ABSTRACT
The single-stage LC filter is usually designed with a prime consideration for low insertion loss. The inductor is usually designed for a high Q factor and the capacitor chosen with a low equivalent series resistance and high-energy density characteristics. If a negative resistance of value is connected across an input filter comprising L and C, oscillation will occur at approximately the resonant frequency of the LC filter circuit. Without going into the jargons of the orthodox network synthesis, suffice to say that the usual filter requirements for power converters are low-pass filters. For a given attenuation at a given frequency, it is possible to graphically construct the required filter response first and then calculate or estimate the required element values. The resonant frequency of the input filter should be kept at least one decade away from the resonant frequency of the output filter to avoid interaction.
