Worldwide, electrical utility metering is undergoing dramatic changes. To
deal this variety of applications, Microchip has introduced two chips and an
online design center to help engineers create metering products. The company's
standalone analog front-end/data-converter MCP3905 and MCP3906 energy-measurement
ICs output average and instantaneous real power data.
These devices can be paired with Microchip's PIC microcontroller in products for single-phase energy measurement in residential power meters and industrial applications. They meet or exceed the requirements of the International Electrotechnical Commission IEC62053 international energy-metering specification.
Both chips integrate a pair of 16-bit delta-sigma analog-to-digital converters, an internal voltage reference, and all of the digital circuitry needed to calculate average and instantaneous real power from voltage and current channels. The MCP3905 has a programmable gain amplifier with a maximum gain of 16. Maximum gain in the MCP3906 is 32 for energy meters requiring higher accuracy.
Microchip's online design center offers charts describing what's needed to create a utility metering design. The "Introduction to Metering" explains the migration from mechanical meter designs to electronic-based solutions. The site also provides metering application notes, reference designs, and other technical documentation.
In 10,000-unit lots, the MCP3905 is $1.58 and the MCP3906 is $1.85. Both come in 24-pin shrink small-outline packages. The Energy Meter Reference Design Board costs $45, and the Evaluation Board costs $75.
Microchip
www.microchip.com