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Switch-mode voltage regulators — Parallax Forums

Switch-mode voltage regulators

Jay KickliterJay Kickliter Posts: 446
edited 2009-03-01 14:48 in General Discussion
What do you guys use for switch-mode voltage regulators? All I can find are these:

http://www.dimensionengineering.com/DE-SW033.htm

Do they work? I imagine that making your own wouldn't bee too difficult. It says that with an additional capacitor on the output it is possible to run ripple-sensitive ICs.

Comments

  • PJAllenPJAllen Banned Posts: 5,065
    edited 2009-02-27 20:56
    Making your own not difficult you imagine?

    Investigate: Texas Inst. PT5100 series and Datel 78SR series
  • stamptrolstamptrol Posts: 1,731
    edited 2009-02-28 00:35
    I use the Texas Instruments PT5100 series. Easy to use, very rugged, one external capacitor.

    Cheers,

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    Tom Sisk

    http://www.siskconsult.com
    ·
  • SRLMSRLM Posts: 5,045
    edited 2009-02-28 01:40
    I use these. I looked at the datasheet, and it didn't mention anything about switching or not, but I seem to remember somewhere where it does say switching.
  • PJAllenPJAllen Banned Posts: 5,065
    edited 2009-02-28 03:31
    Sorry, LD1085s·are linear devices.
  • Mike2545Mike2545 Posts: 433
    edited 2009-03-01 02:40
    Hi, I was reading your thread and saw PJ Allen talk about the 78SR switching voltage regulators. I couldn't help myself and bought one from Mouser to play with. Pricey compared to the plain-Jane variety. I'll have to let you know what I think.

    Thanks for the ideas.

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    Mike2545

    This message sent to you on 100% recycled electrons.
  • PJAllenPJAllen Banned Posts: 5,065
    edited 2009-03-01 04:23
    Who's Plain Jane?

    Anyway, the 78SRs are great devices, keep 'em under 1/2A and you're golden, old chap.

    And they cost about 1/3 less than the PT5100s.
  • Mike2545Mike2545 Posts: 433
    edited 2009-03-01 05:08
    Old Chap?...

    Yea, plain Jane 7805 voltage regulator, you know, 5 bucks a gross.

    Anyway, other than almost no heat produced what other advantages does a switching power supply/regulator have over a traditional one?

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    Mike2545

    This message sent to you on 100% recycled electrons.
  • PhilldapillPhilldapill Posts: 1,283
    edited 2009-03-01 06:06
    Efficiency is the main one. If power is an issue, then Switchers are the way to go. They have a small inductor in them, and use it kind of like a transformer. Instead of shunting the extra voltage, they literally turn the voltage and current into another value. Magic really(or at least electromagnetics in general are).

    One of the draw backs, is that a switcher does add a little noise to the supply, but this can almost always be negated by adequate bypassing capacitors. Usually isn't a problem except for extremely sensitve devices.
  • ZootZoot Posts: 2,227
    edited 2009-03-01 14:48
    I use switching regs. in all my larger projects --- you can get way more amps out of a small package, no heat, very efficient (read: easy on batteries) *especially* when running lots of 5v electronics from say, a 12v battery.

    I usually use the pre-assembled reg. boards linked to below --- 2A continuous, and they have the same pinout as 7805, 2940, etc, and about the same footprint as a 7805 with a heatsink. Assembled, tested, ready-to-go. (I know some may think these pricey, but sometimes it's nice to just have the unit ready to drop in).

    search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=PT78HT205V-ND

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    When the going gets weird, the weird turn pro. -- HST

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