The power problem of LM2575S-5.0 and MCU.

Discussion in 'Embedded Systems and Microcontrollers' started by Beanx10, Jul 20, 2015.

  1. Beanx10

    Thread Starter New Member

    Jul 20, 2015
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    This is a very nice and useful topic....So I have a question about this scenario: I have a circuit with MCU that most of the time is waiting and it consumes 10-12ma in this "waiting state"...so it powers up a couple of relays and a radio transceiver and the current consuption is about 180ma. Basically this are the two current cosuptuion it oscillates 10ma - 200ma let's say.
    In the case of the LM2575S-5.0 when you look at the datasheet it says the load current should be 20<Iload<500ma (for the 500ma configuration)...and when you look at the grapich tables...the efficiency at that low current is very low.....so the cuestion is...what is the best design for that range of consumption in terms of efficiency, ripple, cost, etc....how the value of the capacitors, inductor affects or improve the system at that range of load?....is this this the best choice for this kind of power supply? (Vin=40Vmax, 8Vmin / Iload=10ma - 200ma / Vout=5V fixed)
    .thanks in advance

    Mods Edit :
    This thread was split from 24VAC to 5VDC, now you have your own.
     
  2. ScottWang

    Moderator

    Aug 23, 2012
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    Please attach the schematic is more easier to discuss.
     
  3. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    7,387
    1,605
    A simple linear regulator will always have the lowest cost and ripple, and typically the worst efficiency.

    A switching regulator will be more complex, have the highest cost and ripple, and typically the best efficiency.
     
  4. nerdegutta

    Moderator

    Dec 15, 2009
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