Paolo Motto Ros

A 0.07 mm

This paper presents an ultra-low-power radio receiver implemented only with CMOS logic gates used as basic building blocks and proves its operation. The self-timed duty-cycled system is self-synchronized with the input radio signal, runs a noise-robust baseband detection and does not require any reference besides power supply. Based on S-OOK modulation, the 350-450 MHz digital radio RX occupies an area of 0.07 mm 2 in a 130 nm RFCMOS technology and achieves a 0.1% sensitivity of -63 dBm at 95 kbps, 380 MHz center frequency and 40 μW active power consumption at 1.1 V power supply. At 1.0 V it achieves -62 dBm sensitivity and 33 μW active power at ~ 0.1% error rate. The compact receiver, whose architecture is parametric and technology scalable, suits energy harvested and miniaturized biomedical applications. The paper also presents the potential advantages of asynchronous logic pulse radio and introduces an ad-hoc VHDL model demonstrating RTL-/gate-level accurate error-rate predictions capabilities based on digital simulation only, i.e., without requiring electrical-level co-simulation.

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This paper extends Average Threshold Crossing (ATC) wireless transmission to a multi-channel case by using Address-Event Representation (AER) as the way to convey information. This is encoded in the timings of the transmitted packets which in turn carry the identifier of the event source. By integrating a Impulse RadioUltra Wide Band (IR-UWB) and choosing the proper protocol and modulation, we can aim to minimize the power consumption and provide error detection. The whole system, fully asynchronous, has been implemented in a full-custom chip; besides having multiple independent inputs, it can be configured both to deploy a multi-chip system (with a single receiver) and to optimize wireless transmission parameters. The paper concludes with additional theoretical simulations on the ATC scheme to justify further analyses for our specific application area which regards movement recognition.

Asynchronous Logic CMOS Pulsed Receiver Based on Radio Events Self-Synchronization

The design of a wireless data-glove is introduced in this paper, the aim is to provide an effective and complete solution wherever a tactile sensing system has to be integrated to correctly interact with the surrounding environment (e.g., astronauts extravehicular activity glove). The focus is on the design of the whole system, starting with the readout circuit, the digital signal encoding and ending with the data transmission. The system is made of eight quasi-digital readout circuits to convert the analog information into a pulse-density modulation. The pulse streams are then temporally ordered to form a single streams of events. By integrating a Impulse Radio Ultra-Wide Band (IR-UWB) transmitter and choosing the proper protocol and modulation, we can aim to minimize the power consumption and provide error detection, the design has also taken into account the minimization of the complexity of the receiver. The whole system, fully asynchronous, has been designed as a single full-custom chip, besides having multiple independent inputs, it can be configured both to deploy a multi-chip system (with a single receiver) and to optimize wireless transmission parameters.

A wireless address-event representation system for ATC-based multi-channel force wireless transmission

This paper presents an 130 nm event-driven, all-digital, modular and scalable read-out circuit for capacitive sensors, whose operation is not influenced by either variation of the supply voltage or temperature. The sensing element of the ReadOut Circuit (ROC) is a voltage-controlled ring oscillator, designed to make the system robust to voltage and temperature variations with a dedicated calibration implemented to eliminate offset when no pressure is applied. The ring oscillator is used at the same time as a sensor and a clock signal for the entire event-driven unit. This, in turn, enables to further reduce the thermal drift of the measured capacitance. The sensitivity is 10 fF per LSB, considering a nominal sensing capacitance of 1 pF. The 8 bit output is asynchronously made available with a Parallel-In-Serial-Out register (PISO) after the ROC completes a measurement. The simulated average power consumption is 5.94 μ Wat 1.2V VDD on 1ms operation. The small active area (221×79 μm2) and power consumption make the circuit ideal to be replicated in an array in a cyber physical system, as capacitive pressure sensor in Humanoid Robots.

Wireless Multi-channel Quasi-digital Tactile Sensing Glove-Based System

This paper describes the Micro-for-Nano (M4N) approach as effective solution to overcome challenges related to the nanomaterial assembly with electrodes, the low-noise measurement of nanomaterial electrical properties and the CMOS design of the nanosensor electronic interface. This paper presents both the fabrication process of a nanodevice onto the IC surface using Dielectrophoresis (DEP) and the Read-Out Circuit (ROC) used for the inspection of the electrical properties of nanowires (NW). The ROC includes a Time-over-Threshold circuit which has been characterized stand-alone. It shows maximum measurement error of 0.8% with a maximum linearity error below 1.86% in the range 300kΩ-100MΩ. The ROC occupies 0.0067 mm2 silicon area and simulation data shows that the maximum power consumption is 8.9μW at 1.2 V. The paper presents first measurement results obtained on fabricated prototype chips based on ZnO-NW.

