85-VAC - 400-VAC input multiple output flyback reference design


Design files


This offline flyback reference design uses the UCC28700 controller to generate 2 isolated outputs (12 V at 1.2 A, -3.3 V at 10 mA) from an AC input (85 VAC - 400 VAC). The controller provides accurate voltage and current regulation with primary-side feedback, eliminating the need for opto-coupler feedback circuits. The valley-switching technique reduces switching losses and keeps the efficiency high.

  • 85 VAC - 400 VAC input to 2 isolated outputs
  • Valley-switching operation for high overall efficiency
  • Primary-side regulation eleminates opto-coupler
  • Precise control of output voltage and current
Output voltage options PMP30428.1 PMP30428.2
Vin (Min) (V) 85 85
Vin (Max) (V) 400 400
Vout (Nom) (V) 12 -3.3
Iout (Max) (A) 1.1 .01
Output Power (W) 13.2 .033
Isolated/Non-Isolated Isolated Isolated
Input Type AC AC
Topology Flyback- CCM Flyback- CCM

A fully assembled board has been developed for testing and performance validation only, and is not available for sale.

Design files & products

Design files

Download ready-to-use system files to speed your design process.

TIDT048.PDF (9261 K)

Test results for the reference design, including efficiency graphs, test prerequisites and more

TIDRY22.PDF (140 K)

Detailed schematic diagram for design layout and components

TIDRY23.PDF (33 K)

Complete listing of design components, reference designators, and manufacturers/part numbers

TIDRY24.PDF (191 K)

Detailed overview of design layout for component placement

TIDRY26.ZIP (700 K)

Files used for 3D models or 2D drawings of IC components

TIDCF36.ZIP (700 K)

Design file that contains information on physical board layer of design PCB

TIDRY25.PDF (200 K)

PCB layer plot file used for generating PCB design layout


Includes TI products in the design and potential alternatives.

Flyback controllers

UCC28700Constant-voltage, constant-current PWM with PSR & Programmable cable compensation

Data sheet document-pdfAcrobat PDF open-in-new HTML
Linear & low-dropout (LDO) regulators

TPS723200-mA, negative, adjustable low-dropout voltage regulator with enable

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Technical documentation

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Type Title Date
* Test report 85-VAC - 400-VAC Input Multiple Output Flyback Reference Design Dec. 12, 2018

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