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reference designUCC28742

Texas Instruments UCC28742

High-Efficiency Flyback Controller with 1% Output regulation accuracy

Overview

TopologyFlyback Converter
Input voltage85-265 V
Output 15.25 V / 2.1 A
IC revisionB

Description

The UCC28742 off-line flyback controller is a highly integrated, 6-pin secondary-side regulated PWM controller for efficient AC-to-DC power supplies. It is an isolated-flyback power-supply controller that provides Constant-Voltage (CV) using an optical coupler to improve transient response to large-load steps. This device processes information from opto-coupled feedback and an auxiliary flyback winding for high-performance control of output voltage and current.The UCC28742 employs advanced control algorithms to achieve high operating efficiency and performance. The drive output interfaces to a MOSFET power switch. Discontinuous conduction mode (DCM) with valley-switching reduces switching losses. Modulation of switching frequency and primary current-peak amplitude (FM and AM) keeps the conversion efficiency high across the entire load and line ranges.The controller has a maximum switching frequency of 80 kHz and always maintains control of the peak-primary current in the transformer. A minimum switching frequency of 200 Hz facilitates the achievement of low no-load input power.

Features

  • Opto-Coupled Feedback Enables up to 1% Regulation
  • Accurate Current Limit with Overload Timeout Protection and Delayed Hiccup Response
  • Resonant-Ring Valley-Switching Operation for Highest Overall Efficiency
  • 80-kHz Maximum Switching Frequency
  • Frequency Dithering to Ease EMI Compliance
  • Clamped Gate-Drive Output for MOSFET
  • Ultra-Low Start-Up Current and Large VDD Hysteresis
  • High Value Start-Up Resistor
  • Low Bias Capacitance
  • Fault Protections
  • Input Low Line
  • Output Over-Voltage
  • Over-Current
  • Short-Circuit
  • SOT23-6 Package
  • Create a Custom Design Using the UCC28742 with the WEBENCH® Power Designer

Typical applications

  • Power Supply for Cable Modem, Television, SetTop Box, and Wireless Routers, AC-to-DC Power Supply for Appliances
  • Industrial and Medical AC-to-DC Power Supplies, Smart Electricity Meters,Bias Supply for UPS, Server PSU, etc.

More information

Products

Order Code
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fres(MHz)
IR(A)
L(µH)
RDC max.(Ω)
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VT(V (AC))
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Samples
768772221
WE-TI HV Radial Leaded Wire Wound Inductor (High Voltage), 1.3 A, 3.7 MHz
Simu­lation
Downloads9 files

EDA models: Components ZIP

CAD files ZIP

Electric models ZIP

Download all 9 files as zip archive
ZIP

Status Activei| Production is active. Expected lifetime: >10 years.
Product seriesWE-TI HV Radial Leaded Wire Wound Inductor (High Voltage)
Saturation Current1.3 A
Self Resonant Frequency3.7 MHz
Rated Current0.9 A
Inductance220 µH
DC Resistance0.6 Ω
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Length7.8 mm
Width7.8 mm
Height9.5 mm
MountTHT 
744822233
WE-CMB Common Mode Power Line Choke, –, –
Simu­lation
Downloads11 files

EDA models: Components ZIP

CAD files ZIP

Electric models ZIP

Status Activei| Production is active. Expected lifetime: >10 years.
Product seriesWE-CMB Common Mode Power Line Choke
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Rated Current1.5 A
Inductance3300 µH
DC Resistance0.12 Ω
Rated Voltage250 V (AC)
Insulation Test Voltage1500 V (AC)
MaterialMnZn 
Length17.5 mm
Width13 mm
Height22 mm
MountTHT 
750317658
Transformer, –, –
Simu­lation–
Downloads–
Status Activei| Production is active. Expected lifetime: >10 years.
Product series Transformer
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