TIDUF99 November   2024

 

  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 Design Considerations
    3. 2.3 Highlighted Products
      1. 2.3.1 TMS320F2800137
      2. 2.3.2 LMG2100R026
      3. 2.3.3 TMCS1127
      4. 2.3.4 LM5164
      5. 2.3.5 LM74610-Q1
      6. 2.3.6 AFE031
      7. 2.3.7 CC1352P7
  9. 3System Design Theory
    1. 3.1 MPPT Operation
    2. 3.2 Power Optimizer Function
      1. 3.2.1 Power Line Communication (PLC)
    3. 3.3 Four-Switch Buck-Boost Converter
    4. 3.4 Output Inductance
    5. 3.5 Input Capacitance
    6. 3.6 Current Sensor
      1. 3.6.1 Current Measurement Resolution
      2. 3.6.2 Current Sensor Power Dissipation
    7. 3.7 Switching Regulator
    8. 3.8 Bypass Circuit
  10. 4Hardware, Software, Testing Requirements, and Test Results
    1. 4.1 Hardware Requirements
    2. 4.2 Software Requirements
    3. 4.3 Test Setup
    4. 4.4 Test Results
      1. 4.4.1 Short Mode Test Result
      2. 4.4.2 Switching Mode Test Result
      3. 4.4.3 Bypass Circuit Test Results
      4. 4.4.4 PLC 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

4.4.4 PLC Test Results

Testing the PLC hardware implementation includes validating the coupling circuit and the band-pass filter in the receive path.

To check the coupling circuit, the impedance was measured using a frequency response analyzer (Venable Instruments Model 3120). Importantly, the coupling network needs to present a high impedance at the PLC carrier frequencies and maintains lower impedances outside the communication band. Figure 4-12 shows the measured impedance. Yellow markers highlight the impedance at the mark and space frequencies of the RSD PLC protocol.

TIDA-010949 Impedance Coupling Circuit Figure 4-12 Impedance Coupling Circuit

An additional band-pass filter is implemented in the receive path. In this path it is important that the pass band is set to the carrier frequencies of the PLC communication. Figure 4-13 shows the measured transfer curve of the bandpass filter. The pass band is located between 70kHz and 150kHz. The same frequency response analyzer was used for this measurement.

TIDA-010949 Transfer Curve Band-Pass Filter Receive Path Figure 4-13 Transfer Curve Band-Pass Filter Receive Path

This design verified the PLC coupling circuit and AFE031 with rapid shutdown function in combination with the TIDA-060001 reference design. See also SunSpec Rapid Shutdown Transmit and Receive Reference Design.