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WRansohoff / STM32_LiPo_Example

Simple lithium battery-powered STM32 board using an MCP73831 for charging.
MIT License
15 stars 3 forks source link

MCP73831/2 thermal throttling #1

Open deltabeard opened 4 years ago

deltabeard commented 4 years ago

Hi again.

I've actually been using the MCP73832 since a week ago on a breadboard using a SOT-23 to DIP converter board. Despite programming it to charge at 500mAh, it was charging at around 320mAh instead due to thermal throttling.

This is because this IC has a thermal resistance of 230 C/W, so it gets hot very quickly. This is reduced to <130 C/W with a ground plane. It may be worth attaching your MCP73831 directly to large planes, instead of through vias to stop it from thermal throttling.

I attached a tiny wire as a heatsink to my MCP73832, so it only thermal throttles to 420mAh now...

WRansohoff commented 4 years ago

Oh, interesting - thank you for the tip!

I usually try to include large contiguous ground planes, but this board ended up being a little bit space-constrained with the USB port, toggle switch, and battery connector. 2-layer boards designed to fit a breadboard can get a little cramped, but maybe I could move the charging IC to the other side of the board which is less crowded.

Anyways, thanks again for the information. I should do more testing to characterize these projects' real-world performance, but I already feel sort of behind on writing firmwares and learning how the USB and SD/MMC protocols work. Busy, busy, busy :smile:.