• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 63 subscribers
  • Views 601 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.

Questions on the bq24250 charging with less than 100mA

Chris Neugebauer
Prodigy 20 points

I am running with a supply that has variable power capabilities. 

1. I need to be able to run the charger at between 50 - 100mA charge limit.

- I see in the register in section 9.6.4 of the spec that it can be set to 50mA.  Could this also be set for the ILIM?

- Is the 50mA coming from the LDO?

2. I also see the VDPM pin will cause the current limit regulate below set point .   I love this ..... however (question(s))

-  I see that the termination current setting would be the set point at which if regulation on the VDPM is not working it will then terminate charge. Is this correct?

-  The ITERM seems to be defaulted to with all 0's the spec does not explicitly say what this means.  It is states that it is defaulted to 50mA in I2C mode but I am not seeing how from your truth table.  Clarity please.

3. From question 1 .  To clarify from spec section 9.6.4 . If I was to set the current externally to 25mA (if possible) Iterm would be ~ 23mA? 

4. If current is to low to charge I am assuming that either the energy is combined with the battery to power the load?

  • 0
    TI__Guru**** 166176 points
    Regarding 1, charging at currents lower than specified in the 500mA minimum in elec specs table are not warrantied. The register resolution is down to 50mA with a starting offset of 500mA. The LDO does not provide charge current.
    Regarding 2, if VDPM is active, termination is disabled. In standalone mode, ITERM is 10% of ISET. In host mode, ITERM is set by the register and has a 50mA default offset.
    Regarding 3, in host mode, you cannot set ITERM less than 50mA. In standalone mode, termination current accuracy is not warrantied and will be much wider than 10% of ISET +/- 10% accuracy.
    Regarding 4, the power path feature allows the load to be powered from the input source when available, supplemented by the battery when necessary.