Showing papers on "RLC circuit published in 1991"

RICE: Rapid interconnect circuit evaluator

Abstract: This paper describes RICE, an RLC interconnect evaluation tool based upon the moment-matching technique of Asymptotic Waveform Evaluation (AWE). The RLC circuit moments are calculated by a path-tracing algorithm which enables the analysis of large interconnect models several thousand times faster than a circuit simulation while requiring 5 to 10 times less memory. RICE also includes a new approach for determining the circuit dominant time-constants which avoids the inherent instability problems associated with moment matching methods in general.

A fast-response high power factor converter with a single power stage

Abstract: An offline switching converter which operates with high input power factor while maintaining fast transient response at its output is described. A single power stage with dual output produces both the desired DC output and a boosting supply in series with the input. The resonant boosting supply at the input is controlled by frequency modulation of the power stage, while the desired DC output is PWM controlled. Since both the input boost supply and the output supply can be controlled independently, a fast transient response can be maintained at both the input (for active current wave-shaping), and at the output (for good output regulation). In addition, even without active control of the boost supply, a reasonably good input current waveshape results due to the natural gain characteristics of the boost resonant circuit. Zero voltage switching is maintained, allowing the circuit to be designed at high frequency to reduce size and cost, and increase performance. >

Portable field-programmable detection microchip

Abstract: A read/write device includes a transmitter for producing an RF signal and a modulator coupled to said transmitter for modulating the RF signal and, finally a data receiver for receiving RF data signals from a portable microchip. The microchip includes a resonant circuit tuned to the RF frequency of the read/write transmitter and a receiver that is coupled to the resonant circuit for detecting the RF signal. There is also provided a charging capacitor capable of storing the electrical energy from the RF signal so that the microchip can be powered during pulse pauses of the RF signal. The microchip includes a memory circuit for storing the identification code of the microchip, and a code generator that is coupled to the memory circuit for generating an RF signal that is modulated with the identification data. A switching element that couples the resonant circuit to the code generator de-tunes the resonant circuit when the identification data is transmitted back to the read/write device. The same resonant circuit also serves to field program the memory circuit of the microchip by receiving pulse pause modulation signals (PPM) of the RF carrier signal thus allowing the identification code of the microchip to be altered by the read/write device.

The auxiliary quasi-resonant DC link inverter

Abstract: A quasi-resonant DC link converter topology is proposed. The basic topology of the auxiliary quasi-resonant DC link (AQRDCL) is derived from the auxiliary resonant commutated pole (ARCP) converter and is closely related to the active clamped resonant DC link (ACRDCL) circuit. The operation and gating control strategy of the AQRDCL converter, which ensures zero voltage switching of all inverter switches and zero current switching of the auxiliary switches, is presented. The proposed circuit utilizes auxiliary switches to trigger the LC resonance of the DC link to create a zero voltage switching opportunity for the inverter switches. The waveform quality and the performance of the AQRDCL inverter, which has PWM capability, is compared with the DPM strategy of the ACRDCL inverter. >

Class D voltage-switching MOSFET power amplifier

Abstract: An analysis of a class D voltage-switching tuned power amplifier is given, along with experimental results. Analytical equations are derived for performance parameters at any operating frequency normalised with respect to the resonant frequency and at any load resistance normalised with respect to the characteristic impedance of the resonant circuit. The analysis is carried out under the high loaded quality factor assumption, using Fourier series techniques. The behaviour of power MOSFETs in class D circuits for both capacitive and inductive loads is discussed in detail. It is shown that the operation above the resonant frequency (an inductive load) is preferred. The theoretical results were in good agreement with measured circuit performance parameters. The equations provide easy-to-use design tools, which can find a broad application, e.g. in designing DC/DC resonant converters and DC/AC inverters.

Method for controlling a power converter using an auxiliary resonant commutation circuit.

Abstract: A method for controlling a power converter and an associated auxiliary commutation circuit ensures soft-switching of all switching devices employed therein. Such a power converter includes an inverter with at least two main switching devices per phase. Across each main switching device are connected an antiparallel diode and a relatively large snubber capacitor. The auxiliary resonant commutation circuit comprises two antiparallel-coupled auxiliary switching devices coupled in series with a resonant circuit including an inductor and the snubber capacitors. The gating and conduction times of the main and auxiliary switching devices are controlled so as to add boosting energy to the resonant operation, thus ensuring that the inverter output voltage at least reaches the positive and negative inverter rail voltages during each resonant commutation cycle. As a result, the control achieves commutation of the converter pole with substantially no switching losses.

