Dell N3200-ON EMC Networking N-Series Switches User Guide version 6.6.3 - Page 78

Over-Temperature Protection In addition to the die thermal sensor, there are thermal sensors on each MOSFET that continuously monitor per port main MOSFETs junction temperature and will shut down the port load power in cases where the temperature exceeds 200°C. 4-Pair Ports In order to have the ability to deliver more than 30w to the PD, 4-pair powering is used. 4-pair powering utilizes all eight Registered Jack-45 (RJ-45) wires for delivering the power. It is implemented by utilizing two separate front-ends, each capable of delivering maximum AT power, enabling delivery of 60W over four pairs. The two front ends drive separate pairs and connect together inside the PD. The combined front ends follow certain rules: 1 Line detection: • In case one pair fails pre-detection, the port will turn on as a 2-pair port. • In case both pairs pass pre-detection and fail line detection, the port will not power on. 2 Classification: • PD must have a mechanism that counts the number of class events and determines the PSE type. • 2 class events -PSE is two pairs AT. • 4 class events -PSE is four pairs AT/UPoE. • When one of the classes (or both) is class error, both pairs will not turn on. • When the ports have different class levels, the switch will not turn on any of the pairs. 3 Startup: • Startup of the ports is done simultaneously with maximum gap of 10ms. 4 Port disconnection: 78 Switch Feature Overview