A Low-Power Sigma-Delta Modulator for Healthcare and Medical Diagnostic Applications

This paper presents a switched-capacitor Sigma-Delta modulator designed in 90-nm CMOS technology, operating at 1.2-V supply voltage. The modulator targets healthcare and medical diagnostic applications where the readout of small-bandwidth signals is required. The design of the proposed A/D converter was optimized to achieve the minimum power consumption and area. A remarkable performance improvement is obtained through the integration of a low-noise amplifier with modified Miller compensation and rail-to-rail output stage. The manuscript also presents a set of design equations, from the small-signal analysis of the amplifier, for an easy design of the modulator in different technology nodes. The Sigma-Delta converter achieves a measured 96-dB dynamic range, over a 250-Hz signal bandwidth, with an oversampling ratio of 500. The power consumption is 30 μW, with a silicon area of 0.39 mm²

Low-power humidity read-out circuit in CMOS 180-nm for RFID sensors

The manuscript describes the design and implementation of a read-out circuit for the measurement of the Relative Humidity by means of an external capacitive sensor. The circuit is based on a timer oscillator and a digitally calibrated resistor which are available in an integrated circuit implementing the functions of sensing and data logging. Thanks to the reusing concept low power consumption and small silicon area are achieved. An accuracy of a few percent is obtained by means of a relatively inexpensive one-point calibration. In addition a circuit interfacing between the oscillator and the external capacitor sensor is proposed

Fully differential operational amplifier

A fully differential operational amplifier is provided. The amplifier has input nodes and includes a differential input stage for receiving input signals over the input nodes and providing output signals on first and second intermediary nodes. The amplifier includes a fully differential amplification stage having positive and negative inputs coupled to the first and second intermediary nodes, respectively. The amplifier includes a first compensation transistor having conduction terminals coupled to the first intermediary node and a first node, and a control terminal coupled to a negative output of the fully differential amplification stage. The amplifier includes a second compensation transistor having conduction terminals coupled to the second intermediary node and a second node, and a control terminal coupled to a positive output of the fully differential amplification stage. The amplifier includes positive and negative output stages for providing amplifier outputs and feeding the outputs back to the amplifier

Accurate Modeling of Ultra Low-Power Σ∆ Modulator

This paper presents a behavioural model suitable for the simulation of low-power Sigma-Delta Modulators. Second- order effects affecting the settling behaviour of the switched- capacitor integrator was included, leading to improved accuracy. Due to the oversampling mode of the converter, transistor-level simulations are extremely time consuming. Accurate behavioural models are thus mandatory in the first design phase of the modulator, in particular when the involved analog blocks must be optimized for minimum power consumption at some converter resolution

An extended temperature range UHF RFID front-end in CMOS 350 nm

This paper describes the architecture and the transistor-level implementation of a UHF RFID front-end designed in CMOS 0.35μm technology with limited analog options to comply with EPC Class1/Generation2 standard. Since power acquisition is critical to RFID tag performance, two rectifier architectures are proposed and their performance is assessed by simulation in extended temperature range. In spite of technology constraints, good performance and low power consumption are obtained by the RFID front-end

Low-power 3^rd order ΣΔ modulator in CMOS 90-nm for sensor interface applications

The manuscript describes the design and implementation of a low-power, fully differential switched-capacitor ΣΔ modulator in STM 90-nm CMOS technology, for sensor interface applications. With the aid of an accurate behavioral model, the power consumption is minimized without sacrificing the effective resolution. Through the optimization of single-stage integrators, with feed-forward summation, and using a class-A OTA op-amp with local positive feedback, a total power consumption of 50-μW from a 1.2-V power supply is achieved. The modulator reaches a peak SNR of 94-dB and a noise floor of 8.6-μV-rms over a 250-Hz signal bandwidth. The proposed design is one of the first modulator implemented in a 90-nm CMOS and achieving a 16-bit effective resolution with a 1.5-pJ/conv. figure-of-merit

Scienze sociali ed emancipazione. Tra teorie e istituzioni del sapere

Il volume prende avvio da un’attività di riflessione e confronto avviata nel corso degli ultimi anni sulla capacità delle scienze sociali di riuscire a stare in relazione significativa con i mondi, le questioni e gli attori di cui si compone la società e di essere in grado di elaborare un sapere critico che possa divenire strumento di interlocuzione e di intervento nei processi sociali. La questione non è di poco conto, dal momento che attiene alla possibilità delle scienze sociali di riuscire tuttora ad ispirare e/o attivare pratiche di resistenza rispetto ai processi di assoggettamento, alle forme di marginalizzazione e alle pratiche di sfruttamento ed esclusione prodotte dal sistema capitalista neoliberista. Sotto questo profilo, in diversi contesti, già da alcuni anni si fanno strada filoni di ricerca sociale critica che sembrano esprimere un rinnovato protagonismo. Negli Stati Uniti E.O. Wright ha proposto una scienza sociale ‘emancipativa’ espressamente rivolta a legittimare forme di critica al tardocapitalismo contemporaneo, per comprendere e dare visibilità a forme possibili di contro-organizzazione sociale, e generare così una conoscenza scientifica in grado di sfidare forme emergenti di sfruttamento. In America Latina si moltiplicano nelle università nuove ‘ecologie’ di saperi, cioè percorsi didattici e di ricerca in chiave radicalmente pluridisciplinare legati a istanze poste dai cittadini, secondo pratiche di interazione non dissimili dall’idea di ‘ricerca sociale democratica’ portata avanti a Mumbai da A. Appadurai. Ma anche in Europa, B. de Sousa Santos, L. Boltanski e molti altri provano a tradurre in futuro gli approcci della sociologia critica che caratterizzarono i decenni centrali del ’900 e che già indicavano nei pubblici plurali di cui si compone la società – più che nei circuiti ristretti dei colleghi – gli interlocutori privilegiati per la costruzione del disegno di ricerca e la gestione della vita sociale dei dati prodotti. Oggi tutto ciò avviene, però, con la marcata consapevolezza che occorra promuovere una nuova stagione di ‘risoggettivazione reciproca’ tra ricercatori e attori sociali che passi anche attraverso la capacità immergersi e lasciarsi interpellare dalla dimensione narrativa, esperienziale, esistenziale di processi sociali invisibili, turbolenti, scomodi, difficilmente accessibili, ma in qualche modo emblema profondo dell’attuale complessit