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Showing papers on "Inductor published in 1999"


Journal ArticleDOI
TL;DR: In this article, an analysis of phase noise in differential cross-coupled inductance-capacitance (LC) oscillators is presented, and the effect of tail current and tank power dissipation on the voltage amplitude is shown.
Abstract: An analysis of phase noise in differential cross-coupled inductance-capacitance (LC) oscillators is presented. The effect of tail current and tank power dissipation on the voltage amplitude is shown. Various noise sources in the complementary cross-coupled pair are identified, and their effect on phase noise is analyzed. The predictions are in good agreement with measurements over a large range of tail currents and supply voltages. A 1.8 GHz LC oscillator with a phase noise of -121 dBc/Hz at 600 kHz is demonstrated, dissipating 6 mW of power using on-chip spiral inductors.

972 citations


Patent
24 Sep 1999
TL;DR: In this article, a core of magnetic material is disposed for movement within a bobbin about which a coil of insulated, electrically conductive wire is wound, and at least one Hall effect device is disposed about the coil.
Abstract: A sensor for measuring linear displacement has a core of magnetic material disposed for movement within a bobbin about which a coil of insulated, electrically conductive wire is wound. At least one Hall effect device is disposed about the coil. The sensor is contained with a magnetic housing. When the coil is excited by a DC power source, the direction of magnetic flux flowing through the Hall effect device is dependent upon the position of the core.

539 citations


Proceedings ArticleDOI
03 Oct 1999
TL;DR: In this paper, the influence of nonsinusoidal flux-waveforms on the remagnetization losses in ferro- and ferrimagnetic materials of inductors, transformers and electrical machines used in power electronic applications is discussed.
Abstract: This paper discusses the influence of nonsinusoidal flux-waveforms on the remagnetization losses in ferro- and ferrimagnetic materials of inductors, transformers and electrical machines used in power electronic applications. The nonsinusoidal changes of flux originate from driving these devices by nonsinusoidal voltages and currents at different switching frequencies. A detailed examination of a dynamic hysteresis model shows that the physical origin of losses in magnetic material is the average remagnetization velocity rather than the remagnetization frequency. This principle leads to a modification of the most common calculation rule for magnetic core losses, i.e., to the "modified Steinmetz equation" (MSE). In the MSE the remagnetization frequency is replaced by an equivalent frequency which is calculated from the average remagnetization velocity. This approach allows, for the first time, to calculate the losses in the time domain for arbitrary waveforms of flux while using the available set of parameters of the classical Steinmetz equation, DC premagnetization of the material, having a substantial influence on the losses, can also be included. Extensive measurements verify the modified Steinmetz equation presented in this paper.

391 citations


Proceedings ArticleDOI
02 Jun 1999
TL;DR: In this paper, the authors proposed a semi-passive damping technique, where the piezoelectric device is simply continuously switched from open-circuit to shortcircuit synchronously to the mechanical strain.
Abstract: Passive damping using a piezoelectric device is a well-known technique. Both resistor and inductor loads connected to the piezoceramic are commonly used to attenuate a given resonance mode on a structure equipped with piezo dampers. The main drawback of this technique is its narrow band behavior and especially in the case of an inductor tuned passive piezo damper. The proposed technique is inherently wide band and does not rely on any tuned electric load. The piezoelectric device is simply continuously switched from open-circuit to short-circuit synchronously to the mechanical strain. It is called semi-passive because of the need of a sensor giving the strain of the piezo device. There is no need for external power supply unless for the low-level circuitry of the switch device. The damping efficiency appears to be twice what is obtained with pure resistive damping and is equivalent to what is achievable with a tuned inductor damper. It can work at any frequency without the need for large inductor especially for low frequency applications. A qualitative model gives an understanding of the damping mechanism.

