UCC28740 Constant-Voltage, Constant-Current Flyback Controller Using Opto-Coupler Feedback | TI.com

UCC28740 (ACTIVE)

Constant-Voltage, Constant-Current Flyback Controller Using Opto-Coupler Feedback

 

Different variations available

Make sure you have the right SSR flyback per your requirements

  • SOIC-7 package with integrated high voltage startup -  UCC28740
  • SOT-23 package with resistive startup -  UCC28742

Description

The UCC28740 isolated-flyback power-supply controller provides Constant-Voltage (CV) using an optical coupler to improve transient response to large-load steps. Constant-Current (CC) regulation is accomplished through Primary-Side Regulation (PSR) techniques. This device processes information from opto-coupled feedback and an auxiliary flyback winding for precise high-performance control of output voltage and current.

An internal 700-V startup switch, dynamically controlled operating states, and a tailored modulation profile support ultra-low standby power without sacrificing startup time or output transient response.

Control algorithms in the UCC28740 allow operating efficiencies to meet or exceed applicable standards. 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 100 kHz and always maintains control of the peak-primary current in the transformer. Protection features keep primary and secondary component stresses in check. A minimum switching frequency of 170 Hz facilitates the achievement of less than 10-mW no-load power.

Features

  • Less than 10-mW No-Load Power Capability
  • Optocoupled Feedback for CV, and
    Primary-Side Regulation (PSR) for CC
  • Enables ±1% Voltage Regulation and ±5% Current Regulation Across Line and Load
  • 700-V Startup Switch
  • 100-kHz Maximum Switching Frequency Enables High-Power-Density Charger Designs
  • Resonant-Ring Valley-Switching Operation for Highest Overall Efficiency
  • Frequency Dithering to Ease EMI Compliance
  • Clamped Gate-Drive Output for MOSFET
  • Overvoltage, Low-Line, and Overcurrent Protection Functions
  • SOIC-7 Package
  • Create a Custom Design Using the UCC28740 With the WEBENCH® Power Designer

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Parametrics Compare all products in Flyback controllers

 
Control method
Duty cycle (Max) (%)
Frequency (Max) (kHz)
UVLO thresholds on/off (V)
Features
Operating temperature range (C)
Package Group
Rating
Package size: mm2:W x L (PKG)
UCC28740 LM5023 UCC28600 UCC28610 UCC28700 UCC28704 UCC28710 UCC28720 UCC28722 UCC28742 UCC28780
Secondary-side regulation     Secondary-side regulation     Secondary-side regulation     Secondary-side regulation     Primary-side regulation     Primary-side regulation     Primary-side regulation     Primary-side regulation     Primary-side regulation     Secondary-side regulation     Secondary-side regulation    
99     100     99     100     99     99     99     99     99     99     99    
100     130     130     130     132     85     100     80     80     105     1000    
21/7.75     12.8/7.5     10.3/9.3     10.2/8     21/8.1     21/7.7     21/8     21/7.7     21/7.7     22/7.7     17.5/10    
SSR
HV Start-up
DCM    
Quasi-Resonant
SSR
Green Mode
Light Load Efficiency    
SSR
Quasi-Resonant
Error Amplifier
Green Mode
Light Load Efficiency    
SSR
HV Start-up
DCM    
PSR
DCM    
PSR
DCM    
PSR
DCM
HV Start-up
Green Mode
Input Line Monitor
Leading Edge Blanking
Light Load Efficiency
Low Power
Soft Start    
PSR
DCM
HV Start-up
Current Limiting
Green Mode
HV Start-up
Input Line Monitor
Leading Edge Blanking
Light Load Efficiency
Low Power
Soft Start    
PSR
DCM    
SSR
DCM    
SSR
Zero Voltage Switching    
-40 to 125     -40 to 125     -40 to 105     -40 to 125     -20 to 125     -40 to 125     -40 to 125     -40 to 125     -40 to 125     -40 to 125     -40 to 125    
SOIC | 7     VSSOP | 8     SOIC | 8     PDIP | 8
SOIC | 8    
SOT-23 | 6     SOT-23 | 6     SOIC | 7     SOIC | 7     SOT-23 | 6     SOT-23 | 6     SOIC | 16
WQFN | 16    
Catalog     Catalog     Catalog     Catalog     Catalog     Catalog     Catalog     Catalog     Catalog     Catalog     Catalog    
7SOIC: 29 mm2: 6 x 4.9 (SOIC | 7)     8VSSOP: 15 mm2: 4.9 x 3 (VSSOP | 8)     8SOIC: 19 mm2: 3.91 x 4.9 (SOIC | 8)     See datasheet (PDIP)
8SOIC: 19 mm2: 3.91 x 4.9 (SOIC | 8)    
6SOT-23: 8 mm2: 2.8 x 2.9 (SOT-23 | 6)     6SOT-23: 8 mm2: 2.8 x 2.9 (SOT-23 | 6)     7SOIC: 29 mm2: 6 x 4.9 (SOIC | 7)     7SOIC: 29 mm2: 6 x 4.9 (SOIC | 7)     6SOT-23: 8 mm2: 2.8 x 2.9 (SOT-23 | 6)     6SOT-23: 8 mm2: 2.8 x 2.9 (SOT-23 | 6)     16SOIC: 59 mm2: 6 x 9.9 (SOIC | 16)
16WQFN: 9 mm2: 3 x 3 (WQFN | 16)    

Design tool

WEBENCH® Designer UCC28740

 AC  DC  
AC Frequency  60 Hz  50 Hz
Use Isolated Output?
Flavor
  Min   Max Range
VinRMS  V 85.00 to 480.00V
Vout  V 3.3 to 25.0V
Iout  A ≤ 10.0A
Ambient Temp  °C -40 to 125°C
Use Synchronous Rectifier