A Curvature Compensation Technique for Low-Voltage Bandgap Reference

Based on the standard 40 nm Complementary Metal Oxide Semiconductor (CMOS) process, a curvature compensation technique is proposed. Two low-voltage, low-power, high-precision bandgap voltage reference circuits are designed at a 1.2 V power supply. By adding IPTAT (positive temperature coefficient current) and ICTAT (negative temperature coefficient current) to the output resistance, the first-order compensation bandgap voltages can be obtained. Meanwhile, the third high-order compensation current is also superimposed on the same resistance. We make use of the collector current of the bipolar transistor to compensate for the nonlinear term of VBE. The simulation results show that TC (temperature coefficient) of the first circuit reference could be reduced from 29.1 × 10−6/°C to 5.71 × 10−6/°C over the temperature range of −25 to 125 °C after temperature compensation. The second one could be reduced from 17 × 10−6/°C to 5.22 × 10−6/°C.

Generation of Electricity from Waste Heat

Thermo electric generation converts heat energy into electrical energy . Power generated from TEG depends on the temperature difference between hot and cold surface . To improve the efficiency of TEG, MPPT algorithm with boost converter is used . Maximum power is obtained in the system when the output resistance of the system matches with the input resistance of TEG. By modelling the power variations generated from TEG system in series and parallel were minimized . The proposed system consists of TEG with boost converter having P& O MPPT . This paper presents simulation model of TEG module using MATLAB and is successful in generating a stable output.

Configurable Analog Block Using Current-Mode Approach

This paper introduces a new current-mode approach based configurable analog block (CAB) operating in voltage-mode with high input resistance, employing only three impedances in grounded form and providing a wide range functionality. The fourteen functions realized by the CAB include amplifiers, integrators, differentiators, and filters. The nonideal and parasitic analysis of the proposed configurable block is carried out, along with detailed simulation studies using 0.25[Formula: see text][Formula: see text]m CMOS parameters and a supply of [Formula: see text]0.75[Formula: see text]V for justifying the advance to the field. The active element used for designing the CAB exhibits 1.9 and 0.8[Formula: see text]GHz as voltage and current transfer bandwidths, respectively, while also providing low output resistance of 105[Formula: see text][Formula: see text] in voltage conveying action. Thus, the proposed CAB benefits from high frequency performance and lesser sensitivity to errors due to parasitic at that terminal. Most of the functions utilize beneficial form of grounded components. Presentation of conclusive results for integrator, all-pass filter and band-pass filter is included in form of frequency and transient responses. In-depth intermodulation distortion results for band-pass filter are further given. General conclusive annotations on analog circuit design are made at the end of this study.

Combination of HP and LP filters for narrow band antialiasing filter

The discrete time signal processing requires an anti-aliasing filter at the input and a reconstruction filter at output. Some filters of biquads structure are characterized by a decreasing of the attenuation at high frequencies, caused by the final value of the output resistance of the operational amplifier. In this paper we discuss a design of combined BP filter without mentioned decrease. The proposed filter structure was verified by SPICE simulation.

Sensing and Delineating Mixed-VOC Composition in the Air Using a Single Metal Oxide Sensor

Monitoring volatile organic compounds (VOCs) places a crucial role in environmental pollutants control and indoor air quality. In this study, a metal-oxide (MOx) sensor detector (used in a commercially available monitor) was employed to delineate the composition of air containing three common VOCs (ethanol, acetone, and hexane) under various concentrations. Experiments with a single component and double components were conducted to investigate how the solvents interact with the metal oxide sensor. The experimental results revealed that the affinity between VOC and sensor was in the following order: acetone > ethanol > n-hexane. A mathematical model was developed, based on the experimental findings and data analysis, to convert the output resistance value of the sensor into concentration values, which, in turn, can be used to calculate a VOC-based air quality index. Empirical equations were established based on inferences of vapour composition versus resistance trends, and on an approach of using original and diluted air samples to generate two sets of resistance data per sample. The calibration of numerous model parameters allowed matching simulated curves to measured data. Therefore, the predictive mathematical model enabled quantifying the total concentration of sensed VOCs, in addition to estimating the VOC composition. This first attempt to obtain semiquantitative data from a single MOx sensor, despite the remaining selectivity challenges, is aimed at expanding the capability of mobile air pollutants monitoring devices.