在(zai)市場上(shang)，能(neng)量(liang)收(shou)集(ji) IC 剛剛進入最初采用(yong)階段。能(neng)量(liang)收(shou)集(ji) IC 可將適合的(de)換能(neng)器(qi)輸(shu)出轉換成(cheng)電(dian)流，用(yong)于電(dian)池充電(dian)器(qi)設備。盡管(guan)能(neng)量(liang)收(shou)集(ji)自 2000 年初就已經出現了，但(dan)是最近的(de)技術發展才將能(neng)量(liang)收(shou)集(ji)推進到可商(shang)用(yong)的(de)程度。在(zai)能(neng)量(liang)收(shou)集(ji)應用(yong)領域有很(hen)多(duo)機(ji)會，包括：

　　? 在更換電(dian)(dian)池(chi)不(bu)方(fang)便、不(bu)現實或(huo)危險的情況下，取代電(dian)(dian)池(chi)供電(dian)(dian)系統或(huo)給電(dian)(dian)池(chi)供電(dian)(dian)系統再充電(dian)(dian)

　　? 無需導線(xian)來供電或(huo)傳送數據

　　? 用智能無線傳感器(qi)網絡監視和優化(hua)復(fu)雜的(de)工(gong)業過程、安裝在偏遠(yuan)現場的(de)設備、以及大(da)樓的(de)加熱和冷(leng)卻系統(tong)

　　? 從工(gong)業過(guo)程、太陽能電(dian)池板(ban)、內燃機等收集(ji)否(fou)則會浪費掉的熱量

　　? 各種不同的消費電子產品的附屬充電器

　　在這些應用中，有(you)很(hen)多含有(you)固(gu)有(you)的斷(duan)續或低(di)功率電(dian)源(yuan)。而且，有(you)很(hen)多應用將需(xu)要給電(dian)池充電(dian)，以提(ti)供(gong)一個備份電(dian)源(yuan)。

　　并(bing)聯(lian)電(dian)(dian)(dian)壓基(ji)準(zhun)簡單易用，已經出現很(hen)多年(nian)了(le)，有大量產品(pin)。不過，這類(lei)基(ji)準(zhun)不能(neng)(neng)有效(xiao)地(di)給(gei)電(dian)(dian)(dian)池(chi)充電(dian)(dian)(dian)。要配置(zhi)一(yi)(yi)個(ge)并(bing)聯(lian)電(dian)(dian)(dian)壓基(ji)準(zhun)以給(gei)電(dian)(dian)(dian)池(chi)有效(xiao)充電(dian)(dian)(dian)是極端復雜的。此外(wai)，用一(yi)(yi)個(ge)小電(dian)(dian)(dian)流電(dian)(dian)(dian)源或一(yi)(yi)個(ge)斷(duan)續性能(neng)(neng)量收集電(dian)(dian)(dian)源準(zhun)確和安全地(di)給(gei)鋰(li)離子 / 聚合物(wu)、幣形電(dian)(dian)(dian)池(chi)或薄(bo)膜電(dian)(dian)(dian)池(chi)充電(dian)(dian)(dian)，一(yi)(yi)直是難(nan)以實現的。

