• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 62 subscribers
  • Views 358 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.

TPS54478: possibility to control two converter units (EN) from one PGOOD.

Bart
Expert 6470 points
Part Number: TPS54478


Team,

Is it possible to control two TPS54478 units on EN from one TPS54478's PGOOD? Wouldn't be the current from two enables to one power good too high? Can´t find the current or voltage flows from EN in datasheet.

Based on the below graph from datasheet (page 15), it seems it works without pull-up resistor on PGOOD. 

 

And in pin specification, it is mentioned than there is some current source and pull up (page 4).

 

And in functional diagram, there could be seen some sources in EN.

 

 

 

  • 0
    TI__Genius 14876 points

    Hello Bart,

    We usually recommend as common practice to use a pull-up resistor on PG pin of Buck regulators if you intend to use it.

    Here, Power Good is an open drain MOSFET.. meaning if it is not connected via a resistor to a pull-up voltage then PG pin is left floating.

    But as you can see in EN pin characteristics, if you leave EN pin floating it will be enabled by the internal pull-up current source.

    Then it is up to you which option you prefer, both options are fine.

    Thank you!

    Regards,
    Dorian