System Output Calculations

Discussion in 'General Electronics Chat' started by sgonzalez90, Feb 22, 2014.

  1. sgonzalez90

    Thread Starter New Member

    Feb 5, 2014
    8
    0
    Perhaps I'm overlooking this and thinking about this too complexly...but this is my question.

    When analyzing system designs for example a PCB layout with hundreds of components...passive and active devices....how do I calculate the total output power?

    I thought perhaps the best method would be to analyze datasheets for active devices...use the (typically) max power output, or output resistance...or voltages/currents and with just KCL/KVL sum up all values...

    Is there perhaps a reference on this? I know my power calculations...but I'm fairly new to large scale designs and would like to refine this skill.

    Thank you in advance! :D
     
  2. studiot

    AAC Fanatic!

    Nov 9, 2007
    5,005
    513
    Have you thought about power supply voltage x power supply current?
     
  3. ScottWang

    Moderator

    Aug 23, 2012
    4,855
    767
    To collecting all the datasheets of parts that you have used.
    According to the datasheets to calculating the current of each part.
    Adding all the current of parts, and plus some more current about 20%~50% for backup request, 300%~500% for the motor if the system needed.
     
  4. sgonzalez90

    Thread Starter New Member

    Feb 5, 2014
    8
    0
    So you are saying look at the max output power parameters or typical of the power supply?

    As an alternative, would it be practical to calculate the Thevenin equivalent circuit and calculate load from these parameters?

    Thanks
     
  5. studiot

    AAC Fanatic!

    Nov 9, 2007
    5,005
    513
    It would help if you were more clear about what you are trying to do.

    Gauge the power requirements of an existing board or the requirements of a design.

    In the old days up to about TTl and LSI chips there were rules one could follow, but these days there are so many different types these rules have largely been forgotten.

    It is surely simpler to build or simulate the circuit and measure?
     
  6. crutschow

    Expert

    Mar 14, 2008
    13,028
    3,237
    By "output power" to you mean the total power from the power supply consumed by all the components in the circuit? The easy way is to simulate the circuit and measure the power consumed. The old way is to calculate the power of each and every device and add them all together, which is a lot of grunt work. ;)
     
  7. sgonzalez90

    Thread Starter New Member

    Feb 5, 2014
    8
    0
    I basically have a system schematic of an old PCB with various components with no available models...so I'm basically just looking to find the total output power for the circuit under no load and then under full load.
     
  8. studiot

    AAC Fanatic!

    Nov 9, 2007
    5,005
    513
    The more information you supply the better will be the quality of the help.

    So post your schematic and any other useful info.
     
Loading...