181 research outputs found

    CCD/CMOS Sensors Introduction Articles

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    CCD/CMOS Sensors Introduction Articles

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    Data Sheets on Sensors and Amplifiers

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    Data Sheets on Sensors and Amplifiers

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    A Current-Mode Position Sensitive Circuit

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    A novel technique to implement mesh-type position sensitive devices using current-mode analog VLSI is presented. By taking advantage of local analog computation this approach allows to create extremely compact circuit implementations. While in conventional approaches most sensor characteristics are adjusted by setting process parameters, our technique is fully electronically tunable and suitable to be implemented in general purpose CMOS technology. We have verified experimentally our idea designing and fabricating via MOSIS a 20 element 1D position circuit. Test results are presented demonstrating nonlinearity below 2.2% for currents in the range of 5pA to 10nA

    Fast and Reliable Modeling of Piezoelectric Transducers for Energy Harvesting Applications

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    The paper presents a fast and reliable model identification technique for piezoelectric transducers based on an equivalent electromechanical circuit easily implementable on SPICE-like simulation tools. Model parameter extraction is simple and requires just standard and inexpensive laboratory equipment. Indeed, the equivalent circuit representation permits the evaluation of the response of a real energy harvesting system, where the electronic load is a synchronized switching converter which usually causes a significant feedback on the mechanical part of the system during energy extraction. Both simulation and measurements show that the damping effect is particularly important near resonance, where the adopted model is able to fit the experimental data and provides a more realistic description of the behavior of the system

    A 32 mV/69 mV input voltage booster based on a piezoelectric transformer for energy harvesting applications

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    This paper presents a novel method for battery-less circuit start-up from ultra-low voltage energy harvesting sources. The approach proposes for the first time the use of a Piezoelectric Transformer (PT) as the key component of a step-up oscillator. The proposed oscillator circuit is first modelled from a theoretical point of view and then validated experimentally with a commercial PT. The minimum achieved start-up voltage is about 69 mV, with no need for any external magnetic component. Hence, the presented system is compatible with the typical output voltages of thermoelectric generators (TEGs). Oscillation is achieved through a positive feedback coupling the PT with an inverter stage made up of JFETs. All the used components are in perspective compatible with microelectronic and MEMS technologies. In addition, in case the use of a ∼40 μH inductor is acceptable, the minimum start-up voltage becomes as low as about 32 mV

    Diffusion networks for on-chip image contrast normalization

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    A new method for normalizing and quantizing images is presented. The method is based on calculating a local reference frame for the image gray levels. The levels of the reference frame are calculated using biased diffusions that are linked to the original image. The method is conceived to be integrated with sensing elements on the image plane of a camera. Its mathematical properties are analyzed and its performance is experimentally demonstrated. A circuital implementation has been designed, constructed and tested; it consists of a 20 nodes 1-D non-linear resistive grid. Experimental results are shown

    A Current-Mode Position Sensitive Circuit

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    A novel technique to implement mesh-type position sensitive devices using current-mode analog VLSI is presented. By taking advantage of local analog computation this approach allows to create extremely compact circuit implementations. While in conventional approaches most sensor characteristics are adjusted by setting process parameters, our technique is fully electronically tunable and suitable to be implemented in general purpose CMOS technology. We have verified experimentally our idea designing and fabricating via MOSIS a 20 element 1D position circuit. Test results are presented demonstrating nonlinearity below 2.2% for currents in the range of 5pA to 10nA

    Design of low-voltage integrated step-up oscillators with microtransformers for energy harvesting applications

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    This paper describes the modeling of startup circuits in battery-less micropower energy harvesting systems and investigates the use of bond wire micromagnetics. The analysis focuses on step-up Meissner oscillators based on magnetic core transformers operating with input voltages down to ≈100 mV, e.g. from thermoelectric generators. As a key point, this paper examines the effect of core losses and leakage inductances on the startup requirements obtained with the classical Barkhausen criterion, and demonstrates the minimum transconductance for oscillations to occur. For validation purposes, a step-up oscillator IC is fabricated in a STMicroelectronics 0.32 μm technology, and connected to two bond-wire microtransformers, respectively, with a 1:38 MnZn ferrite core and with a 1:52 ferromagnetic low-temperature co-fired ceramic (LTCC) core. Coherently with the proposed model, experimental measurements show a minimum startup voltage of 228 mV for the MnZn ferrite core and of 104 mV for the LTCC core
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