• State
  • Locked Locked
  • Replies 3 replies
  • Subscribers 62 subscribers
  • Views 473 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.

Multiple Schottky Diodes in TPS54040 Design

Justin Clacherty
Prodigy 170 points


I'm just playing around with SwitcherPro at the moment and one of the designs it came up with had multiple Schottky diodes in it.  I presume these are supposed to be put in parallel and they're being suggested to meet the peak current requirements.  Can anyone confirm that's the case?

Justin.

  • 0
    TI__Guru**** 191445 points

    I've never seen that before.  Are you using the online version or the download?  Can you please post the conditions you used and possibly a screen shot of the results?

  • 0 in reply to JohnTucker
    Prodigy 170 points

    I don't think I've seen it in the initial design that SwitcherPro gives me, it only happens once you start changing parts.  If you choose a different Shottcky Diode that doesn't have the current requirements it tells you you need more.  Click proceed and it just puts in the number it thinks you need.  I can't say I've ever designed a switcher with 2 catch diodes before which is why I was asking the question.

    To replicate just do a design in either the online or desktop versions with the following parameters:

    Vin(min) = 8V

    Vin(max) = 28V

    Vout = 3.3V

    Iout = 0.3A

    It'll do a design which will have a ZLLS350 in it.  Click on it to change.  Pick something else (SDM20U30LP) and click apply.  It'll say you need two to meet current requirements.  Click proceed and it's done.

    I was trying to pick a different catch diode because the design it comes up with has a max temp on the diode of 82 degrees which is a bit hot for my liking.

    Justin.

  • 0 in reply to Justin Clacherty
    TI__Guru**** 191445 points

    OK, I can beleive that.  I have never tried the catch diode, but I know for a fact if you pick an output capcitor that is not sufficient, it will suggest a larger quantity to meet the rating requirement.  I bet teh software uses the same checking routine for the diode.  I will check w/ the software team to be sure and post back later today with the definitive answer.