BQ40Z50-R2: gg.csv PF Status

Hello Hans,

Can you clarify your question further? The Black Box data gives information about the state of the battery at specific points before and after the first PF. If the OTC was cleared on the second PF event then the PF status may not reflect the OTC was set, you would need to look at the black box data.

Sincerely,

Wyatt Keller

Hello Wyatt,

here some background for my question:

The battery was under test IEC6000-4-6 by customer. He thinks the condition was charging near 100% RSOC. Suddenly the Pack Pin Voltage get down to 0V and operation status bits XCHG, XDSG and PF was set.

We protect the circuit by a SCP fuse and I found out that this was blown by a PF.

In firmware, the PF bits are enabled:

SUV, SOV, SOCC, SOCD, SOT, SOTF, CFET, DFET, FUSE, AFER, AFEC, IFC, DFC

and fuse blow is allowed for:

SOV, SOCC, SOCD, SOT, SOTF

Now, I have to found out which event blow the fuse… I think IEC 6000-4-6 can affect the PF CFET and DFET but it is not allowed to blow the fuse. The BBR entry shows an OTC in Safety Status B event 3 and CFET/DFET in event one and two (see post BQ40z50-r: Black Box Recorder).

Can OTC trigger SOT or SOTF and why I can’t see it? I think, when the first PF event looks the FETs, the ASCDL and ASCD (gg.csv PF Status) must be earlier, or am I wrong?

It is important for us to find out, what event blow the fuse.

Please help to determine the behavior.

(gg.csv can be send by PN)

Regards,

Hans

Hello Hans,

It seems that the CFETF is the first protection to occur based on your other E2E post (https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1239558/bq40z50-r2-black-box-recorder)

The fuse can still be tripped by the gauge from hardware protections, even if the PF is disabled in settings (which it should not be) it will still blow the fuse (PTC)

If another PF occurred like SOTF then it should be in the black box recorder data. a .gg file would be helpful to verify settings.

Sincerely,

Wyatt Keller

Hello Wyatt,

you will get the gg.csv file via PN.

Regards,

Hans

Hello Hans,

I reviewed your .gg file and see the same settings you outlined.

Is there a secondary protector that could have blown the fuse? If multiple PFs and safety statuses are happening around the same time it may be difficult to delineate which one may have been part of the final PF. From the blackbox data it doesn't look like any of the PFs the tripped are set to blow the fuse.

Sincerely,

Wyatt Keller

Hello Wyatt,

Yes of course, we have BQ296103DSG as secondary protection. Yesterday, I found out that our suppressor diode (PACK+ Protection) was in short circuit state. This explains ASCD/ASCDL  entries by BQ40z50-R2. Surely the voltage dip, by short circuit has trigger BQ296103DSG voltage lockout.

I’m thinking about it to enable PF C Bit 6 (2LVL) in future.

Is my guess possible and this the correct option?

Regards,

Hans