　　從電(dian)池(chi)(chi)方面來看，盡管(guan)技(ji)術(shu)已經改進了，但是便攜式電(dian)子(zi)設(she)備的(de)電(dian)池(chi)(chi)或(huo)電(dian)池(chi)(chi)組仍然需(xu)要(yao)保(bao)護和查(cha)驗，以(yi)保(bao)持電(dian)池(chi)(chi)在(zai)最(zui)佳狀態運(yun)行。鋰離子(zi) / 聚合物電(dian)池(chi)(chi)技(ji)術(shu)已經成(cheng)(cheng)熟(shu)，是很(hen)多電(dian)子(zi)設(she)備流行的(de)電(dian)源選擇，因為這類電(dian)池(chi)(chi)能(neng)量(liang)(liang)密度高、自(zi)放電(dian)很(hen)少、需(xu)要(yao)很(hen)少的(de)維護、電(dian)壓范圍(wei)很(hen)寬并具(ju)有其他一些特(te)色。幣(bi)形(xing)電(dian)池(chi)(chi)能(neng)量(liang)(liang)密度高、放電(dian)特(te)性(xing)穩(wen)定、重量(liang)(liang)輕且外形(xing)尺寸小。薄膜電(dian)池(chi)(chi)是一種新出現的(de)技(ji)術(shu)，優勢是允許(xu)非(fei)常(chang)多的(de)充電(dian)周期(qi)次數，并具(ju)有物理靈活性(xing)，即視最(zui)終(zhong)應用(yong)的(de)不同(tong)而(er)不同(tong)，薄膜電(dian)池(chi)(chi)可以(yi)做成(cheng)(cheng)幾(ji)乎任何形(xing)狀。不過(guo)，如果不能(neng)正(zheng)確充電(dian)和查(cha)驗，那(nei)么所有這些類型的(de)電(dian)池(chi)(chi)都可能(neng)受到(dao)一些有害(hai)影響。

　　低(di)功(gong)耗(hao)充(chong)電器的設計挑戰

　　可調(diao)并聯(lian)(lian)(lian)基準(zhun)可被設定(ding)以(yi)提供(gong)恰當的(de)電(dian)(dian)池浮置(zhi)電(dian)(dian)壓，但是(shi)這類基準(zhun)缺乏電(dian)(dian)池充電(dian)(dian)器的(de) NTC 功(gong)能(neng)。更重要的(de)是(shi)，所需的(de)工作電(dian)(dian)流太高了，以(yi)至于用(yong)低功(gong)率電(dian)(dian)源(yuan)或(huo)斷續性電(dian)(dian)源(yuan)給電(dian)(dian)池充電(dian)(dian)是(shi)不(bu)現(xian)實(shi)的(de)。或(huo)者(zhe)，可以(yi)用(yong)一(yi)個齊納二(er)極管、一(yi)些電(dian)(dian)阻器、一(yi)個 NPN 晶體管和(he)一(yi)些比較器構成一(yi)個分(fen)立式并聯(lian)(lian)(lian)基準(zhun)，以(yi)提供(gong) NTC 功(gong)能(neng)。不(bu)過(guo)，這樣(yang)的(de)并聯(lian)(lian)(lian)基準(zhun)仍然受到前述限制。此外，分(fen)立式并聯(lian)(lian)(lian)基準(zhun)實(shi)現(xian)起(qi)來(lai)比較復雜，相比之(zhi)下，會占用(yong)更多寶貴(gui)的(de) PCB 面積。

　　典型的電(dian)(dian)池充電(dian)(dian)器 IC 需(xu)要恒定(ding) DC 輸入電(dian)(dian)壓，而且不(bu)能處理能量突(tu)發(fa)。不(bu)過(guo)，諸如(ru)室內(nei)光伏陣列或(huo)壓電(dian)(dian)換能器等斷續性能量收集電(dian)(dian)源提(ti)供的是功(gong)率突(tu)發(fa)。要用這(zhe)類能源給電(dian)(dian)池充電(dian)(dian)，一個靜態工作電(dian)(dian)流低于 1uA 的獨(du)特 IC 是必需(xu)的。

　　鋰離子 / 聚(ju)合(he)物(wu)化(hua)學組成的(de)電(dian)池(chi)(chi)(chi)(chi)提供便攜式電(dian)子設(she)備必(bi)需(xu)的(de)高(gao)性(xing)能(neng)(neng)，但是這類電(dian)池(chi)(chi)(chi)(chi)必(bi)須(xu)小心使用。例如(ru)，如(ru)果用比建議浮置電(dian)壓高(gao) 100mV 的(de)電(dian)壓充電(dian)，鋰離子 / 聚(ju)合(he)物(wu)電(dian)池(chi)(chi)(chi)(chi)可能(neng)(neng)變得不穩(wen)定。此外(wai)，高(gao)壓和高(gao)溫(wen)同時(shi)(shi)存在(zai)會對電(dian)池(chi)(chi)(chi)(chi)壽命產生有害影響，而且(qie)在(zai)極端情況下，可能(neng)(neng)導(dao)致電(dian)池(chi)(chi)(chi)(chi)自毀。就幣形(xing)電(dian)池(chi)(chi)(chi)(chi)和薄(bo)膜電(dian)池(chi)(chi)(chi)(chi)而言，除了高(gao)溫(wen)和高(gao)壓同時(shi)(shi)存在(zai)可能(neng)(neng)產生有害影響，還(huan)有容(rong)量(liang)問(wen)題，因為它(ta)們的(de)外(wai)形(xing)尺(chi)寸很(hen)小。

