Class 2 Mulitple Output, High Efficiency Flyback Converter for PoE Applications
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This reference evaluation module, featuring the TPS23785B PoE interface and DC-toDC contoller, is used for class 2 PoE applications where high effliency and multiple outputs are required.

The flyback converter with synchronous reftifier provides excellent efficiency and small size for PoE applications such as IP phones. The TPS23785B contains both the PoE powered device and the PWM contoller.

  • Efficiency achieved >90%
  • 1.5% peak to peak cross regulation on 5V
  • Isolated multiple output (3.3V at 0.88A; 5V at 0.35A; 10V at 0.11A)
  • Uses TPS23785B high-power, high-efficiency PoE PD and DC-to-DC controller
  • Small board size
  • This circuit design is fully functional and tested and recommended for new design.

See the Important Notice and Disclaimer covering reference designs and other TI resources.


Schematic/Block Diagram

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Design Files

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(Output Voltage 1)
(Output Voltage 2)
(Output Voltage 3)
Vin (Min) (V)363636
Vin (Max) (V)575757
Vout (Nom) (V)3.3510
Iout (Max) (A).88.35.11
Output Power (W)2.9041.751.1
Input TypeDCDCDC
TopologyFlyback- Synchronous
Flyback- Synchronous
Flyback- Synchronous

TI Devices (3)

Order samples, get tools and find more information on the TI products in this reference design.

Part Number Name Product Family Sample & Buy Design Kits & Evaluation Modules
CSD17527Q5A  30-V, N channel NexFET™ power MOSFET, single SON 5 mm x 6 mm, 10.8 mOhm  MOSFETs  Sample & Buy Not Available
TLV431A  1% accuracy, low-voltage, adjustable precision shunt regulator  Voltage references  Sample & Buy View Design Kits & Evaluation Modules
TPS23785B  High-Power, High-Efficiency PoE PD and DC-to-DC Controller  Power over Ethernet (PoE) ICs  Sample & Buy Not Available

CAD/CAE symbols

Part # Package | Pins CAD File (.bxl) STEP Model (.stp)
CSD17527Q5A VSONP (DQJ)| 8 Download Download
TLV431A Download Download
Download Download
Download -
Download Download
Download -
Download Download
TPS23785B Download

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Technical documentation

See the Important Notice and Disclaimer covering reference designs and other TI resources.

User guide (1)
Title Type Size (KB) Date
PDF 648 16 Sep 2013
Design files (4)
Title Type Size (KB) Date
ZIP 313 16 Sep 2013
PDF 225 16 Sep 2013
PDF 121 16 Sep 2013
PDF 61 16 Sep 2013

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