¿Cómo mejorar la docencia en electrónica de dispositivos? Guía de actividades

La implementación de un Ciclo de Mejora Docente (CDM) se ha realizado en la asignatura “Electrónica Física”. La asignatura es el primer contacto de los estudiantes con el estudio de la física de los dispositivos semiconductores, siendo muchos de los conceptos impartidos totalmente novedosos para el alumnado. El índice de aprobados de la asignatura ha sido tradicionalmente bajo, aun cuando la nota de corte de algunas de las titulaciones de los alumnos que la cursan es muy alta. El ciclo de mejora se apoya en la elaboración de guía de actividades y boletines de problemas que se adaptan a las necesidades del alumnado, actuando el profesor como guía en la resolución de los problemas planteados

What are the substitutes of the current transistors? Debate and supervised study activities in Electronics of Devices

La presente comunicación resume los resultados obtenidos tras la implementación de un Ciclo de Mejora en el Aula (CIMA) de la asignatura de Dispositivos y Tecnologías Micro y Nanométricos impartida en el Máster de Microelectrónica de la Universidad de Sevilla durante el curso 2021-2022. Como novedad, se propuso que los alumnos hicieran búsquedas en un portal especializado sobre dispositivos semiconductores emergentes, con el fin de que este material fuera objeto de estudio y debate en clases posteriores. Los resultados de la innovación docente indican que los alumnos se sienten más motivados y obtienen mejores resultados al ser ellos mismos los que generan su material de estudio. En paralelo, las actividades de debate contribuyen a mejorar su exposición oral en público, lo cual les beneficia a corto y largo plazo.This communication summarizes the results obtained after the implementation of a Cycle of Improvement in the Classroom for the subject Devices and Micro and Nanotechnologies of the Master in Microelectronics of the University of Seville during the academic year 2021-2022. As a novelty, the students had to seek the teaching material about emerging electronic devices on a specialized portal on the matter. This study material was used afterward by the students to study the subject and to organize debate activities in the classroom. The results of the teaching experience suggest that the students are more motivated and get better results when they prepare themselves the study material. Moreover, debate activities contribute to improving their oral presentation skills, which is beneficial for them in the short and the long terms

A high dynamic range image sensor with linear response based on asynchronous event detection

This paper investigates the potential of an image sensor that combines event-based asynchronous outputs with conventional integration of photocurrents. Pixels voltages can be read out following a traditional approach with a source follower and analog-to-digital converter. Furthermore, pixels have circuitry to implement Pulse Density Modulation (PDM) sending out pulses with a frequency that is proportional to the photocurrent. Both read-out approaches operate simultaneously. Their information is combined to render high dynamic range images. In this paper, we explain the new vision sensor concept and we develop a theoretical analysis of the expected performance in standard AMS 0.18mm HV technology. Moreover, we provide a description of the vision sensor architecture and its main blocksMinisterio de Economía, Industria y Competitividad TEC2012-38921-C02-02European Union IPT-2011-1625-430000Office of Naval Research (USA) N00014-14-1-035

Real-time phase correlation based integrated system for seizure detection

This paper reports a low area, low power, integer-based digital processor for the calculation of phase synchronization between two neural signals. The processor calculates the phase-frequency content of a signal by identifying the specific time periods associated with two consecutive minima. The simplicity of this phase-frequency content identifier allows for the digital processor to utilize only basic digital blocks, such as registers, counters, adders and subtractors, without incorporating any complex multiplication and or division algorithms. In fact, the processor, fabricated in a 0.18μm CMOS process, only occupies an area of 0.0625μm2 and consumes 12.5nW from a 1.2V supply voltage when operated at 128kHz. These low-area, low-power features make the proposed processor a valuable computing element in closed loop neural prosthesis for the treatment of neural diseases, such as epilepsy, or for extracting functional connectivity maps between different recording sites in the brain.Ministerio de Economía y Competitividad TEC2016- 80923-

A bioinspired 128x128 pixel dynamic-vision-sensor

This paper presents a 128x128 dynamic vision sensor. Each pixel detects temporal changes in the local illumination. A minimum illumination temporal contrast of 10% can be detected. A compact preamplification stage has been introduced that allows to improve the minimum detectable contrast over previous designs, while at the same time reducing the pixel area by 1/3. The pixel responds to illumination changes in less than 3.6μs. The ability of the sensor to capture very fast moving objects has been verified experimentally. A frame-based sensor capable to achieve this, would require at least 100K frames per second.Unión Europea FP7-ICT-2007-1-216777Ministerio de Educación y Ciencia TEC2006-11730-C03-01 (SAMANTA2)Ministerio de Educación y Ciencia TEC2009-10639- C04-01 (VULCANO)Junta de Andalucía P06- TIC-1417 (Brain System