Asymmetrical pulse width modulated resonant DC/DC converter

Abstract: New topologies for pulse width modulated resonant DC/DC converters are disclosed. The converters include a bridged chopper to convert the DC input to a high frequency AC which in turn is fed to a high frequency transformer whose secondary AC is rectified and filtered to produce a stable DC output. The bridged chopper has at least two semiconductor switches which alternately conduct. The duty cycles of the conduction of the switches are complementary with one another and adjustable to control the stable DC output. A resonant circuit is connected between the chopper and the high frequency transformer and contains a series capacitor, and a series or parallel inductor depending upon the preferred embodiment.

Power supply for an ozone generator with a bridge inverter

Abstract: A full bridge switching power supply is coupled to an ozonator load via a series resonant circuit having a resonant frequency above the switching frequency Power output is controlled by varying the duration of the times when diagonal switches are conducting, and the output voltage has a longer rise time than fall time due to there being intervals between the conduction periods of diagonal switches during which one of the switches is turned on to permit resonant current flow The driving voltages for attaining this action are symmetrical rectangular waves of identical shape having different phases that are derived from out of phase pulses where width is varied by the timing of their trailing edges

Overshoot-controlled RLC interconnections

Abstract: How overshoot in the step response of a circuit involving an RLC line can be controlled using a combination of driver and line resistance that depends on the load capacitance is shown. The no-peak condition or its equivalent is used to relate line parameters to the driver and load impedances. This no-peak condition generalizes the impedance matching customarily used for lossless lines, i.e. it provides an alternative to the traditional choice R/sub D/= square root L/C. The results allow improved circuit response without risk of overshoot, for example, by reduction of driver resistance below square root L/C for cases where line resistance is unavoidable and/or where load capacitance is not negligible compared to line capacitance. The algebraic formulas derived are more effective than case-by-case numerical simulations for analyzing scaling and technology issues, whether on-chip, or at the packaging, board, or system levels. >

Paper thickness detecting apparatus having a resonator with a resonance point set by a capacitance detecting unit

Abstract: Apparatus for detecting thickness which includes an electrode detecting unit including a ground electrode and a detecting electrode The electrodes oppose each other along a paper path An oscillating circuit provides an oscillation frequency signal A resonant circuit, having a resonator independent of the oscillating circuit, has a resonance point which changes in accordance with a change in electro-static capacitance corresponding to a change in paper thickness detected by the electrode detecting unit A resonant circuit outputs a detection signal corresponding to the change in resonance point By analyzing this detecting signal, a state of two sheets of paper passing through the path is detected as a change in paper thickness

Antenna for tire monitoring device

Abstract: An antenna to be used with transponder type devices. The antenna includes an inductance and a capacitor forming a resonant circuit. To avoid any heating and to have a sufficiently broad passband or operating range, there is in parallel with the inductance, a branch comprising two Zener diodes connected in opposite directions. Any nonlinear damping arrangement having an equivalent effect may be used in the branch.

Flip-chip mmic oscillator assembly with off-chip coplanar waveguide resonant inductor

Abstract: A coplanar waveguide based microwave monolithic integrated circuit (MMIC) oscillator chip (14) having an active oscillator element (16) and a resonant capacitor (18) formed thereon is flip-chip mounted on a dielectric substrate (12). A resonant inductor (22) is formed on the substrate (12) and interconnected with the resonant capacitor (18) to form a high Q-factor resonant circuit for the oscillator (10). The resonant inductor (22) includes a shorted coplanar waveguide section (24) consisting of first and second ground strips (24b,24c), and a conductor strip (24a) extending between the first and second ground strips (24b,24c) in parallel relation thereto and being separated therefrom by first and second spaces (26a,26b) respectively. A shorting strip (24d) electrically interconnects adjacent ends of the conductor strip (24a) and first and second ground strips (24b,24c) respectively. A dielectric film (34) may be formed over at least adjacent portions of the conductor strip (24 a) and first and second ground strips (24b,24c). The resonant inductor (22) is adjusted to provide a predetermined resonant frequency for the oscillator (10) by using a laser (40) to remove part of the dielectric film (34) in the first and second spaces (26a,26b) for fine adjustment, and/or to remove part of the shorting strip (24d) at the ends of the first and second spaces (26a,26b) for coarse adjustment.

