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

3.6 Interface to Host MCU

GUID-20240220-SS0I-7G5T-Q5LN-C1X5PSB09MFG-low.svg Figure 3-11 Schematic of Host Interface Connectors J1 and J2

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 A, B, and C; 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 R57 (20Ω) and C58 (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-010936 fits only upper headers of an 80-pin C2000 MCU LaunchPad, like the LAUNCHXL-F28P65X. Additionally, the TIDA-010936 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. The details of the pin assignment are outlined in Section 1.1 in Table 1-2 and Table 1-3, respectively.