TIDUF68 February   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
    3. 2.3 Highlighted Products
      1. 2.3.1 LMG2100
      2. 2.3.2 INA241A
      3. 2.3.3 LMR38010
  9. 3System Design Theory
    1. 3.1 Three-Phase GaN Inverter Power Stage
      1. 3.1.1 LMG2100 GaN Half-Bridge Power Stage
    2. 3.2 Inline Shunt Precision-Phase Current Sensing With INA241A
    3. 3.3 Phase Voltage and DC Input Voltage Sensing
    4. 3.4 Power-Stage PCB Temperature Monitor
    5. 3.5 Power Management
      1. 3.5.1 48V to 5V DC/DC Converter
      2. 3.5.2 5V to 3.3V Rail
    6. 3.6 Interface to Host MCU
  10. 4Hardware, Software, Testing Requirements, and Test Results
    1. 4.1 Hardware Requirements
      1. 4.1.1 TIDA-010936 PCB Overview
      2. 4.1.2 TIDA-010936 Jumper Settings
      3. 4.1.3 Interface to C2000™ MCU LaunchPad™ Development Kit
    2. 4.2 Software Requirements
    3. 4.3 Test Setup
    4. 4.4 Test Results
      1. 4.4.1 Power Management and System Power Up and Power Down
    5. 4.5 GaN Inverter Half-Bridge Module Switch Node Voltage
      1. 4.5.1 Switch Node Voltage Transient Response at 48V DC Bus
        1. 4.5.1.1 Output Current at ±1A
        2. 4.5.1.2 Output Current at ±10A
      2. 4.5.2 Impact of PWM Frequency to DC-Bus Voltage Ripple
      3. 4.5.3 Efficiency Measurements
      4. 4.5.4 Thermal Analysis
      5. 4.5.5 No Load Loss Test (COSS Losses)
  11. 5Design and Documentation Support
    1. 5.1 Design Files [Required Topic]
      1. 5.1.1 Schematics
      2. 5.1.2 BOM
      3. 5.1.3 PCB Layout Recommendations
        1. 5.1.3.1 Layout Prints
      4. 5.1.4 Altium Project
      5. 5.1.5 Gerber Files
      6. 5.1.6 Assembly Drawings
    2. 5.2 Tools and Software
    3. 5.3 Documentation Support
    4. 5.4 Support Resources
    5. 5.5 Trademarks
  12. 6About the Author
  13. 7Recognition

2.2 Design Considerations

The design goal was to implement a 3-phase GaN-inverter reference design, which operates from a single DC input voltage from 12V to 60V DC, nominal 48V. A wide input voltage range DC/DC converter LMR38010 generates the 5V rail to supply the GaN-FET power modules and the 3.3V band-gap reference, a 3.3V power modules supplies the current sense amplifiers, input buffer and optional a C2000 MCU LaunchPad development kit.

Each of the three inverter half-bridges employ an integrated 80V, 10A GaN half-bridge module (LMG2100R044) to demonstrate small form factor and high efficiency.

A 1mΩ phase current shunt and a differential current sense amplifier (INA241A) with a gain of 50V / V and a midpoint voltage of 1.65V, set by the 3.3V reference (VREF3333) allows a full-scale current range of ±33A. A thermistor (TP61) monitors the PCB temperature close to the GaN power module.

A high-side DC-link current sense comparator allows hardware-based short-circuit protection, DC-link and phase voltages are also measured and allows validation of advanced sensorless designs like InstaSPIN-FOC™.

The design offers a TI BoosterPack compatible 3.3V I/O interface with to connect to a C2000™ MCU LaunchPad™ development kit or Sitara™ microcontrollers for quick and easy performance evaluation of our GaN technology.