scholarly journals Analog Integrated Current Drivers for Bioimpedance Applications: A Review

Sensors ◽  
2019 ◽  
Vol 19 (4) ◽  
pp. 756 ◽  
Author(s):  
Nazanin Neshatvar ◽  
Peter Langlois ◽  
Richard Bayford ◽  
Andreas Demosthenous
Keyword(s):  
Integrated Circuit ◽  
Closed Loop ◽  
Harmonic Distortion ◽  
Open Loop ◽  
Phase Delay ◽  
Output Impedance ◽  
Wide Range ◽  
High Output Impedance ◽  
High Output

An important component in bioimpedance measurements is the current driver, which can operate over a wide range of impedance and frequency. This paper provides a review of integrated circuit analog current drivers which have been developed in the last 10 years. Important features for current drivers are high output impedance, low phase delay, and low harmonic distortion. In this paper, the analog current drivers are grouped into two categories based on open loop or closed loop designs. The characteristics of each design are identified.

scholarly journals Input switched closed-loop single phase SEPIC controlled rectifier with improved performances

2021 ◽  
Vol 11 (1) ◽  
pp. 1
Author(s):  
Md. Shamsul Arifin ◽  
Mohammad Jahangir Alam
Keyword(s):  
Power Factor ◽  
Closed Loop ◽  
Harmonic Distortion ◽  
Input Voltage ◽  
Input Power ◽  
Open Loop ◽  
Dc Power ◽  
Wide Range ◽  
Input Side ◽  
Flow Through

DC power supply has become the driving source for some essential modern applications. Thereby, DC power conditioning has become a significant issue for engineers. Typically used rectifiers associated with a bridge structure is nonlinear in nature. Thereby, the current at input side of the rectifier contains harmonics, which also flow through the power line. The presence of harmonics causes several interruptions and reduce power quality. In this regard, a new close loop SEPIC controlled rectifier is proposed in this paper. The conventional scheme is arranged with a rectifier connected to a DC-DC converter, which is an open loop system. Consequently, such system cannot regulate voltage at load varying condition. The proposed SEPIC controlled rectifier can regulate voltage under load varying condition for a wide range. Additionally, the performance in terms of total harmonic distortion (THD) of input current and power factor at AC side are also within satisfactory range for the closed loop configuration. The controlled rectifier has four operating phases associated with switching states and input voltage polarity. The close loop configuration also incorporates a current and a voltage loop at the feedback path. The comparative studies have been performed among the proposed closed loop construction, the open-loop structure as well as the conventional construction. The effectiveness of the proposed controlled rectifier is verified in terms of THD and input power factor considering the results obtained from simulation.

scholarly journals Electronically Tunable Quadrature Oscillator Using Grounded Components with Current and Voltage Outputs

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Hua-Pin Chen
Keyword(s):  
Integrated Circuit ◽  
Output Impedance ◽  
Passive Components ◽  
Quadrature Oscillator ◽  
Oscillation Condition ◽  
Transconductance Amplifier ◽  
High Output Impedance ◽  
Electronically Tunable ◽  
Current Differencing Transconductance Amplifier ◽  
High Output

The electronically tunable quadrature oscillator using a single multiple-output current controlled current differencing transconductance amplifier (MO-CCCDTA) and grounded passive components is presented. The proposed configuration uses a single MO-CCCDTA, two grounded capacitors and one grounded resistor. Two high-output impedance quadrature current signals and two quadrature voltage signals with 90° phase difference. The oscillation condition and oscillation frequency of the proposed quadrature oscillator are independently controllable. The use of only grounded passive components makes the proposed circuit ideal for integrated circuit implementation.

scholarly journals Input switched closed-loop single phase ĈUK AC to DC converter with improved power quality

