锂电(dian)池(chi)保护(hu)板根据使用IC,电(dian)压等不同(tong)而电(dian)路及参数(shu)有(you)所不同(tong),保护(hu)板有(you)两个核心部件：一块保护(hu)IC，它是由精(jing)确(que)的(de)比(bi)较器来获得(de)可靠的(de)保护(hu)参数(shu)；另(ling)外是MOSFET串(chuan)在主充放电(dian)回(hui)路中担(dan)当高(gao)速开(kai)关，执(zhi)行保护(hu)动(dong)作。下(xia)面以DW01 配MOS管8205A进行讲解:

激活保护板(ban)的方(fang)法：当保护板(ban)P+、P-没(mei)有输出处(chu)于保护状(zhuang)态，可(ke)以短(duan)路B-、P-来(lai)激活保护板(ban)，这时，Dout、Cout均会处(chu)于低电平（保护IC此两端(duan)口(kou)是高电平保护，低电平常态）状(zhuang)态打(da)开两个MOS开关。

1.锂电池保护板其正常工作过程

当(dang)电(dian)(dian)芯电(dian)(dian)压(ya)(ya)在2.5V至(zhi)4.3V之间时(shi)，DW01 的(de)(de)(de)第(di)1脚(jiao)、第(di)3脚(jiao)均(jun)输出(chu)(chu)高电(dian)(dian)平(ping)(等于供电(dian)(dian)电(dian)(dian)压(ya)(ya))，第(di)二(er)脚(jiao)电(dian)(dian)压(ya)(ya)为0V。此(ci)时(shi)DW01 的(de)(de)(de)第(di)1脚(jiao) 、第(di)3脚(jiao)电(dian)(dian)压(ya)(ya)将分别加到8205A的(de)(de)(de)第(di)5、4脚(jiao)，8205A内的(de)(de)(de)两(liang)个电(dian)(dian)子开(kai)关因其G极接(jie)到来自DW01 的(de)(de)(de)电(dian)(dian)压(ya)(ya)，故(gu)均(jun)处于导通(tong)(tong)状态，即两(liang)个电(dian)(dian)子开(kai)关均(jun)处于开(kai)状态。此(ci)时(shi)电(dian)(dian)芯的(de)(de)(de)负(fu)极与保护板(ban)的(de)(de)(de)P-端相当(dang)于直接(jie)连通(tong)(tong)，保护板(ban)有(you)电(dian)(dian)压(ya)(ya)输出(chu)(chu)。

