TIDUFF4 October   2025

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
    1. 1.1 Key System Specifications
      1. 1.1.1 General TI High Voltage Evaluation User Safety Guidelines
        1. 1.1.1.1 Safety and Precautions
  8. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
      1. 2.2.1 GaN Power Stage
      2. 2.2.2 Inductor
      3. 2.2.3 Controller
      4. 2.2.4 Cooling
        1. 2.2.4.1 Heat Sink Placement
        2. 2.2.4.2 Via Placement
        3. 2.2.4.3 Copper Block
    3. 2.3 Highlighted Products
      1. 2.3.1 LMG3100R017
      2. 2.3.2 UCD3138A
      3. 2.3.3 TPSM365R6V5
      4. 2.3.4 TMP61
  9. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Hardware Requirements
    2. 3.2 Software Requirements
    3. 3.3 Test Setup
    4. 3.4 Test Results
  10. 4Design and Documentation Support
    1. 4.1 Design Files
      1. 4.1.1 Schematics
      2. 4.1.2 BOM
      3. 4.1.3 PCB Layout Recommendations
        1. 4.1.3.1 Power Loop Optimization
        2. 4.1.3.2 Return Current Through Output Power Ground
    2. 4.2 Tools and Software
    3. 4.3 Documentation Support
    4. 4.4 Support Resources
    5. 4.5 Trademarks
  11. 5About the Author

2.1 Block Diagram

The reference design uses the LMG3100R017, a small-size GaN field-effect transistor (FET), for a three-phase inverter. The LMG3100R017 integrates the driver and 80V GaN FET in a 6.5mm × 4mm QFN package. This package is optimized for extremely low gate loop and power loop impedance. The PCB offers mounting holes for a heat sink with the top-side cooled LMG3100R017 GaN-FET power modules. An integrated bootstrap diode reduces space for the high-side GaN-FET bias supply.

The control uses the UCD3138A, a digital power supply controller from Texas Instruments. The UCD3138A offers excellent levels of integration and performance in a single-chip solution. The UCD3138A has PMBus communication, which enables easy firmware upgrade and reporting. The design monitors each phase input current through a bidirectional current sense amplifier, the INA241. The 5V auxiliary supply uses an integrated buck module, the TPSM365R6, followed by a low-dropout (LDO) linear regulator to generate a 3.3V rail.

TIDA-050095 System Block DiagramFigure 2-1 System Block Diagram