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July 2012 Doc ID 022603 Rev 1 1/40
AN4026
Application note
19 V - 90 W adapter with PFC for laptop computers
using the L6563H and L6699
Introduction
This application note describes the performance of a 90 W, wide-range mains, power-factor
corrected, AC-DC adapter demonstration board. Its electrical specifications are tailored to 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 L6699 resonant controller. Thanks to the chipset used, the main features of this
design are very high efficiency, compliant with ENERGY STAR
®
eligibility criteria (EPA rev.
2.0 EPS) and very good efficiency also at light load, and compliance to the new ErP Lot 6
Tier2 requirements. No load input power consumption is very low too, well within the
international regulation limits.
The controller of the LLC stage is the L6699, integrating innovative functions such as self-
adjusting adaptive deadtime, anti-capacitive mode protection and proprietary “safe-start”
procedure preventing hard switching at startup.
Figure 1. EVL6699-90WADP: 90 W adapter demonstration board
www.st.com
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