BQ34Z100-G1: Communication and Full Sleep mode

Chen Jia

Part Number: BQ34Z100-G1

Hi:

We are using BQ34Z100-G1, and after the Full Sleep mode enabled to save power, we noticed that the IC communication will get interrupted (all registers are 1) every 10 seconds, which is consistent with the FS wait time. Before FS was set, the I2C communication was good.

Test conditions:

No current flow, I2C pulled up, I2C communication every 400ms, I2C rate 100kbps.

In BQ34Z100-G1 spec, it stated "The gauge exits the FULL SLEEP mode when there is any communication activity", but if the communication exists, will the IC falls into FS mode? And wake up immediately because of communication? And this FS caused the I2C interrupted?

Thank you!

Chen

over 2 years ago

0 Shirish over 2 years ago

TI__Guru 57697 points

Hello Chen,

You are correct. The communication results in wake up. The delay in communication is due to wake up time.

0 Chen Jia over 2 years ago in reply to Shirish

Intellectual 850 points

Hello Shirish:

How is going?

Thanks for your confirmation. So even the I2C is active, the IC will get into "Full Sleep" mode if no current flow.

Thank you.

Chen

0 Shirish over 2 years ago in reply to Chen Jia

TI__Guru 57697 points

Hello Chen,

The gauge will go to Full Sleep mode when conditions are met. When there is I2C communication it will exit FullSleep mode and enter normal sleep mode. Hope this adds more clarity.

0 Chen Jia over 2 years ago in reply to Shirish

Intellectual 850 points

Hello Shirish:

Thanks for clarification. For FS mode, the condition is just in Normal Sleep mode for 10s, and it doesn't care if any I2C communication exist. But when it falls into FS mode, any communication event will bring it back to normal sleep mode.

Is there anyway to avoid it falls into FS mode during communication, if FS is set?

Thanks.

Chen

0 Shirish over 2 years ago in reply to Chen Jia

TI__Guru 57697 points

Hello Chen,

The power states are automatically entered. I don't think you can force it into any specific power mode.

The host must wait 4ms before retry communication when it detects a clock stretch to avoid reading wrong values.

Power management

Power management forum

BQ34Z100-G1: Communication and Full Sleep mode