Generalized in-plane circuit averaging

Abstract: The authors present an unified approach to in-place circuit averaging that is applicable to resonant-type circuits as well as pulse-width-modulated (PWM) circuits. The approach allows the refinement of an averaged circuit model to obtain an arbitrary degree of accuracy. In the context of a particular circuit, an approximate averaged representation for each branch variable consists of a subset of the Fourier coefficients (index-k averages). The selection of this subset is determined by the dominant harmonic content of the circuit waveforms. For instance, in a series resonant DC-DC converter, the index-1 averages would be selected for the resonant tank variables, whereas the index-0 averages would be selected for the load side elements. In a PWM converter one would normally use the index-0 averages to obtain a low-frequency approximate model. These models can then be refined by including additional coefficients. This procedure is illustrated for a PWM up-down converter and for a DC-DC series resonant converter. >

Temperature detector and a temperature compensated oscillator using the temperature detector

Abstract: A temperature compensated oscillator and a temperature detector have a temperature sensor having a single case in which a pair of AT cut crystal resonator having substantially the same natural oscillation frequency and different cut angles from each other are accommodated. The crystal resonators each constitutes the resonance circuit of respective one of two oscillation circuits. A difference in frequency between the output frequencies of the oscillation circuits is representative of a detected temperature.

Switching power source

Abstract: A resonant type switching power source implementing zero voltage switching on the basis of the resonance between an inductor and a capacitor. A main switch is connected to the primary side of a main transformer. A pulse width control circuit generates a control signal for varying the turn-on time of the main switch until the output voltage of the secondary side of the tranformer being fed back reaches a predetermined value. A resonance capacitor is connected in parallel with the main switch. When the terminal voltage of the capacitor crosses zero potential toward the negative side, the pulse width control circuit delivers an ON command to the main switch. Alternatively, the ON control over the main switch may begin at a time a predetermined period of time later than the time for turning on the resonant circuit.

Modeling the dc superconducting quantum interference device coupled to the multiturn input coil

Abstract: In order to study the effect of a multiturn input coil on superconducting quantum interference device (SQUID) characteristics, the radio frequency (rf) properties of the coupling circuit between the SQUID coil and the input coil are studied. For the measurement of rf properties of the coupling circuit, the so‐called expanded model of the coupling circuit using normal metals was adopted, which is shown to be very useful for this purpose. It is shown that the SQUID coil cannot be expressed by a simple inductance when the SQUID coil is coupled to the input coil, i.e., many resonant structures are observed in rf properties of the coupling circuit. It is also shown that the damping resistance is useful in suppressing the resonant structures. Using the experimental results, a circuit model of the SQUID coupled to the multiturn input coil is proposed.

Method of producing electrical resonant circuits, specifically resonance labels

Abstract: By means of this invention electrical resonant circuits, specifically resonance labels having a capacitor and a coil on a dielectric are produced for reliable deactivation by means of an electrical discharge between the capacitor surfaces. Heretofore aluminum threads produced from the material of the capacitor surfaces is not supported in place so that it can break with handling and vibration and cause reactivated of the resonant circuit leading to a false alarm in the safety system. According to this method a plurality of conductive bodies of a size in the micron range, e.g. copper dust is introduced in the dielectric so that a spark from discharge of a capacitor will cause an electrically conducting connection between the capacitor surfaces, which is embedded in a thread like shape in the dielectric. By using copper dust, an alloy is formed with the aluminum which evaporates during the spark discharge such that the thread produced has a substantially larger ductility than pure aluminum.

Resonant inverter circuitry for effecting fundamental or harmonic resonance mode starting of a gas discharge lamp

Abstract: The invention relates to an inverter powering a lamp that uses a switch to vary the resonance of the resonance circuit for starting and for operating.

Low-loss resonant circuit for capacitance driver

Abstract: A fast lossless power MOSFET gate capacitance (C) driver uses a 3-winding transformer (T) to secure clamping (N, Vc, D) of the turn-on voltage level by coupling of the winding (N1) in the capacitance charging circuit to that (N) across the clamping potential (Vc) in series with a clamping diode (D). A similarly coupled winding (N2) in the discharging circuit can ensure clamping of the turn-off level, both rise and fall starting at zero current and being sinusoidal. Alternatively, a high Q constant current charge can be used with the charging circuit switch (S1) DC isolated from the capacitance and using the magnetising current built up in the transformer. Instead of clamping the turn-off level, the discharging circuit can be switched (S2) during magnetising current build-up (S1) using a separate inductance to reverse the capacitance voltage in a half-wave resonant circuit.

