Showing papers on "RC circuit published in 2010"

Flashover process and frequency analysis of the leakage current on insulator model under non-uniform pollution conditions

Abstract: In this paper, we present results dealing with the non-uniform pollution carried out under 50 Hz applied voltage on a plane model simulating the 1512 L outdoor insulator largely used by the Algerian Company of Gas and Electric Power (SONELGAZ). Many configurations in non-uniform pollution are studied in the ENP's (Ecole Nationale Polytechnique d'Alger) High Voltage Laboratory in order to analyze the impact of polluted layer distribution on the insulator dielectric performances. The polluted solution has a conductivity of 1.2 mS/cm obtained with distilled water and NaCl. Our investigations are particularly focused on the on line monitoring of both position and width of the contaminated layer. The flashover voltage and the leakage current magnitude have been investigated in order to study the flashover process on this insulating surface. A video apparatus is used to reflect the parallel discharges behavior, appearing when the polluted layer reaches a critical width. Phase angle values between applied voltage and leakage current (LC) signals at the fundamental frequency (50 Hz) are calculated using the Fast Fourier Transform (FFT) spectral analysis. Phase angle measurements indicate that the equivalent impedance of the insulator behaves like RC circuit with a high capacitive effect engendered by the pre-established clean band. This effect decreases when electric discharges occur at a particular voltage level. The Discrete Wavelet Transform (DWT) is adopted for the leakage current decomposition in several time-frequency bands. The STD-MRA (Standard deviation-Multi Resolution Analysis) of these frequency bands is calculated and is employed to choose the most interesting details that detect both position and width increasing of the conducting layer. Reported results show that the pollution surface state and the severity of this conducting layer deposited on insulator surface could be identified from the STD-MRA representation of leakage current frequency bands. It was shown that the high frequency band of the leakage current increases before the final flashover when the polluted layer is located in the middle of the plane model. It was established that a good correlation has been found between the insulator state surface and details of the leakage current obtained through the DWT decomposition. In fact, these details provide relevant information on both position and width of the polluted layer nonuniformly distributed on the insulator surface.

Power Efficient Gigabit Communication Over Capacitively Driven RC-Limited On-Chip Interconnects

Abstract: This paper presents a set of circuit techniques to achieve high data rate point-to-point communication over long on-chip RC-limited wire-pairs. The ideal line termination impedances for a flat transfer function with linear phase (pure delay) are derived, using an s-parameter wire-pair model. It is shown that a driver with series capacitance on the one hand and a resistive load on the other, are fair approximations of these ideal terminations in the frequency range of interest. From a perspective of power efficiency, a capacitive driver is preferred, as the series capacitance reduces the voltage swing along the line which reduces dynamic power consumption. To reduce cross-talk and maintain data integrity, parallel differential interconnects with alternatingly one or two twists are used. In combination with a low offset dynamic sense amplifier at the receiver, and a low-power decision feedback equalization technique with analog feedback, gigabit communication is demonstrated at very low power consumption. A point-to-point link on a 90 nm CMOS test chip achieves 2 Gb/s over 10 mm long interconnects, while consuming 0.28 pJ/bit corresponding to 28 fJ/bit/mm, which is much lower than competing designs.

New CMOS DVCC realization and applications to instrumentation amplifier and active-RC filters

Abstract: This paper presents a novel CMOS differential voltage current conveyor (DVCC) based on a wide linear range transconductor with common mode detection. The DVCC exhibits a wide dynamic input range of ± 0.9 V . It is used to realize an instrumentation amplifier, a multiple input single output filter, and a single input multiple output universal filter. PSPICE simulations of the proposed DVCC and its based applications are given using 0.25 μ m CMOS technology from TMSC MOSIS and dual supply voltages ± 1.5 V .

Wideband Microwave Absorber Based on a Two-Dimensional Periodic Array of Microstrip Lines

Abstract: The modeling and design is presented of a new kind of circuit analogue absorber, which intercepts the electromagnetic waves through a two-dimensional periodic array of microstrip lines loaded with lumped circuit elements. For a plane wave incidence of polarization perpendicular to the strips, virtual magnetic walls are formed between the strips, and the geometry can be divided into many identical unit-cells. We first study the propagation characteristics of the unit-cell using the singular integral equation method. An RC network is then proposed to match this array with the free space and to dissipate the intercepted energy over a wide frequency range. The complete design procedure is explained through a design example that exhibits a bandwidth of 113% while the absorber thickness is less than 10% of the free space wavelength at the lowest operating frequency.

