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

3.6 Phase Voltage and DC Input Voltage Sensing

The phase voltage for each phase and the DC link voltage, which is equal to the input voltage, are sensed through a resistor divider. Figure 3-6 shows an example of this for the DC-Link voltage (R48, R52) with a low-pass filter (C107) to attenuate the PWM carrier frequency. The phase voltage is scaled to 3.3V, assuming an absolute maximum voltage of 80V.

TIDA-010276 TIDA-010276 Phase Voltage and DC Input Voltage Sensing Figure 3-6 TIDA-010276 Phase Voltage and DC Input Voltage Sensing