High efficiency 3.3-V/4-A synchronous flyback with hiccup protection reference design
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Key Document


This flyback reference design is for an isolated 15-W low voltage rail. It features a LM5020—100-V wide input flyback controller.  A synchronous secondary rectifier UCC24610 was used for high efficiency. It further enhances the LM5020 with hiccup protection by using a simply discrete circuitry. It is good for low voltage isolated supplies where high efficiency and hiccup protection are needed.

  • 43-V - 57-V in and 3.3-V/4-A out for isolated supplies
  • High efficiency 86.4% reduces thermal dissipation
  • Hiccup protection for enhanced safety and reliability
  • Small solution size: 1" x 1.775" (25.4 mm x 45.1 mm)

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(Output Voltage 1)
Vin (Min) (V)43
Vin (Max) (V)57
Vout (Nom) (V)3.3
Iout (Max) (A)4
Output Power (W)13.2
Input TypeDC
TopologyFlyback- Synchronous

TI Devices (4)

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Part Number Name Product Family Sample & Buy Design Kits & Evaluation Modules
CSD18543Q3A  60V, N ch NexFET MOSFETâ„¢, single SON3x3, 9.9mOhm  MOSFETs  Sample & Buy View Design Kits & Evaluation Modules
LM5020  13-100V Wide Vin, Current Mode PWM Boost, Flyback, Sepic Controller  Step-up (boost) regulators  Sample & Buy View Design Kits & Evaluation Modules
LMV431A  1%, low-voltage (1.24-V) adjustable precision shunt regulator  Voltage references  Sample & Buy Not Available
UCC24610  Secondary side synchronous rectifier controller  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)
CSD18543Q3A VSONP (DNH)| 8 Download Download
LM5020 Download Download
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LMV431A Download Download
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UCC24610 Download Download
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Technical documentation

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User guide (1)
Title Type Size (KB) Date
PDF 2488 04 Jan 2019
Design files (5)
Title Type Size (KB) Date
ZIP 79 04 Jan 2019
PDF 149 04 Jan 2019
PDF 26 04 Jan 2019
PDF 77 04 Jan 2019
PDF 23 04 Jan 2019

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