mos管开启电压

开(kai)(kai)(kai)启(qi)电(dian)(dian)(dian)压(ya)(ya)(ya)(ya)(ya)(ya)(YGS（th））也(ye)称为(wei)“栅(zha)极阈值(zhi)(zhi)电(dian)(dian)(dian)压(ya)(ya)(ya)(ya)(ya)(ya)”，这个(ge)数值(zhi)(zhi)的(de)(de)选(xuan)择在(zai)这里主要与用作(zuo)比拟器的(de)(de)运(yun)放(fang)(fang)有(you)火。VMOS不像BJT，栅(zha)极相关(guan)于源极需求有(you)一(yi)定(ding)的(de)(de)电(dian)(dian)(dian)压(ya)(ya)(ya)(ya)(ya)(ya)才(cai)干开(kai)(kai)(kai)通，这个(ge)电(dian)(dian)(dian)压(ya)(ya)(ya)(ya)(ya)(ya)的(de)(de)最(zui)低(di)值(zhi)(zhi)（通常是(shi)一(yi)个(ge)范(fan)围(wei)）称为(wei)开(kai)(kai)(kai)启(qi)电(dian)(dian)(dian)压(ya)(ya)(ya)(ya)(ya)(ya)，饱和导通电(dian)(dian)(dian)压(ya)(ya)(ya)(ya)(ya)(ya)普通为(wei)开(kai)(kai)(kai)启(qi)电(dian)(dian)(dian)压(ya)(ya)(ya)(ya)(ya)(ya)的(de)(de)一(yi)倍左右(you)，假(jia)如(ru)技术手(shou)册给出(chu)(chu)(chu)的(de)(de)开(kai)(kai)(kai)启(qi)电(dian)(dian)(dian)压(ya)(ya)(ya)(ya)(ya)(ya)是(shi)一(yi)个(ge)范(fan)围(wei)，取最(zui)大值(zhi)(zhi)。VMOS的(de)(de)开(kai)(kai)(kai)启(qi)电(dian)(dian)(dian)压(ya)(ya)(ya)(ya)(ya)(ya)普通为(wei)5V左右(you)，低(di)开(kai)(kai)(kai)启(qi)电(dian)(dian)(dian)压(ya)(ya)(ya)(ya)(ya)(ya)的(de)(de)种类有(you)2V左右(you)的(de)(de)。假(jia)如(ru)采用5. 5V丁作(zuo)电(dian)(dian)(dian)压(ya)(ya)(ya)(ya)(ya)(ya)的(de)(de)运(yun)放(fang)(fang)，其(qi)输出(chu)(chu)(chu)电(dian)(dian)(dian)平(ping)最(zui)大约为(wei)土2.5V，即便(bian)采用低(di)开(kai)(kai)(kai)启(qi)电(dian)(dian)(dian)压(ya)(ya)(ya)(ya)(ya)(ya)的(de)(de)VMOS，如(ru)图2.6中的(de)(de)2SK2313，最(zui)低(di)驱(qu)动电(dian)(dian)(dian)平(ping)也(ye)至(zhi)少为(wei)土5V，因而依据上文(wen)关(guan)于运(yun)放(fang)(fang)的(de)(de)选(xuan)择准绳，5.5V工作(zuo)电(dian)(dian)(dian)压(ya)(ya)(ya)(ya)(ya)(ya)的(de)(de)运(yun)放(fang)(fang)实践上是(shi)不能用的(de)(de)，引荐的(de)(de)工作(zuo)电(dian)(dian)(dian)压(ya)(ya)(ya)(ya)(ya)(ya)最(zui)低(di)为(wei)±6V，由于运(yun)放(fang)(fang)的(de)(de)最(zui)高输出(chu)(chu)(chu)电(dian)(dian)(dian)平(ping)通常会略低(di)于工作(zuo)电(dian)(dian)(dian)压(ya)(ya)(ya)(ya)(ya)(ya)，即便(bian)是(shi)近年来开(kai)(kai)(kai)端普遍应用的(de)(de)“轨(gui)至(zhi)轨(gui)”输入／输出(chu)(chu)(chu)的(de)(de)运(yun)放(fang)(fang)也(ye)是(shi)如(ru)此。

P沟(gou)道(dao)VMOS当(dang)然也能用，只是驱(qu)动办(ban)法与N沟(gou)道(dao)相反。不(bu)过，直到现在，与N沟(gou)通(tong)(tong)(tong)(tong)同(tong)一系列同(tong)电压(ya)规格(ge)的P沟(gou)通(tong)(tong)(tong)(tong)的VMOS，普(pu)通(tong)(tong)(tong)(tong)电流规格(ge)比N沟(gou)道(dao)的低，而饱(bao)和导通(tong)(tong)(tong)(tong)电压(ya)比N沟(gou)道(dao)高。因而选N沟(gou)道(dao)而不(bu)选P沟(gou)道(dao)。

1、电压规格(VDSS)

