On the cross-noise in multi-output dc-to-dc converters

In a multi-output dc-to-dc converter with the inductor coupling, the noise generated in the one of multiple loads is transmitted to the other loads. It is called “cross-noise.” This paper describes the analytical and experimental considerations on this cross-noise. The high-frequency equivalent circuits for the cross-noise in a two-output dc-to-dc converter are presented, which are composed of parasitic parameters and have several parallel and series resonances. The frequency responses against the high-frequency noise of 100KHz through 10MHz are calculated from these equivalent circuits, and agree well with the experimental results. Furthermore the cross-noise transmission characteristics of another type converter are discussed.