Find inductor for XL6019 circuit boost converter

Question

I need a way on my PCB to step up 5V to 12V (with currents up to 2A). I've been looking at the XL6019 IC and tried to copy the design from the sample circuit of the datasheet:

I'm currently stuck at the L1 inductor since I'm unable to find a 47uH (reasonably priced) inductor which is rated for 5A. Furthermore if I have a look at the simple boards from AliExpress out there I'm doubting that the inductor they use can handle anywhere near 5A.

How important is this current rating? Or do you maybe know other low cost ICs which could handle 12V with 2A? Thanks in advance!

Answer 1

If you step-up 5 volts to 12 volts and draw 2 amps from the 12 volts, then, by conservation of energy (and power), the current on the 5 volt side is 4.8 amps. That's average current.

Taking inefficiencies into account it might be a shade over 5 amps and probably starting to noticeably saturate the inductor's ferrite core on the current peaks of around 6 amps: -

Image from my basic website.

\$I_{PEAK}\$ is basically 5 amps but, when inefficiencies are considered it's going to be more like 6 amps. Also note this graph in the XL6019 data sheet: -

How important is this current rating?

Well, what do you think based on what I've just said.

Answer 2

So you need to step up 5V to 12V and have 2A output current. This means that the average 5V input current is 4.8A, assuming no losses.

Even if the average output current is 2A, the inductor needs to handle more current because during ON cycle the inductor current is increased to some higher value and during OFF cycle it falls down to some lower value.

The maximum switching current for the chip is typically 5A. Therefore the inductor must handle peak currents of 5A (with some margin) without being saturated with the current.

And the inductor in the image looks like it could handle 5A, but it is hard to judge just based on how it looks.

However, you don't need to worry about the inductor for XL6019 at all, because it can't do what you need. When stepping up 5V to 12V, the output current is rated to 1A as you can see here.

You need another boost converter.