One-Phase Shunt Power Meter Reference Design

Design single-phase energy meters with this reference design—achieve precision, flexibility, and efficiency for modern energy solutions.

TIDA-010960 is a reference design from Texas Instruments (TI) that provides design engineers with a comprehensive solution for developing a single-phase energy meter using isolated multichannel ADCs. This design uses the AMC130M02 isolated ADC to sample a shunt current sensor, offering 0.5% accuracy across a 50mA–15A range with a 4kHz sampling rate. The metrology parameters are calculated by the TI Arm Cortex-M0+ microcontroller, enabling precise energy measurement. The reference design is suitable for a range of applications, including electricity meters, major appliances, small home appliances, heat pumps, and lighting systems in single-phase configurations.

As industries transition to clean, net-zero electricity systems, this reference design helps engineers create smart and flexible grids that empower consumers to manage their energy usage more effectively. By utilizing this design, engineers can develop systems that allow consumers to shift electricity consumption to cheaper, off-peak periods, such as heating HVAC heat pumps during low-cost electricity hours. This contributes to reduced energy costs and more efficient energy use in homes and small businesses.

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This electricity meter provides several key benefits, such as detecting electricity usage, calculating the power consumption of end equipment, and displaying this data for consumers. The built-in real-time clock (RTC) function allows the meter to automatically adjust the heating or charging of equipment during the cheapest electricity periods. It also functions as a power monitor, alerting consumers if the equipment is not functioning properly.

Engineers working with this reference design can choose between single-phase or multiphase configurations, depending on the end equipment’s requirements. The design incorporates an isolated single-phase setup using the AMC130M02 ADC, providing power and data isolation. It meets stringent accuracy requirements, fulfills minimum sample rate needs without compromising performance, and offers flexibility in selecting the host MCU. This flexibility includes choosing based on processing capabilities, RAM, flash capacity, and communication modules such as SPI, UART, I2C, RTC, and CRC.

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The reference design uses two channels of the isolated AMC130M02 ADC and the cost-effective MSPM0G1106 MCU, with one channel for current sensing through a shunt resistor and the other for voltage sensing. The firmware supports metrology calculations for single-phase energy measurement, including key parameters like phase active energy, reactive energy, apparent energy, and other critical power measurements.

For voltage sensing, the design ensures that the Mains voltage is scaled appropriately to fit the input range of the AMC130M02 device by choosing suitable voltage divider resistors. This approach minimizes the voltage-to-current crosstalk, improving metrology accuracy while slightly reducing voltage accuracy, which is less critical in this application.

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.