• State TI Thinks Resolved
  • Locked Locked
  • Replies 2 replies
  • Answers 1 answer
  • Subscribers 65 subscribers
  • Views 138 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.

BQ25750: Power Bank Application - Multiple MOSFETs Query between BQ76942/BQ25750

Apurva Singh
Prodigy 10 points
Part Number: BQ25750
Other Parts Discussed in Thread: BQ76942, BQ25756

Tool/software:

Hi Team,

Attached is an image showing the block diagrams of two ICs used in our system. Our project is a power bank with a 240 Whr capacity, configured with a 5S4P cell arrangement. Each cell has a capacity of 3350 mAh.

I am trying to charge the system with a 100W input, as depicted in the image.

The ICs we are using are:

  1. BQ25750 - Charger IC
  2. BQ76942 - AFE IC

I have a few queries:

  1. The BQ76942 recommends using multiple MOSFETs in the power path, specifically in a parallel configuration for both CHG and DSG FETs. However, this configuration is not applied in the BQ25750 IC, where only a single MOSFET is used. Why is there a difference in the MOSFET configuration between the AFE IC and the Charger IC while they are using similar kind of power paths?
  2. What are the calculations or considerations behind choosing these MOSFETs?
  3. Are the multiple MOSFETs used for reducing power dissipation/Losses?
  4. What is the specific purpose of using multiple MOSFETs in the AFE IC?

Thank you,

Apurva
Senior Embedded Hardware Engineer

  • 0
    TI__Mastermind 19660 points

    Hello Apurva,

    Thanks for working with this. I'm the applications engineer for the BQ25756. I can answer question 2.

    2. For the BQ25750, be sure to select FETs with a high SOA. We found the AON6276 works well for the power path switchover. You can check the Power MOSFETs Selection and ACFETs and BATFETs Selection sections in the datasheet.

    I'll loop in the battery monitor experts to help answer the rest of your question.

    Best Regards,
    Ethan Galloway

  • 0
    TI__Expert 4320 points

    Hello Apurva,

    I am not the expert on chargers so I couldn't tell you why the charger IC doesn't recommend multiple MOSFETs. For BQ76942, multiple MOSFETs are used for its current capabilities and heat dissipation. Having multiple MOSFETs in parallel allows the distribution of current. This is ideal for high current applications and lowering the MOSFETs temperatures.

    Best regards,

    Thomas Rainey