System and method for high precision current sensing

Abstract: An apparatus for sensing an input current through an inductor includes an RC circuit connected in parallel with the inductor across first and second input pins of an integrated circuit. A voltage monitoring circuit monitors a first voltage at the first input pin of the integrated circuit and monitors a second voltage at the second input pin of the integrated circuit. An op-amp compares the first voltage with the second voltage and generates a control output responsive to the comparison. A current sink circuit responsive to the indication controls the first voltage to substantially equal the second voltage.

An Energy-Efficient Equalized Transceiver for RC-Dominant Channels

Abstract: This work describes the architecture and circuit implementation of a high-data-rate, energy-efficient equalized transceiver for high-loss dispersive channels, such as RC-limited on-chip interconnects or silicon-carrier packaging modules. The charge-injection transmitter directly conducts pre-emphasis current from the supply into the channel, eliminating the power overhead of analog current subtraction in conventional transmit pre-emphasis, while significantly relaxing the driver coefficient accuracy requirements. The transmitter utilizes a power efficient non-linear driver by compensating non-linearity with pre-distorted equalization coefficients. A trans-impedance amplifier at the receiver achieves low static power consumption, large signal amplitude, and high bandwidth by mitigating limitations of purely-resistive termination. A test chip is fabricated in 90-nm bulk CMOS technology and tested over a 10-mm, 2- μm pitched on-chip differential wire. The transceiver consumes 0.37-0.63 pJ/b with 4-6 Gb/s/ch.

Evaluating Energy Storage Efficiency by Modeling the Voltage and Temperature Dependency in EDLC Electrical Characteristics

Abstract: This study characterizes and models the temperature and charge voltage dependency in the electrical characteristics of a packed electric double layer capacitor (EDLC). The characterized results indicate that the frequency response of the terminal impedance in a packed EDLC varies with the charge voltage and temperature. The latter can be attributed mainly to the temperature change of the resistive component because the thermal sensitivity of the capacitive component is low, whereas the resistive component increases as the temperature drops. A multistage RC equivalent circuit model is developed, and three stages are determined to be adequate to reduce the model error for the studied EDLC. The charge voltage dependency in the capacitance of the extracted equivalent circuit is modeled by the physics-based Stern's model. The temperature dependency of the internal resistance is modeled by the quadratic function of temperature. The large signal response of the proposed model is verified with charge/discharge experiments at various temperatures. The proposed EDLC model suitably expresses the time response of the terminal voltage and current, can estimate the charged and discharged electrical power and energy of the EDLC, and explains the degradation of energy efficiency at low temperature.

Identification of dynamic model parameters for lithium-ion batteries used in hybrid electric vehicles

Abstract: This paper presents an electrical equivalent circuit model for lithium-ion batteries used for hybrid electric vehicles (HEV) The model has two RC networks characterizing battery activation and concentration polarization process The parameters of the model are identified using combined experimental and Extended Kalman Filter (EKF) recursive methods The open-circuit voltage and ohmic resistance of the battery are directly measured and calculated from experimental measurements, respectively The rest of the coupled dynamic parameters, ie the RC network parameters, are estimated using the EKF method Experimental and simulation results are presented to demonstrate the efficacy of the proposed circuit model and parameter identification techniques for simulating battery dynamics

Self-adaptive current-mode-control circuit for a switching regulator

Abstract: A current-mode-control circuit for a switching regulator is provided. The circuit includes a first transistor coupled to a power supply voltage, a second transistor, and an inductor. The circuit further includes a slope compensation generation circuit coupled to the output of the current control circuit through a feedback loop, the slope compensation generation circuit generating a slope compensation current related to the output voltage, an inductor current sensing circuit coupled to the first transistor and the second transistor, and configured to calculate a current through the inductor and output a inductor sense current, and a pulse-width modulation control circuit coupled to the slope generation circuit and the inductor current sense circuit, the pulse-width modulation control circuit receiving the output of the current control circuit, the slope compensation current and the inductor sense current as inputs.

