Please help and comment on my common mode choke circuit.

Hi

I am using a triple voltage +/-15V and +5V SMPS to power up linear circuits inside my hifi amplifier. I want to put in common mode chokes at the input and all the outputs. This is my schematic. I use two common types of mode chokes, 1mH 0.3ohm is for low current +15 and -15V. I use the 500uH 0.11ohm resistance for the +5V that provide higher current. For AC 115V input, I use the same 1mH.

In order to reduce the numbers of different components, I connect the 1mH as inductor as shown for +/-15V as 2mH inductor as shown. The parts I used are:

https://www.digikey.com/scripts/DkSearch/dksus.dll?Detail&itemSeq=262670078&uq=6366357125712924321mH for low current.

https://www.digikey.com/scripts/DkSearch/dksus.dll?Detail&itemSeq=262673778&uq=636635712571292432 500uH for +5V that use more current.

Here is the schematic, Please take a look and comment. Also, is the 1mH safe to use in AC input? The data sheet said it's good for 500Vrms, did not specify for Vac.


Thanks

Alan

I input the schematic into capture, this is a better drawing:

When using a common mode choke as inductor, expect core saturation at a low fraction of rated current.

The other bad point is that you connecting three CM choke windings in parallel, reducing the total CM inductance respectively.

FvM said:

When using a common mode choke as inductor, expect core saturation at a low fraction of rated current.

The other bad point is that you connecting three CM choke windings in parallel, reducing the total CM inductance respectively.

Click to expand...

Thanks

What is the best way for 3 common mode choke? Get the ones with 4 windings? I thought if I put them with their axis perpendicular to each other, there will be minimal interference, is that the case?

Actually I was looking on ebay, I cannot find a tripled voltage SMPS that is thin enough to fit the space I have, I likely going to go 3 individual small SMPS. Will my circuit work?

As for derating of the common mode choke used as inductor, is the derating HALF as there is double the winding turns?

Thanks

A choke is a power magnetic component which is used in electronic circuits. It is an inductor that is utilized to block high-frequency, alternating current (AC) in a circuit while allowing lower frequencies, or direct current (DC), through. The choke normally consists of insulated wire that is wound around a magnetic core