Search results for "Operational amplifier"
showing 6 items of 6 documents
Photovoltaic plant array reconfiguration: Design of a new device
2014
An efficient strategy to improve unequally irradiated PV plants performances is based on the reconfiguration of the connections between the modules. In this paper, an algorithm, for this purpose conceived, is presented. Moreover, the design, realization and finally also the set up of a new reconfiguration system device is fully shown and discussed. The algorithm conceived simulates several possible series-parallel connections under varying irradiation conditions, and determines the optimal modules connection in order to get the maximum output power. In this way, the reconfiguration system may set up the reconfiguration strategy. The reconfiguration system prototype set up, basically consist…
Transconductance Converters Based on Current Mirrors Applied to pH Measurement Using ISFET Sensors
2009
New transconductance circuits (V/I converters) are designed based on current mirrors and operational amplifiers. Their input/output characteristics and the influence of DC parameters are obtained. Experimental results were performed, comparing them with the simulated results. An electronic instrumentation circuit is designed based on one of the transconductance converters analyzed. The purpose of this circuit was to condition the response of an ion-sensitive field-effect transistor (ISFET) to measure pH. In the proposed application, the V/I converter presented provides the stability and accuracy of the ISFET operating point, making an easy characterization procedure and the design of multic…
Sub-kelvin current amplifier using DC-SQUID
2000
Abstract We have set up a system where a low-noise DC-SQUID is used as a current amplifier. The SQUID output is read using a wide band electronics unit based on the noise cancellation scheme. The SQUID has been installed in a compact Nanoway PDR50 dilution refrigerator, and superconducting transitions of Ti/Au thermometer strips for X-ray calorimeter applications have been measured. We can operate at 100 mK using a SQUID with Pd shunt resistors. Noise and bandwidth results of the setup are presented.
Programmable VLSI cubic-like function implementation
2006
An analogue VLSI implementation of a cubic-like function is presented, whose design is focused to reduce the circuit complexity. Simulations show that the V–I characteristic of the circuit resembles a cubic function, which can be easily adjusted by changing the bias parameters.
CMOS Capacitance-to-Time Converter-Based Interface for Differential Capacitive Sensors
2020
This paper presents pre-layout simulation results on a CMOS implementation of a capacitance-to-time converter-based electronic interface for differential capacitive sensors. Its simple architecture, comprising only three operational amplifiers (OA) and a digital mixer (inverted XOR gate) allows, by properly setting the values of seven biasing resistors, to fit the working range anywhere from few fF to hundreds of pF, giving the output quasi-digital signals (T and PW) in the useful μs-ms range (appropriate for direct interfacing with general purposes microcontrollers). A couple of illustrative examples are provided.
Novel constant current driver for ISFET/MEMFETs characterization
2001
Abstract In the present work a new constant current driver for ISFETs and MEMFETs sensors has been developed. The proposed circuit maintains the ISFET/MEMFET operation point at constant drain–source current and voltage. The combination of some programmable current sources and an appropriate selection of a simple precision resistor allow a good ISFET/MEMFET polarization. The use of operational amplifiers with low offset and drift are required to provide the buffering function needed by the sensor.