MP2759 - 3S pack LIFEPO4 12Vin not chargning

Battery Management
1

Hello,

I would like to charge a LIFEPO4 battery pack 3s with the MP2759. I got the dev board and i made some changes for my application. I don’t need to have the primary path from VIN to VSYS, so i made this change:
image
I plug the 12V input and i see ACOK and STAT led solid ON (this mean that the battery shall be in charge). I just changed the VLIM jumper to 15V but the others are still the same as the beginning.
Do you have an idea why it is not charging? Do i really need to connect PMID pin to something? I took a like on the internal schematic and this shall be good to keep only the decoupling capacitor.

thanks you.

2

Hello,

If you are utilizing power path operation, please keep M1 and refer to page 18 and Figure 5 of the datasheet.
If you are still experiencing issues, then you can try connecting PMID to SYS.
Additionally you can monitor the input, Vsys, Vlim, Vsw, and Ibatt.

Best Regards,
Yu