Pipeline AER arbitration with event aging

We present a simple circuit to handle communication between cells of neuromorphic arrays. It allows cells to operate continuously without waiting for acknowledgement signals back from the AER (Address Event Representation) arbitration circuitry. The module also implements aging of cell petitions i.e., old petitions to access to the AER bus are automatically discarded to give priority to the more recent ones and alleviate the bus congestion. The new arbitration scheme has been implemented and tested. A particular application scenario with an image sensor with spiking pixels that sense light continuously is explained. The sensing errors per event due to discontinued pixel operation can be minimized a factor 8.1. Experimental data obtained with real visual scenes are provided.Universidad de Cádiz PR2016-072Ministerio de Economía y Competitividad TEC2015-66878- C3-1-RJunta de Andalucía TIC 2012-2338Office of Naval Research (USA) N00014141035

A Bio-Inspired Vision Sensor With Dual Operation and Readout Modes

This paper presents a novel event-based vision sensor with two operation modes: intensity mode and spatial contrast detection. They can be combined with two different readout approaches: pulse density modulation and time-to-first spike. The sensor is conceived to be a node of an smart camera network made up of several independent an autonomous nodes that send information to a central one. The user can toggle the operation and the readout modes with two control bits. The sensor has low latency (below 1 ms under average illumination conditions), low power consumption (19 mA), and reduced data flow, when detecting spatial contrast. A new approach to compute the spatial contrast based on inter-pixel event communication less prone to mismatch effects than diffusive networks is proposed. The sensor was fabricated in the standard AMS4M2P 0.35-um process. A detailed system-level description and experimental results are provided.Office of Naval Research (USA) N00014-14-1-0355Ministerio de Economía y Competitividad TEC2012- 38921-C02-02, P12-TIC-2338, IPT-2011-1625-43000

A Wide Linear Dynamic Range Image Sensor Based on Asynchronous Self-Reset and Tagging of Saturation Events

We report a high dynamic range (HDR) image sensor with a linear response that overcomes some of the limitations of sensors with pixels with self-reset operation. It operates similar to an active pixel sensor, but its pixels have a novel asynchronous event-based overflow detection mechanism. Whenever the pixel voltages at the integration capacitance reach a programmable threshold, the pixels self-reset and send out asynchronously an event indicating this. At the end of the integration period, the voltage at the integration capacitance is digitized and readout. Combining this information with the number of events fired by each pixel, it is possible to render linear HDR images. Event operation is transparent to the final user. There is no limitation for the number of self-resets of each pixel. The output data format is compatible with frame-based devices. The sensor was fabricated in the AMS 0.18- μm HV technology. A detailed system description and experimental results are provided in this paper. The sensor can render images with an intra-scene dynamic range of up to 130 dB with linear outputs. The pixels' pitch is 25 μm and the sensor power consumption is 58.6 mW.Universidad de Cádiz PR2016-072Ministerio de Economía y Competitividad TEC2015-66878-C3-1-RJunta de Andalucía TIC 2012-2338Office of Naval Research (USA) N00014141035

Review of ADCs for imaging

The aim of this article is to guide image sensors designers to optimize the analog-to-digital conversion of pixel outputs. The most common ADCs topologies for image sensors are presented and discussed. The ADCs specific requirements for these sensors are analyzed and quantified. Finally, we present relevant recent contributions of specific ADCs for image sensors and we compare them using a novel FOM

Enhanced Sensitivity of CMOS Image Sensors by Stacked Diodes

We have investigated and compared the performance of photodiodes built with stacked p/n junctions operating in parallel versus conventional ones made with single p/n junctions. We propose a method to characterize and compare photodiodes sensitivity. For this purpose, a dedicated chip in the standard AMS 180-nm HV technology has been fabricated. Four different sensor structures were implemented and compared. Experimental results are provided. Measurements show sensitivity enhancement ranging from 55% to 70% within the 500-1100 nm spectral region. The larger increment is happening in the near infrared band (up to 62%). Such results make stacked photodiodes suitable candidates for the implementation of photosensors in vision chips designed for standard CMOS technologies.Ministerio de Economía y Competitividad TEC2012-33634, TEC2015-66878- C3-1-RJunta de Andalucía TIC 2012-2338Office of Naval Research (USA) N00014141035