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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WEBENCH ® Designer UCC28740

 AC  DC  
AC Frequency  60 Hz  50 Hz
Use Isolated Output?
Rectification Type
  Min   Max Range
VinRMS -  V
Vout  V
Iout  A
Ambient Temp  °C

Parametrics

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Part number Order 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 Order now Secondary-side regulation     99     100     21/7.75     SSR
HV Start-up
DCM    
-40 to 125     SOIC | 7     Catalog     7SOIC: 29 mm2: 6 x 4.9 (SOIC | 7)    
LM5023 Order now Secondary-side regulation     100     130     12.8/7.5     Quasi-Resonant
SSR
Green Mode
Light Load Efficiency    
-40 to 125     VSSOP | 8     Catalog     8VSSOP: 15 mm2: 4.9 x 3 (VSSOP | 8)    
UCC28600 Order now Secondary-side regulation     99     130     10.3/9.3     SSR
Quasi-Resonant
Error Amplifier
Green Mode
Light Load Efficiency    
-40 to 105     SOIC | 8     Catalog     8SOIC: 19 mm2: 3.91 x 4.9 (SOIC | 8)    
UCC28610 Order now Secondary-side regulation     100     130     10.2/8     SSR
HV Start-up
DCM    
-40 to 125     PDIP | 8
SOIC | 8    
Catalog     8PDIP: 93 mm2: 9.43 x 9.81 (PDIP | 8)
8SOIC: 19 mm2: 3.91 x 4.9 (SOIC | 8)    
UCC28700 Order now Primary-side regulation     99     132     21/8.1     PSR
DCM    
-20 to 125     SOT-23 | 6     Catalog     6SOT-23: 5 mm2: 1.6 x 2.9 (SOT-23 | 6)    
UCC28704 Order now Primary-side regulation     99     85     21/7.7     PSR
DCM    
-40 to 125     SOT-23 | 6     Catalog     6SOT-23: 5 mm2: 1.6 x 2.9 (SOT-23 | 6)    
UCC28710 Order now Primary-side regulation     99     100     21/8     PSR
DCM
HV Start-up
Green Mode
Input Line Monitor
Leading Edge Blanking
Light Load Efficiency
Low Power
Soft Start    
-40 to 125     SOIC | 7     Catalog     7SOIC: 29 mm2: 6 x 4.9 (SOIC | 7)    
UCC28720 Order now Primary-side regulation     99     80     21/7.7     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    
-40 to 125     SOIC | 7     Catalog     7SOIC: 29 mm2: 6 x 4.9 (SOIC | 7)    
UCC28722 Order now Primary-side regulation     99     80     21/7.7     PSR
DCM    
-40 to 125     SOT-23 | 6     Catalog     6SOT-23: 5 mm2: 1.6 x 2.9 (SOT-23 | 6)