Recent developments in power semiconductor technology and packaging enable power-supply implementations with increased efficiency and power density. However, the improved switching performance and smaller packaging that makes these gains possible is also in part responsible for elevating CM emission signatures. The shift of next-generation power electronics toward higher densities, improved performance, reduced weight and lower cost necessitates a new approach to EMI filter design. Within this context, a compact and efficient design for the EMI filter stage is one of the key challenges in high-density switching regulator designs, particularly for automotive and industrial applications where solution size and cost are important considerations.
Practical results from an active filter implementation (detailed above) to suppress the measured CM noise signature indicate a significant volumetric reduction of the CM choke components when benchmarked against an equivalent passive-only design.
Additional benefits include reduced power loss for better thermal management
and increased system-level reliability, lower component weight for better mechanical robustness, improved high-freqeuncy performance due to lower choke parasitic capacitance, and reduced costs.