晶(jing)体(ti)管(guan)工(gong)作原理(li)(li) 晶(jing)体(ti)管(guan)分类(lei)及介绍 解析全(quan)面晶(jing)体(ti)管(guan)工(gong)作原理(li)(li)大全(quan)-KIA MOS管(guan)
信(xin)息来源:本站(zhan) 日期:2017-05-25
电力晶体管(guan)按英(ying)文Giant Transistor直(zhi)译(yi)为(wei)巨型(xing)晶体管(guan),是一种耐高(gao)电压、大电流(liu)的双极结型(xing)晶体管(guan)(Bipolar Junction Transistor—BJT),所以有时也称为(wei)Power BJT;其特性有:耐压高(gao),电流(liu)大,开关特性好,但驱动电路复(fu)杂,驱动功率大;GTR和普通双极结型(xing)晶体管(guan)的工作原理(li)是一样的。
光(guang)(guang)晶体(ti)(ti)管(phototransistor)由(you)双极(ji)(ji)型(xing)晶体(ti)(ti)管或场效应(ying)晶体(ti)(ti)管等三端(duan)器(qi)(qi)(qi)件(jian)构(gou)(gou)成的光(guang)(guang)电(dian)(dian)器(qi)(qi)(qi)件(jian)。光(guang)(guang)在这类器(qi)(qi)(qi)件(jian)的有源(yuan)区内被吸(xi)收,产(chan)生(sheng)光(guang)(guang)生(sheng)载流子,通过内部电(dian)(dian)放大(da)(da)(da)(da)机构(gou)(gou),产(chan)生(sheng)光(guang)(guang)电(dian)(dian)流增益。光(guang)(guang)晶体(ti)(ti)管三端(duan)工作,故容易实现(xian)电(dian)(dian)控或电(dian)(dian)同步(bu)。光(guang)(guang)晶体(ti)(ti)管所用(yong)(yong)材(cai)料通常(chang)(chang)是砷化镓(GaAs),主要分(fen)为双极(ji)(ji)型(xing)光(guang)(guang)晶体(ti)(ti)管、场效应(ying)光(guang)(guang)晶体(ti)(ti)管及其(qi)相关(guan)器(qi)(qi)(qi)件(jian)。双极(ji)(ji)型(xing)光(guang)(guang)晶体(ti)(ti)管通常(chang)(chang)增益很高(gao),但速(su)(su)度不太快,对于(yu)GaAs-GaAlAs,放大(da)(da)(da)(da)系数(shu)可(ke)大(da)(da)(da)(da)于(yu)1000,响应(ying)时间大(da)(da)(da)(da)于(yu)纳秒,常(chang)(chang)用(yong)(yong)于(yu)光(guang)(guang)探测(ce)器(qi)(qi)(qi),也可(ke)用(yong)(yong)于(yu)光(guang)(guang)放大(da)(da)(da)(da)。场效应(ying)光(guang)(guang)晶体(ti)(ti)管响应(ying)速(su)(su)度快(约为50皮秒),但缺(que)点(dian)是光(guang)(guang)敏(min)面积小,增益小(放大(da)(da)(da)(da)系数(shu)可(ke)大(da)(da)(da)(da)于(yu)10),常(chang)(chang)用(yong)(yong)作极(ji)(ji)高(gao)速(su)(su)光(guang)(guang)探测(ce)器(qi)(qi)(qi)。与(yu)此相关(guan)还有许多(duo)其(qi)他(ta)平(ping)面型(xing)光(guang)(guang)电(dian)(dian)器(qi)(qi)(qi)件(jian),其(qi)特点(dian)均是速(su)(su)度快(响应(ying)时间几十皮秒)、适(shi)于(yu)集(ji)成。这类器(qi)(qi)(qi)件(jian)可(ke)望在光(guang)(guang)电(dian)(dian)集(ji)成中得到应(ying)用(yong)(yong)。
