Wristband health monitors connected to the Internet can measure heart rate and blood pressure.

Upstream suppliers are developing highly integrated and low-power solutions.

Health and fitness devices are an inherent part of wearable computing and the Internet of Things. These sensing nodes provide vital personal information, which can be used in preventive medicine and help reduce healthcare costs. In response to this burgeoning application sector, makers of medical electronics components are working on the integration of sensing features in wafer-level chip scale packages or WCSPs. They also have low power consumption on the agenda to enable devices to run for five to seven days on a single battery charge.

IC solutions for sensing biological signals for healthcare uses in hospitals have existed for decades. Chipmakers such as Texas Instruments Inc. offer specific products for electrical, optical and impedance measurements. “However, the rapidly emerging wearable market and the increasing demand for remote patient monitoring bring in significant challenges for biosensing in terms of form factor and power consumption,” said Karthikeyan Soundarapandian, TI’s health and fitness segment manager. “Packaging technologies that were never thought of for traditional healthcare applications are becoming the standard for health and wellness devices.”

An example of this transformation is an analog front-end component for PPG measurements from TI. The AFE4400 chip in 6x6mm package is widely adopted in conventional healthcare products. The latest AFE4403 version in a 3x3mm WCSP is becoming the norm for wearable uses.

Most wellness devices on the market today utilize MEMS sensors as accelerometers to measure information on user movement. These make generic estimations on the activity level based on parameters such as calorie expenditure. Though the products are a first big step toward self-tracking, significant improvements can be made by measuring biological signals directly.

“In coming years, we expect devices to have more sensors in the activity monitor for optical, electrical and impedance signals,” said Soundarapandian. “With these extra information, the devices would have the capability to include additional parameters, including heart rate, oxygen saturation and beyond. They will be able to provide better intelligent feedback to end users on their lifestyle behavior patterns, and suggest ideas to improve the quality of life.”

SoCs dominate wellness market

Given the constraints on space, SoCs with integrated MCUs and wireless interface are favored in medical electronics. The analog front-end components handling biological signals are preferred to be separate in a high-performance analog process node to maintain performance.

A major difference between clinical and wellness products is life cycle. The former undergoes a long validation process to ensure performance across multiple subjects with varying ethnicity, age group, gender and health conditions.

With the fast product development for wearable devices, some releases do not go through adequate verification. This, in turn, leads to a wide gap between the expected and actual performance of some products being launched.

“This presents a real danger in market adoption for these upcoming fitness technologies,” Soundarapandian said. “Hence, high precision will be one of the key parameters on top of power consumption. Typically, speed is not a big concern when dealing with biological signals.”

Personal healthcare devices and out-of-hospital activity monitors are not new but they did not take off in the past as expected due to the nonavailability of a wireless infrastructure.

Today, the adoption of medical and healthcare devices in the consumer market will heavily depend on product interoperability in various platforms and compatibility with existing technologies such as Bluetooth and its low-energy version or BLE, said Soundarapandian. BLE is becoming the de facto standard adopted by most wearables manufacturers.

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