715 research outputs found
A 110μW [110 mu W] 10Mb/s eTextiles transceiver for body area networks with remote battery power
No full textA transceiver for communicating over an electronic textiles medium is implemented for body area networks. A supply-rail-coupled differential signaling scheme permits time-sharing of the eTextiles medium between communication and remote powering circuits. Fabricated in 0.18 μm [mu m] CMOS and operating at 0.9 V, the chip consumes 110 μW [mu W] at a data rate of 10 Mb/s over a 1 m fabric link.Semiconductor Research Corporation. Center for Circuits and Systems Solutions (Contract 2003-CT-888
A 3 mm x 3 mm Fully Integrated Wireless Power Receiver and Neural Interface System-on-Chip
No full textA miniaturized, fully integrated wireless power receiver system-on-chip with embedded 16-channel electrode array and data transceiver for electrocortical neural recording and stimulation is presented. An H-tree power and signal distribution network throughout the SoC maintains high quality factor up to 11 in the on-chip receiver coil at 144 MHz resonant frequency while rejecting RF interference in sensitive neural interface circuits owing to its perpendicular and equidistant geometry. A multi-mode buck-boost resonant regulating rectifier (<formula><tex></tex></formula>) offers greater than 11-dB input dynamic range in RF reception and less than 1 mV overshoot in transient load regulation. At 10 mm link distance, the 9 <formula><tex></tex></formula> neural interface SoC fabricated in a 180 nm silicon-on-insulator (SOI) process attains an overall wireless power transmission system efficiency (WSE) of 3.4% in driving a 160 μW load yielding a WSE figure-of-merit of 131, while maintaining signal integrity in analog recording and wireless data transmission that comprise the on-chip load.
An energy-efficient all-digital UWB transmitter employing dual capacitively-coupled pulse-shaping drivers
No full textThis paper presents an all-digital, non-coherent, pulsed-UWB transmitter. By exploiting relaxed center frequency tolerances in non-coherent wideband communication, the transmitter synthesizes UWB pulses from an energy-efficient, single-ended digital ring oscillator. Dual capacitively coupled digital power amplifiers (PAs) are used in tandem to attenuate low frequency content typically associated with single-ended digital circuits driving single-ended antennas. Furthermore, four level digital pulse shaping is employed to attenuate RF sidelobes, resulting in FCC compliant operation in the 3.5, 4.0, and 4.5 GHz IEEE 802.15.4a bands without the use of any off-chip filters or large passive components. The transmitter is fabricated in a 90 nm CMOS process and occupies a core area of 0.07 mm2 . The entirely digital architecture consumes zero static bias current, resulting in an energy efficiency of 17.5 pJ/pulse at data rates up to 15.6 Mb/s.United States. Defense Advanced Research Projects Agency (DARPA) (HI-MEMS Contract FA8650-07-C-7704)Natural Sciences and Engineering Research Council of Canada (NSERC
A 440pJ/bit 1Mb/s 2.4GHz multi-channel FBAR-based TX and an integrated pulse-shaping PA
No full textA 2.4GHz TX in 65nm CMOS defines three channels using three high-Q FBARs and supports OOK, BPSK and MSK. The oscillators have -132dBc/Hz phase noise at 1MHz offset, and are multiplexed to an efficient resonant buffer. Optimized for low output power ≈-10dBm, a fully-integrated PA implements 7.5dB dynamic output power range using a dynamic impedance transformation network, and is used for amplitude pulse-shaping. Peak PA efficiency is 44.4% and peak TX efficiency is 33%. The entire TX consumes 440pJ/bit at 1Mb/s.Interconnect Focus Center (United States. Defense Advanced Research Projects Agency and Semiconductor Research Corporation
18.1 An Optically-Addressed Nanowire-Based Retinal Prosthesis with 73% RF-to-Stimulation Power Efficiency and 20nC-to-3μC Wireless Charge Telemetering
No full textRecent approaches toward a functional retinal prosthesis to restore vision in neurodegenerative patients have been limited by the number of pixels that can be individually stimulated. The conventional approach, shown in Fig. 18.1.1 (left), uses an external camera to capture video, whose information is then wirelessly delivered to a hermetic housing (typically a titanium can) for conversion to N distinct stimulation pulses fed transocularly to an N-channel microelectrode array (MEA) placed epi- or subretinally. While this approach has proven long-term biocompatibility, translation to 1000s of channels with hermetic and durable transocular connections is not achievable with current technology, limiting existing designs to at most 256 channels, barely sufficient for 20/400 vision restoration [1] -[3]. Instead, recent work has suggested a full-CMOS solution, where an image sensor, stimulation circuits, and an MEA are integrated directly onto a single CMOS chip, thereby eliminating the interconnect challenge and providing a pathway to scalability [4], [5] (Fig. 18.1.1, middle). However, co-location of photoreceptors, amplifiers, and stimulation circuits imposes difficult fill-factor issues, while also significantly increasing heat dissipation near sensitive ocular and neural tissue due to the need to perform voltage regulation, amplification, and charge-balanced stimulation waveform generation (typical end-to-end efficiency of ~20%) right next to the retina. Most importantly, since the CMOS chip must also include electrodes and yet be sufficiently thin to fit epi- or sub-retinally, current encapsulation methods rely on thin-film deposition to enable patterned electrode windows, which has unproven long-term hemiticity or biocompatibility when encapsulating CMOS which has known biological toxins (e.g., copper), limiting practical implementation
A 16-channel wireless neural interfacing SoC with RF-powered energy-replenishing adiabatic stimulation
No full textThis paper presents a fully-integrated 16-channel wireless neural interfacing SoC that employs an adiabatic stimulator powered directly from a 190-MHz on-chip antenna to eliminate bulky external components while simultaneously avoiding rectifier and regulator losses. Using a charge replenishing architecture, the stimulator outputs up to 145-μA, while achieving a 63.1% charge replenishing ratio and a stimulation efficiency factor of 6.0. Analog front-ends (AFEs) and telemetry circuitry are also included
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Electronic Circuits for Communications and Sensing Applications
