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Output impedance

About: Output impedance is a research topic. Over the lifetime, 11185 publications have been published within this topic receiving 134949 citations.


Papers
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Patent
27 Jul 2005
TL;DR: In this article, a method and an apparatus for determining an impedance experienced by a lead associated with the implantable device is presented, where a substantially constant current signal is provided through a first terminal and a second terminal of the lead and a voltage across the first and second terminals is measured.
Abstract: A method and an apparatus for determining an impedance experienced by a lead associated with the implantable device. A substantially constant current signal is provided through a first terminal and a second terminal of the lead. A voltage across the first and second terminals is measured. An impedance across the first and second terminals is determined based upon the constant current signal and the measured voltage.

76 citations

Journal ArticleDOI
TL;DR: In this article, a differential rectifier with high radio frequency (RF)-dc conversion efficiency over an extended input power range by using resistance compression network (RCN) was presented.
Abstract: This paper presents a differential rectifier with high radio frequency (RF)-dc conversion efficiency over an extended input power range by using resistance compression network (RCN). The RCN is cascaded with a typical differential rectifier. It can reduce the variation range of rectifier input impedance, which changes with input power levels, and better impedance matching can be realized. Thus, the loss due to impedance mismatch is reduced, and high efficiency can be obtained in a wider input power range. First, the theoretical analysis of the RCN is carried out. Then, the detailed analysis of the rectifier input impedance and efficiency is derived in closed form. Based on the analytical results, a 915-MHz rectifier incorporating RCN is implemented. The measured results show that the RF-dc conversion efficiency keeps above 50% and 70% in the input power range 5.5–33.1 and 13.5–31.3 dBm, respectively. The maximum efficiency is 84.8%. Compared with the counterpart without RCN, the efficiency at lower input power levels is improved without degrading the peak efficiency.

75 citations

Proceedings ArticleDOI
01 Jul 2017
TL;DR: In this article, the authors investigated the origins of the voltage imbalance in practical implementations of flying capacitor multilevel (FCML) converters and presented corresponding solutions to solve the problem.
Abstract: Flying capacitor multilevel (FCML) converters are known to naturally balance the capacitor voltages through the use of phase-shifted pulse-width modulation. However, in practice, the capacitor voltages can still deviate and active balancing is often required. This work investigates the origins of the voltage imbalance in practical implementations of such converters and presents corresponding solutions. It is shown that the source impedance and the input capacitor can have a drastic impact on the flying capacitor voltages. Moreover, we also demonstrate that an FCML converter with an even number of levels has significantly better immunity to the presence of source impedance than one with an odd number of levels. It is also found that gate signal propagation delay mismatch from half-bridge gate drivers will lead to capacitor imbalance. An alternative gate drive power supply circuit is designed to address this problem. Lastly, variations of switches' on-resistance are found to have a small impact on the capacitor voltage balance.

75 citations

Patent
10 Feb 1997
TL;DR: The field effect phototransistor (FEP) as mentioned in this paper is a three-terminal photo-transistor based on integrated metal oxide semiconductor (MOS) technology, which is more compatible with MOS VLSI technology by inherently being a unipolar type device.
Abstract: A field-effect photo-transistor, being a three-terminal photosensing electrical device, based on integrated metal oxide semiconductor (MOS) technology. The device features a high output impedance which makes it particularly suitable as a photosensor for active pixel imaging arrays. Unlike the bipolar photo-transistor, which is a device well known in the art, the field-effect phototransistor is more compatible with MOS VLSI (Very Large Scale Integration) technology by inherently being a unipolar type device. Active pixel imaging arrays based on the disclosed invention can be integrated on the same semiconductor substrate with conventional digital or mixed signal processing functions to produce single-chip image processors for video or still picture cameras.

75 citations

Journal ArticleDOI
TL;DR: In this paper, a dual-loop feedback and a unique structure with symmetric signal paths for voltage and current signals were proposed for variable-frequency control of high-current low-voltage dc-dc converters.
Abstract: For controlling high-current low-voltage dc–dc converters, the control methods with variable switching frequency have the potential to achieve fast transient response and high efficiency. However, some issues in practical design limit the usefulness of the conventional variable-frequency control methods, such as the voltage-mode hysteretic control. This letter presents a novel implementation of current-mode variable-frequency control. The system architecture features a dual-loop feedback and a unique structure with symmetric signal paths for voltage and current signals. The symmetric structure provides practical advantages for integrated controller design to achieve accurate control on the droop resistance (or the load-line resistance). The system dynamics are analyzed with the small-signal model. Design guidelines are derived for simple compensation circuits to achieve constant output impedance. With variable switching frequency, the system achieves good dynamic response without requiring high switching frequency at steady-state. The system performance was verified by a two-channel interleaved controller chip implemented with CMOS technology.

75 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202347
2022140
2021182
2020285
2019366
2018377