BQ40Z80: BQ40Z80 SMBus master mode and slave mode

CHUANLIANG ZHANG

Part Number: BQ40Z80

Hi TI team,

Our product has (1) smart battery system and (2) battery pack application as below:

For the smart battery system, BQ40Z80 uses SMBus1.1 with master mode. For battery pack application, MCU from DC fan configurates I2C as master and BQ40Z80 as slave mode.

My question is how to automatically switch BQ40Z80 from master to slave or from slave to master mode under condtion1 and condition2?

Hope to get your reply and thanks.

2 months ago

0 Nick Richards 2 months ago

TI__Genius 16626 points

Hey CHUANLIANG,

You would need to enable broadcast mode (BCAST) so that the gauge can communicate to the charger. The MCU will automatically be able to communicate to the gauge.

Regards,

Nick Richards

0 CHUANLIANG ZHANG 2 months ago in reply to Nick Richards

Prodigy 10 points

Hi Nick,

Maybe you do not fully understand our applications. I know that charger MCU can communicate with gauge if enable broadcast mode (master mode). In this case, if portable battery pack provides power to a fan system, MCU of the fan system should be a master device, how to achieve BQ40Z80 to a slave device?

0 Nick Richards 2 months ago in reply to CHUANLIANG ZHANG

TI__Genius 16626 points

Hey CHUANLIANG,

When communicating to the BQ40z80 (ex: wanting to get data from registers) the gauge will be in slave mode. That is the default behavior of the BQ40z80.

Regards,

Nick Richards

Power management

Power management forum

BQ40Z80: BQ40Z80 SMBus master mode and slave mode