2019 ◽  
Vol 10 (3) ◽  
pp. 1373
Author(s):  
Md. Shamsul Arifin ◽  
Nur Mohammad ◽  
Mohammad Ibrahim Khalil ◽  
Mohammad Jahangir Alam
Keyword(s):  
Power Factor ◽  
Single Phase ◽  
Closed Loop ◽  
Harmonic Distortion ◽  
Open Loop ◽  
Current Control ◽  
Control Loop ◽  
Cuk Converter ◽  
Wide Range ◽  
A Current

<span lang="EN-US">A new closed loop AC to DC ĈUK converter is presented in this paper. The conventional ĈUK AC to DC converter has no feedback circuit. Thereby, the output voltage of the converter changes while changing the load. The proposed closed loop converter can regulate voltage with the variation of load over a wide range. Moreover, the power factor and Total Harmonic Distortion (THD) of the supply side current found quite satisfactory from this closed loop ĈUK converter. The converter operates in four steps with a different combination of voltage polarities and switching states. The feedback path consists of a voltage control loop and a current control loop. The closed loop ĈUK converter in this study is compared with the open loop version. Additionally, the comparison is made with the conventional converter of the same topology. The effectiveness in terms of power factor and THD of the proposed converter is verified using simulation results.</span>

Comparison of Dc-Dc SEPIC, CUK and Flyback Converters Based LED Drivers

2020 ◽  
pp. 99-107
Author(s):  
Erdal Sehirli
Keyword(s):  
Integrated Circuit ◽  
Closed Loop ◽  
Input Voltage ◽  
Open Loop ◽  
Current Sensor ◽  
Switching Frequency ◽  
Led Driver ◽  
Advantages And Disadvantages ◽  
Led Drivers ◽  
Conduction Mode

This paper presents the comparison of LED driver topologies that include SEPIC, CUK and FLYBACK DC-DC converters. Both topologies are designed for 8W power and operated in discontinuous conduction mode (DCM) with 88 kHz switching frequency. Furthermore, inductors of SEPIC and CUK converters are wounded as coupled. Applications are realized by using SG3524 integrated circuit for open loop and PIC16F877 microcontroller for closed loop. Besides, ACS712 current sensor used to limit maximum LED current for closed loop applications. Finally, SEPIC, CUK and FLYBACK DC-DC LED drivers are compared with respect to LED current, LED voltage, input voltage and current. Also, advantages and disadvantages of all topologies are concluded.

scholarly journals The Design of a Charge Pump Circuit and System with Input Impedance Modulation for a Flexible-Type Thermoelectric Generator with High-Output Impedance

Electronics ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1212
Author(s):  
Kazuma Koketsu ◽  
Toru Tanzawa
Keyword(s):  
Input Impedance ◽  
Thermoelectric Generator ◽  
Charge Pump ◽  
Operating Voltage ◽  
Output Impedance ◽  
Two Phase ◽  
Pump System ◽  
High Output Impedance ◽  
A Charge ◽  
High Output

This paper describes a charge pump system for a flexible thermoelectric generator (TEG). Even though the TEG has high-output impedance, the system controls the input voltage to keep it higher than the minimum operating voltage by modulating the input impedance of the charge pump using two-phase operation with low- and high-input impedance modes. The average input impedance can be matched with the output impedance of the TEG. How the system can be designed is also described in detail. A design demonstration was performed for the TEG with 400 Ω. The fabricated system was also measured with a flexible-type TEG based on carbon nanotubes. Even with an output impedance of 1.4 kΩ, the system converted thermal energy into electric power of 30 μW at 2.5 V to the following sensor ICs.