2.保护板过放电保护控制原理

当电(dian)(dian)(dian)(dian)(dian)(dian)芯(xin)(xin)通过外接(jie)的(de)(de)(de)(de)(de)负载进行放(fang)电(dian)(dian)(dian)(dian)(dian)(dian)时(shi)(shi),电(dian)(dian)(dian)(dian)(dian)(dian)芯(xin)(xin)的(de)(de)(de)(de)(de)电(dian)(dian)(dian)(dian)(dian)(dian)压(ya)(ya)(ya)(ya)将(jiang)(jiang)慢慢降低(di),同时(shi)(shi)DW01 内部(bu)将(jiang)(jiang)通过R1电(dian)(dian)(dian)(dian)(dian)(dian)阻实时(shi)(shi)监测(ce)电(dian)(dian)(dian)(dian)(dian)(dian)芯(xin)(xin)电(dian)(dian)(dian)(dian)(dian)(dian)压(ya)(ya)(ya)(ya),当电(dian)(dian)(dian)(dian)(dian)(dian)芯(xin)(xin)电(dian)(dian)(dian)(dian)(dian)(dian)压(ya)(ya)(ya)(ya)下降到约2.3V时(shi)(shi)DW01 将(jiang)(jiang)认为(wei)(wei)电(dian)(dian)(dian)(dian)(dian)(dian)芯(xin)(xin)电(dian)(dian)(dian)(dian)(dian)(dian)压(ya)(ya)(ya)(ya)已处于过放(fang)电(dian)(dian)(dian)(dian)(dian)(dian)电(dian)(dian)(dian)(dian)(dian)(dian)压(ya)(ya)(ya)(ya)状(zhuang)态，便(bian)立即(ji)(ji)断开(kai)第(di)(di)1脚的(de)(de)(de)(de)(de)输(shu)出电(dian)(dian)(dian)(dian)(dian)(dian)压(ya)(ya)(ya)(ya)，使第(di)(di)1脚电(dian)(dian)(dian)(dian)(dian)(dian)压(ya)(ya)(ya)(ya)变为(wei)(wei)0V，8205A内的(de)(de)(de)(de)(de)开(kai)关管(guan)(guan)因第(di)(di)5脚无电(dian)(dian)(dian)(dian)(dian)(dian)压(ya)(ya)(ya)(ya)而关闭。此时(shi)(shi)电(dian)(dian)(dian)(dian)(dian)(dian)芯(xin)(xin)的(de)(de)(de)(de)(de)B-与保(bao)(bao)护(hu)板(ban)(ban)的(de)(de)(de)(de)(de)P-之(zhi)间处于断开(kai)状(zhuang)态。即(ji)(ji)电(dian)(dian)(dian)(dian)(dian)(dian)芯(xin)(xin)的(de)(de)(de)(de)(de)放(fang)电(dian)(dian)(dian)(dian)(dian)(dian)回路(lu)被切(qie)断，电(dian)(dian)(dian)(dian)(dian)(dian)芯(xin)(xin)将(jiang)(jiang)停止放(fang)电(dian)(dian)(dian)(dian)(dian)(dian)。保(bao)(bao)护(hu)板(ban)(ban)处于过放(fang)电(dian)(dian)(dian)(dian)(dian)(dian)状(zhuang)态并一直保(bao)(bao)持。等(deng)到保(bao)(bao)护(hu)板(ban)(ban)的(de)(de)(de)(de)(de)P 与P-间接(jie)上充(chong)电(dian)(dian)(dian)(dian)(dian)(dian)电(dian)(dian)(dian)(dian)(dian)(dian)压(ya)(ya)(ya)(ya)后(hou)，DW01 经B-检测(ce)到充(chong)电(dian)(dian)(dian)(dian)(dian)(dian)电(dian)(dian)(dian)(dian)(dian)(dian)压(ya)(ya)(ya)(ya)后(hou)便(bian)立即(ji)(ji)停止过放(fang)电(dian)(dian)(dian)(dian)(dian)(dian)状(zhuang)态，重新在第(di)(di)1脚输(shu)出高(gao)电(dian)(dian)(dian)(dian)(dian)(dian)压(ya)(ya)(ya)(ya)，使8205A内的(de)(de)(de)(de)(de)过放(fang)电(dian)(dian)(dian)(dian)(dian)(dian)控制管(guan)(guan)导通，即(ji)(ji)电(dian)(dian)(dian)(dian)(dian)(dian)芯(xin)(xin)的(de)(de)(de)(de)(de)B-与保(bao)(bao)护(hu)板(ban)(ban)的(de)(de)(de)(de)(de)P-又(you)重新接(jie)上，电(dian)(dian)(dian)(dian)(dian)(dian)芯(xin)(xin)经充(chong)电(dian)(dian)(dian)(dian)(dian)(dian)器直接(jie)充(chong)电(dian)(dian)(dian)(dian)(dian)(dian)。

