BQ3060: Purpose of grounding SMBus Lines

Heba Sattar

Prodigy 20 points

Part Number: BQ3060

Hello,

I am working on a BMS design with BQ3060 using the following design guide:

https://www.ti.com/lit/an/slua507/slua507.pdf?ts=1707167790800

I'm wondering why the SMBus lines are grounded in the schematic:

Thank you!

over 1 year ago

0 Jonny over 1 year ago

TI__Mastermind 24751 points

Hello,

Here the SMBus lines are not connected to ground, the circuitry here is for ESD protection.

Regards,

Jonny.

0 Heba Sattar over 1 year ago in reply to Jonny

Prodigy 20 points

However, the negative side of the battery pack is connected to the BQ29412DCTT GND pin and also earth ground.

0 Heba Sattar over 1 year ago in reply to Jonny

Prodigy 20 points

Also, What are these funnel like symbols representing? Is it a change in trace width for routing?

0 Jonny over 1 year ago in reply to Heba Sattar

TI__Mastermind 24751 points

Hello,

These "funnel like symbols" are representing a spark gap.

Regards,

Jonny.

0 Heba Sattar over 1 year ago in reply to Heba Sattar

Prodigy 20 points

And the SMBus lines are also connected to Earth ground

0 Jonny over 1 year ago in reply to Heba Sattar

TI__Mastermind 24751 points

Hello,

The SMBus lines are not connected directly to ground.

Regards,

Jonny.

0 Heba Sattar over 1 year ago in reply to Jonny

Prodigy 20 points

What's the recommended gap size for the spark gaps? And are there any other guidelines/recommendations for implementing this in a PCB? Thanks!

0 Jonny over 1 year ago in reply to Heba Sattar

TI__Mastermind 24751 points

Hello,

Please refer to the following E2E thread.

Regards,

Jonny.

0 Heba Sattar over 1 year ago in reply to Jonny

Prodigy 20 points

Thanks so much!

0 Jonny over 1 year ago in reply to Heba Sattar

TI__Mastermind 24751 points

You are welcome!

Regards,

Jonny.

Power management

Power management forum

BQ3060: Purpose of grounding SMBus Lines