Take Razavi's Electronics 1 & apply a feedback loop around it. The result is: we have gained a deeper understanding, but sacrificed viewers by a factor of ~10. We've come a long way guys, cheers!
01:25 - Intro and Review 03:20 - Improving the Gain in Voltage-Current Configuration >> 10:00 - Input voltage swing due to input current is low as TIA has small input impedance, especially compared to the output voltage that is amplified >> 12:15 - Resistor can approximate current source if it's input voltage is large and impedance that it is connecting to is small >> 13:30 - Closed-Loop Parameters >> 21:00 - Sign of the Feedback K 22:09 - Non-Inverting Amplifier Construction - Changing Current Amplifier to Voltage Amplifier >> 27:20 - Open-Loop Parameters - Problems, differing to later >> 28:38 - Finding Closed-Loop Gain Directly >> 31:05 - Finding Closed-Loop Input Impedance Directly - Utilizing Miller Theorem (as we know voltage swing across only resistance) >> 35:12 - Finding Closed-Loop Gain by Breaking it 37:28 - Current-Voltage/Series-Series Feedback Topology >> 43:05 - Finding Closed-Loop Gain Directly >> 44:59 - Finding Closed-Loop Input Impedance
01:16 Examples of Voltage-Current and Current-Voltage Feedback 03:34 Addition of stages to increase open-loop gain 08:47 High gain leads to large output voltage swing 11:36 Voltage-current feedback network with a resistor 16:45 Understanding the concept of K in voltage-current feedback circuits. 19:13 Feedback is negative 24:26 Erklärung des Aufbaus und der Funktionsweise eines invertierenden Verstärkers 26:34 Understanding the concept of a Transimpedance Amplifier (TI) 31:09 Finding the input impedance of the circuit using Miller's theorem. 33:14 Evaluating different perspectives on voltage-current feedback. 39:02 Setting up feedback network for current measurement 41:06 Importance of input impedance in voltage and current measurements 45:13 Der Eingangsabstand zur gesamten Schaltung ist entscheidend. Crafted by Merlin AI.
02:55 - Because we are minimizing current error, input impedance will be lowered for voltage-current feedback; Because we are minimizing voltage error, input impedance will be increased for voltage-voltage feedback. Everywhere in the loop due to negative feedback changes would be harder to make...
24:10 - Don't we need to take our current source output impedance if it were non-ideal into account? Either way, doesn't our assumption of K=-1/R_F fails now as we change amplifier's input impedance to infinity or some big value? 31:05 & 35:12 - K*A_transimpedance = A_voltage
17:00 - Do we expel feedback K from the circuit when calculating Input and Output impedances, if not, where do we break the circuit as it may impact resistance seen on input/output ports?
Break at Vout right to the R(F). And in this case the KA equals: 1/RF * RF gm1 / (1+RF gm1) * RD1 * gm3 RD2. The only difference is there's no RF gm1/(1+RF gm1) in this video. Actually, when we calculate the K by inspection, we also see an input impedance of "1/gm1" from the left of R(F) which has been neglected in this video. Hence K should equals the (negative) sum of R(F) and 1/gm1.
The A0 of a transimpedance has a unit of (R). It is different from voltage gain which doesn't have a unit and is used used in 32:30 in Millers theorem. I don't understand why professor Razavi mentioned A0 as VOLTAGE gain of the amplifer while he was talking about transimpedance amplifiers.
The easiest way to think about the inductive behavior of the input and output impedances of this shunt-shunt feedback scheme is to know that: 1) A shunt connection will reduce our impedance at that point 2) Obviously, due to the low-pass behavior of our controller/nullor/op-amp, this is not going to hold true for a long range of frequencies 3) Therefore, the opposite will happen. The impedance at the shunt connected node will start increasing -> inductive behavior.
Look at it this way -> the sensing is done directly it takes Vout and gives Vout bw its right terminal to ground There is just a wire to do that job so they are in parallel
Thanks a lot for the courses! They are pretty cool! Will you record also Analog Design I and II courses? By the way it is a pity that the microphone makes a lot of noise :)
For op amp k=-1/RF Closed loop gain by KCL KVL is -RFA0/1+A0 By this G is -RFA0 and K=-1/RF and LG=A0 Way to get G : Break feedback connect RF from negative input terminal to ground (opening loop properly) and get Vout/Iin = -RFA0 as above as G.
Take Razavi's Electronics 1 & apply a feedback loop around it. The result is: we have gained a deeper understanding, but sacrificed viewers by a factor of ~10. We've come a long way guys, cheers!
Good one !
