Showing papers on "RLC circuit published in 2004"

Fully integrated SiGe VCOs with powerful output buffer for 77-GHz automotive Radar systems and applications around 100 GHz

Abstract: It is demonstrated that SiGe bipolar technologies are well suited for voltage-controlled oscillators (VCOs) in 77-GHz automotive radar systems. For this, the design of a VCO with powerful output buffer (with good decoupling capability and high output power), comparatively wide tuning range, and reasonably low phase noise is described. To achieve the required high output power, the potential operating range of the output transistors, limited by high-current effects and avalanche breakdown, respectively, had to be exploited using adequate transistor models. The VCOs need a single supply voltage only and have been fully integrated (including resonant circuit and output buffer) on a single small (1 mm/sup 2/) chip, demonstrating their low-cost potential. Experimental results showed, at a center frequency of around 77 GHz, a usable tuning range of 6.7 GHz and a phase noise of -97 dBc/Hz at 1-MHz offset frequency averaged over this range. In addition, the center oscillation frequency can be coarsely adjusted within a wide range by cutting links in the upper metallization layer. The total signal power delivered by both buffer outputs together is as high as 18.5 dBm at a power consumption of 1.2 W. Simulations let us expect a potential doubling of the output power (for two or four outputs) by extension of the output buffer. To get an impression of the maximum frequency achievable with the circuit concept and technology used, a second VCO (again with buffered output) has been developed. To the best of the authors' knowledge, the measured maximum oscillation frequency of about 100 GHz, at 12.4-dBm total output power (14.3 dBm at 99 GHz), is a record value for SiGe VCOs with buffered output operating at their fundamental frequency. The usable tuning range is still 6.2 GHz.

Methods and apparatus for control of inductively coupled power transfer systems

Abstract: A power pick-up for an Inductively Coupled Power Transfer (ICPT) system is provided having a resonant pick up circuit. The natural frequency of the pick-up circuit may be varied by controlling the conductance or capacitance of a variable reactive in the resonant circuit. The load being supplied by the pick-up circuit is sensed, and the effective capacitance or inductance of the variable reactive component is controlled to vary the natural resonant frequency of the pick-up circuit to thereby control the power flow into the pick-up to satisfy the power required by the load.

Adaptive multi-mode resonant piezoelectric shunt damping

Abstract: Multiple-modes of structural vibration can be suppressed through the connection of an electrical impedance to the terminals of a bonded piezoelectric transducer. The so-called resonant shunts, one commonly used class of shunt impedances, provide good nominal damping performance but they are highly sensitive to variations in transducer capacitance and structural resonance frequencies. This paper introduces a new technique for the online adaptation of multi-mode resonant shunts. By minimizing the relative phase difference between a vibration reference signal and the shunt current, circuit component values can be optimally tuned online. Experiments on a cantilever beam validate the proposed technique and demonstrate the simplicity of implementation. The adaptive law converges quickly and maintains optimal performance in the presence of environmental uncertainties.

Resonant switched capacitor converter with high efficiency

Abstract: Conventional switched capacitor converters have an inherent drawback that their efficiency is much decreased as the output current is increased. This inherent drawback is due to a periodical forced charging and discharging operation in the internal switched capacitors accompanied by a large capacitor current, so that their efficiency can not be increased by decreasing its internal resistance. As a result, conventional switched capacitor converters have been limited to be used with a very small output current. This paper presents some novel switched capacitor converter topologies that use a resonant operation instead of the forced charging and discharging operation. Their advantage over conventional switched capacitor converters is a high efficiency even in a high output current region. The operation analysis and steady-state characteristics are described in detail for a half-buck type switched capacitor converter, and they are confirmed by experiments.

