STMicroelectronics’ Biosensing Innovation Enables Next-Generation Wearable Personal Healthcare and Fitness Devices

Highly integrated biosensor chip combines ECG monitoring and neural sensing signal input channels with motion tracking and embedded AI core

The new products were presented at the Electronica 2024 trade show in Munich from November 12 to 15.

November 6, 2024, China – STMicroelectronics (ST), a world-leading semiconductor company serving multiple electronic applications, has launched a new biosensor chip for next-generation smart wearable medical devices such as smart watches, sports bracelets, smart rings, and smart glasses. The S T1VAFE3BX chip integrates high-precision biopotential input with ST's market-proven inertial sensors and AI cores . Among them, the AI ​​core performs activity detection on the chip, ensuring faster motion tracking and lower power consumption.

“Smart wearable electronics are a key enabling technology for increasing personal health awareness and the fitness boom,” said Simone Ferri, Vice President of STMicroelectronics’ APMS Division and General Manager of the MEMS Sub-Division . “Today, everyone can monitor their heart rate, body movement, and location on a watch. Our latest biosensor chip can enhance the capabilities of wearable devices by enabling motion and biosignal detection in a small, thin form factor and within a tight power budget.”

Analysts at market research firm Yole Development believe that the market growth of wearable monitors has the opportunity to surpass the overall health market, including consumer medical devices approved by health organizations and sold over the counter. By creating a complete and accurate sensor input on the chip, STMicroelectronics' chip design experts are promoting innovation in all areas, providing advanced monitoring functions such as heart rate variability, cognitive function and mental state.

The ST1VAFE3BX opens up opportunities for wearable applications to extend beyond the wrist to other locations on the body, such as smart patches for lifestyle enhancement or medical monitoring purposes. STMicroelectronics customers BM Innovations (BMI) and Pison are at the forefront of innovation in this field and have already used the sensor in the development of new products.

BMI is an experienced electronic design contract company in the field of wireless sensors with a broad portfolio of projects, including several market-leading heart rate monitoring and athlete training monitoring systems. Richard Mayerhofer, General Manager of BMI, said: "With the new biosensor from STMicroelectronics, we can develop the next generation of accurate athlete training performance monitoring systems, including chest strap or small patch ECG analyzers. Integrating the analog signal of the vAFE with the motion data of the accelerometer in a compact package helps us combine contextual awareness information for accurate data analysis. Supporting artificial intelligence algorithms directly on the sensor is exactly the solution we have been looking for."

David Cipoletta, CTO of Pison, a company developing advanced technologies focused on improving health and human potential, added: “ST’s new biosensor is an excellent solution for smartwatch gesture recognition as well as cognitive performance and neuro-health monitoring. Leveraging this technological advancement, we can significantly enhance the functionality and user experience of smart wearables.”

The ST1VAFE3BX is in production now in a 2mm x 2mm 12-pin LGA package and is available from STMicroelectronics’ eSTore website (request free samples) and distributors.

Visitors to the major industry trade show Electronica 2024, taking place in Munich from November 12 to 15, can see the ST1VAFE3BX in a sensor technology demonstration at the STMicroelectronics booth in Hall C3 101.

Technical Details

The design of analog front-end circuits for biopotential sensors is difficult and is affected by unpredictable factors such as skin preparation before detection and the installation position of sensor electrodes on the body. The ST1VAFE3BX provides a full-featured vertical analog front end (vAFE) that simplifies the detection of different types of vital signs indicating physical or emotional states.

Therefore, health product and medical equipment manufacturers can expand their product categories and add monitoring functions such as electrocardiogram (ECG), electroencephalogram (EEG), seismic electrocardiogram (SCG), and electroneurogram (ENG) to their products, triggering a new market for reasonably priced, easy-to-use, and reliable devices that indicate health status or physiological responses to events such as stress or excitement. In the future, there may be more wearable devices that help enhance medical and fitness functions and improve self-awareness.

In addition to integrating this precise analog front end on chip, ST1VAFE3BX also integrates an inertial sensor accelerometer on chip, leveraging ST’s MEMS technology capabilities. This accelerometer provides information about the wearer’s movements, synchronizing data with biopotential sensing signals, helping applications infer the connection between the actual measured signals and physical activity.

The ST1VAFE3BX also integrates ST's machine learning core (MLC) and finite state machine (FSM), allowing product designers to implement simple neural processing decision trees on the chip. These artificial intelligence algorithms allow the sensor to autonomously handle functions such as activity detection, reducing the computing load of the main CPU, speeding up system response, and minimizing power consumption. In this way, ST's sensors enable smart devices to provide more complex functions and have longer battery life, thereby improving the practicality of the device. ST also provides software tools, such as MEMS Studio in the ST Edge AI Suite, to help designers unleash the maximum performance of the ST1VAFE3BX, and also provides MLC decision tree configuration tools.

The biosensing signal channel of the ST1VAFE3BX includes a vAFE front end with adjustable gain and 12-bit ADC resolution. The maximum output data rate of 3200Hz is suitable for various biopotential measurements to quantify heart, brain and muscle activities.

The product operates over a 1.62V to 3.6V supply voltage range and consumes only 50µA typical operating current, which drops to 2.2µA in power-saving mode.

The low-noise accelerometer integrated on the chip has a settable range of ±2g to ±16g. In addition to the machine learning core and programmable finite state machine that can provide functions such as activity detection, the ST1VAFE3BX also has a built-in advanced pedometer that can count walking steps.