Showing papers on "RC circuit published in 2016"

Unified Equivalent Circuit Model and Optimal Design of $V^{2}$ Controlled Buck Converters

Abstract: $V^{2}$ control has advantages of simple implementation and fast transient response and is widely used in industry for point-of-load applications. This control scheme is elegant when output capacitors with large RC time constant are employed, such as OSCON capacitors. However, in most cases using capacitors with small RC time constant, such as ceramic capacitors, instability problem will occur. Previous modeling methods including sampled-data modeling, discrete-time analysis, time-domain analysis, and describing function are all very mathematical and difficult to apply for practical engineers as little physical insight can be extracted. Up to now, no equivalent circuit model is proposed which is able to predict the instability issue and serve as a useful design tool for $V^{2}$ control. This paper proposes a unified equivalent circuit model which is applicable to all types of capacitors by considering the effect of capacitor voltage ripple. The equivalent circuit provides the physical insight of $V^{2}$ control as a nonideal voltage source, a dual concept of previous nonideal current source for current-mode control. The equivalent circuit model is a simple yet accurate complete model and is very helpful for design purpose. Optimal design guidelines for point-of-load applications are provided. The proposed equivalent circuit model is applicable to both variable frequency modulation and constant frequency modulation. The equivalent circuit model and design guidelines are verified with Simplis simulation and experimental results.

First-order low-pass negative group delay passive topology

Abstract: An innovative theory on the passive circuits capable to generate low-pass negative group delay (NGD) behaviour is introduced. An identification method enabling to identify the first-order NGD simple cells built with resistor-inductor (RL)- and resistor-capacitor (RC)-networks is elaborated. The fundamental characteristics as the NGD level and cut-off frequency are formulated from the low-pass NGD circuit canonical transfer function. The NGD existence conditions are derived in function of the established topology parameters. Despite the attenuation systematically related to the passive cell nature, low-pass NGD behaviours with tens ns NGD level and tens MHz bandwidth were obtained with an example of lumped RL-network-based L-topology circuit. Transient analysis was performed to illustrate that the NGD phenomenon enables to exhibit baseband signal advance effect. The proposed NGD topology simplicity promises their potential applications especially in term of signal correction and the modern electronic system improvement.

Equivalent circuit model parameters estimation of Li-ion battery: C-rate, SOC and temperature effects

Abstract: The paper describes the estimation of parameters of battery model at various temperatures for the Li-ion battery. The estimation of parameters employs experimental methods that are time-consuming, expensive and require high computational power. Hence, second-order RC network equivalent circuit model parameters estimation is done using GA, PSO, and DE optimization techniques. For proper evaluation, the mathematical model was build to incorporate the effect of the state of charge, c-rate and temperature variations in the battery. Estimation has been done in terms of the predicted voltage curve's closeness to the known true voltage curve. Feasibility of various optimization techniques is examined by the accuracy of predicted model and the rate of convergence in the estimation of the model parameters. Investigation showed that the DE algorithm has the best accuracy among the meta-heuristic optimizers for battery parameter estimation at various temperatures of both charging and discharging scenario. Further analysis showed DE algorithm was reliable as well as computationally less expensive compared to other optimization techniques.

GaN-HEMT dynamic ON-state resistance characterisation and modelling

Abstract: GaN-HEMTs suffer from trapping effects which might increase device ON-state resistance (R DS(on) ) values. Thus, dynamic R DS(on) of a commercial GaN-HEMT is characterized at different bias voltages in the paper by a proposed measurement circuit. Based on the measurement reaults, a behavioural model is proposed to represent device dynamic R DS(on) values, in which trapping and detrapping time constant is represented by a series of RC network. The model is simulated in PSPICE, of which the simulation results of R DS(on) values are compared and validated with the measurement when device switches in a power converter with different duty cycles and switching voltages. The results show that R DS(on) values of this device would increase due to trapping effects.

