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ferrite core transformer

Discussion in 'Electronic Design' started by mukesh, May 16, 2007.

  1. mukesh

    mukesh Guest

    hi sir,

    i am working in the UPS field .. i wanted to know that what is the max
    freq we can choose for flyback converter ..... i am using the ferrite
    core transformer . is there any limitation for freq ? what is the
    max working freq for ferrite core transformer??????????
     
  2. MooseFET

    MooseFET Guest


    It depends on the material the core is made from and how much losses
    you can stand. Frequencies over 10MHz are often sent through ferrite
    materials.

    What material eg: 3F3 is the core made from.
     
  3. Eeyore

    Eeyore Guest

    It depends a lot on the specific material.

    There are few sinmple quick answers when it comes to ferrites !

    I would suggest though that you download a copy of Epcos's Ferrite Magnetic
    Designer application.

    Graham
     
  4. default

    default Guest

    Working in the UPS field? I rather doubt it.

    The manufacturers have very specific data on each core material and
    what frequency it covers, permeability, hysteresis curves, temperature
    range, etc..

    Ferrite is a generic description and covers a wide range of materials
    from something suitable for low pass power line filters to
    coupling/mixing into the microwave ranges.
     
  5. Eeyore

    Eeyore Guest

    Given his name I looked at his headers to see if he was posting from India 9 (would
    explain a lot) But *he's posting from an APC address* !!!!

    Maybe he ought to go ask his colleagues / cow-orkers for a hint ?

    Graham
     
  6. Tim Wescott

    Tim Wescott Guest

    Look in the catalogs. You can get ferrite cores for much higher
    frequencies than the ones you're using. The usual limitations on power
    supply efficiency vs. frequency is parasitic capacitance and diode lag
    effects, which don't come from the core. This capacitance makes it
    harder to drive the FETs quickly, and the recovery times of the diodes
    (should you use them) causes some lost energy each cycle. Dealing with
    gate capacitance increases circuit complexity, as does eliminating the
    diodes by using synchronous rectification.

    Driving the frequency up is attractive because the core size goes up
    roughly with the amount of energy it has to store, and the amount of
    energy stored is roughly proportional to the power supply's power output
    times one cycle time. This means that a higher switching frequency
    means smaller cores.

    --

    Tim Wescott
    Wescott Design Services
    http://www.wescottdesign.com

    Posting from Google? See http://cfaj.freeshell.org/google/

    Do you need to implement control loops in software?
    "Applied Control Theory for Embedded Systems" gives you just what it says.
    See details at http://www.wescottdesign.com/actfes/actfes.html
     
  7. Given his name I looked at his headers to see if he was posting from India 9 (would
    Cut the intern some slack ;-)
     
  8. Robert Baer

    Robert Baer Guest

    Max "frequency" is very dependent on the core material, as the loss
    of the core varies widly on type and material.
    Next is the current and how the winding is done (litz, multifilar,
    strip, etc).
    And last, is how fast one can switch the current (actual turn on and
    turn ooff times.
    If one gets "fast" enough, then one should think RF "linear"
    circuits; say class "C" driven ferrite transformers, where one tends to
    see sine waves for drive and output, with complex conjugate drive at the
    FET gates.
     
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