A low power and low signal 4 bit 50MS/s double sampling pipelined ADC for Monolithic Active Pixel Sensors

International audienceA 4 bit very low power and low incoming signal analog to digital converter (ADC) using a double sampling switched capacitor technique, designed for use in CMOS monolithic active pixels sensor readout, has been implemented in 0.35μm CMOS technology. A non-resetting sample and hold stage is integrated to amplify the incoming signal by 4. This first stage compensates both the amplifier offset effect and the input common mode voltage fluctuations. The converter is composed of a 2.5 bit pipeline stage followed by a 2 bit flash stage. This prototype consists of 4 ADC double-channels; each one is sampling at 50MS/s and dissipates only 2.6mW at 3.3V supply voltage. A bias pulsing stage is integrated in the circuit. Therefore, the analog part is switched OFF or ON in less than 1μs. The size for the layout is 80μm*0.9mm. This corresponds to the pitch of 4 pixel columns, each one is 20μm wide

A low power and low signal 5-bit 25MS/s pipelined ADC for monolithic active pixel sensors

For CMOS monolithic active pixels sensor readout, we developed a 5 bit low power analog to digital converter using a pipelined architecture. A non-resetting sample and hold stage is included to amplify the signal by a factor of 4. Due to the very low level of the incoming signal, this first stage compensates both the amplifier offset effect and the input common mode voltage dispersion. The converter consists of three 1.5 bit sub-ADC and a 2 bit flash. We present the results of a prototype, made of eight ADC channels. The maximum sampling rate is 25MS/s. The total DC power consumption is 1.7mW/channel on a 3.3V supply voltage recommended for the process. But at a reduced 2.5V supply, it consumes only 1.3mW. The size of each ADC channel layout is only 43μm*1.43mm. This corresponds to the pitch of two pixel columns each one would be 20μm wide. The full analog part of the converter can be quickly switched to a standby idle mode in less than 1μs; thus reducing the power dissipation to a ratio better than 1/1000. This fast shutdown is very important for the ILC vertex detector as the total DC power dissipation becomes directly proportional to the low beam duty cycle

A low power and low signal 4 bit 50MS/s double sampling pipelined ADC for monolithie active pixel sensors

A 4 bit very low power and low incoming signal analog to digital converter (ADC) using a double sampling switched capacitor technique, designed for use in CMOS monolithic active pixels sensor readout, has been implemented in 0.35μm CMOS technology. A non-resetting sample and hold stage is integrated to amplify the incoming signal by 4. This first stage compensates both the amplifier offset effect and the input common mode voltage fluctuations. The converter is composed of a 2.5 bit pipeline stage followed by a 2 bit flash stage. This prototype consists of 4 ADC double-channels; each one is sampling at 50MS/s and dissipates only 2.6mW at 3.3V supply voltage. A bias pulsing stage is integrated in the circuit. Therefore, the analog part is switched OFF or ON in less than 1μs. The size for the layout is 80μm*0.9mm. This corresponds to the pitch of 4 pixel columns, each one is 20μm wide

A low power and low signal 4 bit 50MS/s double sampling pipelined ADC for Monolithic Active Pixel Sensors

soumis à JINSTA 4 bit very low power and low incoming signal analog to digital converter (ADC) using a double sampling switched capacitor technique, designed for use in CMOS monolithic active pixels sensor readout, has been implemented in 0.35µm CMOS technology. A non-resetting sample and hold stage is integrated to amplify the incoming signal by 4. This first stage compensates both the amplifier offset effect and the input common mode voltage fluctuations. The converter is composed of a 2.5 bit pipeline stage followed by a 2 bit flash stage. This prototype consists of 4 ADC double-channels; each one is sampling at 50MS/s and dissipates only 2.6mW at 3.3V supply voltage. A bias pulsing stage is integrated in the circuit. Therefore, the analog part is switched OFF or ON in less than 1µs. The size for the layout is 80µm*0.9mm. This corresponds to the pitch of 4 pixel columns, each one is 20µm wide

Art therapy, arts-based research and transitional stories of domestic violence and abuse

Visual imagery within qualitative research is an established method of gathering data that has parallels to the way in which images are used within art therapy. This paper explores how visual imagery was used to investigate women’s responses to domestic violence and abuse and examines how art therapy principles shaped the development and conducting of that research. Through the use of collage, participants created visual representations of their responses to experiences of domestic violence and abuse. The visual representations were, when combined with spoken words, created stories that reference the past, present and future. The stories created have been termed transitional stories of domestic violence. These stories show that the home has special significance for women as they transition away from domestic violence and plan for their future. The home becomes both a metaphorical and physical manifestation and container of hopes for a harmonious future that often incorporates the desire for the return to the idea of a complete family. This paper will present the findings of the arts-based research conducted, and consider the implications upon art therapy practice of those findings.N

