Junus2012
Advanced Member level 5
Dear friends,
attached is the output stage of a fully differential push-pull class AB amplifier,
in my previous design I used to control the output common mode voltage by using one CMFB connected to CM1 shown in the picture, the circuit was working fine,
it came to my mind why not using two CMFB amplifier instead of one, where the other one is added to control the upper current through CM2 as shown in the picture,
I have simulated the circuit by different type of simulation and I found that loop control is becoming better,
However, I didn't see before designers who used two CMFB, so regardless of the extra power paid for the new CMFB, is there other limitation ?
Thank you very much
attached is the output stage of a fully differential push-pull class AB amplifier,
in my previous design I used to control the output common mode voltage by using one CMFB connected to CM1 shown in the picture, the circuit was working fine,
it came to my mind why not using two CMFB amplifier instead of one, where the other one is added to control the upper current through CM2 as shown in the picture,
I have simulated the circuit by different type of simulation and I found that loop control is becoming better,
However, I didn't see before designers who used two CMFB, so regardless of the extra power paid for the new CMFB, is there other limitation ?
Thank you very much