DC supply in parallel

Discussion in 'The Projects Forum' started by bibek86, Apr 11, 2014.

  1. bibek86

    Thread Starter New Member

    Apr 11, 2014
    2
    0
    Hi,

    I am confused about this connection and I would like some suggestions. I need a +5V Gnd -5V supply for my circuit. The current required is around 4A. I have two benchtop supplies, same model, rated at 3A. Each one has two outputs. So I can use series tracking mode in the power supply to get +5V Gnd -5V.

    Now I was wondering how to fulfill the current requirement for my circuit.
    I have thought of two ways:

    1. Run each power supply in series tracking mode then connect the +ve -ve and ground terminals using wires for parallel connection of two power supplies.

    2. Run each power supply in parallel tracking mode to increase the current output, and then connect +ve terminal of one supply to -ve terminal of another supply to make series connection between two supplies.

    Please suggest which if any of these two methods is better.
     
  2. ScottWang

    Moderator

    Aug 23, 2012
    4,853
    767
    Your circuit need +5V, Gnd, -5V, and need 4A current, then they should be +5,GND need 4A, and GND ,-5V need 4A, but your current only can offer 3A, so the current of power supply is not enough.
     
  3. MrChips

    Moderator

    Oct 2, 2009
    12,435
    3,360
    I assume all four 5V@3A supplies are independent and floating.
    I cannot see any preference on your two choices.
    I would try the series arrangement.
     
  4. bibek86

    Thread Starter New Member

    Apr 11, 2014
    2
    0
    Sorry I did not explain properly. Each of the bench top supply has dual output. So the two outputs from one benchtop can supply 3A each.
     
  5. ScottWang

    Moderator

    Aug 23, 2012
    4,853
    767
    So two output each offer 3A, some psu can be in parallel directly, but some don't, maybe you can in series a 0.2Ω/5W for each output and then in parallel two 0.2Ω/5W, the common pin will be the new output.
     
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