Electro-optical light modulator driven by a resonant electrical circuit

Abstract: A crystal exhibiting a variable index of refraction in response to a voltage applied across it is driven from a lower voltage signal generator through a passive resonant circuit. The resonant frequency of the circuit is tunable by hand in order to maximize the voltage applied to the crystal from a low voltage signal generator. The impedance of the circuit is also hand adjustable in order to match that of the signal generator. The crystal and driving circuit are packaged together in a single enclosure having optically transparent windows allowing a laser beam to pass through the crystal and be modulated by it according to the frequency of the signal generator.

High speed frequency agile FSK modulator

Abstract: A modulation circuit that is particularly suited for a communication modem and provides for each of the channels precise carrier mark and space frequencies generated in response to external signals from an FSK communication station. The modulation circuit includes first and second frequency controlling circuits arranged with an inductor to form a resonant circuit of a voltage variable oscillator. The modulation circuit further includes a feedback control network and a voltage-frequency control adjustment circuit. The feedback control network generates a loop error signal applied to both frequency controlling circuits. The voltage-frequency control adjustment circuit generates a voltage-frequency adjustment control signal and has a switching circuit responsive to the external signals. The voltage-frequency control adjustment circuit includes an inverting network and a bias network. The inverting network receives the loop error signal and provides, when in an operative state, an output signal that is phase shifted by a predetermined amount from the loop error signal. The bias network is connected between the output of the inverting network and the second frequency controlling circuit and controls the operative and non-operative state of the inverting network. The combined operation of the inverter network and the bias network generates carrier frequencies that are shifted in response to the external signals.

Discharge lamp lighting apparatus

Abstract: In a discharge lamp lighting apparatus of this invention, an AC voltage of a commercial AC power source (12) is full-wave-rectified by a rectifier (14), and this full-wave-rectified AC is smoothed by a smoothing circuit (16) connected to the output terminal of the rectifier (14). An inverter (38) is operated by a series resonance circuit constituted by a resonant choke coil (58) and a capacitor (60) and connected to the output terminal of the rectifier (14) and field-effect transistors (38, 40) connected to this series resonance circuit. By the operation of the inverter (36), a high-frequency AC is induced in an output winding (70) of a boosting transformer (66) having an input winding (68) connected in parallel with the capacitor (60) of the series resonance circuit, and discharge lamps (72₁, 72₂) are turned on.

Steady-state analysis and design optimization of an inductor-transformer resonant DC-DC converter

Abstract: The authors present a closed-form steady-state analysis of an inductor transformer resonant DC-DC power converter. This efficient method of analysis, which directly predicts the steady-state characteristics of the circuit, is used to develop an optimal design methodology. Normalized optimum design tables and curves are derived. The optimization procedure is summarized and is illustrated by a design example. State plane analysis is used to show the important role of the circuit leakage inductances on the steady-state performance of the system. Experimental results obtained from a prototype converter are used to verify the analytical results. >

Device and method for starting electric arc of a welder

Abstract: A method and apparatus for starting the electric arc of a welder by applying a high frequency, high voltage starting signal across the spark gap between the electrode and workpiece of the welder. This device and method comprises a series resonant circuit having a capacitive reactance element and an inductive reactance element combining to establish a resonant frequency for the series circuit, electrical drive means for energizing the series circuit at a driving frequency near a harmonic of the resonant frequency and means for converting the voltage developed across at least a portion of a designated one of the elements, generally the inductive reactance, into the starting signal.

Bi-mode high voltage resonant power supply and method

Abstract: A capacitor-charging series resonant mode, high voltage power supply (SRMPS) (10) includes a switching network (30) that alternately applies a positive and negative voltage to a series resonant circuit, comprising a resonant capacitor and inductor. The inductor may include the primary winding (14) of a power transformer (12). The switching action occurs at a fixed frequency above the audible range. This frequency is approximately the resonant frequency of the series resonant circuit. The switching action causes sine wave quantums of current of alternating phase to flow through the primary winding. Secondary windings (16) of the transformer are coupled through a suitable rectifying network (18) to charge a load capacitor CL to a high voltage. During a first mode of operation the load capacitor is charged at a maximum rate. During a second mode, the load capacitor is charged only as needed to maintain a desired charge thereon. Switching between the two modes occurs automatically depending upon the capacitive load requirements. The first mode operates with a control loop open, and is used when initially charging the load capacitor. The second mode operates with the control loop closed, at a low duty cycle, and allows only a small sliver of the front end of the sine wave current quantum to flow through the primary winding.

