I want to modify this circuit to run on REF gnd.

Thread Starter

Maglatron

Joined Nov 3, 2023
154
I want to modify the envelope detector circuit to run on virtual ground need to swap out resistors and capacitors.
precision full wave peak detector! need to alter for +VS 12Volt -VS 0Volt for reference ground and will need to alter the resistor and capacitors I'll be using a TL074CN for the operational amplifiers. Anyone think they can give it a crack?? the AD8031U1M will also be replaced with an operational amplifier in side of the TL074CN chip! EXAMPLE 1st picture 2nd picture is the one I want altering to have REF gnd (virtual ground) and 3rd picture is The filter circuit can be changed to single supply, using a virtual ground reference: thanks in advance!!!
1701370215884.pngenvelope detector.png
1701370027786.png
 

crutschow

Joined Mar 14, 2008
34,047
Is this good thinking or not?
Depends upon what you want the circuit to do..
You explanation of running on virtual ground, and swap out resistor and capacitors makes little sense.

And why is this posted in the Microcontroller forum when I see no sign of such a device.
Mod edit: moved. - JohnInTX
 
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Thread Starter

Maglatron

Joined Nov 3, 2023
154
might have put in the wrong section, sorry when using the ilter wizard tool https://tools.analog.com/en/filterwizard/ when I change the -VS to 0 from -12 the values of the resistors and capacitors change its a precision full wave peak detector I need to know how to get the circuit to run on virtual ground so that I can use single supply operational amplifiers (rail-to-rail) and a single 12 V supply only.
1701427899868.png1701427804209.png
1701427779437.png1701427533628.png
 
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Thread Starter

Maglatron

Joined Nov 3, 2023
154
Admin please move to appropriate forum section sorry for mix up

Mod edit: Done! - JohnInTX
 
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Thread Starter

Maglatron

Joined Nov 3, 2023
154
perhaps I don't need to swap out the resistors because the last 2 filters just swap around the values but this is the circuit that I want to run from REF gnd 1701428260877.png
 

Thread Starter

Maglatron

Joined Nov 3, 2023
154
The last two filters swap digits when -VS ground is made from -12v to 0v. Because they are the same but not neccessarly the same order, is it that its the same outcome? do I just connect the grounds to the reference and use all of the same values of resistors and caps?
1701430618664.png1701430629120.png
 

crutschow

Joined Mar 14, 2008
34,047
They should work using the REF ground voltage.

But you can't put your bandpass filters in series, since the first will block the signals to the rest.
You need to put them in parallel.
 

MisterBill2

Joined Jan 23, 2018
17,814
The reference terminal on the LM3914 is not a power source, and as a general rule, NO REFERENCE OUTPUT IS EVER INTENDED AS A POWER SOURCE. So it will not power anything. The reference source is powered by an external power source which is not part of the IC, or whatever system that "REF" voltage is from.
Thus, first and foremost,, "REF" is not a power source and so anything depending on it for power will not function.
AND, NO!! The circuit in post #13 will not do anything because first, there is no power connection to the power input connections on the op-amps. Nor is there a power connection for the LEDs. .
In addition, while the battery negative is connected to "ground", nothing else is connected there.
I have not yet evaluated the rest of the circuit, except to see that the non-inverting opamp inputs are not tied to where they should be connected.
So certainly the circuit as shown will not operate at all.
 

Thread Starter

Maglatron

Joined Nov 3, 2023
154
to crutschow, I don't think you understand to be fair the filters work in unison making one effective filter, and to MisterBill2 the REF vitual ground is so that the filters can run from one supply (12V) the REF virtual ground is not going in to the REFout or REFadjacent it goes to Rlo
 

Thread Starter

Maglatron

Joined Nov 3, 2023
154
USE THE FILTER TOOL FOR YOURSELF https://tools.analog.com/en/filterwizard/ work it out then see what you can do to help

The reference terminal on the LM3914 is not a power source, and as a general rule, NO REFERENCE OUTPUT IS EVER INTENDED AS A POWER SOURCE. So it will not power anything. The reference source is powered by an external power source which is not part of the IC, or whatever system that "REF" voltage is from.
Thus, first and foremost,, "REF" is not a power source and so anything depending on it for power will not function.
AND, NO!! The circuit in post #13 will not do anything because first, there is no power connection to the power input connections on the op-amps. Nor is there a power connection for the LEDs. .
In addition, while the battery negative is connected to "ground", nothing else is connected there.
I have not yet evaluated the rest of the circuit, except to see that the non-inverting opamp inputs are not tied to where they should be connected.
So certainly the circuit as shown will not operate at all.
 

crutschow

Joined Mar 14, 2008
34,047
I don't think you understand to be fair the filters work in unison making one effective filter
I do understand how filters work in series.
Do you?
I don't see how all those filters in series will make an "effective filter" whatever that is.
 
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