu)，電(dian)路(lu)中R1, R2由NTC熱敏(min)電(dian)阻(zu)(zu)值(zhi)來確定。設熱敏(min)電(dian)阻(zu)(zu)在最(zui)低(di)工(gong)作(zuo)溫(wen)度時的電(dian)阻(zu)(zu)為RTL，在最(zui)高工(gong)作(zuo)溫(wen)度時的電(dian)阻(zu)(zu)為RTH(RTL與RTH的數(shu)據可查電(dian)池廠方數(shu)據或做實驗得到)，則R1，R2的阻(zu)(zu)值(zhi)分別(bie)為：

　　圖4：AP5056應用電路。

　　如果(guo)用戶只關心(xin)(xin)高(gao)溫保護(hu)，而不用關心(xin)(xin)低(di)溫保護(hu)，則(ze)可(ke)將R2去掉(diao)，只保留(liu)R1，這時R1的計算公式變為(wei)：

　　直流(liu)適配器與(yu)USB組合的方案

　當(dang)充電(dian)(dian)(dian)(dian)器(qi)需要直流適(shi)配器(qi)與USB充電(dian)(dian)(dian)(dian)兩者都(dou)能(neng)用時，可(ke)采用圖5所示(shi)的(de)方案。方案中，假如使用USB口進行(xing)供電(dian)(dian)(dian)(dian)的(de)話，MOS-P門(men)(men)極(ji)接地(di)，USB電(dian)(dian)(dian)(dian)源通過(guo)MOS-P導通至(zhi)VCC，同時MOS-N處于關斷狀態，PROG上的(de)編(bian)程電(dian)(dian)(dian)(dian)阻為2K，即(ji)(ji)充電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流設(she)定為500mA，這樣可(ke)防(fang)止USB接口被(bei)(bei)充電(dian)(dian)(dian)(dian)器(qi)拉死；而(er)當(dang)采用5V直流適(shi)配器(qi)的(de)時候(hou)，適(shi)配器(qi)電(dian)(dian)(dian)(dian)流通過(guo)肖(xiao)特基二(er)極(ji)管(guan)加至(zhi)VCC腳(jiao)，MOS-P由(you)于門(men)(men)極(ji)為高(gao)電(dian)(dian)(dian)(dian)平而(er)被(bei)(bei)截止，不會(hui)對(dui)USB口產生影響。同時MOS-N由(you)于門(men)(men)極(ji)為高(gao)電(dian)(dian)(dian)(dian)平而(er)導通，此時PROG腳(jiao)上的(de)編(bian)程電(dian)(dian)(dian)(dian)阻相(xiang)當(dang)于1K(2個2K電(dian)(dian)(dian)(dian)阻并聯)，即(ji)(ji)設(she)定充電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流為1A，來對(dui)鋰離子電(dian)(dian)(dian)(dian)池進行(xing)快速充電(dian)(dian)(dian)(dian)。

　　圖5：交流適(shi)配器與USB組合的方案。

　　芯片熱保護功能

　　利用晶體管PN結的(de)(de)導通電(dian)壓隨溫(wen)度(du)升高(gao)而降低，而其變化(hua)值隨溫(wen)度(du)的(de)(de)升高(gao)而增加的(de)(de)特(te)性，AP5056設計了集成于芯片(pian)(pian)內(nei)部(bu)的(de)(de)過熱(re)保護(hu)功(gong)能。當內(nei)部(bu)溫(wen)度(du)傳(chuan)感(gan)器升至(zhi)約125℃以上(shang)時，內(nei)部(bu)的(de)(de)熱(re)保護(hu)電(dian)路(lu)將自(zi)動(dong)減小(xiao)充電(dian)電(dian)流的(de)(de)電(dian)流值，隨著溫(wen)度(du)的(de)(de)不斷(duan)升高(gao)，當溫(wen)度(du)達到145℃的(de)(de)時候，則可完全關閉充電(dian)電(dian)流。該(gai)功(gong)能可以讓用戶放心使用最大功(gong)率的(de)(de)充電(dian)電(dian)流而無需(xu)擔心芯片(pian)(pian)被損壞。

