Inductor winding capacitance cancellation using mutual capacitance concept for noise reduction application

In this paper, the properties of mutual capacitance between two capacitors are first discussed. It is found that the effects of mutual capacitance can be represented by two positive or negative capacitors across the two capacitors. These two equivalent capacitors can be used to cancel the parasitic capacitance of inductors. Because the mutual capacitance can be emulated using two small capacitors, the proposed method can easily be implemented in practical components. The prototypes are then built and the cancellation is verified using a network analyzer. Further EMI measurements in a practical power circuit prove that there is a significant improvement in the inductor's filtering performance.