　　并聯架(jia)構的基本要素和好(hao)處(chu)

　　并聯基準是電(dian)(dian)流(liu)饋送型、兩端子電(dian)(dian)路，在達到目標(biao)電(dian)(dian)壓之前不吸取電(dian)(dian)流(liu)。并聯基準用(yong)起(qi)來像(xiang)一(yi)個齊納二極(ji)(ji)管，而且在電(dian)(dian)路原理圖上(shang)常常顯示為(wei)一(yi)個齊納二極(ji)(ji)管。不過，大(da)多數(shu)并聯基準實際上(shang)都是基于(yu)帶(dai)隙基準電(dian)(dian)壓的。

　　一個并聯基(ji)準(zhun)(zhun)僅需要單(dan)個外(wai)部電阻器來調(diao)節輸(shu)出(chu)電壓(ya)，從(cong)而極其容易使用。沒有最(zui)高輸(shu)入電壓(ya)限制，最(zui)低輸(shu)入電壓(ya)由基(ji)準(zhun)(zhun)電壓(ya)值設定，因為需要一些空間(jian)以正常運行(xing)。

　　此外，并(bing)聯基準在寬(kuan)電流范圍內有(you)良好的(de)(de)穩(wen)(wen)定(ding)性(xing)。很多并(bing)聯基準在有(you)大型或小型容性(xing)負載(zai)時都(dou)是(shi)穩(wen)(wen)定(ding)的(de)(de)。

　　滿足前述電池充電器 IC 設計限(xian)制的任何解決方案都(dou)必須(xu)兼有如下特性(xing)(xing)(xing)：并(bing)聯(lian)穩壓器(qi)的特性(xing)(xing)(xing);能(neng)用低(di)功率(lv)連(lian)續(xu)(xu)或(huo)(huo)斷續(xu)(xu)性(xing)(xing)(xing)電源(yuan)充電的電池充電 IC 的特性(xing)(xing)(xing)。這樣的器(qi)件還(huan)需要保護鋰離(li)子/聚合物(wu)電池、幣形(xing)電池、薄膜(mo)電池或(huo)(huo)電池組的安全，并(bing)使電池或(huo)(huo)電池組達(da)到(dao)最高性(xing)(xing)(xing)能(neng)。