双极晶(jing)体管(bipolar transistor)指(zhi)在音(yin)频电路中使用得非常(chang)普遍的(de)(de)一种晶(jing)体管。双极则源于电流(liu)系(xi)在两种半导体材料中流(liu)过的(de)(de)关系(xi)。双极晶(jing)体管根据工作电压的(de)(de)极性而可分为NPN型或PNP型。
“双极(ji)”的(de)含义是指其(qi)工作时(shi)电(dian)(dian)子和(he)空穴这两种(zhong)载(zai)流(liu)子都同(tong)时(shi)参与运动(dong)。双极(ji)结(jie)(jie)型晶体管(guan)(guan)(Bipolar Junction Transistor—BJT)又称为半导体三极(ji)管(guan)(guan),它是通过(guo)一定的(de)工艺将两个(ge)PN结(jie)(jie)结(jie)(jie)合在(zai)一起的(de)器件,有(you)PNP和(he)NPN两种(zhong)组(zu)合结(jie)(jie)构;外部引(yin)出(chu)三个(ge)极(ji):集(ji)电(dian)(dian)极(ji),发(fa)(fa)射极(ji)和(he)基(ji)极(ji),集(ji)电(dian)(dian)极(ji)从集(ji)电(dian)(dian)区引(yin)出(chu),发(fa)(fa)射极(ji)从发(fa)(fa)射区引(yin)出(chu),基(ji)极(ji)从基(ji)区引(yin)出(chu)(基(ji)区在(zai)中间);BJT有(you)放(fang)大作用(yong),重要(yao)依靠它的(de)发(fa)(fa)射极(ji)电(dian)(dian)流(liu)能够通过(guo)基(ji)区传输到达集(ji)电(dian)(dian)区而实现(xian)的(de),为了保证(zheng)这一传输过(guo)程,一方面(mian)要(yao)满足内部条件,即要(yao)求发(fa)(fa)射区杂质浓度(du)要(yao)远(yuan)大于基(ji)区杂质浓度(du),同(tong)时(shi)基(ji)区厚度(du)要(yao)很(hen)(hen)小(xiao),另一方面(mian)要(yao)满足外部条件,即发(fa)(fa)射结(jie)(jie)要(yao)正(zheng)(zheng)向偏置(zhi)(加正(zheng)(zheng)向电(dian)(dian)压)、集(ji)电(dian)(dian)结(jie)(jie)要(yao)反偏置(zhi);BJT种(zhong)类(lei)很(hen)(hen)多(duo),按照频率(lv)分(fen),有(you)高频管(guan)(guan),低(di)频管(guan)(guan),按照功率(lv)分(fen),有(you)小(xiao)、中、大功率(lv)管(guan)(guan),按照半导体材料分(fen),有(you)硅管(guan)(guan)和(he)锗(zhe)管(guan)(guan)等;其(qi)构成的(de)放(fang)大电(dian)(dian)路形式有(you):共发(fa)(fa)射极(ji)、共基(ji)极(ji)和(he)共集(ji)电(dian)(dian)极(ji)放(fang)大电(dian)(dian)路。
“场效(xiao)应(ying)”的含(han)义是这种晶(jing)体(ti)(ti)管(guan)的工作(zuo)原(yuan)理(li)是基于半(ban)导(dao)(dao)体(ti)(ti)的电场效(xiao)应(ying)的。场效(xiao)应(ying)晶(jing)体(ti)(ti)管(guan)(field effect transistor)利用(yong)场效(xiao)应(ying)原(yuan)理(li)工作(zuo)的晶(jing)体(ti)(ti)管(guan),英(ying)文简称FET。场效(xiao)应(ying)晶(jing)体(ti)(ti)管(guan)又包含(han)两种主要类型(xing):结(jie)型(xing)场效(xiao)应(ying)管(guan)(Junction FET,缩(suo)写为JFET)和金属-氧化(hua)物半(ban)导(dao)(dao)体(ti)(ti)场效(xiao)应(ying)管(guan)(Metal-Oxide Semiconductor FET,缩(suo)写为MOS-FET)。与BJT不同(tong)的是,FET只由一种载流子(多数载流子)参与导(dao)(dao)电,因(yin)此也(ye)称为单极型(xing)晶(jing)体(ti)(ti)管(guan)。它属于电压控制(zhi)型(xing)半(ban)导(dao)(dao)体(ti)(ti)器件(jian),具有输入电阻高、噪声小、功耗低、动态(tai)范围大、易于集成、没有二次击(ji)穿现象、安全(quan)工作(zuo)区域宽等优(you)点。
