AN4172 Datasheet, PDF (1/16 Pages) STMicroelectronics – IEEE802.3af class 3 PoE converter reference design

AN4172
Application note
IEEE802.3af class 3 PoE converter reference design
high efficiency flyback converter based on the PM8800A
By Antonio Rotta
Introduction
The PM8800A is a highly integrated device embedding an IEEE802.3af compliant powered
device (PD) interface together with a PWM controller and support for auxiliary sources.
This document focuses on a reference design for a high efficiency, class 3 PD (up to 13 W
input) power converter based on a flyback topology with pulse transformer driven
synchronous rectification using the PM8800A as the main controller.
Schematics of the PoE converter are given in Section 2, while the related bill of material is
detailed in Section 3. In Section 4 efficiency measurements together with main waveforms
of the PoE interface and power converter are shown.
October 2012
Doc ID 023723 Rev 1
1/16
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