Measured performance of a high-power-density microfabricated transformer in a DC-DC converter

Experimental measurements are reported on microfabricated power conversion transformers. A device fabricated using a simplified 'sandwich' process confirms predicted performance in an 8 MHz DC-DC power converter, where it achieves a power-handling density of 22.4 W/cm/sup 2/ at 61% efficiency. Preliminary test results are reported for transformers based on a closed-core design, which is expected to achieve higher efficiency.