180-VAC - 264-VAC input multiple output flyback reference design
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Key Document


This offline flyback reference design uses the UCC28740 controller to generate 3 isolated outputs (5 V at 30 mA, 15 V at 20 mA, 15 V at 20 mA) from an AC input (180 VAC - 264 VAC). The design can provide 750-mW output power. The UCC28740 uses an optical coupler to regulate the 5-V output and to improve transient response. The valley-switching technique reduces switching losses and keeps the efficiency high.

  • 180 VAC - 264 VAC input to 3 isolated outputs
  • Valley-switching operation for highest overall efficiency
  • Optocoupled feedback for constant voltage regulation

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Design Files

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(Output Voltage 1)
(Output Voltage 2)
(Output Voltage 3)
Vin (Min) (V)180180180
Vin (Max) (V)264264264
Vout (Nom) (V)15155
Iout (Max) (A).02.02.03
Output Power (W).3.3.15
Input TypeACACAC
TopologyFlyback- Quasi ResonantFlyback- Quasi ResonantFlyback- Quasi Resonant

TI Devices (2)

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Part Number Name Product Family Sample & Buy Design Kits & Evaluation Modules
ATL431  2.5-V low-IQ adjustable precision shunt regulator  Voltage references  Sample & Buy View Design Kits & Evaluation Modules
UCC28740  Constant-voltage, constant-current Flyback controller Using Opto-Coupler Feedback  Offline & isolated DC/DC controllers & converters  Sample & Buy View Design Kits & Evaluation Modules

CAD/CAE symbols

Part # Package | Pins CAD File (.bxl) STEP Model (.stp)
ATL431 Download Download
UCC28740 Download Download

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Technical documentation

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User guide (1)
Title Type Size (KB) Date
PDF 12111 30 Nov 2018
Design files (6)
Title Type Size (KB) Date
ZIP 153 30 Nov 2018
ZIP 719 30 Nov 2018
PDF 172 30 Nov 2018
PDF 166 30 Nov 2018
PDF 31 30 Nov 2018
PDF 150 30 Nov 2018

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