The TPS23785B is a combined Power over Ethernet (PoE) powered device (PD) interface and current-mode DC-to-DC controller optimized specifically for non-isolated converters. The PoE interface supports the IEEE 802.3at standard.
The TPS23785B supports a number of input voltage ORing options including highest voltage, external adapter preference, and PoE preference. These features allow the designer to determine which power source will carry the load under all conditions.
The PoE interface features the two-event, physical-layer classification necessary for compatibility with high-power midspan power sourcing equipment (PSE) per IEEE 802.3at. The detection signature pin can also be used to force power from the PoE source off. Classification can be programmed to any of the defined types with a single resistor.
The DC-to-DC controller features two complementary gate drivers with programmable dead time. This simplifies design for highly-efficient flyback topologies utilizing secondary synchronous rectification. The second gate driver may be disabled if desired for single MOSFET topologies. The controller also features internal softstart, bootstrap startup source, current-mode compensation, and a 78% maximum duty cycle. A programmable and synchronizable oscillator allows design optimization for efficiency and eases use of the controller to upgrade existing power supply designs. Accurate programmable blanking, with a default period, simplifies the usual current-sense filter design trade-offs.
Special note
Active – Limited TI design support
This product has limited direct TI design support for existing projects. If available, you can find relevant collateral and software on the product folder. For existing designs using this product, you may request support in the TI E2E support forums, but limited support is available for this product.
| Type | Title | Date | ||
|---|---|---|---|---|
| * | Data sheet | High-Power, High-Efficiency PoE PD and DC-to-DC Controller datasheet (Rev. A) | 18 Dec 2012 | |
| Application note | Lightning Surge Considerations for PoE Powered Devices | 30 Apr 2015 | ||
| User guide | TPS23785BEVM-522 Evaluation Module | 25 Apr 2014 | ||
| Application note | Efficiency-Optimized, Synchronous Flyback, High-Power PoE Controller/Converter | 17 Jan 2012 | ||
| Application note | High Efficiency Class 4 PoE Powered Device | 23 Mar 2011 | ||
| Application note | Advanced Adapter ORing Solutions using the TPS23753 (Rev. A) | 09 Feb 2009 | ||
| Application note | Designing an EMI Compliant PoE with Isolated Flyback | 20 May 2008 |
For additional terms or required resources, click any title below to view the detail page where available.
The flyback converter with synchronous reftifier provides excellent efficiency and small size for PoE (...)
| Package | Pins | Download |
|---|---|---|
| HTSSOP (PWP) | 24 | View options |
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