在(zai)市場(chang)上，能(neng)(neng)量(liang)收(shou)集(ji) IC 剛剛進入最初(chu)采用(yong)階段(duan)。能(neng)(neng)量(liang)收(shou)集(ji) IC 可將適(shi)合的(de)換能(neng)(neng)器輸出(chu)轉(zhuan)換成電流，用(yong)于電池充電器設備。盡(jin)管能(neng)(neng)量(liang)收(shou)集(ji)自 2000 年初(chu)就已經出(chu)現了，但是最近(jin)的(de)技術發(fa)展(zhan)才將能(neng)(neng)量(liang)收(shou)集(ji)推進到(dao)可商用(yong)的(de)程度。在(zai)能(neng)(neng)量(liang)收(shou)集(ji)應用(yong)領域(yu)有很多機會，包括(kuo)：

　　? 在更換電(dian)(dian)池(chi)不方便、不現實或危險的情況下，取(qu)代(dai)電(dian)(dian)池(chi)供電(dian)(dian)系統或給(gei)電(dian)(dian)池(chi)供電(dian)(dian)系統再充電(dian)(dian)

　　? 無需(xu)導線(xian)來供電或傳送(song)數據

　　? 用智能無線傳感器網絡監(jian)視(shi)和優化復雜的(de)工業過程、安(an)裝在(zai)偏遠(yuan)現場的(de)設備(bei)、以及大樓的(de)加熱和冷(leng)卻(que)系統

　　? 從(cong)工業過(guo)程、太(tai)陽能電(dian)池板、內燃機等(deng)收集否則會(hui)浪(lang)費掉的熱量

　　? 各種不同的消費電子產品的附屬充電器

　　在(zai)這些應(ying)用中，有(you)(you)很多含有(you)(you)固有(you)(you)的斷續或低功(gong)率電(dian)源。而(er)且(qie)，有(you)(you)很多應(ying)用將(jiang)需要(yao)給電(dian)池充電(dian)，以(yi)提供一個備份電(dian)源。

　　并(bing)聯(lian)電(dian)壓(ya)基(ji)(ji)(ji)準(zhun)(zhun)簡單易用，已經出(chu)現很多年了，有大(da)量產(chan)品。不(bu)過，這類(lei)基(ji)(ji)(ji)準(zhun)(zhun)不(bu)能(neng)有效地給(gei)電(dian)池充電(dian)。要配(pei)置一(yi)個(ge)(ge)并(bing)聯(lian)電(dian)壓(ya)基(ji)(ji)(ji)準(zhun)(zhun)以給(gei)電(dian)池有效充電(dian)是極(ji)端復雜的(de)。此外，用一(yi)個(ge)(ge)小電(dian)流(liu)電(dian)源或一(yi)個(ge)(ge)斷續(xu)性能(neng)量收(shou)集電(dian)源準(zhun)(zhun)確和(he)安全地給(gei)鋰離子 / 聚合物(wu)、幣(bi)形電(dian)池或薄膜電(dian)池充電(dian)，一(yi)直是難以實現的(de)。

　　從電(dian)(dian)(dian)(dian)池方面來看，盡管技術(shu)(shu)已經(jing)改進(jin)了，但(dan)是便攜式(shi)電(dian)(dian)(dian)(dian)子(zi)設備(bei)的(de)電(dian)(dian)(dian)(dian)池或(huo)電(dian)(dian)(dian)(dian)池組仍然需(xu)要保護和(he)查(cha)驗，以保持電(dian)(dian)(dian)(dian)池在最佳狀(zhuang)態運行。鋰離(li)子(zi) / 聚合物電(dian)(dian)(dian)(dian)池技術(shu)(shu)已經(jing)成熟，是很(hen)多電(dian)(dian)(dian)(dian)子(zi)設備(bei)流行的(de)電(dian)(dian)(dian)(dian)源選擇(ze)，因為這(zhe)類(lei)電(dian)(dian)(dian)(dian)池能(neng)量密度(du)高(gao)、自放電(dian)(dian)(dian)(dian)很(hen)少(shao)、需(xu)要很(hen)少(shao)的(de)維(wei)護、電(dian)(dian)(dian)(dian)壓范圍很(hen)寬并具(ju)有其他一(yi)些(xie)特色。幣(bi)形(xing)電(dian)(dian)(dian)(dian)池能(neng)量密度(du)高(gao)、放電(dian)(dian)(dian)(dian)特性穩(wen)定、重量輕且外形(xing)尺寸小。薄(bo)膜(mo)電(dian)(dian)(dian)(dian)池是一(yi)種(zhong)新出現(xian)的(de)技術(shu)(shu)，優勢是允許非常多的(de)充電(dian)(dian)(dian)(dian)周期次數(shu)，并具(ju)有物理靈活性，即(ji)視最終(zhong)應用(yong)的(de)不(bu)同而不(bu)同，薄(bo)膜(mo)電(dian)(dian)(dian)(dian)池可以做成幾乎任何形(xing)狀(zhuang)。不(bu)過，如果不(bu)能(neng)正確充電(dian)(dian)(dian)(dian)和(he)查(cha)驗，那么所(suo)有這(zhe)些(xie)類(lei)型的(de)電(dian)(dian)(dian)(dian)池都(dou)可能(neng)受到一(yi)些(xie)有害影響。

