CS-CMFB reference voltage

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nassim_el85

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Hi

I want to know is there any specific methodology for making or driving the reference voltage of a "Switched Capacitor Common Mode Feedback" circuit in designing an operational amplifier on not?
My problem is that, by using a simple "MOS Diode" configuration for making this voltage, the output common mode voltage will set very slowly at the beginning of the work and to prevent it, I have to use a large current for driving the configuration and so a large power.
Also there is a same problem for making the input common-mode voltage.

Regards
 

for the reference voltage of sc cmfb, just use a dioded mos biased properly. maybe the setup time is long if supply the dioded mos by small current, but in most time, this time is tolerant, i think
the input common-mode voltage of a sc integrator is determined by input cm voltage, output cm voltage and feedback cm voltage if have of the integrator, so we don't need to set it in particular
 

I'm not sure,but I think you can also achieve the required voltages from bandgap references .
 

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