BQ20Z655: FETs blocking

Franz Schellhase

Part Number: BQ20Z655

Hi team,

A customer has configured bq20z655 on a BMS board and equipped it with new cells. Unfortunately the two FETs on the BMS are blocking, i.e. Ithez cannot charge or discharge the battery. Thez suspect an error in the flash data, because the flags TCA and TDA are set. I can send you the GG-file of their application for checking it? A 4s2p battery with NCR18650GA cells from Panasonic should be programmed with it.

Thank you,

Franz

over 5 years ago

0 Andy Liu (BMS) over 5 years ago

TI__Guru 52115 points

I ses that OperationStatus[QEN] is 0, which means the IT is not enabled. Try to enable IT first.

Andy

0 Marcus Mueller2 over 5 years ago in reply to Andy Liu (BMS)

Prodigy 80 points

Hello Andy,

thank you for your answer. I have done as you have written and enable the IT, after that the QEN-flag changes to high but the FETs are still off. It is not possible to measure the pack voltage on the battery pack connectors. The sys-press-pin is grounded, for your Information.

What could be the reason for this behavior ? Should I send more data of my BMS, which data do you Need ?

Best wishes, Marcus

0 Andy Liu (BMS) over 5 years ago in reply to Marcus Mueller2

TI__Guru 52115 points

Try to measure the TS1 or TS2 pin and see if you can see any pulse.

Andy

0 Marcus Mueller2 over 5 years ago in reply to Andy Liu (BMS)

Prodigy 80 points

I think I have found my mistake. I have thought that the old battery was configurated to a removable battery by the NR flag but I have checked the BMS board in Detail and the right configuration is none removable. Sorry but I have no schematic from the BMS board and it was not clear for me. After I have set the NR flag it is possible for me to meassure the pack voltage. Now I will go ahead with my tests. Thank you for your support.

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BQ20Z655: FETs blocking