Ethernet power

Texas Instruments

has disclosed details of its third generation Power-over-Ethernet controller.

Its TPS23750 device combines the functionality of TI's TPS2375 powered device (PD) controller with a primary side DC/DC pulse-width modulation (PWM) controller to effectively manage discovery, classification and delivery of direct-current (DC) power to an end appliance.

The controller supports non-isolated or isolated power supply topologies required by WLAN access point systems, IP phones and other systems, including flyback, forward or non-synchronous low-side buck topologies. It can withstand voltage transients up to 100V and operates over an industrial temperature range of -40º C to 85º C.

In addition, it is housed in a PowerPad package with an internal 0.7-ohm FET to minimize heat dissipation in the system. The TPS23750 also protects the powered system through thermal shutdown and current limiting.

The integrated device relies on an external resistor to set the switching frequency, allowing greater flexibility for power stage component selection. A fixed 140-mA of in-rush current limit also eases powered device startup. The TPS23750's power conversion functionality includes many additional protection features, such as programmable soft start, hiccup-type fault limiting, a 50 percent maximum duty cycle and a true-voltage output error amplifier.