321 citations


Book
01 Jan 1999
TL;DR: Takei et al. as mentioned in this paper presented a list of World's major Ferrite Suppliers and their application in magnetic material processing and applied them to a variety of applications such as DC and low frequency applications.
Abstract: Foreword Takeshi Takei. Preface. Acknowledgements. 1. Applications and Functions of Ferromagnetic Material. 2. Basics of Magnetism - Source of Magnetic Effect. 3. The Magnetization in Domains and Bulk Materials. 4. AC Properties of Magnetic Materials. 5. Materials for Permanent Magnet Applications. 6. DC and Low Frequency Applications. 7. Soft Cobalt-Iron Alloys. 8. Metallic Materials for Magnetic Shielding Applications. 9. High Permeability-High Frequency Metal Strip. 10. Metal Powder Cores for Telecommunications. 11. Crystal Structure of Ferrites. 12. Chemical Aspects of Ferrites. 13. Microstructural Aspects of Ferrites. 14. Ferrite Processing. 15. Ferrite Inductors and Transformers for Low Power. 16. Soft Magnetic Materials for EMI Suppression. 17. Ferrites for Entertainment Applications. 18. Ferrite Transformers and Inductors at High Power. 19. Materials for Magnetic Recording. 20. Ferrites for Microwave Applications. 21. Miscellaneous Magnetic Material Applications. 22. Physical-Thermal Aspects of Magnetic Materials. 23. Magnetic Measurements-Materials and Components. Bibliography. Appendix 1: Abbreviations and Symbols. Appendix 2: List of World's Major Ferrite Suppliers. Appendix 3: Units Conversion from CGS to MKS(SI) System. Index.

281 citations


Journal ArticleDOI
TL;DR: In this article, the authors presented a method for predicting parasitic capacitances of solenoid HF inductors made of one layer of turns with circular cross sections, uniformly wound around a cylindrical nonconductive core.
Abstract: This paper presents a method for predicting parasitic capacitances of solenoid HF inductors made of one layer of turns with circular cross sections, uniformly wound around a cylindrical nonconductive core. The method is based on an analytical approach to obtain the turn-to-turn and turn-to-shield capacitances of coils. The influence of the wire insulation is taken into account. An equivalent lumped parallel capacitance is derived. The method was tested by experimental measurements. The calculated and measured values were in good agreement in the considered cases. The derived expressions are useful for designing HF inductors and can also be adopted for modeling and simulation purposes.

236 citations


Journal ArticleDOI
TL;DR: A new family of AC-DC converters is derived which integrate the functions of low-harmonic rectification, low-frequency energy storage, and wide-bandwidth output voltage control into a single converter containing one, two, or four active switches.
Abstract: A new family of AC-DC converters is derived which integrate the functions of low-harmonic rectification, low-frequency energy storage, and wide-bandwidth output voltage control into a single converter containing one, two, or four active switches. These converters utilize a discontinuous conduction mode input inductor, an internal energy storage capacitor, and transformer secondary circuits which resemble the bridge, forward, flyback, or Cuk DC-DC converters. A large-signal equivalent circuit model for this family is presented, which uses the "loss-free resistor" concept. Design strategies and experimental results are given. High-performance regulation with satisfactory line-current harmonics is demonstrated with conventional duty-ratio control. Further improvements in line current are possible by simultaneous duty-ratio and switching-frequency control.

204 citations


Journal ArticleDOI
TL;DR: In this article, a new family of low-ripple DC-to-DC switching converters based on a parallel connection of N-identical boost converters with current-mode control (CMC) is presented.
Abstract: A new family of low-ripple DC-to-DC switching converters based on a parallel connection of N-identical boost converters with current-mode control (CMC) is presented. The CMC strategy ensures that all the converters operate at the same duty cycle, sharing an equal amount of input current and forcing the output voltage to be an integer multiple (N) of the input voltage. As a result, the total input current and output voltage ripples are extremely low. The generation of control signals from inductor currents feedback without using external triangular or sawtooth signals is another characteristic of the new converter family.

