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TI technology eases implementation of Ethernet-powered devices

Posted: 19 Aug 2005 ?? ?Print Version ?Bookmark and Share

Keywords:texas instruments? ti? power-over-ethernet controller? wlan? tps23750?

Power-over-Ethernet controllerTexas Instruments Inc. (TI) announced its third generation Power-over-Ethernet (PoE) controller technology that promises to ease the implementation of Ethernet-powered devices such as WLAN access points, IP phones, security and RFID scanners.

The TPS23750 IC 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. Requiring a minimum number of external components, this device offers one of the highest levels of performance and flexibility to enable IEEE 802.3af functionality in a powered device.

TI added that the unique 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.

The TPS23750 can withstand voltage transients up to 100V and operates over an industrial temperature range of -40C to 85C. In addition, the device is housed in a PowerPad package with an internal 0.7? 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 a tiny external resistor to set the switching frequency, allowing greater flexibility for power stage component selection. A fixed 140mA 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.

To meet power requirements of certain legacy systems not fully 802.3af-compliant, TI also announced its TPS23770 integrated PD controller, which includes an under-voltage lockout turn-on voltage that is compatible to legacy systems.

Both the TPS23750 and TPS23770 powered device controllers are already available in volume quantities from TI and its authorized distributors. Packaged in a 20-pin, high-power, thin shrink small outline package (HTSSOP), suggested resale pricing for both devices is $1.75 each in quantities of 1,000 units. Evaluation modules of the TPS23750 and TPS23770, complete reference designs, application notes and technical documentation are available through TI's Website.

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