Download presentation

Presentation is loading. Please wait.

Published byTyra Tindel Modified over 2 years ago

1
Common-Collector Amplifier Section 13.1-13.4

2
Topics Emitter Follower as a power amplifier Push and Pull Output Stage

3
Design Guideline Specs: Av, rsp, v_re gm=Av/(1-Av)/rsp Calculate IC from gm. Determine re from IC and V_RE Calculate VBE. Calculate VB. Calculate IB from IC. Assume that I1=40 IB Calculate R2 from VB. Calcualte R1

4
Common-Collector Amplifier

5
V in, m =1 mV V in,pp =2 mVV out,pp =1.47 mV Av(ADS)=0.735 Av(matlab)=0.783

6
Large Signal Behavior of Common-Collector Amplifier The output does not track the input during the negative swing.

7
V in, m =1.71 V V BE

8
Push-Pull Stage Q1 pushes current into RL. Q1 pulls current from RL. Q1 and Q2 are off. Assume that VCC is +5V and VEE is -5V.

9
Vout versus Vin

10
DC Sweep

11
V out Versus V in

12
Transient Simulation

13
Vout Versus Vin Crossover Distortion

14
Improved Push-Pull Stage Q1 and Q2 can not be on at the same time! Keep Q1 and Q2 on V1=Vout+VBE1 V2=Vout-|VBE2| V1-V2=VBE1+|VBE2|=VB

15
Example 13.5

16
Implementation of VB Add I1 to provide current For D1 and D2.

17
Current flowing through the Source

18
Improved Push-Pull Stage Use Q4 to drive the base of Q2

19
DC Bias

20
Voltage Gain Full circuit

21
Voltage Gain from Vin to VN Full circuit To compute VN/Vin, Calculate RN and multiply RN by gm4.

22
Voltage Gain from N to Out Full circuitGeneral formula: RL/(1/gm+RL)

23
Small Signal Model of BJT Transistors (NPN)(PNP)

24
Sanity Check Intuition: gm1=gm2, rpi1=rpi2 Vout/VN=(1+2gm rpi/2)/(rpi/2/RL+1+2gm rpi/2) =(1+beta)/(rpi/2/RL+1+beta) ~=1/(rpi/2/RL/beta+1) =RL/(/(2gm)+RL) Compare Vout /Vn to the generic formula: RL/(1/gm+RL) we see that this formula makes sense!

25
Voltage Gain

26
Output Impedance

27
Sanity Check! R S is transformed to a smaller output resistance.

28
Cadence Simulation

30
Gain Calculated Using Matlab

31
Change R to change Gain. Tweak R to change gm and the gain at the expense of burning more power.

Similar presentations

OK

● Establish a constant voltage V B. ● Current-derived negative feedback.The degree of success of the negative feedback is Bias Stability. Biasing Circuit.

● Establish a constant voltage V B. ● Current-derived negative feedback.The degree of success of the negative feedback is Bias Stability. Biasing Circuit.

© 2017 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Ppt on event driven programming in visual basic Mobile application development seminar ppt on 4g Ppt on object-oriented concepts java Convert word doc to ppt online shopping Free ppt on mobile number portability status Download ppt on journal ledger and trial balance Ppt on cloud computing projects Animal sounds for kids ppt on batteries Ppt on edge detection techniques Ppt on coalition government examples