A CMOS impulse generator for UWB wireless communication systems

Abstract: A fully integrated CMOS impulse generator was designed as a part of the System-on-Chip (SOC) implementation of an Ultra-Wide-Bandwidth (UWB) wireless communication system. Three interpolation delay blocks in series and an XOR block are utilized for the pulse generation. The Gaussian Mono-pulse is generated with a RLC Band-Pass Filter (BPF), and a substrate RF inductor is utilized to avoid using off-chip components. The ideal BPF and the substrate BPF simulation results were compared to predict the actual performance of the impulse generator. The substrate BPF brings wider -3 dB bandwidth (BW), less ripple ratio, and smaller output amplitude. It operates with a center frequency of 3.27 GHz and a -3 dB BW of 3.34 GHz with an inductor value of 10 nH. The impulse generator was designed with MOS current mode logic (MCML) in the TSMC 0.18 /spl mu/m CMOS process.

A readout circuit for an intra-ocular pressure sensor

Abstract: A readout circuit for a passive telemetric intra-ocular pressure (IOP) sensor is being developed. The intra-ocular sensor consists of a capacitive pressure sensor in parallel with a planar coil. This inductor–capacitor (LC) resonant circuit transduces the pressure into a shift of resonance frequency. A voltage controlled oscillator (VCO) is used to excite the sensor over a large frequency range (20–40 MHz), hereby detecting resonance of the internal sensor, and thus enabling the measurement of the intra-ocular pressure. This low power circuit is extremely compact, making it suitable for long-term ambulant patient monitoring. The circuit allows wireless readout of the smallest pressure transducers. Tests show promising results at mutual coil distances up to 7.5 mm.

RLC window size reconfiguration

Abstract: A telecommunications device comprises a transceiver (33); a radio link control entity (50); and, a radio link control (RLC) buffer memory (150). The transceiver (33) which enables the device to communicate over an air interface (32). The radio link control entity (50) forms uplink RLC protocol data units (PDUs) for transmission over the air interface (32) and receives downlink RLC protocol data units (PDUs) over the air interface (32). The radio link control (RLC) buffer memory (150) is configured to include a transmitter buffer for storing the uplink RLC protocol data units (PDUs) and a receiver buffer for storing the downlink RLC protocol data units (PDUs). The radio link control entity includes RLC reconfiguration logic means (200) which reconfigures at least one of a size of a transmitter buffer window and a size of a receiver buffer window. In performing the reconfiguration, the RLC reconfiguration logic means implements a strategy for handling at least one of (1) downlink RLC protocol data units (PDUs) which are outside a new receiver buffer window; and (2) uplink RLC protocol data units (PDUs) which are either outside a new transmitter window or whose receipt by the radio access network has not been positively acknowledged.

Gas/liquid ratio measurements by rf resonance capacitance sensor

Abstract: A radio-frequency resonance sensor with variable capacitance for gas/liquid volume ratio measurements is presented The variable capacitor is made in the form of two semi-cylindrical electrodes, mounted on the outer side of the wall of a dielectric pipeline through which a liquid with gaseous bubbles flows The variation in the percentage of the gas and liquid causes the capacitance of the electrodes to be changed Because the electrodes are connected to a resonant circuit of an oscillator tuned to high frequency of 80 MHz, the capacitance variations change the frequency of this oscillator The changes of frequency generated by the oscillator are the measure of the gas and liquid volume ratio of a two-phase flow in the pipe In the experiments, two half-cylinder electrodes of height of 10 mm were mounted on the outside wall of a pipe of diameter of 40 mm The frequency deviations were up to 4 MHz when the pipe was empty or filled with water

Capacitance probe for thin dielectric film characterization

Abstract: A capacitance probe for thin dielectric film characterization provides a highly sensitive capacitance measurement method and reduces the contact area needed to obtain such a measurement. Preferably, the capacitance probe is connected to a measurement system by a transmission line and comprises a center conductive tip and RLC components between the center conductor and the ground of the transmission line. When the probe tip is in contact with a sample, an MIS or MIM structure is formed, with the RLC components and the capacitance of the MIS or MIM structure forming a resonant circuit. By sending a driving signal to the probe and measuring the reflected signal from the probe through the transmission line, the resonant characteristic of the resonant circuit can be obtained. The capacitance of the MIS or MIM structure is obtainable from the resonant characteristics and the dielectric film thickness or other dielectric properties are also extractable.

