BQ40Z80: The aging experiment caused the chip to fail to communicate

Dear Wyatt

Thanks your reply .

Below is TS lines waveform .

We increase the PBI  capacitance to 10uF , the IC still could not conmunication or turn on the CHG & DSG driver . 

Dose the IC enter Emergency FET Shutdown?

Hello Gabriel,

Is this TS waveform from the failed pack, or is this from a good pack? If it is the bad pack this indicates the firmware is still running. Can you outline what the aging test is?

Just increasing the capacitance on PBI will not recover the gauge, it may help with overall performance of the gauge with multiple FETs in parallel.

In emergency shutdown the gauge would still communicate with the EV2400 or host. 

Sincerely,

Wyatt Keller

Hi Wyatt

The aging test means  to repeatedly charge and discharge the installed Pack.

We replaced it with a new good IC and found that the same bad phenomenon appeared the next day. The TS pin had a pulsing of about 250ms, unable to communicate, and the IC could not be charged or discharged. 

This is our .gg file ,pls help to check  if this setting is possible.

d1062.gg.csv

Hello Gabriel,

If the TS pin is still pulsing on the failed pack this indicates that the firmware is still running, so the gauge should still be recoverable. Can you share the TS pin waveform from scope capture?

Sincerely,

Wyatt Keller

Dear Wyatt

Yes ,the TS pin still pulsing , below is the TS pin waveform : 

Dear Wyatt

How to let the gauge out of resting constantly  mode ?

We stuck in this problem and don't know how to get started.

Hello Gabriel,

You cannot recover the gauge once it has entered this mode. You must ensure the voltage on the TS lines do not exceed the absolute maximum.

Can you confirm with a good unit that the waveforms are indeed different? It's hard to tell exactly what is happening in that capture and I want to ensure this is the root cause.

Sincerely,

Wyatt Keller

Dear Wyatt

Thanks for reply ,below is the good unit TS1 & TS2 waveforms . Some times TS1 or TS2 will pulsing twice .

Dear Wyatt

Yes ,for the failed unit ,the TS pin have a very close double pulse ,we test new good unit  but could not find any abnormal pulse ,could u give a suggstion how to test what could cause the BQ40Z80 failed . 

Abonormal pulse :

Normal pulse and normal pulse zoom in :

Hello Gabriel,

This confirms the failure from voltages above the absolute maximum on the TS lines. I would recommend adding additional protection on the TS lines (~10nF caps) and trying to capture any operation modes where noise could be getting coupled to the TS lines.

Are you able to share the layout?

Sincerely,

Wyatt Keller

Dear Wyatt

this is pcb file 

Hello Gabriel,

Wyatt is out of office and will reply after he returns on Monday

Hello Gabriel,

I do not have the software to view the .PCB file shared. Please share the files in Altium formats or share the viewing software.

Sincerely,

Wyatt Keller

Dear Wyatt

Sorry to update late ,we just have a PDF version of pcb layout . Could u help to check ?

Now we send to customer 30pcs sample to test again ,customer found 4pcs of 30pcs good sample failure immdely when power on when add battery pack .