　　低功耗充(chong)電(dian)器的設計挑戰

　　可調(diao)并聯(lian)基(ji)準(zhun)(zhun)可被設定(ding)以(yi)提供恰當(dang)的(de)電(dian)池(chi)浮置(zhi)電(dian)壓(ya)，但是(shi)這類基(ji)準(zhun)(zhun)缺乏電(dian)池(chi)充(chong)電(dian)器(qi)的(de) NTC 功(gong)(gong)能。更重要的(de)是(shi)，所需(xu)的(de)工(gong)作電(dian)流太高了，以(yi)至于用低功(gong)(gong)率電(dian)源或斷續性電(dian)源給電(dian)池(chi)充(chong)電(dian)是(shi)不現(xian)實的(de)。或者，可以(yi)用一個(ge)齊納二極管、一些電(dian)阻器(qi)、一個(ge) NPN 晶(jing)體(ti)管和一些比較(jiao)器(qi)構(gou)成一個(ge)分(fen)立式(shi)并聯(lian)基(ji)準(zhun)(zhun)，以(yi)提供 NTC 功(gong)(gong)能。不過，這樣的(de)并聯(lian)基(ji)準(zhun)(zhun)仍然(ran)受到前述限制。此外，分(fen)立式(shi)并聯(lian)基(ji)準(zhun)(zhun)實現(xian)起(qi)來比較(jiao)復雜(za)，相比之下，會占(zhan)用更多寶貴的(de) PCB 面(mian)積。

　　典型的電(dian)池充(chong)電(dian)器 IC 需要恒定 DC 輸入電(dian)壓(ya)，而(er)且不能(neng)處理能(neng)量(liang)突發(fa)。不過(guo)，諸如(ru)室內光伏(fu)陣列或(huo)壓(ya)電(dian)換能(neng)器等斷續(xu)性能(neng)量(liang)收(shou)集電(dian)源提(ti)供(gong)的是(shi)功率突發(fa)。要用這(zhe)類能(neng)源給電(dian)池充(chong)電(dian)，一個靜態工作電(dian)流低于(yu) 1uA 的獨特 IC 是(shi)必需的。

　　鋰離(li)子 / 聚合物(wu)化學(xue)組成的(de)電(dian)池提供便攜(xie)式(shi)電(dian)子設備(bei)必需的(de)高(gao)(gao)性能(neng)，但是這(zhe)類電(dian)池必須小心使用。例如，如果用比建(jian)議浮置電(dian)壓高(gao)(gao) 100mV 的(de)電(dian)壓充電(dian)，鋰離(li)子 / 聚合物(wu)電(dian)池可能(neng)變(bian)得不穩定。此外，高(gao)(gao)壓和高(gao)(gao)溫(wen)同時存(cun)在會對電(dian)池壽命產(chan)生有害影響，而且在極(ji)端情況下，可能(neng)導致電(dian)池自毀。就幣形(xing)電(dian)池和薄膜電(dian)池而言(yan)，除(chu)了高(gao)(gao)溫(wen)和高(gao)(gao)壓同時存(cun)在可能(neng)產(chan)生有害影響，還有容量(liang)問題，因(yin)為它們的(de)外形(xing)尺寸(cun)很(hen)小。

