Desfasador sintonizable CMOS para aplicaciones de sintonía automática

En este artículo se presenta el diseño e implementación de un desfasador con capacidad de sintonía mediante una tensión de control externa, que ofrece un desfase de π/2 a una frecuencia específica de interés. La utilización de resistencias negativas, y su fácil implementación mediante el bloque circuital conocido como MRC (MOS Resistive Circuit) simplifica notablemente el diseño y realización del mismo. Los resultados experimentales obtenidos y expuestos para una tecnología CMOS de 0,8 μm validan la funcionalidad del circuito.Postprint (published version

Diseño e implementación de un filtro MRC-C con sintonía automática on-chip

En el presente artículo se describe el diseño e implementación de los lazos de sintonía (tanto del que fija la frecuencia central como del que fija el factor de calidad) de un filtro pasa-banda de tiempo continuo fully-balanced para aplicaciones de audio basado en una modificación de la estructura TQE (Transimpedance Q-Enhacement). El circuito ha sido diseñado y fabricado en tecnología CMOS de 0,8 μm y se han utilizado células del tipo MRC (MOS Resistive Circuit) para poder implementar las resistencias sintonizables electrónicamente. Los resultados experimentales obtenidos para dicha tecnología validan la funcionalidad del circuito de sintonía.Postprint (published version

Design of Analog CMOS Circuits for Batteryless Implantable Telemetry Systems

A wireless biomedical telemetry system is a device that collects biomedical signal measurements and transmits data through wireless RF communication. Testing medical treatments often involves experimentation on small laboratory animals, such as genetically modified mice and rats. Using batteries as a power source results in many practical issues, such as increased size of the implant and limited operating lifetime. Wireless power harvesting for implantable biomedical devices removes the need for batteries integrated into the implant. This will reduce device size and remove the need for surgical replacement due to battery depletion. Resonant inductive coupling achieves wireless power transfer in a manner modelled by a step down transformer. With this methodology, power harvesting for an implantable device is realized with the use of a large primary coil external to the subject, and a smaller secondary coil integrated into the implant. The signal received from the secondary coil must be regulated to provide a stable direct current (DC) power supply, which will be used to power the electronics in the implantable device. The focus of this work is on development of an electronic front-end for wireless powering of an implantable biomedical device. The energy harvesting front-end circuit is comprised of a rectifier, LDO regulator, and a temperature insensitive voltage reference. Physical design of the front-end circuit is developed in 0.13um CMOS technology with careful attention to analog layout issues. Post-layout simulation results are presented for each sub-block as well as the full front-end structure. The LDO regulator operates with supply voltages in the range of 1V to 1.5V with quiescent current of 10.5uA The complete power receiver front-end has a power conversion efficiency of up to 29%

NASA Space Engineering Research Center for VLSI System Design

This annual report outlines the activities of the past year at the NASA SERC on VLSI Design. Highlights for this year include the following: a significant breakthrough was achieved in utilizing commercial IC foundries for producing flight electronics; the first two flight qualified chips were designed, fabricated, and tested and are now being delivered into NASA flight systems; and a new technology transfer mechanism has been established to transfer VLSI advances into NASA and commercial systems

Calculations of Vacancy Diffusivity in WO3

The memristor is viewed as a promising material to store digital information and has analog applications that drew researchers’ attention. Researchers explored the possibilities of using memristors to simulate synapses in the human brain. WO3 is one of the materials that can make memristors. Based on the mechanism of memristors, we know the motion of defects in WO3 changes the Schottky barrier and the current; thus, it can make the switch between high resistance state, HRS, and low resistance state, LRS. This paper will explore vacancy diffusivity in WO3. In this research, we concentrate on the cubic and monoclinic structure of WO3. We use the first principle density functional theory or DFT, and hybrid DFT to calculate the formation energy of different charge states of oxygen vacancies in WO3 and plot the graph of Fermi level to find the charge state with the lowest formation energy conditions. We use the nudged elastic band method to get the energy barrier for the vacancies to migrate inside the structure

Multipath feedforward compensated amplifier, related dipole (doublet) compression technique, and other topics

In order to truly realize entire mixed-signal systems on a chip and leverage the benefits of advanced process technologies, new low-voltage compatible amplifier topologies need to be developed.;In this context, a multipath-compensated multistage amplifier is introduced. These structures are compatible with low-voltage supplies because they use horizontal techniques (cascading) rather than vertical techniques (device stacking) to achieve large DC gains. When properly designed, these amplifiers are inherently first-order and do not suffer a reduction in the achievable gain-bandwidth product due to the process of compensation.;The technique relies upon pole-zero cancellation for proper operation. Absent techniques that ensure accurate cancellations, these architectures are not practical for high-speed applications. This is due to the fact that imperfect cancellations result in the appearance of slow-settling components in the transient response. To overcome this problem, structures that inherently ensure accurate cancellation or those that tune themselves to compensate for variations need to be developed.;A tuning strategy for a two-stage multipath-compensated amplifier was developed. It is based upon the observation that if the low-frequency pole leads the zero, the step-response is underdamped. Conversely, if the zero leads the pole, it is overdamped. By sensing the slope of the transient step response after a delay, the relationship between the location of the pole and the zero can be determined. Utilizing this information, a bias current is adjusted to modify the pole\u27s location relative to the zero. The process is repeated many times driving the mismatch down to an acceptable level. The concept was experimentally verified using a prototype fabricated in a 0.25mu CMOS process.;The insight gained in developing a tuning strategy for the two-stage amplifier has led to a methodology for tuning an amplifier with three or more stages. Preliminary simulations predict the technique is viable.;The thesis covers two additional topics as well. The first is a new CAD tool that enables designers to quickly understand the available design tradeoffs by interactive design space exploration. The second topic is a new transresistor circuit whose linearity is comparable to existing transresistors yet offers realizations that are simpler and more compact.*;*This dissertation is a compound document (contains both a paper copy and a CD as part of the dissertation). The CD requires the following system requirements: Adobe Acrobat; Microsoft Office; Windows MediaPlayer or RealPlayer; Internet browser; WinZip

State-of-the-Art Sensors Technology in Spain 2015: Volume 1

This book provides a comprehensive overview of state-of-the-art sensors technology in specific leading areas. Industrial researchers, engineers and professionals can find information on the most advanced technologies and developments, together with data processing. Further research covers specific devices and technologies that capture and distribute data to be processed by applying dedicated techniques or procedures, which is where sensors play the most important role. The book provides insights and solutions for different problems covering a broad spectrum of possibilities, thanks to a set of applications and solutions based on sensory technologies. Topics include: • Signal analysis for spectral power • 3D precise measurements • Electromagnetic propagation • Drugs detection • e-health environments based on social sensor networks • Robots in wireless environments, navigation, teleoperation, object grasping, demining • Wireless sensor networks • Industrial IoT • Insights in smart cities • Voice recognition • FPGA interfaces • Flight mill device for measurements on insects • Optical systems: UV, LEDs, lasers, fiber optics • Machine vision • Power dissipation • Liquid level in fuel tanks • Parabolic solar tracker • Force sensors • Control for a twin roto

Measurements, Models, Systems and Design

531 s.

The Fifth NASA Symposium on VLSI Design

The fifth annual NASA Symposium on VLSI Design had 13 sessions including Radiation Effects, Architectures, Mixed Signal, Design Techniques, Fault Testing, Synthesis, Signal Processing, and other Featured Presentations. The symposium provides insights into developments in VLSI and digital systems which can be used to increase data systems performance. The presentations share insights into next generation advances that will serve as a basis for future VLSI design