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TPS62290: Buck Converter Issue – TPS62290DRVT (VIN = VOUT)

venkateshraja p
Prodigy 95 points

Part Number: TPS62290

Tool/software:

We are observing an issue where the input and output voltages are the same. We have cross-verified the feedback (FB) resistor network and performed impedance testing.

We also probed the SW pin using an oscilloscope and noticed that the switching is not functioning properly.

Kindly help us identify the possible root cause of this issue, as it is occurring on multiple boards.

Thanks,

Venkat

  • 0
    TI__Mastermind 26900 points

    Hello Venkat,

    thanks for reaching out in E2E.

    Could you please provide more details on the results of your FB resistor network analysis and of the SW pin signal? It would help to better understand the described device behavior.

    A possible root cause for such a behavior could be caused by bad soldering. If the FB pin is getting shorted to GND (thermal pad or via grounded MODE pin) then the device would operate in 100% duty cycle mode and VOUT would be very close to the VIN value and the SW signal would stop switching.

    Please let me know.

    Best regards,

    Andreas.

  • 0 in reply to Andreas Mueller
    Prodigy 95 points

    Hi Andreas Mueller,

    Thanks for your support, Here are our findings:

    • FB pin voltage: 1.1V

    • Feedback Resistor Values: R1 = 360kΩ, R2 = 180kΩ

    • SW Pin Signal: Constant DC voltage VIN (no switching observed)

    • FB Pin and MODE Pin: Is not short to GND

    • After replacing the buck IC with a new one, the converter operates correctly.

    We would like to understand: 

    • What are the possible root causes for repeated failure on multiple boards?

    • Why is the IC operating at 100% duty cycle with no switching signal?

    Thanks,

    Venkat

  • 0
    TI__Mastermind 26900 points

    Hello Venkat,

    thanks a lot for your feedback.

    Unfortunately I can not conclude on possible root causes of the observed behavior of the TPS62290.

    I think it is necessary to send one of these devices back to TI for analysis.

    Please work with your distributor to initiate a CPR (customer product return) process.

    Let me know if you have any questions.

    Best regards,