Microchip Technology’s MCP3909 energy-measurement IC and the MCP3909 3-Phase Energy Meter Reference Design enable designers to quickly design and develop energy meter designs. The IC combines low power consumption with an SPI interface and active power-pulse output. Supply current for the device is 4 mA.
The IC has two 16-bit delta-sigma onboard ADCs that can be accessed through its SPI interface, while simultaneously providing a pulse output with a frequency proportional to the active-power calculation. This simultaneous output of data makes the IC flexible and easy to use, as well as adaptable to a variety of meter requirements. Additionally, with its 0.1% typical measurement error over a dynamic range ratio of 1000:1, the MCP3909 IC easily fits into meter applications requiring high accuracy.
The MCP3909 3-Phase Energy Meter Reference Design includes three MCP3909 ICs, plus a PIC18F2520 and a PIC18F4550 microcontroller. The PIC18F2520 performs all power calculations in the reference design, while the PIC18F4550 provides a USB interface to desktop software. The software package that comes with the reference design enables meter calibration and the ability to read real and apparent power, as well as rms current and rms voltage.
The MCP3909 is available in a 24-pin SSOP package, priced at $1.51 each in 10,000-unit quantities. The reference design will be available in March at a price of $175 each.
