模拟电子电路21.pptx

模拟电子电路21cc发射结发射结集电结集电结基区集电区发射区PbbNNPeeP+N+第1页/共37页的工作原理C 集电极1. BJT结构：由两个PN结和三个电极构成。有两个基本类型： NPN型 PNP型B 基极(1) NPN 型 三个区域： 发射区（E区）：高渗杂E 发射极基 区（B）区：薄、低渗杂集电区（C）区：渗杂适中C 集电极两个PN结： 发射结（BE结） 集电结（CB结）B 基极三个电极： 发射极（Emitter）:E(e) 基 极（Base）:B(b) 集电极（Collctor）:C(2) PNP型E 发射极返回第2页/共37页2. BJT三种基本组态 BJT三极管是三端器件，作为双口器件来使用(二极管是单口器件)。在接入工程电路的具体应用中，往往将其中的某一个电极作输入端，另一个电极作输出端，第三个电极作为输入、输出端口的公共端。BJT的接法又称为组态。三极管BJT作为双口器件接入电路的实用方式有三种： 共射极(CE) 组态 ,共基极(CB) 组态,共集电极(CC) 组态返回发射结发射结集电结集电结C 集电极C 集电极基区集电区发射区PNB 基极B 基极NPP+N+E 发射极E 发射极第3页/共37页1234573．BJT的偏置方式：①发射结正偏、集电结反偏，BJT处于放大状态②发射结反偏、集电结正偏，BJT处于反向应用状态，（一般不宜反向应用）③二个PN结均正偏，晶体管处于饱合状态④二个PN结均反偏，晶体管处于截至状态UCUBUEUCUBUEUBUE ,UB UCUBUE ,UB UCUCUBUE返回iEiB○○ iCiBiCiBiBiE○○ iEiEiCiC● ● ● ●● ● ● ●○○ ○○ ○○ ○○ c● ● ● ●● ● ● ●● ● ● ●● ● ● ●● ● ● ● ●● ● ● ● ●RC● ● ● ● ●● ● ● ● ●bRbECEBe第4页/共37页123457返回(1) 放大偏置时BJT载流子的传输过程： 将NPN BJT接成共射极型：以射极为输入和输出回路的公共端即： uBEUT , 发射结正偏 → 易于E区多子扩散 uCB＞0 ， 集中结反偏 → 易于B区少子漂移icpicn2icn1●●●● ● ● ● ●● ● ● ●● ● ● ●● ● ● ●● ● ● ● ●● ● ● ● ●● ● ● ●● ● ● ●ib1● ● ● ● ●● ● ● ● ●● ● ● ● ●● ● ● ● ●ien= icn1 + ib1仿真iEPieniE = ien + iEP ≈ ienICBO= icn2 + icpiC= ICBO + icn1 ;iB= ib1 + iEP-ICBOiE○○ iE○○ iE● ● ● ●● ● ● ●○○ ○○ ○○ ○○ c● ● ● ●● ● ● ●● ● ● ●● ● ● ●● ● ● ● ●● ● ● ● ●RC● ● ● ● ●● ● ● ● ●bRbECEBe第5页/共37页返回① 多子通过EB(发射)结注入B区icn1(iEP)注入E区的空穴是E区的非平衡少数载流子 ● ● ● ●● ● ● ●● ● ● ●● ● ● ●● ● ● ● ●● ● ● ● ●● ● ● ●● ● ● ●ib1● ● ● ● ●● ● ● ● ●● ● ● ● ●● ● ● ● ●iEPien123457○○ ○○ ● ● ● ●● ● ● ●○○ ○○ ○○ ○○ c● ● ● ●● ● ● ●● ● ● ●● ● ● ●● ● ● ● ●● ● ● ● ●RC● ● ● ● ●● ● ● ● ●bRbECEBe第6页/共37页② 由浓度差引起基区非平衡少数载流子的扩散与复合。icn1● ● ● ●● ● ● ●● ● ● ●● ● ● ●● ● ● ● ●● ● ● ● ●● ● ● ●● ● ● ●ib1● ● ● ● ●● ● ● ● ●● ● ● ● ●● ● ● ● ●ien123457返回iBiB○○ iEiEiBiE○○ iCiCiC● ● ● ●● ● ● ●○○ ○○ ○○ ○○ c● ● ● ●● ● ● ●● ● ● ●● ● ● ●● ● ● ● ●● ● ● ● ●RC● ● ● ● ●● ● ● ● ●bRbECEBe第7页/共37页123457③ 集电极对载流子的收集返回icpicn2icn1●●●● ● ● ● ●● ● ● ●● ● ● ●● ● ● ●● ● ● ● ●● ● ● ● ●● ● ● ●● ● ● ●ib1● ● ● ● ●● ● ● ● ●● ● ● ● ●● ● ● ● ●iEPien○○ iCiEiBiEiBiBiCiB○○ iEiEiCiC● ● ● ●● ● ● ●○○ ○○