模拟电子学基础课件第七章.ppt

1、7.1 反馈的基本概念与分类反馈的基本概念与分类7.3 负反馈放大电路增益的一般表达式负反馈放大电路增益的一般表达式7.4 负反馈对放大电路性能的影响负反馈对放大电路性能的影响7.5 深度负反馈条件下的近似计算深度负反馈条件下的近似计算7.2 负反馈放大电路的四种组态负反馈放大电路的四种组态7.6 负反馈放大电路设计负反馈放大电路设计7.7 负反馈放大电路的频率响应负反馈放大电路的频率响应7.8 负反馈放大电路的稳定性负反馈放大电路的稳定性OFxxF ：idifvvvidifiii：0f vcceefRiRiv fofonfRvRvvi 0f iof11fvRRRv 0L R0o v0f vf

2、iidvvv f11ofvRRRvvF LR ov fv idv ovfiidiii fofRvi fofg1RviF LR ov fi idi ovfiidvvv fofffRiiRv fofrRivF LR oi fv)(fiidvvv oifiidiii of11fiRRRi f11ofiRRRiiF LR oi fi)(fiidiii oiofvv (+)(+)(-)(+)(+)fob1fRvvi foRv fiidxxx idoxxA ofxxF iofxxA iofxxA fidoxxx FxA/xxooo AFA 1fA11 FAAA f11 FAFA1f 11 FAAA f01

3、 FA fAAFAA 1fvvvvf1FAAA 99.01 ovfvFv ifvvvAF 9.9mV fiidvvv 1mV0.vvvvf1FAAA 99.01 fiidxxx idiFAxx AFxx 1iid0.1mV1vviid FAvv9.9mVidif vvvFAFAA11f 2f)1(1ddAFAA AAAFAAd11dff 10%10009001000d AA1000.099100011 AF0.1%d11dff AAAFAA101f AFAAnV nsVVNS V1V2V1osnV1V2VV1V2V11A AAVVVA A FA A FsV2nVSANV 2VAidiivRi

4、iifivRi iidfid(1)vvvAF v idifii(1)(1)RAFAF Ri viifivRi idfidi)(1iAFiii AFRR 1iifidiiivR ttofivR idoottxARiv tfiidFvxxx toottFvARiv FARRooof1 ttofivR tsotidsottFiARvxARvi osof)(1RFAR iofxxA ofxxF FA1f fixx 0fiid vvv0iidid rvi0fiid iii0iidid rivfivv 0b2b1 iiofb2b2fvRRRv iovfvvA b2f1RR 0id iifii 0pn vv

5、fo1iRvRv ifiovfRRvvA FA1f 10vfs A0.1v F1000vvo FA5000k)(1ivvoif RFAR0.1)(1vvooof FARRfvo211fvRRRv 0.1211v RRRF912 RRo21RRR i21RRRHMHj1ffAA MAHfFAAAHHHf1 HfMfHfj1ffAA FAAAMMMf1 HMHf)(1fFAf FAAAMMMf1 FAM11 HMHf)(1fFAf )(1MFA ffAALfMfLfj1 FAffMLLf1 HfLfHfffffBW )(VfA)(VffA100dB20lg(dB)vv AA10kHz)(1HvvH

6、f fFAf99.91vvvvf FAAA40dB(dB)vf A100kHz)(1HvvHf fFAf9.991vvvvf FAAA20dB(dB)vf A HHHff)(11AffAFAFAfA idXfXiX 2,1,0,1802fan,n fa 、FA、fXiXfa fXiXidXidofidXFAXFXX 1 FA FAAA1f1 FA1AF 1801)(2nfa 180fa 1801)(2nfa 1 FAFAFA1 FA020lg FA 180fa 180fa 1 FA0dB20lg FAFAFA1 FA020lg FA0ff 180ff 180fa 180ff 20lg0AF 1 FA0ff 180fa 0180ff 0180ff 180ff FA20lg(dB)20lg180mffFAG 0ff fa 0fam180ff m0 m45 .Fconst 0f AHz10 Hz10 Hz107p36p25p1 fff1 FA0dB)120lg(20lg FAa 135a 45m 90dB)20lg(1v1 F/90a 459090180m 80dB)20lg(1v2 F/135a 45135180m v320lg(1)60dB/F m0 a180 =1AF AF 20lg=0dBAF 0p2ff p100.1ff