BQ25898: About CHRG_STAT register

Tsukui Yusuke

Guru 21930 points

Part Number: BQ25898

Hi,

Let me ask you about CHRG_STAT register transition in no battery condition?

If charging is performed while the battery is not connected, How does the REG0B CHRG_STAT register transition?
Is it correct to understand that CHRG_STAT becomes "11" after some time has passed when charging is started without connecting the battery?
Could you tell me the step where CHRG_STAT transitions when the battery not connected or deeply discharged?

Customer needs this information to consider how to process it in the MCU.

Best regards,
Yusuke

over 2 years ago

+1 Garrett Kreger over 2 years ago

TI__Mastermind 27780 points

Hi Yusuke,

Please refer to the FAQ linked below for expected behavior with no battery connected on the BQ25898.

https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1022791/faq-bq25890-why-does-the-led-connected-to-stat-pin-flashes-and-the-sys-voltage-unstable-when-battery-is-not-connected-for-bq25890-bq25890h-bq25892-bq25895-bq25895m-bq25896-bq25898-bq25898d-bq25898c-bq24190-bq24192-bq24192i-bq?tisearch=e2e-sitesearch&keymatch=bq25890#

To briefly summarize when no battery is connected the CHRG_STAT register will transition back and forth between 10b - fast charging and 11b - charge terminated. If the customer chooses to disable charge then CHRG_STAT = 00b - not charging.

When the battery is connected, but deeply discharged CHRG_STAT will indicate either 01b for precharge or 10b for fast charge depending on the voltage level of the battery. Precharge to fast charge transition is default set to 3V.

Best Regards,

Garrett

Power management

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BQ25898: About CHRG_STAT register