• State TI Thinks Resolved
  • Locked Locked
  • Replies 5 replies
  • Answers 3 answers
  • Subscribers 63 subscribers
  • Views 190 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.

BQ24170: SCH review and balancing solution

Kailun Liu
Expert 3123 points
Part Number: BQ24170
Other Parts Discussed in Thread: BQ24105, BQ25672, BQ25887

Tool/software:

Hi Team, 

Can you help to review below sch? Does it support cell balancing? If not, do we have suggest alternative?

Besides, customer is wondering if there were any other 3S charging solution? 

Requirement: 3S1P, support power path management. 

Thanks!

  • 0
    TI__Guru**** 167196 points

    Hi Kailun,

    I do not see any obvious errors on the schematic.  I did not compute the ISET an OVPSET values.  Those can be checked using the xls at https://www.ti.com/tool/download/SLUC231. Although not required, we recommend the highlighted components below.  The input RC filters out hot plug voltage spikes. The 2 capacitors on the FET provide soft start for the input FET.

    The charger does not have a balancing feature.  You could add an external cell balancer plus protector like I2C controlled https://www.ti.com/product/BQ76905.  

    We have other 3 cell chargers including:

    1. BQ24105 standalone charger

    2. BQ25672 I2C controlled charger

    Regards,

    Jeff

  • 0 in reply to Jeff F
    TI__Expert 3123 points

    Hi Jeff, 

    Much appreciated for your reply! I would like to further check with you: 

    According to the chip design, I think it is necessary to drive the MOSFET gate through the ACDRV pin to control the MOSFET switch. However, the specified reference design places this at the source level of the two MOSFETs. I would like to ask if our design needs to be modified.

  • 0 in reply to Kailun Liu
    TI__Guru**** 167196 points

    Hi Kailun,

    Oops.  I missed that.  The CMSRC pin must be connected to the common source connection.

    Regards,
    Jeff

  • 0 in reply to Jeff F
    TI__Expert 3123 points

    Thanks Jeff, 

    How is chip control achieved if the CMSRC pin is connected to a common source?

    And do we have 3S charger support cell balancing? I remember BQ25887 could support cb but it is 2S.

  • 0 in reply to Kailun Liu
    TI__Guru**** 167196 points

    Hi Kailun,

    CMSRC pin provides a "gnd" node for the charge pump output at ACDRV. 

    TI BCP group does not have 3S charger with integrated cell balancing.  

    Regards,

    Jeff