Discharge lamp lighting device and luminaire

Abstract: PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device having fewer parts and making highly precise frequency control. SOLUTION: In this discharge lamp lighting device lighting a discharge lamp La at high frequency with an inverter part 2 provided with a resonance circuit, an integrated circuit 4 for control in the inverter part 2 is provided with: a timer circuit 41 determining time to change to preheating, start up and lighting states by turns; first and second setting circuits 42, 43 setting an operating frequency of the inverter part 2 in the lighting state and the start-up state according to an output current value of a buffer means outputting a constant voltage; a drive circuit 47 inputting signals from the first and second setting circuits 42, 43 and generating driving signals for switching elements Q1, Q2 in the inverter part 2; and a switching circuit 44 switching an output current value of the buffer means in the first or the second setting circuit 42, 43 by switching a plurality of switching devices for control according to an output signal of the timer circuit 41 for setting the operating frequency of the inverter part 2 in the precedence preheating state. COPYRIGHT: (C)2006,JPO&NCIPI

Resonant circuit and a voltage-controlled oscillator

Abstract: A voltage-controlled oscillator comprising a resonant circuit and MOS transistors which constitute a negative resistance circuit of a differential structure. The resonant circuit consists of an inductance element and a MOS variable capacitance element connected in parallel therewith. The MOS variable capacitance element is divided into plural pairs connected in parallel with each other. A voltage division circuit generates staircase different-step DC bias voltages to be applied respectively to the gates of the plural divided MOS transistors. The divided MOS variable capacitance elements have a common terminal to which a common control voltage is applied. The resonant circuit is capable of reducing a load on the control voltage generator and improving the characteristics of the voltage-controlled oscillator.

Impedance, axial-ratio, and receive-power bandwidths of microstrip antennas

Abstract: Closed-form expressions for the impedance and axial-ratio bandwidths of a single-feed circularly polarized microstrip antenna have been derived. Receive-power bandwidths for both linearly and circularly polarized microstrip antennas have also been derived, which quantify the bandwidths when the microstrip antennas are used as receivers. The microstrip antennas are assumed to be probe fed and are modeled as RLC circuits (neglecting the probe inductances). For circular polarization, the probe feed is assumed to be along a 45/spl deg/ line across the microstrip antenna such that two orthogonal modes are identical in magnitude and in phase quadrature at the center frequency. Although derived for microstrip antennas, the expressions for impedance, axial-ratio, and receive-power bandwidth are also valid for other high-Q resonant antenna structures having an impedance behavior that is approximated by the same type of RLC circuits.

Antenna for reader writer for identification tag

Abstract: PROBLEM TO BE SOLVED: To vary the carrier frequency of a radio wave from a reader writer. SOLUTION: An exciting coil 11, a resonance circuit 12 which is electromagnetically coupled to the exciting coil 11, and an auxiliary electrode 13 to which a variable capacitor is connected are combined, and the auxiliary electrode 13 is capacitively coupled to the resonance circuit 12. COPYRIGHT: (C)2005,JPO&NCIPI

Exploiting Resonant Behavior to Reduce Inductive Noise

Abstract: Inductive noise in high-performance microprocessors is a reliabilityissue caused by variations in processor current (di/dt)which are converted to supply-voltage glitches by impedances inthe power-supply network. Inductive noise has been addressed byusing decoupling capacitors to maintain low impedance in thepower supply over a wide range of frequencies. However, evenwell-designed power supplies exhibit (a few) peaks of high impedanceat resonant frequencies caused by RLC resonant loops. Previousarchitectural proposals adjust current variations bycontrolling instruction fetch and issue, trading off performanceand energy for noise reduction. However, the proposals do notconsider some conceptual issues and have implementation challenges.The issues include requiring fast response, responding tovariations that do not threaten the noise margins, or respondingto variations only at the resonant frequency while the range ofhigh impedance extends to a resonance band around the resonantfrequency. While previous schemes reduce the magnitude of variations,our proposal, called resonance tuning, changes the frequencyof current variations away from the resonance band to anon-resonant frequency to be absorbed by the power supply.Because inductive noise is a resonance problem, resonance tuningreacts only to repeated variations in the resonance band, andnot to isolated variations. Reacting after a few repetitions allowsmore time for the response and reduces unnecessary responses,decreasing performance and energy loss.