Drive circuit for realizing accurate constant current of multiple LEDs

Abstract: The invention discloses a drive circuit for realizing the accurate constant current of multiple LEDs, which comprises a high-frequency impulse alternating current power supply, a rectification filter circuit, a blocking condenser C1 and two ways of LED loads, and is characterized in that the rectification filter circuit comprises two independent half-wave rectifying circuits, a filter capacitor C2 and a filter capacitor C3; and the two independent half-wave rectifying circuits respectively supply power for the two ways of LED loads, the filter capacitor C2 and the filter capacitor C3 are respectively connected on the two ends of the two ways of LED loads in parallel, and the blocking condenser C1 is connected with the input end of the rectification filter circuit in series. The invention has the following beneficial effects that: 1, a first class transformation circuit is adopted to realize the uniform current of the loads between multiple LEDs, the cost is low, additional control circuits do not needed, and the reliability is high; 2, the uniform current has high accuracy and cannot be influenced by the differential pressure of the LED loads; and 3, the blocking condenser can realize high efficiency of the uniform current, i.e. when the differential pressure of the two ways of LEDs is larger, the loss to realize uniform current is smaller.

A new visit to an old problem in switched-capacitor converters

Abstract: The energy-efficiency issue of the switched-capacitor converters is still a highly controversial topic that requires a more in-depth exploration. This paper will address the issue by dissecting the analysis of the entire efficiency problem into two parts. In the first part, the efficiency analysis of charging the capacitor of an RC circuit under different aspects (partial charging, full charging, at zero capacitor voltage, at non-zero capacitor voltage, etc.) will be conducted. In the second part, the efficiency analysis of discharging the capacitor of an RC circuit with resistive and capacitive loads will be covered. A complete evaluation of the overall efficiency is then performed in terms of both the charging and discharging efficiencies of the capacitor. Additionally, it is shown in this paper that the claim that quasi-switched-capacitor converters are more lossy than switched-capacitor converters is a common misconception.

Ultra low power RC oscillator for system wake-up using highly precise auto-calibration technique

Abstract: An ultra low power RC oscillator for system wake-up is implemented using 0.18um CMOS process. The modern mobile systems need system clock which consumes low power and thus saves limited battery power in order to wake up from sleep-mode. A RC oscillator operates in the subthreshold region to reduce current consumption. The output frequency of RC oscillator is very weakly dependent on process and temperature variation using auto-calibration. This RC oscillator is featured as follows: the current consumption is 0.2 μA the supply voltage is 1.8V; the output frequency is 31.25 KHz with 1.52(Relative 3σ)% accuracy after calibration; it has only 0.4%/°C temperature coefficient; its size is 190 um } 80 um exclude bonding pad.

Signal transmission through LC resonant circuits

Abstract: An embodiment of an electronic system includes a first electronic circuit and a second electronic circuit. The electronic system further includes a resonant LC circuit having a resonance frequency for coupling the first electronic circuit and the second electronic circuit; each electronic circuit includes functional means for providing a signal at the resonance frequency to be transmitted to the other electronic circuit through the LC circuit and/or for receiving the signal from the other electronic circuit. The LC circuit also include capacitor means having at least one first capacitor plate included in the first electronic circuit and at least one second capacitor plate included in the second electronic circuit. The LC circuit further includes first inductor means included in the first electronic circuit and/or second inductor means included in the second electronic circuit. The at least one capacitor plate of each electronic circuit is coupled with the corresponding functional means through the possible corresponding inductor means.

Combined balun and impedance matching circuit

Abstract: An apparatus for providing impedance matching between a single-ended circuit and a differential circuit includes first and second capacitors and first and second inductors. The first capacitor is connected between an input/output of the single-ended circuit and a first differential input/output of the differential circuit. The first inductor is connected between the input/output of the single-ended circuit and a second differential input/output of the differential circuit. The second capacitor is connected between the second differential input/output of the differential circuit and ground. The second inductor is connected between the first differential input/output of the differential circuit and the second differential input/output of the differential circuit.

A Tunable Ionic Liquid Based RC Filter Using Electrowetting: A New Concept

Abstract: RC filters are used to discriminate unwanted frequency elements of a specific signal. Here we report a new concept for a tunable RC filter. The concept was demonstrated by developing a tunable RC filter “consisting of an ionic liquid drop placed on a dielectric layer.” Cut-off frequency of the filter can be altered and controlled by changing the drop shape via electrowetting. The dielectric layer and the solid−liquid interface behave as serially connected capacitors, where the total capacitance is a function of drop shape (or contact angle). The drop shape and hence the total capacitance can be instantly controlled by electrowetting. The change in the capacitance will change the cutoff frequency of the filter. For a 5 μL ionic liquid drop, the achieved “tunability range” was 4.5−9.8 kHz. This demonstrates that the new concept is attainable. This RC filter system could potentially be used as a detecting technique.

