• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Subscribers 63 subscribers
  • Views 45 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.

TPS25980: Unreliable output at 95% of Ilim

Jesse van der Zouw
Expert 1035 points
Part Number: TPS25980

Tool/software:

I am using TPS259807ONRGER to drive a strip of digital controllable LEDs.

Current limit is 5.5A, but at around 5.1A the output starts to trip, causing the LEDs to flicker

The weird thing is that when increasing further to 5.2 to 5.4A, output will stabilize again.

After 5.5A the output current limit will start tripping as expected.

I suspect premature overcurrent tripping due to noisy current profile, but don't know why that is not the case anymore at 5.2 to 5.4A.

Increasing Ctimer improves the situation greatly but does not seem to solve it fully.

I am looking for guidance on how to diagnose the flickering source and how to solve it.

Schematic:

Layout (4 layer: G/S/S/G)

 

Thanks in advance,
Jesse

  • 0
    TI__Mastermind 38335 points

    Hi Jesse,

    The issue you mentioned above is most likely due to noise in your system. It cannot be wire drop as it is working fine at 5.2A-5.4A. Do you have any other cap other than C2 and C13 in power path? What is driving the power path?

    • Increasing the itimer should help
    • Increasing the Cin should help
    • Getting waveform of Vin, Vout, current and Itimer pin will help here. You can also probe IMON pin instead of probing current directly.

    Best Regards,
    Arush

  • 0 in reply to Arush Gupta
    Expert 1035 points

    Thanks for the response Gupta. Did some more investigation and also noticed I miscalculated Rimon by factor 10. Adjusted that, increased itimer and added some extra output capacitance. Solution works stable now. Thanks.