Design of local minimization in the noise spectrum of randomly switched DC/DC converters

The problem of controlling the power spectral density (PSD) of random modulation techniques has attracted considerable interest recently in power electronics field. In this paper we analyze the PSD of DC/DC converter that uses randomized switching frequency pulse width modulation with constant duty cycle. We give a novel understanding for the peaks visible in the PSD. Based on the analysis we derive a reasonable means to null at a point or suppress the PSD over a band of specified frequencies. We also present the analysis of the limitation imposed by practical constraints on the range and mean of the switching frequencies. Simulation results verify our approach.