Design and Noise Analysis of a Novel Auto-Zeroing Structure for Continuous-Time Instrumentation Amplifiers

This paper introduces a low-noise, low-power amplifier for high-impedance sensors. An innovative circuit using an auto-zeroed architecture combined with frequency modulation to reject offset and low-frequency noise is proposed and analysed. Special care was given to avoid broadband noise aliasing and chopping in the signal path, and to minimize both the resulting equivalent input offset voltage and equivalent input biasing current. The theoretical noise analysis of the proposed topology covers most of the noise sources of the circuit. Simulations show that the input-referred noise level of the circuit is 13.4nV/pHz for a power consumption of 85μA with a power supply from 1.8V to 3.6V

PAD: A New Interactive Knowledge-Based Analog Design Approach

This paper presents a new Procedural Analog Design tool called PAD. It is a chart-based design environment dedicated to the design of analog circuits aiming to optimize design and quality by finding good tradeoffs. This interactive tool allows step-by-step design of analog cells by using guidelines for each analog topology. Its interactive interface enables instantaneous visualization of design tradeoffs. At each step, the user modifies interactively one subset of design parameters and observes the effect on other circuit parameters. At the end, an optimized design is ready for simulation (verification and fine-tuning). The present version of PAD covers the design of basic analog structures (one transistor or groups of transistors) and the procedural design of transconductance amplifiers (OTAs) and different operational amplifier topologies. The basic analog structures' calculator embedded in PAD uses the complete set of equations of the EKV MOS model, which links the equations for weak and strong inversion in a continuous way [1, 2]. Furthermore, PAD provides a layout generator for matched substructures such as current mirrors, cascode stages and differential pair

Offset Drift Dependence of Hall Cells with their Designed Geometry

In this paper, the performance of CMOS Hall Effect Sensors with four different geometries has been experimentally studied. Using a characteristic measurement system, the cells residual offset and its temperature behavior were determined. The offset, offset drift and sensitivity are quantities that were computed to determine the sensors performance. The temperature coefficient of specific parameters such as individual, residual offset and resistance has been also investigated. Therefore the optimum cell to fit the best in the performance specifications was identified. The variety of tested shapes ensures a good analysis on how the sensors performance changes with geometry

A DC power flow extension

In this work an extension of the well-known DC power flow method is presented. A normal DC power flow of the system is executed to determine voltage angles and a novel derivation of voltage amplitudes is devised. The latter is rigorously formulated and eight alternative ways to tackle it are proposed. Comparative studies between the proposed versions of the algorithm verify its effectiveness in producing an accurate estimate of the voltage profile, on average in the order of 10-3 pu close to the exact solution. The proposed algorithm features very favorable computational requirements of approximately a fifth of the time required for an exact solution. Its computational efficiency renders it a solid candidate for hard real-time applications required in the emerging smart grid

Generator coherency identification algorithm using modal and time-domain information

Coherency group identification is an integral constituent part of the wider field of reduction techniques in power systems. It consists of separating the machines in the system into groups that feature similar behavior. This paper presents a coherency identification algorithm for dynamic studies. The algorithm combines both modal and time domain techniques in an effort to combine the merits of both approaches. Its outcome is a suggested optimal number of clusters alongside the clustering itself. Tests have been conducted on a sample power system of 39 buses and its validity has been demonstrated

An ultra-low power energy-efficient microsystem for hydrogen gas sensing applications

This paper presents a fully integrated power management and sensing microsystem that harvests solar energy from a micro-power photovoltaic module for autonomous operation of a miniaturized hydrogen sensor. In order to measure H2 concentration, conductance change of a miniaturized palladium nanowire sensor is measured and converted to a 13-bit digital value using a fully integrated sensor interface circuit. As these nanowires have temperature cross-sensitivity, temperature is also measured using an integrated temperature sensor for further calibration of the gas sensor. Measurement results are transmitted to the base station, using an external wireless data transceiver. A fully integrated solar energy harvester stores the harvested energy in a rechargeable NiMH microbattery. As the harvested solar energy varies considerably in different lighting conditions, the power consumption and performance of the sensor is reconfigured according to the harvested solar energy, to guarantee autonomous operation of the sensor. For this purpose, the proposed energy-efficient power management circuit dynamically reconfigures the operating frequency of digital circuits and the bias currents of analog circuits. The fully integrated power management and sensor interface circuits have been implemented in a 0.18μm CMOS process with a core area of 0.25mm2. This circuit operates with a low supply voltage in the 0.9-1.5V range. When operating at its highest performance, the power management circuit features a low power consumption of less than 300nW and the whole sensor consumes 14.1μ

Measurement and Performance Evaluation of a Silicon On Insulator Pixel Matrix

A new technique for driving silicon-on-insulator pixel matrixes has been proposed in [1], which was based on transient charge pumping for evacuating the extra photogenerated charges from the body of the transistor. An 8x8 pixel matrix was designed and fabricated using the above technique. In this paper, the measurement set-up is described and the performance evaluation procedure is given, together with results of its implementation on the fabricated pixel matrix. The results show the applicability of the charge pumping technique and the effective operation of the image sensor

An ultra-low power energy-efficient microsystem for hydrogen gas sensing applications

This paper presents a fully integrated power management and sensing microsystem that harvests solar energy from a micro-power photovoltaic module for autonomous operation of a miniaturized hydrogen sensor. In order to measure H-2 concentration, conductance change of a miniaturized palladium nanowire sensor is measured and converted to a 13-bit digital value using a fully integrated sensor interface circuit. As these nanowires have temperature cross-sensitivity, temperature is also measured using an integrated temperature sensor for further calibration of the gas sensor. Measurement results are transmitted to the base station, using an external wireless data transceiver. A fully integrated solar energy harvester stores the harvested energy in a rechargeable NiMH microbattery. As the harvested solar energy varies considerably in different lighting conditions, the power consumption and performance of the sensor is reconfigured according to the harvested solar energy, to guarantee autonomous operation of the sensor. For this purpose, the proposed energy-efficient power management circuit dynamically reconfigures the operating frequency of digital circuits and the bias currents of analog circuits. The fully integrated power management and sensor interface circuits have been implemented in a 0.18 mu m CMOS process with a core area of 0.25 mm(2). This circuit operates with a low supply voltage in the 0.9-1.5 V range. When operating at its highest performance, the power management circuit features a low power consumption of less than 300 nW and the whole sensor consumes 14.1 mu A