Nowadays, switching power dc/dc converters (SPC) are crucial in many electronic devices, especially for portable electronics, such as laptops, mobile phones, etc. The advantages of the use of SPC are rather well known -high power efficiency and high volumetric characteristics. Electromagnetic interference (EMI) is considered as a major problem of SPC, firstly, because of conducted EMI that can disturb operation of other devices connected to the same line, secondly, because of radiated EMI that can significantly affect performance of other electronic devices placed nearby [1]. The classical ways to reduce EMI often include the use of input and output filters, shielding, etc [1, 2]. EMI can also be reduced by modulating the switching frequency in random, chaotic or periodic manner [1]. As a result of the switching frequency modulation (SFM), energy of discrete harmonics of unmodulated switching frequency is spread over a wider frequency range, thus peak EMI levels are significantly reduced [2] as it is shown in Fig. 1.
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