UM1062 Datasheet, PDF (1/31 Pages) STMicroelectronics – The PM8803 is a highly integrated device embedding

UM1062
User manual
EVALPM8803-FWD: IEEE802.3at compliant demonstration kit
with synchronous active clamp forward converter
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-FWD PoE+ demonstration board. The
same PCB can be populated with different components to support various configurations
and options (active clamp forward both with synchronous rectification or with diode
rectification).
This document focuses on a reference design for PoE+ based on AC forward topology with
synchronous rectification, with the PM8803 as the main controller.
The schematics and board layout of the PoE+ section 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 AC forward converter are shown.
Figure 1. EVALPM8803-FWD demonstration kit
March 2011
Doc ID 018571 Rev 1
1/31
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