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Yes you are right..the Vbe0 values should be the same at node A(B) and node D..so any deviation will result as an offset (in this case it will be CTAT) which again has to be adjusted by tuning either or both of R2, R1
May not be in a direct way....as per the theory, current into Q3,Q4 needs to be a constant current and without R5, it wont be constant exactly...there will be some nonlinearity, so i am guessing that R5 is just making sure that the current into Q3,Q4 is relatively more constant. So there might...
Hi, i guess you are right...the R5 terms shouldn't be there..it is the R4 which is supplying the Non-Linear current....seems to me that R5 is just trying to make the current through Q3,Q4 a bit more constant...
i am not sure how m2, m4 can come into the picture...assuming strong inversion...delta_vgs = vgs1-vgs3 = sqrt(2*I/k) - sqrt(2*I/4*k) (neglecting body effect...factor of 4 because f3/f1 =4)
hi..i don't think that the equation is correct...the voltage across the resistor will be delta_vgs = vgs1-vgs3 and thus the current will be delta_vgs/R...thus for smaller R u get larger currents
i don't think, it is the problem caused by opamp...as long as you have enough loop gain (stability, output swing..) it should serve the purpose...in order to get a parabolic curve..the resistors need to be ratioed appropriately(R1=R2 and Rprog need to be adjusted) such that the first order terms...
I don't think you need to change the Is values...you can use 1 unit (bjt) for Q2 and have 8 (as shown in the figure or any desired ratio) units in parallel for Q1..that should serve the purpose.
Hi....vc1=vc2 doesnt mean that ouput will be zero here. The amp is in a closed loop and if the closed loop gain is high enough, the amp output will be regulated in such a way that vc1 follows vc2 (the offset between vc1 and vc2 will depend on the finite closed loop gain and the random mismatches...
If you are doing lstb analysis, you can break the loop right at the output of the opamp (rather than in the -ve fb loop). Introduce the lstb source between the output of opamp and the current mirror gate and the final result gives you the effective loop stability
you can control the gm(aspect ratio and bias current) of your input pair, ro of our loads (length, bias current) to get the required gain.
also depending on whether your input pairs are biased in saturation or subthreshold, gm could be lower or higher.
I guess it could be either way. It depends on how the compensation is being done. Assuming first order compensation vref=k1*vbe + k2*delta_vbe. So depending on how the constants are set, i guess vref could be upward or downward concave.
I dont think you can forward bias the bulk-source junction (NMOS). So the bulk always should be at a lower potential and with higher source voltages your vth increases
By gm i mean the transconductance of the mos. For constant-gm biasing you can refer any of the books on analog ckt design (razavi or grey, meyer) or some of the threads in eda have the references.
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