BQ25798: EN_OTG will auto reset after some seconds

Hi Zheng,

Zheng Tao said:

Below is my schematic. I also learn BQ25798 has a backup mode. But my schematic doesn't has RBFET and ACFET. So I can't use backup mode?

RBFET and ACFET are required for backup mode. Without it, the charger blocks backup mode by forcing EN_BACKUP = 0.

please refer 9.3.7.2 Backup Power Supply Mode.

Zheng Tao said:

After set the EN_OTG to 1, BQ25798 did output 5V by battery discharge. But after some seconds, the EN_OTG will auto reset to 0. Is it normal?

The WD timer is set to 40s which could cause the EN_OTG to be reset to zero. 

Best Regards,

Jibin 

Hi Jibin,

Thanks for reply.

In my user case, without backup mode. Can I make it work like below:

1, when charger source is not connected, decided by REG1B_Charger_Status_0 bit0 VBUS_PRESENT_STAT, set EN_OTG =1;

2, when charger source is connected, decided by REG1B_Charger_Status_0 bit0 VBUS_PRESENT_STAT, set EN_OTG=0.

And I need to set EN_OTG regularly to avoid WD timer trigger?

I tried to set EN_OTG regularly. But it still auto reset EN_OTG after some seconds.

Hi Zheng,

For that use case, I'd recommend enabling the DIS_ACDRV bit.

Best Regards,

Jibin

Hi Jibin,

After set the DIS_ACDRV bit, it still auto reset EN_OTG after 40s.