Hi,
We are using BQ24040 for charging Li-Pol battery with capacity of 50mAh. When we enable fast charging, the max charging current starts with 210ma even with a drained battery.
ISET resistor value is derived to enable fast charging current of 420mA.
Please comment on this observation.
When TS pin is connect to the ground with 10k resistor, the voltage on TS pin should be ~0.5V. Can you remove the any resistor connecting on TS pin and force a 0.5V on TS?
Yes, I did reviewed the schematic you provided. I do not see any issue with the part of the schematic is showing beside ISET2 connection is not showing. Also TS seems has going out to TS_CTRL which this part of the schematic does not show where it goes to. Therefore in my previous post i have asked the connections. You mentioned TS_CTRL only connect to gnd through 10k resistor.
Since TS is current sourced internally, 10k ohm resistor should bring you to a TS voltage of 0.5V. However, this is not the case when you measure voltage on TS with your current configuration.
Therefore, the next step is to disconnect any connection on TS. Since you mention the only connection is 10k resistor, thus, I asked to remove the R15 and force a 0.5V directly. However, when forcing a voltage on TS pin, please make sure the power source is current limited to small current. Excessive current will distress the TS pin.
I would suggest you to order an EVM and configure the EVM as your schematic and test on the EVM. In this case, you are testing on a known good board and good device with your setting.