No full textThis dissertation addresses two distinct topics, namely circuits for radio-frequency and millimeter-wave transmitters with emphasis on power amplifiers, and control circuits and system design for linearizing atomic magnetometers.Power amplification for wireless transmitters, despite receiving myriad attention over the last few decades, is still one of the main bottlenecks in terms of complete transmitter integration and reducing system power dissipation. First, a distributed amplifier architecture aiming to improve peak efficiency by voltage supply scaling will be presented. By using multiple supplies, wasted headroom is eliminated in the early stages of the distributed amplifier where the output voltage swing is relatively low. Second, a class of Doherty power amplifiers that was rediscovered by the author by reverse engineering the canonical Doherty power amplifier, and a modern implementation, will be presented. The implementation stacks the voltage swings of the main and peaking amplifiers of the Doherty power amplifier, allowing increased output power in scaled CMOS without concern of breakdown. Finally, atomic magnetometers have shown promise as replacements in many applications where SQUIDs are currently used, with the benefits of no supercooling required, and the ability to operate in Earth's geomagnetic field. At the same time, operation outside of a magnetically-shielded environment has numerous side-effects. The last section will present a technique for linearizing the Bell-Bloom atomic magnetometer, improving its performance in interference-rich environments. The technique notes that the detected output signal of the magnetometer contains not only information about the spin precession of the optically pumped atoms, but also a large component due to the pumping laser modulation. By subtracting this known pumping modulation signal from the detected output, the system linearity can be significantly improved
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Low Power Biomedical Signal Acquisition using Frequency Modulation and Frequency Domain Multiplexing
No full textA scheme for the sampling and quantization of voltages over time in an integratedcircuit chip is presented based on first frequency modulating the signal of interestand then sampling and quantizing its frequency modulated representation. Whena single input signal is considered and demodulation to recover the original signal isperformed on the same chip as modulation, the resulting structure is an FM-ADC asdiscussed in Chapter 2. The recording of multiple input signals using multiple frequencymodulating chips and frequency domain multiplexing combined with demodulationoff-chip is referred to as a distributed multi-channel FM-ADC with demodulationoffloading, and is discussed in Chapter 3 as applied to biopotential signal acquisition asit offers unique advantages in that application space. Chapter 4 deals with theoreticaloptimization of the FM-ADC in both its single-channel and multi-channel forms
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Long-range and Battery-less Backscattering Communication Circuits for Self-sustainable IoT
No full textWireless communication is a crucial component of modern Internet-of-Things (IoT) technology. However, the high peak power consumption of popular wireless standards like WiFi and Bluetooth makes it challenging to deploy these technologies in every IoT device, particularly on a large scale. This is because large batteries are required, increasing costs and limiting device miniaturization. To reduce power consumption while maintaining uplink communication from IoT devices to routers or access points, backscattering techniques are employed. These techniques eliminate power-hungry RF circuit blocks by reusing ambient RF signals, while maintaining uplink communication.Historically, backscattering has been used in RFID and NFC applications. Recently, this technique has been extended to WiFi and Bluetooth. However, the semi-passive nature of these systems limits their range, and a truly battery-less backscatter tag has yet to be demonstrated. In this dissertation, long-range WiFi and Bluetooth-compatible backscatter designs are investigated, and a battery-less RFID-like backscatter tag is presented.First, a fully-reflective Van-Atta-array-based backscatter circuit is introduced, demonstrating increased range due to the MIMO gain. Second, a beam-steering MIMO backscatter circuit is presented, showcasing further range extension and more flexible deployment scenarios. Third, to create a fully self-sustainable backscatter tag, an energy-harvesting backscatter tag is proposed to support battery-less operation when a phone is nearby, requiring only a phone firmware upgrade to enable an RFID-like user experience.In summary, this dissertation addresses the critical issue of range limitations in backscatter techniques, a major challenge in the industry. Additionally, the implementation of battery-less tags could enable new low-power wireless IoT applications and support the future development of ambient IoT within the 3GPP and WiFi community
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Energy-Efficient Circuits for IoT Systems
No full textInternet of things (IoT) has greatly improved our understanding and control of the world. By deploying sensors to the environment, different types of environmental parameters can be sensed and with proper processing of the data, such as artificial intelligence, we can observe and control at both the top-level and detail. However, various IoT applications also pose lots of challenges for the integrated circuit design, especially for the power efficiency, speed and size. Solving these problems are the keys to turn the ideas into real and practical design and improve the user experience.In this dissertation, the circuits and systems design of the IoT sensor is presented and discussed. The power management unit (PMU) is an important block in an IoT sensing system, which determines the maximum performance of the circuit. For lots of applications where it is hard to replace the battery and has limited energy source, the efficiency of the PMU also significantly affects the system lifetime. A fast-response-time, high-power-efficiency and dynamic-range change-pump-based LDO is proposed to solve the trade-off between speed, power consumption and stability. The event-driven mechanism and AC-coupled high-Z feedback loop enable fast detection and response speed with low power. The charge-pump with single power transistor architecture helps the LDO achieve a high dynamic range and low ripple over the entire load range. In addition to the power management unit, the clock generation circuit also significantly affects the system performance and power efficiency. Several techniques are proposed to achieve an energy-efficient fast start-up. With the multi-path feedforward negative resistance boosting and dynamic pulse-width injection technique, the start-up time of different frequency XOs can be greatly reduced without a precise injection oscillator. Last, a battery-powered ion-sensing platform is presented and discussed
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