Primary Side Regulated Flyback Reference Design with 120VAC Input and 24V/4A Rated Output


Design files


This reference design implements the UCC28630 PSR controller in a flyback power supply. The UCC28630 is capable of operating in both Continuous and Discontinuous Conduction Modes which enables high efficiency while reducing inductor size and cost. Safety standards such as EN60950 require that any X-capacitors in EMC filters on the AC side of the bridge rectifier quickly discharge to a safe level when AC is disconnected.  Typically, this requirement is achieved by including a resistive discharge element in parallel with the X-capacitor. However, this resistance causes a continuous power dissipation that impacts the standby power performance. In order to reduce standby power and eliminate the standing loss associated with the conventional discharge resistors, the UCC28630 device incorporates active X-capacitor discharge circuitry. In this design, less than 100mW no load power comsumption and over 88% converter efficiency is achieved.

  • Utilize UCC28630 CCM/DCM PSR controller
  • Over 86% average efficiency
  • Optimized US line AC-DC power supply design
  • 24V/4A rated output
  • This circuit is tested and includes a test report
Output voltage options PMP10804.1
Vin (Min) (V) 100
Vin (Max) (V) 138
Vout (Nom) (V) 24
Iout (Max) (A) 4
Output Power (W) 96
Isolated/Non-Isolated Isolated
Input Type AC
Topology Flyback- DCM
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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.

TIDUAY4.PDF (1376 K)

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


Detailed schematic diagram for design layout and components


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


Detailed overview of design layout for component placement


Includes TI products in the design and potential alternatives.

Flyback controllers

UCC28630High power Flyback controller with PSR, peak power mode, X-Cap discharge, and freq dither

Data sheet: PDF | HTML

Technical documentation

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Type Title Date
* Test report PMP10804 Test Results Oct. 20, 2015

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