SLVUDF6 September   2025

 

  1.   1
  2.   Description
  3.   Get Started
  4.   Features
  5.   Applications
  6.   6
  7. 1Evaluation Module Overview
    1. 1.1 Introduction
    2. 1.2 Kit Contents
    3. 1.3 System Description
      1. 1.3.1 Key System Specifications
      2. 1.3.2 End Equipment
      3. 1.3.3 Electricity Meter
    4. 1.4 Device Information
  8. 2Hardware
    1. 2.1 System Overview
      1. 2.1.1 Block Diagram
      2. 2.1.2 Design Considerations
        1. 2.1.2.1 Voltage Measurement - Analog Front End
        2. 2.1.2.2 Current Measurement - Analog Front End
        3. 2.1.2.3 Input Voltage
  9. 3Software
    1. 3.1 Metrology Overview
      1. 3.1.1 Metrology Formulas
      2. 3.1.2 UART for PC GUI Communication
      3. 3.1.3 Direct Memory Access (DMA)
      4. 3.1.4 ADC Setup
      5. 3.1.5 Foreground Process
      6. 3.1.6 Background Process
      7. 3.1.7 Software Function per_sample_dsp ()
      8. 3.1.8 Frequency Measurement and Cycle Tracking
      9. 3.1.9 LED Pulse Generation
  10. 4Implementation Results
    1. 4.1 Evaluation Procedure
      1. 4.1.1 Equipment Setup
      2. 4.1.2 Test Procedure
        1. 4.1.2.1 Working with the Metrology GUI
        2. 4.1.2.2 Calibration
          1. 4.1.2.2.1 Voltage and Current Offset Calibration
          2. 4.1.2.2.2 Voltage and Current Gain Calibration
          3. 4.1.2.2.3 Active Power Gain Calibration
          4. 4.1.2.2.4 Offset Calibration
          5. 4.1.2.2.5 Phase Calibration
    2. 4.2 Performance Data and Results
      1. 4.2.1 Electricity Meter Metrology Accuracy Results
  11. 5Hardware Design Files
    1. 5.1 Schematics
    2. 5.2 PCB Layouts
    3. 5.3 Bill of Materials (BOM)
  12. 6Additional Information
    1. 6.1 Trademarks
  13. 7Compliance Information
    1. 7.1 Compliance and Certifications
  14. 8Related Documentation

2.1.2.2 Current Measurement - Analog Front End

Figure 2-3 shows how the current input analog front end is different from voltage analog front end.

AMC-ADC-1PH-EVM Analog Front End for Current InputFigure 2-3 Analog Front End for Current Input

The analog front end for current consists of footprints for electromagnetic interference filter beads (FB6 and FB8), and a RC low-pass filter (R12, R21, C16, C18).

Equation 2 shows how to calculate the range of differential voltages fed to the current ADC channel for a given maximum current, and shunt resistor value.

Equation 2. VADCSwing,Current,Shunt= ± 2 Rshunt IRMS,max

A SHUNT value of 3mΩ is used, the input signal to the current ADC has a voltage swing of ±63.6mV, 63.6mV when the current rating of the meter (15A) is applied. This relatively low voltage, when using GAIN = 16 is well within the required Full-Scale Range of ±75mV. See also the full-scale range table in the AMC130M02 2-Channel, 64kSPS, Simultaneous-Sampling, 16-Bit, Reinforced Isolated Delta-Sigma ADC With Integrated DC/DC Converter data sheet.

Table 2-1 Full-Scale Range
GAIN SETTINGFSR
1±1.2V
2±600mV
4±300mV
8±150mV
16±75mV
32±37.5mV
64±18.75mV
128±9.375mV