Maxim's MAXQ3180 Energy-Measurement IC Provides the Most Features at the Lowest Power

Market Wire, June, 2008

Maxim Integrated Products (PINKSHEETS: MXIM) introduces the MAXQ3180, a highly accurate and low-power polyphase IC for measuring electricity activity.

Synopsis for Investor:
--  The MAXQ3180 is an energy-measurement IC for electricity meters.

--  The many features of the MAXQ3180 anticipate emerging industry demands,
    so the device provides the utmost design flexibility, saves design
    time, and shortens time to market.

--  The device integrates precision analog and innovative signal-processing
    techniques to provide more advanced metering features than any single
    product in the market today.

Electricity metering challenge: evolving features and time to market

The industry requirements for electricity metering are evolving rapidly and becoming more challenging for both the meter design companies and the providers of electricity metering equipment. Compounding the need for high accuracy at the lowest possible cost is the dynamic nature of the electricity market itself. New monitoring metrics frequently emerge, and are then requested by the utility companies. Recent examples include power theft detection, real-time power quality monitoring, and consumption pattern reporting (i.e., load profiling). These new metrics often translate into new metering device functions, enhanced capabilities, and complex communication protocols.

Inevitably implementing new device performance capabilities with rigorous performance expectations takes time to design and implement in a new metrological device. Time to market is, of course, critical for both the meter utility companies and the solution providers. It is thus imperative that new metering designs integrate enough capabilities to accommodate emerging industry demands. The metering devices must also provide the utmost flexibility to save design time.

The MAXQ3180s integrates the capabilities demanded for today's most advanced energy-measurement IC. It provides reactive and power-factor measurements for which some utilities may bill. It delivers the critical ampere-hour measurements, plus peak current and voltage measurements. The device gives instantaneous power for peak demand calculations. The complex communication protocols are managed by a host microcontroller through a standard SPI interface.

The MAXQ3180 integrates more metering features than any single competitive device. It meets the demanding performance specifications of today's electricity metering industry while operating at the lowest power. See a comparison table of these metering features at www.maxim-ic.com/MAXQ3180-Table1

Electricity metering challenge: high accuracy and cost sensitivity

The electric utility and the energy consumer want accurate metering, and often across a very wide dynamic range. With huge amounts of power measured constantly, each KWH that is monitored inaccurately represents significant money to the power companies or to the consumers.

Some numbers illustrate the challenges that electricity metering poses for the utilities and device designers. Four specifications are worth noting.

1. A typical class 1 meter may specify a measurement range of 1,000:1. (That is, the power flow must be measured accurately with the current input changing over a 1,000 to 1 range.)

2. The maximum error specification for the metrological device is typically 0.1% of the parameter being measured over the specified dynamic range.

3. Assuming that the ADC full scale is 1V, the smallest signal that must be measured would be 1mV. Therefore, with a target error of 0.1% of 1mV, the smallest signal to measure is 1microvolt. To resolve 1microvolt out of 1V, one would need a 20-bit ADC.

One should now ask, why have the above measurement specifications been so difficult to achieve with traditional electricity metering devices? What do these specifications and performance expectations mean for the designer of electricity metering devices? The answer starts with the ADC.

ADCs with 20-bit or better accuracies do exist, but they are not cost-competitive for the mass market of energy meters. Consequently, the provider of electricity metering devices must deliver a more economical, cost-competitive solution that contains not only adequate ADCs but also the best signal-processing chain so that the target energy error is achieved. The MAXQ3180 integrates an 8-channel ADC and dynamic gain control that resolves the 1microvolt from 1V demanded by the industry.

4. The metering environment is often noisy and subject to high-voltage spikes. The minimum EFT (electric fast transient) specification for the meter is 4kV.

This latter performance specification is equally challenging for electricity meter designers. Circuit boards must withstand the abuse of the deployment environment and yet maintain adequate fidelity to the very small analog input signals.

New electricity meter provides the most metering features at the lowest power

The MAXQ3180 integrates an 8-channel analog-to-digital converter (ADC) and a dedicated, high-performance MAXQ ® microprocessor for computing a broad set of poly-phase multifunction energy metering parameters. Six of the input channels are dedicated to the three phase voltages and three currents. One channel is dedicated for the neutral line current monitoring, and the 8th channel is for on-chip temperature monitoring. With this high integration, the MAXQ3180 makes it easy to monitor the power grid and load status.