Feasibility of a cohort study on health risks caused by occupational exposure to radiofrequency electromagnetic fields

Breckenkamp J, Berg-Beckhoff G, Muenster E, et al. Feasibility of a cohort study on health risks caused by occupational exposure to radiofrequency electromagnetic fields. Environmental Health. 2009;8(1):23.Background: The aim of this study was to examine the feasibility of performing a cohort study on health risks from occupational exposure to radiofrequency electromagnetic fields (RF-EMF) in Germany. Methods: A set of criteria was developed to evaluate the feasibility of such a cohort study. The criteria aimed at conditions of exposure and exposure assessment (level, duration, preferably on an individual basis), the possibility to assemble a cohort and the feasibility of ascertaining various disease endpoints. Results: Twenty occupational settings with workers potentially exposed to RF-EMF and, in addition, a cohort of amateur radio operators were considered. Based on expert ratings, literature reviews and our set of predefined criteria, three of the cohorts were identified as promising for further evaluation: the personnel (technicians) of medium/short wave broadcasting stations, amateur radio operators, and workers on dielectric heat sealers. After further analyses, the cohort of workers on dielectric heat sealers seems not to be feasible due to the small number of exposed workers available and to the difficulty of assessing exposure (exposure depends heavily on the respective working process and mixture of exposures, e.g. plastic vapours), although exposure was highest in this occupational setting. The advantage of the cohort of amateur radio operators was the large number of persons it includes, while the advantage of the cohort of personnel working at broadcasting stations was the quality of retrospective exposure assessment. However, in the cohort of amateur radio operators the exposure assessment was limited, and the cohort of technicians was hampered by the small number of persons working in this profession. Conclusion: The majority of occupational groups exposed to RF-EMF are not practicable for setting up an occupational cohort study due to the small numbers of exposed subjects or due to exposure levels being only marginally higher than those of the general public

Air pollution and lung function among susceptible adult subjects: a panel study

BACKGROUND: Adverse health effects at relatively low levels of ambient air pollution have consistently been reported in the last years. We conducted a time-series panel study of subjects with chronic obstructive pulmonary disease (COPD), asthma, and ischemic heart disease (IHD) to evaluate whether daily levels of air pollutants have a measurable impact on the lung function of adult subjects with pre-existing lung or heart diseases. METHODS: Twenty-nine patients with COPD, asthma, or IHD underwent repeated lung function tests by supervised spirometry in two one-month surveys. Daily samples of coarse (PM(10–2.5)) and fine (PM(2.5)) particulate matter were collected by means of dichotomous samplers, and the dust was gravimetrically analyzed. The particulate content of selected metals (cadmium, chrome, iron, nickel, lead, platinum, vanadium, and zinc) was determined by atomic absorption spectrometry. Ambient concentrations of nitrogen dioxide (NO(2)), carbon monoxide (CO), ozone (O(3)), and sulphur dioxide (SO(2)) were obtained from the regional air-quality monitoring network. The relationships between concentrations of air pollutants and lung function parameters were analyzed by generalized estimating equations (GEE) for panel data. RESULTS: Decrements in lung function indices (FVC and/or FEV(1)) associated with increasing concentrations of PM(2.5), NO(2 )and some metals (especially zinc and iron) were observed in COPD cases. Among the asthmatics, NO(2 )was associated with a decrease in FEV(1). No association between average ambient concentrations of any air pollutant and lung function was observed among IHD cases. CONCLUSION: This study suggests that the short-term negative impact of exposure to air pollutants on respiratory volume and flow is limited to individuals with already impaired respiratory function. The fine fraction of ambient PM seems responsible for the observed effects among COPD cases, with zinc and iron having a potential role via oxidative stress. The respiratory function of the relatively young and mild asthmatics included in this study seems to worsen when ambient levels of NO(2 )increase

Health effects of ambient air pollution – recent research development and contemporary methodological challenges

Exposure to high levels of air pollution can cause a variety of adverse health outcomes. Air quality in developed countries has been generally improved over the last three decades. However, many recent epidemiological studies have consistently shown positive associations between low-level exposure to air pollution and health outcomes. Thus, adverse health effects of air pollution, even at relatively low levels, remain a public concern. This paper aims to provide an overview of recent research development and contemporary methodological challenges in this field and to identify future research directions for air pollution epidemiological studies