TIDUEM7A
April 2019 – February 2021
Description
Resources
Features
Applications
5
1
System Description
1.1
End Equipment
1.1.1
Electricity Meter
1.2
Key System Specifications
2
System Overview
2.1
Block Diagram
2.2
Highlighted Products
2.2.1
ADS131M04
2.2.2
TPS7A78
2.2.3
MSP432P4111
2.2.4
TPS3840
2.2.5
THVD1500
2.2.6
ISO7731B
2.2.7
TRS3232E
2.2.8
TPS709
2.2.9
ISO7720
2.3
Design Considerations
2.3.1
Design Hardware Implementation
2.3.1.1
TPS7A78 Cap-Drop Supply
2.3.1.2
TPS3840 SVS
2.3.1.3
Analog Inputs
2.3.1.3.1
Voltage Measurement Analog Front End
2.3.1.3.2
Current Measurement Analog Front End
2.3.2
Current-Detection Mode
2.3.2.1
ADS131M04 Current-Detection Procedure
2.3.2.2
Using an MCU to Trigger Current-Detection Mode
2.3.2.2.1
Using a Timer to Trigger Current-Detection Mode Regularly
2.3.2.2.2
MCU Procedure for Entering and Exiting Current-Detection Mode
2.3.2.3
How to Implement Software for Metrology Testing
2.3.2.3.1
Setup
2.3.2.3.1.1
Clock
2.3.2.3.1.2
Port Map
2.3.2.3.1.3
UART Setup for GUI Communication
2.3.2.3.1.4
Real-Time Clock (RTC)
2.3.2.3.1.5
LCD Controller
2.3.2.3.1.6
Direct Memory Access (DMA)
2.3.2.3.1.7
ADC Setup
2.3.2.3.2
Foreground Process
2.3.2.3.2.1
Formulas
2.3.2.3.3
Background Process
2.3.2.3.3.1
per_sample_dsp()
2.3.2.3.3.1.1
Voltage and Current Signals
2.3.2.3.3.1.2
Frequency Measurement and Cycle Tracking
2.3.2.3.3.2
LED Pulse Generation
2.3.2.3.3.3
Phase Compensation
2.4
Hardware, Software, Testing Requirements, and Test Results
2.4.1
Required Hardware and Software
2.4.1.1
Cautions and Warnings
2.4.1.2
Hardware
2.4.1.2.1
Connections to the Test Setup
2.4.1.2.2
Power Supply Options and Jumper Settings
2.4.1.3
Software
2.4.2
Testing and Results
2.4.2.1
Test Setup
2.4.2.1.1
SVS and Cap-Drop Functionality Testing
2.4.2.1.2
Electricity Meter Metrology Accuracy Testing
2.4.2.1.3
Current-Detection Mode Testing
2.4.2.1.4
Viewing Metrology Readings and Calibration
2.4.2.1.4.1
Viewing Results From LCD
2.4.2.1.4.2
Calibrating and Viewing Results From PC
2.4.2.1.4.2.1
Viewing Results
2.4.2.1.4.2.2
Calibration
2.4.2.1.4.2.2.1
Gain Calibration
4.2.1.4.2.2.1.1
Voltage and Current Gain Calibration
4.2.1.4.2.2.1.2
Active Power Gain Calibration
2.4.2.1.4.2.2.2
Offset Calibration
2.4.2.1.4.2.2.3
Phase Calibration
2.4.2.2
Test Results
2.4.2.2.1
SVS and TPS7A78 Functionality Testing Results
2.4.2.2.2
Electricity Meter Metrology Accuracy Results
2.4.2.2.3
Current-Detection Mode Results
3
Design Files
3.1
Schematics
3.2
Bill of Materials
3.3
PCB Layout Recommendations
3.3.1
Layout Prints
3.4
Altium Project
3.5
Gerber Files
3.6
Assembly Drawings
4
Related Documentation
4.1
Trademarks
5
About the Author
6
Revision History
2.3
Design Considerations