An Optimal Minimum-Component DC-DC Converter Input Filter Design and Its Stability Analysis

Very high switching frequency (1 MHz or more) is highly desired for dc-dc converters to achieve high power density. State-of-the-art dc-dc converters are capable of achieving high-efficiency with the high-switching frequency, which promotes an opportunity and challenge for a redesign of the traditional input filters. This paper describes an optimal input filter design with minimum components count, which consists of fewer passive components than common input filter topologies. The proposed methodology leverages parasitic parameters of both converter and filter elements in order to achieve optimal performance. It also features high flexibility without sacrificing performance. The stability analysis has been performed to ensure a stable system. A prototype has been realized for a transformer-coupled zero voltage switching buck-boost converter and performance has been successfully validated against design targets.