How to use 4 pin inductor

[innovationhut]

I bought an inductor, when it got delivered it had 4 pins, I want ti use it in buck converter.

According to the data sheet it is

ROXBURGH - CMV80 - CHOKE, COMMON MODE, 2X0.74MH, 8A

https://uk.farnell.com/jsp/search/productdetail.jsp?CMP=i-ddd7-00001003&sku=1187668

Could some body please tell me how to use it in buck converter, in terms of pin configuration.

Best Regards

 

[WimRFP]

Hello,

This is a common mode choke for EMC filtering. The current through the coils must be equal and such that the net field in the core material is zero.

This choke is not designed for energy storage (as in a buck converter) so is not recommended. I recommend you to buy a normal inductor.

 

[keith1200rs]

You could use it, either just one half or with the two halves in series or parallel depending on the current capability you require and the inductance you want. Not ideal, but it should work for a test until you get the correct inductor.

Keith

 

[WimRFP]

Hello Keith,

It is a common mode choke. So the wanted current must flow in both windings and should cancel the magnetic field (so that the wanted current is not affected by the inductance).

It has 700uH and a core cross section of about 7*10mm2 = 70u m2 (derived from dimensions in datasheet). As it is designed for common mode suppression, it will have no air core.

Assuming permeability of about 2000 and a path length of 72 mm, one requires about 17 turns to get 700uH. To reach 200mT in the core material you require 0.34A only. So he can use it for a low current buck converter only (while the CM current rating is 8A).

Maybe the original poster can tell us what he wants to do. Microcontrollers is not the best forum for these type of questions.

 

[keith1200rs]

Hello Keith,

It is a common mode choke. So the wanted current must flow in both windings and should cancel the magnetic field (so that the wanted current is not affected by the inductance).

Yes, I realise what it is intended for, but it can be wired up the opposite way to use as inductor. You are right about the current rating though - it will be a lot less than when used as a common mode choke.

I guess he has just mistakenly bought the wrong thing.

Keith.