This presentation was part of our virtual conference (1-3 Dec): WE meet @ Digital Days 2020
Conducted emissions filtering introduced on the input of a DC/DC regulator are common for various applications. PoE, 48V, 24V, or 28V DC rail systems are some of those.
On the face of it, this is a simple and effective LC filter solution to achieve compliance and to reduce differential mode noise at the switching frequency of the regulator and its harmonics to the required limit levels of the relevant standard.
We will investigate the pitfalls of this simple solutions and how to select the L and C and what impact they have on the stability of the power supply control loop.