Non inverting opamp, with inverted signal

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Its a non inverting integrator. The inverting fdbk input is grounded. The
NI input is the drop across the current sense R.


Regards, Dana.
 
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Thanks, and so the transfer function Vout/vin = (1 + Zfb/Zin)...and so we should multiply this by minus one because the non inverting input always goes negative of ground?
 

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Thanks, i appreciate it looks like a non inverting opamp...but it cannot be, the transfer function for noninv is 1+ZFB/ZIN...and this is always >1. That cannot be so for an error amplifier in an SMPS...so it in fact, must be a inverting amplifier, with transfer function, -ZFB/ZIN.
 

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Gain falls to 0 if we go far enough out in freq :



This circuit is a NI Integrator :




Regards, Dana.
 
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Thanks , if its a non inverting opamp, then gain is still >=1 even if the freq is high enough to make all the caps shorts.
 

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The G goes away because the interior G elements run out of gas. To wit why the
sim shows this, accurately. Of course the DC case quite different.

And if we use 100% fdbk, a follower, the G is still < 1 because of finite Aol, even at DC.



What is the typical error of a voltage follower opamp

I am trying to identify design elements that might have error from unit to unit. In the design I am looking at, there is a voltage follower configuration for an opamp (in this case, an LM2014), wh...
electronics.stackexchange.com


Regards, Dana.
 
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I believe you are talking at cross-purposes.
1. It's true that the non-inverting circuit has not exactly the inverted transfer function of the inverting circuit but Hni(s) = 1 - Hi(s).
2. With an ideal OP, |Hni(s)| >= 1, as stated.
3. OP open loop gain modifies the transfer function, not specific for this circuit.
 
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