A simple question about buck converter

Discussion in 'General Electronics Chat' started by theasus, Jul 28, 2010.

  1. theasus

    Thread Starter New Member

    Sep 12, 2009
    I couldn't understand one point about this buck converter shown below.
    SW1 is closed.
    L1 delivers current to the load and then SW1 is open;
    But shown circuit above,Inductor's voltage direction is reversed.Why???
  2. Jony130

    AAC Fanatic!

    Feb 17, 2009
    sage.radachowsky likes this.
  3. Norfindel

    Senior Member

    Mar 6, 2008
    Because it's supplying current instead of absorbing it now. In that moment, the inductor is your power supply.

    The inductor tries to keep current flowing thru it constant. To do that, it must supply current, and is basically a power supply for some time.

    Compare the voltage markings of the power supply in the first image with that of the inductor in the second image.
    sage.radachowsky likes this.