　　并聯架構的(de)基本要素(su)和好處

　　并(bing)聯(lian)基(ji)準是(shi)電(dian)流饋送型、兩端子電(dian)路(lu)(lu)，在達到目標電(dian)壓之(zhi)前(qian)不吸取電(dian)流。并(bing)聯(lian)基(ji)準用起來像一個(ge)齊納二極管(guan)，而且(qie)在電(dian)路(lu)(lu)原理圖上常常顯示(shi)為一個(ge)齊納二極管(guan)。不過(guo)，大多(duo)數并(bing)聯(lian)基(ji)準實際上都是(shi)基(ji)于帶隙基(ji)準電(dian)壓的。

　　一(yi)個并聯基(ji)準(zhun)僅需要(yao)單個外部(bu)電(dian)(dian)阻(zu)器來調節(jie)輸出電(dian)(dian)壓(ya)，從而極其容易使用(yong)。沒(mei)有最(zui)高輸入(ru)電(dian)(dian)壓(ya)限制，最(zui)低輸入(ru)電(dian)(dian)壓(ya)由基(ji)準(zhun)電(dian)(dian)壓(ya)值設(she)定，因為需要(yao)一(yi)些空間(jian)以正常運行。

　　此外，并聯(lian)基準在寬電流范圍內有良好的穩定(ding)(ding)性。很多并聯(lian)基準在有大型或(huo)小型容性負載時都是穩定(ding)(ding)的。

　　滿足前述電池充電器 IC 設計限制的(de)(de)任何解決(jue)方案都必須兼有如下(xia)特性：并聯穩壓器的(de)(de)特性;能用低功率連續或(huo)斷(duan)續性電(dian)源充電(dian)的(de)(de)電(dian)池充電(dian) IC 的(de)(de)特性。這樣(yang)的(de)(de)器件還需要保(bao)護鋰(li)離子/聚合物(wu)電(dian)池、幣(bi)形電(dian)池、薄(bo)膜(mo)電(dian)池或(huo)電(dian)池組(zu)的(de)(de)安(an)全，并使電(dian)池或(huo)電(dian)池組(zu)達到(dao)最高性能。

　　凌力(li)爾特開發(fa)了業界第(di)一款并聯架構(gou)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)器(qi)(qi) LTC4070 和(he) LTC4071，以(yi)(yi)(yi)滿足這類應用(yong)的(de)(de)需求。LTC4070 是一款易用(yong)、纖巧的(de)(de)并聯電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)器(qi)(qi)系(xi)統(tong) IC，適(shi)用(yong)于(yu)(yu)鋰(li)離子 / 聚(ju)合(he)物(wu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)、幣形(xing)(xing)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)或薄膜(mo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)。該(gai) IC 的(de)(de)工作電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)為(wei) 450nA，可(ke)(ke)保護電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)，并可(ke)(ke)用(yong)以(yi)(yi)(yi)前不(bu)能使用(yong)的(de)(de)非常小電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)的(de)(de)斷續(xu)性(xing)或連續(xu)性(xing)充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)給這些電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)。增加(jia)一個外部 PMOS 并聯器(qi)(qi)件，LTC4070 的(de)(de)充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)就(jiu)可(ke)(ke)以(yi)(yi)(yi)從 50mA 提高到(dao) 500mA。當電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)溫(wen)度升高時，內部電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)熱(re)量(liang)查驗(yan)器(qi)(qi)降低浮(fu)置電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)，以(yi)(yi)(yi)保護鋰(li)離子 / 聚(ju)合(he)物(wu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)的(de)(de)安全。通過串聯配置幾個 LTC4070，可(ke)(ke)以(yi)(yi)(yi)給由多節(jie)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)組成的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)組充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，并實現各節(jie)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)的(de)(de)容量(liang)平(ping)衡。LTC4070 采用(yong)扁平(ping) (0.75mm) 8 引線 2mm x 3mm DFN 封裝，僅用(yong)單個外部電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻器(qi)(qi) (要(yao)求與輸入電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)串聯) 就(jiu)能組成一個完整和(he)超緊(jin)湊的(de)(de)充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)器(qi)(qi)解決(jue)方案。該(gai)器(qi)(qi)件的(de)(de)功能集(ji)使其非常適(shi)用(yong)于(yu)(yu)連續(xu)性(xing)和(he)斷續(xu)性(xing)低功率充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)應用(yong)，包括鋰(li)離子 / 聚(ju)合(he)物(wu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)備(bei)份、薄膜(mo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)、幣形(xing)(xing)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)、存儲器(qi)(qi)備(bei)份、太陽(yang)能供(gong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)系(xi)統(tong)、嵌入式(shi)汽車和(he)能量(liang)收(shou)集(ji)。