　　凌(ling)力爾特開發了業界第一(yi)款(kuan)(kuan)并(bing)(bing)聯架構(gou)電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)充(chong)(chong)電(dian)(dian)(dian)器(qi)(qi)(qi) LTC4070 和(he) LTC4071，以滿足(zu)這類應(ying)用(yong)(yong)(yong)的(de)(de)(de)(de)(de)需求。LTC4070 是一(yi)款(kuan)(kuan)易用(yong)(yong)(yong)、纖巧(qiao)的(de)(de)(de)(de)(de)并(bing)(bing)聯電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)充(chong)(chong)電(dian)(dian)(dian)器(qi)(qi)(qi)系(xi)統(tong)(tong) IC，適(shi)用(yong)(yong)(yong)于鋰(li)離子(zi) / 聚(ju)合(he)物(wu)(wu)電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)、幣形(xing)電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)或薄(bo)膜電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)。該 IC 的(de)(de)(de)(de)(de)工作電(dian)(dian)(dian)流(liu)為(wei) 450nA，可(ke)保(bao)護電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)，并(bing)(bing)可(ke)用(yong)(yong)(yong)以前不能(neng)使用(yong)(yong)(yong)的(de)(de)(de)(de)(de)非(fei)(fei)常小電(dian)(dian)(dian)流(liu)的(de)(de)(de)(de)(de)斷續性或連(lian)續性充(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)源給這些電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)充(chong)(chong)電(dian)(dian)(dian)。增(zeng)加一(yi)個外部 PMOS 并(bing)(bing)聯器(qi)(qi)(qi)件，LTC4070 的(de)(de)(de)(de)(de)充(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)就(jiu)可(ke)以從 50mA 提高到 500mA。當電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)溫度(du)升(sheng)高時，內部電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)熱量查驗器(qi)(qi)(qi)降(jiang)低浮置(zhi)電(dian)(dian)(dian)壓，以保(bao)護鋰(li)離子(zi) / 聚(ju)合(he)物(wu)(wu)電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)的(de)(de)(de)(de)(de)安(an)全。通過串(chuan)聯配置(zhi)幾(ji)個 LTC4070，可(ke)以給由多節電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)組成的(de)(de)(de)(de)(de)電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)組充(chong)(chong)電(dian)(dian)(dian)，并(bing)(bing)實現各節電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)的(de)(de)(de)(de)(de)容量平(ping)衡。LTC4070 采用(yong)(yong)(yong)扁平(ping) (0.75mm) 8 引線 2mm x 3mm DFN 封裝，僅用(yong)(yong)(yong)單(dan)個外部電(dian)(dian)(dian)阻器(qi)(qi)(qi) (要求與輸入電(dian)(dian)(dian)壓串(chuan)聯) 就(jiu)能(neng)組成一(yi)個完(wan)整(zheng)和(he)超緊(jin)湊(cou)的(de)(de)(de)(de)(de)充(chong)(chong)電(dian)(dian)(dian)器(qi)(qi)(qi)解決方案(an)。該器(qi)(qi)(qi)件的(de)(de)(de)(de)(de)功能(neng)集使其非(fei)(fei)常適(shi)用(yong)(yong)(yong)于連(lian)續性和(he)斷續性低功率充(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)源應(ying)用(yong)(yong)(yong)，包(bao)括鋰(li)離子(zi) / 聚(ju)合(he)物(wu)(wu)電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)備份、薄(bo)膜電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)、幣形(xing)電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)、存儲器(qi)(qi)(qi)備份、太陽能(neng)供電(dian)(dian)(dian)系(xi)統(tong)(tong)、嵌入式(shi)汽車和(he)能(neng)量收集。

　　LTC4070提供(gong)引腳(jiao)可(ke)選的(de) 4.0V、4.1V 和 4.2V 設置(zhi)，其(qi)準(zhun)確度為 1% 的(de)電池(chi)浮置(zhi)電壓允許用戶在電池(chi)能(neng)量(liang)密度和壽(shou)命(ming)之間進行(xing)取舍(she)。獨立(li)的(de)低電池(chi)電量(liang)和高(gao)電池(chi)電量(liang)監(jian)察(cha)狀態輸出(chu)(chu)指(zhi)示放電或完全充電的(de)電池(chi)。再加上(shang)一個與負載串聯的(de)外部 P-FET，該低電池(chi)電量(liang)狀態輸出(chu)(chu)可(ke)實現鎖(suo)斷功能(neng)，該功能(neng)自動斷接(jie)系統負載和電池(chi)，以防止電池(chi)深度放電。

　　除了緊(jin)湊的 2mm x 3mm 8 引(yin)線 DFN 封裝，LTC4070 還采用(yong) 8 引(yin)線 MSOP。這些(xie)器件規定在 -40?C 至 125?C 的溫度(du)范圍內工作。

