BQ25720: CHRG_OK oscillation

Hi Fred,

I would suggest monitoring the system current and adapter current as well. It looks the VSYS is pulled to low when the CHRG_OK asserted. 

Regards,

Tiger

Hi Tiger,

here's adapter current and discharge current in IBAT.

but like I said, there're no fault in 0x20, and VBUS is normal.

so we're confused what's the root cause.

please guide us, thanks

Hi Fred,

I noticed STAT_VDPM was triggered the PROCHOT status. You can lower the input voltage register 0x3D to see if it continues to trigger VINDPM. 

For debugging purpose, you may enable other PROCHOT options bit to see if which event triggers. 

Regards,

Tiger

Hi Tiger,

got it, but VDPM is not one of trigger condition of CHRG_OK.

is this correlated? 

Hi TIger,

but what I mean is prochot is not the trigger condition to CHRG_OK,

0x20 covers all the SYSOVP, SYSUVP, ACOC, TSHUT, BATOVP, BATOC or force converter off fault.

and like I said they haven't seen any item being triggered.

they found oscillation of CHRG_OK is still happening after they fixed VDPM. and VBAT seems stable only Vsys is dropping every cycle.

please guide us for next step.

please also see schematic.

Oski_RPL UMA TI 20221230 (1).pdf

It looks the EXTILIM is set at 500mA, while the adapter current is higher than the current limit. Maybe you can disable IINDPM and try if it is related to ILIM. 

Regards,

Tiger

Hi Tiger, 

but they didn't enable EXT_LIM bit,

why would you suspect this one?

I think we need to set up a meeting and gather other people in  to help on this, customer is waiting urgently.

Did you try our suggestions? Feel free to call a meeting and provide the schematic, layout and register maps. 

Hi Tiger,

we did, it's not helping.

update more waveform and EC log

below is the EC log,

I do see they keep writing 0x15(max charge voltage) to 8.8V every 3 sec which is would be BATOVP in 3S setting, right?

please help double check carefully .

bat3.txt

"229C" is 8.856V, please help check

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