Open Access
Pseudo-three-stage Miller op-amp with enhanced small-signal and large-signal performance
(IEEE, 2019) Paul, Anindita; Ramírez-Angulo, Jaime; López Martín, Antonio; González Carvajal, Ramón; Rocha-Pérez, José Miguel; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
A simple technique to implement highly power efficient class AB-AB Miller op-amps is presented in this paper. It uses a composite input stage with resistive local common mode feedback that provides class AB operation to the input stage and essentially enhances the op-amp's effective transconductance gain, the dc open-loop gain, the gain-bandwidth product, and slew rate with just moderate increase in power dissipation. The experimental results of op-amps in strong inversion and subthreshold fabricated in a 130-nm standard CMOS technology validate the proposed approach. The op-amp has 9 V·pF/μs·μW large-signal figure of merit (FOM) and 17 MHz · pF/μW small-signal FOM with 1.2-V supply voltage. In subthreshold, the op-amp has 10 V · pF/μs · μW large-signal FOM and 92 MHz · pF/μW small-signal FOM with 0.5-V supply voltage.
Open Access
Design of low-cost smart accelerometers
(Universitat Politècnica de Catalunya, 2005) Carlosena García, Alfonso; López Martín, Antonio; Massarotto, Marco; Cruz Blas, Carlos Aristóteles de la; Lecumberri Villamediana, Pablo; Gómez Fernández, Marisol; Pintor Borobia, Jesús María; Gárriz Sanz, Sergio; Ingeniería Eléctrica y Electrónica; Matemáticas; Ingeniería Mecánica, Energética y de Materiales; Ingeniaritza Elektrikoa eta Elektronikoa; Matematika; Mekanika, Energetika eta Materialen Ingeniaritza
The goal of this project is to design a low-cost smart accelerometer, making use of a piezoelectric element as basic sensing material, and adding a mixed-mode conditioning circuit.
Open Access
Enhanced single-stage folded cascode OTA suitable for large capacitive loads
(IEEE, 2018) López Martín, Antonio; Garde Luque, María Pilar; Algueta-Miguel, Jose M.; Cruz Blas, Carlos Aristóteles de la; Carvajal, Ramón G.; Ramírez-Angulo, Jaime; Institute of Smart Cities - ISC
An enhanced single-stage folded cascode operational transconductance amplifier able to drive large capacitive loads is presented. Circuits that adaptively bias the input differential pair and the current folding stage are employed, which provide class AB operation with dynamic current boosting and increased gainbandwidth (GBW) product. Measurement results of a test chip prototype fabricated in a 0.5-µm CMOS process show an increase in slew rate and GBW by a factor of 30 and 15, respectively, versus the class A version using the same supply voltage and bias currents. Overhead in other performance metrics is small.
Open Access
Design of MOS-translinear multiplier/dividers in analog VLSI
(Hindawi Publishing Corporation, 2000) López Martín, Antonio; Carlosena García, Alfonso; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
A general framework for designing current-mode CMOS analog multiplier/divider circuits based on the cascade connection of a geometric-mean circuit and a squarer/ divider is presented. It is shown how both building blocks can be readily obtained from a generic second-order MOS translinear loop. Various implementations are proposed, featuring simplicity, favorable precision and wide dynamic range. They can be successfully employed in a wide range of analog VLSI processing tasks. Experimental results of two versions, based on stacked and folded MOS-translinear loops and fabricated in a 2.4-1am CMOS process, are provided in order to verify the correctness of the proposed approach.
Open Access
Buscando claves para promover la participación de la mujer en estudios de Ingeniería de Telecomunicación
(Educación Editora, 2014) Alejos, Ana V.; Milagros, María Pilar; Falcone Lanas, Francisco; López Martín, Antonio; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza
En la presente contribución se discute la necesidad de analizar el problema de la escasa presencia de la mujer en los estudios de Ingeniería de Telecomunicación. Se describe una encuesta en curso para indagar los factores de la segregación de género en esta carrera. Asimismo, se propone trasladar al aula medidas que capten una mayor presencia femenina.
