I'm using a bq24251 to charge my battery and power my system.
I've already using it on another product, without problems, but on my new product, somehow it's not working accordingly.
R_ILIM = 0R (max 2A from input)
R_ISET = 165R (aprox. 1515mA)
0R between D+ and D-
0R between VDPM and GND
The problem arises when I set between 4.8V and 4.9V on the input. Somehow the battery current goes above 2A.
On this situation, VLDO jumps from 4.75V to 4.49V and VSYS from 3.90V to 4V.
I've measured the voltage on R_ISET. It's more or less 440mV when the current is as programmed, but it arises to 620mV when charging the battery with more than 2A.
The same thing happens (excessive charging current) when I configure the charging current on Register #4. I've managed to limit the charging current by configuring the ILIM on Register #2, but I want the device working on standalone.
On my another product, the voltage on R_ISET is always near 440mV and I had no problems with the charging current.
When the input voltage is > 5.1V the current behaves as programmed. There is some hysteresis because the voltages to enter and exit this condition are not the same.
Is there someone who can help finding where is the problem?