Electrical – Difference of inductor rated current based on “Inductance change” vs based “Temperature rise”

currentinductor

I'm looking into an inductor datasheet(page 59) and I'm having a bit of trouble understanding the difference between the ratings.

My interpretation is as follows:

1 – Rated Current based on Inductance Change is:
How much current you can put through the inductor till its inductance goes 30% off the original rating.

2 – If you "dont care" about inductance, the Rated Current based on Temperature Rise is the absolute maximum current the inductor can take before thermal failure.

Is that it? Am I missing something?

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Best Answer

Almost complete. The other factor is that the temperature rise plus ambient must be less than 125°C. So if your ambient temperature exceeds 85°C you must reduce the maximum current down to zero at 125°C.

In other words, if your ambient is 100°C you can only pass 0.63 of the thermal maximum current. 1-(100­°C-85°C)/40°C

You should make sure both constraints are simultaneously satisfied- so the lower of the two currents is what matters.

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