This reference design aids in optimizing circuit performance, ensuring precision, and enabling innovative features like real-time data analytics and remote monitoring.
A single-phase shunt energy meter reference design is a crucial tool in modern energy management systems, providing accurate measurement and monitoring of electrical energy consumption. Its importance lies in its ability to enhance efficiency, reduce costs, and support sustainability efforts. Applications range from residential and industrial energy metering to smart grids and IoT-enabled devices. For design engineers, it simplifies the development process by offering a pre-validated platform, reducing time-to-market and ensuring compliance with industry standards.
The increasing accuracy requirements and processing demands of modern electricity meters have made it challenging to rely solely on a single metrology system-on-chip (SoC). A dual-chip architecture, combining a standalone ADC and a host microcontroller (MCU), provides an effective solution by overcoming these limitations and enabling flexible, market-specific designs. This reference design TIDA-010940 by Texas Instruments (TI) leverages a high-accuracy standalone ADC, such as the ADS131M03, paired with an ultra-low-power MSPM0L2228 MCU, creating a cost-efficient platform for single-phase electricity meters.
The ADS131M03 is a three-channel, 24-bit delta-sigma ADC that achieves 0.5S accuracy using a shunt current sensor. Its simultaneous-sampling capability ensures precise measurements while maintaining cost efficiency. The MSPM0L2228 MCU supports segmented LCDs with up to 8×51 or 4×55 customizable COM and SEG lines, enabling compact and efficient PCB layouts. Additionally, its VBAT power domain includes essential features such as a real-time clock, tamper detection, time-stamping, and backup memory, ensuring reliability and functionality during power outages. The MCU also facilitates communication with support for external SPI FLASH memory and dual UART interfaces, including an IrDA optical port (EN 62056-21) and an isolated RS-485 connection. The RS-485 interface employs capacitive galvanic isolation, ensuring durability and an extended lifespan, which is crucial for industrial applications.
This reference design’s firmware processes data from the ADC in real time to calculate critical metrology parameters such as active, reactive, and apparent energy, RMS voltage/current, power factor, and line frequency. These metrics can be visualized through a calibration GUI or pulsed outputs, seamlessly integrating with metrology test systems. The design achieves class 0.5S accuracy across a 25mA–100A input range with an 8kHz sampling rate. Magnetic tamper detection is enabled by the DRV5032 Hall-effect sensor, enhancing security against tampering attempts.
Additional features include robust energy metrology software integrated into the MSPM0-SDK Version 2.02.00.05, compatible with TI Code Composer Studio, and a 5kVRMS isolated RS-485 interface for industrial-grade durability. By addressing the demands for precision, reliability, and cost optimization, this design offers a scalable and advanced solution for single-phase electricity meters in diverse global markets.
TI has tested this reference design. It comes with a bill of materials (BOM), schematics, assembly drawing, printed circuit board (PCB) layout, and more. The company’s website has additional data about the reference design. To read more about this reference design, click here.
