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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
Ho-young Song1
13 Jan 2003
TL;DR: In this article, a detection circuit detects whether the external reference resistor is electrically connected to the semiconductor integrated circuit, and disables the impedance control circuit based on a detection result.
Abstract: A semiconductor integrated circuit device which includes a termination circuit for terminating a bus line. An impedance control circuit controls impedance of the termination circuit in accordance with impedance of an external reference resistor, so as to have the same or substantially the same impedance as that of the external reference resistor. A detection circuit detects whether the external reference resistor is electrically connected to the semiconductor integrated circuit, and disables the impedance control circuit based on a detection result.

35 citations

Proceedings ArticleDOI
17 Sep 2003
TL;DR: In this paper, a new CMOS current source has been described for biomedical implantable microstimulators by utilizing MOS transistors in deep triode region as linearized voltage controlled resistors in order to achieve a large voltage compliance of up to 97% of the supply levels while maintaining high output impedance in the tens of mega-ohm range.
Abstract: A new CMOS current source has been described for biomedical implantable microstimulators by utilizing MOS transistors in deep triode region as linearized voltage controlled resistors in order to achieve a large voltage compliance of up to 97% of the supply levels while maintaining high output impedance in the tens of mega-ohm range to keep the desired stimulation current levels constant within 1% of their nominal values irrespective of the site and tissue impedances. The new approach can improve stimulation efficiency, elongate power supply longevity, and save chip area especially when the stimulation current level is high. The current source has been used in a prototype 4-channel wireless stimulator chip fabricated in AMI 1.5-/spl mu/m 2M/2P standard CMOS process. With 5 V supply, each site driver channel provides at least 4.25 V compliance and 10 M/spl Omega/ output resistance while sinking up to 210 /spl mu/A and occupies 0.05 mm/sup 2/ of chip area.

35 citations

Journal ArticleDOI
TL;DR: In this paper, the performance of a current source-based bio-impedance spectroscopy (BIS) measurement system was compared with a voltage source based BIS, which use common components.
Abstract: Current sources are widely used in bio-impedance spectroscopy (BIS) measurement systems to maximize current injection for increased signal to noise while keeping within medical safety specifications. High-performance current sources based on the Howland current pump with optimized impedance converters are able to minimize stray capacitance of the cables and setup. This approach is limited at high frequencies primarily due to the deteriorated output impedance of the constant current source when situated in a real measurement system. For this reason, voltage sources have been suggested, but they require a current sensing resistor, and the SNR reduces at low impedance loads due to the lower current required to maintain constant voltage. In this paper, we compare the performance of a current source-based BIS and a voltage source-based BIS, which use common components. The current source BIS is based on a Howland current pump and generalized impedance converters to maintain a high output

34 citations

Journal ArticleDOI
TL;DR: A method for measuring the complex impedance of bolometers and calorimeters that allows experimenters to easily isolate the device impedance from the effects of parasitic impedances and frequency dependent gains in amplifiers.
Abstract: Impedance measurements provide a useful probe of the physics of bolometers and calorimeters. We describe a method for measuring the complex impedance of these devices. In previous work, stray impedances and readout electronics of the measurement apparatus have resulted in artifacts in the impedance data. The technique allows experimenters to find an independent Thevenin or Norton equivalent circuit for each frequency. This method allows experimenters to easily isolate the device impedance from the effects of parasitic impedances and frequency dependent gains in amplifiers.

34 citations

Journal ArticleDOI
TL;DR: The adaptive biasing technique increases both loop bandwidth and slew-rate of the LDO by 100% at full load condition without changing no-load quiescent current, and direct feedback to gate-to-source voltage of the NMOS regulation FET provides fast load transient response.
Abstract: This paper presents an output external capacitor-less, fully integrated, fast settling NMOS low-dropout (LDO) regulator with adaptively biased error amplifier (EA) for system-on-chip core applications. The adaptive biasing technique increases both loop bandwidth and slew-rate of the LDO by 100% at full load condition without changing no-load quiescent current. Direct feedback to gate-to-source voltage of the NMOS regulation FET provides fast load transient response. The proposed LDO employs a cross-coupled common-gate input based EA, with transconductance boosting, achieving twice unity-gain bandwidth in comparison to a typical folded-cascode common-source input stage. Low output impedance of NMOS regulation stage and low input impedance of the EA reduce load dependent stability issue. The proposed regulator is designed and fabricated in a 0.18- $\mu \text{m}$ CMOS technology with die-area of 0.21 mm2. The LDO generates a regulated output voltage of 1.4–1.6 V from an input voltage of 1.6–1.8 V, consumes 133 $\mu \text{A}$ quiescent current, and supports 0 pF to 50 pF load capacitance. Measured results show 166 mV undershoot with 19 ns settling time for a load step from 9 mA to 40 mA in 350 ps edge-time for zero-load capacitance. After using adaptive biasing, the settling time is reduced by 37% and 36% for 0 pF and 50 pF load, respectively.

34 citations


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