• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 1 answer
  • Subscribers 63 subscribers
  • Views 590 views
  • Users 0 members are here
Support feedback
Options
Options
Related

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.

BQ25570: System Load on VSTOR

Christian Grau28
Intellectual 375 points
Part Number: BQ25570

Considering Figure 21 the sentence "VBAT connected to VSTOR to allow charging" suggest, that the system load is supposed to be connected to VSTOR.

 All drawings found in the datasheet have the system load connected to VOUT (e.g. Figure 24).

What does VBAT connected to VSTOR mean?

Kind regards

Christian

  • 0
    TI__Genius 12485 points

    Christian,

    In some applications I have seen the MCU be present on VOUT and a display / radio be connected on the VSTOR where you can make use of a headroom with regards to voltage. You could have more than one system load on this type of application. 

    Could you share more details on your application?

    Regards,

    Gautham

  • 0 in reply to Gautham
    Intellectual 375 points

    Gautham,

    Thank you for your reply. I see the idea. In my setup I want to use the BQ25570 to charge a Supercap (1F/5.5V) from a rather weak solar cell (max 2V, some uA to max 50mA). 

    From the supercap the BQ provides power to a 2.5V microcontroller.

    In my application I would probably be connect directly to the supercap which resides at the VBAT port rather than VSTOR. In order to have the system starting up quickly I only use a 100uF at the VSTOR pin.

    Do you see any disagreement in this?

    Kind regards

    Christian

  • 0 in reply to Christian Grau28
    TI__Genius 12485 points

    Christian,

    that sounds reasonable. However, the cold start will be a very slow phase and having the cap on the VBAT will help. 

    What is the voltage on the cap? is it actually 5.5V or are you using a couple of them in series?

    regards,

    gautham