Renesas Electronics has introduced its new microcontrollers (MCUs) for the power meter market, particularly targeting smart meters. The new RL78/I1C Group of MCUs is designed for the international standard DLMS1 with enhanced security functionality and improved arithmetic operation.

Demand for electric power has increased worldwide in recent years, and the adoption of smart meters has spread rapidly in order to encourage energy conservation, support the liberalisation of the power industry, and prevent electricity theft. The number of installations per year of smart meters with enhanced security features such as DLMS support is expected to grow from 30 million in 2016 to 110 million in 2020 worldwide2. Ensuring the security of power meter data and lowering meter prices have become key issues amidst this sudden increase in the number of smart meters in use. As a result, power meter manufacturers are calling for improved security features to support DLMS and reduced development cost by utilising common platform for various meter systems. To address these key needs, Renesas developed the RL78/I1C MCUs for smart meters with DLMS support, leveraging key features from the current RL78/I1B Group of MCUs, such as industry-leading low power consumption and numerous on-chip peripheral functions for reduced system cost.

Smart meters require authentication and encryption/decryption functions that conform to the DLMS standard when transferring power meter data measured using a power-measurement MCU to the communication block. The RL78/I1C integrates an AES hardware engine for this purpose. In particular, the RL78/I1C is the power meter field industry’s first to implement in hardware the AES GCM mode required by the DLMS standard, and thereby delivers a speed boost of 20 times or more5 compared with encryption and decryption using software processing on existing Renesas MCUs.

In addition, the on-chip phase-locked loop (PLL) boosts the maximum operating frequency from 24MHz to 32 MHz, and the 32-bit multiplier/multiply-and-accumulate unit dramatically reduces the load imposed by software power calculation with 24-bit data converted by the 24-bit ΔΣs A/D converter, resulting in an approximate 30-percent increase in arithmetic operation capacity. This means that a single chip can handle both electric power measurement processing and DLMS processing. The RL78/I1C MCUs can perform processing to support DLMS communication while simultaneously processing electric power measurement. Up to 256KB of on-chip ROM can accommodate program code for both electric power measurement processing and DLMS processing. This leads to approximately 30% reduced power consumption compared to a two-chip configuration and reduced system cost compared with earlier two-chip solutions comprised of power measurement and dedicated DLMS processing MCUs.

The new RL78/I1C MCUs are available in seven versions, with on-chip memory capacities ranging from 64KB for low-end single-phase meters, 128KB for high-end single-phase meters, and 256KB for three-phase meters; and package pin counts from 64 pins for space-saving needs, 80 pins for single-phase meters aimed for use in emerging countries, to 100 pins for single-phase meters aimed for use in advanced applications.

Samples of the RL78/I1C are available now. Mass production is scheduled to begin in August 2016 and is expected to reach a volume of 200,000 units per month by September 2017. Availability is subject to change without notice.