BQ40Z80: bq40z80 DFET

Ian Wang

Part Number: BQ40Z80

Hi Sir,

We met DFET will ON-OF-ON-OFF when bq40z80 battery voltage too LOW. and we confirm is trigger by AFE watchdog timeout.

May I know if AFE watchdog relative with input voltage of pack pin?

Can I say if increase battery voltage will avoid the issue?

Thanks, Ian.

0 Andy Liu (BMS) over 5 years ago

Hi Ian,

How about the CHG FET? Does it turn on and off as well? Is the lifetimes enabled?

I would suggest you adjust the stack voltage and see if it happens in a particular voltage.

Andy

0 albert liang over 5 years ago in reply to Andy Liu (BMS)

when stack voltage down to 16v, it is easy to occur DFET ON-OFF-ON, however 18v does not.

Is it related to the resistance of R1034?? (Currently, R1034 uses 2K instead of 10K).

CFET gate signal is blue, pack+ voltage is red, the waveform implies that DFET and CFET are on-off-on at the same time.

the watchdog timeout default is 2sec?, i saw the waveform on-off gap is 2sec.

please assist me...., thank you.

0 Andy Liu (BMS) over 5 years ago in reply to albert liang

Hi Ian,

Can you send me the customer's srec file? I will try to reproduce the same issue in the lab. Thanks.

Andy

0 albert liang over 5 years ago in reply to Andy Liu (BMS)

as attached file. thank you

0 Andy Liu (BMS) over 5 years ago in reply to albert liang

Hi Albert,

I already had a call with Ian and he will work with you again on this issue.

Andy

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