　　LTC4070提(ti)供引腳可選的 4.0V、4.1V 和(he) 4.2V 設置，其準(zhun)確(que)度(du)為 1% 的電(dian)(dian)池(chi)(chi)浮置電(dian)(dian)壓允許用戶在電(dian)(dian)池(chi)(chi)能量密度(du)和(he)壽命之間(jian)進(jin)行取(qu)舍。獨(du)立的低電(dian)(dian)池(chi)(chi)電(dian)(dian)量和(he)高(gao)電(dian)(dian)池(chi)(chi)電(dian)(dian)量監察(cha)狀態(tai)輸出指示放(fang)電(dian)(dian)或完全充電(dian)(dian)的電(dian)(dian)池(chi)(chi)。再加上一個與負載串聯(lian)的外部 P-FET，該(gai)低電(dian)(dian)池(chi)(chi)電(dian)(dian)量狀態(tai)輸出可實現鎖(suo)斷功(gong)能，該(gai)功(gong)能自動斷接系統負載和(he)電(dian)(dian)池(chi)(chi)，以(yi)防止電(dian)(dian)池(chi)(chi)深(shen)度(du)放(fang)電(dian)(dian)。

　　除了緊(jin)湊的 2mm x 3mm 8 引(yin)線(xian) DFN 封裝，LTC4070 還采(cai)用(yong) 8 引(yin)線(xian) MSOP。這些器件規定在 -40?C 至(zhi) 125?C 的溫度范圍內工(gong)作。

　　通過防止電(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)壓超過設定水平，LTC4070 提供了一個(ge)簡單、可(ke)靠(kao)、高(gao)性(xing)能的(de)電(dian)(dian)(dian)池(chi)(chi)保(bao)護和充電(dian)(dian)(dian)解決方案(an)。其(qi)并聯(lian)架構在輸入電(dian)(dian)(dian)源和電(dian)(dian)(dian)池(chi)(chi)之間僅需(xu)要一個(ge)電(dian)(dian)(dian)阻(zu)器(qi)，就(jiu)可(ke)應對多種電(dian)(dian)(dian)池(chi)(chi)應用。當輸入電(dian)(dian)(dian)源去掉，且(qie)電(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)壓低于高(gao)的(de)電(dian)(dian)(dian)池(chi)(chi)輸出門(men)限時(shi)，LTC4070 僅從電(dian)(dian)(dian)池(chi)(chi)吸(xi)取 450nA 電(dian)(dian)(dian)流。

　　當(dang)電(dian)(dian)(dian)池電(dian)(dian)(dian)壓(ya)低于(yu)設定的浮(fu)置電(dian)(dian)(dian)壓(ya)時，充電(dian)(dian)(dian)速率由(you)輸入電(dian)(dian)(dian)壓(ya)、電(dian)(dian)(dian)池電(dian)(dian)(dian)壓(ya)和(he)輸入電(dian)(dian)(dian)阻(zu)器決定：

　　ICHG = (VIN ? VBAT) / RIN

　　當電(dian)池(chi)電(dian)壓接(jie)近浮置(zhi)電(dian)壓時(shi)，LTC4070 從電(dian)池(chi)分(fen)走一部分(fen)電(dian)流，從而降低了(le)充電(dian)電(dian)流。在整(zheng)個溫度范圍內變化浮置(zhi)電(dian)壓的準確度為 ±1% 時(shi)，LTC4070 可以分(fen)走高達 50mA 的電(dian)流。分(fen)流限(xian)制了(le)最(zui)大充電(dian)電(dian)流，不過(guo)通過(guo)增加一個外部 P 溝道 MOSFET，50mA 的內部分(fen)流能(neng)力(li)還可以提高，參見圖 1。

