BQ20Z655-R1: DSG FET doesn't turn off at end of discharge

Sean Fahey

Part Number: BQ20Z655-R1

Hi,

During discharge, the discharge FET is supposed to turn off once it approximately reaches the term voltage, but it does not. I am able to turn the FETs on and off using the FETcontrol command.

Is there something in my data flash values that isn't set correctly or could it be something with the BMS board itself?

over 2 years ago

0 Shirish over 2 years ago

TI__Guru 57697 points

Hello Sean,

The FET does not turn off based on terminate voltage.

The FET will turn off based on protection settings. Check 1st level safety CUV parameters to see if the safety conditions are being met.

0 Sean Fahey over 2 years ago in reply to Shirish

Prodigy 120 points

But shouldn't the FET connected to the DSG pin on the BQ20Z655 open once the voltage reaches a certain point during discharge?

0 Shirish over 2 years ago in reply to Sean Fahey

TI__Guru 57697 points

Hello Sean,

The host is expected to shutdown and stop drawing current as it reads data from the gauge. The gauge will cut off power only when protection is triggered. This is by design, otherwise the host does not have a chance to save data.

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BQ20Z655-R1: DSG FET doesn't turn off at end of discharge