IGBT 的(de)(de)(de)等效電(dian)(dian)路如圖1 所(suo)示。由(you)(you)圖1 可知,若在IGBT 的(de)(de)(de)柵極(ji)(ji)和發(fa)(fa)(fa)射(she)極(ji)(ji)之(zhi)間(jian)加上驅動(dong)(dong)正電(dian)(dian)壓(ya),則(ze)MOSFET 導通,這(zhe)樣(yang)PNP 晶體管(guan)(guan)的(de)(de)(de)集(ji)電(dian)(dian)極(ji)(ji)與(yu)(yu)基極(ji)(ji)之(zhi)間(jian)成低(di)阻(zu)狀(zhuang)態(tai)而使(shi)得晶體管(guan)(guan)導通;若IGBT 的(de)(de)(de)柵極(ji)(ji)和發(fa)(fa)(fa)射(she)極(ji)(ji)之(zhi)間(jian)電(dian)(dian)壓(ya)為(wei)0V,則(ze)MOSFET 截止(zhi),切斷PNP 晶體管(guan)(guan)基極(ji)(ji)電(dian)(dian)流(liu)的(de)(de)(de)供(gong)給,使(shi)得晶體管(guan)(guan)截止(zhi)。由(you)(you)此可知,IGBT 的(de)(de)(de)安(an)全可靠與(yu)(yu)否主(zhu)要由(you)(you)以下(xia)因素決定(ding):——IGBT 柵極(ji)(ji)與(yu)(yu)發(fa)(fa)(fa)射(she)極(ji)(ji)之(zhi)間(jian)的(de)(de)(de)電(dian)(dian)壓(ya);——IGBT 集(ji)電(dian)(dian)極(ji)(ji)與(yu)(yu)發(fa)(fa)(fa)射(she)極(ji)(ji)之(zhi)間(jian)的(de)(de)(de)電(dian)(dian)壓(ya);——流(liu)過(guo)IGBT 集(ji)電(dian)(dian)極(ji)(ji)-發(fa)(fa)(fa)射(she)極(ji)(ji)的(de)(de)(de)電(dian)(dian)流(liu);——IGBT 的(de)(de)(de)結溫。如果IGBT 柵極(ji)(ji)與(yu)(yu)發(fa)(fa)(fa)射(she)極(ji)(ji)之(zhi)間(jian)的(de)(de)(de)電(dian)(dian)壓(ya),即驅動(dong)(dong)電(dian)(dian)壓(ya)過(guo)低(di),則(ze)IGBT 不(bu)能穩(wen)定(ding)正常地(di)工(gong)作(zuo),如果過(guo)高(gao)超(chao)過(guo)柵極(ji)(ji)