场(chang)效应(ying)(ying)(ying)(ying)就是(shi)(shi)改变(bian)外加垂直于(yu)半(ban)导(dao)体(ti)(ti)(ti)表面上电(dian)(dian)场(chang)的(de)方向或(huo)(huo)大小,以(yi)控制半(ban)导(dao)体(ti)(ti)(ti)导(dao)电(dian)(dian)层(沟道)中(zhong)多数(shu)载(zai)流(liu)子(zi)的(de)密度或(huo)(huo)类(lei)(lei)型。它是(shi)(shi)由(you)(you)电(dian)(dian)压调制沟道中(zhong)的(de)电(dian)(dian)流(liu),其工(gong)作电(dian)(dian)流(liu)是(shi)(shi)由(you)(you)半(ban)导(dao)体(ti)(ti)(ti)中(zhong)的(de)多数(shu)载(zai)流(liu)子(zi)输运。这类(lei)(lei)只有一种极(ji)(ji)性载(zai)流(liu)子(zi)参加导(dao)电(dian)(dian)的(de)晶(jing)体(ti)(ti)(ti)管(guan)(guan)又称单极(ji)(ji)型晶(jing)体(ti)(ti)(ti)管(guan)(guan)。与双(shuang)极(ji)(ji)型晶(jing)体(ti)(ti)(ti)管(guan)(guan)相比,场(chang)效应(ying)(ying)(ying)(ying)晶(jing)体(ti)(ti)(ti)管(guan)(guan)具(ju)有输入(ru)阻抗高、噪声小、极(ji)(ji)限(xian)频率高、功耗小,制造(zao)工(gong)艺简(jian)单、温(wen)度特(te)性好等特(te)点,广泛应(ying)(ying)(ying)(ying)用于(yu)各种放大电(dian)(dian)路、数(shu)字电(dian)(dian)路和(he)微波电(dian)(dian)路等。以(yi)硅材(cai)料为基(ji)础的(de)金属(shu)0-氧(yang)化(hua)物-半(ban)导(dao)体(ti)(ti)(ti)场(chang)效应(ying)(ying)(ying)(ying)管(guan)(guan)(MOSFET)和(he)以(yi)砷化(hua)镓材(cai)料为基(ji)础的(de)肖特(te)基(ji)势垒栅场(chang)效应(ying)(ying)(ying)(ying)管(guan)(guan)(MESFET )是(shi)(shi)两种最重要的(de)场(chang)效应(ying)(ying)(ying)(ying)晶(jing)体(ti)(ti)(ti)管(guan)(guan),分别为MOS大规模集成(cheng)电(dian)(dian)路和(he)MES超高速(su)集成(cheng)电(dian)(dian)路的(de)基(ji)础器(qi)件。
静电(dian)感应(ying)(ying)晶(jing)体(ti)管SIT(StaticInductionTransistor)诞生于1970年,实际上是一(yi)种结(jie)型场(chang)效应(ying)(ying)晶(jing)体(ti)管。将用于信息(xi)处理的(de)(de)小功率(lv)SIT器件的(de)(de)横(heng)向(xiang)导(dao)电(dian)结(jie)构(gou)改(gai)为(wei)垂(chui)直(zhi)导(dao)电(dian)结(jie)构(gou),即可制(zhi)成(cheng)大(da)功率(lv)的(de)(de)SIT器件。SIT是一(yi)种多子导(dao)电(dian)的(de)(de)器件,其工作频(pin)率(lv)与(yu)电(dian)力(li)(li)MOSFET相当,甚(shen)至(zhi)超过电(dian)力(li)(li)MOSFET,而功率(lv)容量也比电(dian)力(li)(li)MOSFET大(da),因(yin)而适用于高频(pin)大(da)功率(lv)场(chang)合(he),目前已在(zai)雷达通信设备、超声波功率(lv)放大(da)、脉冲功率(lv)放大(da)和高频(pin)感应(ying)(ying)加热(re)等(deng)某些专业领域获得了较多的(de)(de)应(ying)(ying)用。
