100+A Power Distribution Board Design - Noise reduction consideration.

Thread Starter

christopher_88

Joined Aug 22, 2022
4
Hi,
I am currently designing a power distribution board that will take 12V from an external power supply and distribute the voltage to 8 devices. Each of the device will consume 12A and also to two other devices with less current consumption. In my design I would like to add a common mode choke for noise reduction. However I can't seem to find any common mode chokes with a high enough current. My questions is 1. is it a common design feature to include a common mode choke at currents larger than 100A? I only managed to see one component but it was obsolete. 2. After some reading it might seem that an LC low pass filter might be suitable. Is this approach recommended or is there a better noise reduction method.

At the moment I am simply taking 12V and distributing it out via MOSFETS and gate drivers. There will be some hall-effects current sensing in my design as well. The loads are all digital boards. There won't be any sources of high noise like motors in the area.

Thank you in advance.
 

Ian0

Joined Aug 7, 2020
6,293
Hi,
I am currently designing a power distribution board that will take 12V from an external power supply and distribute the voltage to 8 devices. Each of the device will consume 12A and also to two other devices with less current consumption. In my design I would like to add a common mode choke for noise reduction. However I can't seem to find any common mode chokes with a high enough current. My questions is 1. is it a common design feature to include a common mode choke at currents larger than 100A? I only managed to see one component but it was obsolete. 2. After some reading it might seem that an LC low pass filter might be suitable. Is this approach recommended or is there a better noise reduction method.

At the moment I am simply taking 12V and distributing it out via MOSFETS and gate drivers. There will be some hall-effects current sensing in my design as well. The loads are all digital boards. There won't be any sources of high noise like motors in the area.

Thank you in advance.
It all depends on where your earth connection is.
 

LowQCab

Joined Nov 6, 2012
2,506
A Common-Mode-Choke is generally for Filtering extremely High-Frequencies.
Do You expect to have a problem with High-Frequencies ?
( such as Motor/Generator Brushes creating RFI-Spikes, or a nearby RF-Transmitter )

Keep in mind that the minimum Wire-Gauge needs to be #4-AWG or larger.
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.
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WBahn

Joined Mar 31, 2012
27,394
Hi,
I am currently designing a power distribution board that will take 12V from an external power supply and distribute the voltage to 8 devices. Each of the device will consume 12A and also to two other devices with less current consumption. In my design I would like to add a common mode choke for noise reduction. However I can't seem to find any common mode chokes with a high enough current. My questions is 1. is it a common design feature to include a common mode choke at currents larger than 100A? I only managed to see one component but it was obsolete. 2. After some reading it might seem that an LC low pass filter might be suitable. Is this approach recommended or is there a better noise reduction method.

At the moment I am simply taking 12V and distributing it out via MOSFETS and gate drivers. There will be some hall-effects current sensing in my design as well. The loads are all digital boards. There won't be any sources of high noise like motors in the area.

Thank you in advance.
First, take a step back and ask why you want to add common mode chokes? Is noise really a problem? If so, how much noise is there and how much must it be reduced in order to stop being a problem? What kind of noise is it? Is it even the kind of noise that a common mode choke would reduce? Then, where is the best place to put the chokes? On the input where you have 100 A flowing, or on each of the outputs where you don't have more than 12 A flowing? What part of the circuit is sensitive to the noise? Where in the circuit is the best place to mitigate it? What other options are available?
 

Thread Starter

christopher_88

Joined Aug 22, 2022
4
First, take a step back and ask why you want to add common mode chokes? Is noise really a problem? If so, how much noise is there and how much must it be reduced in order to stop being a problem? What kind of noise is it? Is it even the kind of noise that a common mode choke would reduce? Then, where is the best place to put the chokes? On the input where you have 100 A flowing, or on each of the outputs where you don't have more than 12 A flowing? What part of the circuit is sensitive to the noise? Where in the circuit is the best place to mitigate it? What other options are available?
Thank you these questions help a lot. I understand what I need to work on and figure out.
 
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