178 citations


Journal ArticleDOI
TL;DR: In this paper, a thin-film inductor for 1 GHz-drive mobile communication handset application has been demonstrated in a 370 μm×370 μm square four turn spiral of line/space with 0.1-μm-thick slitted Fe61Al13O26 film with Cr underlayer.
Abstract: Thin-film inductors for 1 GHz-drive mobile communication handset application has been demonstrated. This is the possible practical application of soft magnetic films in 1 GHz range. Fe61Al13O26 with Ms=1.2 T, ρ=500 μΩ cm, fr=2 GHz were used for the inductors. L=7.6 nH, R=6.5 Ω, and Q=7.4 were obtained at 1 GHz in a 370 μm×370 μm square four turn spiral of line/space=11 μm/11 μm covered with 0.1-μm-thick slitted Fe61Al13O26 film with Cr underlayer. The L was increased over the flux saturated inductor by 8.6% without any degrade of quality factor.

163 citations


Proceedings ArticleDOI
01 Jun 1999
TL;DR: This method uses the the physical dimensions of the inductor as the design parameters and handles a variety of specifications including fixed value of inductance, minimum self-resonant frequency, minimum quality factor, etc.
Abstract: We present an efficient method for optimal design and synthesis of CMOS inductors for use in RF circuits. This method uses the the physical dimensions of the inductor as the design parameters and handles a variety of specifications including fixed value of inductance, minimum self-resonant frequency, minimum quality factor, etc. Geometric constraints that can be handled include maximum and minimum values for every design parameter and a limit on total area. Our method is based on formulating the design problem as a special type of optimization problem called geometric programming, for which powerful efficient interior-point methods have recently been developed. This allows us to solve the inductor synthesis problem globally and extremely efficiently. Also, we can rapidly compute globally optimal trade-off curves between competing objectives such as quality factor and total inductor area. We have fabricated a number of inductors designed by the method, and found good agreement between the experimental data and the specifications predicted by our method.

154 citations


Patent
Cheng P. Wen1
19 Aug 1999
TL;DR: A coplanar waveguide structure for use in constructing a monolithic microwave integrated circuit high power amplifier was proposed in this paper, where the ground plane electrodes were separated from an adjacent ground plane electrode by a gap.
Abstract: A coplanar waveguide structure for use in constructing a monolithic microwave integrated circuit high power amplifier The coplanar waveguide structure is a coplanar transmission line segment having more than two ground plane electrodes and a plurality of signal/dc current carrying electrodes The current carrying electrodes are each separated from an adjacent ground plane electrode by a gap The coplanar waveguide structure forms a shunt inductor for the monolithic microwave integrated circuit high power amplifier The electrodes are shorted at one end to form the shunt inductor A center ground plane electrode is preferably at least twice the width of the signal carrying electrode The gaps between the signal carrying electrode and the ground electrodes are preferably at least one half the width of the signal carrying electrode to minimize current crowding

Proceedings ArticleDOI
03 Oct 1999
TL;DR: In this article, a single-phase PWM voltage-source rectifier with zero-ripple output current control is proposed, which requires neither a large DC capacitor nor a passive L-C resonant circuit.
Abstract: A novel topology of single-phase pulsewidth modulation (PWM) voltage-source rectifier capable of achieving not only a sinusoidal input current, but also a zero-ripple output current, is presented. The rectifier consists of a conventional single-phase PWM voltage-source rectifier, a pair of additional switches and an inductor. Hence, the proposed rectifier requires neither a large DC capacitor nor a passive L-C resonant circuit. The input current control is achieved by the conventional PWM current control technique. However, DC ripple current reduction control is difficult because one of the switching legs in the DC ripple current reduction circuit is shared with the PWM rectifier circuit. Two control methods, referred to here as the DC C inductor method and the AC inductor method, are proposed for DC ripple reduction, and the characteristics of these control methods are discussed. These control methods are implemented using a microprocessor, and the effectiveness of the circuit is confirmed experimentally. This rectifier has useful applications in uninterruptible power systems and DC power supplies, especially for cases in which the batteries are connected in parallel to the DC line.

