TIDUF57 November   2023

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
    1. 1.1 Key System Specifications
  8. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations {Required Topic}
    3. 2.3 Highlighted Products
      1. 2.3.1 LMG3624
  9. 3System Design Theory
    1. 3.1 Quasi-Resonant Operation
    2. 3.2 Transformer Design
    3. 3.3 GaN FET Switching Device
    4. 3.4 Current Sense Emulation Resistor
  10. 4Hardware, Testing Requirements, and Test Results
    1. 4.1 Required Hardware
      1. 4.1.1 Hardware
      2. 4.1.2 Testing Equipment
    2. 4.2 Test Setup
    3. 4.3 Test Results
      1. 4.3.1 Efficiency Results
      2. 4.3.2 Thermal Results
      3. 4.3.3 Switching Waveforms
      4. 4.3.4 Switching Transients
  11. 5Design and Documentation Support
    1. 5.1 Design Files
      1. 5.1.1 Schematics
      2. 5.1.2 BOM
    2. 5.2 Tools and Software
    3. 5.3 Documentation Support {Required Topic}
    4. 5.4 Support Resources
    5. 5.5 Trademarks
  12. 6About the Author

Description

This reference design is a 65-W, USB power delivery (PD) 3.0 adapter targeted for many charging applications including mobile phones, laptops, and tablets. The design achieves high efficiency and power density with the use of integrated gallium nitride (GaN) technology. High efficiency is enabled with the quasi-resonant flyback, which provides a balance between simplicity and low switching losses. The quasi-resonant scheme varies the switching frequency across line and load, while making sure that the primary field-effect transistor (FET) switches at the lowest possible drain voltage. To further increase the efficiency, the integrated sense emulation of the GaN device provides virtually lossless current sensing. High power density is enabled by the high-frequency capability of the integrated GaN device, which enables a smaller inductance, smaller core size, and reduction in the total number of primary windings.