Low-power transceiver design for mobile wireless chemical biological sensors

The design of a smart integrated chemical sensor system that will enhance sensor performance and compatibility to Ad hoc network architecture remains a challenge. This work involves the design of a Transceiver for a mobile chemical sensor. The transceiver design integrates all building blocks on-chip, including a low-noise amplifier with an input-matching network, a Voltage Controlled Oscillator with injection locking, Gilbert cell mixers, and a Class E Power amplifier making it as a single-chip transceiver. This proposed low power 2GHz transceiver has been designed in TSMC 0.35~lm CMOS process using Cadence electronic design automation tools. Post layout HSPICE simulation indicates that Design meets the separation of noise levels by 52dB and 42dB in transmitter and receiver respectively with power consumption of 56 mW and 38 mW in transmit and receive mode

Superharmonic Injection Locked Quadrature LC VCO Using Current Recycling Architecture

Quadrature LO signal is a key element in many of the RF transceivers which tend to dominate today’s wireless communication technology. The design of a quadrature LC VCO with better phase noise and lower power consumption forms the core of this work. This thesis investigates a coupling mechanism to implement a quadrature voltage controlled oscillator using indirect injection method. The coupling network in this QVCO couples the two LC cores with their super-harmonic and it recycles its bias current back into the LC tank such that the power consumed by the coupling network is insignificant. This recycled current enables the oscillator to achieve higher amplitude of oscillation for the same power consumption compared to conventional design, hence assuring better phase noise. Mathematical analysis has been done to study the mechanism of quadrature operation and mismatch effects of devices on the quadrature phase error of the proposed QVCO. The proposed quadrature LC VCO is designed in TSMC 0.18 μm technology. It is tunable from 2.61 GHz - 2.85 GHz with sensitivity of 240 MHz/V. Its worst case phase noise is -120 dBc/Hz at 1 MHz offset. The total layout area is 1.41 mm^2 and the QVCO core totally draws 3 mA current from 1.8 V supply

Analysis and design of sinusoidal quadrature RC-oscillators

Modern telecommunication equipment requires components that operate in many different frequency bands and support multiple communication standards, to cope with the growing demand for higher data rate. Also, a growing number of standards are adopting the use of spectrum efficient digital modulations, such as quadrature amplitude modulation (QAM) and orthogonal frequency division multiplexing (OFDM). These modulation schemes require accurate quadrature oscillators, which makes the quadrature oscillator a key block in modern radio frequency (RF) transceivers. The wide tuning range characteristics of inductorless quadrature oscillators make them natural candidates, despite their higher phase noise, in comparison with LC-oscillators. This thesis presents a detailed study of inductorless sinusoidal quadrature oscillators. Three quadrature oscillators are investigated: the active coupling RC-oscillator, the novel capacitive coupling RCoscillator, and the two-integrator oscillator. The thesis includes a detailed analysis of the Van der Pol oscillator (VDPO). This is used as a base model oscillator for the analysis of the coupled oscillators. Hence, the three oscillators are approximated by the VDPO. From the nonlinear Van der Pol equations, the oscillators’ key parameters are obtained. It is analysed first the case without component mismatches and then the case with mismatches. The research is focused on determining the impact of the components’ mismatches on the oscillator key parameters: frequency, amplitude-, and quadrature-errors. Furthermore, the minimization of the errors by adjusting the circuit parameters is addressed. A novel quadrature RC-oscillator using capacitive coupling is proposed. The advantages of using the capacitive coupling are that it is noiseless, requires a small area, and has low power dissipation. The equations of the oscillation amplitude, frequency, quadrature-error, and amplitude mismatch are derived. The theoretical results are confirmed by simulation and by measurement of two prototypes fabricated in 130 nm standard complementary metal-oxide-semiconductor (CMOS) technology. The measurements reveal that the power increase due to the coupling is marginal, leading to a figure-of-merit of -154.8 dBc/Hz. These results are consistent with the noiseless feature of this coupling and are comparable to those of the best state-of-the-art RC-oscillators, in the GHz range, but with the lowest power consumption (about 9 mW). The results for the three oscillators show that the amplitude- and the quadrature-errors are proportional to the component mismatches and inversely proportional to the coupling strength. Thus, increasing the coupling strength decreases both the amplitude- and quadrature-errors. With proper coupling strength, a quadrature error below 1° and amplitude imbalance below 1% are obtained. Furthermore, the simulations show that increasing the coupling strength reduces the phase noise. Hence, there is no trade-off between phase noise and quadrature error. In the twointegrator oscillator study, it was found that the quadrature error can be eliminated by adjusting the transconductances to compensate the capacitance mismatch. However, to obtain outputs in perfect quadrature one must allow some amplitude error