Constant current control circuit with multiple outputs for led driver

Abstract: A constant current control circuit with multiple outputs for a LED driver, the circuit including a single-output constant current power supply, and multiple output circuits, each output circuit comprising a current sharing circuit, a current sharing control circuit and a LED load. The LED load and the current sharing circuit are in series and form a series loop with a first terminal and a second terminal of the series loop connected to a first output terminal and a second output terminal of the constant current power supply.

Differential amplifier circuit and wireless receiving apparatus

Abstract: A differential amplifier circuit includes a source follower circuit to which is input one of the differential signals and a common source circuit that is connected in series with the source follower circuit and to which is input the other of the differential signals.

Grid interconnection inverter and grid interconnection device

Abstract: A grid interconnection inverter includes: a voltage conversion circuit configured to output an intermediate voltage by raising or lowering an input voltage from a direct current power source; and a waveform conversion circuit configured to convert the intermediate voltage into a alternating current power in a sine waveform shape. The voltage conversion circuit includes: a positive-side circuit arranged on a positive-side line between a positive polarity of the direct current power source and the waveform conversion circuit; and a negative-side circuit arranged on a negative-side line between a negative polarity of the direct current power source and the waveform conversion circuit. The positive-side circuit and the negative-side circuit have circuit configurations symmetric to each other.

Semiconductor integrated circuit device and IC card mounting same

Abstract: In an IC card, even when undershoot or overshoot which occurs upon an amplitude change by communication data is large, the change is accurately detected. A semiconductor device has antenna terminals, a power supply circuit for generating power supply voltage from an AC signal supplied to the antenna terminals, and a receiver circuit for demodulating an information signal superimposed on the AC signal. The receiver circuit includes a rectifier circuit, a filter circuit, a capacitor, an amplifier, a feedback path, a switch circuit, a binarizing circuit, and a control circuit. An output of the amplifier is transmitted to an inverting input terminal thereof, and the switch circuit is controlled by an output of the control circuit. In a predetermined period since level changes of an output of the binarizing circuit, the switch circuit is controlled to an off state by the output of the control circuit.

A test concept for circuit level aging demonstrated by a differential amplifier

Abstract: In this work a general concept for accelerated aging of linear analog circuit blocks is proposed. Due to the interaction of diverse aging mechanisms, circuit behavior in an arbitrary effect accelerated stress setup may show large deviation to the aging under nominal circuit conditions. The proposed analytical small signal analysis proves to be a fast and easy way to obtain the contributions of all degrading transistors with respect to the output monitor of the circuit. Circuit aging simulations over temperature rise as well as supply and input voltage scaling show that single effect acceleration varies significantly between the involved mechanisms. This causes deviations in the aging output monitor compared to the aging under nominal circuit conditions. Based on these findings an accelerated circuit level aging test concept - applicable to linear circuits - is developed and evaluated for the example of a two-stage differential amplifier.

Linearity improvement of cascode CMOS LNA using a diode connected NMOS transistor with a parallel RC circuit

Abstract: A fully integrated 5.5GHz high-linearity low noise amplifler (LNA) using post-linearization technique, implemented in a 0.18"m RF CMOS technology, is demonstrated. The proposed technique adopts an additional folded diode with a parallel RC circuit as an intermodulation distortion (IMD) sinker. The proposed LNA not only achieves high linearity, but also minimizes the degradation of gain, noise flgure (NF) and power consumption. The LNA achieves an input third-order intercept point (IIP3) of +8:33dBm, a power gain of 10.02dB, and a NF of 3.05dB at 5.5GHz biased at 6mA from a 1.8V power supply.

Simple RC low pass filter circuit fabricated by unmodified desktop inkjet printer

Abstract: In this work, we present resistor-capacitor circuit (RC circuit) or simple RC low pass filter circuit was fabricated by using simple inkjet printing technique. A conductive polymer, Poly (3, 4-ethylenedioxythiophene)/poly-styrene-sulfonic acid (PEDOT/PSS) was used as a resistive component and electrode material for the capacitor. Commercially available Ethyl-2-cyanoacrylate was applied as the dielectric of the capacitor. The device was inkjet printed by using a normal desktop printer CANON IP 4500. It was shown that the cut-off frequency of the device could be tuned to 10 kHz. The finding indicate the practical use of PEDOT/PSS RC low pass filter in flex sensor.