A 5-GHz CMOS double-quadrature receiver front-end with single-stage quadrature generator

Abstract: A 5-GHz CMOS double-quadrature front-end receiver for wireless LAN application is proposed. In the receiver, a one-stage RLC phase shifter is used to generate quadrature RF signals. Implemented in 0.18 /spl mu/m CMOS technology, the receiver chip can achieve 50.6-dB image rejection with power dissipation of 22.4 mW at 1.8-V voltage supply.

MEMS-based reconfigurable antennas

Abstract: In this paper, two frequency reconfigurable antennas using the ON/OFF states of a microelectromechanical system (MEMS), are presented. A multifrequency planar inverted-F antenna (PIFA) is designed with a L-shaped open slot upon its main plate. As a proof-of-principle, an ON state RF MEMS switch, modeled by a piece of copper (1x1 mm/sup 2/), is inserted into the slot to achieve frequency switching (while OFF state is modeled without the piece of copper). According to the switch position alone the slot, the GSM operating frequency is not detuned while the other standards become reconfigurable. To validate our concept, a thermal MEMS switch, designed and developed at CEA-LETI is used. The MEMS switch is presented and its scattering parameters are measured and compared with simulated results from an equivalent RLC circuit. The active device is then inserted in the slot to valid the simulated frequency behaviour of the PIFA. Based on the same concept, a planar antenna is designed. It consists in a printed PIFA on a high-resistivity silicon substrate (10 k/spl Omega/.cm). The antenna resonates in the 2.4 GHz WLAN band but the insertion of two small gaps in its main aim which model the OFF state of a MEMS switch allows the antenna to work in the 5.150-5.875 GHz HIPERLAN 2 frequency bands.

Transmit-receive switching in wireless hearing aids

Abstract: Systems, devices and methods are provided to switch between transmit and receive modes in wireless hearing aids. One aspect relates to an apparatus for use within a communication system that has an inductive coil connected to a tuning capacitor at a node. An amplifier is connected to the node through a DC blocking capacitor to receive an induced signal in the inductive coil in a receive mode. A driver energizes the inductive coil with a driven signal in a transmit mode. According to various embodiments, the apparatus transforms the inductive coil, the tuning capacitor and the DC blocking capacitor into an equivalent series resonant circuit to reduce an inductive load in the transmit mode, and transforms the inductive coil, the tuning capacitor and the DC blocking capacitor into an equivalent parallel resonant circuit to increase an inductive load in the receive mode.

Impedance circuit, and filter circuit, amplifier circuit, semiconductor integrated circuit, electronic component, and wireless communications device using the same

Abstract: A filter circuit is provided wherein one end of an inductor is connected to one end of a capacitor to form a signal input end. The other end of the inductor is connected to a first switch circuit, and the other end of the capacitor is connected to a second switch circuit. When a lower-frequency signal in a 2.4 GHz band is to be inputted, a low-pass filter circuit is formed by connecting the other end of the inductor to a signal output end and the other end of the capacitor to ground, and when a higher-frequency signal in a 5 GHz band is to be inputted, a high-pass filter circuit is formed by connecting the other end of the inductor to ground and the other end of the capacitor to the signal output end, by manipulating the first and second switch circuits.

Method and apparatus for automatic tuning of a resonant loop antenna in a transceiver circuit

Abstract: Disclosed is a circuit and method for automatic tuning of a resonant circuit in a transceiver having a receiver and a transmitter that includes a power amplifier for driving the resonant circuit. During a transmit mode of the transceiver, a resonance voltage of the resonant circuit is compared to an input voltage signal to the power amplifier to determine an error signal that is converted into a control word. The control word drives an adjustable capacitance bank that is part of the resonant circuit. During a receive mode of the transceiver, the control word value is held constant to substantially maintain resonance of the resonant circuit during operation of the receiver.