Remote Monitoring of the Heart Condition of Athletes by Measuring the Cardiac Action Potential Propagation Time Using a Wireless Sensor Network

Highly performing athletes are susceptible to cardiac damage of several kinds which may be irreversible. The monitoring of heart rate and ECG waveforms from such subjects by wireless sensor networks has been reported in health and sports care documents. However, a more decisive parameter for instant to instant changes would be the time of Cardiac Action Potential Propagation. This time, which can be between 15-20 ms would shoot suddenly in acute stress in highly performing athletes for short durations. Repeated incidents of such rising values will tend to cause irreversible damage to the heart. We developed the technique of measuring this time and reporting it through a wireless sensor network to monitoring station

Synthétiseur de fréquences RF destiné aux dispositifs médicaux implantables

RÉSUMÉ Les microsystèmes biomédicaux implantables présentent un énorme potentiel pour la recherche médicale. Les dispositifs médicaux intelligents implantables, qui combinent des capteurs et/ou des actuateurs avec des circuits intégrés, ouvrent la voie à des applications fascinantes. Aujourd’hui, la possibilité d’utiliser la technologie CMOS pour intégrer des circuits RF, numériques, et même certains types de capteurs sur une même puce, suscite un vif intérêt dans un domaine nouveau : celui des réseaux de capteurs implantables, ou BSN (Body-Sensor Networks) et leurs applications en recherche biomédicale. L’implantation dans le corps de tels réseaux de capteurs sans-fils permettrait de surveiller, détecter ou même combattre différentes maladies, et ce de manière in situ. Avec des dimensions minimales inférieures à 100 nm, la technologie CMOS représente un choix viable pour l’implémentation des blocs de bases des circuits intégrés radio-fréquences (Radio- Frequency Integrated Circuits - RFIC) à faible consommation de puissance. Toutefois, la réduction de la tension d’alimentation permise dans les procédés CMOS nanométriques, l’impédance de sortie limitée des transistors disponibles, ainsi que les variations de procédés ont pour conséquence que plusieurs architectures de circuits analogiques n’offrent plus les performances requises ou ne sont tout simplement plus applicables. Des méthodes de conception innovatrices doivent être utilisées et des compromis judicieux doivent être faits afin de maintenir les performances requises. Dans un système de communication sans-fil, l’oscillateur local (Local Oscillator - LO) est l’un des modules les plus importants puisqu’il sert à générer la porteuse du lien RF qui sera par la suite modulée pour transmettre les données. Dans un contexte où la consommation de puissance doit être strictement minimisée, la génération d’une fréquence porteuse RF stable dans un procédé CMOS nanométrique présente des défis énormes. Dans cette optique, cette thèse se concentre sur la conception, l’analyse, ainsi que sur l’implémentation de circuits analogiques et RF à basse tension faisant partie d’un synthétiseur de fréquences à consommation ultra faible utilisant un procédé CMOS nanométrique. Tout d’abord, une nouvelle architecture de miroir de courant présentant une impédance de sortie très élevée destiné aux applications à faible tension d’alimentation est présentée. Ce miroir de courant de faible complexité présente une résistance de sortie très élevée et ce pour des tensions de sortie s’approchant des alimentations. Ensuite, une nouvelle architecture de pompe de charges CMOS destinée aux boucles à verrouillage de phase à faible tension et faible puissance est proposée afin de contourner les difficultés causées par la basse tension d’alimentation et la faible impédance de sortie des transistors nanométriques.----------ABSTRACT Implantable biomedical microsystems present a huge potential for medical research. The recent possibility to use CMOS technology to integrate radio-frequency (RF) circuits, baseband signal processing, and even sensors on a same chip has led to a tremendous growth of interest in wireless sensors and their applications. Such microsystems typically include a microprocessor and memory, an energy source, one or more sensors, an analog-to-digital converter (ADC), and a RF transceiver to communicate with a remote base-station or processing unit. In the biomedical field, it is expected that implanting such wireless sensing microsystems could greatly help the medical research community in learning about the progression of some diseases and assess degree of response to treatment. With a minimum feature size that has reduced under 100 nm, CMOS technology has become a viable choice for the implementation of low-power radio-frequency integrated circuits (RFIC) building blocks. However, the reduction of the supply voltage combined with the low output impedance of nanometer transistors have caused many analog and RF circuit solutions to be unsuitable, or even unusable due to voltage headroom constraints. Therefore, new circuit techniques and innovative design approaches are needed in order to meet the required performance level while maintaining low power consumption. In a wireless communications system, the local oscillator (LO) is one of the most important building blocks since it generates the RF carrier signal upon which data is modulated for transmission. In a context where power consumption must be strictly minimized, the generation of a stable RF carrier using a nanometer CMOS process presents huge challenges. In this regard, this thesis focuses on the design, the analysis and the implementation of low-voltage analog and RF circuits used to build an ultra-low power integer-N frequency synthesizer. First, a new current mirror architecture dedicated to low-voltage, low-power applications is presented. The proposed current mirror offers a very high output resistance and an enhanced output voltage range in comparison with other current mirrors similar in architecture. Then, a novel charge pump dedicated to low-power low-voltage PLLs is proposed. The design of this circuit was motivated by the need of a nano-CMOS charge pump that would offer constant current magnitude and minimum current mismatch over a wide range of output voltage, while maintaining power consumption and complexity level as low as possible. A LC resonator-based voltage-controlled oscillator (LC-VCO) that implements a new technique to reduce the impact of process variation on phase noise and power consumption is presented

