The Internet of Things (IoT) devices used for intelligent lighting and building automation are undergoing rapid evolution, with their roles shifting from simple control nodes to feature rich interconnected systems. These systems need to support higher computing requirements, robust security performance, and higher radio frequency (RF) performance. Faced with this trend, designers are under increasing pressure to balance diverse requirements such as multi protocol connectivity, advanced security features, and power efficiency, while also striving to reduce bill of materials (BOM) costs and system complexity. The key to addressing the demands of these emerging IoT applications lies in adopting advanced wireless System on Chip (SoC) devices.
This article aims to elaborate on the challenges faced by designers of emerging IoT devices and systems, and then introduce how Silicon Labs' next-generation wireless IoT SoC addresses these challenges through its ultra-low power architecture. This architecture combines high-performance processors with multiple dedicated subsystems, providing a feasible solution.
How diversified demands drive the evolution of devices towards higher integration
Line powered smart devices used in applications such as LED lighting, smart sockets, and switches are increasingly expected to provide richer functionality in shorter development cycles. The designers of these devices face a series of stringent requirements: they need to integrate higher processing capabilities, multiple wireless standards, and robust security performance while strictly controlling BOM costs and ensuring predictable behavior of the devices in a continuous operating environment.
The complexity of wireless connections exacerbates these pressures. Low energy Bluetooth (BLE), Zigbee, Thread, and Matter protocols are increasingly coexisting, making solutions based on a single protocol or multi chip architecture complex. Supporting multiple heterogeneous protocols through external components may slow down development progress and result in low efficiency. Therefore, IoT design has shifted towards using single-chip wireless SoCs, such as Silicon Labs' SiMG301/SibG301 3-series wireless SoC (Figure 1). This type of chip integrates application processing, security functions, and wireless operations into a single device.
Advanced wireless IoT SoC integrates the entire functional stack schematic diagram
Figure 1: The advanced wireless IoT SoC integrates the entire functional stack, achieving higher design efficiency compared to early multi chip solutions. (Image source: Silicon Labs)
These SoCs, with their advanced architecture, can provide high performance, robust security, and flexible connectivity capabilities, enabling designers to more effectively respond to the rapidly changing demands of smart devices.
Integrated architecture can meet the diverse needs of emerging IoT applications
The SixG301 series integrates all the functions required for line powered intelligent devices. In order to meet the increasingly complex computing requirements, the SixG301 SoC is based on a 150 MHz Arm Cortex-M33 processor core with digital signal processing (DSP) instructions and floating-point arithmetic units (FPUs) (Figure 2). The processor subsystem combines the core with on-chip random access memory (RAM), co packaged flash memory, direct memory access (DMA) controller, and debugging interface. This architecture also provides comprehensive support for smart devices through dedicated hardware modules for connectivity, security, energy management, clocks, timers, and peripherals (including dedicated functions for LED lighting).
Schematic diagram of EFR32BG22 SoC architecture from Silicon Labs (click to enlarge)
Figure 2: The SixG301 wireless SoC architecture integrates application processing, wireless connectivity, and security, providing scalable performance and reducing system complexity for line powered smart devices. (Image source: Silicon Labs)
For designers, the SixG301 series provides a scalable solution that can meet a wide range of requirements. In order to achieve smart device design with Bluetooth connectivity as the goal, the SiBG301 Bluetooth SoC series supports BLE, Bluetooth mesh networks, and proprietary 2.4 gigahertz (GHz) applications. The SiMG301 multi protocol SoC series not only supports the same Bluetooth options, but also adds support for IEEE 802.15.4 physical layer (PHY) and media access control layer (MAC), suitable for low data rate wireless networks, including Zigbee, Matter over Thread, and OpenThread. Within each series, different models also offer additional configuration options, providing up to 512 KB of RAM and 4 MB of secure on-chip execution (XIP) quad channel serial peripheral interface (QSPI) flash memory. Regardless of the configuration chosen, all members of the SixG301 SoC series possess the same core capabilities required for the next generation of IoT devices.
Advanced IoT applications rely on robust connectivity, and the SixG301 series is designed to operate reliably even in high-density, interference prone environments typical of these applications. This series of low-power wireless (LPW) radios (Figure 3) integrates a radio processor core, RAM, and dedicated transmit and receive signal paths, providing a complete connectivity subsystem.