BQ40Z50: How to enter PF mode without disabling FETs on BQ40Z50-R5?

HJ_KIM

Part Number: BQ40Z50

Tool/software:

Hello,

I’m working with the BQ40Z50-R5 gauge and would like to understand if there is a way to trigger a Permanent Fail (PF) event while keeping CHG/DSG FETs enabled.

According to the TRM, entering a PF state disables the FETs. However, for system diagnostic or logging purposes, I want to log a PF event (i.e., set a PF flag in the PF Status register) without affecting the actual operation (no shutdown or FET off).

In summary:

Is there any way to enter PF state without disabling the FETs on BQ40Z50-R5?
Are there specific PF bits or PF settings that allow logging PF without protection shutdown?
If not, are there any known workarounds such as using ManufacturerAccess() commands or modifying PF configurations (Data Flash)?

I reviewed both the R2 and R5 TRMs, but couldn’t find a clearly documented option.

Any official guidance or references would be greatly appreciated.

Thank you.

2 months ago

0 Alan Frias 2 months ago

TI__Mastermind 26045 points

Hello HJ,

This question has been assigned and a response is being worked on.

Thank you,
Alan

0 HJ_KIM 2 months ago in reply to Alan Frias

Intellectual 485 points

Is there anything confirmed?

0 Alan Frias 2 months ago in reply to HJ_KIM

TI__Mastermind 26045 points

Hello HJ_KIM,

Due to current workload from the person this question has been assigned we are asking for more time to work through the queue.

Thank you,
Alan

0 HJ_KIM 1 month ago in reply to Alan Frias

Intellectual 485 points

When can I check the answer?

0 Anthony 1 month ago in reply to HJ_KIM

TI__Mastermind 28470 points

Hi HJ,

The Permanent Fail functionality will always disable the CHG/DSG FETs, where there is no way to disable this by configuration.

Can you please give more information on what is trying to be achieved? If this is being done for testing, the PF_CLEAR command can reactivate the FETs without power cycling.

Regards,

Anthony

0 HJ_KIM 1 month ago in reply to Anthony

Intellectual 485 points

Thank you for your answer. The reason I need is that our product is a drone, and we are looking for a way not to crash even in the abnormal situation (PF) of the battery. So, is there a way to keep the FET from turning off while recognizing the PF situation?

Best Regards,

0 Alan Frias 1 month ago in reply to HJ_KIM

TI__Mastermind 26045 points

Hello HJ,

We have received your update and will follow up with a response when possible.

Thank you,
Alan

0 Anthony 1 month ago in reply to Alan Frias

TI__Mastermind 28470 points

Hi HJ,

If you are triggering the PF, they will always trigger the disabling of the FET state. You could possibly send the PF_CLEAR command right when the PF is seen by the host to clear it, however if it doesnt see it immediately there will still be a change in the FET state.

Regards,

Anthony

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BQ40Z50: How to enter PF mode without disabling FETs on BQ40Z50-R5?