What's the difference of isolated dc dc converter and non-isolated dc dc converter?

Discussion in 'Power Electronics' started by huang, Jul 20, 2016.

  1. huang

    Thread Starter New Member

    Jan 8, 2014
    10
    0
    Hey guys, I am looking for this questions ,who could answer compeletely.
    What's the difference of isolated dc dc converter and non-isolated dc dc converter?
    Many thanks
     
  2. AlbertHall

    Well-Known Member

    Jun 4, 2014
    1,951
    387
    An isolated DC-DC converter uses a transformer between the input and output so there is no connection between the input and the output.
    If it is not isolated then, generally, one of the input supply pins is connected is connected to one of the output pins.
     
  3. huang

    Thread Starter New Member

    Jan 8, 2014
    10
    0
    Thanks very much for your answer.
     
  4. kittoo

    New Member

    Jul 11, 2016
    25
    1
    isolated DC-DC converter uses a transformer between the input and output circuit ,main disadvantage of isolated dc-dc converter is circuit becomes bulky & transformer losses will also add that will decrease the efficiency.
     
  5. Techno Tronix

    Member

    Jan 10, 2015
    140
    10
    Isolated dc dc converters provide no electric contact between input and output circuits which may be a requirement by certain safety agencies where non-isolated does not provide dielectric isolation between input and output circuit.
     
  6. crutschow

    Expert

    Mar 14, 2008
    13,018
    3,235
    I worked on a spacecraft power system and all the circuit power had to be isolated from the spacecraft supply power (the batteries and solar panel) since they didn't want any spacecraft ground current flowing through the circuit grounds, so all the converters were isolated with transformers in the switching circuit.
     
  7. AnalogKid

    Distinguished Member

    Aug 1, 2013
    4,542
    1,251
    Most medium to large industrial modular switching power supplies (500 W - 2 kW) make 360 Vdc-ish in a front end boost PFC, distribute this DC to the modules, and each module has a switching DC/DC converter. One company creates switched high power high voltage in the front end and distributes that to the modules, where the first thing in the door is the transformer primary. Only one power switching stage, more efficient, more reliable.

    ak
     
  8. JMac3108

    Active Member

    Aug 16, 2010
    349
    66
    The question was well answered. I would just add that the isolation is not just in the power path of the power supply (transformer), but also in any feedback that goes from the secondary side to the primary. Feedback isolation is often done with an opto-coupler.
     
  9. Dr.killjoy

    Well-Known Member

    Apr 28, 2013
    1,190
    156
    How much do you really lose in 1:1 transformer??
     
  10. kittoo

    New Member

    Jul 11, 2016
    25
    1
    Lose will be less but based on the circuit you will select transformer, whether it will be centre tap transformer or 1:1 transformer. Mostly we won't use 1:1 transformer.
     
  11. #12

    Expert

    Nov 30, 2010
    16,302
    6,812
    It depends on the quality of the transformer. I would guess, at the most, less than 10% of the transferred power. Some transformers are much better than that.
     
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