New smart-meter chips from STMicroelectronics (Geneva) are said to enable utility companies to improve billing by measuring accurately down to extremely low power levels. The STPM3 devices prevent such losses by keeping the meter accuracy down to just a few milliamps, comparable to the current drawn by an LED television in standby. The chips also enable the development of more economical meters that help utilities reduce their operating costs. By performing power-quality calculations on-chip, including RMS voltage and current measurement, apparent-energy computation, and under-voltage/over-voltage detection, the chips can offload the meter’s host processor thus simplifying software, according to the company. Neutral-phase tamper detection in the STPM33 and STPM34 helps further simplify the design and enhance system security. The STPM32, STPM33 and STPM34 devices integrate key functions that simplify hardware design, saving external components and pc-board size. These include:
- A voltage regulator
- A temperature-compensated voltage reference supporting long-term accuracy
- A SPI/UART host connection allowing low-cost isolation for immunity to DC magnetic fields.
For more information, visit www.st.com