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.
In meantime i change the RFB1 and RFB2 to 1.4 M both resistor to reduce the baterry feedback tension , but without sucess .
The LTC4121 is sensitive to the placement of 3 external capacitors. On the schematic you show, these capacitors are CIN, CBOOST, CINTVCC. You should try to place these capacitors as close to the LTC4121 as possible with very short etch. If this doesn't help, I will want to study your layout.
robertofonte, have you repaired the circuit?
WATaylor, I have a simple scheme for charging a single lithium cell. All the capacitors are in place, the printed conductors are short, nCHG = 0, nFLT = 1 is OK, but the PWM signal is missing.
The input voltage is 8.4V, the 3.4V lithium battery is not charging.
Resistors in feedback 1M and 1.51M. MPPT is not required (10k pullup, but Vmppt = 0).
Vout float = 2,77 V, Vfb float = 1.68V.
Rprog=4.7k (also 3k), Vprog=0.
Why the converter does not work?
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