Inductor selection for a buck convertor

[spanker1]

Hi,
I am planning to run some LED's with Iout 1A using a buck convertor. Is it ok if use an inductor with current rating 1A or should i look for a higher value inductor?.
Pleae advice

 

[BradtheRad]

Your question can apply to two different specs:
(1) safe ampacity without overheating,
or
(2) saturation current as an inductor.

Re #1:

Traditional advice is to use a rating twice whatever amount you expect the component to be exposed to.

During part of each cycle your coil will carry greater than 1A. Overall it may average out to 1A. However while testing the project you may cause it to carry more. Will it overheat?

Note also that it may carry a surge current for a few cycles on startup.

 

[spanker1]

Your question can apply to two different specs:
(1) safe ampacity without overheating,
or
(2) saturation current as an inductor.

Re #1:

Traditional advice is to use a rating twice whatever amount you expect the component to be exposed to.

During part of each cycle your coil will carry greater than 1A. Overall it may average out to 1A. However while testing the project you may cause it to carry more. Will it overheat?

Note also that it may carry a surge current for a few cycles on startup.

Thanks a lot. Really appreciate your help.. This is what i was using at first
https://katalog.we-online.de/kataloge/eisos/media/pdf/74437324220.pdf
It has a rated current of 1A and a saturation current of 2A. Thats what i don't understand.
I am thinking of swithcing to a lower inductance but with a higher current rating. This is what i have in mind
https://www.mouser.com/ProductDetai...=4vvWAaIu/q6WChHP9RzeF81ZUVbYDrphbcbdR2hPocU=

please advice

Thanks

 

[BradtheRad]

Please excuse my taking several days to reply.

1.

Inductive saturation current is the plateau at which you get inductive action below that, while above that the flux fields do not build further, and there is just DC resistance.

Your converter may operate the coil so it reaches this point many times a second. There is little use in exceeding it.

2.

Safe current rating applies to long term use. You can exceed this rating if your duty cycle is not too great. In other words if you don't heat up the coil too much.

You may even run it up to and above maximum inductive saturation current, as long as the duty cycle is not too great.

3.

Traditional advice says to rate components for twice whatever you expect them to be subjected to. To power a 1A load you should use a coil rated for 2A safe limit.

Note that a switched-coil converter may have your coil current swinging between .5 A and 1.5 amp per cycle.

Both of the coils you are considering look satisfactory.

 

[spanker1]

Please excuse my taking several days to reply.

1.

Inductive saturation current is the plateau at which you get inductive action below that, while above that there is no further building of flux fields, but there is just DC resistance.

Your converter may operate the coil so it reaches this point many times a second.

2.

Safe current rating applies to long term use. You can exceed this rating if your duty cycle is not too great. In other words if you don't heat up the coil too much.

You may even run it up to and above maximum inductive saturation current, as long as the duty cycle is not too great.

3.

Traditional advice says to rate components for twice whatever you expect them to be subjected to. To power a 1A load you should use a coil rated for 2A safe limit.

Note that a switched-coil converter may have coil current swinging between .5 A and 1.5 amp per cycle.

Both of the coils you are considering look satisfactory.

That was really helpful..
Thanks a lot