Connect with us

Parallel Connecting Two Identical Switching PSUs

Discussion in 'Electronic Design' started by Holophote, Mar 25, 2007.

Scroll to continue with content
  1. Holophote

    Holophote Guest

    If electronics has been your hobbly or
    profession for many years, I'm sure you've
    connected two identical linear regulators.
    An example would be connecting two 5 amp
    LM338 regulators to produce a 10 amp supply.

    I've never done this with identical switchmode
    regulators, and I'm wondering if it's practical
    or even possible?

    I've got two 20 volt - 3 amp brick style (also
    called table-top) switching power supplies.
    I'd like to combine the ouputs. In effect,
    you would end up with an 20 volt - 6 amp

    They are manufactured by Pihong.
    Model No. PSA60W-200.
  2. Genome

    Genome Guest

    No no no, it's not a very auspicious start.

    We just don't do that sort of stuff.

    I've already reported you to but (un)fortunately
    they won't pay attention.

    Stop being obsequious.

    Obviously you need N-1 diode redundancy and a PID contoller.

    The PIC men will be along later to sort you out.

  3. Eeyore

    Eeyore Guest

    No, it's bad practice.

  4. Lionel

    Lionel Guest

    Hell no! The two regulators will 'fight' over the exact output
    It's dangerous & it won't work.
  5. Phil Allison

    Phil Allison Guest


    ** Shame how it is so easy to do.

    Natsemi publish application schems for it.

    ........ Phil
  6. Lionel

    Lionel Guest

    All of which involve additional circuitry for load balancing that
    reduces regulation quality.
  7. Joerg

    Joerg Guest

    I wouldn't do that. Amongst lots of other pathologies that can happen,
    just imagine if one comes up a few millisecond later than the other and
    feeds it from the back? KABLOUIE...
  8. Phil Allison

    Phil Allison Guest

    "Phil Allison"

    ** Ohhh - just a moment ago you said it couldn't be done at all.

    Things are looking up.

    It is in fact very easy to parallel two LM338s without loss of performance.

    YOU just do not know how.

    ........ Phil
  9. Lionel

    Lionel Guest

    Subject: "Parallel Connecting Two Identical Switching PSUs" - which
    can't be done without a strong risk of letting out the magic smoke.
    No problem, I'm keen to learn. So, how do you do it without additional
    components, & without reducing regulation quality?
  10. Phil Allison

    Phil Allison Guest

    "Lionel the LIAR "

    ** Lionel - YOU are a DAMN LIAR !!

    ** YOU do not get to set such conditions on how.


    ........ Phil
  11. Lionel

    Lionel Guest

    Go ahead, parallel up the outputs of two switching PSUs & prove me
    wrong. Please post photos of them afterwards. ;^)
    I knew you couldn't do it. Thanks for proving me correct.
    Aw. Diddums.
  12. Phil Allison

    Phil Allison Guest

    "Lionel the CRIMINAL LIAR "



    .......... Phil
  13. Lionel

    Lionel Guest

    Translation from Philthish to English: "Oh shit, he's got me there.
    I'd better scream & yell so nobody notices! That ALWAYS works!"
    Translation from Philthish to English: "Oh shit, how can I scare him
  14. No. I can remember when 3-terminal regulators were the latest
    thing, but I've never run them in parallel. If you need that much
    current, either you use a higher current regulator, or add an external
    pass transistor.

    What you're missing is that 3-terminal regulators were originally called
    "on-card regulators". The intent was that you'd have one raw voltage
    source, and distribute it to the various boards. ON each board, you'd
    regulate with one of those 3-terminal regulators. That provided a level
    of isolation between the boards, and meant you didn't need some massive
    regulator and heat sink to feed it all.

    If you really need more current than one switching supply supplies, then
    don't be cheap, and buy a higher current switching supply. Or rework the
    circuit so you can use two power supplies to feed separate parts of the

    Or rethink things, because you may not need a regulated supply, since
    a lot of real current hogs don't need regulation.

    Don't pass off hobbyist stuff as a design issue.

  15. Phil Allison

    Phil Allison Guest

    "Lionel" <>

    ** This pile of sub human garbage is another psychotic TROLL

    Narcissistic and malicious as they come.

    ......... Phil
  16. Phil Allison

    Phil Allison Guest

    "Michael Black"
    ** Wrong - again.

    ** Must be a lotta things YOU have not done - dickhead.

    ** The latter means losing the overcurrent and overtemp protection built
    into such regulators.

    Also, two parallel regulators have double the dissipation capacity of one -
    a higher current type will usually not.

    Plus there is the cost issue - higher current regs are more expensive
    than two in parallel.

    ......... Phil
  17. Lionel

    Lionel Guest

    Phil "Philthy" Allison's histrionic Usenet history:
    "Results 1 - 10 of about 2,320 for (**** OR
    troll OR wanker)"

    Poor old Phil has a bit of a temper. ;^)
  18. Phil Allison

    Phil Allison Guest

    "Lionel" <>

    ** This pile of sub human garbage is another psychotic TROLL

    Narcissistic and malicious as they come.

    Anther usenet CRIMINAL.

    ......... Phil
  19. Why don't you plonk the phil thing? Everyone else has.
  20. Phil Allison

    Phil Allison Guest

    "Homer J Simpson"

    ** YOU are disgusting and pathetic MORON - " Simpson".

    Lionel is an obvious crazy person and a blatant TROLL.

    Is your reading comprehension so INEPT you cannot tell ?

    ........ Phil
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day