Renesas Electronics introduces the RL78/I1C series of microcontrollers that support the International Standard for Smart Meters (DLMS)

Renesas Electronics, Inc., a leading global supplier of semiconductor solutions, has announced the launch of a new microcontroller (MCU) for the electricity meter market, particularly the smart meter market. The new RL78/I1C series MCU is designed to meet the requirements of the international standard DLMS with enhanced safety features and improved arithmetic speed. In addition, the RL78/I1C series MCUS retain the measurement accuracy and low power consumption characteristics of the previous generation, the RL78/I1B series. Over the past three years, the RL78/I1B series has sold 30 million units.

In recent years, the demand for electricity has increased worldwide, and the use of smart meters has expanded rapidly to encourage energy conservation, support the opening up of the power sector and prevent electricity theft. The number of DLMS compliant smart meters with enhanced security features installed annually worldwide is expected to increase from 30 million in 2016 to 110 million in 2020 (Note 2). Ensuring the security of meter data and reducing meter prices have become the key factors for the rapid increase in the use of smart meters. Therefore, meter manufacturers are working hard to improve product safety features to support DLMS standards, and use a common platform to develop different meter systems to reduce development costs.

To meet these critical needs, Renesas has developed the RL78/I1C series of smart meter MCUS that support DLMS and take advantage of key features of the current RL78/I1B series of MCUS, such as industry-leading low power consumption and multiple on-chip peripherals that can be used to reduce system costs.

The RL78/I1C series of new MCUS is available in seven versions with on-chip storage capacities including: 64KB(for low-end single-phase meters), 128KB (for high-end single-phase meters) and 256KB (for three-phase meters); The number of packaged pins includes: 64 pins (for space saving needs), 80 pins (for single-phase meters used in emerging countries), and 100 pins (for single-phase meters designed for advanced applications).

Key features of RL78/I1C Microcontroller (MCU) :

(1) Electrical power measurement processing and DLMS processing can be performed on a single chip, and the power consumption is reduced by 30% compared with the two-chip configuration

When transmitting the meter data from the power measurement MCU to the communication module, the smart meter needs to have DLMS compliant authentication and encryption/decryption capabilities. For this purpose, the RL78/I1C microcontroller integrates an AES(Note 3) hardware engine. In particular, the RL78/I1C is the first microcontroller in the meter industry to implement in hardware the AES GCM encryption (Note 4) mode required by the DLMS standard (Note 2), providing a 20x or greater speed improvement compared to software-processed encryption and decryption technology on existing Renesas MCUS (Note 5).

In addition, the on-chip phase-locked loop (PLL) increases the maximum operating frequency from 24MHz to 32MHz, and the 32-bit multiplier/multiplier accumulator significantly reduces the load imposed when calculating software power with 24-bit data converted by 24-bit ΔΣs analog-to-digital converters, thereby increasing arithmetic power by approximately 30%. This means that electrical power measurement processing and DLMS processing can be performed simultaneously using a single chip. The RL78/I1C MCU can handle electrical power measurement while performing processing to support DLMS communication. Up to 256KB of on-chip ROM can store program code for power measurement processing and DLMS processing. It can reduce power consumption by approximately 30% compared to a dual-chip configuration. It reduces system costs compared to earlier two-chip solutions consisting of power measurement and dedicated DLMS processing MCUS.

(2) Support three-phase four-wire meters, thereby supporting new products from single phase to three phase

The event Link controller (Note 6) function and phase modulation function can be used with a four-channel 24-bit ΔΣ analog-to-digital converter and a three-channel 10-bit Successive approximation register (SAR) analog-to-digital converter. In this way, seven-channel current and voltage measurement can be carried out according to the requirements of three-phase four-wire meters. In addition to traditional single-phase two-wire and three-phase three-wire meters, the addition of support for three-phase four-wire meters allows meter manufacturers to use the RL78/I1C as a common platform to develop a variety of industrial and residential meters.

In addition, Renesas has extended the functions and features of the existing RL78/I1B into the new MCU, while improving the real-time clock to achieve current consumption of 0.7μA(typical) in standby mode during operation using a separate power supply and power monitoring function. The operating module is equipped with a backup battery so that CPU and peripheral functions can continue to work even in the case of power failure.

(3)The meter Simulation Evaluation Kit and meter reference Kit help reduce development time by approximately 25% and reduce development costs

Demand for electric meters is increasing rapidly in the global market, especially in emerging markets. This calls for faster development of new meters and more efficient use of current expertise. By using the meter Simulation evaluation Kit during the initial study phase, the performance characteristics of the RL78/I1C can be evaluated without actually writing a program. The meter reference kit includes hardware and drivers for the measurement function as well as a highly reliable DLMS library. It can be used in the meter development phase to reduce development time by about 25%(compared to independent development) and also reduce costs.