Capacitance to voltage converter design for biosensor applications

Due to advances in MEMS fabrication, Lab-on-Chip (LoC) technology gained great progress. LoC refers to small chips that might do similar works to equipped laboratory. Miniaturization of laboratory platform results in low area, low sampleconsumption and less measurement time. Hence, LoC with IC integration finds numerous implementations in biomedical applications. Electrochemical biosensors are preferred for LoC applications because electrochemical biosensors can be easily integrated into IC designs due to electrode-based transducing. Capacitive biosensors are distinctive in electrochemical biosensors because of their reliability and sensitivity advantages. Therefore Interdigitated electrode (IDE) capacitor based biosensor system is preferred for development of biosensor platform. In this thesis, capacitive biosensor system with new Capacitance to Voltage Converter (CVC) designs for LoC applications is presented. Multiple IDE capacitor sensing and varactor-based compensation are new ideas that are presented in this thesis. Proposed system consists of five blocks; IDE Capacitor based tranducer, CVC, Low-Pass Filter, Linear LC-Tank Voltage Controlled Oscillator (VCO) and Class-E Power Amplifier (PA). System building blocks are designed and fabricated using IHP's 0.25 µm SiGe BiCMOS process because of its advantage at high frequency and post-process that IHP offers. Varactor tunable CVC design provides highly linear relationship between output voltage and capacitance change in sensing capacitor. Varactor is used in reference capacitor to compensate changes in sensing capacitor. Total chip area is 0.4 mm2 including pads. 10 MHz operating frequency is achieved. Total power consumption changes between 441 µW and 1,037 mW depending on the sensor capacitance

Electromechanics of an Ocean Current Turbine

The development of a numeric simulation for predicting the performance of an Ocean Current Energy Conversion System is presented in this thesis along with a control system development using a PID controller for the achievement of specified rotational velocity set-points. In the beginning, this numeric model is implemented in MATLAB/Simulink® and it is used to predict the performance of a three phase squirrel single-cage type induction motor/generator in two different cases. The first case is a small 3 meter rotor diameter, 20 kW ocean current turbine with fixed pitch blades, and the second case a 20 meter, 720 kW ocean current turbine with variable pitch blades. Furthermore, the second case is also used for the development of a Voltage Source Variable Frequency Drive for the induction motor/generator. Comparison among the Variable Frequency Drive and a simplified model is applied. Finally, the simulation is also used to estimate the average electric power generation from the 720 kW Ocean Current Energy Conversion System which consists of an induction generator and an ocean current turbine connected with a shaft which modeled as a mechanical vibration system

Electromechanics of an Ocean Current Turbine

The development of a numeric simulation for predicting the performance of an Ocean Current Energy Conversion System is presented in this thesis along with a control system development using a PID controller for the achievement of specified rotational velocity set-points. In the beginning, this numeric model is implemented in MATLAB/Simulink® and it is used to predict the performance of a three phase squirrel single-cage type induction motor/generator in two different cases. The first case is a small 3 meter rotor diameter, 20 kW ocean current turbine with fixed pitch blades, and the second case a 20 meter, 720 kW ocean current turbine with variable pitch blades. Furthermore, the second case is also used for the development of a Voltage Source Variable Frequency Drive for the induction motor/generator. Comparison among the Variable Frequency Drive and a simplified model is applied. Finally, the simulation is also used to estimate the average electric power generation from the 720 kW Ocean Current Energy Conversion System which consists of an induction generator and an ocean current turbine connected with a shaft which modeled as a mechanical vibration system