EMC Filter for DC/DC switching controller optimized


Modern power supplies need to reduce power loss to maintain a high degree of efficiency. Switch mode power supplies and DC/DC switching controllers are state of the art and allow great efficiency, but if the design of the circuit and circuit board layout is less than ideal this can result in increased emission of radio interference voltage. This article discusses the systematic implementation of input filters for reducing symmetric interfering voltage in DC/DC switching controllers.


An input filter is indispensable and should be considered even during the developmental phase. The differential mode interference can be suppressed at a DC/DC switching controller with an LC filter, and the interfering voltage can be reduced to an acceptable level. If the input filter is well designed and the passive filter elements are sensibly chosen, the highest possible insertion loss can be attained while maintaining the stability of the switching controller.

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