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  • AC and DC Current Fault Detection Reference Design

    • TIDUF03 December   2022

       

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  • AC and DC Current Fault Detection Reference Design
  1.   Description
  2.   Resources
  3.   Features
  4.   Applications
  5.   5
  6. 1System Description
    1. 1.1 Key System Specifications
  7. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 System Design Theory
      1. 2.2.1 Detection Principals
      2. 2.2.2 Saturation
      3. 2.2.3 General Mode of Operation
    3. 2.3 Highlighted Products
      1. 2.3.1 DRV8220
      2. 2.3.2 OPAx202
      3. 2.3.3 TLVx172
      4. 2.3.4 TLV7011
      5. 2.3.5 INA293
      6. 2.3.6 SN74LVC1G74
      7. 2.3.7 TLV767
  8. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Hardware
      1. 3.1.1  Board Overview
      2. 3.1.2  Filter Stage
      3. 3.1.3  Differential to Single-Ended Converter
      4. 3.1.4  Low-Pass Filter
      5. 3.1.5  Full-Wave Rectifier
      6. 3.1.6  DC Offset Circuit
      7. 3.1.7  Auto-Oscillation Circuit
        1.       31
      8. 3.1.8  DRV8220 H-Bridge
      9. 3.1.9  Saturation Detection Circuit
      10. 3.1.10 H-Bridge Controlled by DFF
      11. 3.1.11 MCU Selection
      12. 3.1.12 Move Away From Timer Capture
      13. 3.1.13 Differentiating DC and AC From the Same Signal
      14. 3.1.14 Fluxgate Sensor
    2. 3.2 Software Requirements
      1. 3.2.1 Software Description for Fault Detection
    3. 3.3 Test Setup
      1. 3.3.1 Ground-Fault Simulation
    4. 3.4 Test Results
      1. 3.4.1 Linearity Over Temperature
    5. 3.5 Fault Response Results
  9. 4Design and Documentation Support
    1. 4.1 Design Files
      1. 4.1.1 Schematics
      2. 4.1.2 BOM
    2. 4.2 Documentation Support
    3. 4.3 Support Resources
    4. 4.4 Trademarks
  10. 5About the Author
  11. IMPORTANT NOTICE
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DESIGN GUIDE

AC and DC Current Fault Detection Reference Design

Description

This reference design detects mA-level AC and DC ground fault currents. An auto-oscillation circuit is implemented using a DRV8220 H-bridge that drives the magnetic core in and out of saturation. In addition, an active filter circuit is implemented to identify fault current signal and level.

Resources

TIDA-010237 Design Folder
DRV8220 Product Folder
MSP430F5132, OPA202 Product Folder
INA293, SN74LVC2G74 Product Folder
TLV7011, TLV172 Product Folder
Ask our TI E2E™ support experts

Features

  • Low-cost discrete AC and DC ground fault detection circuit
  • Designed to sense fault current thresholds of 6 mA DC, 30 mARMS AC based off IEC62752 and IEC62955
  • Detection-to-response time < 25 ms (not including relay delay time)
  • Adjustable AC and DC trip thresholds via software
  • Auto-oscillation feedback circuit can drive different magnetic core materials with minimal changes to hardware
  • Active low-pass filter optimized to attenuate auto-oscillation frequency and amplify fault current signal

Applications

  • AC charging (pile) station

 
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