• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 2 answers
  • Subscribers 62 subscribers
  • Views 140 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.

BQ24640: Datasheet Question

Gerald
Genius 9580 points
Part Number: BQ24640

Hi Experts,

Our customer is wondering about table 4 of the data sheet, and the ability to optimize these parameters when the sense resistor is changed. And if this inductor is part of the efficiency calculation within the system.

I can see that more information can be found in sections 8.2.2 and 7.3.2. I am also sharing the calculation tool for this device with the customer. If you have further inputs above the customer concern above, please let me know.

Also, do you think you could add something about the adapter supply current to the VCC pin and how the adapter supply current to the VCC pin was determined from the various components?

Thank you and best regards,
Gerald 

  • 0
    TI__Mastermind 33285 points

    Hi Gerald,

    The sense resistor and DCR of the inductor definitely affect the efficiency of the system. One thing to keep in mind about the sense resistor is that for the same current, higher RDSON yields greater sense voltage but higher loss. The lower the sense voltage, the less accurate the charge current is. See "Charge current regulation accuracy" in the EC table.

    Please see "Adapter supply current into VCC pin" with the third option in the EC Table for when VCC = 20 V and charging is happening.

    Regards,

    Mike Emanuel

  • 0 in reply to Michael Emanuel35
    TI__Genius 9580 points

    Hi Mike,

    Please see below for our customer feedback:
    "I was wondering if you might be able to provide more insight as to what additional on-board components impact the …”"Adapter supply current into VCC pin" with the third option in the EC Table for when VCC = 20 V and charging is happening.” … I understand the nominal values present in the table but would like to further discuss these currents at different VCC values, and see if there might be a way to optimize this value to a lower supply current to VCC pin."

    Thank you for your time.

    Best regards,
    Gerald

  • 0 in reply to Gerald
    TI__Mastermind 33285 points

    Hi Gerald,

    Providing same answer as asked by Elora in private message. Please use this thread only to communicate this more clearly.

    What charge current are you looking for? This device is not suited for low charge current below 1 A and is designed to mostly operate between the 2 A to 10 A range.

    As for VCC I do not believe we have this data, mostly because the application for this device is in the 10s of Watts and the VCC loss is negligible compared to the total power. 

    However, I would not recommend this part for 50 mA charge current application as the BOM is significant due to this being a charge controller. The switching losses will become more significant due to the lower amount of power being transferred.

    Regards,

    Mike Emanuel