　　通過(guo)防(fang)止電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)超過(guo)設(she)定水平(ping)，LTC4070 提供了(le)一個(ge)簡單(dan)、可(ke)靠(kao)、高(gao)性能的電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)保(bao)護和(he)充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)解決(jue)方(fang)案。其并聯(lian)架構在輸入電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源和(he)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)之間(jian)僅需(xu)要一個(ge)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻器(qi)，就可(ke)應對多(duo)種電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)應用。當輸入電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源去掉，且電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)低(di)于高(gao)的電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)輸出門限時，LTC4070 僅從電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)吸(xi)取 450nA 電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)。

　　當電(dian)池電(dian)壓(ya)低(di)于設定的浮置(zhi)電(dian)壓(ya)時，充(chong)電(dian)速率由輸入電(dian)壓(ya)、電(dian)池電(dian)壓(ya)和輸入電(dian)阻器決定：

　　ICHG = (VIN ? VBAT) / RIN

　　當電(dian)池電(dian)壓接近浮置電(dian)壓時，LTC4070 從(cong)電(dian)池分(fen)走(zou)一部分(fen)電(dian)流(liu)(liu)，從(cong)而(er)降低了(le)充電(dian)電(dian)流(liu)(liu)。在(zai)整(zheng)個溫(wen)度(du)范圍內(nei)變化浮置電(dian)壓的準確(que)度(du)為 ±1% 時，LTC4070 可以分(fen)走(zou)高達 50mA 的電(dian)流(liu)(liu)。分(fen)流(liu)(liu)限(xian)制了(le)最大充電(dian)電(dian)流(liu)(liu)，不過(guo)通(tong)過(guo)增加(jia)一個外(wai)部 P 溝(gou)道(dao) MOSFET，50mA 的內(nei)部分(fen)流(liu)(liu)能力還可以提(ti)高，參見圖 1。

　　在內部(bu)，LTC4070 采用了(le)一個由(you)放大(da)器 EA (參見圖 2) 驅動的 P 溝(gou)道 MOSFET。VCC 和 GND 之間的電壓(ya)達到 VF (即并(bing)聯(lian)電壓(ya)) 之前，流(liu)(liu)(liu)經(jing)該器件(jian)的電流(liu)(liu)(liu)為零。VF 可以(yi)由(you) ADJ 和 NTC 改變，但始終在 3.8V 到 4.2V 之間。如果(guo) VCC 電壓(ya)低于這個值，那么(me) PFET 中的電流(liu)(liu)(liu)為零。如果(guo) VCC電壓(ya)試圖上(shang)升(sheng)(sheng)到超(chao)過 VF，那么(me)電流(liu)(liu)(liu)將流(liu)(liu)(liu)過該器件(jian)，以(yi)防止電壓(ya)上(shang)升(sheng)(sheng)，這就是分流(liu)(liu)(liu)。

　　工作電(dian)(dian)(dian)(dian)流是給該芯片中其余所有電(dian)(dian)(dian)(dian)路供電(dian)(dian)(dian)(dian)所需的(de)電(dian)(dian)(dian)(dian)流。如果(guo)不存在外(wai)部電(dian)(dian)(dian)(dian)源，那么這就是從電(dian)(dian)(dian)(dian)池吸(xi)取(qu)的(de)電(dian)(dian)(dian)(dian)流。

　　當(dang)電(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)壓(ya)低時(shi)，更多的電(dian)(dian)(dian)(dian)壓(ya)加在輸入(ru)電(dian)(dian)(dian)(dian)阻(zu)器兩端，因此進入(ru)電(dian)(dian)(dian)(dian)池的電(dian)(dian)(dian)(dian)流 (即充(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流) 略大于電(dian)(dian)(dian)(dian)池完全(quan)充(chong)電(dian)(dian)(dian)(dian)時(shi)的電(dian)(dian)(dian)(dian)流。當(dang)電(dian)(dian)(dian)(dian)池充(chong)滿電(dian)(dian)(dian)(dian)時(shi)，將沒有電(dian)(dian)(dian)(dian)流進入(ru)電(dian)(dian)(dian)(dian)池，所有的輸入(ru)電(dian)(dian)(dian)(dian)流都將進入(ru)分流器。

