Author Topic: Inductor Help  (Read 542 times)

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Offline bigjoncoopTopic starter

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Inductor Help
« on: August 11, 2021, 03:36:09 am »
hey,

im trying to copy a lithium usb charging board based on the tp5000 ic..

im trying to design my own and have them assembled by jlbpcb since i can order a bunch and have them within 1 week instead of waiting a month..

ill post a picture of said board.

**the schematic and datasheet just show a 4.7uh inductor but no other specs.
but on jlcpcb parts inventory they have a bunch of 4.7uh smd inductors with different DC Resistance (DCR) and rated current...
im assuming i need one with a rated current of my circuit but what about the DC Resistance (DCR)???  they range from 19mega ohm to 500 mega ohm... 

any ideas of which one would be best?

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« Last Edit: August 11, 2021, 03:38:23 am by bigjoncoop »
 

Offline hagster

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Re: Inductor Help
« Reply #1 on: August 11, 2021, 05:35:21 am »
Hopefully the DCR is in Milli ohms not Mega.

A lower DCR is more efficient.

You should also check the self resonant frequency SRF. This needs to be significantly higher than the switching frequency(800khz).
 

Offline james_s

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Re: Inductor Help
« Reply #2 on: August 11, 2021, 06:07:16 am »
I think that's probably milli ohm, not mega. 500 megohms would be ridiculously high for an inductor. Assuming it's milliohms you want the lowest possible in most cases.
 


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