Analog Bridges Digital Electronics in IoT Designs

Article By : Majeed Ahmad

Analog is critical to ensuring IoT products are robust and reliable.

The analog side of the Internet of Things (IoT) has always existed. In recent years, however, design engineers realized its importance in making IoT systems robust and reliable.

In the past, IoT engineers mainly focused on the digital side of the IoT. That is, until they discovered that if the processor or microcontroller don’t have the right information from the sensor front-end, any decisions made wouldn’t be accurate because of wrong assumptions derived by a poorly designed analog front-end.

In other words, decisions within the signal chain path are of relevance and in accordance with what is occurring in the environment. As a result, it’s vital to have a low-noise signal chain that can read and accurately interpret data from a sensing element.

In this case, design engineers need accurate, low-noise, precise and high-speed ICs to design reliable and robust IoT systems that can sense the real world and take or suggest decisions that will avoid issues like equipment failures, potentially increasing the overall efficiency in buildings, factories and more.

New analog ICs, such as sensors, amplifiers and analog-to-digital converters (ADCs), are now designed to meet such requirements and improve IoT systems, according to Giovanni Campanella, general manager for building automation at Texas Instruments. He asserted that innovation is occurring at the same pace on both the analog and digital sides.

“On the analog side, sensor signal conditioning communication to the processor, amplifiers, ADCs, digital-to-analog converters (DACs) and transceivers are critical to ensure that the correct information is sensed, read and transmitted with the right timing to the processor,” Campanella said.

Figure 1: Analog and mixed-signal solutions are crucial in IoT devices ranging from sensors to microcontrollers. (Source: Texas Instruments)

While it’s evident that analog circuits can perform certain electronic operations more efficiently than digital circuits, how do analog and mixed-signal circuits facilitate IoT designs? For a start, they are vital in interfacing digital electronics with real-world situations.

Analog as a bridge

With the proliferation of sensors and actuators in IoT applications, analog and mixed-signal circuits have become essential for bridging sensors and actuators with electronic systems. So, IoT applications are driving a higher level of integration between analog/mixed-signal, connectivity, security and intelligent edge processing. Sam Geha, executive VP of IoT, Compute and Wireless Products at Infineon Technologies, cited the example of the integration of Bluetooth connectivity in motor control—a complex, mixed-signal system.

Greg Robinson, VP of marketing for the 8-bit MCU business unit at Microchip, pointed toward another important aspect of IoT design: the increasing number of IoT nodes.

“While IoT networks have become more complex, economics demands smaller and less expensive nodes,” Robinson said. “One way of meeting these opposing demands is to increase the mixing of analog and digital signals by putting more analog functional blocks onto small, cost-efficient microcontrollers.”

While Microchip offers stand-alone mixed-signal devices, it’s also unveiling microcontrollers with advanced analog capability, which expand on the number of applications that can be realized in single-chip designs. This can often lower the cost of each node, enabling large-scale IoT deployments, according to Robinson.

IoT’s analog building blocks

Expanding on analog building blocks, Robinson said that almost every IoT node involves sensing some aspect of its environment.

“Therefore, almost every IoT node needs to read sensor data, process it in some way, and communicate it over a network,” he said. “Sensors that provide an analog output may need amplification or filtering before being processed.” This is an area where MCUs with on-chip operational amplifiers (op amps) can be beneficial, he added.

Digital output sensors may also need I/O level-shifting to interface with digital circuitry. That’s because, in most cases, design engineers will need to convert analog signals to digital, and vice-versa. That, in turn, makes smart on-chip ADCs and DACs key building blocks for such tasks. Additionally, as Robinson pointed out, touch sensing is becoming a common feature in nodes with a user interface, making a perfect use case for advanced on-chip ADCs.

Figure 2: IoT applications are boosting the level of analog integration in chip designs. (Source: Synopsys)

Infineon’s Geha also acknowledged data converters as vital analog building blocks. “ADCs are key for quantizing analog signals so that they can be processed digitally, while DACs are key for converting digital signals from microcontrollers into analog signals for driving actuators.”

Geha presented the example of a voice assistant for smart home applications, where audio signals from microphones and speakers are fundamentally analog, and they must be converted by ADCs and DACs to and from digital signals for artificial intelligence (AI), smart processing and actuation.

“In a highly integrated voice assistant solution, the combination of a low-power analog/mixed signal circuit with a low-power edge processing solution provides wake-on event functionally that saves power in products like voice assistants.”

Geha also mentioned phase-locked–loops (PLLs) required to generate clocks for running microcontrollers. Then there are variable gain amplifiers and filters, which enable optimal and robust usage of IoT sensors and actuators. Switching power supplies are also crucial for enabling IoT systems to tap power sources efficiently as a path toward carbon neutrality. Meanwhile, RF circuits, used for specific analog designs, are key enablers for IoT data transmission.

Analog at the edge

IoT is a broad industry, so more pre-design thought is not only being put on security, but also reliability in relation to analog robustness—particularly with the uptake in automotive requirements. “We expect to see an incremental adoption in analog technologies over the next few years,” said Ron Lowman, strategic marketing manager for IoT at Synopsys.

Furthermore, as IoT solutions migrate to newer nodes, we’re also seeing companies focus more on processors using memory technologies and their analog properties for AI applications, he added. The combination of analog with edge processing to optimize power usage is a perfect example of how analog-based systems are now complementing IoT designs.

 

This article was originally published on EE Times.

Majeed Ahmad, Editor-in-Chief of EDN and Planet Analog, has covered the electronics design industry for more than two decades.

 

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