Electronics > Power/Renewable Energy/EV's
Are there any integrated thermal protection PMICs / FETs?
Siwastaja:
Yes, secondary, slow, board-level thermal protection is often necessary, the approach is fine.
Just design the semiconductor side (current sensing, limitation, part rating, etc.) so that in no instances heating is so fast the board-level sensor can't react to it. But part ratings need to be based in some ambient temperature and this means local ambient near the board, and board level sensing and protection will limit this Ta to some sensible value like 60-70 degC leaving some 30-50 degC over RthJ-A.
jusaca:
--- Quote from: sandalcandal on June 23, 2021, 07:44:57 am ---Are these small enough? https://www.littelfuse.com/products/battery-mini-breakers/metal-hybrid-protection/mhp-tac.aspx
--- End quote ---
That was actually a pretty cool suggestion, I wasn't aware that there are bimetall switches as small as these! We ordered a few to test them, they are really nice.
Only problem is with soldering - according to the datasheet we can't solder these, but have to weld the contacts, to avoid heating of the contact materials. We tested careful and quick soldering with a few of the units and it worked quite well... If the cutoff-temperature is shifting by a few degrees due to soldering, that would be no big deal. So I guess we will carefully try to use these with handsoldering.
sandalcandal:
--- Quote from: jusaca on June 29, 2021, 07:50:06 am ---
--- Quote from: sandalcandal on June 23, 2021, 07:44:57 am ---Are these small enough? https://www.littelfuse.com/products/battery-mini-breakers/metal-hybrid-protection/mhp-tac.aspx
--- End quote ---
That was actually a pretty cool suggestion, I wasn't aware that there are bimetall switches as small as these! We ordered a few to test them, they are really nice.
Only problem is with soldering - according to the datasheet we can't solder these, but have to weld the contacts, to avoid heating of the contact materials. We tested careful and quick soldering with a few of the units and it worked quite well... If the cutoff-temperature is shifting by a few degrees due to soldering, that would be no big deal. So I guess we will carefully try to use these with handsoldering.
--- End quote ---
Glad to know it helped! The soldering compatibility is an unfortunate pain. "Good enough" spot welders meant for assembling lithium ion battery packs are pretty affordable. I'd recommend the K-weld which was posted and developed partially on this forum. The chinese buzz box, transformer-based welders aren't particularly nice but are cheap and can be made to work (mostly).
sandalcandal:
Just came across these: https://www.bourns.com/docs/Product-Datasheets/SC.pdf
A similar size but solder-able.
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