但是SIT在栅(zha)极不加(jia)任何信号时是导通的,栅(zha)极加(jia)负(fu)偏(pian)压时关断,这(zhei)被称为(wei)正(zheng)常导通型器(qi)件,使(shi)用不太方(fang)便。此外(wai),SIT通态电阻较大(da),使(shi)得通态损耗也(ye)大(da),因而SIT还未(wei)在大(da)多数电力(li)电子设备中得到广泛应用。
用一(yi)个(ge)或者(zhe)少量电(dian)子(zi)就能记(ji)录(lu)信号的晶体(ti)管。随着半导体(ti)刻(ke)蚀技(ji)术和工艺的发(fa)展(zhan)(zhan),大(da)规模(mo)集(ji)(ji)成(cheng)(cheng)电(dian)路的集(ji)(ji)成(cheng)(cheng)度越(yue)来(lai)越(yue)高。以动(dong)态(tai)随机(ji)存(cun)储(chu)器(DRAM)为(wei)例(li),它(ta)的集(ji)(ji)成(cheng)(cheng)度差不(bu)多以每两年(nian)增加四(si)倍的速度发(fa)展(zhan)(zhan),预计单(dan)(dan)电(dian)子(zi)晶体(ti)管将(jiang)是最终(zhong)的目(mu)标。目(mu)前一(yi)般的存(cun)储(chu)器每个(ge)存(cun)储(chu)元包(bao)含了20万个(ge)电(dian)子(zi),而单(dan)(dan)电(dian)子(zi)晶体(ti)管每个(ge)存(cun)储(chu)元只包(bao)含了一(yi)个(ge)或少量电(dian)子(zi),因此它(ta)将(jiang)大(da)大(da)降低功(gong)耗,提高集(ji)(ji)成(cheng)(cheng)电(dian)路的集(ji)(ji)成(cheng)(cheng)度。
1989年斯各(ge)特(J.H.F.Scott-Thomas)等(deng)人在(zai)(zai)实(shi)(shi)(shi)验上发现(xian)了(le)库仑阻(zu)塞现(xian)象。在(zai)(zai)调(diao)制掺(chan)杂异质结界(jie)(jie)面形成的(de)(de)(de)二维(wei)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)子(zi)(zi)(zi)(zi)(zi)气(qi)上面,制作(zuo)一(yi)个面积很小的(de)(de)(de)金(jin)属(shu)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)极(ji),使(shi)得在(zai)(zai)二维(wei)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)子(zi)(zi)(zi)(zi)(zi)气(qi)中(zhong)形成一(yi)个量子(zi)(zi)(zi)(zi)(zi)点,它只能(neng)容纳(na)少量的(de)(de)(de)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)子(zi)(zi)(zi)(zi)(zi),也就(jiu)是(shi)它的(de)(de)(de)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)容很小,小于(yu)一(yi)个F(10~15法拉)。当外加电(dian)(dian)(dian)(dian)(dian)(dian)(dian)压时,如果(guo)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)压变(bian)(bian)化(hua)(hua)引起量子(zi)(zi)(zi)(zi)(zi)点中(zhong)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷变(bian)(bian)化(hua)(hua)量不到一(yi)个电(dian)(dian)(dian)(dian)(dian)(dian)(dian)子(zi)(zi)(zi)(zi)(zi)的(de)(de)(de)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷,则将没有(you)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)通(tong)过(guo)(guo)。