Analysis of switching frequency modulated synchronous buck converters

This paper is devoted to the analysis of the effect of switching frequency modulation (SFM) used for EMI reduction on the synchronous buck converters (SBC) parameters, such us output voltage ripples (OVR), peak power component currents, etc. In the paper SBC are studied analytically, using computer simulations and experimentally. The most careful attention is paid on the peak-to-peak OVR because it is the most problematic parameter due to the use of SFM. Several useful guidelines for the choice of SFM parameters and slight modification of the control circuit to get peak-to-peak OVR as small as possible are also proposed. The results presented in the paper can simplify the design of SBC with SFM.