Investigation of Parasitic Capacitance Models for Planar Transformers: Accuracy and Impedance Prediction

Planar transformers, with low-profile magnetic cores and PCB windings, excel in high-frequency and high-efficiency applications. However, high parasitic capacitance poses challenges, resulting in current/voltage distortions and common mode noises. Accurate modeling is vital, and different models have been proposed. Nonetheless, comprehensive verification of impedance prediction across various scenarios is lacking. This study presents calculation methods, evaluates model accuracy and capabilities, and examines different transformer structures and scenarios. Four transformers are constructed to validate calculations and assess model performance.