BQ25798: Shut down and ship mode

Nan Liu

Part Number: BQ25798

For all the BQ25xxx charger ICs, there is a shutdown mode and ship mode. For the ship mode as datasheet described, with only adapter input source is off, the IC will turn off both the BATFET inside the IC and the external ship FET, then the IC still keep the I2C alive, my question is, by cutting off both power source, where the power would come from to keep the IC itself alive ? If there is no source can keep it alive, what is the difference between the shutdown mode and ship mode?

over 1 year ago

0 Jeff F over 1 year ago

TI__Guru**** 166576 points

Hi Nan,

In ship mode with external shipFET, BATP pin is connected to the battery and consumes nA power to keep I2C alive. Please note that the internal BATFET cannot be turned off as it has a body diode from BAT to SYS.

Regards,

Jeff

0 Nan Liu over 1 year ago in reply to Jeff F

Prodigy 110 points

Hi Jeff,

Thank you for your answer. But this is not what the datasheet says:

And see the condition for this ship mode, it is confused.

0 Jeff F over 1 year ago in reply to Nan Liu

TI__Guru**** 166576 points

Hi Nan,

I will add to the list of datasheet changes to remove "turn off BATFET".

Regards,

Jeff

0 Nan Liu over 1 year ago in reply to Jeff F

Prodigy 110 points

even the BATFET is still on, but as long as the external ship FET is turned off, the IC will lose the power anyway, how it can still alive to do anything ?

0 Jeff F over 1 year ago in reply to Nan Liu

TI__Guru**** 166576 points

Hi Nan,

BATP is connected on the battery side of the shipFET and pulls nA current to power the I2C engine.

Regards,

Jeff

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BQ25798: Shut down and ship mode