A compact and efficient design of the input EMI filter is one of the main challenges in high-density switching regulator design and is critical to achieving the full benefits of electrification in industrial, enterprise, aerospace and other highly constrained system environments. For AC-input applications in general, CM chokes and Y-capacitors provide CM filtering, whereas the leakage inductance of the CM chokes and the X-capacitors provide DM filtering. However, CM filters for such applications may have limited Y-capacitance due to touch-current safety requirements and thus require large-sized CM chokes to achieve the requisite attenuation – ultimately resulting in filter designs with bulky, heavy and expensive passive components. Fortunately, the deployment of active filter circuits enable more compact filter solutions for next-generation power conversion systems.