Possibility of converting fully differential gain boosted OPA to single ended ?

[Yanagi]

Good day everyone, for a gain boosted folded cascode OPA, would it be possible to convert it to a single ended output?

https://imgur.com/a/XvEroQi

I guess it would qualify it to be a 2 stage amp. If so, are there any things I should look out for when biasing the circuit, stability wise ?

In the paper “The CMOS Gain-Boosting Technique”, it’s mentioned that ideal UGBW for Aux amp would be between (roughly) the roll off freq and the ugf of the main amp, hence whilst simulating for ac response would it be possible to simply replace Aux amp with normal biasing as if there’s no aux amp?

Would love to know if anyone knows how to perform gain boosting on a single ended 2 stage differential-cs miller amplifier as well.

Any input is much appreciated, cheers!

 

[BradtheRad]

Sometimes your input signal is genuine bipolar AC, centered around 0V and possibly weak (uV or mv). It makes sense to continue this AC mode throughout your op amp (or collection of current mirrors and current sources). That way you can use your input signal unaltered and close to 0V. The workaround is that our power supply must have positive and negative rails (near-universal advice when building with op amps). Then NPNs turn on normally. The output stage operates normally.

We can prefer our op amp to run on a single-ended DC power supply. But then we must apply certain DC bias voltages and mix them with our inputs. We must always keep this in mind as we develop the circuit. We must account for a midway DC level running through all components. We must make an output stage that takes this into account.

 

[Yanagi]

Sometimes your input signal is genuine bipolar AC, centered around 0V and possibly weak (uV or mv). It makes sense to continue this AC mode throughout your op amp (or collection of current mirrors and current sources). That way you can use your input signal unaltered and close to 0V. The workaround is that our power supply must have positive and negative rails (near-universal advice when building with op amps). Then NPNs turn on normally. The output stage operates normally.

We can prefer our op amp to run on a single-ended DC power supply. But then we must apply certain DC bias voltages and mix them with our inputs. We must always keep this in mind as we develop the circuit. We must account for a midway DC level running through all components. We must make an output stage that takes this into account.

Thanks for your advice sir, though this OPA is supposed to be an Error Amplifier of LDO for our AIC final project, which I also plan to use in the Bandgap reference circuit. For this application, do you think the circuit in my diagram would work?

Cheers

 

[BradtheRad]

Though I'm not expert in your topology I've observed many threads at Edaboard about similar circuits. A forum search of your keywords should lead to previous discussions.

 

[nitishn5]

Can you not just diode connect the M7 Transistor ?