TIDUFE9 August   2025

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
    1. 1.1 Key System Specifications
    2. 1.2 Electricity Meters
    3. 1.3 Circuit Breakers
    4. 1.4 EV Chargers
    5. 1.5 Protection and Relay
    6. 1.6 Rogowski Coil-Based Current Sensor
      1. 1.6.1 Principle
      2. 1.6.2 Rogowski Coil Types
      3. 1.6.3 Integration Methods
      4. 1.6.4 Rogowski Coil Selection
  8. 2System Overview
    1. 2.1 Block Diagram
      1. 2.1.1 Differential Gain Amplifier
      2. 2.1.2 High-Pass Filter
      3. 2.1.3 Low-Pass Filter
      4. 2.1.4 Active Integrator
    2. 2.2 Design Considerations
      1. 2.2.1 Components Selection
        1. 2.2.1.1 RC Component Selection
        2. 2.2.1.2 RG Selection for Gain Setting
    3. 2.3 Highlighted Products
      1. 2.3.1 INA828
      2. 2.3.2 TLV9001
      3. 2.3.3 LM27762
  9. 3System Design Theory
    1. 3.1 Schematics to Layout
      1. 3.1.1 Rogowski Input Connectors
      2. 3.1.2 Gain Setting Resistor Chain
      3. 3.1.3 Gain Amplifier and High-Pass Filter Stage
      4. 3.1.4 Active Integrator Stage
      5. 3.1.5 Output Stage
      6. 3.1.6 Power Supply
  10. 4Hardware, Testing Requirements, and Test Results
    1. 4.1 Hardware Requirements
    2. 4.2 Test Setup
      1. 4.2.1 Full System Block Diagram
      2. 4.2.2 Test System
      3. 4.2.3 Rogowski Coil
      4. 4.2.4 TIDA-010986
      5. 4.2.5 ADS131M08 Metrology Evaluation Module
      6. 4.2.6 GUI
        1. 4.2.6.1 Getting Started
          1. 4.2.6.1.1 PCB Rogowski Coil Setup
          2. 4.2.6.1.2 TIDA-010986 Connectors
            1. 4.2.6.1.2.1 Input Terminal Block
            2. 4.2.6.1.2.2 Power Connection
            3. 4.2.6.1.2.3 Output Connections
          3. 4.2.6.1.3 ADS131M08 Metrology Evaluation Module Connectors
    3. 4.3 Test Results
      1. 4.3.1 Functional Test
      2. 4.3.2 Accuracy Measurements
        1. 4.3.2.1 No Load Conditions
          1. 4.3.2.1.1 Objective
          2. 4.3.2.1.2 Setup
          3. 4.3.2.1.3 Requirements
          4. 4.3.2.1.4 Results
        2. 4.3.2.2 Initial Load Operation Test
          1. 4.3.2.2.1 Objective
          2. 4.3.2.2.2 Setup
          3. 4.3.2.2.3 Requirements
          4. 4.3.2.2.4 Results
        3. 4.3.2.3 Accuracy Test at Different Load Conditions
          1. 4.3.2.3.1 Objective
          2. 4.3.2.3.2 Setup
          3. 4.3.2.3.3 Requirements
          4. 4.3.2.3.4 Results
        4. 4.3.2.4 Variation of Power Factor Test
          1. 4.3.2.4.1 Objective
          2. 4.3.2.4.2 Setup
          3. 4.3.2.4.3 Requirements
          4. 4.3.2.4.4 Results
        5. 4.3.2.5 Variation of Voltage Test
          1. 4.3.2.5.1 Objective
          2. 4.3.2.5.2 Setup
          3. 4.3.2.5.3 Requirements
          4. 4.3.2.5.4 Results
        6. 4.3.2.6 Variation of Frequency Test
          1. 4.3.2.6.1 Objective
          2. 4.3.2.6.2 Setup
          3. 4.3.2.6.3 Requirements
          4. 4.3.2.6.4 Results
        7. 4.3.2.7 Phase Sequence Reversal Test
          1. 4.3.2.7.1 Objective
          2. 4.3.2.7.2 Setup
          3. 4.3.2.7.3 Requirements
          4. 4.3.2.7.4 Results
  11. 5Design and Documentation Support
    1. 5.1 Design Files
      1. 5.1.1 Schematics
      2. 5.1.2 BOM
      3. 5.1.3 Layout Prints
    2. 5.2 Tools
    3. 5.3 Documentation Support
    4. 5.4 Support Resources
    5.     Trademarks
  12. 6About the Author

3.1.1 Rogowski Input Connectors

Figure 3-1 and Figure 3-2 show the connector where the differential Rogowski coil interfaces with the signal conditioning circuit. A 2-pin terminal (J1) receives the differential output of the coil through inputs INPUT_1_P and INPUT_1_N. To provide signal integrity and avoid undefined behavior when the coil is disconnected. Pulldown resistors at 47.5kΩ (R9 and R10) are placed from each input to ground as suggested in the INA828 50μV Offset, 7nV/√Hz Noise, Low-Power, Precision Instrumentation Amplifier data sheet. These resistors prevent the inputs from floating, which can otherwise lead to noise pickup or erratic behavior in the integrator stage.

TIDA-010986 Terminal Block Input Connection SchematicFigure 3-1 Terminal Block Input Connection Schematic
TIDA-010986 Terminal Block Input ConnectionFigure 3-2 Terminal Block Input Connection