12-V/30-mA output, high-efficiency neutral-less upside-down buck AC/DC power supply reference design
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Key Document


This reference design uses the UCC28910 in an upside-down buck topology to make a 12-V output capable of 30-mA loading from a 120-Vac input. The design achieves more than 70% efficiency at full loading. All components are placed on one side of the board to reduce assembly complexity and cost. The overall board dimensions are 1.35 inches by 1.35 inches with a max height of 0.3 inches (excluding test points). The floating output stays within 1% regulation across loading conditions.

  • More than 70% efficiency at full load
  • Less than 1% regulation across output loading
  • Compact solution size of 1.35 inches by 1.35 inches by 0.3 inches
  • Adjustable current limit

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Schematic/Block Diagram

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Design Files

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(Output Voltage 1)
Vin (Min) (V)108
Vin (Max) (V)132
Vout (Nom) (V)12
Iout (Max) (A).03
Output Power (W).36
Input TypeAC
TopologyBuck- Upside Down

TI Devices (1)

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Part Number Name Product Family Sample & Buy Design Kits & Evaluation Modules
UCC28910  700V Flyback switcher with constant-voltage constant-current and primary-side control  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)
UCC28910 Download Download

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Technical documentation

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User guides (1)
Title Type Size (KB) Date
PDF 1330 28 Jan 2020
Design files (6)
Title Type Size (KB) Date
ZIP 289 09 Sep 2019
ZIP 405 09 Sep 2019
PDF 224 09 Sep 2019
PDF 52 09 Sep 2019
PDF 280 09 Sep 2019
PDF 101 09 Sep 2019

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