• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Subscribers 63 subscribers
  • Views 178 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.

Original question:

TPS25762-Q1: 20V re-negotiation

TPS25762-Q1: 15V stability

Christopher Karle
Prodigy 50 points
Part Number: TPS25762-Q1

Tool/software:

I have a design using a TPS25762-Q1 with a maximum system power of 34W.  I have PDOs advertising 5V@15W, 9V@27W, 15V@34W, and 20V@34W.  The 15V rail seems unstable, with the switching circuit (audibly) resetting under a 30W load.  The other rails (including the 20V) are stable at this load, and lower loads produce similar results.  If 15V is first negotiate with no load and then the load is introduced, the 15V rail is stable.  

Any suggestions?

  • +1
    TI__Genius 10825 points

    Hi Christopher,

    Can you help me understand what you are using as a load?  Is it a power resistor?  E-load?

    It may also be good to have a waveform of SW1, SW2, and IOUT.  Also, as a general rule, the load should not try to operate at 34W until PS_RDY is received.

    Regards,
    Eric

  • 0 in reply to Eric Hartigan
    Prodigy 50 points

    I have an E-load device, which is always "on the bus".  It's odd that the other voltages do not exhibit this behavior, but yeah, I agree with your answer.  This should not be an actual problem in the field.  I'll mark this as resolved.