How does error integrator work?

[naisare]

Anybody used error integrator to cancell the opamp offset.
I want to understand this circuit, how does it work..
I have an single ended rail to rail amplifier in unity gain mode (buffer).
The inputs of this amplifier is also connected to differential gm_C filter(integrator) whose outputs are fed back again to the rail to rail amplifier as auxilary inputs.
How does this circuit help to eliminate the offset of the rail to rail amplifier..
If anybody have some documents regarding this, plz send me.
best regards

 

[Humungus]

Re: error integrator

If you upload your schematic we can better hep you.

Anyway, by using an integrator in your feedback loop reduces you input offset with respect to a given reference. As it is connected so that the ouput of the main amplifier is compared to a given reference and this diference is integrated and fed back to an auxiliary input of the main amplifier, the effective offset at the output, that is the input offset of the integrator, is divided by the gain of the main amplifier.

On the other hand, an integrator connected like that places a zero at DC in your overall frequency response.

See attach

 

[naisare]

Re: error integrator

Here is the picture..