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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.


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Patent
31 May 2000
TL;DR: In this paper, the effects of a headroom resistor and an offset resistor in one resistor string are negated by configuring an output amplifier with appropriate gain resistors, and a highly accurate D/A conversion can be achieved by utilizing all resistors of the main and sub-resistor strings with the same value.
Abstract: A digital-to-analog converter having series-connected transistors forming high impedance current sources for respective segmented resistor strings. A series transistor forming a current sink for one resistor string presents a high output impedance by utilizing a negative feedback amplifier. The effects of a headroom resistor and an offset resistor in one resistor string are negated by configuring an output amplifier with appropriate gain resistors. A highly accurate D/A conversion can be achieved by utilizing all resistors of the main and sub-resistor strings with the same value.

50 citations

Patent
04 Jun 1984
TL;DR: An ion generator for the formation of electrostatic images, including two electrodes (32, 34) at opposite faces of a solid dielectric member, using a threshold multiplexing principle for the drive circuit, is described in this paper.
Abstract: An ion generator for the formation of electrostatic images, including two electrodes (32, 34) at opposite faces of a solid dielectric member (31), using a threshold multiplexing principle for the drive circuit. This apparatus provides a drive signal to each electrode to generate ions in an air region adjacent one of the electrodes, which ions are extracted for electrostatic imaging. Two drive signals each consisting of a sinusoidal alternating potential, out of phase by 180o, intermittently induce the production and extraction of ions. Other time-varying potentials of like electrical characteristics may be used, providing a number of operating advantages. The ion generator produces ions only during print periods, and requires reduced power to achieve given ion outputs. The control electrode (33) may be partially encapsulated to limit the discharge region. Drive circuitry such as low source impedance gated oscillators, or other low impedance drivers, reduce capacitive "cross-talk" in a multielectrode device.

50 citations

Patent
25 Nov 1987
TL;DR: A tristate output circuit includes a pair of transistors having sources connected to a switchable current source and drains separately coupled to a voltage source through separate resistors and switching transistors as mentioned in this paper.
Abstract: A tristate output circuit includes a pair of transistors having sources connected to a switchable current source and drains separately coupled to a voltage source through separate resistors and switching transistors. When the current source and switching transistors are on, the circuit operates in a back termination mode wherein it amplifies a differential input signal applied across the gates of the transistor pair to produce a differential output signal across their drains for transmission on a transmission line. The load resistors are sized to match the characteristic impedance of a transmission line so as to properly terminate the transmission line. In an open drain mode, the switching transistors are off, uncoupling the drains of the transistor pair from the voltage source so as to increase output impedance. In a tristate mode, the current source and switching transistors are turned off, thereby turning off the transistor pair and rendering the output impedance of the circuit substantially infinite.

50 citations

Journal ArticleDOI
TL;DR: In this article, a new technique for enhancing the transconductance and low frequency output impedance of recycling folded cascode amplifiers is presented by using a positive feedback and upgrading the recycling structure.
Abstract: In this paper, a new technique for enhancing the transconductance and low frequency output impedance of recycling folded cascode amplifiers is presented. These improvements were achieved by using a positive feedback and upgrading the recycling structure. The new structure benifits from better transconductance, slew rate, and DC gain in comparison to conventional folded cascode (FC) amplifier. Moreover, the input referred noise and input offset are reduced and the phase-margin is improved. The improved amplifier is simulated in 0.18 µm CMOS technology, demonstrates a DC gain enhancement of 16.4 dB as well as 117.5 MHz increase in gain bandwidth compared with conventional FC configuration. The amplifier consumes 360 µW @ 1.2 V which makes it appropriate for low-voltage applications.

50 citations

Journal ArticleDOI
TL;DR: The proposed UDE-based robust power flow control is developed for grid-connected inverters to achieve accurate power delivery to the grid and is easy for the implementation and parameter tuning through the design of the desired tracking error dynamics and the UDE filters.
Abstract: In this paper, an uncertainty and disturbance estimator (UDE)-based robust power flow control is developed for grid-connected inverters to achieve accurate power delivery to the grid. The model of power delivering with both frequency dynamics and voltage dynamics is derived at first. The UDE method is introduced into the controller design to deal with model uncertainties (e.g., output impedance and power angle), coupling effects, and external disturbances (e.g., the fluctuation of the dc-link voltage, the variation of output impedance/line impedance, and the variations of both frequency and amplitude in the grid voltage). Also, this controller does not need a voltage regulator or a current regulator and is easy for the implementation and parameter tuning through the design of the desired tracking error dynamics and the UDE filters. Experimental results are provided to show the effectiveness of the proposed method for different disturbance rejection scenarios, the low-voltage fault-ride through capability, and the weak grid operation capability. The good robustness of the UDE-based control is also demonstrated through the comparison with two other controllers: the proportional–integral controller and the active disturbance rejection controller.

50 citations


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