An experimental study of EMI reduction of DC-DC converter with frequency hopping technique

In this paper, the EMI problem of the DC-DC converter is discussed. The power spectrums of the DC-DC converter's nodes are analyzed and the noise scanner method is used to prove that the switching node of the DC-DC converter is the dominant source of EMI. To reduce EMI of DC-DC converters, frequency hopping technique can be applied. The DC-DC converter with frequency hopping technique is fabricated using 180nm CMOS process. The test chip results by IC-stripline and noise scanner methods show a significant improvement in EMI. The EMI reduction amount is 6.87 dB at fundamental switching frequency by applying the frequency hopping technique with IC-stripline measurement.