amplitude limiter using op-amp

[curious_mind]

I was browsing this link http://www.ecircuitcenter.com/Circuits/op_limiter1/op_limiter1.htm which provides amplitude limiter circuit using opamps and zener with inverting configuration. Help required to convert the same circuit with non inverting configuration. Also please explain why two zeners are required in this design?

 

[D.A.(Tony)Stewart]

This is for a slow bipolar (Vcc,Vee) limiter, hence dual Zeners. If this what you had in mind for slew rate limited clipping, OK, but if needed something > 1MHz there are better solutions if specs exist.

 

[curious_mind]

It is for dc applications only. Please suggest non inverting configuration for the same.

 

[D.A.(Tony)Stewart]

If by DC do you mean single DC supply or just a DC sensing comparator?

The best solution for a limiter is a comparator in CMOS or ECL/ICL for high speed.
Non inverting is easy with reference voltage on Vin- and rail to rail or any logic level out as required.

Most people think Op Amps are OK for limiters/slicers or as comparators, but they are compromised due to internal compensation cap.

But for DC sensing you just use Vin+ for DC input and Vin- for threshold = Vref. Either input or both may be scaled to use an existing stable reference or bandgap voltage ref or programmable Zener Ref..

arbitrary example of CMOS Op Amp with test triangle input

https://tinyurl.com/ywml9kst

 

[FvM]

There's no simple non-inverting limiting amplifier with clamp circuit in feedback path. Because non-inverting amplifier has gain of 1 + feedback network gain factor.
What's your intended gain?

 

[D.A.(Tony)Stewart]

If just comparing DC levels with a threshold, then I guess you mean to say just a logic level output rather than an analog output.

 

[KlausST]

Hi,

a brief explanation about signal voltages:
In a OPAMP circuit (in regulation = non saturated):
* the IN+ voltage determines the IN- voltage. --> The OPAMP regulates the output in a way that IN- becomes the same as IN+

Now in your case
* IN+ = GND = 0V, thus IN- also becomes 0V, too.
* since you have the two diodes in series, the limiter becomes active when the voltage across the diodes (V_Out - V_IN-) is V_fwd + V_rev of the diodes = 0.6V + V_Zener.
* and this in both directions.
(in real world neither 0.6V nor V_Zener will be precise. Both depend on production, current and temperature)

**
If you use such a diode limiter across the feedback with a non inverting OPAMP circuit .. then the voltage at IN+ is not constant, it is the input voltage.
So it limits at (V_IN+) +/- (V_fwd + V_rev).

***
If I wanted the limiter to be non inverting, I´d use two inverting circuits in series.
But often "inverted signals" are no problem at all. In detail it depends on your application´s requirements.
***

It is for dc applications only.

What do you mean?

Klaus

 

[crutschow]

Below is the LTspice simulation of an accurate, non-inverting clamp circuit using one quad opamp package:
The positive clamp is determined by the Clip_High voltage and the negative clamp by the Clip_Low voltage.

What are your input voltages and at what level do you want to clamp?

 

[D.A.(Tony)Stewart]

I was browsing this link http://www.ecircuitcenter.com/Circuits/op_limiter1/op_limiter1.htm which provides amplitude limiter circuit using opamps and zener with inverting configuration. Help required to convert the same circuit with non inverting configuration. Also please explain why two zeners are required in this design?

You have yet to define all the parameters for inputs and output.

bipolar supply?
frequency range?
Amplitude range?
Offset , duty cycle error tolerance.
Noise limit.