Datasheet

TPS2379

SLVSB98 –MARCH 2012

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Auxiliary Pass MOSFET Control

The TPS2379 can be used in non-standard applications requiring power significantly above the IEEE802.3at,

type 2 levels. This implementation can be achieved by utilizing all four Ethernet wire pairs and boosting the

TPS2379 hotswap MOSFET operating current limit. Boosting the TPS2379 operating current limit is achieved by

adding an external pass MOSFET to share the total load current with the internal hotswap MOSFET. The

external pass MOSFET is enabled by the GATE pin after the internal hotswap MOSFET inrush is complete. The

GATE pin will de-assert if the TPS2379 internal current limit is exceeded in excess of 300 µs.

A comprehensive high power POE design example is discussed in application report Implementing a 60-W, End-

to-End PoE System (literature number SLVA498).

Using DEN to Disable PoE

The DEN pin may be used to turn the PoE hotswap switch off by pulling it to VSS while in the operational state,

or to prevent detection when in the idle state. A low voltage on DEN forces the hotswap MOSFET off during

normal operation.

Product Folder Link(s) :TPS2379