Power over Ethernet

Texas Instruments’ power management integrated circuit (IC) simplifies the design of IEEE Power over Ethernet 802.3af-compliant power source equipment (PSE).

The TPS2384 quad-port power manager can support operation at -40º to +125º C for a wide range of commercial, industrial and military applications such as systems with up to 128 ports to low-port count hub Ethernet switches for small office/home office applications.

The device effectively manages the discovery, classification and delivery of direct-current (DC) power source equipment to a powered device. The IC offers increased flexibility and performance over TI’s TPS2383 PoE manager, introduced in April 2003, while providing necessary power management control and protection. In addition, the TPS2384 also can recognize legacy devices.

A designer can select from three different modes of operation using the TPS2384 device – automatic mode, port-management mode or manual operation. The use of a multi-point or slope detection method for the PD signature resistor allows accurate detection, even when series steering diodes are present. In auto mode, if a proper PD is not detected, the TPS2384 will alert the system to not connect the power. In the port management mode, the host can read the contents of the A2D resistor register after each discovery is completed, and it can set limits for accepting or rejecting the power device. Also while in port-management mode, the TPS2384 can work with a microcontroller to perform advanced power-management functions and detect legacy capacitance loads.

The TPS2384 power manager is available in volume today from TI and its authorized distributors. The device is packaged in a 64-pin HTQFP package. Suggested resale pricing is $6.00 in quantities of 1,000.

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