A 130 nm Event-Driven Voltage and Temperature Insensitive Capacitive ROC

STIPER is an Italian national project whose aim is the study of devices to help blind people in daily activities. The core of the portable reader device is based on Artificial Neural Networks, used to recognize characters in real time beyond the fingers of blind people flowing on labels, restaurant menus and other printed objects. Neural Nets outputs are used to drive a Braille matrix, stimulating the fingertips of a blind person, and to speak by means of a common PDA device.

A low-power Read-Out Circuit and low-cost assembly of nanosensors onto a 0.13 μm CMOS Micro-for-Nano chip

The thresholding of Surface ElectroMyoGraphic (sEMG) signals, i.e., Average Threshold Crossing (ATC) technique, reduces the amount of data to be processed enabling circuit complexity reduction and low power consumption. This paper investigates the lowest level of complexity reachable by an ATC system through measurements and in-vivo experiments with an embedded prototype for wireless force transmission, based on asynchronous Impulse-Radio Ultra Wide Band (IR-UWB). The prototype is composed by the acquisition unit, a wearable PCB 23 × 34 mm, which includes a full custom IC integrating a UWB transmitter (chip active silicon area 0.016 mm 2, 1 mW power consumption), and the receiver. The system is completely asynchronous, it acquires a differential sEMG signal, generates the ATC events and triggers a 3.3 GHz IR-UWB transmission. ATC robustness relaxes filters constraints: two passive first order filters have been implemented, bandwidth from 10 Hz up to 1 kHz . Energy needed for the single pulse generation is 30 pJ while the whole PCB consumes 5.65 mW. The pulses radiated by the acquisition unit TX are received by a short-range and low complexity threshold-based 130 nm CMOS IR-UWB receiver with an Ultra Low Power (ULP) baseband unit capable of robustly receiving generic quasi-digital pulse sequences. The acquisition unit have been tested with 10 series of in vivo isometric and isotonic contractions, while the transmission channel with over-the-air and cable measurements obtained with a couple of planar monopole antennas and an integrated 0.004 mm 2 transmitter, the same used for the acquisition unit, with realistic channel conditions. The entire system, acquisition unit and receiver, consumes 15.49 mW.

Artificial Neural Networks for Real Time Reader Devices

We present a fully asynchronous threshold-based IR-UWB receiver which enables a high sensitive distance estimation. It includes an ultra-low power baseband unit which achieves 533 fJ/pulse with an asynchronous, multipath robust and time expiring energy detector, which embeds signal strength in the baseband processing latency to increase sensitivity to TX-RX separation. Asynchronous line-of-sight over-the-air measurements obtained with an integrated all-digital transmitter show a maximum sensitivity of 1mm TX-RX separation per nanosecond system latency. The RX also permits data communication based on the use of self-synchronized modulations.

On Integration and Validation of a Very Low Complexity ATC UWB System for Muscle Force Transmission

This paper introduces and analyzes an ultra-low power and low-complexity analog IR-UWB radio system for unlicensed audio streaming which achieves continuous wave FM performance but exploiting aggressively duty-cycled signaling. At the TX, signal is modulated using a VCO which generates pulses with variable rate (PRF modulation), for an average of ~ 600 kHz. At the RX an asynchronous and interference-robust detector regenerates the modulated signal at half frequency without requiring phase-locking, which is successively processed by a passive FM detector. The obtained demodulated signal is filtered using a fourth order Sallen-Key cell. The TX and RX modules based on commercial components draw 1.89 and 10 mA from 100 mAh Lithium-ion rechargeable batteries (1 × TX and 2 × RX) and include an integrated TX/RX chipset in a 130 nm RFCMOS technology which operates at 3.5 GHz center frequency and 1.2 V supply. The radio system transmits audio with THD 1%, provides an SNR of 64 dB (aligned with FM radio and compact cassettes) and has a frequency response 110 Hz-17 kHz, for a continuous play time of 50 h (TX) and 12 h (RX), and 2.5 m radio range.

A non-coherent IR-UWB receiver for high sensitivity short distance estimation

Electronic systems are increasingly fusing multiple technology solutions exchanging information both at electrical and at non-electrical levels, and in general both analog and digital operation coexists in multiple physical domains. This paper introduces a homogeneous multi-domain design methodology which blurs analog and digital boundaries and enables the design of etherogeneous electrical and non-electrical building blocks. The methodology is based on the identification of four fundamental quantities (quadrivium), namely signal-to-noise ratio, signal-to-interference ratio, impedance and consumed energy, applicable to both electrical and multiphysics components. Based on their constraining and their propagation on an ensemble of transactions in time domain, these four elements can be used across different domains (digital or analog), and permit architects to extract internal features, so that these are intrinsically oriented to successive physical and technology-related implementation and modeling. With example application cases, we show that these four quantities in turn define design constraints of electrical and nonelectrical internal units. After presenting an electronic design example, to show applicability in multiple physical domains, the paper discusses and applies the quadrivium also in the context of a MEMS sensor and microfluidic components.