Tech Briefs

The SoC onboards digital signal processing, high-fidelity operation, and multiday monitoring capability with one battery into a single chip.

A new sensor hub integrated as a system-on-chip (SoC) has been designed for use in a broad range of wearable health devices and applications. The SoC was developed by imec, a research and development center for nano-electronics and digital technology, and Holst Centre, an independent R&D center that develops technologies for wireless autonomous sensor technologies and flexible electronics.

Fig.1 – The hub sensor is integrated as system-on-a-chip designed for biomedical wearable devices. (Credit: imec)

The SoC combines an unprecedented number of biomedical analog interfaces into a single chip: onboard digital signal processing, high-fidelity operation, and multiday monitoring capability with a single battery (see Figure 1). Thanks to its small form factor, the SoC can be easily integrated into new innovative wearable designs, enabling maximum user comfort. According to the Holst Centre, the new SoC is designed to be an enabler toward the transformation of today's mainly curative approach to healthcare to one that is preventative, predictive, and personalized.

“There is a clear need for accurate and reliable biosensing in wearables, and we are working on the building blocks to enable this,” said Chris Van Hoof, program director for wearable health at imec. “Our new SoC sensor hub underscores patient-centric capabilities and can be integrated into numerous wearable fitness and healthcare applications such as patch monitors, chest band heart rate monitors, respiration or hydration monitors, and devices for blood pressure calculation.” The biomedical analog interfaces include three ECG channels, photo-plethysmography (PPG), galvanic skin response (GSR), two multifrequency bioimpedance (BIO-Z) channels to support new applications such as impedance-tomography, body fluid analysis, and stroke volume measurements, as well as three reconfigurable channels.

How it Works

While high-performance multimodal analog readouts have been demonstrated, they lack onboard signal processing capabilities, or are too large in size. Alternatively, existing reconfigurable readouts are smaller, but have limited performance. This new SoC moves beyond current solutions and combines advanced biomedical readouts, supported by an ARM Cortex M0+ controller and accelerators for sample-rate conversion, matrix processing, data compaction, and power management circuitry (PMIC).

The PMIC operates from a battery source (2.9–4.5 V) and generates the required voltages for the readout integrated circuit. It supports dynamic voltage scaling optimized for, but not limited to, low-power and high-performance applications, and can be fully customized for specific healthcare applications. The Holst Centre was set up in 2005 by imec (Flanders, Belgium) and TNO (The Netherlands) and is supported by local, regional, and national governments. Holst Centre defines its activities based on global societal trends and emerging markets and applications. The output of its research are generic technologies and knowledge that can be relevant for a variety of application domains.

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