DC-DC buck converter

Discussion in 'The Projects Forum' started by electric77, Mar 18, 2016.

  1. electric77

    Thread Starter New Member

    Mar 18, 2016
    9
    1
    Hi
    Iam doing a project that requires to step down 36 V to three loads that need about 5V and 2A, 2A and 5 A.
    if i connect my loads in parallel, to my buck converter that has the following secifications:
    input voltage: DC 5-40V; Output voltage: DC1.2-36V; Out current: 12A(max.); Output power: 100W
    will i damage my loads

    loads are arduino or raspberry pi (5V 2A)
    ultrasonic sensor (5V 2A)
    and servo motor ( 5V 5A)

    question is, is my buck converter always producing 12 A?
    if yes then best option would be resistor to reduce current?
    and also how do i protect circuit from feedback current due to servo (any diode?)
    plz plz plz
    help
     
  2. Sensacell

    Well-Known Member

    Jun 19, 2012
    1,134
    268
    Your loads draw current- the DC to DC converter only produces current demanded by the loads.
    No no load, no current.

    No problem as long as the total load current is less than the maximum rated capacity of your DC to DC converter.

    "feedback current" is an undefined and unlikely problem.
     
    electric77 likes this.
  3. ronv

    AAC Fanatic!

    Nov 12, 2008
    3,293
    1,262
    You may need to be careful that you don't reverse the motor before it has stopped.
     
  4. electric77

    Thread Starter New Member

    Mar 18, 2016
    9
    1
    what do you mean?
    please explain
    tight on time and dont want to burn any item.
     
  5. #12

    Expert

    Nov 30, 2010
    16,355
    6,852
    "Don't reverse the motor before it has stopped" means, "Wait until the motor stops before you reverse its direction."
     
  6. #12

    Expert

    Nov 30, 2010
    16,355
    6,852
    Is you car battery always producing 450 cold cranking amps?
    No.
    Does the car battery force 450 amps through your headlights?
    No.
     
    electric77 likes this.
  7. JJacobs

    New Member

    Feb 7, 2015
    1
    0
    Basics...
    Your buck regulator regulates the Voltage to the loads. It will attempt to hold the voltage at the output to 5V regardless of the load on it. That is the function of a voltage regulator.

    The current, up to the supplies maximum, is drawn by the load.

    The current rating of the supply is simply the maximum current the load can draw before that voltage starts to drop. You should seldom if ever be at the maximum.

    According to Ohm's Law: I = E/R, since E (voltage) is fixed by the voltage regulator, I (current) varies according to R, which is what the load draws.
     
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