BQ27Z746: Not moving out of shutdown mode when charger is present.

Hi Jesse,

Any of the exit conditions shown below should exit SDM. have you tried all of these?

Best Regards,

Jackson

Hello Jackson,

Thanks for the reply. Referring to the Exit Status, Vstartup is an enigma because  I cannot find what it is defined as anywhere in the documentation for the BQ27z746. The ENAB pin is tied low. There is no way to bring the cell voltage above Shutdown Voltage without replacing the battery because you cannot charge the battery because CHG and DSG bits are low. 

Hi Jesse,

I am taking a look inside the firmware right now to look for a root cause. I will reach out tomorrow with an update.

Best Regards,

Jackson

Jesse,

Is this an anomaly you are observing in one chip or do you observe the same behavior across multiple devices?

Best Regards,

Jackson

Hello Jackson,

The anomaly is happening across all of the devices produced(22). It seems that the voltage shutdown will recover when a charger is put on, but the auto-time shutdown will not recover when a charger is put on. We put a work around in that involves switching the modes at start up in firmware. This ensures the device can be reset when a charger is present because the MCU is powered and can send messages to the gas gauge. I still am confused about the vagueness of the reference manual and "Vstartup" which is not mentioned anyway in the documentation

Hi Jesse,

Glad that you found a workaround for the issues getting the device out of shutdown. I am reaching out to my team now to clear up the documentation regarding Vstartup to provide more clarity and avoid ambiguity.