3.保护板过充电保护控制原理

当电(dian)(dian)(dian)(dian)(dian)池(chi)通(tong)过充(chong)(chong)电(dian)(dian)(dian)(dian)(dian)器正常(chang)充(chong)(chong)电(dian)(dian)(dian)(dian)(dian)时(shi)(shi),随着充(chong)(chong)电(dian)(dian)(dian)(dian)(dian)时(shi)(shi)间(jian)的(de)增加(jia),电(dian)(dian)(dian)(dian)(dian)芯的(de)电(dian)(dian)(dian)(dian)(dian)压将越(yue)来越(yue)高，当电(dian)(dian)(dian)(dian)(dian)芯电(dian)(dian)(dian)(dian)(dian)压升高到4.4V时(shi)(shi),DW01 将认为(wei)电(dian)(dian)(dian)(dian)(dian)芯电(dian)(dian)(dian)(dian)(dian)压已处(chu)于过充(chong)(chong)电(dian)(dian)(dian)(dian)(dian)电(dian)(dian)(dian)(dian)(dian)压状(zhuang)态(tai)，便立即断(duan)开(kai)(kai)第(di)3脚(jiao)的(de)输出(chu)电(dian)(dian)(dian)(dian)(dian)压，使第(di)3脚(jiao)电(dian)(dian)(dian)(dian)(dian)压变为(wei)0V，8205A内的(de)开(kai)(kai)关管(guan)因第(di)4脚(jiao)无(wu)电(dian)(dian)(dian)(dian)(dian)压而关闭。此(ci)时(shi)(shi)电(dian)(dian)(dian)(dian)(dian)芯的(de)B-与保(bao)(bao)(bao)护板(ban)(ban)的(de)P-之间(jian)处(chu)于断(duan)开(kai)(kai)状(zhuang)态(tai)。即电(dian)(dian)(dian)(dian)(dian)芯的(de)充(chong)(chong)电(dian)(dian)(dian)(dian)(dian)回路(lu)被切断(duan)，电(dian)(dian)(dian)(dian)(dian)芯将停止充(chong)(chong)电(dian)(dian)(dian)(dian)(dian)。保(bao)(bao)(bao)护板(ban)(ban)处(chu)于过充(chong)(chong)电(dian)(dian)(dian)(dian)(dian)状(zhuang)态(tai)并一(yi)直保(bao)(bao)(bao)持。等到保(bao)(bao)(bao)护板(ban)(ban)的(de)P 与P-间(jian)接上(shang)放(fang)电(dian)(dian)(dian)(dian)(dian)负载后，因此(ci)时(shi)(shi)虽然过充(chong)(chong)电(dian)(dian)(dian)(dian)(dian)控(kong)制开(kai)(kai)关管(guan)关闭,但其内部的(de)二极管(guan)正方向与放(fang)电(dian)(dian)(dian)(dian)(dian)回路(lu)的(de)方向相同(tong),故放(fang)电(dian)(dian)(dian)(dian)(dian)回路(lu)可(ke)以(yi)进行放(fang)电(dian)(dian)(dian)(dian)(dian),当电(dian)(dian)(dian)(dian)(dian)芯的(de)电(dian)(dian)(dian)(dian)(dian)压被放(fang)到低于4.3V时(shi)(shi),DW01 停止过充(chong)(chong)电(dian)(dian)(dian)(dian)(dian)保(bao)(bao)(bao)护状(zhuang)态(tai)重新在第(di)3脚(jiao)输出(chu)高电(dian)(dian)(dian)(dian)(dian)压，使8205A内的(de)过充(chong)(chong)电(dian)(dian)(dian)(dian)(dian)控(kong)制管(guan)导通(tong)，即电(dian)(dian)(dian)(dian)(dian)芯的(de)B-与保(bao)(bao)(bao)护板(ban)(ban)P-又重新接上(shang)，电(dian)(dian)(dian)(dian)(dian)芯又能进行正常(chang)的(de)充(chong)(chong)放(fang)电(dian)(dian)(dian)(dian)(dian).

