TIDUFK2 September   2026

 

  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 Processing
      2. 2.2.2 Voltage and Current Sensing
        1. 2.2.2.1 Voltage Measurement
        2. 2.2.2.2 Current Measurement
      3. 2.2.3 Solenoid – Relay Driver
      4. 2.2.4 Temperature Measurement
    3. 2.3 Highlighted Products
      1. 2.3.1 CC2340R53
      2. 2.3.2 OPA2323
      3. 2.3.3 DRV8213
      4. 2.3.4 TMP236A2
  9. 3System Design Theory
    1. 3.1 Software Architecture
      1. 3.1.1 System Initialization
      2. 3.1.2 Sample Acquisition
      3. 3.1.3 Sample Processing and Task Prioritization
    2. 3.2 Circuit Breaker Functionality
      1. 3.2.1 Breaker State and Relay Control
      2. 3.2.2 Instantaneous Short-Circuit Trip
      3. 3.2.3 Inverse-Time Overload Trip
    3. 3.3 Electrical Metrology
    4. 3.4 Zigbee Connectivity
  10. 4Hardware, Software, Testing Requirements, and Test Results
    1. 4.1 Hardware Requirements
      1. 4.1.1 Hardware Connections and Test Points
    2. 4.2 Test Setup
      1. 4.2.1 Connecting the TIDA-011030 to the Metering Test Equipment
      2. 4.2.2 Power-Supply Options
      3. 4.2.3 Metrology Calibration
      4. 4.2.4 Test-Data Acquisition and Error Calculation
    3. 4.3 Test Results
      1. 4.3.1 Relay Control and Protection
        1. 4.3.1.1 Relay Pull-In and Holding PWM
        2. 4.3.1.2 Instantaneous Trip and Relay-Opening Latency
        3. 4.3.1.3 Inverse-Time Overload Trip
      2. 4.3.2 Metering
      3. 4.3.3 Real-Time Software Performance
      4. 4.3.4 Zigbee Functional Test
  11. 5Design and Documentation Support
    1. 5.1 Tools and Software
      1. 5.1.1 Tools
      2. 5.1.2 Software
    2. 5.2 Documentation Support
    3.     Trademarks
  12. 6About the Author

3.2 Circuit Breaker Functionality

The circuit-breaker subsystem controls the relay and provides local protection against short-circuit and overload conditions. All protection decisions are made directly on the CC2340R53 and do not depend on the Zigbee connection or an external home automation system.

The breaker starts in the hardware-safe open state and can be opened or closed using the local push button or a Zigbee command. Protection events always take priority over user commands. The stored trip reason identifies which protection path caused the disconnection.

The following functions are implemented:

  • Sample-based instantaneous overcurrent trip
  • Hardware-assisted ADC window-comparator trip
  • Inverse-time overload protection with heating and cooling behavior
  • Zigbee reporting of breaker state, service-disconnect status, and trip reason
  • Zigbee overcurrent warning with hysteresis

The Zigbee overcurrent warning is asserted when the measured RMS current reaches the nominal breaker rating and is released when the current falls below 95% of that value. This warning does not itself open the breaker. This indicates that the nominal current has been exceeded while the inverse-time overload protection continues to evaluate the duration and magnitude of the overload.

The current firmware does not implement overtemperature or overvoltage and undervoltage protection. Temperature and line voltage are already measured and reported, allowing these protection functions to be added later without changing the analog measurement hardware. Relay-coil current is also sampled, but automatic relay fault diagnostics are not yet implemented.

The implemented protection behavior is designed around the Type B requirements of EN 60898-1. Final trip thresholds, timing, relay opening time, and thermal behavior must nevertheless be validated on the completed hardware using calibrated test equipment.