Hello,
I have a problem with BQ21040 charging IC. Rset is 1k ohm resistor so that gives me Iset=540/1000= 0.54A charging current but when measuring I only get around 0.15A and decreases as the battery is charging to the full. Charging stops when the current reaches 10% of Iset, around 50mA.
I have tried this using two different Li-Ion 3.7V batteries few times with a different battery voltage (3.5-4.1V). TS is disabled with a 10k resistor to the ground. Current going into Vin is around 0.25A when charging current is 0.15A. LED acts as it should. Input capacitor is 1uF el. and output 2uF ceramic. Voltage on ISET pin is 350mV, TS pin 488mV and VBAT pin voltage is 4V. This is measured while charging with a 0.12A current and a battery pre-charged to 3.96V.
It seems I have the same problem as the gentlemen in this topic which isn't answered:
