• State
  • Locked Locked
  • Replies 3 replies
  • Subscribers 64 subscribers
  • Views 75 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.

TPSM82866A: Start up time issue in case voltage scaling

Shoo Saga
Intellectual 1621 points
Part Number: TPSM82866A

Hi Team,

My customer is using TPSM82866A. and have a issue. They use TPSM82866A with DAC as voltage scaling. then the start-up time is only 300us. Do you have any solution for that?

Adding RC filter on EN pin could be the solution?


Thanks,

Shoo

  • 0
    TI__Guru*** 144230 points

    Hi Shoo,

    Can you share your circuit and a waveform that shows the behavior?  I don't quite understand it.

    Thanks,

    Chris

  • 0 in reply to Chris Glaser
    Prodigy 100 points

    Dear Chris Glaser ,

    I have attached the points I would like to confirm.

    I want to use the softstart function with a resistor attached to FB because I want to change the output voltage with the specifications I want to do now. Vramp was 900us at 5V, but Vramp was 300us at 1.8V.

    Is it possible to make Vramp about 1ms at 1.8V due to inrush current?

    Also, how should I set Vset/MODE to set it?
    TPSM8266A_confierm_softstart.pptx

  • 0 in reply to user5034648
    TI__Guru*** 144230 points

    Hi Shoo,

    Thank you for the data.  The graph shows a ~1msec SS time for a 5V output?  This is correct.

    Can you show the same graph for the 1.8Vout?  Was that one showing 300 usec?  The SS time should not change with Vout.

    Since you want to adjust Vout through the FB pin, VSET/MODE should be tied to GND or Vin to set it at a logic high or low.

    Chris