UM1063 Datasheet, PDF (1/32 Pages) STMicroelectronics – The PM8803 is a highly integrated device embedding

UM1063
User manual
EVALPM8803-FLY: IEEE802.3at compliant demonstration kit with
synchronous flyback converter
By Antonio Rotta
Introduction
The PM8803 is a highly integrated device embedding an IEEE802.3at-2009 compliant
powered device (PD) interface together with a PWM controller and support for auxiliary
sources. Figure 1 is an image of the EVALPM8803-FLY PoE+ demonstration board. The
same PCB can be populated with different components to support various configurations
and topologies (synchronous flyback with or without active clamp, flyback with diode
rectification).
This document focuses on a reference design for PoE+ based on flyback topology with
synchronous rectification, with the PM8803 as the main controller.
The schematics and board layout of the PoE+ converter are given in Section 2 and 3 while
the related bill of material is detailed in Section 5. In Section 7 efficiency measurements
together with main waveforms of the PoE interface and flyback converter are shown.
Figure 1. EVALPM8803-FLY demonstration kit
February 2013
DocID018573 Rev 2
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