BQ25890: Shipping mode condition

Hirokazu Takahashi

Part Number: BQ25890

Dear Support team,

When BATFET_DIS is set from 0 to 1 at USB_VBUS active, it does not immediately enter the shipping mode, but when USB_VBUS is turned off, it seems that it enters the shipping mode.
Is it correct phenomenon?
Is it necessary to turn off USB_VBUS for proceeding to the shipping mode?

Best Regards,
Hirokazu Takahashi

over 5 years ago

0 Jeff F over 5 years ago

TI__Guru**** 165766 points

Hi Takahashi-san,

BATFET_DIS bit from 0->1 is immediate unless the BATFET_DLY bit is used to add tSM_DLY=10-15s delay.

Regards,

Jeff

0 Hirokazu Takahashi over 5 years ago in reply to Jeff F

TI__Expert 8420 points

Hello Jeff-san

Thanks for your reply.
What should we check for clarifying the gap?

Best Regards,
Hirokazu Takahashi

0 Jeff F over 5 years ago in reply to Hirokazu Takahashi

TI__Guru**** 165766 points

Takahashi-san,

With VBUS applied and charge enabled, disable BATFET and confirm that charge stops and measurement BAT voltage.

With VBUS not applied, place a load on SYS, disable BATFET and confirm that no current flows to the load and measure BAT voltage.

Regards,
Jeff

0 Ning T over 5 years ago in reply to Jeff F

TI__Guru 57321 points

Hi,

We haven’t heard back from you for a while, the thread is considered solved and closed.

Thanks,

Ning.

0 Hirokazu Takahashi over 5 years ago in reply to Ning T

TI__Expert 8420 points

Hello Jeff-san

Sorry, we haven't be clear for this yet.
In case of "VBUS" non-active condition, the voltage of "SYS" is immediately will drop after setting "BATFET_DIS" to 1.
The voltage of "SYS" is kept to active if "BATFET_DIS" will be set "1" while "VBUS" is active. "SYS" will be dropped down after making "VBUS" off.
Is this phenomenon is correct?

BQ25890 ship mode.pdf

Best Regards,
Hirokazu Takahashi

0 Jeff F over 5 years ago in reply to Hirokazu Takahashi

TI__Guru**** 165766 points

Hi Takahashi-san,

If no VBUS and BATFET_DIS=1, SYS falls immediately. There is a "delay BATFET turn off" bit that we recommend be used in order to prevent SDA, SCL, if pulled up to SYS, from collapsing during the I2C transmission.

If VBUS is applied and BATFET_DIS=1, the buck converter still provides a SYS voltage. If the load on SYS is too high for the charger's input current limit or adapter power, then SYS will fall because the battery is not available to supplement.

Regards,

Jeff

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BQ25890: Shipping mode condition