Junus2012
Advanced Member level 5
Dear friends,
many designers use the CMFB amplifier to control the whole current of the intended branch, some others control half of it and provide the second part from normal biasing scheme. Some control 25 % of the current and provide the remaining by the biasing scheme.
What I understood is that if we control the whole current we will get the higher loop gain, if this create a stability issue then reducing the loop gain by controlling part of the current is possible beside it is assumed to give faster settling response.
But what I want to ask you is two things
1. is it good idea to controll 25 % of the current ?
2. if we are controlling 50 % of the current does it mean that our CMFB can correct properly for a mismatch in the circuit up to 50 %, smilarly if we talk about 10 %
Thank you
Best Regards
many designers use the CMFB amplifier to control the whole current of the intended branch, some others control half of it and provide the second part from normal biasing scheme. Some control 25 % of the current and provide the remaining by the biasing scheme.
What I understood is that if we control the whole current we will get the higher loop gain, if this create a stability issue then reducing the loop gain by controlling part of the current is possible beside it is assumed to give faster settling response.
But what I want to ask you is two things
1. is it good idea to controll 25 % of the current ?
2. if we are controlling 50 % of the current does it mean that our CMFB can correct properly for a mismatch in the circuit up to 50 %, smilarly if we talk about 10 %
Thank you
Best Regards