# 12V Power Supply, current distribution, help.

#### CRISHCREATIVE

Joined Aug 12, 2020
12
Hi Friends,

I am an electronic hobbyist and I am working on an audio project. The power supply I use for this project is a 12V dual supply with the current 16 amp.
The project having multiple op-amp boards (20 to 30 boards) and I am stuck at the power supply. How to split 12V power with the required current to each board?

Thank you.

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#### crutschow

Joined Mar 14, 2008
33,367
How to split 12V power with the required current to each board?
You don't have to split the power.
Each board will just take the power (current) it needs.
It's the same as when you plug a piece of electronics into the mains.
The mains can provide a kilowatt of power or more, but each device only takes what it needs.

#### sparky 1

Joined Nov 3, 2018
742
You have 24V * 18Amps = 432 Watts
432 watts / 30 boards = 14.4 Watts each board
Is it possible to check the current again for just one board ?
is everything staying cool ?

#### CRISHCREATIVE

Joined Aug 12, 2020
12
You don't have to split the power.
Each board will just take the power (current) it needs.
It's the same as when you plug a piece of electronics into the mains.
The mains can provide a kilowatt of power or more, but each device only takes what it needs.
Thank you for your reply, I read that there are chances to produce more noise in the audio out if the current is high so little confused and thought to add a current limiting/constant current circuit between mains and each board.

#### Sensacell

Joined Jun 19, 2012
3,331
You show a Computer power supply in your diagram?

Note that the currents available from the different voltage outputs vary a lot, you are not going to get 19 A from the 12V output.
Read the power supply datasheet very carefully.

#### CRISHCREATIVE

Joined Aug 12, 2020
12
You have 24V * 18Amps = 432 Watts
432 watts / 30 boards = 14.4 Watts each board
Is it possible to check the current again for just one board ?
is everything staying cool ?
Thank you. K....got it. actually, I am looking to supply constant current to avoid noise due to high current, ( sorry my logic may be wrong)

#### Sensacell

Joined Jun 19, 2012
3,331
Constant current is not what you want here.

post the schematic for the boards, and tell us what they need.

#### Ian0

Joined Aug 7, 2020
8,954
Balanced line audio avoids the noise, constant current power supply won‘t make any difference.

#### MisterBill2

Joined Jan 23, 2018
16,626
You show a Computer power supply in your diagram?

Note that the currents available from the different voltage outputs vary a lot, you are not going to get 19 A from the 12V output.
Read the power supply datasheet very carefully.
Some "computer" supplies might actually be rated for 19 amps from the+12 output, to run the fans and lights for those toys. But the negative 12 volts will have a much lower current rating. So yes, read the tag very carefully or there may be a surprise.

#### BobTPH

Joined Jun 5, 2013
8,136
Running an audio amp off a constant current supply would be an interesting experiment. i suspect the result would be quite bizarre, that is, if it did not immediately destroy the amp.

Bob

#### MrChips

Joined Oct 2, 2009
29,861
You cannot have it both ways. You cannot have constant voltage and constant current at the same time.
For an audio amp you do not need constant voltage nor constant current.

#### Ian0

Joined Aug 7, 2020
8,954
You cannot have constant voltage and constant current at the same time.
a class-A amplifier gets pretty close!

#### AnalogKid

Joined Aug 1, 2013
10,795
As above, read the power supply datasheet carefully. If it is a switching supply, it might have a minimum load requirement on one output. Also, just because it has equal +/- output voltages, that is no guarantee that the same total current is available from each output;

To prevent noise from propagating from the supply to the boards - AND from one board to another - add a filter circuit to each power supply input on each board.

ak

#### OBW0549

Joined Mar 2, 2015
3,566
The project having multiple op-amp boards (20 to 30 boards) and I am stuck at the power supply. How to split 12V power with the required current to each board?
Forget the "splitting" nonsense; there is no such thing, and you're imagining a problem where none exists. Just connect your op amp boards to the power supply as shown in the diagram you posted.

