Utility companies now rely on electronic meter technology to improve grid performance and reliability, as well as reduce costs and offer energy-saving consumer options. The Texas Instruments MSP430FE42x2 microcontroller (MCU) series reduces the electronic bill of materials (BOM) to the $1 range in high volumes for single-phase electricity metering (e-metering) applications.
These MCUs integrate all metering functionality onto a single chip while offering ultra-low-power operation so only simple voltage regulation such as that provided by TI’s TPS78230 regulator is required for a complete solution. The devices in the series come in a 64-pin low-profile quad flat package (LQFP). They also offer up to 32 kbytes of in-system programmable flash memory.
A unique embedded signal processor (ESP) peripheral fully automates energy conversion by integrating two independent, high-resolution sigma-delta analog-to-digital converters (ADCs), programmable gain amplifiers, a temperature sensor, precision voltage reference, H/W multiplier, and a dedicated fixed-function MSP430 CPU. The ESP also provides 0.1% accurate energy measurement over a dynamic current range of 1000 to 1, surpassing the 1% accuracy common in typical meters today, TI says.
A second fully programmable on-chip MSP430 CPU is available for application processing and communication functions. An enhanced watchdog timer, brownout protection, and a supply voltage supervisor increase system reliability. A 128-segment LCD driver, a three-channel 16-bit pulse-width modulation timer, serial communication port, and a basic timer for a real-time clock function provide all functionality for a complete meter implementation while saving board space.
The MCUs also offer direct device operation from a 3-V supply with the CPU and ESP active at only 2.5 mA. During a power outage, the MSP430FE42x2 can operate in standby mode at 1.1 µA with real-time clock function active. Ultra-low power can enable 10- and 20-year battery life in metering applications.
Available today, the MSP430FE42x2 MCUs are fully compatible with the $149 MSP-FET430U64 JTAG emulation toolkit, speeding development and time-to-market, according to TI.
Texas Instruments
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