Rainbow-electronics MAX5940B Manuel d'utilisateur télécharger pdf (Page 13)

MAX5940A/MAX5940B

IEEE 802.3af PD Interface Controller

For Power-Over-Ethernet

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60V

68nF

UVLO

GND

GATE

RCLASS

PGOOD

DC-DC CONVERTER

GND

-48V

WALL

ADAPTER

SUPPLY

GND

V+

VREG

OUT

GATE

DISC

25.5kΩ

SS_SHDN

MAX5014

MAX5940B

LOAD

Typical Application Circuits (continued)

Application Circuit 4

If the wall adapter supply comes up first, it provides

power to the load and pollute the discovery and classi-

fication signatures. If the power-over-ethernet comes

up first, it powers the load until taken over by a wall

adapter with higher output voltage.

Figure 7. Adding Wall Adapter Input Supply (the One with Higher Voltage Provides Power to the Load)

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Rainbow-electronics MAX5940B Manuel d'utilisateur Page 13