We have a new design, with a ESP32 controlling an LTC4015. Everything seems to be ok, it says Ready to charge, but then Charge suspended. Could someone have a look at the PCB design to see if I made some mistake? It's a KiCad design. Please tell me where to send Gerber files or what you need? Thnx in advance!
Thank you very much, we will returen with feedback on lessons from our update design
A quick update - we discovered we had actually left out a decoupling cap for INTVCC which must have gotten removed in some revision (it was present in earlier versions) which caused our 4 layer board to misbehave, but with this in place it works well.
The 2-layer version did not seem to work even with this cap added. For this reason we ended up with a 4 layer board which works well in nearly all respects, except for measurement of IBAT and the coulomb-counter.
The IIN seems to be pegged at 32768 with a battery connected, and the coulomb counter counts down really quickly until it reaches 0.
My current working theory that one of the CSP/CSN inputs get damaged during battery connection as I have tried a couple of chips, and they seem to both exhibit the same problem.
In the specs CSP/CSN is specified with a max difference of 50mV - do you know if exceeding this causes damage to the chip? Do you have any tips for avoiding this?
The abs max differential voltage for those pins is +/- 0.3V. Exceeding 50mV is not a problem.
It is possible that the IC was damaged due to inrush current through the sense resistor, but then a fresh IC would work.
Make sure the coulomb counter is configured correctly and check the CCREFP/CCREFM pins, etc.
Having soldered up a triplet of new boards, I've pretty much confirmed that the IC's had inrush damage - the new ones all work. I will do some aggressive testing on them and see if I can replicate the problem, but the two original chips with a problem had all been through a few solder cycles and some prototyping harassment, so I'm optimistic I won't have the problem going forward.
Thank you for the help, we are very pleased to have a well functioning board that will shortly go into production:)
That's great to hear! Hope all goes well for you moving forward.