Julia Pettine

A 345 µW Multi-Sensor Biomedical SoC With Bio-Impedance, 3-Channel ECG, Motion Artifact Reduction, and Integrated DSP

This paper presents a MUlti-SEnsor biomedical IC (MUSEIC). It features a high-performance, low-power analog front-end (AFE) and fully integrated DSP. The AFE has three biopotential readouts, one bio-impedance readout, and support for general-purpose analog sensors The biopotential readout channels can handle large differential electrode offsets ( ±400 mV), achieve high input impedance ( >500 M Ω), low noise ( 620 nVrms in 150 Hz), and large CMRR ( >110 dB) without relying on trimming while consuming only 31 μW/channel. In addition, fully integrated real-time motion artifact reduction, based on simultaneous electrode-tissue impedance measurement, with feedback to the analog domain is supported. The bio-impedance readout with pseudo-sine current generator achieves a resolution of 9.8 m Ω/ √Hz while consuming just 58 μW/channel. The DSP has a general purpose ARM Cortex M0 processor and an HW accelerator optimized for energy-efficient execution of various biomedical signal processing algorithms achieving 10 × or more energy savings in vector multiply-accumulate executions.

A 13

A low-power analog signal processing IC is presented for the low-power heart rhythm analysis. The ASIC features 3 identical, but independent intra-ECG readout channels each equipping an analog QRS feature extractor for low-power consumption and fast diagnosis of the fatal case. A 16-level digitized sine-wave synthesizer together with a synchronous readout circuit can measure bio-impedance in the range of 0.1-4.4 kΩ with 33 mΩrms resolution and higher than 97% accuracy. The proposed 25 mm2 ASIC consumes only 13 μA from 2.2 V. It is a highly integrated solution offering all the functionality of acquiring multiple high quality intra-cardiac signals, requiring only a few limited numbers of external passives.

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A hybrid combination of piezoelectric MEMS resonators and CMOS oscillator readout circuit forms the necessary ingredients of a new generation of electronic nose (e-nose) devices that, owing to their form factor and power consumption, enable a range of novel applications. This paper presents a hybrid low-power, high-resolution e nose system, including the necessary digital interface. An integrated readout was designed for the tracking of resonant frequency shift due to a change in the VOC environment concentration. It interfaces a piezo-actuated functionalized doubly clamped beam resonator that combines low actuation power (μW), high VOC sensitivity but low quality factor in air, large parasitic capacitance and multiple resonance modes. The sensor characteristics translate into a challenging readout design, as high gain-bandwidth product versus low power and low noise are required for optimal detection resolution.

Analog Signal Processing IC for Accurate Recognition of Multiple Intra-Cardiac Signals

This paper reports a battery-powered, multi-parameter recording platform with built-in support for concurrent ECG, Bio-Impedance (BIO-Z), Galvanic Skin Response (GSR) and Photoplethysmogram (PPG). The expanded list of dedicated sensor modalities provides a more accurate, more reliable and broader health assessment in wearable electronics. Since data is collected on one chip, precise synchronization between data streams is possible, allowing to use correlation techniques between the data streams. It supports, e.g., research on blood pressure estimation by combining ECG and PPG measurements through pulse arrival time analysis. Combining different sensing modalities like ECG, PPG, and BIO-Z can result in better estimation of hemodynamic parameters, as well as heartbeat and heart-rate variability.

Power-efficient readout circuit for miniaturized electronic nose

A battery-powered multisensor acquisition system with five dedicated channels [electrocardiograph (50 μW), bioimpedance (46 μW), galvanic skin response (15 μW), and 2× photoplethysmogram (134 μW)] is presented. It includes an ARM Cortex M0, analog and digital filters, timestamp converter and sample rate converter (SRC), and generic interfaces to support additional sensor modalities. The timestamp module makes precise synchronization between the data streams possible. The SRC module makes the sample rates of data from the internal and external sensor readouts compatible with each other, and is up to a factor 35 more energy efficient compared with a software solution. These modules enable performing accurate and reliable (correlation) techniques. The power management includes two buck converters, an LDO, and eight LED drivers, supporting up to 64 LEDs in an 8 × 8 matrix organization. It makes this system the most complete and versatile sensor readout system with state-of-the-art performance (1073 μW with all channels enabled).

28.4 A battery-powered efficient multi-sensor acquisition system with simultaneous ECG, BIO-Z, GSR, and PPG

This work presents a multichannel electronic nose system that enables a range of novel applications owing to high sensitivity, low form factor and low power consumption. Each channel is based on a combination of doubly-clamped piezoelectric MEMS resonators and CMOS oscillator-based readout designed in TSMC 0.25 μm technology. Using “application specific” polymer coatings, the individual resonators can be tuned to detect mixtures of volatile organic compounds (VOCs). This system achieves ppm-level theoretical limit of detection for ethanol which paves the way towards a broad range of applications such as personalized health and environment air quality.

A Multi(bio)sensor Acquisition System With Integrated Processor, Power Management,

This paper presents a power-efficient ASIC for bio-impedance spectroscopy, as well as ECG and respiration recording. The ASIC includes a wideband stimulation current source with a pseudo-random binary sequence, a low-noise instrumentation amplifier, and a low power 12b SAR ADC. This ASIC is able to measure bio-impedances from 1Ω to 10kΩ with 0.1Ω resolution, and covers a frequency range up to 125kHz. Furthermore, the ASIC can simultaneously record ECG and respiration while consuming only 31μW from a 1.8V supply.

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The design of energy efficient instrumentation has long been fueled by the mobile applications where low-power sensors and sensor interfaces have been used for continuous measurement of inertial measurements and environmental parameters. On the other hand, during the last decade, together with the increasing interest on continuous measurements of physiological and neural signals, new generations of energy efficient instrumentation amplifiers have emerged. This paper presents the state of the art of instrumentation architectures in the field of biomedical instrumentation and discusses their use in wearable and implantable biomedical signal acquisition systems.

LED Drivers, and Simultaneously Synchronized ECG, BIO-Z, GSR, and Two PPG Readouts

An electronic nose based on an array of vibrating doubly clamped beams is proposed. These very high aspect ratio (length/thickness) suspended resonators can be individually functionalized by applying polymer coatings by an inkjet printing approach. The absorption of volatile compounds induces a swelling of the polymers that results in axial stress formation and a shift of the resonance frequency. Furthermore, integrated piezoelectric transducers are used for both actuating the resonators, as well as monitoring their resonance frequency in an oscillator loop. This allows for detection at ppm‐level concentrations of low‐molecular weight volatiles.