4.保护板短路保护控制原理

在保(bao)护板对外(wai)放电(dian)(dian)(dian)(dian)的(de)(de)过(guo)程中，8205A内(nei)(nei)的(de)(de)两(liang)个电(dian)(dian)(dian)(dian)子(zi)开(kai)关(guan)(guan)并不完全等效(xiao)于(yu)两(liang)个机(ji)械开(kai)关(guan)(guan)，而(er)是等效(xiao)于(yu)两(liang)个电(dian)(dian)(dian)(dian)阻很(hen)(hen)小(xiao)的(de)(de)电(dian)(dian)(dian)(dian)阻，并称为(wei)8205A的(de)(de)导通(tong)(tong)内(nei)(nei)阻， 每个开(kai)关(guan)(guan)的(de)(de)导通(tong)(tong)内(nei)(nei)阻约为(wei)30m/U 03a9共约为(wei)60m/U 03a9，加在G极(ji)上(shang)的(de)(de)电(dian)(dian)(dian)(dian)压(ya)(ya)实际上(shang)是直接控制每个开(kai)关(guan)(guan)管(guan)(guan)的(de)(de)导通(tong)(tong)电(dian)(dian)(dian)(dian)阻的(de)(de)大(da)小(xiao)当(dang)G极(ji)电(dian)(dian)(dian)(dian)压(ya)(ya)大(da)于(yu)1V时(shi)，开(kai)关(guan)(guan)管(guan)(guan)的(de)(de)导通(tong)(tong)内(nei)(nei)阻很(hen)(hen)小(xiao)(几(ji)十毫欧(ou))，相当(dang)于(yu)开(kai)关(guan)(guan)闭合，当(dang)G极(ji)电(dian)(dian)(dian)(dian)压(ya)(ya)小(xiao)于(yu)0.7V以下时(shi)，开(kai)关(guan)(guan)管(guan)(guan)的(de)(de)导通(tong)(tong)内(nei)(nei)阻很(hen)(hen)大(da)(几(ji)MΩ)，相当(dang)于(yu)开(kai)关(guan)(guan)断(duan)开(kai)。电(dian)(dian)(dian)(dian)压(ya)(ya)UA就是8205A的(de)(de)导通(tong)(tong)内(nei)(nei)阻与放电(dian)(dian)(dian)(dian)电(dian)(dian)(dian)(dian)流(liu)(liu)(liu)产生的(de)(de)电(dian)(dian)(dian)(dian)压(ya)(ya)，负(fu)载电(dian)(dian)(dian)(dian)流(liu)(liu)(liu)增(zeng)大(da)则UA必然增(zeng)大(da),因(yin)UA0.006L×IUA又称为(wei)8205A的(de)(de)管(guan)(guan)压(ya)(ya)降，UA可以简接表明放电(dian)(dian)(dian)(dian)电(dian)(dian)(dian)(dian)流(liu)(liu)(liu)的(de)(de)大(da)小(xiao)。上(shang)升到(dao)0.2V时(shi)便认为(wei)负(fu)载电(dian)(dian)(dian)(dian)流(liu)(liu)(liu)到(dao)达了(le)极(ji)限(xian)值，于(yu)是停止第(di)1脚的(de)(de)输(shu)出(chu)电(dian)(dian)(dian)(dian)压(ya)(ya)，使第(di)1脚电(dian)(dian)(dian)(dian)压(ya)(ya)变(bian)为(wei)0V、8205A内(nei)(nei)的(de)(de)放电(dian)(dian)(dian)(dian)控制管(guan)(guan)关(guan)(guan)闭，切断(duan)电(dian)(dian)(dian)(dian)芯(xin)的(de)(de)放电(dian)(dian)(dian)(dian)回路(lu)，将关(guan)(guan)断(duan)放电(dian)(dian)(dian)(dian)控制管(guan)(guan)。换言之DW01 允许输(shu)出(chu)的(de)(de)最大(da)电(dian)(dian)(dian)(dian)流(liu)(liu)(liu)是3.3A，实现了(le)过(guo)电(dian)(dian)(dian)(dian)流(liu)(liu)(liu)保(bao)护。

5. 短路保护控制过程

短(duan)路保(bao)(bao)(bao)护(hu)(hu)(hu)(hu)是过(guo)电(dian)(dian)流(liu)保(bao)(bao)(bao)护(hu)(hu)(hu)(hu)的(de)一(yi)(yi)种极限形式，其(qi)控制过(guo)程及(ji)原(yuan)理与过(guo)电(dian)(dian)流(liu)保(bao)(bao)(bao)护(hu)(hu)(hu)(hu)一(yi)(yi)样，短(duan)路只是在(zai)相(xiang)当于在(zai)P P-间(jian)加上(shang)一(yi)(yi)个阻(zu)值小的(de)电(dian)(dian)阻(zu)(约为0Ω)使保(bao)(bao)(bao)护(hu)(hu)(hu)(hu)板的(de)负载电(dian)(dian)流(liu)瞬(shun)时达(da)到(dao)10A以上(shang)，保(bao)(bao)(bao)护(hu)(hu)(hu)(hu)板立即进行过(guo)电(dian)(dian)流(liu)保(bao)(bao)(bao)护(hu)(hu)(hu)(hu)。

6.8205A产品附件

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锂电(dian)池(chi)保护板

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