Input Commom Mode voltage: Switched Capacitor circuits

[mvj]

Dear All,

In switched capacitor circuits such as inverting/non-inverting amplifiers and multiply by 2 circuits, there is always a period of time during which the output and one of the input terminals are shorted ( like a buffer configuration). My understanding is that this is done in order to establish a proper common mode input voltage. However, in case of switched capacitor Active filter circuits, there usually is never a period of time during with such operation is done. May I know why this is so.

Thanks a lot in advance!!

Best Regards,
M.

 

[leo_o2]

Buffer configuration is used to store offset. It is not necessary for some filter circuits.

 

[nassim_el85]

It may act in that period of time as a buffer, helping to store the input or output signal on a capacitor.