Four-output, SEPIC converter-bias power supply reference design for solar panel applications
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Key Document


This reference design supplies two non-isolated and two isolated output voltages. It references a regulated 3.3-V/0.25-A and an unregulated 12-V/0.05-A output on the primary-side, and it isolates two 12-V/0.025-A unregulated outputs.  The design operates over an input voltage range of 7 V to 45 V and offers minimal voltage ringing on the FET for lower stress and reduced EMI.

  • SEPIC topology eliminates FET voltage ringing for reduced stress and lower EMI
  • Four-output single-ended primary-inductor converter (SEPIC) from single transformer provides excellent cross regulation
  • Full load efficiency greater than 80% from 12-V and 24-V input
  • Compact size (30 mm x 40 mm) minimizes required PCB area

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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)7777
Vin (Max) (V)45454545
Vout (Nom) (V)3.3121212
Iout (Max) (A).
Output Power (W).825.6.3.3
TopologySepic- CCMSepic- CCMSepic- CCMSepic- CCM

TI Devices (2)

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Part Number Name Product Family Sample & Buy Design Kits & Evaluation Modules
CSD19538Q2  100V, N ch NexFET MOSFETâ„¢, single SON2x2, 59mOhm  MOSFETs  Sample & Buy Not Available
LM5155-Q1  2.2-MHz wide VIN nonsynchronous boost, flyback, & SEPIC controller  Step-up (boost) regulators  Sample & Buy View Design Kits & Evaluation Modules

CAD/CAE symbols

Part # Package | Pins CAD File (.bxl) STEP Model (.stp)
CSD19538Q2 WSON (DQK)| 6 Download Download
LM5155-Q1 Download Download

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Technical documentation

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User guide (1)
Title Type Size (KB) Date
PDF 3163 08 Oct 2019
Design files (6)
Title Type Size (KB) Date
ZIP 499 08 Oct 2019
ZIP 32183 08 Oct 2019
PDF 617 08 Oct 2019
PDF 99 08 Oct 2019
PDF 97 08 Oct 2019
PDF 134 08 Oct 2019

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