We present an area-and power-efficient applicationspecific integrated circuit (ASIC) for a miniaturized 3-D ultrasound system. The ASIC is designed to transmit pulse and receive echo through a 36-channel 2-D piezoelectric Micromachined Ultrasound Transducer (pMUT) array. The 36-channel ASIC integrates a transmitter (TX), a receiver (RX), and an analog-todigital converter (ADC) within the 250-μm pitch channel while consuming low-power and supporting calibration to compensate for the process variation of the pMUT. The charge-recycling high-voltage TX (CRHV-TX) in standard CMOS generates up to 13.2-V PP pulse while reducing 42.2% peak TX power consumption. Also, each CRHV-TX automatically calibrates excitation voltage according to acoustic pressure of pMUT. The dynamic-bit-shared ADC (DBS-ADC) shares the most significant bits (MSBs) among four channels based on the signal similarity between adjacent channels. The analog front end (AFE) with a received signal sensitivity indicator (RSSI) changes its gain adaptively in real time depending on input signal strength. The ASIC consumes 1.14-mW/channel average power with 1-kHz pulse repetition frequency (PRF) and three TX pulses per cycle. The ASIC in 0.18-μm 1P6M Standard CMOS has been verified with both electrical and acoustic experiments with a 6 × 6 pMUT array.
A 1225-Channel Neuromorphic Retinal Prosthesis (RP) SoC is presented. Existing RP SoCs directly convert light intensity to electrical stimulus, which limit the adoption of delicate stimulus patterns to increase visual acuity. Moreover, a conventional centralized image processor leads to the local hot spot that poses a risk to the nearby retinal cells. To solve these issues, the proposed SoC adopts a distributed Neuromorphic Image Processor (NMIP) located within each pixel that extracts the outline of the incoming image, which reduces current dispersion and stimulus power compared with light-intensity proportional stimulus pattern. A spike-based asynchronous digital operation results in the power consumption of 56.3 nW/Ch without local temperature hot spot. At every 5×5 pixels, the localized (49-point) temperatureregulation circuit limits the temperature increase of neighboring retinal cells to less than 1°C, and the overall power consumption of the SoC to be less than that of the human eye. The 1225-channel SoC fabricated in 0.18 µm 1P6M CMOS occupies 15mm 2 while consuming 2.7 mW, and is successfully verified with image reconstruction demonstration.
A few methods to close and secure cuff electrodes have been researched, but they are associated with several drawbacks. To overcome these, we used magnetic force as a closing method of the cuff electrode. The MENCE can be precisely installed on a target nerve without any surgical techniques such as suturing or molding. Furthermore, it is convenient to remove the installed MENCE because it requires little force to detach one magnet from the other, enabling repeatable installation and removal. We anticipate that the MENCE will become a very useful tool given its unique properties as a cuff electrode for neural engineering.
This paper presents the body-coupled power transmission and ambient energy harvesting ICs. The ICs utilize human body-coupling to deliver power to the entire body, and at the same time, harvest energy from ambient EM waves coupling through the body. The IC improves the recovered power level by adapting to the varying skin-electrode interface parasitic impedance at both the TX and RX. To maximize the power output from the TX, the dynamic impedance matching is performed amidst environment-induced variations. At the RX, the Detuned Impedance Booster (DIB) and the Bulk Adaptation Rectifier (BAR) are proposed to improve the power recovery and extend the power coverage further. In order to ensure the maximum power extraction despite the loading variations, the Dual-Mode Buck-Boost Converter (DM-BBC) is proposed. The ICs fabricated in 40 nm 1P8M CMOS recovers up to 100 μW from the body-coupled power transmission and 2.5 μW from the ambient body-coupled energy harvesting. The ICs achieve the full-body area power delivery, with the power harvested from the ambiance via the body-coupling mechanism independent of placements on the body. Both approaches show power sustainability for wearable electronics all around the human body. Index Terms-Body area network, body-coupled power transmission, body-coupled energy harvesting, energy harvesting, power transfer, impedance matching, rectifier, maximum power point tracking. I. INTRODUCTION OWERING wearable electronics such as earbuds, smart bandaids, and electrocardiography (ECG) sensors are challenging [1]-[3]. The limited battery lifetime incurs charging overhead, causes service disruptions, and inconveniences the users [4][5], which is aggravated further as the number of wearables increases. To address the issue and allow for sustainable operations, power transmission, and energy harvesting approaches have been proposed. Near-field power transmission approaches using the inductive link impose stringent requirements on the alignment Manuscript received DD-MMM-YYYY.
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