Jagdish Nayayan Pandey

A Batteryless 19

This paper presents an ultra-low power batteryless energy harvesting body sensor node (BSN) SoC fabricated in a commercial 130 nm CMOS technology capable of acquiring, processing, and transmitting electrocardiogram (ECG), electromyogram (EMG), and electroencephalogram (EEG) data. This SoC utilizes recent advances in energy harvesting, dynamic power management, low voltage boost circuits, bio-signal front-ends, subthreshold processing, and RF transmitter circuit topologies. The SoC is designed so the integration and interaction of circuit blocks accomplish an integrated, flexible, and reconfigurable wireless BSN SoC capable of autonomous power management and operation from harvested power, thus prolonging the node lifetime indefinitely. The chip performs ECG heart rate extraction and atrial fibrillation detection while only consuming 19 μW, running solely on harvested energy. This chip is the first wireless BSN powered solely from a thermoelectric harvester and/or RF power and has lower power, lower minimum supply voltage (30 mV), and more complete system integration than previously reported wireless BSN SoCs.

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We present progress toward a wirelessly-powered active contact lens comprised of a transparent polymer substrate, loop antenna, power harvesting IC, and micro-LED. The fully integrated radio power harvesting and power management system was fabricated in a 0.13 μm CMOS process with a total die area of 0.2 mm2. It utilizes a small on-chip capacitor for energy storage to light up a micro-LED pixel. We have demonstrated wireless power transfer at 10 cm distance using the custom IC and on-lens antenna.

W MICS/ISM-Band Energy Harvesting Body Sensor Node SoC for ExG Applications

Recent advances in ultra-low power chip design techniques, many originally targeting wireless sensor networks, will enable a new generation of body-worn devices for health monitoring. We utilize the state-of-the-art in low power RF transmitters, low voltage boost circuits, subthreshold processing, biosignal front-ends, dynamic power management, and energy harvesting to realize an integrated reconfigurable wireless body-area-sensor node (BASN) SoC capable of autonomous power management for battery-free operation.

A Fully Integrated RF-Powered Contact Lens With a Single Element Display

Advances in electronic-neural interfaces have shown great potential for both neuroscience research and medical devices. Much of the work to date has focused on short-range inductive links for power and communication transfer [1]. There is an emerging need for active miniaturized systems that stream neural data in the far field, which would enable the observation of brain activity in unconstrained animals such as mice or moths. Such systems cannot rely on near-field power transfer, and must be powered by small batteries or energy harvesters. We present a 500µW fully integrated neural interface that wirelessly streams a digitized neural waveform over 15m.

A batteryless 19μW MICS/ISM-band energy harvesting body area sensor node SoC

The opportunities afforded by using a functional contact lens for remote wireless health status monitoring are discussed and the progress to date in the development of this technology platform is presented. A functional contact lens complete with sensors and embedded circuitry can be used to monitor the composition of tear fluid and, by extension, a number of health-status related parameters in the body in a noninvasive and continuous fashion. The data collected by the disposable contact lens may be sent wirelessly to a mobile phone that, in turn, can relay the information to a medical practitioner via the cellular phone network. If successfully developed and deployed, such a system can be used for monitoring a variety of health indicators over a large geographic area and population distribution with minimal need for the physical presence of health care providers.

A 500µW neural tag with 2µV rms AFE and frequency-multiplying MICS/ISM FSK transmitter

A persistent concern of wireless sensors is the power consumption required for communication, which presents a significant adoption hurdle for practical ubiquitous computing applications. This work explores the use of the home powerline as a large distributed antenna capable of receiving signals from ultra-low-power wireless sensor nodes and thus allowing nodes to be detected at ranges that are otherwise impractical with traditional over-the-air reception. We present the design and implementation of small ultra-low-power 27 MHz sensor nodes that transmit their data by coupling over the powerline to a single receiver attached to the powerline in the home. We demonstrate the ability of our general purpose wireless sensor nodes to provide whole-home coverage while consuming less than 1 mW of power when transmitting (65 ¼W consumed in our custom CMOS transmitter). This is the lowest power transmitter to date compared to those found in traditional whole-home wireless systems.

Functional Contact Lenses for Remote Health Monitoring in Developing Countries

For true low-power peer-to-peer wireless links for sensing, link symmetry must be maintained unlike in [1,2] where the burden is shifted to the receiver. In addition, the transceiver power dissipation and performance should be adaptive to save power when the link distance is short. We present a 120μW MICS/ISM band receiver with −90dBm sensitivity at a data-rate of 200kb/s with BER<0.1%. The receiver incorporates a 44μW low-power (LP) mode that achieves −70dBm sensitivity at 200kb/s and 0.1% BER. At a lower data-rate of 20kb/s, the LP mode can be used as a wake-up receiver with increased sensitivity of −75dBm with 1% BER and 38μW power consumption.

SNUPI: sensor nodes utilizing powerline infrastructure

For fully autonomous implantable or body-worn devices running on harvested energy, the peak and average power dissipation of the radio transmitter must be minimized. We propose a highly integrated 90 µW 400MHz MICS band transmitter with an output power of 20 µW leading to a 22% global efficiency — the highest reported to date for such systems. We introduce a new transmitter architecture based on cascaded multi-phase injection locking and frequency multiplication to enable low power operation and high global efficiency. Our architecture eliminates slow phase/delay-locked loops for frequency synthesis and uses injection locking to achieve a settling time ≪ 250 ns permitting very aggressive duty cycling of the transmitter to conserve energy. At a data-rate of 200 kbps, the transmitter achieves an energy efficiency of 450 pJ/bit. Our 400MHz local oscillator topology demonstrates a figure-of-merit of 204 dB.

A 120μW MICS/ISM-band FSK receiver with a 44μW low-power mode based on injection-locking and 9x frequency multiplication

The overarching goal of an active contact lens is to integrate sensing or display functionality onto a wearable device, enabling on-lens medical monitoring and heads-up displays. We present progress toward a wirelessly-powered active contact lens comprising a transparent polymer substrate, loop antenna, power harvesting IC, and a custom micro-LED. The fully integrated radio power harvesting and a power management system was fabricated in a 0.13μm CMOS process and utilizes a small on-chip capacitor as an energy storage element to light up a microLED pixel. We have demonstrated wireless power transfer and LED intensity control using the custom IC and on-lens antenna.

A 90µW MICS/ISM band transmitter with 22% global efficiency

Efficient, miniaturized wireless recording is critical for both existing and emerging health-monitoring applications. One important example of this is in the brain interface community, where new technologies allow improved observation and understanding of brain functions. This, in turn, drives the need for ever smaller, lower power, and higher performance circuitry for chronic recording. This paper describes circuit and system techniques for low power wireless brain interfaces. Active and passive architectures are described and compared, and measured in-vivo data from both are presented.