Will my psu overload?

Discussion in 'General Electronics Chat' started by vonsworld, Nov 3, 2014.

  1. vonsworld

    Thread Starter Member

    Apr 27, 2011
    Please excuse this simple question, since I am a newbie...

    If you have a regulated switching PSU which for example produces 5 amps at 15v, what happens if your application tries to draw more than 5 amps?

    Does the regulator IC simply refuse to supply any further current, or does it overload and for want of a better phrase, go bang?

    I understand that when building a regulator IC circuit you can limit the output voltage and current by adjusting the resistance to some of the IC pins, does this mean the IC will refuse to supply current over the set limit without being damaged?

    Thanks for your help :)
  2. MrChips


    Oct 2, 2009
    It depends on the design of the PSU. Most designers designing a 15V@5A supply will add a bit of overhead. So the supply will not suddenly stop working.
    Typically what could happen is the voltage will start to fall below the rated voltage. Components will start to get hotter than their design specifications.
    If you draw way over the rated 5A, you could trigger the short circuit protection and the supply will shut down or blow a fuse.
  3. ronv

    AAC Fanatic!

    Nov 12, 2008
    Some are protected from over load. Others will kill themselves try to provide the current. :eek:
  4. Dr.killjoy

    Well-Known Member

    Apr 28, 2013
    A home built power supply or store bought power supply...
  5. ISB123

    Well-Known Member

    May 21, 2014
    Voltage drops to very low value and regulator gets very hot in short time so you better have fast hand to flick the off switch.