01:25 - Intro and Review
03:20 - Improving the Gain in Voltage-Current Configuration
>> 10:00 - Input voltage swing due to input current is low as TIA has small input impedance, especially compared to the output voltage that is amplified
>> 12:15 - Resistor can approximate current source if it's input voltage is large and impedance that it is connecting to is small
>> 13:30 - Closed-Loop Parameters
>> 21:00 - Sign of the Feedback K
22:09 - Non-Inverting Amplifier Construction - Changing Current Amplifier to Voltage Amplifier
>> 27:20 - Open-Loop Parameters - Problems, differing to later
>> 28:38 - Finding Closed-Loop Gain Directly
>> 31:05 - Finding Closed-Loop Input Impedance Directly - Utilizing Miller Theorem (as we know voltage swing across only resistance)
>> 35:12 - Finding Closed-Loop Gain by Breaking it
37:28 - Current-Voltage/Series-Series Feedback Topology
>> 43:05 - Finding Closed-Loop Gain Directly
>> 44:59 - Finding Closed-Loop Input Impedance
به عنوان یک ایرانی به وجود شما افتخار میکنم۰
01:16 Examples of Voltage-Current and Current-Voltage Feedback
03:34 Addition of stages to increase open-loop gain
08:47 High gain leads to large output voltage swing
11:36 Voltage-current feedback network with a resistor
16:45 Understanding the concept of K in voltage-current feedback circuits.
19:13 Feedback is negative
24:26 Erklärung des Aufbaus und der Funktionsweise eines invertierenden Verstärkers
26:34 Understanding the concept of a Transimpedance Amplifier (TI)
31:09 Finding the input impedance of the circuit using Miller's theorem.
33:14 Evaluating different perspectives on voltage-current feedback.
39:02 Setting up feedback network for current measurement
41:06 Importance of input impedance in voltage and current measurements
45:13 Der Eingangsabstand zur gesamten Schaltung ist entscheidend.
Crafted by Merlin AI.
Thank you so much professor! Very good teacher!
02:55 - Because we are minimizing current error, input impedance will be lowered for voltage-current feedback; Because we are minimizing voltage error, input impedance will be increased for voltage-voltage feedback. Everywhere in the loop due to negative feedback changes would be harder to make...
32:59 but what about Rout
12:09 we could give Vout to the source and Vin to gate for neg fdbk but in that case it would heavily load M3
24:10 - Don't we need to take our current source output impedance if it were non-ideal into account? Either way, doesn't our assumption of K=-1/R_F fails now as we change amplifier's input impedance to infinity or some big value?
31:05 & 35:12 - K*A_transimpedance = A_voltage
17:00 - Do we expel feedback K from the circuit when calculating Input and Output impedances, if not, where do we break the circuit as it may impact resistance seen on input/output ports?
Break at Vout right to the R(F). And in this case the KA equals:
1/RF
* RF gm1 / (1+RF gm1) * RD1
* gm3 RD2.
The only difference is there's no RF gm1/(1+RF gm1) in this video.
Actually, when we calculate the K by inspection, we also see an input impedance of "1/gm1" from the left of R(F) which has been neglected in this video. Hence K should equals the (negative) sum of R(F) and 1/gm1.
Thank You
The A0 of a transimpedance has a unit of (R). It is different from voltage gain which doesn't have a unit and is used used in 32:30 in Millers theorem. I don't understand why professor Razavi mentioned A0 as VOLTAGE gain of the amplifer while he was talking about transimpedance amplifiers.
Me too... But I think A0 is the gain of OP amp, while A1 is the gain of the Transimpedence amp.
The easiest way to think about the inductive behavior of the input and output impedances of this shunt-shunt feedback scheme is to know that:
1) A shunt connection will reduce our impedance at that point
2) Obviously, due to the low-pass behavior of our controller/nullor/op-amp, this is not going to hold true for a long range of frequencies
3) Therefore, the opposite will happen. The impedance at the shunt connected node will start increasing -> inductive behavior.
Thank You Dr.Razavi
13:17 how the resistor in feedback sense the output voltage it is not in parallel .... can any one help out this ?
The Resistor is in parallel with Vout. Because Vout is measured from the output node to GND.
Look at it this way -> the sensing is done directly it takes Vout and gives Vout bw its right terminal to ground
There is just a wire to do that job so they are in parallel
What would be the closed loop output impedance for that final inverting amplifier circuit? How would you derive that?
Thanks a lot for the courses! They are pretty cool! Will you record also Analog Design I and II courses? By the way it is a pity that the microphone makes a lot of noise :)
For op amp k=-1/RF Closed loop gain by KCL KVL is -RFA0/1+A0
By this G is -RFA0 and K=-1/RF and LG=A0
Way to get G :
Break feedback connect RF from negative input terminal to ground (opening loop properly) and get Vout/Iin = -RFA0 as above as G.
14:07
what is the open loop input impedance? th-cam.com/video/a2O59zdMYx4/w-d-xo.html