Browsing by Author "Alvarez Fontecilla, Enrique"

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    Digital assistance for energy reduction in ADCs using a simple signal prediction algorithm
    (IEEE, 2014) Avila, Diego; Alvarez Fontecilla, Enrique; Abusleme Hoffman, Ángel Christian
    With the adoption of new technology nodes q for analog circuits, different digital techniques have been designed to enhance their performance. Among the existing techniques, a promising approach is to adapt the circuit operation dynamically considering the application characteristics. In the field of analog-to-digital converters (ADCs), typically this approach is carried out by taking advantage of application-dependent signal properties, hence their use is limited. In this work, a digital assistance technique for power reduction in ADCs is presented. By defining a reduced valid range for the next sample based upon the maximum possible change of the input signal between samples, the proposed algorithm reduces the mean energy consumption per conversion in a variety of ADC architectures, regardless of the application.
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    Noise in Charge Amplifiers—A gm/ID Approach
    (2012) Alvarez Fontecilla, Enrique; Ávila Gárate, Diego; Campillo Mecklenburg, Hernan; Dragone, A.; Abusleme Hoffman, Ángel Christian
    Charge amplifiers represent the standard solution to amplify signals from capacitive detectors in high energy physics experiments. In a typical front-end, the noise due to the charge amplifier, and particularly from its input transistor, limits the achievable resolution. The classic approach to attenuate noise effects in MOSFET charge amplifiers is to use the maximum power available, to use a minimum-length input device, and to establish the input transistor width in order to achieve the optimal capacitive matching at the input node. These conclusions, reached by analysis based on simple noise models, lead to sub-optimal results. In this work, a new approach on noise analysis for charge amplifiers based on an extension of the gm/ID methodology is presented. This method combines circuit equations and results from SPICE simulations, both valid for all operation regions and including all noise sources. The method, which allows to find the optimal operation point of the charge amplifier input device for maximum resolution, shows that the minimum device length is not necessarily the optimal, that flicker noise is responsible for the non-monotonic noise versus current function, and provides a deeper insight on the noise limits mechanism from an alternative and more design-oriented point of view.