Renesas Electronics Corporation (TSE: 6723), a premier supplier of advanced semiconductor solutions, today announced the availability of 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 DLMS (Note 1) with enhanced security function and improved arithmetic operation. The RL78/I1C Group of MCUs also retains the measurement accuracy and low power consumption of its predecessor, the RL78/I1B Group, of which more than 30 million units have been shipped over a period of three years.
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 liberalization 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 worldwide (Note 2). 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 utilizing 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.
The new RL78/I1C MCUs are available in seven versions, with on-chip memory capacities ranging from 64 kilobytes (KB) for low-end single-phase meters, 128 KB for high-end single-phase meters, and 256 KB 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.
Key features of the RL78/I1C Group of MCUs:
(1) Ability to implement electric power measurement processing and DLMS processing on a single chip, reducing power consumption by 30 percent compared to a two-chip configuration
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 (Note 3) 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 (Note 4) mode required by the DLMS standard (Note 2), thereby delivers a speed boost of 20 times or more (Note 5) 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 24 megahertz (MHz) 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 256 KB of on-chip ROM can accommodate program code for both electric power measurement processing and DLMS processing. This leads to approximately 30 percent 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.
(2) Support for three-phase, four-wire meters, enabling support for new products ranging from single-phase to three-phase
The event link controller (Note 6) function and phase adjustment function coordinate the operation of the four-channel 24-bit ΔΣ A/D converter and three-channel 10-bit Successive Approximation Register (SAR) A/D converter. This enables current and voltage measurement on seven channels, as required in three-phase, four-wire meters. The addition of support for three-phase, four-wire meters, in addition to conventional single-phase, two-wire and three-phase, three-wire meters, allows meter manufacturers to utilize the RL78/I1C as a common platform to develop various meters from industrial to consumer.
In addition, Renesas has extended the features and functionality of the existing RL78/I1B to the new MCUs, along with improvements to the real-time clock that achieves a standby mode current consumption of 0.7μA (Typ.) during operation with independent power supply and power monitoring function with battery backup function that enable the CPU and peripheral functions to continue operating even when a power outage occurs.
(3) Meter analog evaluation kit and meter reference kit that help reduce development time by approximately 25 percent and reduce development cost
Demand for power meters is growing rapidly in worldwide markets, especially emerging economies. This calls for quicker time to development for new meter models and utilizing the current expertise more efficiently. By using the meter analog evaluation kit in the initial study phase, it is possible to start evaluating performance characteristics of the RL78/I1C without actually writing programs. The meter reference kit, which includes hardware and drivers for measurement functions as well as a highly reliable DLMS library, can be used in the meter development phase to reduce the time required for development by approximately 25 percent, compared with independent development, and also to reduce costs.