　　工作電(dian)流(liu)很重(zhong)要，因為(wei)它(ta)給(gei)“實際”輸(shu)入(ru)(ru)電(dian)源(yuan)的(de)電(dian)流(liu)能(neng)(neng)(neng)力(li)(li)設定了(le)一個(ge)低(di)限制。顯然，一個(ge)僅有(you)(you) 100nA驅動(dong)能(neng)(neng)(neng)力(li)(li)的(de)輸(shu)入(ru)(ru)電(dian)源(yuan)不可(ke)能(neng)(neng)(neng)給(gei)采(cai)用 LTC4070 的(de)電(dian)池充(chong)電(dian)。不過，如(ru)果有(you)(you) 1uA 的(de)驅動(dong)能(neng)(neng)(neng)力(li)(li)，就(jiu)能(neng)(neng)(neng)剩下少量電(dian)流(liu)去充(chong)電(dian)。如(ru)果能(neng)(neng)(neng)得到 10uA 的(de)驅動(dong)能(neng)(neng)(neng)力(li)(li)，那(nei)么(me)該電(dian)流(liu) 90% 以(yi)上都(dou)可(ke)用于充(chong)電(dian)。

　　NTC 電池查驗電路(lu)保護電池

　　LTC4070 用一個通過(guo)(guo)熱(re)量耦合到(dao)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)的負(fu)溫(wen)(wen)度(du)(du)系數(shu)熱(re)敏電(dian)(dian)(dian)(dian)(dian)阻測量電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)溫(wen)(wen)度(du)(du)。NTC 熱(re)敏電(dian)(dian)(dian)(dian)(dian)阻的溫(wen)(wen)度(du)(du)特性在電(dian)(dian)(dian)(dian)(dian)阻-溫(wen)(wen)度(du)(du)轉換表(biao)中規(gui)定。在溫(wen)(wen)度(du)(du)高于 40°C 以(yi)后，每上升 10°C，內部(bu) NTC 電(dian)(dian)(dian)(dian)(dian)路就(jiu)降低一次浮置電(dian)(dian)(dian)(dian)(dian)壓，以(yi)防止(zhi)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)過(guo)(guo)熱(re) (參見圖 3 以(yi)了解詳細信(xin)息)。

　　LTC4070 采用一個(ge)(ge)電(dian)阻值之(zhi)比來(lai)(lai)測量(liang)電(dian)池溫度。LTC4070 在 NTCBIAS 與(yu) GND 引腳(jiao)之(zhi)間布設了一個(ge)(ge)具 4 個(ge)(ge)抽(chou)頭(tou)的內部固定(ding)電(dian)阻分壓器。定(ding)期地(di)將這(zhe)些抽(chou)頭(tou)上的電(dian)壓與(yu) NTC 引腳(jiao)上的電(dian)壓進行比較，以測量(liang)電(dian)池溫度。為(wei)了節省功率，通過以大約每 1.5s 一次的頻度把 NTCBIAS 引腳(jiao)偏(pian)置至 VCC 來(lai)(lai)定(ding)期測量(liang)電(dian)池溫度。