Patent
18 May 1999
TL;DR: In this paper, the authors presented a reliable modular production quality excimer laser capable of producing 10 mJ laser pulses in the range of 1000 Hz to 2000 Hz or greater with the use of a high voltage power supply with a voltage bleed-down circuit.
Abstract: The present invention provides a reliable modular production quality excimer laser capable of producing 10 mJ laser pulses in the range of 1000 Hz to 2000 Hz or greater. Replaceable modules include a laser chamber (211); a pulse power system comprised of three modules; an optical resonator comprised of a line narrowing module (206) and an output coupler module (216); a wavemeter module (213), an electrical control module (205), a cooling water module (203) and a gas control module (202). Improvements in the pulse power unit to produce faster rise time and improved pulse energy control include: sn increased capacity high voltage power supply with a voltage bleed-down circuit for precise voltage trimming, an improved commutation module (209) that generates a high voltage pulse from the capacitors charged by the high voltage power supply (20) and amplifies the pulse voltage 23 times with a very fast voltage transformer having a secondary winding consisting of a single four-segment stainless steel rod. The compression head (207) saturable inductor greatly reduces the quantity of oil required and virtually eliminates the possibility of oil leakage.

Patent
17 Mar 1999
TL;DR: In this paper, a modular production quality excimer laser capable of producing 10 mJ laser pulses at 2000 Hz with a full width half, maximum bandwidth of about 0.6 pm or less.
Abstract: The present invention provides a reliable modular production quality excimer laser capable of producing 10 mJ laser pulses at 2000 Hz with a full width half, maximum bandwidth of about 0.6 pm or less. Replaceable modules include a laser chamber; a pulse power system comprised of three modules; an optical resonator comprised of a line narrowing module and an output coupler module; a wavemeter module, an electrical control module, a cooling water module and a gas control module. Improvements in the laser chamber permitting the higher pulse rates and improved bandwidth performance include a single upstream preionizer tube and a high efficiency chamber. The chamber is designed for operation at lower fluorine concentration. Important improvements have been provided in the pulse power unit to produce faster rise time and improved pulse energy control. These improvements include an increased capacity high voltage power supply with a voltage bleed-down circuit for precise voltage trimming, an improved commutation module that generates a high voltage pulse from the capacitors charged by the high voltage power supply and amplifies the pulse voltage 23 times with a very fast voltage transformer having a secondary winding consisting of a single four-segment stainless steel rod. A novel design for the compression head saturable inductor greatly reduces the quantity of transformer oil required and virtually eliminates the possibility of oil leakage which in the past has posed a hazard.

Journal ArticleDOI
TL;DR: In this paper, the authors derived general topological and electrical properties common to all lossless passive soft-switching power converters with defined characteristics, and proposed a synthesis procedure for the creation of new power converter.
Abstract: This paper derives general topological and electrical properties common to all lossless passive soft-switching power converters with defined characteristics, and proposes a synthesis procedure for the creation of new power converters. The synthesis procedure uses the properties to determine all possible locations for the resonant inductors and capacitors added to achieve soft switching. A set of circuit cells is then used to recover the energy stored in these resonant elements. This paper also explains the operation of the circuit cells and the many new passive lossless soft-switching power converters. A family of soft-switching boost converters is given as an example of the synthesis procedure. Experimental waveforms are also shown for a new soft-switching Cuk converter.

Journal ArticleDOI
TL;DR: In this article, a new strategy for controlling voltage and frequency of a self-excited induction generator (SEIG) is presented, which operates in the linear region of the core magnetizing curve, so that efficiency and performance are upgraded.
Abstract: A new strategy for controlling voltage and frequency of a self excited induction generator (SEIG) is presented. The SEIG operates in the linear region of the core magnetizing curve, so that efficiency and performance are upgraded. An external excitation circuit, comprising permanently connected capacitors and electronically switched inductances is used. The external circuit allows to compensate for the generator reactive demand. A detailed analysis is performed, showing some salient aspects related to the connection of the external excitation circuit on the control performance. Asynchronous switching is used, but some important considerations must be taken into account related to the instantaneous phase angle between stator voltage and external inductor current at the switching instant, if good transient response is desired. Sliding mode controllers are proposed, showing good dynamic response and robust behavior upon changes in load and generator parameters. Computer simulations are used to demonstrate the validity of the proposed scheme.

