BQ25611D: BQ25611D-System voltage

switch

Part Number: BQ25611D

Hi Ti Team,

The BQ25611D currently used by the product has entered the PV Stage. The following problems have been confirmed during the test: 1) At present, when Min System voltage is set at 3.5V and the battery is not connected, the System cannot be started normally. After the Min System voltage is changed to 2.8V, the System can be successfully started without battery connection. In the figure below, Dc to Dc boosts/depresses to 3.8V for System use. I want to know why the change of Min System voltage, except Vsys from 3.68V to 2.98V, will there be any other impact on the function of Charger?

over 2 years ago

0 Ning T over 2 years ago

TI__Mastermind 49361 points

Hi,

The following FAQs should be helpful to your questions.

https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1021465/faq-why-vsys-does-not-start-up-normally-when-there-is-a-loading-on-the-sys-and-the-battery-is-not-present-for-bq25601-bq25601d-bq25606-bq25611d-bq25616-bq25616j-bq25618-bq25619-bq25600-bq25600d-bq25600c

https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1022795/faq-bq25601-faq-why-does-the-led-connected-to-stat-pin-flashes-and-the-sys-voltage-unstable-when-battery-is-not-connected-for-bq25601-bq25601d-bq25606-bq25611d-bq25616-bq25616j-bq25618-bq25619-bq25600-bq25600d-bq25600c

Thanks,

Ning.

0 switch over 2 years ago in reply to Ning T

Expert 2705 points

Hi Ning，

Thanks，Why does Vsys set to 3.5V fail to start the system while Vsys set to 2.8V can start the system without battery?

0 Ning T over 2 years ago in reply to switch

TI__Mastermind 49361 points

Hi,

We will get back to you on the next business day.

Thanks,

Ning

0 Garrett Kreger over 2 years ago in reply to Ning T

TI__Mastermind 22085 points

Hi,

Apologies for the delayed response. I attempted to recreate your observation on the BQ25611DEVM and was unable to replicate. Would you be able to provide some more information?

Can you please provide a scope capture of VBUS and VSYS during startup when Vsys fails to start, and then also VBUS and VSYS captures when you switch Sys_min from 3.5V to 2.8V? Also what is the current draw of your load attached to Sys output? If possible it would also be helpful to see system current at startup as well.

Best Regards,

Garrett

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BQ25611D: BQ25611D-System voltage