Introduction

As the demand grows for smarter, networked, and locally responsive solutions in buildings, homes, and factories, there is a corresponding need to redesign electrical control equipment, including circuit breakers and their management and monitoring gateways.

In addition to traditional functions like short-circuit protection, overload protection, and leakage protection, modern circuit breakers also incorporate new smart features. These include real-time circuit and device status feedback and logging via various networking interfaces such as RS485, RJ45 (Ethernet), Wi-Fi, Bluetooth, and 4G/5G for remote control. Internally, smart circuit breakers and gateways require high-speed CAN bus communication for interconnectivity.

Users can adjust parameters using mobile apps or computer terminals for remote monitoring. These adjustments include setting rated current values, configuring leakage trip thresholds, defining overvoltage or undervoltage limits, and establishing temperature protection parameters. This flexibility allows users to customize settings based on specific operational needs. With the increasing adoption of cloud connectivity and remote management, robust chip-level security features are crucial to safeguard data integrity and prevent unauthorized access.

To meet these evolving demands, smart circuit breakers and gateways require redesign of advanced components such as MPUs, M4 processors, and BLE MCUs. The following details highlight Nuvoton's product solutions designed to support these applications.

For smart circuit breaker requirements, Nuvoton provides relevant M4 products:

a. High Computational Capability Required:

• The M463/M467 series can reach up to 200MHz, and the M483 series up to 192MHz, both equipped with DSP/FPU floating-point processing units.

b. Large Memory Capacity Supporting Real-time Operating Systems:

• The M463/M467 series provides up to 1024KB Flash and 512KB RAM.
• The M483 series provides up to 512KB Flash and 160KB RAM.

c. Rich and Redundant Peripheral Interfaces:

• The M463/M467 series offers up to 4 CAN FD and 10 channels UART + ISO7816/UART 3 channels.
• The M483 series offers up to 3 CAN and 8 channels UART + ISO7816/UART 3 channels.

d. Multi-channel ADC Collection (over 20 channels) with 12-bit ADC:

• The M463/M467 series provides 5 MSPS, 12-bit ADC, supporting up to 28 channels (up to 3 ADC groups).
• The M483 series provides 5 MSPS, 12-bit ADC, supporting up to 24 channels (up to 2 ADC groups).

e. Abundant Pin Counts:

• The M463/M467 series offers GPIO corresponding to LQFP64 (44), LQFP128 (100), LQFP144 (114), LQFP176 (146).
• The M483 series offers GPIO corresponding to LQFP64 (52), LQFP128 (100).

 M463/M467 Series Selection

M483 Series Selection

M4 series in smart circuit breakers Application

Low-end and High-end Circuit Breaker Gateway Applications:

For various application scenarios, such as smart buildings requiring low-end gateways, the functionality must include breaker control via CAN bus, cloud uploads, sensor signal processing, and real-time RTOS operation. On the other hand, high-end gateways demand significant computational power for lightweight edge computing, faster CAN FD bus for real-time breaker control, and robust hardware-software security mechanisms to ensure data transmission security. Nuvoton offers the NUC980 series and MA35D1 to assist customers in meeting diverse requirements.

Nuvoton provides the NUC980 series as the ideal choice for low-end smart circuit breaker gateways:

 a. Perfect balance of cost-effectiveness and performance:

• High-performance, low-cost core processor running at speeds up to 300MHz.

b. Built-in 64MB/128MB DDR@LQFP MCP package advantages:

• Reduces layout complexity and minimizes PCB size and layers (cost reduction).
• Lowers product PCB manufacturing process requirements / Reduces product EMI radiation intensity.
• Can replace high-end MCUs like M4 or M7.

c. Rich and redundant peripheral interfaces:

• Supports 2 sets of 10/100Mbps Ethernet
• Supports 10 UART ports (hardware PDMA, 3Mbps)
• Supports 2 USB 2.0 Host ports
• Supports 4 CAN buses
• Supports EBI expansion
• Includes hardware encryption engine (Crypto Engine)

d. Advantages of multi-operating systems:

• Supports RT-Thread/Linux

NUC980 Series Selection

NUC980 Series in Low-end Smart Circuit Breaker Gateways Application

For high-end smart circuit breaker gateways, Nuvoton offers the MA35D1 series as an ideal choice:

a. Requires high computational power for lightweight edge computing:

• Dual-core 64-bit Arm® Cortex®-A35 (800MHz) and Arm® Cortex®-M4 (180MHz) heterogeneous core architecture.

b. Large embedded SDRAM supports Linux and real-time operating system RT-thread:

• Built-in DDR3L SDRAM stack with a capacity of up to 512 MB.

c. Rich and redundant peripheral interfaces:

• 4 sets of PDMA
• 2 Gigabit Ethernet ports
• 1 SDIO 3.0, 1 SDIO 2.0
• 1 USB 2.0 high-speed host, 1 dual-role USB 2.0 high-speed host and device
• 4 CAN FD
• 2 QSPI
• 2 I2S
• 4 SPI/I2S
• 17 UART
• 6 I2C

d. Comprehensive security mechanisms to address network risks:

• TrustZone technology
• Secure Boot
• Trusted Security Island (TSI), an isolated secure hardware unit for all security-related operations
• Hardware encryption engine: AES256, SHA512, ECC, RSA4096, SM2/3/4
• True random number generator (TRNG)
• 8Kbit one-time programmable memory (OTP memory) with key storage functionality

MA35D1 Series Selection

MA35D1 Series in High-end Smart Circuit Breaker Gateways Application

For wireless breaker connectivity, Nuvoton offers the M031BT/M032BT BLE MCU:

• Arm® Cortex®-M0 core operates at speeds up to 72 MHz.
• Flash memory capacity up to 512 KB, with 96 KB of SRAM.
• Packages: M031BT in QFN48 (5 x 5 mm) / M032BT in QFN68 (8 x 8 mm).
• Supports dual-mode Bluetooth Low Energy (BLE) 5.0 and 2.4 GHz wireless transmission technologies.
• Air transmission rates: 1 Mbps and 2 Mbps.
• High transmission power: +8 dBm @1 Mbps.
• Receiver sensitivity: −94 dBm @1 Mbps.
• Supports PHY, Link Layer, and Host certifications.

M031BT/M032BT BLE MCU Series Selection