　　充電狀態指示

　　AP5056有CHRG和STDBY兩個(ge)狀(zhuang)態輸出(chu)指(zhi)示。當充電器(qi)處(chu)于(yu)充電狀(zhuang)態時，CHRG置低電平，STDBY輸出(chu)高(gao)(gao)阻態；當電池處(chu)于(yu)充滿(man)狀(zhuang)態時，CHRG變為(wei)(wei)高(gao)(gao)阻態，STDBY被拉(la)為(wei)(wei)低電平。

　　如果不(bu)需要用(yong)到狀態(tai)(tai)指(zhi)示功(gong)能，可以將(jiang)不(bu)用(yong)的相應(ying)的狀態(tai)(tai)輸出指(zhi)示腳(jiao)接地。

　　指示燈狀態

　　布板的注意事項

　　AP5056采用(yong)(yong)SOP8-PP封裝，芯(xin)片(pian)(pian)底部帶有散(san)熱(re)(re)片(pian)(pian)，以便(bian)于將(jiang)(jiang)芯(xin)片(pian)(pian)工作時產(chan)生的(de)(de)(de)熱(re)(re)量(liang)通過散(san)熱(re)(re)片(pian)(pian)發(fa)散(san)出(chu)去，因此，為(wei)了達到較好的(de)(de)(de)散(san)熱(re)(re)效(xiao)果，散(san)熱(re)(re)片(pian)(pian)下的(de)(de)(de)PC板銅箔(bo)(bo)面(mian)(mian)積要盡可能(neng)的(de)(de)(de)寬(kuan)闊，并將(jiang)(jiang)之延伸至外面(mian)(mian)更(geng)大，更(geng)寬(kuan)的(de)(de)(de)銅箔(bo)(bo)面(mian)(mian)積，而(er)且(qie)需(xu)將(jiang)(jiang)散(san)熱(re)(re)片(pian)(pian)與散(san), 熱(re)(re)片(pian)(pian)下的(de)(de)(de)銅箔(bo)(bo)用(yong)(yong)焊(han)錫焊(han)接(jie)在一起，以增加熱(re)(re)的(de)(de)(de)傳導性；此外，利用(yong)(yong)多個通孔將(jiang)(jiang)上層銅箔(bo)(bo)與下層銅箔(bo)(bo)連接(jie)起來能(neng)夠更(geng)有效(xiao)地(di)拓展散(san)熱(re)(re)面(mian)(mian)積，有利于將(jiang)(jiang)熱(re)(re)量(liang)散(san)至周圍環境中，增加充電(dian)芯(xin)片(pian)(pian)的(de)(de)(de)散(san)熱(re)(re)效(xiao)果(如圖(tu)6所示)。

　　圖(tu)(tu)6：AP5056布板(ban)示意圖(tu)(tu)。

　　在芯片散熱(re)良好的(de)情況下(xia)，AP5056可提供電(dian)路最大(da)充電(dian)電(dian)流(liu)為(wei)(wei)(wei)1600MA，實驗中(zhong)，在室溫(wen)(wen)狀(zhuang)態下(xia)，充電(dian)電(dian)流(liu)設置(zhi)為(wei)(wei)(wei)1600MA，連續工作15分鐘(zhong)，IC表面(mian)溫(wen)(wen)度為(wei)(wei)(wei)60℃；設置(zhi)為(wei)(wei)(wei)1000MA時(shi)，連續工作15分鐘(zhong)，IC表面(mian)溫(wen)(wen)度為(wei)(wei)(wei)50℃。

％時：
充(chong)電(dian)時(shi)間（小(xiao)時(shi)）＝電(dian)池容量（mAH）×1.1÷充(chong)電(dian)電(dian)流(liu)(mA)