12A 1.8V Buck Converter - Compensation Network

Discussion in 'General Electronics Chat' started by ozsm001, Mar 15, 2016.

  1. ozsm001

    Thread Starter New Member

    Mar 15, 2016
    Hi Experts!

    Just have a question regarding the below circuit. Could someone tell me the role that C449 plays in the below buck converter circuit and how this part can effect the output of the circuit?? We have a situation where this part has been swapped with an unknown part (looks like a fuse, Inductor or a resistor) in place of a 27nF capacitor. We would like to know what impact this would have on the circuit? Any help you can provide would be very much appreciated! The IC in question is L6728AH.

    C449 appears to be part of the Compensation network but it is unclear to us how this could impact Vout if it is replaced with an "unknown" part such as a resistor, fuse or inductor. Would it be possible for this part to impact V-out in such a way that V-out would become unstable?

    Buck Converter.PNG

    Compensation Network.PNG
  2. ronv

    AAC Fanatic!

    Nov 12, 2008
    Yes, it is for stability. It gives more gain and phase to high frequencies than low. So if Vout is changing quickly (say from a load change) the regulator will have good response.