THREE-INPUTS-ONE-OUTPUT CURRENT-MODE UNIVERSAL BIQUAD USING TWO CURRENT CONVEYORS

2013 ◽  
Vol 22 (09) ◽  
pp. 1340001 ◽  
Author(s):  
JIUN-WEI HORNG ◽  
TO-YAO CHIU ◽  
CHING-PAO HSIAO ◽  
GUANG-TING HUANG
Keyword(s):  
Integrated Circuit ◽  
Current Mode ◽  
Current Conveyors ◽  
Output Terminal ◽  
Biquadratic Filter ◽  
Component Matching ◽  
High Output Impedance ◽  
Very High ◽  
A Current ◽  
High Output

A current-mode universal biquadratic filter with three input terminals and one output terminal is presented. The architecture uses two current conveyors (CCs), two grounded capacitors and two grounded resistors; and can realize all standard second-order filter functions — highpass, bandpass, lowpass, notch and allpass. Moreover, the circuit still offers the following advantage features: very low active and passive sensitivities, using of grounded capacitors and resistors which is ideal for integrated circuit implementation, without requirements for critical component matching conditions and very high output impedance. The workability of the proposed circuit has been verified via HSPICE simulations using TSMC 0.18 μm, level 49 MOSFET technology.

Low power high output impedance high bandwidth QFGMOS current mirror

2014 ◽  
Vol 45 (8) ◽  
pp. 1132-1142 ◽  
Author(s):  
Nikhil Raj ◽  
Ashutosh Kumar Singh ◽  
Anil Kumar Gupta
Keyword(s):  
Low Power ◽  
Current Mirror ◽  
Output Impedance ◽  
High Bandwidth ◽  
High Output Impedance ◽  
High Output

scholarly journals The Modelling, Simulation and FPGA-Based Implementation for Stepper Motor Wide Range Speed Closed-Loop Drive System Design

Machines ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 56 ◽  
Author(s):  
Chiu-Keng Lai ◽  
Jhang-Shan Ciou ◽  
Chia-Che Tsai
Keyword(s):  
Embedded System ◽  
High Speed ◽  
Closed Loop ◽  
Open Loop ◽  
Drive System ◽  
Stepper Motor ◽  
Motor Drive ◽  
Digital Controllers ◽  
Loop Control ◽  
Wide Range

Owing to the benefits of programmable and parallel processing of field programmable gate arrays (FPGAs), they have been widely used for the realization of digital controllers and motor drive systems. Furthermore, they can be used to integrate several functions as an embedded system. In this paper, based on Matrix Laboratory (Matlab)/Simulink and the FPGA chip, we design and implement a stepper motor drive. Generally, motion control systems driven by a stepper motor can be in open-loop or closed-loop form, and pulse generators are used to generate a series of pulse commands, according to the desired acceleration/run/deceleration, in order to the drive system to rotate the motor. In this paper, the speed and position are designed in closed-loop control, and a vector control strategy is applied to the obtained rotor angle to regulate the phase current of the stepper motor to achieve the performance of operating it in low, medium, and high speed situations. The results of simulations and practical experiments based on the FPGA implemented control system are given to show the performances for wide range speed control.

scholarly journals Recovery of dynamics and function in spiking neural networks by closed-loop control

2015 ◽  
Author(s):  
Ioannis Vlachos ◽  
Taskin Deniz ◽  
Ad Aertsen ◽  
Arvind Kumar
Keyword(s):  
Neural Networks ◽  
Closed Loop ◽  
Brain Activity ◽  
Open Loop ◽  
Spiking Neural Networks ◽  
Delayed Feedback Control ◽  
Loop Control ◽  
Wide Range ◽  
Underlying Network ◽  
And Function

There is a growing interest in developing novel brain stimulation methods to control disease-related aberrant neural activity and to address basic neuroscience questions. Conventional methods for manipulating brain activity rely on open-loop approaches that usually lead to excessive stimulation and, crucially, do not restore the original computations performed by the network. Thus, they are often accompanied by undesired side-effects. Here, we introduce delayed feedback control (DFC), a conceptually simple but effective method, to control pathological oscillations in spiking neural networks. Using mathematical analysis and numerical simulations we show that DFC can restore a wide range of aberrant network dynamics either by suppressing or enhancing synchronous irregular activity. Importantly, DFC besides steering the system back to a healthy state, it also recovers the computations performed by the underlying network. Finally, using our theory we isolate the role of single neuron and synapse properties in determining the stability of the closed-loop system.

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