Shop OBEX P1 Docs P2 Docs Learn Events
Best way to draw power from 14v AC? — Parallax Forums

Best way to draw power from 14v AC?

Professor ChaosProfessor Chaos Posts: 36
edited 2008-03-15 13:53 in General Discussion
I want to power a stamp and some associated logic circuitry off of a 14v AC line (model train application).

Would it be best to drop the voltage to ~ 7.5 by some rectifying diodes in series, then feed that into a cap and standard voltage regulator? Or is there a better way?

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2008-03-12 01:20
    The best way to do this is to use a rectifier and filter capacitor to get DC (probably around 16-18V) and use a switching (buck) regulator to produce +5V. There are some nice ready-to-go no-other-components-needed switching regulators from National Semiconductor and Texas Instruments.
  • Professor ChaosProfessor Chaos Posts: 36
    edited 2008-03-12 05:40
    Mike, would you happen to have representative part numbers for the regulators you mention? I have spent a while sifting through thousands of listings and my head is spinning!


    Edit: I have come across the TI PTN78000W:

    focus.ti.com/docs/prod/folders/print/ptn78000w.html

    Is that the kind of module you had in mind?

    Post Edited (Professor Chaos) : 3/12/2008 6:03:56 AM GMT
  • Mike GreenMike Green Posts: 23,101
    edited 2008-03-12 16:22
    Someone had recently suggested the National LM2825 which is a buck switching regulator with a 1A current limit and requires no external parts. I've not used it myself, but it looks like an interesting part for this sort of thing.
  • Erik FriesenErik Friesen Posts: 1,071
    edited 2008-03-15 13:53
    If you are willing to work with a surface mount product this complete dcdc may work.

    http://www.mouser.com/Search/ProductDetail.aspx?qs=oc52yH%252bc6pXbMBQXD6wg3w%3d%3d
Sign In or Register to comment.