Research on periodic switching frequency modulation for conducted EMI suppressing in power converter

This paper is devoted to explore modulation techniques with deterministic profiles reducing the peak EMI in a power converter. In this paper, the effect of primary modulation parameters such as modulation profile, modulation index and modulation frequency on peak EMI suppression is numerically simulated and discussed while a fully integrated spread spectrum clock generator (SSCG) with triangular modulation is presented whose major advantages are good robustness, small size and low-power consumption. The proposed SSCG has been applied to a fly-back switching converter and the results of the experiment confirm the proposed circuit.