Position pointing device

Abstract: A position pointing device includes a resonant circuit, a resonance-characteristic control circuit for controlling characteristics of the resonant circuit in accordance with pointing-device information at timing synchronized with at least part of an electromagnetic wave that is intermittently transmitted from a tablet and for returning the pointing-device information to the tablet, a clock oscillator circuit for generating a clock signal for driving the resonance-characteristic control circuit, and clock starting means for stopping an operation of the clock oscillator circuit when a start condition is set and for starting the operation of the clock oscillator circuit when the resonant circuit generates a signal specified by the start condition. The position pointing device further includes start-condition setting means for setting the start condition in the clock starting means at timing in accordance with an operation of the resonance-characteristic control circuit.

Method and apparatus for lighting a discharge lamp

Abstract: A reliable and efficient circuit for lighting a discharge lamp is described. An inverter accepts a direct current supply voltage and outputs an alternating current lamp voltage to drive the discharge lamp at a relatively high frequency. In one embodiment, the inverter includes semiconductor switches in a full-bridge configuration, a transformer feedback circuit to control the semiconductor switches, and a series L-C resonant circuit. In one embodiment, the inverter includes semiconductor switches in a half-bridge configuration, a transformer feedback circuit to control the semiconductor switches, and a series L-C resonant circuit. The inverter can drive multiple discharge lamps in a parallel configuration. A bypass circuit can also be coupled across a cathode of the discharge lamp to extend the life of the discharge lamp. The bypass circuit activates when a lamp cathode wears out.

Phase-shifted resonant converter having reduced output ripple

Abstract: A power converter (100) comprises a pair of resonant converter circuits 112-115, 132, 136, 138, 146 and 116-119, 134, 142, 144, 148) coupled together in parallel and operated at respective switching frequencies that are out of phase. The power converter includes a first resonant converter circuit and a second resonant converter circuit operatively coupled together. The first resonant converter circuit (112-115, 132, 146, 136, 138) includes at least one power switch (112, 114) adapted to convey power to a first resonant circuit (132, 146, 136, 138) and a first rectification (152, 154) stage adapted to rectify the conveyed power from the first resonant circuit. The second resonant converter circuit (116-119, 134, 148, 142, 144) includes at least one power switch (116, 118) adapted to convey power to a second resonant circuit (134, 148, 142, 144) and a second rectification stage (156, 158) adapted to rectify the conveyed power from the second resonant circuit. A filter capacitor (162) is coupled to the first and second rectification stages to provide DC output power therefrom. A regulator (126) is operatively coupled to the first and second resonant converters to control.

The Foster reactance theorem and quality factor for antennas

Abstract: The validity of the Foster reactance theorem for the general lossless or lossy antenna is considered for the straight-wire monopole and half-loop antennas. The finite diameter, lossy or lossless monopole, and half-loop behave as either a series RLC circuit near resonance or a parallel RLC circuit near antiresonance. For the Foster reactance theorem to be valid for the general antenna, the frequency derivative of the antenna's feed point reactance, X'(/spl omega/), must be positive for all values of frequency. This behavior is not consistent with that of a parallel RLC circuit near antiresonance and, therefore, the Foster reactance theorem is not valid for either the lossy or the lossless finite diameter antenna. Simulated and measured reactances of the finite diameter monopole and half-loop are shown to be in good agreement and are shown not to obey the Foster reactance theorem in frequency ranges near antiresonance. It is shown that the commonly used relationship between quality factor and |X'(/spl omega/)| is not valid in frequency ranges near antiresonance.

Semiconductor integrated circuit device

Abstract: PROBLEM TO BE SOLVED: To provide an oscillator capable of reducing oscillation power at the time of reaching the balanced state of oscillation without lowering small signal loop gain. SOLUTION: In the oscillator, on one main surface of a substrate composed of a semiconductor material, an FET 1, an output matching circuit C2 having a diode 2, an LC serial resonance circuit C1 having a capacitor 3 and an inductor 4, a transmission line 5 and a source inductor 6 are disposed. The source of the FET 1 is grounded through the source inductor 6. The drain of the FET 1 is connected through a transmission line 10 to the anode of the diode 2 constituting the output matching circuit C2. The FET 1 amplifies high frequency signals inputted to a gate and outputs them from the drain to the output matching circuit C2. The diode 2 limits the oscillation power. COPYRIGHT: (C)2004,JPO&NCIPI

