• State Resolved
  • Locked Locked
  • Replies 6 replies
  • Subscribers 64 subscribers
  • Views 404 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.

BQ76940: BQ76940 Schematic Review – Please Verify and Suggest Changes

Vandana D
Prodigy 140 points
Part Number: BQ76940
Other Parts Discussed in Thread: BQ76200, BQ78350,

Tool/software:

BQ76940-Q1_REV_1V0_21_10_2024.zip

"I have uploaded a ZIP file containing the schematics developed for the BQ76940 chip. Please verify the design and notify me of any necessary changes. Thank you."

  • 0
    TI__Genius 17835 points

    Hello Vandana,

    Please give me some time to review your schematic.

    Best Regards,
    Alexis

  • 0 in reply to Alexis_H
    TI__Genius 17835 points

    Hello Vandana,

    Do you mind sharing a pdf image of your schematic? I do not have the software to access the files you shared unfortunately.

    Best Regards,
    Alexis

  • 0 in reply to Alexis_H
    Prodigy 140 points

    3034.BQ76940-Q1_REV_1V1_25_10_2024.pdf
    Hello Alexis,

    I have attached the schematic pdf of BQ76940 IC, Please do review it, and suggest the necessary changes to it.

    Thank you.

    Regards,

    Vandana

  • 0 in reply to Vandana D
    Prodigy 140 points

    Hello Alexis, 

    Could you please provide an update on the schematic review that I previously attached?

    Thank you.

    Regards,

    Vandana D

  • 0 in reply to Vandana D
    TI__Genius 17835 points

    Hello Vandana,

    Thank you for your patience. After reviewing your schematic for the bq76940 and the bq76200, here are some comments/questions:

    • VC1's input filter capacitor should be connected to VSS directly. This can be seen in Figure 9-3. BQ76940 with BQ78350 Companion Controller IC of the datasheet and Figure 37. bq76940EVM Schematic Diagram AFE1 of the EVM User Guide.
    • Is there a reason you have 499kOhms after the CAP1 push-button for boot before C1? We typically recommend 3.01kOhms.
    • NFET for VC5x/C15/REGSRC, is not connected correctly. The source should be connected to REGSRC, whereas the drain should be towards C15.
    • I believe the CHG/DSG pins of the bq76940 should go in the CHG_EN/DSG_EN of bq76200
    • We typically recommend Cvddcp (capacitor of bq76200 VDDCP pin) to be 470nF
    • We recommend 10Mohms for the CHG/DSG/PGate Rgs instead of 1Mohm
    • For Rpchg, we typically recommend 1MOhm resistance as well
    • Can you explain why you have another diode and 100ohm resistor connected from the DSG pin to the PACK pin from the bq76200?

    The bq68350 is a gauge device which belongs to a different team. I would recommend opening a new thread to have them review that portion.

    Best Regards,
    Alexis

  • 0 in reply to Alexis_H
    Prodigy 140 points

    Dear Alexis,

    Thank you so much for all the inputs you’ve shared. That was really helpful and gave me great clarity moving forward. I truly appreciate the time and effort you took to support me.

    Best regards,
    Vandana D