SLUSBE8B May   2013  – September 2015 UCC28720

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Detailed Pin Description
    4. 7.4 Device Functional Modes
      1. 7.4.1 Primary-Side Voltage Regulation
      2. 7.4.2 Primary-Side Current Regulation
      3. 7.4.3 Valley Switching
      4. 7.4.4 Start-Up Operation
      5. 7.4.5 Fault Protection
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Stand-by Power Estimate
        2. 8.2.2.2 Input Bulk Capacitance and Minimum Bulk Voltage
        3. 8.2.2.3 Transformer Turns Ratio, Inductance, Primary-Peak Current
        4. 8.2.2.4 Transformer Parameter Verification
        5. 8.2.2.5 Output Capacitance
        6. 8.2.2.6 VDD Capacitance, CDD
        7. 8.2.2.7 VS Resistor Divider, Line Compensation, and Cable Compensation
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Device Nomenclature
        1. 11.1.1.1 Definition of Terms
          1. 11.1.1.1.1  Capacitance Terms in Farads
          2. 11.1.1.1.2  Duty Cycle Terms
          3. 11.1.1.1.3  Frequency Terms in Hertz
          4. 11.1.1.1.4  Current Terms in Amperes
          5. 11.1.1.1.5  Current and Voltage Scaling Terms
          6. 11.1.1.1.6  Transformer Terms
          7. 11.1.1.1.7  Power Terms in Watts
          8. 11.1.1.1.8  Resistance Terms in Ω
          9. 11.1.1.1.9  Timing Terms in Seconds
          10. 11.1.1.1.10 Voltage Terms in Volts
          11. 11.1.1.1.11 AC Voltage Terms in VRMS
          12. 11.1.1.1.12 Efficiency Terms
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Community Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

9 Power Supply Recommendations

The UCC28720 is intended for AC/DC adapters and chargers with input voltage range of 85 VAC(rms) to 265 VAC(rms) using Flyback topology. It can be used in other applications and converter topologies with different input voltages. Be sure that all voltages and currents are within the recommended operating conditions and absolute maximum ratings of the device. To maintain output current regulation over the entire input voltage range, design the converter to operate close to fMAX when in full-load conditions. To improve thermal performance increase the copper area connected to GND pins.