Primary Side Regulated Flyback Reference Design with 120VAC Input and 24V/4A Rated Output
This product has been released to the market and is available for purchase. For some products, newer alternatives may be available.

Description & Features

Technical documentation

Support & Training

Order Now

See the Important Notice and Disclaimer covering reference designs and other TI resources.

Key Document


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

See the Important Notice and Disclaimer covering reference designs and other TI resources.


Schematic/Block Diagram

Quickly understand overall system functionality.

Download Schematic

Design Guide

Get results faster with test and simulation data that's been verified.

Download Design Guide

Design Files

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

Download Design Files

(Output Voltage 1)
Vin (Min) (V)100
Vin (Max) (V)138
Vout (Nom) (V)24
Iout (Max) (A)4
Output Power (W)96
Input TypeAC
TopologyFlyback- DCM

TI Devices (1)

Order samples, get tools and find more information on the TI products in this reference design.

Part Number Name Product Family Sample & Buy Design Kits & Evaluation Modules
UCC28630  High power Flyback controller with PSR, peak power mode, X-Cap discharge, and freq dither  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)
UCC28630 Download

Texas Instruments and Accelerated Designs, Inc. have collaborated together to provide TI customers with schematic symbols and PCB layout footprints for TI products.

Step 1: Download and install the free download.

Step 2: Download the Symbol and Footprint from the CAD.bxl file table.

Technical documentation

See the Important Notice and Disclaimer covering reference designs and other TI resources.

User guide (1)
Title Type Size (KB) Date
PDF 1344 20 Oct 2015
Design files (3)
Title Type Size (KB) Date
PDF 166 13 Nov 2015
PDF 140 13 Nov 2015
PDF 176 13 Nov 2015

Support & training

TI E2E™ forums with technical support from TI engineers

Search our extensive online knowledge base where millions of technical questions and answers are available 24/7.

Search answers from TI experts

Content is provided 'AS IS' by the respective TI and Community contributors and does not constitute TI specifications.
See terms of use.

If you have questions about quality, packaging, or ordering TI products visit our Support page.

Technical articles