Powering the Wearables of the Future

Article By : Stephen Las Marias

Wearable healthcare devices continue to add more clinical sensing capabilities, allowing more comprehensive remote patient monitoring solutions.

New innovations in vital signs sensing are accelerating the availability of patient data to ensure a more holistic approach to healthcare. Wearable healthcare devices continue to add more clinical sensing capabilities, allowing more comprehensive remote patient monitoring solutions.

Worldwide, healthcare costs continue to grow at a higher rate than inflation, with a total spend currently at $9 trillion worldwide. Increased remote patient monitoring reduces costs as well as improve short- and long-term outcomes, improving overall quality of life.

According to Andrew Baker, Managing Director of Healthcare, Industrial & Healthcare Business Unit, at Analog Devices Inc., healthcare delivery has traditionally been centralized at a care facility. Patients must travel there for any kind of monitoring or treatment. This may consist of long-distance travel, and inconvenience due to work and family care commitments.

“Decentralized healthcare delivers convenience, as remote monitoring does not necessitate travel and individuals can go about their daily lives with very little to no disruption,” says Baker. “Continuous remote monitoring increases the chance of early detection, improving the chance of successful treatment and better outcomes.” And better outcomes translate to lower overall cost of healthcare delivery, and happier, healthier patients.

In addition, remote continuous monitoring enables collection of statistically relevant data to be analyzed and processed to make data-driven decisions. And data analytics continuous to drive towards even higher levels of efficacy with research and continuous innovation.

According to Yole Développement, the wearable health and wellness market is set to grow from 347 million units in 2019 to 754 million units in 2025, with a compound annual growth rate (CAGR) of 14% from 2019 to 2025. This growth is mainly fueled by both medical wearable devices and consumer wearables, which all have a potential for multiple sensing of body vital signs. And this presents a large opportunity for system solutions provider like Analog Devices.

“To satisfy the needs of clinicians and consumers, additional health sensing needs to be enabled in the wearables of the future. This will allow a more holistic approach to remote healthcare, enabling better monitoring of body vital signs to improve predictive and preventive outcomes, as well as better management of chronic diseases,” says Baker.

Targeting this segment, Analog Devices has released the MAX86178 triple-system vital signs analog front end (AFE), which helps simplify the design of wearable remote patient monitoring (RPM) devices by measuring four vital signs. This single-chip AFE integrates three measurement systems—optical, ECG and bio-impedance—to obtain four common vital signs: electrocardiogram (ECG or EKG), heart rate (ECG or optical PPG), blood-oxygen saturation (SpO2) and respiration rate (using BioZ).

With three clinical-grade subsystems integrated into one IC, the MAX86178 triple system AFE replaces discrete implementations by integrating an optical PPG sub-system to measure heart rate and SpO2, a single lead ECG sub-system, as well as a biopotential and bioimpedance (BioZ) sub-system to measure respiration rate. It permits small vital signs devices by fitting those multiple functions into a 2.6mm x 2.8mm package.

In addition, next-generation wearable RPMs need to operate at low power to permit smaller batteries or extend battery life to allow more convenient charging requirements. To enable ultra-low power features, the MAX86178 provides each subsystem with configurable options to optimize battery life for specific use cases.

Powering the next generation of consumer and medical wearable devices.

With the increasing arrival of diagnostic devices in the market, most are moving to the battery powered world. “What this means for analog power system designers, for companies like Analog Devices, is we need to innovate and create a combination of power management solutions that works very well with Andrew’s best-in-class sensor solutions,” says Karthi Gopalan, Executive Director, Multifunction Power Battery Power Solutions Business Unit, Analog Devices. “This combined solution has to guarantee the lowest power consumption, it needs to be the smallest form factor, and of course, the signal quality has to be topnotch.”

According to Gopalan, one of the major trends happening right now is that human vitals monitoring is moving from the doctor’s clinic to people’s ‘wardrobe’, “our homes, our living rooms, our family and such.”

“One of the things that we saw with COVID-19 was a major paradigm shift in the world of wellness,” says Gopalan. She says before 2020, mostly the elderly and people who were chronically sick were the ones who did vitals monitoring on a daily basis.

“But last year, what happened is like healthy people have started buying pulse oximeter, we started measuring our temperatures, because we wanted to protect our family. So, this meant there was a big wellness tracker world, heartrate monitors, and all of that,” says Gopalan. “Now, the second major trend, as most of us have become demanding and discerning about our own healthcare and our family’s healthcare, we have noticed that consumer electronics manufacturers, those who made the traditional smartwatches and the hearing devices, more and more of them now are adding very accurate vitals monitoring onto their systems.”

Gopalan says as more consumer electronics companies enter the vitals monitoring market, traditional medical device manufacturers—who used to make big, thick gadgets in the past because they are just for typical vitals monitoring—now have to compete.

“They are now looking at design—making their devices very sleek and attractive,” says Gopalan. “We are noticing that both the consumer and the medical world, they are merging towards one mission of serving us. The two markets are merging, but at the same time, there’s enough volumes for all these companies to thrive.”

Now, there are several challenges these wearable device manufacturers need to address. One of which greater comfort.

“People like us, we wear it for a long time, so that means the part needs to be very soft on our skin, it cannot burn our skin, it needs to be small,” says Gopalan. “So, comfort plays a major role. Accuracy, obviously, because this is vitals monitoring, so we need precision measurement. And then in general, as consumers, we want a long battery life so that we don’t have to keep charging the device frequently.”

That means the solutions should have the highest efficiency with the longest battery life. Fast charging is also very important, says Gopalan. “You don’t have time to wait and see if the gadget is charging or not, you are very focused on fast charging. That is something that this market wants right now. And above all, what do you do with all the data that’s coming in? It needs to be accurate—but to get accurate data, you have to integrate more features, and you need to have stronger processing power for that particular data processing,” she notes.

Gopalan says the next-generation solutions require more precision sensors. “You will have a lot more of those sensors, and then you will have AI-based processing, because you have to have smart processing. And then on top of it, you need a switching charger, we need GPS tracking, audio feedback, haptic feedback, and so forth,” says Gopalan.

As next-generation wearables are very feature-rich, they therefore have lots of hardware components. “All that has to be packed into very small form-factor, very thin gadgets,” says Gopalan. “That is where Analog Devices is able to help you with this very unique power management IC.”

Analog’s new MAX77659 single-inductor multiple output (SIMO) power management IC (PMIC) with integrated switch-mode buck-boost charger charges wearables, hearables, and IoT devices faster and in less space than any other PMIC available today. Delivering over four hours of play time after a short, 10-minute charge, the MAX77659 SIMO PMIC uses a single inductor to power multiple rails, reducing the bill of materials (BOM) by 60 percent and shrinking total solution size by 50 percent.

The MAX77659 SIMO PMIC integrates a switch-mode buck-boost charger and three independently programmable buck-boost regulators, all sharing a single inductor to minimize total solution size. The regulators extend battery life by operating at 91 percent efficiency during moderate to heavy load conditions while consuming only 5µA of quiescent current during light load conditions.

The MAX77659 SIMO PMIC supports autonomous headroom control, which reduces heat dissipation by minimizing the voltage drop while providing enough headroom to regulate the charging current. It brings the ‘on-the-go’ lifestyle to the next level by minimizing plug-in time and maximizing play time. Finally, the MAX77659 PMIC frees up board real estate to pack in additional features such as expanded memory storage, location tracking and vital sensing demanded by today’s portable consumer and medical devices.

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