Coreless printed circuit board (PCB) transformers with high power density and high efficiency

The authors report the use of a coreless printed circuit board transformer for power conversion with very high power density and efficiency. A coreles s PCB transformer with an outermost radius of similar to 1 cm and 19 turns for both the primary and secondary windings can transfer 19W at an efficien cy of 90%, resulting in a record power density of 24 W/cm2. The power densi ty and energy efficiency of a coreless PCB transformer are higher than thos e of core-based microtransformers. Coreless transformers are simpler in str ucture, easier to implement in silicon wafer and cheaper than core-based pl anar transformers.