BQ40Z80: Part Recommendation

Dajon McGill

Part Number: BQ40Z80
Other Parts Discussed in Thread: BQ78350-R1A, BQ76930, BQ34110, BQ34Z100-G1, BQ76942

Hello Team,

I have a customer that is working on a UAV that requires a smart battery. They have an initial design based on the BQ40Z80. It was designed before they knew their power requirements. The BQ40Z80 is not working for them due to currents exceeding 100A and tripping the overload in discharge protection.

Do we have another fuel gauge that potentially uses a smaller value shunt and is meant for higher currents?

Best,
Dajon McGill

over 4 years ago

0 Matt Sunna over 4 years ago

TI__Guru* 81034 points

Hi Dajon,

This video shows how current scaling can be used for this device: https://www.youtube.com/watch?v=cg5sWXx5Srg

Are you able to current scale?

Best regards,

Matt

0 Dajon McGill over 4 years ago in reply to Matt Sunna

TI__Expert 6951 points

Hi Matt,

I appreciate the help!

The customer is aware of the scaling factor. The problem is the hardware protections (Short circuit in discharge and Overload in discharge). These can't be disabled and are based on the voltage across the shunt. Any suggestions?

Best,
Dajon McGill

0 Matt Sunna over 4 years ago in reply to Dajon McGill

TI__Guru* 81034 points

Hi Dajon,

I was also going to point to the BQ76930 + BQ78350-R1A as another option, but this faces the same issue in that the short circuit protection cannot be disabled so the shunt needs to be selected to avoid triggering the protection for the worst-case expected current.

Another option that provides some more flexibility is the BQ76942 where the short-circuit protection is more programmable and can even be disabled if needed. This is a battery monitor that could be used along with a top-of-stack gauge like the BQ34Z100-G1 or BQ34110. There is a video series that give an overview of this device here: https://training.ti.com/training-series-bq76952-bq76942-3-16s-3-10s-battery-monitors

TI Reference Design that shows how a top-of-stack gauge can be used with a battery monitor IC: https://www.ti.com/tool/TIDA-010030

Regards,

Matt

Power management

Power management forum

BQ40Z80: Part Recommendation