俗称耐压(ya)(ya)(ya)，至(zhi)少应(ying)该为主(zhu)绕组的3倍，需求留意的是，主(zhu)绕组的电压(ya)(ya)(ya)指(zhi)的是图(tu)(tu)2.6中的N2或者N3，而(er)(er)不是二者相加(jia)。详细而(er)(er)言，图(tu)(tu)中为10.5V，因而(er)(er)Q1、Q2的电压(ya)(ya)(ya)规格(ge)至(zhi)少为31.5V，思索(suo)到10%的动摇和(he)1.5倍的保险系数，则电压(ya)(ya)(ya)规格(ge)不应(ying)该低于31.5 X 1.1X 1.5＝52V。图(tu)(tu)中的2SK2313的电压(ya)(ya)(ya)规格(ge)为60v，契合请求。

其次，依据(ju)普通(tong)(tong)经历，电(dian)压规格超越200V的(de)(de)VMOS，饱和导(dao)通(tong)(tong)电(dian)阻的(de)(de)优势就不明显了，而本(ben)钱却比二极管高(gao)得多，电(dian)路也复杂。因而，用作同步整流时，主绕(rao)组(zu)的(de)(de)最(zui)高(gao)电(dian)压不应该高(gao)于40V。

2、电流规格(In)

这(zhei)个(ge)(ge)问题主要与最(zui)大耗散功率(lv)有(you)关，由于计算办(ban)法复杂并且需求实验停止(zhi)验证，因(yin)而也能(neng)够直接(jie)用(yong)理论办(ban)法进行(xing)肯定，即在实践的(de)工作环(huan)境中，依照最(zui)极(ji)端的(de)最(zui)高(gao)环(huan)境温度，比(bi)方(fang)夏天比(bi)拟(ni)热的(de)温度，如(ru)35℃，依据实践所(suo)需求的(de)工作电流(liu)，接(jie)上适宜的(de)假负(fu)载，连续工作2小时左右，假如(ru)MOS管散热片(TAB)不烫手，就根(gen)本上能(neng)够运用(yong)。这(zhei)个(ge)(ge)办(ban)法固然(ran)粗略，但(dan)是很(hen)简单适用(yong)。

3、mos饱和导通电阻(RDS（ON）)

越小越好，典型值最好小于10mQ，这(zhei)个(ge)数值以从技术手册上查到。

4、MOS管导通条件

导通(tong)与截止由栅(zha)(zha)源电(dian)压(ya)来(lai)控制(zhi)，对于增强(qiang)(qiang)型(xing)场效应(ying)管来(lai)说，N沟道的(de)(de)管子(zi)(zi)(zi)加正向(xiang)电(dian)压(ya)即导通(tong)，P沟道的(de)(de)管子(zi)(zi)(zi)则加反向(xiang)电(dian)压(ya)。一般2V～4V就可以了(le)。但是，场效应(ying)管分为(wei)增强(qiang)(qiang)型(xing)（常(chang)开型(xing)）和耗(hao)尽型(xing)（常(chang)闭型(xing)），增强(qiang)(qiang)型(xing)的(de)(de)管子(zi)(zi)(zi)是需(xu)要(yao)加电(dian)压(ya)才(cai)能导通(tong)的(de)(de)，而耗(hao)尽型(xing)管子(zi)(zi)(zi)本来(lai)就处于导通(tong)状态，加栅(zha)(zha)源电(dian)压(ya)是为(wei)了(le)使其(qi)截止。

开关只有(you)两(liang)种状(zhuang)态通和(he)断，三极管和(he)场效应管工作(zuo)有(you)三种状(zhuang)态：

1、截止；

2、线性放大；

3、饱和（基极(ji)电流继续增(zeng)加(jia)而集电极(ji)电流不再(zai)增(zeng)加(jia)）；

使晶(jing)体管(guan)只工作在(zai)1和(he)(he)(he)3状(zhuang)态(tai)的(de)(de)电(dian)(dian)(dian)路称(cheng)之为开(kai)关电(dian)(dian)(dian)路，一般以(yi)晶(jing)体管(guan)截止，集电(dian)(dian)(dian)极(ji)不吸收电(dian)(dian)(dian)流(liu)表(biao)示(shi)关；以(yi)晶(jing)体管(guan)饱和(he)(he)(he)，发射(she)极(ji)和(he)(he)(he)集电(dian)(dian)(dian)极(ji)之间(jian)的(de)(de)电(dian)(dian)(dian)压差接近于(yu)(yu)0V时表(biao)示(shi)开(kai)。开(kai)关电(dian)(dian)(dian)路用于(yu)(yu)数(shu)字电(dian)(dian)(dian)路时，输出电(dian)(dian)(dian)位(wei)接近0V时表(biao)示(shi)0，输出电(dian)(dian)(dian)位(wei)接近电(dian)(dian)(dian)源(yuan)电(dian)(dian)(dian)压时表(biao)示(shi)1。所以(yi)数(shu)字集成电(dian)(dian)(dian)路内部(bu)的(de)(de)晶(jing)体管(guan)都(dou)工作在(zai)开(kai)关状(zhuang)态(tai)。 场(chang)效应(ying)管(guan)按(an)沟道分(fen)可分(fen)为Ｎ沟道和(he)(he)(he)Ｐ沟道管(guan)（在(zai)符号图中可看(kan)到中间(jian)的(de)(de)箭头方向不一样）。

