Silicone-Iron Oxide Nanocomposite Encapsulants for Common Mode Noise Reduction in Switching Power Electronics*

The use of polymer encapsulants continues to permeate the electronics industry as a way to improve the reliability of packaging solutions, and the incorporation of nanomaterials presents an area of potential advancement. Management of electromagnetic noise represents a design challenge in power electronics that can be aided through the use of nanoparticle-enhanced encapsulants. Aluminum heat sinks often create common mode noise from AC disturbances generated by switching power supplies. Mitigation of this noise in modern electronics results in large increases in device efficiency; nanoparticles which have an intrinsic susceptibility to electromagnetic fields could add another dimension to encapsulant functionality by improving noise shielding. In the study presented herein, iron oxide nanoparticles were incorporated into a silicone rubber matrix to create an electomagnetically-susceptible nanocomposite in an effort to reduce common mode noise. After applying the nanocomposites to a prototype heat sink, a noticeable reduction in common mode noise was observed with just a relatively small amount of nanomaterial. Introducing this simple concept to modern designs will aid in improving noise management in power electronics devices.