擬似アナログ信号を用いたスペクトラム拡散によるスイッチング電源回路のEMI低減手法の提案

抄録

In this paper, EMI reduction method for switching power supply circuit by using PLL circuit as reference signal whose spectrum is spreaded, is proposed. M-sequence pseudo random signal is employed for PLL spectrum spread. Next, we extend this low bit M-sequence pseudo random signal to spectrum spread signal called “pseudo analog signal. ” The proposed pseudo analog signal can realize that the effect of the spectrum spread is wide even if the number of bit of the pseudo random circuit is small. Simulations and measurement are performed to verify the validity of the proposed method. Simulation and measurement results indicate that the proposed method have a large effect of the spectrum spread.