the bias point of the cmfb into the folded cascode opamp

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vvchan

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I am designing an op amp (folded cascode - gain boosting - cmfb). In the folded cascode opamp, there is no bias current source (unlike the telescopic design). So how do my cmfb feed in it?
 

use swith cap

Added after 2 seconds:

use swithed cap
 

You can either connect the cmfb point back to the tail current source of the input differential pair or the active loads. Many textbooks have illustrate the idea.
 

vvchan said:
I am designing an op amp (folded cascode - gain boosting - cmfb). In the folded cascode opamp, there is no bias current source (unlike the telescopic design). So how do my cmfb feed in it?
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you can feed in the tail transistor of the input pairs, or the actives loads(I think the pair connect to the input pairs and cascoded ones are better for their high current, then high gm).
 

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