　　在內部，LTC4070 采用了一個由放大器(qi)(qi) EA (參(can)見(jian)圖(tu) 2) 驅動的 P 溝道 MOSFET。VCC 和 GND 之間(jian)的電(dian)壓(ya)(ya)達(da)到(dao) VF (即(ji)并聯電(dian)壓(ya)(ya)) 之前，流(liu)(liu)(liu)經該(gai)器(qi)(qi)件的電(dian)流(liu)(liu)(liu)為零。VF 可(ke)以由 ADJ 和 NTC 改變，但始終在 3.8V 到(dao) 4.2V 之間(jian)。如(ru)果 VCC 電(dian)壓(ya)(ya)低于這個值，那(nei)么 PFET 中的電(dian)流(liu)(liu)(liu)為零。如(ru)果 VCC電(dian)壓(ya)(ya)試圖(tu)上升到(dao)超過 VF，那(nei)么電(dian)流(liu)(liu)(liu)將(jiang)流(liu)(liu)(liu)過該(gai)器(qi)(qi)件，以防(fang)止電(dian)壓(ya)(ya)上升，這就是分(fen)流(liu)(liu)(liu)。

　　工作電(dian)(dian)流是(shi)給(gei)該芯片中(zhong)其余所有電(dian)(dian)路(lu)供電(dian)(dian)所需的電(dian)(dian)流。如果不存在外(wai)部電(dian)(dian)源(yuan)，那么(me)這(zhe)就是(shi)從電(dian)(dian)池吸取的電(dian)(dian)流。

　　當(dang)電(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)壓(ya)低時(shi)，更多的電(dian)(dian)(dian)(dian)壓(ya)加在輸入電(dian)(dian)(dian)(dian)阻器兩端，因此進(jin)入電(dian)(dian)(dian)(dian)池(chi)的電(dian)(dian)(dian)(dian)流(liu) (即充(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)) 略(lve)大于電(dian)(dian)(dian)(dian)池(chi)完(wan)全充(chong)電(dian)(dian)(dian)(dian)時(shi)的電(dian)(dian)(dian)(dian)流(liu)。當(dang)電(dian)(dian)(dian)(dian)池(chi)充(chong)滿(man)電(dian)(dian)(dian)(dian)時(shi)，將(jiang)沒有電(dian)(dian)(dian)(dian)流(liu)進(jin)入電(dian)(dian)(dian)(dian)池(chi)，所有的輸入電(dian)(dian)(dian)(dian)流(liu)都將(jiang)進(jin)入分流(liu)器。

　　工作電(dian)(dian)流很重要(yao)，因為它給(gei)“實際”輸入電(dian)(dian)源(yuan)(yuan)的電(dian)(dian)流能(neng)(neng)(neng)(neng)力(li)設定(ding)了(le)一個低限制。顯然，一個僅有 100nA驅動能(neng)(neng)(neng)(neng)力(li)的輸入電(dian)(dian)源(yuan)(yuan)不可(ke)能(neng)(neng)(neng)(neng)給(gei)采用(yong) LTC4070 的電(dian)(dian)池充電(dian)(dian)。不過，如果有 1uA 的驅動能(neng)(neng)(neng)(neng)力(li)，就能(neng)(neng)(neng)(neng)剩下(xia)少(shao)量電(dian)(dian)流去(qu)充電(dian)(dian)。如果能(neng)(neng)(neng)(neng)得到 10uA 的驅動能(neng)(neng)(neng)(neng)力(li)，那么該電(dian)(dian)流 90% 以上(shang)都可(ke)用(yong)于充電(dian)(dian)。

　　NTC 電池(chi)查驗電路保(bao)護電池(chi)

　　LTC4070 用(yong)一個通過(guo)熱(re)量耦合到電(dian)池的負溫(wen)度系數(shu)熱(re)敏電(dian)阻測量電(dian)池溫(wen)度。NTC 熱(re)敏電(dian)阻的溫(wen)度特(te)性在(zai)電(dian)阻-溫(wen)度轉換表中規定(ding)。在(zai)溫(wen)度高于 40°C 以后，每上升 10°C，內(nei)部 NTC 電(dian)路就降(jiang)低一次(ci)浮置電(dian)壓，以防止(zhi)電(dian)池過(guo)熱(re) (參見圖 3 以了解詳(xiang)細信息)。

