TIDUF86A January   2025  – July 2025

 

  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 System Overview
    3. 2.3 Highlighted Products
      1. 2.3.1 LMG3100
      2. 2.3.2 LMR38010
      3. 2.3.3 TMP61
      4. 2.3.4 TPS7B81
      5. 2.3.5 OPA4323
  9. 3System Design Theory
    1. 3.1 Power Stage Design: Three-Phase Inverter
    2. 3.2 LMG3100 GaN-FET Power Stage
    3. 3.3 Power Management
    4. 3.4 Current-Sensing Circuit
    5. 3.5 Overcurrent Protection Circuit
    6. 3.6 Phase Voltage and DC Input Voltage Sensing
    7. 3.7 Power-Stage PCB Temperature Monitor
    8. 3.8 Interface to Host MCU
  10. 4Hardware, Testing Requirements, and Test Results
    1. 4.1 Hardware Requirements
      1. 4.1.1 TIDA-010276 PCB Overview
      2. 4.1.2 TIDA-010276 Jumper Settings
    2. 4.2 Test Setup
    3. 4.3 Test Results
      1. 4.3.1 Power Management and System Power Up and Power Down
      2. 4.3.2 GaN Inverter Switch Node Voltage
      3. 4.3.3 Switch Node Voltage Transient Response
      4. 4.3.4 Impact of PWM Frequency to DC-Bus Voltage Ripple
      5. 4.3.5 Efficiency Measurements
      6. 4.3.6 Thermal Analysis
  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
    4. 5.4 Support Resources
    5. 5.5 Trademarks
  12. 6About the Author
  13. 7Revision History

3.8 Interface to Host MCU

The interface-to-host processor, such as the C2000 MCU, is compliant to a 3.3V I/O and provides all the required signals like the complementary PWM signals for phase U, V, and W; a PWM trip and disable signal; as well as accurate phase current, phase voltage, and DC-link voltage feedback to control the three-phase GaN inverter. The analog PCB temperature feedback (temp) further helps to protect the three-phase GaN power stage and adjust the safe operating area (SOA). Each analog feedback signal is low-pass filtered with an RC filter, for example R90 (20Ω) and C125 (2.2nF) before connecting to the MCU-integrated ADC. The 2.2nF capacitor is placed to drive the switched input capacitors of the ADC, which are typically in the range of 5pF to 15pF. The Schottky diodes D2 through D6 clamp the maximum phase voltages to around 3.6V in case the DC bus voltage exceeds the 80V (absolute maximum) value. The TIDA-010276 fits only upper headers of an 80-pin C2000 MCU LaunchPad, like the LAUNCHXL-F2800137. Additionally, the TIDA-010276 host interface offers the option to provide the 3.3V rail to power the C2000 LaunchPad. This option provides proper power-up sequencing of the entire system.


TIDA-010276 TIDA-010276 Interface

Figure 3-8 TIDA-010276 Interface