Proceedings ArticleDOI
J.H. Alimeling1, W.P. Hammer1
27 Jul 1999
TL;DR: In this article, a toolbox, called PLECS, for the fast simulation of power electronic circuits under Simulink is presented, based on a state-space formulation for circuits that consist of linear elements (RLC), transformers, sources, meters and ideal switches.
Abstract: In this paper a new toolbox, PLECS, for the fast simulation of power electronic circuits under Simulink is presented. This toolbox provides the means for modeling large power electronic systems containing both electrical circuits and controllers. The program is based on a state-space formulation for circuits that consist of linear elements (RLC), transformers, sources, meters and ideal switches. Diodes, thyristors, IGBTs and other nonlinear elements such as saturable inductors can be assembled by combining linear elements and switches. Thus, a piece-wise linear model is attained which leads to a stable and fast simulation. An attached benchmark simulation demonstrates the capability of PLECS.

Patent
23 Mar 1999
TL;DR: In this paper, a high quality factor (Q) spiral and toroidal inductor and transformer are disclosed that are compatible with silicon very large scale integration (VLSI) processing, consume a small IC area, and operate at high frequencies.
Abstract: High quality factor (Q) spiral and toroidal inductor and transformer are disclosed that are compatible with silicon very large scale integration (VLSI) processing, consume a small IC area, and operate at high frequencies. The spiral inductor has a spiral metal coil deposited in a trench formed in a dielectric layer over a substrate. The metal coil is enclosed in ferromagnetic liner and cap layers, and is connected to an underpass contact through a metal filled via in the dielectric layer. The spiral inductor also includes ferromagnetic cores lines surrounded by the metal spiral coil. A spiral transformer is formed by vertically stacking two spiral inductors, or placing them side-by-side over a ferromagnetic bridge formed below the metal coils and cores lines. The toroidal inductor includes a toroidal metal coil with a core having ferromagnetic strips. The toroidal metal coil is segmented into two coils each having a pair of ports to form a toroidal transformer.

Patent
09 Sep 1999
TL;DR: In this article, a split coil is used to define parallel electrical paths in a magnetoresistive head with multiple similar coil layers separated by an insulator and joined at their ends.
Abstract: A magnetoresistive head having a split coil structure including multiple, similar coil layers separated by an insulator and joined at their ends to define parallel electrical paths. The coil passes through a magnetic yoke having an open end and a closed end and is electrically insulated from the yoke. The parallel electrical paths of the separate coil layers can each be modeled as a resistor in series with an inductor, each of the paths also being in parallel with a capacitor. The split coil has a much faster current rise time than a comparable single layer coil or than multiple coils connected in series. Since the coil current provides the magneto-motive force for imparting a signal on a passing recording medium, the decreased current rise time corresponds to an increased data recording rate.

Journal ArticleDOI
01 May 1999
TL;DR: In this paper, the authors considered the problem of providing four regulated DC sources for use in a diode clamped five-level inverter and proposed a new technique whereby the voltage across each of these capacitors is maintained constant using a switching circuit.
Abstract: The paper considers the problem of providing four regulated DC sources for use in a diode clamped five-level inverter. The preferred approach is to provide a single DC link supply and subdivide this into five levels using four series connected capacitor banks which have equally balanced voltages. The paper first considers the use of modified output switching strategies to redistribute energy through the DC link capacitors and maintain correct voltage balance, but concludes that this technique is restricted to outputs with a low modulation. The paper then presents a new technique whereby the voltage across each of these capacitors is maintained constant using a switching circuit: the balancer circuit. The design and control of the balancer circuit is described and its operation is validated on an 11 kW prototype vector controlled induction motor drive. Full four-quadrant operation is demonstrated. This arrangement eliminates the need for complex isolated supply arrangements typically found in multilevel drives. The balancer circuit takes the form of a fourth output leg with the addition of two inductors. This circuit is certainly viable for medium voltage drive applications.

