Swiss semiconductor company ST Microelectronics has introduced a biosensing chip for healthcare wearables such as smart watches, sports bands, connected rings and smart glasses.

The ST1VAFE3BX chip combines a high-accuracy biopotential input with STM’s inertial sensing and AI core, which performs activity detection in the chip to ensure faster performance with lower power consumption.

“Wearable electronics are the critical enabling technology for the upsurge in individual health awareness and fitness,” said Simone Ferri, vice president at ST Microelectronics. “Today, everyone can have heart-rate monitoring, activity tracking and geographical location on their wrist. Our latest biosensor chip now raises the game in wearables, delivering motion and body-signal sensing in an ultra-compact form-factor with frugal power budget.”

Analysts at Yole Development (www.yolegroup.com) see opportunities for wearable monitors transcending the general wellness market, including consumer healthcare devices that are approved by health organisations and available over the counter. By creating a complete precision sensor input in silicon, STM’s chip-design experts are facilitating innovation in all segments, with capabilities such as heart-rate variability, cognitive function and mental state.

The chip provides opportunities to extend wearable applications beyond the wrist to other locations on the body, such as intelligent patches for lifestyle or medical monitoring purposes. STM customers BM Innovations (BMI) and Pison (pison.com) are working at the frontiers in this sector and have adopted the sensor to drive product development.

BMI (bm-innovations.com) is an electronic design contracting company experienced in wireless sensing and with a portfolio of projects including several heart rate and performance monitoring systems.

The analogue front-end circuits for biopotential sensors are difficult to design and subject to unpredictable effects such as skin preparation and the position of electrodes attached to the body. The ST1VAFE3BX provides a complete vertical analogue front end (vAFE) that simplifies the detection of different types of vital signs that can indicate physical or emotional state.

“STM’s new biosensor has enabled us to develop the next generation of precise athlete performance monitoring systems including ECG analysis in a chest band or a small patch,” said Richard Mayerhofer, BMI managing director. “Combining the analogue signal from the vAFE with motion data from the acceleration sensor within a compact single package facilitates precise and context-aware data analysis. And with additional support for our AI algorithms directly on the sensor, this is exactly what we have been looking for.”

David Cipoletta, CTO of Pison, a developer focusing on technologies to enhance health and human potential, added: “STM’s new biosensor stands out as great for smartwatch gesture recognition, cognitive performance and neurological health. Leveraging this advancement, we have significantly enhanced the functionality and user experience of our wearable devices.”

The ST1VAFE3BX (estore.st.com/en/st1vafe3bxtr-cpn.html) is in production now in a by 2mm 12-lead LGA package.

Visitors to Electronica (electronica.de), a major industry trade event happening in Munich on November 12 to 15, can see the ST1VAFE3BX in a sensing technologies demonstration at the STM booth, Hall C3, stand 101.

Manufacturers of wellness and healthcare devices can extend their product ranges to include functionality such as electrocardiography (ECG), electroencephalography (EEG), seismocardiography (SCG) and electroneurography (ENG). This can drive the emergence of devices that are affordable, easy to use, and reliably indicate health status or physiological responses to events such as stress or excitement. The future could contain a greater diversity of wearable devices that can contribute towards enhanced healthcare, fitness and self-awareness.

Bringing this precision front end on-chip, the ST1VAFE3BX is building on STM’s competencies in mems (microelectromechanical systems) devices by integrating an accelerometer for inertial sensing. The accelerometer provides information about the wearer’s movement, which is synchronised with the biopotential sensing to help the application infer any link between measured signals and physical activity.

It also integrates STM’s machine-learning core (MLC) and finite state machine (FSM) that enable product designers to implement simple decision trees for neural processing on the chip. These AI skills let the sensor handle functions such as activity detection autonomously, offloading the main host CPU to accelerate system responses and reduce power consumption. In this way, STM’s sensors let smart devices provide more sophisticated functions and operate for longer between battery charging, enhancing usability. STM also provides software tools such as MEMS Studio in the Edge AI suite dedicated to helping designers unleash the performance from the ST1VAFE3BX, including tools for configuring decision trees in the MLC.

The bio-detection signal channel comprises the vAFE with programmable gain and 12bit ADC resolution. The maximum output data rate of 3200Hz is suitable for a wide variety of biopotential measurements to quantify heart, brain and muscular activity.

The device is powered from a supply voltage in the 1.62 to 3.6V range and has typical operating current of 50µA, which can be cut to 2.2µA in power-saving mode. The integrated low-noise accelerometer has programmable full-scale range from ±2g to ±16g.

The ST1VAFE3BX also implements pedometer, step detector and step counting functions.

More information is available at www.st.com/biosensors.