Estimating the State-of-Charge of Lithium-Ion Batteries Using an H-Infinity Observer with Consideration of the Hysteresis Characteristic

Abstract: The conventional methods used to evaluate battery state-of-charge (SOC) cannot accommodate the chemistry nonlinearities, measurement inaccuracies and parameter perturbations involved in estimation systems. In this paper, an impedance-based equivalent circuit model has been constructed with respect to a LiFePO₄ battery by approximating the electrochemical impedance spectrum (EIS) with RC circuits. The efficiencies of approximating the EIS with RC networks in different series-parallel forms are first discussed. Additionally, the typical hysteresis characteristic is modeled through an empirical approach. Subsequently, a methodology incorporating an H-infinity observer designated for open-circuit voltage (OCV) observation and a hysteresis model developed for OCV-SOC mapping is proposed. Thereafter, evaluation experiments under FUDS and UDDS test cycles are undertaken with varying temperatures and different current-sense bias. Experimental comparisons, in comparison with the EKF based method, indicate that the proposed SOC estimator is more effective and robust. Moreover, test results on a group of Li-ion batteries, from different manufacturers and of different chemistries, show that the proposed method has high generalization capability for all the three types of Li-ion batteries.

Measuring the RC time constant with Arduino

Abstract: In this work we use the Arduino UNO R3 open source hardware platform to assemble an experimental apparatus for the measurement of the time constant of an RC circuit. With adequate programming, the Arduino is used as a signal generator, a data acquisition system and a basic signal visualisation tool. Theoretical calculations are compared with direct observations from an analogue oscilloscope. Data processing and curve fitting is performed on a spreadsheet. The results obtained for the six RC test circuits are within the expected interval of values defined by the tolerance of the components. The hardware and software prove to be adequate to the proposed measurements and therefore adaptable to a laboratorial teaching and learning context.

A novel approach for electrical circuit modeling of Li-ion battery for predicting the steady-state and dynamic I–V characteristics

Abstract: A novel approach for electrical circuit modeling of Li-ion battery is proposed in this paper. The model proposed in this paper is simple, fast, not memory intensive and does not involve any look-up table. The model mimics the steady-state and dynamic behavior of battery. Internal charge distribution of the battery is modeled using two RC circuits. Self-discharge characteristic of the battery is modeled using a leakage resistance. Experimental procedure to determine the internal resistance, leakage resistance and the value of RC elements is explained in detail. The variation of parameters with state of charge (SOC) and magnitude of current is presented. The internal voltage source of the battery model varies dynamically with SOC to replicate the experimental terminal voltage characteristics of battery. The accuracy of model is validated with experimental results.

Electric Circuit Analysis

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Fluctuations of Entropy Production in Partially Masked Electric Circuits: Theoretical Analysis

Abstract: In this work we perform theoretical analysis about a coupled RC circuit with constant driven currents. Starting from stochastic differential equations, where voltages are subject to thermal noises, we derive time-correlation functions, steady-state distributions and transition probabilities of the system. The validity of the fluctuation theorem (FT) is examined for scenarios with complete and incomplete descriptions.

A Technique for Improving the Linear Operating Range for a Relative Phase Delay Capacitive Sensor Interface Circuit

Abstract: One technique for measuring an unknown sensor capacitance is using the phase delay of an RC network with a resistor and the sensor capacitor. By buffering the RC network with CMOS inverters, a square wave signal can be delayed through the circuit in proportion to the unknown capacitance. An EXOR gate can be used to compare the delayed square wave with a reference square wave to produce a pulsewidth-modulated signal where the pulsewidth is proportional to the unknown capacitance. This technique has a nearly linear response when the phase delay is small compared with the period of the square wave. However, this technique becomes severely nonlinear if the phase delay is larger than approximately one eighth of the period (45°), as the capacitor does not get fully charged or discharged every half period. To mitigate this nonlinearity, a novel resistance switching RC phase delay network is used to expand the linear range of the phase delay by accelerating the charging and discharging processes of the sensor capacitor. This approach is demonstrated using a fringing field capacitive sensor to measure the mass of added water and expands the linear operation to a phase delay to 133.56°.

