Why is IC1 = Iref - 4IB, in the first stage doesnt IB1 flow back into the emitter of Q1? That would give IC1 = Iref - 3IB, if you could tell me what my mistake is I'd be very grateful, thanks!!!
Hello Dr. Christina, Dr. Aboy- can you confirm that the circuit is drawn correctly? I've only seen this circuit with the 2 bases of Q3 and Q4 connected back to the node sinking current from Io, instead of the node sinking current from Iref. As I have seen it, it is called the improved Wilson current mirror, because it builds on the Wilson current mirror by balancing the Vce drops. Is that correct?
Thanks Dr. Aboy. Upon analysis it appears that, if we make the same general assumptions between the two structures, we end up with a similar Rout and Vcompliance. Is that correct? I looked a bit on the net and found some discussions that indicate an improved wilson is more appropriate for circuits using BJT and the cascode was preferred in the use of CMOS. I couldn't follow their reasoning, but assumed there must be some virtue in using one over the other for specific use cases. Any insight you could share would be apppreciated. (By the way- thanks for the videos, I've really enjoyed them!)
The cacode output resistance in case of a cascode current mirror is (beta)/2 * rO
Why is IC1 = Iref - 4IB, in the first stage doesnt IB1 flow back into the emitter of Q1? That would give IC1 = Iref - 3IB, if you could tell me what my mistake is I'd be very grateful, thanks!!!
Hello Dr. Christina, Dr. Aboy- can you confirm that the circuit is drawn correctly? I've only seen this circuit with the 2 bases of Q3 and Q4 connected back to the node sinking current from Io, instead of the node sinking current from Iref. As I have seen it, it is called the improved Wilson current mirror, because it builds on the Wilson current mirror by balancing the Vce drops. Is that correct?
The circuit is correct. This is not an improved Wilson current mirror. It is a cascode current mirror.
Thanks Dr. Aboy. Upon analysis it appears that, if we make the same general assumptions between the two structures, we end up with a similar Rout and Vcompliance. Is that correct? I looked a bit on the net and found some discussions that indicate an improved wilson is more appropriate for circuits using BJT and the cascode was preferred in the use of CMOS. I couldn't follow their reasoning, but assumed there must be some virtue in using one over the other for specific use cases. Any insight you could share would be apppreciated. (By the way- thanks for the videos, I've really enjoyed them!)
what is the book you are speaking in this videos ? from where should i get/buy a copy ?
can you draw the small signal equivalent circuit of this
What textbook are you using ? Thx
Most probably Seadra And Smith
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