Equivalent series resistance

About: Equivalent series resistance is a research topic. Over the lifetime, 5335 publications have been published within this topic receiving 83362 citations. The topic is also known as: ESR.

Modeling and simulation of single nanobelt SnO2 gas sensors with FET structure

Abstract: Individual tin dioxide nanobelts were used to fabricate field-effect transistor (FET) devices. The output characteristics of these devices have been measured under various ambient conditions, and modeled with a modified drift-diffusion model in which quantum mechanical effects are taken into consideration using the density-gradient model. It is shown that the saturation of the output curves (drain current versus drain-to-source voltage) in air is not due to channel pinch-off, but rather to the saturation of the reversed-biased current of the Schottky-like contact. In this case the source and drain contacts behave like rectifying diodes and can be modeled as two Schottky diodes connected back-to-back with a series resistance from the nanobelt separating the diodes. In the presence of hydrogen the rectifying behavior of the two contacts disappears and the current through the device is limited by the resistance of the nanobelt that can be modulated efficiently by using a gate electrode.

Drive level dependence of the resonant frequency in BAW quartz resonators and his modeling

Abstract: The influence of the excitation current on the resonant frequency and its mathematical description makes necessary the introduction of a nonlinear impedance characteristic of the piezoelectric resonator. This influence was modeled by the nonlinear electrical equivalent circuit; the equivalent series resistance and equivalent motional capacitance are taken to be functions of the amplitude of the excitation current by means of the relations derived in the work. The equivalent circuit was analyzed by the method of equivalent linearization. The relationships between the amplitudes of voltage applied on the AT-cut resonator and the first current harmonics or phase-frequency dependence of the excited resonator, respectively, are derived. Amplitude jumps and dynamic temperature change phenomena are discussed.

Digital Enhanced V 2 -Type Constant On-Time Control Using Inductor Current Ramp Estimation for a Buck Converter With Low-ESR Capacitors

Abstract: This paper proposes a new digital enhanced V2-type constant on-time control architecture for solving the ripple oscillation issues when using low-equivalent series resistance (ESR) capacitors in a buck converter. Instead of directly sensing the inductor current, an inductor current ramp estimator with the drift compensation is presented as adding a virtual ESR ripple to the output voltage. Only the input and output voltages are required to be sampled with analog-to-digital converters (ADCs) for estimating the inductor current ramp. Since the sampling rate and resolution requirements of ADCs for voltage sensing are usually less critical with compared to direct current sensing, the proposed digital control architecture is practical for low-cost applications. Besides, the limit-cycle oscillations due to the sampling effects can also be improved by using the estimated current ramp. Furthermore, the small-signal model of the proposed digital enhanced V2 control architecture is provided to design the estimated current ramp amplitude to stabilize the system and to optimize the system performance. The drift compensation effect is also analyzed in this paper. The effectiveness of the proposed control architecture with the current ramp estimator has been verified with simulation and experimental results by using an FPGA-based hardware platform.

Degradation of silicon bipolar junction transistors at high forward current densities

Abstract: The physical degradation mechanisms of silicon bipolar function transistors at high forward current densities were delineated quantitatively using three n/p/p and one p/n/p state-of-the-art submicron polysilicon-emitter transistor technologies. The increase of the operating current gain and decrease of emitter series resistance from million-ampere per square centimeter stress current are related to hydrogenation of the electronic traps at the metal-silicide/polycrystalline-Si and polycrystalline-Si/crystalline-Si emitter contact interfaces. A demonstration of the 10-year operation Time-to-Failure extrapolation methodology is also presented.

Single heterojunction Pb1−x Snx Te diode lasers

Abstract: Single heterojunction diode lasers in the Pb1−xSnx Te alloy system have been fabricated by low‐temperature vacuum deposition of n‐PbTe on a p‐Pb0.88Sn0.12 Te substrate. The lasers have lower threshold current densities and operate cw at higher temperatures than homojunction devices in this material. At laser threshold the incremental diode resistance drops abruptly from 0.5 Ω to a series resistance limited value of 0.08 Ω, a previously unobserved effect in diode lasers which indicates very high internal quantum efficiency.