• State Resolved
  • Locked Locked
  • Replies 7 replies
  • Answers 3 answers
  • Subscribers 62 subscribers
  • Views 262 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Original question:

BQ24190: Used only as a charger

BQ24192I: Charging a battery with another battery

Nir Dvash1
Intellectual 470 points
Part Number: BQ24192I

Hello,

I was wondering if it is possible to use the BQ24192L to charge a low capacity battery from a larger capacity battery and if so, how would one achieve that?

(Note: The larger capacity battery is removable and will be charged externally to this system)

Thank you,

Nir.

  • 0
    TI__Mastermind 49361 points

    Nir,

    The maximum charge current of the BQ24192I is 4.5A. If the Battery Charging Profile on Figure 14 of the d/s meets a larger capacity battery charging requirement, it should work.

    Thanks,

    Ning.

  • 0 in reply to Ning T
    Intellectual 470 points

    Hey Ning,

    Thanks. Do I need to boost the voltage of the battery to 5V before connecting it to the BQ's VBUS input?

    Nir. 

  • 0 in reply to Nir Dvash1
    TI__Mastermind 49361 points

    Nir,

    The device may only work in charge mode or boost mode, not in both modes at the same time. If valid VBUS is present, the device will charge the battery, if the battery is present and boost mode conditions are met, the device may support boost output at VBUS.

    Thanks,

    Ning.

  • 0 in reply to Ning T
    Intellectual 470 points

    Hey Ning,

    I think I did not explain my intention clear enough. Please see my hand drawing here. I am asking

    if I need the DC/DC block between the large battery and the BQ IC. Is the 3.7V coming from this battery enough to

    charge the small battery using the BQ or do I need to boost it to 5V in order to get the BQ to work?

    Nir.

  • 0 in reply to Nir Dvash1
    TI__Mastermind 49361 points

    Nir,

    The input voltage range for BQ24192I is 3.9V to 17V and the VBUS pin voltage must be higher than the batter charge voltage limit in order to change the battery in full. If the large battery output is only 3.7V, it is necessary to boost the voltage up as the VBUS of the charger.

    Thanks,

    Ning.

  • 0 in reply to Ning T
    Intellectual 470 points

    Hey Ning,

    Thank you, I see. I think that in this case I will create a 7.2V battery as the charging battery (2S) to avoid the need for a boost stage.

    BTW, while playing with the different charging current and current limits settings of the BQ I have now set it to 2Amps charging current and

    it does that but the device gets very hot, I can get a burn on my finger if I touch it. Is this normal or do you think something is wrong?

    Nir.

  • 0 in reply to Nir Dvash1
    TI__Mastermind 49361 points

    Nir,

    It is critical that the exposed power pad on the backside of the IC package be soldered to the PCB ground. Ensure that there are sufficient thermal vias directly under the IC, connecting to the ground plane on the other layers. Please check if the exposed pad is soldered down correctly. Please refer to 12 Layout and Figure 52. Layout Example Diagram on the d/s for the details.

    Thanks,

    Ning.