TIDUF59 March   2024

 

  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
      1. 2.2.1 PFC Inductance Design
      2. 2.2.2 Configuration of CS pin in LMG3622
      3. 2.2.3 AHB Topology and the VCC Design
      4. 2.2.4 LMG2610 for AHB Topology
    3. 2.3 Highlighted Products
      1. 2.3.1 UCC28056
      2. 2.3.2 LMG3622
      3. 2.3.3 LMG2610
  9. 3Hardware, Test Requirements, and Test Results
    1. 3.1 Hardware
    2. 3.2 Test Setup
    3. 3.3 Test Results
      1. 3.3.1 Switching Waveform
        1. 3.3.1.1 Switching Waveform on the PFC Stage
        2. 3.3.1.2 Switching Waveform on the AHB Stage
      2. 3.3.2 Efficiency Test Result
      3. 3.3.3 Thermal Test Result
  10. 4Design and Documentation Support
    1. 4.1 Design Files
      1. 4.1.1 Schematics
      2. 4.1.2 BOM
      3. 4.1.3 Layout Prints {Optional Section}
    2. 4.2 Tools
    3. 4.3 Documentation Support
    4. 4.4 Support Resources
    5. 4.5 Trademarks
  11. 5About the Author

2.1 Block Diagram

The system is combined of 2 parts, the PFC stage and DC-DC stage.

The PFC stage is designed with the UCC28056, eliminating the AUX winding on the LPFC to simplify the design. The LMG3622 can drive the PFC at higher frequencies to reduce the size of the LPFC with higher efficiency and density.

The DC-DC stage was designed with AHB topology providing the flexibility of the output voltage range and ZVS for high efficiency. The LMG2610 half-bridge GaN device with integrated low-side 170mΩ, high-side 248mΩ GaN-FET driver, level shift, and GaN-based bootstrap diode inside a 7mm × 9mm package size helps minimize the PCB size.

Instead of a USB PD controller, the feedback system is designed with the TL431 featuring a resistor divider array which sets the output voltage with a jumper.

GUID-20231208-SS0I-90DZ-2XNT-VVWQNMLDG0ZW-low.svg Figure 2-1 System Block Diagram of 140W Reference Design