May 19, 2014, Seoul – STMicroelectronics (ST), a global semiconductor company contributing to customers across various electronic applications, has launched new smart meter chips STPM32, STPM33, and STPM34.

Recently, home appliances have been trending toward unprecedentedly low standby power consumption. With the newly released smart meter chip, public utilities can accurately measure power usage even at extremely low power levels, which will help improve billing.

Meters equipped with ST’s latest STPM32, STPM33, and STPM34 chips minimize revenue loss for public utilities and ensure consistent billing even with very frugal usage. While existing meters are capable of accurate measurements down to low current levels of about 50mA, in today’s era of low standby power, errors at lower current levels can result in billing losses of several megawatt-hours (MWh) for large-scale users. The STPM3 chip prevents such losses by maintaining metering accuracy down to the milliamp level. This level is comparable to the current consumed by an LED TV in standby mode.

Furthermore, ST’s latest chips enable the development of more economical meters, helping to reduce operating costs for public utilities. Since power quality calculations—including RMS voltage and current measurement, apparent energy calculation, and undervoltage/overvoltage detection—are performed on-chip, the load on the meter’s host processor is reduced, allowing for software simplification. STPM33 and STPM34 are equipped with a neutral-phase tamper detection function, which can further simplify system safety design or improvement. In the case of STPM34, apparent power of single-phase and multi-phase systems can also be calculated.

The STPM3 chip incorporates key features that simplify hardware design, contributing to a reduction in the number of external components and PC board size. These features include a voltage regulator, a temperature-compensated voltage reference supporting long-term accuracy, and SPI/UART host connectivity that enables low-cost isolation for DC magnetic field immunity. True single-point calibration simplifies meter manufacturing and reduces field service overhead costs. This new product is capable of measuring frequencies down to DC, and its wide DC bandwidth allows for accurate measurement of harmonic content, aiding in power quality assessment.

STPM32, STPM33, and STPM34 provide two, three, and four independent channels, respectively, for single-phase and poly-phase AC applications. They comply with applicable standards of the International Electrotechnical Commission (IEC) and the American National Standards Institute and meet the requirements of the State Grid Corp of China.