This application note describes the performance of a 90 W, wide-range mains, power-factor-corrected, AC-DC adapter demonstration board. Its electrical specification is tailored on a typical hi-end portable computer power adapter. The architecture is based on a two-stage approach; a front-end PFC pre-regulator based on the L6563H TM PFC controller and a downstream LLC resonant half-bridge converter using the new L6599A resonant controller. Thanks to the chipset used, the main aspects of this design are very high efficiency, compliance with ENERGY STAR® Eligibility Criteria (EPA rev. 2.0 EPS), and very low input consumption at no-load (<0.3 W).