TIDUF68A February   2024  – March 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 Design Considerations
    3. 2.3 Highlighted Products
      1. 2.3.1 LMG2100
      2. 2.3.2 INA241A
      3. 2.3.3 AMC0106M05
      4. 2.3.4 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
      1. 3.2.1 INA241A Ultra-Precise Current Sense Amplifier with Enhanced PWM Rejection
      2. 3.2.2 AMC0106M05 Precision, ±50mV Input, Functionally Isolated, Delta-Sigma Modulator
    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
      2. 4.4.2 GaN Inverter Half-Bridge Module Switch Node Voltage
        1. 4.4.2.1 Switch Node Voltage Transient Response at 48V DC Bus
          1. 4.4.2.1.1 Output Current at ±1A
          2. 4.4.2.1.2 Output Current at ±10A
        2. 4.4.2.2 Impact of PWM Frequency to DC-Bus Voltage Ripple
        3. 4.4.2.3 Efficiency Measurements
        4. 4.4.2.4 Thermal Analysis
        5. 4.4.2.5 No Load Loss Test (COSS Losses)
      3. 4.4.3 Phase-Current Sensing
  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
  14. 8Revision History

4.4.3 Phase-Current Sensing

A series of tests was performed to quantify measurement noise and the corresponding effective number of bits (ENOB) of the AMC0106M05 at different oversampling ratios. The ENOB was calculated from 1200 consecutive samples measured at the center of the 10kHz PWM over 1200 PWM periods. The PWM vector was kept constant during the test. The constant PWM vector produces constant phase voltage and DC current.

The AMC0106M05 modulator clock input was driven from a C2000™ MCU and the modulator output data bitstream was decimated on a C2000™ MCU through a Sinc3 filter running at oversampling ratios (OSR) from 32 to 256. Figure 4-27 shows the resulting ENOB as a function of OSR.

TIDA-010936 Phase-Current Measurement ENOB vs OSR Figure 4-27 Phase-Current Measurement ENOB vs OSR

For detailed test results on phase-current sensing with the functional isolated modulator AMC0106M05, see the High Resolution, Small Form Factor Phase Current Sense for 48V Robotics and Servo Drives application note.