Cross Noise in Multi-Output DC-to-DC Converters

In a multi-output dc-to-dc converter with cross regulation, the noise generated in one of the multiple loads is transmitted to the other loads. It is called ?cross noise.? This cross noise is analyzed and experimental results are given. High-frequency equivalent circuits, which are composed of parasitic parameters and have several parallel and series resonances, are presented for cross noise in a two-output dc-to-dc converter. The frequency responses versus 100 kHz through 10 MHz noise are calculated from these equivalent circuits and agree well with experimental results.     

Noise Generation of a Switching Regulator

Analytical and experimental considerations on the surge and noise generated in a typical switching regulator are discussed. There are two kinds of surges which occur in the switching instants of the transistor. These surges appear as high voltages across the semiconductor elements and decrease their reliabilities. Corresponding to the surge generation, noise voltages appear in the output terminals and may induce malfunctions of a signal processing device connected to the regulator. We analyze these surge and noise voltages by means of high-frequency equivalent circuits.