Characterization of the thermal impedance of high–power LED assembly based on innovative printed circuit board technology

Abstract: We present a method of dynamic thermal characterization of an entire test assembly, consisting of high-power Light Emitting Diodes (LED) and a printed circuit board (PCB) by measuring the thermal response on a power-on-step function and describing the thermal impedance with a Foster RC network. For this purpose, we record temporal temperature functions on test assemblies during pulse load experiments under defined initial and boundary conditions (the assemblies were horizontally positioned under free air in a test chamber), establish the LEDs' junction temperature-versus-time functions for known power functions and calibrate the parameters of the Foster RC network. Moreover, we reveal connections between design parameters (conductor layout, thermal via geometry, and PCB material) and the thermal impedance of the assembly. The method allows the user to predict the LED's junction temperature as transient thermal response on an arbitrary pulse load function (as e.g. flashes with different intensity, duration and repetition rate) with low effort.

Selection of Parameters of External Electric Circuit for Control of Dynamic Flexibility of a Mechatronic System

Abstract: This paper deals with the analysis of mechatronic systems including piezoelectric materials used as sensors or actuators for stabilization and damping of mechanical vibration. This work presents the analysis of the flexural vibrating one-dimensional mechatronic system – a cantilever beam and the piezoelectric transducer bonded on the beam surface by means of a glue layer. The external RC circuit is connected to the transducer clamps. Dynamic equations of motion of the considered mechatronic system were written down using the discrete-continuous mathematical model, taking into consideration the influence of the connection layer and the external electric circuit. Dynamic flexibility of the mechatronic system was assigned on the basis of the approximate Galerkin method.

Method for in situ battery diagnostic by electrochemical impedance spectroscopy

Abstract: The invention is a method for estimating the internal state of a system for the electrochemical storage of electrical energy, such as a battery. For various internal states of batteries of the same type as a battery being analysed, impedance measurements are carried out by adding an electrical signal to the current passing through the batteries. Then, an RC circuit is used to model the impedances. Next, a relationship is calibrated between the SoC (and/or the SoH) and the parameters of the RC circuit using multivariate statistical analysis. A measurement of the impedance of the battery under analysis is carried out which is modeled using the RC circuit. Finally, the relationship of the equivalent electric circuit defined for the battery being analysed is used to estimate the internal state of that battery.

An explicit model for delay and rise time for distributed RC on-chip VLSI interconnect

Abstract: In this paper, simple explicit delay and rise time expressions for uniformly distributed RC on-chip interconnect line are derived based on Elmore's approximations. Here, an n-cell RC ladder network with capacitive load is used. Transfer function for the n-cell RC ladder network is obtained by using the transmission line parameter matrix for each cell. In order to deduce the transfer function, the transmission line is modeled by a lumped parameter network. From this transfer function, explicit delay and rise time expressions are derived by using Elmore's definitions. The calculated delay and rise times by our proposed closed form expressions are compared with the results obtained by SPICE simulation for n=2, 3, 4, 5, 6, 7 cell ladder networks with capacitive load.

Current reference circuit

Abstract: A current reference circuit includes a proportional-to-absolute temperature (PTAT) current generator, a band-gap reference circuit and a current replication circuit. The PTAT generator generates a PTAT current. The band-gap reference circuit generates a reference voltage based on the PTAT current and generates a second current by cancelling a first current from the PTAT current. The first current has a zero temperature coefficient and the second current has a positive temperature coefficient. The current replication circuit replicates the first current based on the PTAT current and the second current.

Switched mode voltage regulator and method of operation

Abstract: A voltage regulator includes a transistor, a comparator, and a compensation circuit. The comparator has a first input terminal coupled to receive a clock signal, a second input terminal, and an output terminal coupled to a control electrode of the transistor. The compensation circuit has a first input terminal coupled to receive a reference voltage, a second input terminal coupled to the output terminal of the voltage regulator, and an output terminal coupled to the second input terminal of the comparator. The compensation circuit has a filter circuit. The filter circuit has a first RC time constant during startup of the voltage regulator, and the filter circuit has a second RC time constant during normal operation. Changing the RC time constant for startup prevents an overshoot of an output voltage of the voltage regulator.

High-speed analog photon counter and method

Abstract: A high speed analog photon counter and method is provided In one aspect, the method includes delivering an electric charge to a circuit of the high speed analog photon counter through a current source of the circuit The method also includes accumulating the electric charge in a capacitor of the circuit electrically coupled to the current source The method further includes comparing the electric charge accumulated in the capacitor of the circuit with a reference voltage through a comparator of the circuit electrically coupled to an output of the capacitor The output of the capacitor of the circuit is coupled to an input of the comparator of the circuit, and the reference voltage is coupled to another input of the comparator of the circuit The method furthermore includes resetting the capacitor of the circuit when the electric charge accumulated in the capacitor of the circuit matches the reference voltage