Journal ArticleDOI
Jun-Bo Yoon1, Bonkee Kim1, Chul-Hi Han1, Euisik Yoon1, Choong-Ki Kim1 
TL;DR: In this paper, the performance of surface micromachined solenoid on-chip inductors fabricated on a standard silicon substrate (10 /spl Omega/spl middot/cm) has been investigated and the results are compared with the same inductors on glass.
Abstract: RF performance of surface micromachined solenoid on-chip inductors fabricated on a standard silicon substrate (10 /spl Omega//spl middot/cm) has been investigated and the results are compared with the same inductors on glass. The solenoid inductor on Si with a 15-/spl mu/m thick insulating layer achieves peak quality (Q-) factor of 16.7 at 2.4 GHz with inductance of 2.67 nH. This peak Q-factor is about two-thirds of that of the same inductor fabricated on glass. The highest performance has been obtained from the narrowest-pitched on-glass inductor, which shows inductance of 2.3 nH, peak Q-factor of 25.1 at 8.4 GHz, and spatial inductance density of 30 nH/mm/sup 2/. Both on-Si and on-glass inductors have been modeled by lumped circuits, and the geometrical dependence of the inductance and Q-factor have been investigated as well.


Patent
14 Oct 1999
TL;DR: In this paper, the authors proposed a series-connected RFID tag circuit, which is made up of a first inductor and a second inductor connected in series, a first capacitor, a second capacitor, and a switch.
Abstract: An RFID tag circuit provides magnetic decoupling and amplitude modulation. The circuit is made up of a first inductor and a second inductor connected in series, a first capacitor, a second capacitor, and a switch. The circuit includes a first resonant circuit formed from a parallel connection of the series connected first and second inductors, and the first capacitor. The first resonant circuit has a primary resonant frequency. The circuit also includes a second circuit formed from a series connection of the second capacitor and the switch. The series connection of the second capacitor and the switch are connected in parallel to the second inductor. One end of the series connected second capacitor and switch is connected to the common connection between the series connected first and second inductors.

Journal ArticleDOI
TL;DR: In this paper, a circuit model of ferrite core inductors is presented, where the behavior of the model parameters versus frequency is considered and the total power loss in inductors consisting of the winding resistance loss and the core loss, is modeled by a frequency-dependent equivalent series resistance.
Abstract: A circuit model of ferrite core inductors is presented. The behavior of the model parameters versus frequency is considered. The total power loss in inductors consisting of the winding resistance loss and the core loss, is modeled by a frequency-dependent equivalent series resistance. The total inductance given by the sum of the main inductance and the leakage inductance is obtained as a function of frequency. In order to study the core equivalent resistance and main inductance versus frequency, the magnetic field distribution in the core is derived from Maxwell's equations for a long solenoid. The complex permeability and permittivity of the ferrite core are introduced in the electromagnetic field equations. Experimental results are also given.

Journal ArticleDOI
TL;DR: In this article, the displacement angle between one of the resonant circuit variables, typically the current through resonant inductor, and the voltage at the output of the inverter, is controlled to ensure zerovoltage switching.
Abstract: This paper presents a new control technique for resonant converters. Unlike conventional variable frequency control which externally imposes the switching frequency, the proposed scheme is based on controlling the displacement angle between one of the resonant circuit variables, typically the current through the resonant inductor, and the voltage at the output of the inverter. As a result, zero-voltage switching (ZVS) can be ensured over a wide operating range. The proposed control technique cam be applied for series, parallel, and series-parallel resonant converters. As an example, the static characteristics and dynamic model of a series-parallel resonant converter with the proposed controller are derived and the system behaviour is investigated in detail. Experimental results are given to demonstrate the operation of resonant converters with the proposed controller and to validate the analysis.

