BQ77915: Failure of TI Part BQ7791501

Hello Rahul,

BQ7791501 has several different thresholds and delays for different protections versus BQ7791514.

From the schematic you have shared:

1. Q1 isn’t needed to protect the CHG Pin and FETs if you have D2 and D4, though we would recommend adding Q3 and R41 back for a faster turn-off for the CHG FETs.

2. Apologies for my previous comment. I see that you have BAT- connected to GND through VSS. Instead, a Schottky and Zener diode from VC0 to VSS can be more useful to add to protect the VC0 pin. Do you have a separate high current and low current path to BAT- as well?

Rahul Sharma said:

We are unable to analyze the reason of failure

Are any of the FETs or passive components damaged? Can you share the procedure/test they do when it fails?

Best Regards,
Alexis

Dear Sir,

We are using separate path for low and high current.

our concern is that failure rate of IC BQ7791501 is very high.

If we implement your suggestion put Schottky diode and Zener diode between VC0 and VSS, will failure rate reduced?

If not, please suggest RCA?

Thanks

Rahul Sharma

Hello Rahul,

As we do not know what is causing the failure, I cannot guarantee that adding the Schottky Diode and Zener Diode between VC0 and VSS will reduce the failure rate. Are any of the FETs or passive components damaged? Can you share the procedure/test they do before/when it fails? 

Best Regards,
Alexis

Dear TI Expert,

Except IC, No Passive component is damaged.

We require analysis.

why IC Failure rate is high?

Thanks 

Rahul Sharma

Hello Rahul,

Thank you for clarifying. Could you try making some of the changes to see if those help? If you want to return a unit for analysis, please follow this link for more information: Customer returns | Additional information | TI.com

Best Regards,
Alexis

Dear TI Expert,

Should i send complete product for analysis?

Thanks 

Rahul Sharma