Preparation of graphite conductive paint and its application to the construction of RC circuits on paper

Abstract: We describe a simple procedure for the preparation of graphite-based conductive paint and determine its basic transport properties when applied, comparing them to those of pencil strokes. Ohm's law was fulfilled on the applied paint, which makes it an ideal strategy to teach the relations between a resistor's length, width and resistance. The conductive paint was used in the construction of RC circuits on paper in a simple and didactic format. Using only the paint and a piece of cardboard, a completely functional parallel plate capacitor can be constructed with different plate geometries; in particular, we painted circular and rectangular plates. The charge and discharge cycles of the two RC circuits painted were observed in the oscilloscope. We obtained characteristic times and estimated the value of the dielectric constant of paper, which serves as a dielectric between the plates of the capacitors. We found conductive paint to be a useful and easy method to teach basic electricity and circuit concepts in fundamental courses and lab practices because it allows one to visualise properties such as the dependence of resistance and capacitance with geometric factors using a specific material.

Dynamic impedance-based modeling method for lithium battery model

Abstract: The invention relates to a dynamic impedance-based lithium battery modeling method. The method comprises the steps of building a two-order RC equivalent model of a lithium battery. The two-order RC equivalent model of the lithium battery comprises an ideal controlled voltage source which represents an open-circuit voltage of the battery, ohmic internal resistance which represents a leaping voltage generated at the moment of turning on a charging/discharging current, polarization resistance, polarization capacitance, compensation polarization resistance and compensation polarization capacitance, wherein the polarization resistance and the polarization capacitance form an RC network for simulating a polarization reaction of the lithium battery in practice; the compensation polarization resistance and the compensation polarization capacitance form the RC network for simulating compensation of the polarization reaction of the lithium battery in practice; and parameter values of the ideal controlled voltage source, the ohmic internal resistance, the polarization resistance, the polarization capacitance, the compensation polarization resistance and the compensation polarization capacitance are all changed with an SOC (State Of Charge) of the lithium battery. According to the modeling method, starting from the two-order RC equivalent circuit model, it is regarded that the impedance in the equivalent model of the lithium battery is dynamically changed with the real-time SOC of the lithium battery; a terminal voltage change characteristic of the lithium battery can be simulated; the method can be conveniently applied to simulation analysis of a micro-grid; and a dynamic impedance thought improves the accuracy of the battery model.

Rc lattice delay

Abstract: An integrated constant time delay circuit utilized in continuous-time (CT) analog-to-digital converters (ADCs) can be implemented with an RC lattice structure to provide, e.g., a passive all-pass lattice filter. Additional poles created by decoupling capacitors can be used to provide a low-pass filtering effect in some embodiments. A Resistor-Capacitor “RC” lattice structure can be an alternative to a constant-resistance Inductor-Capacitor “LC” lattice implementation. ADC architectures benefit from the RC implementation, due to its ease of impedance scaling and smaller area.

Enhanced switched capacitor filter (scf) compensation in dc-dc converters

Abstract: A system, DC-DC converter, and compensation method and circuit for a DC-DC converter are disclosed. For example, a compensation circuit for a DC-DC converter is disclosed. The compensation circuit includes an integrator circuit configured to receive and integrate a first voltage signal, a differential difference amplifier circuit coupled to the integrator circuit and configured to generate a first filter transfer function associated with the integrated first voltage signal, and a switched capacitor filter circuit coupled to the differential difference amplifier circuit and configured to generate a second filter transfer function, wherein the differential difference amplifier is further configured to output a second voltage signal responsive to the first filter transfer function and the second filter transfer function. In one implementation, the compensation circuit is a type-III switched capacitor filter (SCF) compensation circuit.

Application of direct synthesis techniques to customize filters with complex frequency response

Abstract: Summary Recently, direct synthesis techniques (DSTs) have been presented for filter synthesis. Unlike conventional synthesis techniques, DSTs derive the filtering polynomials of the filters to be synthesized directly in their own frequency domain. These filtering polynomials are real coefficient so that they might find applications in various fields. Furthermore, DSTs might be used to customize filters with a more complex frequency response, such as asymmetric frequency response or multi-band frequency response. In this paper, DSTs are compared with some well-known filter synthesis techniques. Then, the application of DSTs in the design of lumped-element LC filters, distributed-element filters, active RC filters, and infinite impulse response digital filters with complex frequency response is discussed. Some examples are presented for demonstration. Copyright © 2015 John Wiley & Sons, Ltd.

