A three-phase power meter needs to deal with more current and voltage information compared to a single-phase power meter and requires analog input for a maximum of seven channels and high processing capacity for power calculation. Further, the smart power meter needs to meet the security requirements of the DLMS international standard and so on.
Renesas offers microcontrollers for three-phase power meters equipped with optimum analog input structure and calculation support functions.

The 32-bit CPU RX21A microcontroller is equipped with an up to 7-channel 24-bit ΔΣA/D converter, AES encryption engine, and 1.56 DMIPS/MHz processing performance suitable for high-end three-phase power meters.

The 16-bit CPU RL78/I1C microcontroller is equipped with an up to 4-channel 24-bit ΔΣA/D converter, a phase adjustment function, a high pass filter, and also a 32-bit multiply-accumulator, making it suitable for low-end three-phase power meters. In addition, it is equipped with an encryption/decryption processing hardware engine which supports AES encryption GCM mode to support DLMS standard security requirements.
The three-phase 4-wire power meter can be supported by linking a 4-channel ΔΣA/D converter and a 3-channel sequential A/D converter with the event link controller.

Power Meter (Three-Phase)

System Block Diagram

System Block Diagram (Main control block: MCU with embedded ΔΣADC)

Recommended Products
Block Semiconductor device Recommended products Features, etc.
Control MCU RL78/I1C Group 16-bit CPU, 24-bit ΔΣADC, LCD controller/driver, battery back up, AES encryption engine, Data Flash
RX21A Group 32-bit CPU, low power consumption, high capacity memory, 24-bit ΔΣADC(7units, SNDR 85dB), AES encryption engine, Data Flash
Related Boards
Title Document No.
RL78/I1C Evaluation Board