EMI reduction by analog noise spread spectrum in new ripple controlled converter

This paper proposes a new ripple controlled switching converter and a new spread spectrum technique for EMI reduction. The new ripple controlled converter includes a Hip-Hop after the output of the comparator. The new spread spectrum technique uses a PLL circuit modulated by pseudo analog noise. The PLL circuit modulates a reference clock with non-periodic analog noise. This modulated clock is provided to a flip-flop trigger in order to generate the switching pulses, and the spectrum of the switching pulse is widely spread; our simulation results show that the peak levels of the spectrums of the fundamental and the harmonic frequencies can be significantly reduced.