Fluorescent lamp light ballast system

Abstract: A 50 Hz or 60 Hz AC line voltage is rectified and converted to a DC voltage signal by a fluorescent lamp light ballast system. The DC voltage signal drives a pair of transistors to alternate between ON and OFF states, thereby producing a high frequency signal. A resonant circuit of the light ballast system converts the high frequency signal into a high amplitude, high frequency voltage signal needed to excite a fluorescent lamp load into operation. A protective circuit is employed to stop the generation of the high amplitude, high frequency voltage signal when the lamp load is in a burnout condition or when the lamp load is being replaced.

A PWM Current-Source Inverter for High Quality Drives

Abstract: SummaryWith fast microprocessors and suitable switching devices such as GTO thyristors CSI-drives are considerably improved. Sinusoidal input and output currents are replacing the block-shaped currents of sequentially commutated inverters and a sophisticated control permits fast dynamic response. To achieve this goal, the resonant circuit consisting of the capacitors at the invener terminals and the machine inductances has to be kept under close control. With an online calculation of the PWM switching times, not only the voltages but also the Currents are maintained very close to the reference value, even at limited switching frequency. Measurements at the machine-side converter show the distinctive features of this drive system at various operating points.

Local oscillation circuit for band switching

Abstract: To convert a received signal of different frequency bands (low and high for a VHF television set) to an intermediate frequency, the oscillation frequency of the local oscillation circuit must be changed for each band. The change to a desired frequency is made by shorting a part of a coil in a resonance circuit at high-band reception. However, a feedback capacitor constituting the oscillation circuit is fixed irrespective of the band. In this invention, the capacity between the collector and the emitter of an oscillation transistor (16) is decreased at high-band reception, while the capacity between the emitter and the base is increased. Conversely, at low-band reception, the capacity between the collector and the emitter is increased, while the capacity between the emitter and the base is decreased. Such switching of a capacity is achieved with one capacitor (21).

Method and circuit to operate a low-pressure discharge lamp, particularly compact fluorescent lamp

Abstract: To decrease the losses in the starting circuit for a compact fluorescent p, a positive temperature coefficient (PTC) resistor (KL) is connected in a resonance circuit of the lamp and also connected to the power supply of the lamp through a diode, polarized in blocking direction with respect to direct current, so that, before the lamp fires, a-c provided from an inverter (INV) can pre-heat the electrodes (E1, E2) of the lamp (LP), which will also cause current flow through the PTC resistor (KL); upon heating of the PTC resistor, this d-c current decreases and the voltage across the electrodes of the lamp will rise. When the lamp fires, it will drop below the supply voltage of the operating circuit for the lamp, thus causing the removal of the PTC resistor from the current carrying circuit, thereby eliminating energy loss through that resistor, and heating of the operating circuit assembly.

Temperature compensated electrical sensor system for measuring ferrous particles in a fluid using a series resonant oscillator and microprocessor

Abstract: A magnetic sensor for the collection and measurement of ferrous particles through the use of an electronic tuned circuit is disclosed. The sensor contains an electrical inductance coil along with an integral magnet to attract ferrous particles suspended in the fluid. The ferrous particles collecting on the magnetic surface of the sensor causes a change in the inductance of the integral coil which is measured by an electronic circuit. The electronic circuit operating in conjunction with the sensor utilizes a series resonant circuit. A measurement of the voltage across the series resonant circuit is responsive to changes in temperature of the inductance coil. A microprocessor is used to determine the change in period of the resonant oscillation with change in inductance of the coil. The microprocessor uses the data on temperature variation to correct the observed change in oscillator period for the effects of temperature. The sensor may be located in environmental conditions which include a large variation in ambient temperature. The microprocessor may be interrogated to obtain information on the total debris accumulated, the presence of any rapid or large debris accumulation and the variation of the temperature in the probe.