TIDUFG2 December   2025

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
    1. 1.1 Terminology
    2. 1.2 Key System Specifications
  8. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
      1. 2.2.1 Sensor Selection
    3. 2.3 Highlighted Products
      1. 2.3.1 TLV387
      2. 2.3.2 TLV9054
      3. 2.3.3 MSPM0G5187-LP
      4. 2.3.4 LOG300
      5. 2.3.5 UCC28881
      6. 2.3.6 TPS709
  9. 3System Design Theory
    1. 3.1 Current Sensor
    2. 3.2 Hybrid Integrator
    3. 3.3 Band-Pass Filter
      1. 3.3.1 Log Amplifier
      2. 3.3.2 Current Low-Pass Filter
      3. 3.3.3 Non-isolated Voltage Sensing
      4. 3.3.4 Auto Labeling Circuit
        1. 3.3.4.1 Line Voltage Sensing
        2. 3.3.4.2 Arc Gap Voltage Sensing
        3. 3.3.4.3 Differential to Single-Ended Conversion
      5. 3.3.5 Power Supply
  10. 4Hardware, Software, Testing Requirements, and Test Results
    1. 4.1 Hardware Requirements
    2. 4.2 Software
    3. 4.3 Test Setup
      1. 4.3.1 Arc Testing Setup
    4. 4.4 Test Results
  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

3.3.4.1 Line Voltage Sensing

TIDA-010971 Isolated Line Voltage Sensing Schematic Figure 3-12 Isolated Line Voltage Sensing Schematic

Figure 3-12 shows the line voltage sensing circuit. The circuit consists of a resistor divider connected to AMC3330, a reinforced isolated amplifier with a fixed gain of 2.0V/V. The differential output of the AMC3330 connects to the circuit described in Section 3.1.7.3. This differential to single-ended conversion introduces a gain of 1.65V/V. The conversion output then connects to an internal ADC of the MCU.

Equation 3 describes the relation of input voltage between J2 and J3 to output voltage of the differential to single-ended conversion:

Equation 3. V o u t = V i n × 3240 Ω / ( 4 × 316000 Ω + 3240 Ω ) ≅ V i n × 0 . 00256