BQ21061: When VBUS is plugged off, I2C error occures

Naoya Inoue

Part Number: BQ21061

Tool/software:

Hello,
Now I'm writing a program to control BQ21061 and I found a strange phenomenon.
When VBUS is plugged off, suddenly I2C read function starts to return I2C error.
This problem started from just yesterday but before it worked noramally.
What cause could be possible? if someone nows about this phenomenon, tell me how to solve it.
Thanks

9 months ago

0 Juan Ospina 9 months ago

TI__Mastermind 18365 points

Hi,

Can you confirm what the voltage of the Battery and the /LP pin is when the VBUS is removed?

Best Regards,

Juan Ospina

0 Naoya Inoue 9 months ago in reply to Juan Ospina

Prodigy 30 points

Hi,

/LP is always L

Are there other causes or way to solve?

0 Juan Ospina 9 months ago in reply to Naoya Inoue

TI__Mastermind 18365 points

Hi,

If /LP is always low, then when the input VBUS is removed and the device is operating only off Battery power, the device enters low power state. In low power state I2C communication is disabled. If you want to have I2C communication during battery only mode then the /LP pin will have to be pulled high.

Best Regards,

Juan Ospina

0 Naoya Inoue 9 months ago in reply to Juan Ospina

Prodigy 30 points

Thank you for your advice,

So it means /LP low makes Low power mode disable and /LP High makes Low power mode enable?

If /LP is always fixed to H, I2C communication continues normally?

I'll change /LP setting and try it again.

Thanks,

+1 Juan Ospina 9 months ago in reply to Naoya Inoue

TI__Mastermind 18365 points

Hi Naoya,

To clarify /LP low is Low Power mode Enabled. /LP High is Low Power mode disabled.

Low Power mode prevents I2C Communication.

Naoya Inoue said:
If /LP is always fixed to H, I2C communication continues normally?

This is correct.

Best Regards,

Juan Ospina

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BQ21061: When VBUS is plugged off, I2C error occures