A low-profile low-power converter with coreless PCB isolation transformer

Very small manually wound transformers for sub-watt de-de converters are no torious for their relatively high cost and low reliability, In this paper, an isolated low-profile low-power 8 MHz soft-switching power converter usin g a coreless printed circuit board (PCB) transformer is described. Coreless PCB transformers eliminate several problems of their core-based counterpar ts in low-power applications. The diameter of the coreless PCB transformer is merely 0.46 cm, The converter's power output is about 0.5W with a typica l transformer efficiency of 63%, The high-frequency capability, high reliab ility and the low-profile structure make coreless PCB transformers a viable and attractive option for reliable mega-hertz switching converters and mic ro-circuits.