资料介绍
Power over Ethernet, or PoE, is an increasingly popular way to deliver both power and data over existing Ethernet cable, thus freeing applications from the constraint of AC-power proximity. As the number PoE solutions has grown so has the applications’ appetite for power. A new proprietary standard, LTPoE++™, satisfies this hunger by extending the PoE and PoE+ specifications to 90W of PD delivered power. LTPoE++ also dramatically reduces engineering complexity in power sourcing equipment (PSEs) and powered devices (PDs) when compared to other power-expansion solutions. Plug-and-play simplicity and safe, robust power delivery are hallmarks of LTPoE++. The capabilities of this standard expand the field of Ethernet-powered applications by several orders of magnitude, enabling entirely new classes of PDs, such as power-hungry picocells, base stations or heaters for pan-tilt-zoom cameras.
HISTORY OF PoE
PoE is a standard protocol for sending DC power over copper Ethernet data wiring. The IEEE group that administers the 802.3 Ethernet data standards added PoE capability in 2003. The original PoE spec, known as 802.3af, allowed for 48V DC power at up to 13W. Although the initial specification was widely popular, the 13W cap limited the number of possible applica-tions. In 2009, the IEEE released a new standard, known as 802.3at or PoE+, increasing the voltage and current requirements to supply 25.5W of power.
July 2011 Volume 21 Number 2
I N T H I S
RS485 and RS232
I S S U E
LTPoE++ Extends PoE to 90W with
Reliable and Easy-to-Use Standard
transceivers combined in a
single device 12
Heath Stewart
fast-acting IC protects
sensitive circuits from
overvoltage and reverse Power over Ethernet, or PoE, is an increasingly popular
supply connections 23 way to deliver both power and data over existing Ethernet
cable, thus freeing applications from the const
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