直(zhi)到电(dian)(dian)(dian)(dian)(dian)(dian)(dian)压增大(da)到能(neng)引起一(yi)个电(dian)(dian)(dian)(dian)(dian)(dian)(dian)子(zi)(zi)(zi)(zi)(zi)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷的(de)(de)(de)变(bian)(bian)化(hua)(hua)时,才有(you)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)通(tong)过(guo)(guo)。因此(ci)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)-电(dian)(dian)(dian)(dian)(dian)(dian)(dian)压关系不是(shi)通(tong)常的(de)(de)(de)直(zhi)线关系,而是(shi)台阶形的(de)(de)(de)。这个实(shi)(shi)(shi)验在(zai)(zai)历(li)史上第一(yi)次实(shi)(shi)(shi)现(xian)了(le)用(yong)人工(gong)控制一(yi)个电(dian)(dian)(dian)(dian)(dian)(dian)(dian)子(zi)(zi)(zi)(zi)(zi)的(de)(de)(de)运动,为(wei)制造单(dan)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)子(zi)(zi)(zi)(zi)(zi)晶(jing)体管(guan)提供了(le)实(shi)(shi)(shi)验依据(ju)。为(wei)了(le)提高单(dan)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)子(zi)(zi)(zi)(zi)(zi)晶(jing)体管(guan)的(de)(de)(de)工(gong)作(zuo)温度,必须使(shi)量子(zi)(zi)(zi)(zi)(zi)点的(de)(de)(de)尺寸小于(yu)10纳(na)米,目前世(shi)界(jie)(jie)各(ge)实(shi)(shi)(shi)验室(shi)都在(zai)(zai)想各(ge)种(zhong)办法解决这个问题。有(you)些实(shi)(shi)(shi)验室(shi)宣称(cheng)已(yi)制出室(shi)温下工(gong)作(zuo)的(de)(de)(de)单(dan)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)子(zi)(zi)(zi)(zi)(zi)晶(jing)体管(guan),观察到由电(dian)(dian)(dian)(dian)(dian)(dian)(dian)子(zi)(zi)(zi)(zi)(zi)输运形成的(de)(de)(de)台阶型电(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)——电(dian)(dian)(dian)(dian)(dian)(dian)(dian)压曲(qu)线,但离实(shi)(shi)(shi)用(yong)还有(you)相当的(de)(de)(de)距(ju)离。
绝缘栅(zha)双极晶(jing)体(ti)管(Insulate-GateBipolarTransistor—IGBT)综合了(le)电力(li)晶(jing)体(ti)管(GiantTransistor—GTR)和(he)电力(li)场(chang)效应晶(jing)体(ti)管(PowerMOSFET)的(de)优(you)点,具有良好的(de)特性(xing),应用(yong)领域很广(guang)泛;IGBT也(ye)是三端器件:栅(zha)极,集电极和(he)发射极。
功率开(kai)关管的(de)种类很多,如巨型(xing)晶(jing)体(ti)(ti)管GTR、快速晶(jing)闸(zha)管SCR、门(men)极(ji)可关断晶(jing)闸(zha)管GTO、功率(lv)场效(xiao)应晶(jing)体(ti)(ti)管P- MOSFET和绝缘(yuan)栅双极(ji)型(xing)晶(jing)体(ti)(ti)管IGBT等。其中(zhong),开(kai)关电源中(zhong)经(jing)常使用的(de)是P - MOSFET和IGBT。
