PCB-Based Magnetics Integration and Common-Mode Noise Suppression for A High-Frequency PFC

Abstract

Magnetics with embedded windings in printed circuit board (PCB) reduces labors in power-supply manufacturing and enables implementation of advanced electromagnetic interference (EMI) suppression techniques. However, planar inductors with embedded PCB windings could potentially suffer higher winding loss due to the accumulation of magnetomotive force (MMF) and the skin effect, compared to conventional litz wire-based designs. One approach to reduce winding loss is to interleave windings of different phases in a form of coupled inductor. In this way, however, the available coupling coefficient is usually constrained to a certain high level that limited by the specific winding structure. This paper proposes a winding interleaving approach that extends the lower limit of coupling coefficient to zero while still maintaining the benefits of winding interleaving. Furthermore, balance technique is integrated with PCB winding-based inductors for common-mode (CM) noise suppression. A 2.2 kW GaN-device based totem-pole power-factor correction (PFC) converter is demonstrated as an example. The proposed PCB-based inductor structure enables a peak efficiency of 99% and a <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$20 \ \mathbf{dB}\mu\mathrm{V}$</tex> CM noise suppression in experiment.