• State TI Thinks Resolved
  • Locked Locked
  • Replies 4 replies
  • Answers 1 answer
  • Subscribers 61 subscribers
  • Views 515 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.

TPS54531: please help check why the output of TSP54531 is unstable,

user5324035
Intellectual 290 points
Part Number: TPS54531
Other Parts Discussed in Thread: TPS56637

As below picture, we designed a circuit with 2pcs TPS54531, which input power is 5V or 12V ,and output power is 4V.

when we received the PCB , we found the out power of TPS54531 is unstable, changing from 2.6V to 3.6V, could you help have a check for this issue? thanks a lot.

  • 0
    Intellectual 290 points

    Below picture is the curve of output power

  • Former Member
    0 Former Member in reply to user5324035

    Hi,

    Could you please clarify the condition in the waveform you showed? What is the input voltage? What is the loading? Does 12V input voltage works normal?

    Thanks.

  • 0 in reply to Former Member
    Intellectual 290 points

    Thanks Bruce,  I update the picture of curve, and the issue need be updated as below:

    1) if set the input power below 5.2V, the curve of output power will same as the forward attached picture.

    2) if set the input power above 5.2V , the output power will be OK， 4V and stable.

    so we think the issue should caused by the efficiency of this circuit,  maybe caused by Circuit matching?

  • Former Member
    0 Former Member in reply to user5324035

    Hi,

    TPS54531 is a non-sync converter and cannot support large duty applications actually. You can add a diode from Vout to BST or use a sync converter like TPS56637 for this 5V-4V application.

    For detailed explanation, please refer to the same question from 

    Please let me know if any further support needed.

    Thanks.

    Bruce