选择功率(lv)(lv)开(kai)关(guan)管时(shi),应根据变换器类(lei)型、功率(lv)(lv)和(he)可靠性(xing)等性(xing)能,确定(ding)功率(lv)(lv)开(kai)关(guan)管的耐(nai)压值和(he)导通电流(liu)等参数。
双极结型晶体管(guan)( BJT)是一种(zhong)舣极型半导体器(qi)件,其中(zhong)大容(rong)量(liang)的(de)双极结型(xing)晶(jing)体管义(yi)称(cheng)巨型(xing)晶(jing)体管( GTR),其内部有(you)电(dian)子和(he)空穴两(liang)种(zhong)载流子。根据半导(dao)体类(lei)型(xing)的(de)不同,BJT可以分(fen)为(wei)NPN型(xing)和(he)PNP型(xing)两(liang)种(zhong),其中(zhong)硅功(gong)率(lv)晶(jing)体管多为(wei)NPN型(xing)。在(zai)(zai)开(kai)(kai)关(guan)电(dian)源中(zhong)1,BJT工(gong)作(zuo)在(zai)(zai)开(kai)(kai)关(guan)状态(tai),即工(gong)作(zuo)在(zai)(zai)截(jie)止区或(huo)饱和(he)区。BJT的(de)开(kai)(kai)关(guan)时(shi)(shi)间(jian)对它的(de)应用有(you)较大的(de)影n向,因此选(xuan)用BJT时(shi)(shi),应注(zhu)意其开(kai)(kai)关(guan)频率(lv)。为(wei)了使BJT快速导(dao)通,缩(suo)(suo)短(duan)(duan)开(kai)(kai)通时(shi)(shi)间(jian)toff驱动电(dian)流必须具(ju)有(you)—定幅(fu)值(zhi),且前(qian)(qian)沿足够(gou)陡峭并有(you)。定过冲(chong)的(de)止向驱动电(dian)流为(wei)加(jia)速BJT关(guan)断,缩(suo)(suo)短(duan)(duan)关(guan)断时(shi)(shi)间(jian)TOFF在(zai)(zai)关(guan)断前(qian)(qian)使BJt'处于临界饱和(he)状态(tai),基极反偏电(dian)流幅(fu)值(zhi)足够(gou)大,并且加(jia)反向截(jie)止电(dian)压。
此外,BJT的(de)工作点(dian)是(shi)随电(dian)(dian)压(ya)(ya)和电(dian)(dian)流的(de)不同而变化的(de),而一般厂家给出的(de)参(can)数是(shi)在特定条件且(qie)环境(jing)温(wen)度为+25度数值。当环境(jing)温(wen)度高(gao)于(yu)+25℃时(shi)(shi)(shi),BJT的(de)功率(lv)应(ying)适当降低(di)。增大电(dian)(dian)压(ya)(ya)和电(dian)(dian)流余(yu)量(liang),同时(shi)(shi)(shi)改(gai)善散(san)热(re)条件,可以(yi)提高(gao)BJT的(de)可靠件:BJT应(ying)尽(jin)量(liang)避(bi)免(mian)靠近发热(re)元件,以(yi)保证(zheng)管壳(qiao)散(san)热(re)良好(hao)。当BJT的(de)耗(hao)散(san)功率(lv)大于(yu)SW时(shi)(shi)(shi),应(ying)加(jia)散(san)热(re)器。焊接(jie)BJT时(shi)(shi)(shi),应(ying)采用熔点(dian)不超(chao)过150℃的(de)低(di)熔点(dian)焊锡,且(qie)电(dian)(dian)烙铁以(yi)60W以(yi)卜为宜,焊接(jie)时(shi)(shi)(shi)间不超(chao)过5,。为防止BJT(MOS管击穿(chuan))二次(ci)击穿(chuan),应尽量避免采用电抗成分过大(da)的负载,并合理选择工作(zuo)点及工作(zuo)状态,使之不超(chao)过BJT的安全工作(zuo)区.
