150-VDC - 430-VDC input, multiple output valley-switching flyback reference design
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Key Document


This 10-W non-isolated flyback reference design uses the UCC28742 controller to generate four outputs (5 V at 150 mA, 12 V at 690 mA, 15 V at 80 mA, 18 V at 20 mA). The controller provides constant-voltage and constant-current regulation. Transistors are used in place of an optocoupler feedback circuit to reduce the overall BOM cost.

  • 150-VDC - 430-VDC input to four outputs
  • Protection functions: over voltage, low line, over current and short circuit
  • Resonant valley switching for reduced switching losses
  • Tested design with available design files and test report

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Schematic/Block Diagram

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Design Files

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(Output Voltage 1)
(Output Voltage 2)
(Output Voltage 3)
(Output Voltage 4)
Vin (Min) (V)15015015011
Vin (Max) (V)43043043013
Vout (Nom) (V)1815125
Iout (Max) (A).
Output Power (W).361.28.28.75
TopologyFlyback- Quasi ResonantFlyback- Quasi ResonantFlyback- Quasi ResonantBuck- 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
ATL431LI  Low-IQ programmable shunt regulator offered in an ultra-small DQN package  Voltage references  Sample & Buy View Design Kits & Evaluation Modules
TPS54202  4.5V to 28V Input, 2A Output, EMI Friendly Synchronous Step-Down Converter  Step-down (buck) regulators  Sample & Buy View Design Kits & Evaluation Modules
UCC28742  High-Efficiency Flyback Controller with 1% Output regulation accuracy  Offline & isolated DC/DC controllers & converters  Sample & Buy Not Available

CAD/CAE symbols

Part # Package | Pins CAD File (.bxl) STEP Model (.stp)
ATL431LI Download Download
Download Download
TPS54202 Download Download
UCC28742 Download Download

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Technical documentation

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User guide (1)
Title Type Size (KB) Date
PDF 3630 24 Apr 2020
Design files (6)
Title Type Size (KB) Date
ZIP 1004 24 Apr 2020
ZIP 1004 24 Apr 2020
PDF 169 24 Apr 2020
PDF 135 24 Apr 2020
PDF 68 24 Apr 2020
PDF 372 24 Apr 2020

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