EMC Analysis of the Inverting Boost/Buck Converter Topology

This paper describes the electromagnetic compatibility (EMC) analysis of an inverting buck/boost converter. The inverting buck/boost converter differs from other DC/DC converters, such as the noninverting boost or buck converters, in that one inductor terminal is connected to the ground and not to the input or output of the converter, i.e., neither input nor output is isolated from an EMC perspective. A SPICE model was developed for analyzing the EMC properties of the circuit. Two electromagnetic interference EMI-relevant resonances were observed depending on the state of the switch. Simulations are confirmed with measurements using a circuit designed from discrete components. Further, integrated commercially available converters were analyzed and showed EMC properties that were similar to those of the general model.