　　LTC4070 采(cai)用一(yi)個(ge)電(dian)(dian)阻值(zhi)之比(bi)來(lai)測量(liang)電(dian)(dian)池(chi)溫度(du)。LTC4070 在 NTCBIAS 與(yu) GND 引(yin)腳之間布設了(le)一(yi)個(ge)具 4 個(ge)抽頭(tou)的內(nei)部(bu)固(gu)定電(dian)(dian)阻分壓器。定期地將這些抽頭(tou)上的電(dian)(dian)壓與(yu) NTC 引(yin)腳上的電(dian)(dian)壓進行比(bi)較，以(yi)測量(liang)電(dian)(dian)池(chi)溫度(du)。為了(le)節省功(gong)率(lv)，通過以(yi)大約每 1.5s 一(yi)次的頻度(du)把(ba) NTCBIAS 引(yin)腳偏置至 VCC 來(lai)定期測量(liang)電(dian)(dian)池(chi)溫度(du)。

    LTC4070 具(ju)有(you)一(yi)個(ge)與(yu) ADJ 引腳相(xiang)(xiang)連的(de)內(nei)置(zhi)(zhi)三態解(jie)碼器，用(yong)以(yi)(yi)提供(gong) 3 種可(ke)編程浮(fu)置(zhi)(zhi)電壓(ya)(ya)：4.0V、4.1V、或 4.2V。當(dang) ADJ 引腳連接至(zhi) GND、浮(fu)置(zhi)(zhi)或連接至(zhi) VCC 時(shi)，浮(fu)置(zhi)(zhi)電壓(ya)(ya)將被分別設置(zhi)(zhi)為 4.0V、4.1V 或 4.2V。大約每(mei) 1.5s 對 ADJ 引腳的(de)狀(zhuang)態進(jin)行一(yi)次采(cai)樣(yang)。當(dang) ADJ 引腳被采(cai)樣(yang)時(shi)，LTC4070 在(zai)其上施加一(yi)個(ge)相(xiang)(xiang)對較低的(de)阻(zu)抗(kang)電壓(ya)(ya)。這種做法可(ke)以(yi)(yi)防止(zhi)低水平的(de)電路(lu)板漏電流(liu)破壞設定的(de)浮(fu)置(zhi)(zhi)電壓(ya)(ya)。免除電阻(zu)器不(bu)僅縮減了解(jie)決方案的(de)外形(xing)尺寸，而且還由于無需使(shi)用(yong)大阻(zu)值的(de)電阻(zu)器而降低了靜態電流(liu)。

　　另外，該器件(jian)還具有狀態輸(shu)(shu)出(chu)及發送指(zhi)示信(xin)號(hao)(hao)的能力。高(gao)電池(chi)電量(liang)監視(shi)器輸(shu)(shu)出(chu) (HBO) 是一個(ge)高(gao)態有效 CMOS 輸(shu)(shu)出(chu)，當電池(chi)充滿(man)電且電流通過分路離開 BAT 時，該輸(shu)(shu)出(chu)將發出(chu)指(zhi)示信(xin)號(hao)(hao)。低(di)電池(chi)電量(liang)監視(shi)器輸(shu)(shu)出(chu) (LBO) 也是一個(ge)高(gao)態有效 CMOS 輸(shu)(shu)出(chu)，當電池(chi)放電至(zhi) 3.2V 以下(xia)時，此(ci)輸(shu)(shu)出(chu)將發出(chu)對應(ying)的指(zhi)示信(xin)號(hao)(hao)。最(zui)后，外部(bu)驅動器輸(shu)(shu)出(chu)引腳 DRV 可連接至(zhi)外部(bu) P-FET 的柵極以增加分路電流，從而滿(man)足那些(xie)需(xu)要 50mA 以上(shang)充電電流 (最(zui)大 500mA) 的應(ying)用。