Self-commutated auxiliary circuit ZVT PWM converters

Abstract: This paper introduces a novel class of zero voltage transition (ZVT) DC/DC pulse-width modulation (PWM) converters that use a resonant inductance-capacitance (L-C) circuit connected to the auxiliary switch, which is termed a self-commutated auxiliary circuit. It provides a simple and reliable means of achieving zero-current conditions (ZCS) for auxiliary switch commutations under wide line and load ranges, without the inclusion of any kind of DC voltage source. Furthermore, this auxiliary circuit is placed in parallel with the main power converter, retaining the ZVT characteristics. The self-commutated auxiliary circuit ZVT PWM boost is analyzed, and its feasibility and reliability are confirmed by experimental results obtained from laboratory prototypes rated at 1 kW and 100 kHz.

Noncontact IC card reader/writer

Abstract: The object of the invention is to provide a small-sized noncontact IC card reader/writer that can enhance the efficiency of an amplifier at a low cost. To achieve the object, in the invention, a loop antenna that supplies electric power and a send signal to a noncontact IC card by electromagnetic induction and acquires a receive signal from the noncontact IC card by load fluctuation, a first resonance circuit for resonating the loop antenna with a desired first frequency, a radio transmitter that supplies electric power and send data to the loop antenna via the first resonance circuit and further, a radio receiver that acquires the receive signal from the loop antenna via a second resonance circuit connected to the loop antenna via a coupling capacitor and resonated with a desired second frequency are provided, the radio transmitter and the radio receiver are respectively connected to CPU, and a low-pass filter for removing a high frequency, a class E amplifier and a modulator are connected to the radio transmitter in series.

Compact submicrosecond, high current generator for wire explosion experiments

Abstract: The PIAF generator was designed for low total energy and high energy density experiments with liners, X-pinch or fiber Z-pinch loads. These studies are of interest for such applications as surface and material science, microscopy of biological specimens, lithography of x-ray sensitive resists, and x-ray backlighting of pulsed-power plasmas. The generator is based on an RLC circuit that includes six NWL 180 nF–50 kV capacitors that store up to 1.3 kJ. The capacitors are connected in parallel to a single multispark switch designed to operate at atmospheric pressure. The switch allows reaching a time delay between the trigger pulse and the current pulse of less than 80 ns and has jitter of 6 ns. The total inductance without a load compartment was optimized to be as low as 16 nH, which leads to extremely low impedance of ∼0.12 Ω. A 40 kV initial voltage provides 250 kA maximum current in a 6 nH inductive load with a 180 ns current rise time. PIAF has dimensions of 660×660×490 mm and weight of less than 100 kg...

Resonance frequency shift canceling in wireless hearing aids

Abstract: Systems, devices and methods are provided to switch between transmit and receive modes in wireless hearing aids. Various aspects of the present subject matter relate to a communication system. Various embodiments of the communication system include an antenna with a resonant circuit having an inductive coil connected to a tuning capacitor. The communication system includes means to selectively drive the resonant circuit during a transmit mode, and means to selectively receive an induced signal in the resonant circuit during a receive mode. The communication system further includes means to selectively include a frequency shift canceling component in the resonant circuit to provide a first resonance frequency in the resonant circuit in the transmit mode and a second resonance frequency in the resonant circuit in the receive mode such that the first resonance frequency and the second resonance frequency are approximately equal. Other aspects are provided herein.

Magnetic stimulators and coils therefor

Abstract: A magnetic coil inductor for use in magnetic stimulators comprises two face-to-face electrically connected windings each having a multiplicity of turns of a respective conductor. Corresponding turns are separated by a gap which typically is of the order of 18 to 20% of the total height of the coil. The magnetic stimulator includes a discharge capacitor and a switch arrangement operable to provide discharge pulses at a selected repetition rate through the inductor, the inductor and the capacitor constituting a resonant circuit of which the resonant frequency is substantially in excess of the repetition rate and is typically between 2 and 6 kHz.