Effects of diode recovery characteristics on electromagnetic noise in PFCs

This paper presents a comparison of different diodes used in boost power factor correctors (PFC) from the point of view of electromagnetic compatibility. Diodes produced by various manufacturers, all with the same nominal recovery time, have been characterized and tested on a PFC circuit. Whereas the conducted emissions do not depend on the used diode, the radiated emissions are strongly influenced by the recovery behavior. In particular the snap factor is important for the noise level and the reverse capacitance determines the ringing frequency and hence the noise peak.