　　LTC4071 集成電池組(zu)保護功(gong)能

　　LTC4071 也是(shi)一(yi)個并聯電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)器系統，而且(qie)還是(shi)首款具有集(ji)(ji)成型電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)組保(bao)護功(gong)能 (包括(kuo)低(di)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)量(liang)斷(duan)(duan)接(jie)(jie)) 的(de)(de)(de)(de)器件。相(xiang)(xiang)比于(yu) LTC4070，LTC4071 的(de)(de)(de)(de)不(bu)同(tong)之(zhi)(zhi)處(chu)包括(kuo)：其擁有集(ji)(ji)成型電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)組保(bao)護功(gong)能 (低(di)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)量(liang)斷(duan)(duan)接(jie)(jie)) 、但(dan)充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流能力(li)較(jiao)低(di) (50mA)、靜態電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流較(jiao)高 (550nA) 、且(qie)不(bu)具備 LBO。對(dui)于(yu)避免低(di)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)量(liang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)由于(yu)自放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)而受損而言，低(di)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)量(liang)斷(duan)(duan)接(jie)(jie)是(shi)一(yi)種必(bi)需(xu)的(de)(de)(de)(de)關鍵性功(gong)能。雖(sui)然 LTC4070 能夠(gou)利用 LBO 和一(yi)個外(wai)部(bu) P-FET 來(lai)實現(xian)低(di)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)量(liang)斷(duan)(duan)接(jie)(jie)功(gong)能，但(dan)該(gai) IC 仍將繼續(xu)從(cong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)消耗全(quan)部(bu) IQ (約 0.5μA)。即使(shi)是(shi)如此之(zhi)(zhi)小的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)漏(lou)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流也會在一(yi)夜之(zhi)(zhi)間導致(zhi)低(di)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)量(liang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)的(de)(de)(de)(de)損壞。相(xiang)(xiang)反，LTC4071 集(ji)(ji)成了(le)一(yi)個徹底的(de)(de)(de)(de)低(di)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)量(liang)斷(duan)(duan)接(jie)(jie)功(gong)能，當斷(duan)(duan)接(jie)(jie)時，從(cong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)吸取(qu)的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流接(jie)(jie)近零(ling) (在室(shi)溫時 <1nA，在 125°C 時 < 25nA)。為(wei)了(le)在 LTC4071 中提供這一(yi)功(gong)能，相(xiang)(xiang)應于(yu) LTC4070 的(de)(de)(de)(de) LBO 和 DRV 引腳被去(qu)掉了(le)。參(can)見圖 4 以了(le)解(jie)詳細信(xin)息。這使(shi) LTC4071 的(de)(de)(de)(de)最大分流電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流固定(ding)為(wei) 50mA (LTC4070 是(shi) 50mA，但(dan)采(cai)用一(yi)個外(wai)部(bu) FET，就能達到 500mA)，而且(qie)將該(gai) IC 的(de)(de)(de)(de)靜態電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流提高到了(le) 550nA (LTC4070 的(de)(de)(de)(de)靜態電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流為(wei) 450nA)。下表 1 總結了(le)這兩(liang)個相(xiang)(xiang)互(hu)關聯的(de)(de)(de)(de) IC 之(zhi)(zhi)間的(de)(de)(de)(de)差(cha)別(bie)。

　　結論

　　并(bing)聯基準有(you)(you)很(hen)多(duo)應(ying)(ying)用，而(er)且視其功(gong)能的(de)不(bu)同而(er)不(bu)同，并(bing)聯基準甚至可(ke)以用來給電(dian)(dian)池(chi)(chi)充電(dian)(dian)。不(bu)過，這種類型的(de)應(ying)(ying)用有(you)(you)很(hen)多(duo)缺點，包(bao)括大靜(jing)態電(dian)(dian)流和(he)(he)缺乏電(dian)(dian)池(chi)(chi)保(bao)護(hu)功(gong)能。現在，有(you)(you)了(le)(le)合適的(de) DC-DC 轉換器(qi)(qi)或電(dian)(dian)池(chi)(chi)充電(dian)(dian)器(qi)(qi)，因(yin)此(ci)可(ke)以對(dui)低功(gong)率(lv)能量收集應(ying)(ying)用進行查驗了(le)(le)。凌力(li)爾特公司開發了(le)(le) LTC4070 和(he)(he) LTC4071 并(bing)聯充電(dian)(dian)器(qi)(qi)系統，這兩款器(qi)(qi)件(jian)適用于(yu)鋰離子(zi) / 聚(ju)合物電(dian)(dian)池(chi)(chi)、幣形電(dian)(dian)池(chi)(chi)、薄(bo)膜電(dian)(dian)池(chi)(chi)和(he)(he)電(dian)(dian)池(chi)(chi)組，可(ke)為具有(you)(you)低功(gong)率(lv)電(dian)(dian)源的(de)領先應(ying)(ying)用提供一(yi)種簡單、有(you)(you)效的(de)電(dian)(dian)池(chi)(chi)充電(dian)(dian)和(he)(he)電(dian)(dian)池(chi)(chi)組保(bao)護(hu)解決方案。