    LTC4070 具(ju)有一(yi)個(ge)(ge)與 ADJ 引(yin)(yin)腳(jiao)相(xiang)連(lian)的(de)內置(zhi)(zhi)三態解碼(ma)器(qi)，用(yong)以(yi)提(ti)供(gong) 3 種可編程(cheng)浮置(zhi)(zhi)電(dian)(dian)(dian)壓(ya)(ya)：4.0V、4.1V、或 4.2V。當(dang) ADJ 引(yin)(yin)腳(jiao)連(lian)接(jie)至 GND、浮置(zhi)(zhi)或連(lian)接(jie)至 VCC 時，浮置(zhi)(zhi)電(dian)(dian)(dian)壓(ya)(ya)將被(bei)分別設置(zhi)(zhi)為 4.0V、4.1V 或 4.2V。大(da)約每 1.5s 對(dui) ADJ 引(yin)(yin)腳(jiao)的(de)狀態進行一(yi)次(ci)采樣。當(dang) ADJ 引(yin)(yin)腳(jiao)被(bei)采樣時，LTC4070 在其(qi)上(shang)施加一(yi)個(ge)(ge)相(xiang)對(dui)較低的(de)阻(zu)抗電(dian)(dian)(dian)壓(ya)(ya)。這種做法可以(yi)防(fang)止低水平的(de)電(dian)(dian)(dian)路板漏電(dian)(dian)(dian)流破壞設定的(de)浮置(zhi)(zhi)電(dian)(dian)(dian)壓(ya)(ya)。免(mian)除電(dian)(dian)(dian)阻(zu)器(qi)不僅縮減(jian)了解決方案(an)的(de)外形尺寸(cun)，而且(qie)還(huan)由于無(wu)需(xu)使用(yong)大(da)阻(zu)值的(de)電(dian)(dian)(dian)阻(zu)器(qi)而降低了靜態電(dian)(dian)(dian)流。

　　另外，該器(qi)件還具有(you)狀態輸(shu)(shu)出(chu)(chu)及發(fa)送指(zhi)示信號的(de)能力。高(gao)(gao)電(dian)(dian)(dian)池電(dian)(dian)(dian)量監(jian)(jian)視器(qi)輸(shu)(shu)出(chu)(chu) (HBO) 是一個高(gao)(gao)態有(you)效 CMOS 輸(shu)(shu)出(chu)(chu)，當(dang)電(dian)(dian)(dian)池充滿電(dian)(dian)(dian)且電(dian)(dian)(dian)流通過(guo)分路(lu)離開 BAT 時，該輸(shu)(shu)出(chu)(chu)將(jiang)發(fa)出(chu)(chu)指(zhi)示信號。低(di)電(dian)(dian)(dian)池電(dian)(dian)(dian)量監(jian)(jian)視器(qi)輸(shu)(shu)出(chu)(chu) (LBO) 也是一個高(gao)(gao)態有(you)效 CMOS 輸(shu)(shu)出(chu)(chu)，當(dang)電(dian)(dian)(dian)池放電(dian)(dian)(dian)至 3.2V 以(yi)(yi)下時，此輸(shu)(shu)出(chu)(chu)將(jiang)發(fa)出(chu)(chu)對應的(de)指(zhi)示信號。最后，外部(bu)驅動器(qi)輸(shu)(shu)出(chu)(chu)引腳 DRV 可(ke)連接至外部(bu) P-FET 的(de)柵(zha)極以(yi)(yi)增(zeng)加分路(lu)電(dian)(dian)(dian)流，從(cong)而(er)滿足那些需(xu)要 50mA 以(yi)(yi)上(shang)充電(dian)(dian)(dian)電(dian)(dian)(dian)流 (最大(da) 500mA) 的(de)應用(yong)。

