Fabrication of a Low Profile Planar Transformer Using a Dual PCB Approach

Inhalt:
The high frequencies in GaN- or SiC-based switching devices allow for decreased component size reducing costs, weight and space. In case of transformers, this trend lead to the development of planar designs integrating the core in the circuit board and using the copper traces as windings. While showing good performance, these designs mostly suffer from high costs or complex technologies. The presented transformer on the other hand offers an intentionally simple design based on two-layer boards. The ferrite core is made from sheet material from DMEGC that is laser cut to create a customized shape and can be stacked to reach the desired inductance in the range of five to 25 muH. The transformer shows best results in a frequency range of 100 to 800 kHz with a resulting Q-factor of over 20 and a coupling coefficient of up to 98,5%.