BQ25790: IINDPM/IBUS ADC

Yoshinobu Kagawa

Part Number: BQ25790
Other Parts Discussed in Thread: BQ25792

Questions from customers.

1) Currently, IINDPM is not operating (even if a load of 3A or more is applied from the System side, a current of 3A or more flows).
2) The value of IBUS ADC is 1mA.

By the way, no Error is observed.

Is there anything that could be the cause of these problems?

Regards,
Kagawa

over 1 year ago

0 Jeff F over 1 year ago

TI__Guru*** 143950 points

Hi Kaqawa,

I have only seen this when the current sensing FET between VBUS and PMID is damaged. I recommend trying another IC.

Regards,

Jeff

0 Yoshinobu Kagawa over 1 year ago in reply to Jeff F

Expert 1810 points

Hi Jeff-san,

1) Are there any conditions that could cause the current sensing FET between VBUS and PMID to be damaged?
(e.g., reverse connection between VAC and GND, etc.)
Please let me know if there are any precautions that should be taken to avoid malfunctions during the evaluation.

2) Please let me know what I should pay attention to when setting up ADC IBUS operation.

In the following thread, it is mentioned that bq25792 regularly reports incorrect IBUS,IBAT, does the same problem occur with bq25790?
If so, could you please provide a workaround and register setting values to correctly measure the IBAT and IBUS currents?

https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1020063/bq25792-adc-ibat-and-ibus-channels-are-intermittent-during-otg-operation/3771103?tisearch=e2e-sitesearch&keymatch=IBUS%2520ADC#3771103

Regards,
Kagawa

0 Jeff F over 1 year ago in reply to Yoshinobu Kagawa

TI__Guru*** 143950 points

Hi Kagawa,

Regarding 1, overvoltage on VBUS pin can damage the input current sensing FET.

Regarding 2, the ADC uses the same input current sensing FET mentioned above. If it is damaged, then the ADC cannot report correctly (usually 0). The 2 known ADC issues are:

a. running average cannot be used

b. 12-bit resolution setting reports too low so is no longer recommended.

Regards,

Jeff

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BQ25790: IINDPM/IBUS ADC