85-480VAC Input, Triple Ouput (12V/0.7A) AC/DC Flyback Reference Design
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Key Document


This reference design generates three separate isolated 12V/0.77A outputs from either an 85-265VAC single phase input or a 200-480VAC-LL three phase input.  The UCC28700 controls a flyback converter power stage.  The primary side regulation feature of the UCC28700 eliminates the need for an optocoupler, reducing cost and complexity.  The three outputs are isolated from each other and can be stacked in series to generate higher output voltages.

  • Accepts 3 phase input voltages up to 480VAC, as well as single phase 85-264VAC
  • Generates three separate isolated 12V/0.7A outputs that can be stacked in series or in parallel for different output voltages/currents
  • Delivers 25W total output power
  • Start-up time <200ms (at 230VAC or higher), <400ms (115VAC
  • Features 960V N-channel power MOSFET switch
  • Primary Side Regulation eliminates optocoupler, reduces cost, increases reliability

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Design Files

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(Output Voltage 1)
Vin (Min) (V)85
Vin (Max) (V)480
Vout (Nom) (V)12
Iout (Max) (A).7
Output Power (W)8.4
Input TypeAC
TopologyFlyback- DCM
Flyback- Non Sync
Flyback- Quasi Resonant

TI Devices (1)

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Part Number Name Product Family Sample & Buy Design Kits & Evaluation Modules
UCC28700  Constant-Voltage, Constant-Current PWM With Primary-Side Regulation  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)
UCC28700 Download Download

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Technical Documents

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User guides (1)
Title Type Size (KB) Date
PDF 5178 01 Sep 2015
Design files (4)
Title Type Size (KB) Date
PDF 255 01 Sep 2015
PDF 61 01 Sep 2015
PDF 81 01 Sep 2015
PDF 155 01 Sep 2015

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