参数
晶体(ti)管的(de)主要参(can)数(shu)(shu)有电(dian)流(liu)放大(da)(da)系数(shu)(shu)、耗(hao)散功率、频(pin)率特性、集电(dian)极最大(da)(da)电(dian)流(liu)、最大(da)(da)反向(xiang)电(dian)压、反向(xiang)电(dian)流(liu)等。
放大系数
直流(liu)电流(liu)放大(da)系数也称(cheng)静态(tai)电流(liu)放大(da)系数或(huo)直流(liu)放大(da)倍数,是(shi)指(zhi)在静态(tai)无变化信号输入时,晶体管(guan)集电极电流(liu)IC与基极电流(liu)IB的(de)比值,一般用hFE或(huo)β表示。
交流放大倍数
交(jiao)流(liu)(liu)放大倍数(shu)(shu),也即交(jiao)流(liu)(liu)电流(liu)(liu)放大系(xi)数(shu)(shu)、动态(tai)(tai)电流(liu)(liu)放大系(xi)数(shu)(shu),是指在交(jiao)流(liu)(liu)状态(tai)(tai)下,晶体(ti)管集电极电流(liu)(liu)变化(hua)量(liang)△IC与基极电流(liu)(liu)变化(hua)量(liang)△IB的比值(zhi),一般用hfe或(huo)β表示。hFE或(huo)β既有(you)区(qu)别又关系(xi)密切,两个参数(shu)(shu)值(zhi)在低频(pin)时较接近(jin),在高(gao)频(pin)时有(you)一些差异。
耗散功率
耗(hao)(hao)(hao)散(san)功(gong)(gong)率(lv)(lv)(lv)(lv)(lv)(lv)也称(cheng)集(ji)电(dian)极(ji)最大允(yun)许(xu)(xu)耗(hao)(hao)(hao)散(san)功(gong)(gong)率(lv)(lv)(lv)(lv)(lv)(lv)PCM,是指晶(jing)体(ti)管参(can)数变(bian)化不(bu)超过规定允(yun)许(xu)(xu)值时的(de)(de)最大集(ji)电(dian)极(ji)耗(hao)(hao)(hao)散(san)功(gong)(gong)率(lv)(lv)(lv)(lv)(lv)(lv)。耗(hao)(hao)(hao)散(san)功(gong)(gong)率(lv)(lv)(lv)(lv)(lv)(lv)与晶(jing)体(ti)管的(de)(de)最高允(yun)许(xu)(xu)结温和(he)集(ji)电(dian)极(ji)最大电(dian)流有密(mi)切关系。晶(jing)体(ti)管在使(shi)用时,其实际(ji)功(gong)(gong)耗(hao)(hao)(hao)不(bu)允(yun)许(xu)(xu)超过PCM值,否(fou)则会造成(cheng)晶(jing)体(ti)管因过载而损坏(huai)。通(tong)常将耗(hao)(hao)(hao)散(san)功(gong)(gong)率(lv)(lv)(lv)(lv)(lv)(lv)PCM小于(yu)(yu)(yu)1W的(de)(de)晶(jing)体(ti)管称(cheng)为(wei)小功(gong)(gong)率(lv)(lv)(lv)(lv)(lv)(lv)晶(jing)体(ti)管,PCM等于(yu)(yu)(yu)或(huo)大于(yu)(yu)(yu)1W、小于(yu)(yu)(yu)5W的(de)(de)晶(jing)体(ti)管被称(cheng)为(wei)中功(gong)(gong)率(lv)(lv)(lv)(lv)(lv)(lv)晶(jing)体(ti)管,将PCM等于(yu)(yu)(yu)或(huo)大于(yu)(yu)(yu)5W的(de)(de)晶(jing)体(ti)管称(cheng)为(wei)大功(gong)(gong)率(lv)(lv)(lv)(lv)(lv)(lv)晶(jing)体(ti)管。
最高频率fM
