2 offline smps switches

Discussion in 'General Electronics Chat' started by pradeeba, Mar 7, 2008.

  1. pradeeba

    Thread Starter Active Member

    Feb 27, 2008
    104
    0
    Hi,
    am planning to use two SMPS switcher IC's. input voltage will be derived from the same point. that is a am going to use fuse,bridge rectifier, input bulk capacitor as common.will ther be any problem in the circuit?
     
  2. n9352527

    AAC Fanatic!

    Oct 14, 2005
    1,198
    4
    Why do you need two?
     
  3. pradeeba

    Thread Starter Active Member

    Feb 27, 2008
    104
    0
    Because i dont want the noise to be coupled to the other section.
     
  4. S_lannan

    Active Member

    Jun 20, 2007
    247
    2
    2 controllers is a waste of time in reality.

    The majority of the noise is going to be the actual switching of the transistors of mosfets.

    Another problem is you will no longer have a isolated supply which is very dangerous :)
     
  5. scubasteve_911

    Senior Member

    Dec 27, 2007
    1,202
    1
    You will probably end up bringing more noise into your system with two, especially if they are running out of sync.

    If you want low noise, then use a linear regulator with a carefully matched transformer/rectifier section. If you have a large range of input voltages you wish to accommodate, then use a switching pre-regulator and post-linearily regulate it.

    Steve
     
  6. pradeeba

    Thread Starter Active Member

    Feb 27, 2008
    104
    0
    i have six outputs. in that two have isolated ground. the problem is the size of the bobbin will be big. for this reason i have to use 2 smps switches
     
  7. scubasteve_911

    Senior Member

    Dec 27, 2007
    1,202
    1
    Then make sure that switching is synchronized, otherwise you will have more noise than necessary.

    Steve
     
  8. pradeeba

    Thread Starter Active Member

    Feb 27, 2008
    104
    0
    Apart from noise, will there be any problem in operation?
     
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