Open Access
Super class AB RFC OTA with adaptive local common-mode feedback
(Institution of Engineering and Technology, 2018) Garde Luque, María Pilar; López Martín, Antonio; Carvajal, Ramón G.; Ramírez-Angulo, Jaime; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
A super class AB recycling folded cascode operational transconductance amplifier is presented. It employs local common-mode feedback using two matched tuneable active resistors, allowing to adapt the amplifier to different process variations and loads. Measurement results from a test chip prototype fabricated in a 0.5 μm CMOS process validate the proposal.
Open Access
Super class AB RFC OTA using non-linear current mirrors
(Institution of Engineering and Technology, 2018) Garde Luque, María Pilar; López Martín, Antonio; Carvajal, Ramón G.; Galán, J.A.; Ramírez-Angulo, Jaime; Institute of Smart Cities - ISC
An alternative approach to the design of super class AB recycling folded cascode operational transconductance amplifiers is proposed. Instead of using local common-mode feedback for boosting dynamic currents, simple current mirrors with input transistors entering triode region for large currents are employed. Measurement results from a 0.5 μm CMOS test chip validate the proposal.
Open Access
Low-power ultrasonic front-end for cargo container monitoring
(IEEE, 2019) Algueta-Miguel, Jose M.; García Oya, José Ramón; López Martín, Antonio; Cruz Blas, Carlos Aristóteles de la; Muñoz Chavero, Fernando; Hidalgo Fort, Eduardo; Institute of Smart Cities - ISC
A low-power ultrasonic communication system conceived for cargo container monitoring is presented. Two piezoelectric transducers operating at 40 kHz are used for generating and acquiring an ultrasonic signal through the metallic wall, thus establishing a non-invasive inside-outside communication that preserves the container integrity. Both transducers are fixed by means of a novel magnetic case designed for optimizing data transmission. The acoustic and electrical characteristics of the ultrasonic channel are analyzed. An experimental measurement setup based on FPGA has been implemented for comparing some basic modulation and detection schemes in terms of Bit Error Rate (BER), also considering their robustness against undesired mechanical and electromagnetic perturbations. On this basis, a compact digital DBPSK modulator using a square carrier signal is proposed. Frequency and amplitude tracking algorithms are designed for optimizing the quality and robustness of the data transmission. Finally, a low-power low-rate (up to few kbps) architecture based on the previous elements is presented. All the proposed contributions are experimentally validated.
Open Access
Sensing in coin discriminators
(IEEE, 2007) Carlosena García, Alfonso; López Martín, Antonio; Arizti, Fernando; Martínez de Guereñu, Ane; Pina Insausti, José L.; García Sayés, Miguel; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
This paper describes the technologies used in coin discriminator devices, stressing the improvements and novel mechanisms introduced by the authors in the past few years as a result of the cooperation with one leading company in the vending sector. Emphasis is put on how low-cost sensors are used to characterize coins (or tokens) and discriminate them from their counterfeits.
Open Access
Energy harvesting approaches in IoT scenarios with very low ambient energy
(European Association for the Development of Renewable Energy, Environment and Power Quality (EA4EPQ), 2019) López Martín, Antonio; Algueta-Miguel, Jose M.; Matías Maestro, Ignacio; Institute of Smart Cities - ISC
The feasibility of multi-source energy harvesting in Internet of Things (IoT) scenarios with low and intermittent ambient energy is addressed. As a relevant case study, application to a smart cargo container system is analysed. The most relevant features of the main energy sources available in this target application are identified, and various transducers adapted to such sources are evaluated. Measurement results indicate that combined piezoelectric and thermoelectric generation inside cargo containers can significantly extend the battery lifetime of IoT end nodes embedded in such containers.