Hello ,I did a small board from an application example with the LTC4121 but after to many test , the LTC4121 still not charge .I dont understand what .. Please can give me some sugestion.
I experienced a similar issue with this device. My board is a 4-layer well-routed PCB (I hope I did it well).
Looking for the signals at the scope, the LTC4121 is working well, after something like 30sec the LTC performs a PV scan and after what the PV remain OC and consequently battery charge current = 0.
I did a lot of work on the PCB, changing R dividers with lower-value resistors, changing the L... But nothing works. I remember that briefly shorting the RUN pin to ground make the chip working again... until the end of the next PV scan. I also remember, but not 100% sure (98% sure), that after a PC scan, when the LTC is stopped and the PV output is OC, that the nCHARG output remains low, indicating that the charge is in progress.
Since my setup looks very similar to the datasheet recommended value and the AC signals looks correct at the scope (before the first PV scan), I believe that my board + components selection are ok. It looks like a silicon issue.