High efficiency, 70-W AC/DC active clamp flyback reference design


Design files


This reference design uses the UCC28780 active clamp flyback controller to generate an isolated output of 20 V @ 3.5 A over an input voltage rage of 90 Vac to 264 Vac. The design also uses the UCC24612 synchronous rectifier controller on the secondary side. Zero voltage switching (ZVS) ensures high efficiency over a wide operating range.

  • Zero voltage switching (ZVS) provides high efficiency (93% peak value)
  • Adaptive burst mode feature maintains high efficiency even at light loads
  • Synchronous rectifier using drain-to-source voltage sensing
Output voltage options PMP30631.1
Vin (Min) (V) 90
Vin (Max) (V) 264
Vout (Nom) (V) 20
Iout (Max) (A) 3.5
Output Power (W) 70
Isolated/Non-Isolated Isolated
Input Type AC
Topology Flyback- Active Clamp
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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.

TIDT139.PDF (2947 K)

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

TIDM214.PDF (235 K)

Detailed schematic diagram for design layout and components

TIDM215.PDF (35 K)

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

TIDM216.PDF (117 K)

Detailed overview of design layout for component placement

TIDM218.ZIP (1151 K)

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

TIDCFM9.ZIP (1169 K)

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

TIDM217.PDF (187 K)

PCB layer plot file used for generating PCB design layout


Includes TI products in the design and potential alternatives.

Flyback controllers

UCC287801-MHz High Frequency Active Clamp Flyback Controller

Data sheet: PDF | HTML
Half-bridge drivers

UCC277121.8-A/2.8-A, 620V half bridge driver with interlock

Data sheet: PDF | HTML
SR & load share controllers

UCC24612High-frequency multi-mode synchronous rectifier controller

Data sheet: PDF | HTML
Shunt voltage references

ATL4312.5-V low-IQ adjustable precision shunt regulator

Data sheet: PDF | HTML

Technical documentation

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Type Title Date
* Test report High Efficiency, 70-W AC/DC Active Clamp Flyback Reference Design Sep. 26, 2019

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