SLUSFF2 October   2024 UCG28826

ADVANCE INFORMATION  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Detailed Pin Descriptions
      1. 6.3.1  HV - High Voltage Input
      2. 6.3.2  SW - Switch Node
      3. 6.3.3  GND – Ground Return
      4. 6.3.4  FLT - External Overtemperature Fault
      5. 6.3.5  FB ­­– Feedback
      6. 6.3.6  TR - Turns Ratio
      7. 6.3.7  IPK - Peak Current and Dithering
      8. 6.3.8  FCL - Frequency clamp and fault response
      9. 6.3.9  CDX - CCM, drive strength and X-cap discharge
      10. 6.3.10 VCC - Input Bias
    4. 6.4 Feature Description
      1. 6.4.1  Self Bias and Auxless Sensing
      2. 6.4.2  Control Law
        1. 6.4.2.1 Valley Switching
        2. 6.4.2.2 Frequency Foldback
        3. 6.4.2.3 Burst Mode
        4. 6.4.2.4 Continuous Conduction Mode (CCM)
      3. 6.4.3  GaN HEMT Switching Capability
      4. 6.4.4  Soft Start
      5. 6.4.5  Frequency Clamp
      6. 6.4.6  Frequency Dithering
      7. 6.4.7  Slew Rate Control
      8. 6.4.8  Transient Peak Power Capability
      9. 6.4.9  X-Cap Discharge
      10. 6.4.10 Fault Protections
        1. 6.4.10.1 Brownout Protection
        2. 6.4.10.2 Short-Circuit Protection
        3. 6.4.10.3 Output Over Voltage Protection
        4. 6.4.10.4 Over Power Protection (OPP, LPS)
        5. 6.4.10.5 Overtemperature Protection
        6. 6.4.10.6 Open FB Protection
        7. 6.4.10.7 Error Codes for Protections
  8. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Application
      1. 7.2.1 Design Requirements
      2. 7.2.2 Detailed Design Procedure
        1. 7.2.2.1 Input Bulk Capacitor
        2. 7.2.2.2 Transformer Primary Inductance and Turns Ratio
        3. 7.2.2.3 Output Capacitor
        4. 7.2.2.4 Selection Resistors
      3. 7.2.3 Application Curves
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
      2. 7.4.2 Layout Example
  9. 8 Device and Documentation Support
    1. 8.1 Device Support
    2. 8.2 Documentation Support
      1. 8.2.1 Related Documentation
    3. 8.3 Receiving Notification of Documentation Updates
    4. 8.4 Support Resources
    5. 8.5 Trademarks
    6. 8.6 Electrostatic Discharge Caution
    7. 8.7 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information
    1. 10.1 Package Option Addendum
    2. 10.2 Mechanical Data

7.2.3 Application Curves

The figures below are measured on the 65W, universal input evaluation module for UCG28826. The waveforms show switching at different valleys for different output powers, frequency foldback and burst mode operation and no-load to full load transients with 20V and 5V output.

Yellow: SW node, Green: Input bulk capacitor voltage, Pink: FB pin voltage

UCG28826 1st Valley and 2nd Valley Operation at 115VACFigure 7-2 1st Valley and 2nd Valley Operation at 115VAC
UCG28826 4th Valley Operation at 230VACFigure 7-4 4th Valley Operation at 230VAC
UCG28826 6th Valley Operation at 230VACFigure 7-6 6th Valley Operation at 230VAC
UCG28826 Burst Mode at 230VACFigure 7-8 Burst Mode at 230VAC
UCG28826 Load transient at 230VAC and 5V output
Note: Green: VOUT, Pink: Output current
Figure 7-10 Load transient at 230VAC and 5V output
UCG28826 3rd Valley Operation at 230VACFigure 7-3 3rd Valley Operation at 230VAC
UCG28826 5th Valley Operation at 230VACFigure 7-5 5th Valley Operation at 230VAC
UCG28826 Frequency Foldback Mode at 230VACFigure 7-7 Frequency Foldback Mode at 230VAC
UCG28826 Load transient at 230VAC and 20V output
Note: Green: VOUT, Pink: Output current
Figure 7-9 Load transient at 230VAC and 20V output