this post was submitted on 12 Sep 2024
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I've been messing around with circuits my entire life but this design was time sensitive and I've never done my own PCB designs before, so I hired someone to put this together. After getting some test boards, when I plug them in the charger chip gets very hot and smells like burning....

Circuit is just a simple li-ion usb charger and a switch. I've gone through the datasheet for the bq25302 more times than I can count and I'm missing something obvious here. Using it just for delivering power seems to work fine, the problem is only when charging.

I do see R6 + R7 off TS don't have the recommended 10k values, but I don't feel like that would cause what I'm seeing. This is being connected to a 21700 lipo.

Someone mind lending me their eyes please?

bq25302 datasheet - https://www.ti.com/lit/ds/symlink/bq25302.pdf

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[–] cmnybo@discuss.tchncs.de 3 points 1 month ago (3 children)

There should be a capacitor between REGN and ground and BAT and ground.

[–] Shadow@lemmy.ca 1 points 1 month ago (2 children)

Oooh, thanks.

Stupid schematic question for a second, when looking at this:

If the "REGN" above the LED there is just referring to the REGN pin right below, why doesn't the line just go back down to the pin? Is this just a style thing, or does it mean something functionally different?

[–] cmnybo@discuss.tchncs.de 3 points 1 month ago (1 children)

It means the same thing. I would have just drawn a line since they are right next to each other.

[–] Shadow@lemmy.ca 1 points 1 month ago