Transmitter circuit and receiver circuit for operating under low voltage

Abstract: A transmitter circuit including a pre-driver circuit configured to receive a logic signal from a logic circuit and to generate a first signal driven by a first voltage, the pre-driver circuit including a transistor having a threshold voltage equal to or lower than a threshold voltage of a transistor included in the logic circuit, and a main-driver circuit configured to receive the first signal and generate a second signal driven by a second voltage, the main-driver circuit configured to output the second signal to an input/output pad, the main-driver circuit including a transistor having a threshold voltage which is equal to or lower than the threshold voltage of the transistor included in the logic circuit may be provided.

Highly accurate capacitor-free LDO with sub-1 V −120 dB PSRR bandgap voltage reference

Abstract: A low dropout (LDO) voltage regulator operated at 5 V power supply, along with a bandgap reference (BGR) voltage circuit with high power-supply rejection ratio (PSRR) is introduced. In the suggested LDO circuit, a low-pass filter for creating a common gate to transmit supply voltage to the power transistor gate is used. During deployment of the RC filter, an artificial resistor with a value of infinity is utilised, which in addition to reduce the chip occupied area, improves the performance of the low-pass filter at frequencies close to DC, and thus improves the PSRR at these frequencies. In addition, the high PSRR of the circuit is mediated by a low-voltage current mode regulator at the heart of the bandgap circuitry, which isolates the bandgap voltage from power supply variations and noise. The isolating current mirrors create an internal regulated voltage ( V reg ) for BGR core and op-amp rather than the V DD . These current mirrors reduce the impact of supply voltage variations. The circuit topology is discussed and simulation results are provided. The LDO is also stable without an output capacitor.

Online parameter estimation/tracking for Lithium-ion battery RC model

Abstract: as a basis for Battery SOC estimation and grid integration numerical analysis, Equivalent Circuit Model (ECM) based on RC circuit topology is one of the most widely-used battery models. In the ECM model, model parameters such as internal resistance, RC circuit capacitance, and resistance are physically time-variant and depend on the battery SOC and temperature. However, as a trade-off on the gap between model complexities computation simplification, the ECM model parameters are usually considered as constant or be piece-wisely constant. In this paper, we proposed an Adaptive Thau Observer(ATO) based online parameter estimation/tracking method, which can estimate the time-variant ECM model parameter such as RC circuit capacitance in real-time. The metrics of this method only depends on measurements of battery voltage and current, which is more feasible for real-world battery SOC/SOH estimation applications comparing with existing offline battery parameter identification methods. Finally, simulation results demonstrate the effectiveness of the proposed method.

A Method for Continuous Tuning of MOSFET–RC Filters with Extended Control Range

Abstract: Abstract In this paper a tuning structure for a MOSFET?RC filters is presented. The proposed tuning structure is composed of switched resistor banks with voltage controlled transistors. The voltage controlled transistors use active feedback with extended control range for continuous filter parameter tuning, without degrading the total linearity performance of the filter. The proposed tuning structure is tested by implementing it in a second order low pass biquadratic filter cell in 65 nm CMOS technology. The designed filter has a highly reconfigurable response, ranging from Chebyshev to Bessel, a tuneable -3 dB bandwidth from 10 MHz to 100 MHz and can be used for multiple standard wireless solutions. Filter IIP3 performance is not degraded when the bandwidth is continuously tuned by 40 % with a 1 V pp input. The maximum power dissipation, including active feedback circuits, is 17.2 mW from a 1.2 V source when the filter is tuned to 100 MHz bandwidth.

Dedicated test-structures for investigation of the thermal impact of the BEOL in advanced SiGe HBTs in time and frequency domain

Abstract: This paper presents a study on the thermal impact of the back-end-of-line (BEOL) in a state-of-the-art SiGe HBT technology for high power applications. A recursive RC network is proposed to model the thermal behavior of the BEOL and is validated with measurements on dedicated test-structures in the time and frequency domain.

