D-Noizator: a magic active noise canceller to retrofit & upgrade any 317-based V.Reg.

OK, until I find more generic LM7815 models, I'm using LT1083-12 models for these simulations of Diego's fixed voltage Dienoisators.

For illustration I have also simulated the fixed regulator with no Dienoisator.

You can also see what happens with the PSRR curve when R3 is changed from 180K to 330K, with a flattened extension on the below 10Hz frequencies, down to 7Hz.
 

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These are Elvees' version PSRR curves, exchanging different values for R3, as Diego suggested.

Other simulations in order, but most of all breadboard or prototype board assembly, and actual measurements to confirm or not the simulation results.
 

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Sorry I needed the schematic from post 619 referring to lm317/337 for 10v operation

Thx

Possibly, a start value can be 680 ohms for the resistor located between the base and emitter of the BC327 (for the LM317 regulator).

It would not be unreasonable to use a 2K trimpot instead of that same resistor, in order to find the most optimal value, similar to the Fixnoiser.

By short-circuiting the trimpot, the Dienoiser would become Denoiser!!! :D

Best regards
 
Last edited:
Possibly, a start value can be 680 ohms for the resistor located between the base and emitter of the BC327 (for the LM317 regulator).

It would not be unreasonable to use a 2K trimpot instead of that same resistor, in order to find the most optimal value, similar to the Fixnoiser.

By short-circuiting the trimpot, the Dienoiser would become Denoiser!!! :D


Best regards

He he got it😎
 
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In post 655
D-Noizator: a magic active noise canceller to retrofit & upgrade any 317-based V.Reg.
Elvee mentions C5 needs to be reversed for the 78xx version.

In post 643 Elvee is referring to the LM317 version.
D-Noizator: a magic active noise canceller to retrofit & upgrade any 317-based V.Reg.

In that schematic the positive side of the same capacitor (now C3) is connected to the Adj-pin of the LM317. In this case the potential for C3 at the Adj-pin is higher than at the noise-filter side. So there the direction of mounting C3 should stay as is.
Correct?
 
In that schematic the positive side of the same capacitor (now C3) is connected to the Adj-pin of the LM317. In this case the potential for C3 at the Adj-pin is higher than at the noise-filter side. So there the direction of mounting C3 should stay as is.
Correct?
Yes: with adjustable regulators, the adj. pin will normally be always more positive than the collector of the correction transistor.
With fixed regulators and GND-referenced regs (the ones having an explicit GND pin), the situation is reversed
 
In principle, loop gain manipulation can be applied to almost any regulator, with many caveats though: the circuit needs to tolerate the additional gain, and if it has already been optimized in this respect, it will be difficult.

The general method is to replace the AC-improvement capacitor with an amplifier.

The location of this capacitor depends on the regulator's topology: for floating, 317-like regs, the cap is between the FB and GND, but for more conventional, discrete types, it is between FB and output.

If you provide example(s) of regulators, I can show you where the augmentation amp should be connected..

For a discrete or semi-discrete regulator, it would probably be more advantageous to include the additional gain in the existing circuit, rather than grafting an add-on.
Remember: the denoiser has been designed a retrofit for fully integrated regs, where you have no access to the internal amplifier
 
In principle, loop gain manipulation can be applied to almost any regulator; ....the general method is to replace the AC-improvement capacitor with an amplifier.The location of this capacitor depends on the regulator's topology....If you provide example(s) of regulators, I can show you where the augmentation amp should be connected.
Ooh, this could be very useful!! How about a RC4194 regulator? (https://www.soemtron.org/downloads/disposals/rc4194db.pdf)
 
Here is a tentative (I hope I didn't make a silly mistake!):

attachment.php


The values of the C2's could certainly be reduced, considering the impedance they drive.

The polarities of the cap for the left (+reg) are correct, but for the -reg, the polarity of C2 will depend on the output voltage.


No compensations are shown: two strategies would be possible:
1-Adapt the 4194 compensation until the circuit is stable
2-Use the regular (but adapted) compensation of the denoiser (10nF cap) and leave the 4194 untouched
 

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