Newbies are often confused about voltage and current, and mistakenly believe that a power supply somehow "forces" current into whatever load it is powering. It absolutely, positively DOES NOT: a power supply will establish an output voltage (and hopefully regulate it more or less closely to its specified voltage value), and the load or loads will draw whatever current they need at that voltage. The 16 amps you cited is a rating, and tells you the maximum amount of current the supply can provide before bad things (overheating, smoke, fire, automatic shutdown or blown fuse, etc.) start to happen.

(And by the way, if your boards contain the chip complement shown, I cannot imagine them drawing more than 20-50 milliamps each; even with 30 of them, the total current consumption will almost certainly be less then 1.5 amps. So your 16 amp power supply is gross overkill for this project. You don't need anything that hefty.)

You don't need any help; the diagram you posted is correct as-is.

#### CRISHCREATIVE

Joined Aug 12, 2020
12
Running an audio amp off a constant current supply would be an interesting experiment. I suspect the result would be quite bizarre, that is if it did not immediately destroy the amp.

Bob
You cannot have it both ways. You cannot have constant voltage and constant current at the same time.
For an audio amp you do not need constant voltage nor constant current.
Hi, in this project few boards are oscillators, VCO, LFO also VCA s, and sometimes out of 30 boards, only 10 or 20 boards will be powered on rest are in off mode. Does voltage or current effects the oscillators? I mean effect on frequencies?

#### MrChips

Joined Oct 2, 2009
29,861
Hi, in this project few boards are oscillators, VCO, LFO also VCA s, and sometimes out of 30 boards, only 10 or 20 boards will be powered on rest are in off mode. Does voltage or current effects the oscillators? I mean effect on frequencies?
Oscillator frequency might vary with supply voltage. As already pointed out, you do not need constant current supply. What you do need is proper filtering of supply at each board. For low current boards (less than 100mA) a simple RC filter on the power supply rail should be sufficient.

#### CRISHCREATIVE

Joined Aug 12, 2020
12
Forget the "splitting" nonsense; there is no such thing, and you're imagining a problem where none exists. Just connect your op amp boards to the power supply as shown in the diagram you posted.

Newbies are often confused about voltage and current, and mistakenly believe that a power supply somehow "forces" current into whatever load it is powering. It absolutely, positively DOES NOT: a power supply will establish an output voltage (and hopefully regulate it more or less closely to its specified voltage value), and the load or loads will draw whatever current they need at that voltage. The 16 amps you cited is a rating, and tells you the maximum amount of current the supply can provide before bad things (overheating, smoke, fire, automatic shutdown or blown fuse, etc.) start to happen.

(And by the way, if your boards contain the chip complement shown, I cannot imagine them drawing more than 20-50 milliamps each; even with 30 of them, the total current consumption will almost certainly be less then 1.5 amps. So your 16 amp power supply is gross overkill for this project. You don't need anything that hefty.)

You don't need any help; the diagram you posted is correct as-is.
Thank you, useful information. As few boards are here oscillators like VCO, LFO also VCA s, does it affects output frequencies if voltage or current is not properly distributed?

#### CRISHCREATIVE

Joined Aug 12, 2020
12
Oscillator frequency might vary with supply voltage. As already pointed out, you do not need constant current supply. What you do need is proper filtering of supply at each board. For low current boards (less than 100mA) a simple RC filter on the power supply rail should be sufficient.
This is my filter circuit on each board.

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#### MrChips

Joined Oct 2, 2009
29,861
What is the meaning of "Straight-through" for components L1 and L2?
If that means a jumper wire then I would replace it with a ferrite bead or a resistor depending on the amount of current being passed to the board.

#### OBW0549

Joined Mar 2, 2015
3,566
Thank you, useful information. As few boards are here oscillators like VCO, LFO also VCA s, does it affects output frequencies if voltage or current is not properly distributed?
Distribution per se is not an issue; as I said, the diagram you posted is the right way to do that.

What may matter (or might not) is how stable and noise-free the supplied voltage is. Some oscillator designs are very sensitive to supply voltage; others, not at all. It all depends on the oscillator design.