RE: Experimenting with Magnetic Components - Boost Converter part 3: Measure the Inductor in action

shabaz — Fri, 08 Oct 2021 17:25:23 GMT

Hi Jan,

Interesting blog post, I too had a similar type of issue recently, and it's a real dilemma how to do it without damaging anything : )

I did a similar thing, use a resistor, but for my particular scenario I was fortunate I could fit it on the 0V side, and took measurements referenced from there knowing I would need to subtract the voltage across components or have errors (some of which I could reduce a bit, e.g. lower resistance current sensing, but that brought it's own issues).

Another option might be to use a hole-in-the-middle hall current sensor since it's still 100 times cheaper than a sliding current probe, but they might not have the response at typical DC-DC converter frequencies.. plus there's a bit of additional inductance since they are large, so it won't work for all scenarios. In the end I figured resistor was 'good enough' and would not introduce many more difficulties other than the obvious : )