A dualband impedance transformer realized by fractional-order inductor and capacitor

Abstract: A novel dualband impedance transformer based on fractional-order inductor and capacitor is proposed in this paper. This transformer is designed to transfer the arbitrary frequency-dependent complex impedances sources to loads at two irrelevant frequencies with one fractional-order inductor and two fractional-order capacitors. Each fractional-order element has two parameters to be determined: the order of the element, which is a discrete number, and its coefficient, which is a continuous numbers. The standard particle swarm optimization algorithm is improved to adapt the simultaneous mixed continuous and discrete variables optimization. The continued fraction expansion method is employed to approximate the fractional-order element characteristics which response is proportional to an arbitrary order of the frequency. An RC network is built to verify the proposed method's effects after each fractional-order element synthesized by the Cauer network synthesis method. The agreement of the calculation and simulation results shows that the proposed transformer has successfully transferred the frequency-dependent complex impedances from sources to loads at two frequencies.

System, apparatus and method for adaptive tuning for wireless power transfer

Abstract: Systems, apparatuses and methods for an adaptable tuning circuit for a wireless power transfer system including an inductor and a capacitor. An input may be configured to receive alternate current (AC) power. An RC circuit may include a resistor and a supply capacitor, where a first diode is configured to be forward biased when the AC power is positive for charging the supply capacitor, and a second diode is configured to be forward biased when the AC power is negative for minimizing discharge from the supply capacitor. A tuning logic is provided for controlling power from the supply capacitor to a tuning circuit comprising a tuning capacitor and a switch arrangement, wherein the tuning circuit is configured to be parallel to the capacitor of the wireless power transfer system.

Feedback compensated oscillator

Abstract: An oscillator produces an oscillator output signal usable as a clock signal, otherwise as a frequency reference on an integrated circuit The oscillator includes an RC network with a voltage-controlled element, such as a voltage-controlled resistor, voltage-controlled capacitor or a combination including a voltage-controlled resistor and voltage-controlled capacitor Also, a tunable element having an adjustable resistance determined by a first static parameter is included in the RC network The oscillator also includes a feedback circuit which can include a frequency-to-voltage converter The feedback circuit generates a control signal for the voltage-controlled element The feedback circuit includes a feedback reference circuit having a reference output determined by a second static parameter, and a loop amplifier responsive to the reference output and the oscillator output signal

Voltage generation circuit, flash memory and semiconductor device

Abstract: A voltage generation circuit is provided to suppress the required layout of the voltage generation circuit and stabilize the output voltage thereof. [Solution] A voltage generation circuit 100 A according to the present invention includes a charge pump circuit 20 , a resistor voltage-division circuit 120 , a comparator 34 having a voltage Vm output from the resistor voltage-division circuit 120 and a reference voltage, and a control circuit 36 controlling the operation of the charge pump circuit 20 based on the comparison result of the comparator 34 . The resistor voltage-division circuit 120 includes resistors R 1 ˜R 4 connected in series between an output node N OUT and a ground and generates the voltage Vm at a voltage-division node N R in response to an output voltage V OUT . The resistor voltage-division circuit 120 further includes a parasitic capacitor Cp to capacitively couple the resistors R 1 , R 2 , R 3 and R 4 to the output node N OUT .

Integrated calibration circuit and a method for calibration of a filter circuit

Abstract: A calibration circuit and a method for calibrating a RC circuit, such as a high-pass filter, of an integrated circuit are provided. The calibration circuit comprises a filter arrangement having tuneable filter for filtering an input signal having a predetermined frequency. The filter comprises tuneable resistor elements, a saturation detector for detecting saturation and non-saturation of the tuneable filter by comparing a comparison voltage with the signal voltage of the filtered input signal, calibration control logic for providing incrementing and decrementing counter signals. The calibration circuit sets the comparison voltage to a first threshold voltage provides iteratively the incrementing counter signal to the filter until saturation is detected reduces the comparison voltage to a predetermined second threshold voltage after saturation is detected, the second threshold voltage being a lower value than the first threshold voltage, and provides the decrementing counter signal to the filter until non-saturation is detected.

Realization of 4D lattice-ladder digital filters

Abstract: A circuit realization is presented for four-dimensional (4D) lattice-ladder discrete filters. The proposed 4D circuit realization requires, for its implementation, a minimum number of delay elements. Further, the dimension of the state-vector, of the derived 4D state-space model, is minimal and its 4D transfer function is characterized by the all-pass property. A step-by-step low-order example is provided to demonstrate the proposed minimality of both, circuit, and state-space realizations. An educational conjointment of 4D lattice filters with lower dimension filters (2D, 1D), is imparted.