BQ77915: Seperation of PowerGND from Cell-0 Connection.

Rico Schmitt84

Part Number: BQ77915

I would like to use the BQ77915 for a BatteryPack with higher Loads. We will need a separate connection from Battery Minus for Power- and Cell0 on the Board. Otherwise we will measure the voltage drop over the cable connecting battery- to the BMS.

VSS of the BQ will be connected to PCB Ground. The Question is where to connect the PCB Ground.

I see two possibilities.

1) Connect PCB Ground to the BATTERY minus power connector -->> Cell0 VC0 Pin Voltage will be slightly above/below VSS, depending on the current polarity.

2) Connect PCB Ground to the Cell ) Measurement Line -->> SRP, SRN Pins will be slightly above/below VSS depending on the current polarity.

Maybe someone can give a thought on that. Thanks!

over 4 years ago

0 Shawn Hinkle over 4 years ago

TI__Expert 7455 points

Hi,

I would recommend using the first configuration listed. But make sure to thoroughly test the board for any affects to the functionality.

0 Rico Schmitt84 over 4 years ago in reply to Shawn Hinkle

Prodigy 30 points

Thanks for your reply shawn. Is there any reason for your preference or just stomach feeling?

0 Shawn Hinkle over 4 years ago in reply to Rico Schmitt84

TI__Expert 7455 points

Hi,

The disadvantage you listed for the second solution seemed worse. VSS isn't used for any of the protection logic, but the SRP and SRN pins are. I would avoid changing pins related to the device's functionality if possible.

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BQ77915: Seperation of PowerGND from Cell-0 Connection.