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Negative impedance converter

About: Negative impedance converter is a research topic. Over the lifetime, 5801 publications have been published within this topic receiving 87636 citations.


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Journal ArticleDOI
TL;DR: In this article, the authors proposed to add feed-forward of output current and input voltage to a current-mode controller, which is applicable to both forward and flyback types of converters and to all types of currentmode control.
Abstract: Near-optimum dynamic regulation of a dc-dc converter is obtained by adding feed-forward of output current and input voltage to a current-mode controller. The results are a) near zero output impedance and audio susceptibility, from dc to nearly the switching frequency, b) much reduced magnitude, duration, and energy content of the output-voltage transient after a transient change of output current or input voltage, and c) smaller size and lower cost for the output filter capacitor. Feed-forward is applicable to both forward and flyback types of converters and to all types of current-mode control. The cost of feed-forward for a forward-type converter is a low-power resistor and a current sensor; a flyback-type converter needs also an analog multiplier-divider integrated circuit (IC). A description is given of the control loop, conditions to achieve extremely good transient response, calculation of the peak deviation of the output voltage for a step load change, practical methods for current feed-forward, and experimental results. The theoretical predictions are in excellent agreement with the experimental results. In the experiments, adding output-current feed-forward reduced the transient deviations of output voltage by factors of 6.7 in magnitude, 50 in duration, and 335 in energy content. The added components were a 1/4-W resistor and a 12-mm ferrite toroid with a 10-turn winding.

208 citations

Journal ArticleDOI
TL;DR: In this article, a broadband active shunt technique for controlling vibration in piezoelectric laminated structures is proposed, which is similar in nature to passive shunt damping techniques.
Abstract: In this paper a broadband active shunt technique for controlling vibration in piezoelectric laminated structures is proposed. The effect of the negative capacitance controller is studied theoretically and then validated experimentally on a piezoelectric laminated simply supported plate. The 'negative capacitance controller' is similar in nature to passive shunt damping techniques, as a single piezoelectric transducer is used to dampen multiple modes. While achieving comparable performance to that of the passive shunt schemes, the negative capacitance controller has a number of advantages. It is simpler to implement, less sensitive to environmental variations and can be considered as a broadband vibration absorber.

208 citations

Journal ArticleDOI
TL;DR: In this paper, the authors report subthreshold swings as low as 8.5 mV/decade over as high as eight orders of magnitude of drain current in short-channel negative capacitance FinFETs with gate length $L_{g}=100$ nm.
Abstract: We report subthreshold swings as low as 8.5 mV/decade over as high as eight orders of magnitude of drain current in short-channel negative capacitance FinFETs (NC-FinFETs) with gate length $L_{g}=100$ nm. NC-FinFETs are constructed by connecting a high-quality epitaxial bismuth ferrite (BiFeO3) ferroelectric capacitor to the gate terminal of both n-type and p-type FinFETs. We show that a self-consistent simulation scheme based on Berkeley SPICE Insulated-Gate-FET Model:Common Multi Gate model and Landau–Devonshire formalism could quantitatively match the experimental NC-FinFET transfer characteristics. This also allows a general procedure to extract the effective $S$ -shaped ferroelectric charge–voltage characteristics that provides important insights into the device operation.

206 citations

Journal ArticleDOI
TL;DR: In this article, a novel interleaved high step-up converter with WCCIs and voltage multiplier cells is proposed, which minimizes the peak current ripple of the power devices and makes low-voltage MOSFETs with high performance available in high output voltage applications.
Abstract: The concept of winding-cross-coupled inductors (WCCIs) and voltage multiplier cells is integrated to derive a novel interleaved high step-up converter in this paper. The voltage gain is extended and the switch voltage stress is reduced by the WCCIs and the voltage multiplier cells in the presented circuit, which minimizes the peak current ripple of the power devices and makes low-voltage MOSFETs with high performance available in high step-up and high output voltage applications. Moreover, the output diode reverse-recovery problem is alleviated by the leakage inductance of the WCCIs, which reduces the reverse-recovery losses. Zero current switching (ZCS) turn-on is realized for the power switches to reduce the switching losses. Furthermore, the voltage spikes on the MOSFETs are clamped and the leakage energy is recycled by the voltage multiplier cells, when the switch turns off. A 1 kW prototype with 35-45 V input and 380 V output operating at 50 kHz switching frequency is built and tested to verify the significant improvements of the proposed converter.

203 citations

Patent
20 Dec 2006
TL;DR: In this article, a voltage conversion means based on an input control signal converts the magnitude of the voltage from the power supply to another magnitude that is desired at the high side of the load.
Abstract: The present invention provides a drive and control apparatus provides a desired switched current to a load including a string of one or more electronic devices. A voltage conversion means, based on an input control signal converts the magnitude of the voltage from the power supply to another magnitude that is desired at the high side of the load. A dimming control means provides control for activation and deactivation of the load and may further provide a means for current limiting. A feedback means is coupled to the voltage conversion means and a current sensing means and provides a control signal to the voltage conversion means that is indicative of voltage drop across the current sensing means which represents the current flowing through the load. Based on the control signal received, the voltage conversion means can subsequently adjust its output voltage such that a constant switched current is provided to the load.

203 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202330
2022104
2021120
2020131
2019134
2018155