LPC178* 177*用戶手冊
LPC178x/7x
32-bit ARM Cortex-M3 microcontroller; up to 512 kB flash and
96 kB SRAM; USB Device/Host/OTG; ethernet; LCD; EMC
Rev. 3 — 27 December 2011 Objective data sheet
Power over ethernet (PoE) is a new development thatallows for the delivery of power to ethernet-based devicesvia standard ethernet CAT5 cable, precluding the need forwall adapters or other external power sources. The PoEspecification defines a hardware detection protocol wherePower Sourcing Equipment (PSE) is able to identify PoEPowered Devices (PDs), thus allowing full backwardscompatibility with non-PoE-aware (legacy) ethernetdevices.
To this day, Power over ethernet (PoE) continues to gainpopularity in today’s networking world. The 12.95Wdelivered to the Powered Device (PD) input supplied bythe Power Sourcing Equipment (PSE) is a universal supply.Each PD provides its own DC/DC conversion from anominal 48V supply, thus eliminating the need for a correctvoltage wall adapter. However, higher power devicescan not take advantage of standard PoE because of itspower limitations, and must rely on a large wall adapteras their primary supply. The new LTC4268-1 breaks thispower barrier by allowing for power of up to 35W for suchpower-hungry 2-pair PoE applications. The LTC4268-1provides a complete solution by integrating a high powerPD interface control with an isolated fl yback controller.