按(an)材料分可(ke)(ke)分为(wei)结型管(guan)(guan)(guan)和(he)绝缘栅(zha)型管(guan)(guan)(guan)，绝缘栅(zha)型又分为(wei)耗尽型和(he)增强(qiang)型，一般主板上大多是(shi)绝缘栅(zha)型管(guan)(guan)(guan)简(jian)称(cheng)(cheng)MOS管(guan)(guan)(guan)，并且大多采用增强(qiang)型的Ｎ沟(gou)道(dao)，其次(ci)是(shi)增强(qiang)型的Ｐ沟(gou)道(dao)，结型管(guan)(guan)(guan)和(he)耗尽型管(guan)(guan)(guan)几乎(hu)不(bu)用。场效(xiao)(xiao)应晶(jing)体(ti)(ti)管(guan)(guan)(guan)（Field Effect Transistor缩写(FET)）简(jian)称(cheng)(cheng)场效(xiao)(xiao)应管(guan)(guan)(guan).由多数(shu)载流(liu)子(zi)参与导电(dian)(dian),也(ye)称(cheng)(cheng)为(wei)单(dan)极型晶(jing)体(ti)(ti)管(guan)(guan)(guan).它属于电(dian)(dian)压控制型半导体(ti)(ti)器件(jian).场效(xiao)(xiao)应管(guan)(guan)(guan)是(shi)利用多数(shu)载流(liu)子(zi)导电(dian)(dian),所以(yi)称(cheng)(cheng)之为(wei)单(dan)极型器件(jian),而晶(jing)体(ti)(ti)管(guan)(guan)(guan)是(shi)即有多数(shu)载流(liu)子(zi),也(ye)利用少数(shu)载流(liu)子(zi)导电(dian)(dian),被称(cheng)(cheng)之为(wei)双极型器件(jian).有些场效(xiao)(xiao)应管(guan)(guan)(guan)的源极和(he)漏(lou)极可(ke)(ke)以(yi)互(hu)换(huan)使用,栅(zha)压也(ye)可(ke)(ke)正可(ke)(ke)负,灵活性比晶(jing)体(ti)(ti)管(guan)(guan)(guan)好。

5、MOS管导通过程

导通时序可分为to~t1、t1~t2、 t2~t3 、t3~t4四个(ge)(ge)时间段，这四个(ge)(ge)时间段有不(bu)同的等效电路。

1）t0-t1：C GS1 开始充电(dian)，栅(zha)极(ji)电(dian)压还没有到达(da)V GS（th），导(dao)电(dian)沟道没有形成，MOSFET仍处于关闭状态。

2）[t1-t2]区(qu)间(jian), GS间(jian)电(dian)压到达Vgs（th），DS间(jian)导电(dian)沟道开(kai)始形成，MOSFET开(kai)启，DS电(dian)流增(zeng)加到ID, Cgs2 迅速充(chong)电(dian)，Vgs由(you)Vgs（th）指数增(zeng)长到Va。

3）[t2-t3]区间(jian),MOSFET的DS电(dian)压(ya)(ya)降至与Vgs相同,产生Millier效(xiao)应，Cgd电(dian)容(rong)大(da)(da)大(da)(da)增(zeng)加,栅极电(dian)流(liu)持(chi)续流(liu)过，由于C gd 电(dian)容(rong)急剧增(zeng)大(da)(da)，抑(yi)制了栅极电(dian)压(ya)(ya)对Cgs 的充电(dian),从而(er)使(shi)得Vgs 近乎水(shui)平状态，Cgd 电(dian)容(rong)上电(dian)压(ya)(ya)增(zeng)加,而(er)DS电(dian)容(rong)上的电(dian)压(ya)(ya)继(ji)续减小(xiao)。

4）[t3-t4]区间,至t3时刻,MOSFET的(de)DS电(dian)(dian)(dian)压(ya)降至饱和导通时的(de)电(dian)(dian)(dian)压(ya),Millier效(xiao)应影响(xiang)变(bian)小(xiao)，Cgd 电(dian)(dian)(dian)容变(bian)小(xiao)并和Cgs 电(dian)(dian)(dian)容一起由外部驱动(dong)电(dian)(dian)(dian)压(ya)充电(dian)(dian)(dian), Cgs 电(dian)(dian)(dian)容的(de)电(dian)(dian)(dian)压(ya)上升,至t4时刻为止.此时C gs 电(dian)(dian)(dian)容电(dian)(dian)(dian)压(ya)已达(da)稳态,DS间电(dian)(dian)(dian)压(ya)也达(da)最小(xiao)，MOSFET完全开(kai)启。

联系(xi)方式：邹先生（MOS管原厂家）

联系电(dian)话：0755-83888366-8022

手机：18123972950

QQ：2880195519

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