70-W flyback and 37-W boost power reference design
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Key Document


This reference design uses two LM5155 devices to make a flyback and boost power stage. The flyback creates an isolated 28 Vdc bus from a 24 +/-10% Vdc bus and the boost creates a 37 Vdc bus from the output of the flyback. The flyback can be loaded up to 70 W and the boost can be loaded up to 37-W. All components are placed on one side of the board to reduce assembly complexity and cost. Both power stages achieve over 90% efficiency across output conditions.

  • High efficiency flyback and boost power stage
  • Compact size (2" x 3.75") minimizes solution size area
  • Single-side assembly and 2-layer PCB for reduced manufacturing costs

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(Output Voltage 1)
(Output Voltage 2)
Vin (Min) (V)1827
Vin (Max) (V)2929
Vout (Nom) (V)2837
Iout (Max) (A)2.51
Output Power (W)7037
Input TypeDCDC
TopologyFlyback- CCMBoost- Non Sync

TI Devices (2)

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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
LM5155  2.2MHz wide VIN non-synchronous boost controller  Step-up (boost) regulators  Sample & Buy View Design Kits & Evaluation Modules

CAD/CAE symbols

Part # Package | Pins CAD File (.bxl) STEP Model (.stp)
ATL431LI Download Download
Download Download
LM5155 Download Download

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Technical documentation

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User guide (1)
Title Type Size (KB) Date
PDF 2683 19 Nov 2019
Design files (6)
Title Type Size (KB) Date
ZIP 449 19 Nov 2019
ZIP 880 19 Nov 2019
PDF 587 19 Nov 2019
PDF 131 19 Nov 2019
PDF 292 19 Nov 2019
PDF 165 19 Nov 2019

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