最高(gao)振荡频(pin)(pin)(pin)率(lv)(lv)是指晶(jing)体管的(de)功率(lv)(lv)增益降(jiang)为1时(shi)所对应的(de)频(pin)(pin)(pin)率(lv)(lv)。通(tong)常,高(gao)频(pin)(pin)(pin)晶(jing)体管的(de)最高(gao)振荡频(pin)(pin)(pin)率(lv)(lv)低(di)(di)于共(gong)基(ji)极截止(zhi)(zhi)频(pin)(pin)(pin)率(lv)(lv)fα,而特(te)征频(pin)(pin)(pin)率(lv)(lv)fT则高(gao)于共(gong)基(ji)极截止(zhi)(zhi)频(pin)(pin)(pin)率(lv)(lv)fα、低(di)(di)于共(gong)集电极截止(zhi)(zhi)频(pin)(pin)(pin)率(lv)(lv)fβ。
最大电流
集电极(ji)(ji)最大电流(ICM)是(shi)指(zhi)晶体管集电极(ji)(ji)所(suo)允(yun)许(xu)通过的(de)最大电流。当晶体管的(de)集电极(ji)(ji)电流IC超过ICM时,晶体管的(de)β值等参数将发(fa)生明显变(bian)化,影响(xiang)其正(zheng)常工作,甚至还会(hui)损坏。
最大反向电压
最(zui)大反向电(dian)压(ya)是指晶(jing)体(ti)管在工作(zuo)时所允许施加的(de)最(zui)高(gao)工作(zuo)电(dian)压(ya)。它包括(kuo)集电(dian)极(ji)—发射极(ji)反向击(ji)(ji)(ji)穿电(dian)压(ya)、集电(dian)极(ji)—基极(ji)反向击(ji)(ji)(ji)穿电(dian)压(ya)和发射极(ji)—基极(ji)反向击(ji)(ji)(ji)穿电(dian)压(ya)。
集电极——集电极反向击穿电压
该(gai)(gai)电(dian)压(ya)是指当晶(jing)体管基(ji)极(ji)开(kai)路时,其(qi)集电(dian)极(ji)与(yu)发(fa)射极(ji)之(zhi)间的最大允许反向电(dian)压(ya),一般用(yong)VCEO或BVCEO表示(shi)。基(ji)极(ji)—— 基(ji)极(ji)反向击(ji)穿电(dian)压(ya)该(gai)(gai)电(dian)压(ya)是指当晶(jing)体管发(fa)射极(ji)开(kai)路时,其(qi)集电(dian)极(ji)与(yu)基(ji)极(ji)之(zhi)间的最大允许反向电(dian)压(ya),用(yong)VCBO或BVCBO表示(shi)。
发射极——发射极反向击穿电压
该电压是(shi)指当晶(jing)体管的集电极开路时,其发射极与(yu)基极与(yu)之间的最大允许(xu)反向电压,用(yong)VEBO或(huo)BVEBO表示。
集电极——基极之间的反向电流ICBO
ICBO也(ye)称(cheng)集(ji)电(dian)结(jie)反向(xiang)漏电(dian)电(dian)流(liu),是(shi)指(zhi)当晶(jing)体管的发(fa)射极(ji)开路时,集(ji)电(dian)极(ji)与基极(ji)之间的反向(xiang)电(dian)流(liu)。ICBO对温度较敏感,该值越小,说(shuo)明晶(jing)体管的温度特性越好(hao)。
集电极——发射极之间的反向击穿电流ICEO
ICEO是(shi)指当晶体(ti)管的基极开(kai)路时(shi),其(qi)集(ji)电(dian)极与(yu)发射(she)极之间的反向漏电(dian)电(dian)流,也称穿透电(dian)流。此(ci)电(dian)流值越(yue)小,说明晶体(ti)管的性能越(yue)好
功率晶体管的性能。如
(1)开关晶(jing)体管有效芯片面积的(de)增加,
(2)技术上的简化,
(3)晶体管的复(fu)合(he)——达林顿,
(4)用(yong)于大功率开关(guan)的基极驱动技术(shu)的进步(bu)。
直接工(gong)作在(zai)整(zheng)流380V市电(dian)上的晶体管(guan)功率开(kai)关
晶体管(guan)复合(达林顿)和并联都是有效地增(zeng)加晶体管(guan)开关能(neng)力的方法
在这(zhei)样的(de)大功率电路中,存在的(de)主要(yao)问题是布线。很高的(de)开关速度能在很短的(de)连接(jie)线上产(chan)生(sheng)相当高的(de)干扰电压
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