Integrated, green-mode controllers lower operating costs, reduce board space in high-power PoE powered device applications

October 09, 2012 // By Paul Buckley
Texas Instruments Incorporated has introduced two power management integrated circuits that combine a Power over Ethernet powered device (PD) manager with a DC/DC controller.

The TPS23751 and TPS23752 controllers deliver high conversion efficiency over a wide load range and light load efficiency that is 20-percent higher than other solutions on the market.

The ICs are designed for use in IEEE 802.3at type 2 (high-power) compliant PoE designs, used in IP phones, surveillance cameras, wireless access points, as well as various industrial applications.
The new PoE solutions join TI’s family of PD controllers, including the TPS2378 and TPS2379.  The TPS2378 features IEEE 802.3 type 2 compliance and is interoperable with the UPOE Ethernet implementation, which delivers 25.5 W to 51 W over Ethernet CAT-5 cables utilizing the four-pair technique. The TPS2379 delivers higher output power capability with the addition of an external FET to control loads from 50 W to 100 W.

The TPS23751 and TPS23752 generate up to 25.5-W to the PoE loads.  During light load conditions, both devices switch off the synchronous rectifier and go into variable frequency operation. This feature enables efficiencies greater than 80 percent at 20 percent load operation and maintains high efficiency from light to full load.
The circuits include all the features and functions of the TPS2378, as well as an integrated DC/DC controller to convert input voltage to 3.3-V, 5-V or 12-V.
The sleep-mode feature continues generating the maintain power signature after disabling the converter to minimize power consumption.
Evaluation modules (EVMs) are available to help engineers quickly evaluate and design with these devices.

Availability and Pricing

The new high-power PoE controllers and power manager with integrated DC/DC solutions are available to sample and purchase today from TI and its authorized network of distributors. Packaging and suggested retail pricing in 1,000-unit quantities are as follows:

TPS2378 and TPS2379 packaged in a 8-pin SOPowerPAD package costs $1.00 in 1,000-unit quantities.

TPS23751 in a 16-pin TSSOP package costs $1.50 in 1,000-unit quantities.

TPS23752 in a 20-pin TSSOP package costs $1.50 in 1,000-unit quantities.

For more information about TI’s