　　LTC4071 集成電池組保(bao)護功能

　　LTC4071 也是(shi)一(yi)個(ge)并聯電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)器系統，而且還是(shi)首款具(ju)有(you)集成型(xing)(xing)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)組保護功(gong)(gong)能(neng)(neng) (包括低(di)(di)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)量斷(duan)(duan)接(jie)(jie)(jie)) 的(de)器件。相(xiang)(xiang)比于(yu)(yu) LTC4070，LTC4071 的(de)不同之處包括：其擁有(you)集成型(xing)(xing)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)組保護功(gong)(gong)能(neng)(neng) (低(di)(di)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)量斷(duan)(duan)接(jie)(jie)(jie)) 、但(dan)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)能(neng)(neng)力較低(di)(di) (50mA)、靜態(tai)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)較高 (550nA) 、且不具(ju)備 LBO。對于(yu)(yu)避免低(di)(di)電(dian)(dian)(dian)(dian)(dian)(dian)量電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)由(you)于(yu)(yu)自放電(dian)(dian)(dian)(dian)(dian)(dian)而受損而言，低(di)(di)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)量斷(duan)(duan)接(jie)(jie)(jie)是(shi)一(yi)種必需的(de)關鍵性功(gong)(gong)能(neng)(neng)。雖然 LTC4070 能(neng)(neng)夠利(li)用(yong) LBO 和(he)一(yi)個(ge)外(wai)部(bu) P-FET 來實現低(di)(di)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)量斷(duan)(duan)接(jie)(jie)(jie)功(gong)(gong)能(neng)(neng)，但(dan)該(gai) IC 仍將(jiang)繼續從(cong)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)消耗全部(bu) IQ (約(yue) 0.5μA)。即(ji)使是(shi)如此之小(xiao)的(de)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)漏電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)也會在(zai)(zai)一(yi)夜之間導致(zhi)低(di)(di)電(dian)(dian)(dian)(dian)(dian)(dian)量電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)的(de)損壞(huai)。相(xiang)(xiang)反，LTC4071 集成了一(yi)個(ge)徹底的(de)低(di)(di)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)量斷(duan)(duan)接(jie)(jie)(jie)功(gong)(gong)能(neng)(neng)，當(dang)斷(duan)(duan)接(jie)(jie)(jie)時(shi)，從(cong)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)吸取的(de)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)接(jie)(jie)(jie)近(jin)零 (在(zai)(zai)室溫時(shi) <1nA，在(zai)(zai) 125°C 時(shi) < 25nA)。為(wei)(wei)了在(zai)(zai) LTC4071 中提供(gong)這一(yi)功(gong)(gong)能(neng)(neng)，相(xiang)(xiang)應于(yu)(yu) LTC4070 的(de) LBO 和(he) DRV 引腳被去(qu)掉了。參見圖(tu) 4 以了解詳細(xi)信息(xi)。這使 LTC4071 的(de)最大分流(liu)(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)固定為(wei)(wei) 50mA (LTC4070 是(shi) 50mA，但(dan)采用(yong)一(yi)個(ge)外(wai)部(bu) FET，就能(neng)(neng)達到(dao) 500mA)，而且將(jiang)該(gai) IC 的(de)靜態(tai)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)提高到(dao)了 550nA (LTC4070 的(de)靜態(tai)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)為(wei)(wei) 450nA)。下(xia)表 1 總結了這兩個(ge)相(xiang)(xiang)互關聯的(de) IC 之間的(de)差別。

　　結論

　　并(bing)聯(lian)基(ji)準有(you)(you)很(hen)多應(ying)(ying)用，而(er)且視其功(gong)能(neng)(neng)的(de)(de)(de)不同而(er)不同，并(bing)聯(lian)基(ji)準甚(shen)至可(ke)以用來給(gei)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)充(chong)電(dian)(dian)(dian)(dian)。不過，這種類(lei)型(xing)的(de)(de)(de)應(ying)(ying)用有(you)(you)很(hen)多缺點，包(bao)括(kuo)大靜態電(dian)(dian)(dian)(dian)流和缺乏(fa)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)保護功(gong)能(neng)(neng)。現在，有(you)(you)了合(he)適(shi)的(de)(de)(de) DC-DC 轉(zhuan)換器(qi)(qi)或電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)充(chong)電(dian)(dian)(dian)(dian)器(qi)(qi)，因此(ci)可(ke)以對低功(gong)率能(neng)(neng)量收集(ji)應(ying)(ying)用進行查驗了。凌力爾特公(gong)司(si)開(kai)發了 LTC4070 和 LTC4071 并(bing)聯(lian)充(chong)電(dian)(dian)(dian)(dian)器(qi)(qi)系統(tong)，這兩款器(qi)(qi)件適(shi)用于鋰離子(zi) / 聚合(he)物電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)、幣形電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)、薄膜電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)和電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)組，可(ke)為具有(you)(you)低功(gong)率電(dian)(dian)(dian)(dian)源的(de)(de)(de)領先應(ying)(ying)用提供(gong)一(yi)種簡單、有(you)(you)效的(de)(de)(de)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)充(chong)電(dian)(dian)(dian)(dian)和電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)組保護解決方案。