Flyback Micro-Converter Design with an Integrated Octagonal Micro-Transformer for DC-DC Conversion

The work presented in this paper concerns the design of an integrated flyback DC-DC micro-converter operating at high frequencies. The flyback converter consists of only one transformer. The integrated micro-transformer in the flyback micro-converter is composed of two planar stacked coils with spiral octagonal geometry. Basing on Mohan’s method, the geometrical parameters are evaluated. The different parasitic effects created in the stacked layers are grouped perfectly in the equivalent electrical circuit that summarizes all parasitic effects. The integrated micro-transformer is characterized by scattering parameters extraction. The thermal and electromagnetic effects generated in the micro-transformer are illustrated, using finite elements method on COMSOL Multiphysics 5.3 software. To validate the electrical model, the simulation of the flyback micro-converter containing the equivalent electrical circuit of the micro-transformer is established, using PSIM 9.0 software. The gap between the coils is considered as an integrated MIM capacitor created at high frequencies leads to create a low pass micro-filter with the secondary coil.