It depends on the switching frequency, and not all SMPS run at a high enough frequency to justify ferrite. On top of that ferrite is effectively just iron in a ceramic.
The gap is controlled by the cross section of the core but also contributes to EMI. The sizing concerns are typically related to the latter problem.
An SMPS can easily use an external feedback circuit and may do so for certain types of applications. For mass manufactured low current applications you can often buy them with one integrated.
The gap is controlled by the cross section of the core but also contributes to EMI. The sizing concerns are typically related to the latter problem.
An SMPS can easily use an external feedback circuit and may do so for certain types of applications. For mass manufactured low current applications you can often buy them with one integrated.