Proceedings ArticleDOI
01 Jul 1999
TL;DR: In this article, an integrated planar inductor scheme for multi-module interleaved QSW power converters is proposed, which utilizes the phase relationships of the currents in each module to integrate all the separate inductors for each module into one core, resulting in great reductions in the size and power losses of the inductor.
Abstract: Compact, high-efficiency, low-voltage and large-current DC/DC power converters with a fast transient slew rate are needed for future generation microprocessors. The interleaved quasi-square-wave (QSW) topology is a good candidate to improve their transient response significantly. Inductors are critical components in these converters. An integrated planar inductor scheme for multi-module interleaved QSW power converters is proposed. This integrated inductor utilizes the phase relationships of the currents in each module to integrate all the separate inductors for each module into one core, resulting in great reductions in the size and power losses of the inductor.

Proceedings ArticleDOI
Ting-Ping Liu1
15 Feb 1999
TL;DR: In this article, the authors proposed a VCO architecture incorporating two coupled fixed-frequency sinusoidal oscillators to generate a variable-frequency output by varying the coupling between two oscillators.
Abstract: Phase noise and frequency tuning range are key performance parameters of high-frequency voltage-controlled oscillators (VCOs). To achieve low phase noise, LC sinusoidal oscillators with high quality factor (Q) are preferred to other topologies, such as inverter-based ring oscillators. The frequency tuning of LC oscillators can be readily achieved with varactor diodes either on-chip or external. The frequency tuning range is often limited by low supply voltage and maximum variable capacitance available to varactors at high frequencies when on-chip inductors are used. Other frequency tuning approaches include varying current in the resonator to alter effective capacitance, or varying relative weighting between two different LC resonators. While the former approach varies loop gain in addition to the phase, the latter requires careful choice of the resonators and their Qs for stable oscillations. This VCO architecture incorporates two coupled fixed-frequency LC oscillators to generate a variable-frequency output by varying the coupling between two oscillators.

Patent
04 Mar 1999
TL;DR: In this article, a pulse frequency modulation drive circuit (1114) for a piezoelectric transformer (1102) with a resonant frequency and an output level sense (1112) is presented.
Abstract: A pulse frequency modulation drive circuit (1114) for a piezoelectric transformer (1102) is provided. Circuit (1114) includes a piezoelectric transformer (1102) having a resonant frequency and an input and an output section. A frequency feedback network connected to the piezoelectric transformer (1102) and an output level sense (1112) connected to the piezoelectric transformer (1102) is also provided. A drive circuit (1114) has a first switch (S1) and a third switch (S3) having a capacitance (1118) therebetween. A second switch (S2) and a fourth switch (S4) connect a supply voltage (VIN) to each of a pair of inductors (L1 and L2) and the second switch (S2) and the fourth switch (S4) are driven 180° out of phase at the resonant frequency of the piezoelectric transformer (1102).

Patent
Patrice R. Lethellier1
28 Jun 1999
TL;DR: In this paper, a buck-type circuit topology with a multiple winding inductor is proposed for converting relatively high input voltages to relatively low output voltages, where an optional winding is provided to the inductor to clamp a voltage spike appearing on the drain of one of the switching devices.
Abstract: A DC--DC power converter circuit for converting relatively high input voltages to relatively low output voltages employs a buck-type circuit topology with a multiple winding inductor. An optional winding is provided to the inductor to clamp a voltage spike appearing on the drain of one of the switching devices. Optionally, two inductor windings may be capacitively coupled for better efficiency.

Journal ArticleDOI
TL;DR: A new cell which lends itself as a generic current multilevel one is applied to current-source inverters with output current harmonics minimization and without the use of high-frequency modulation.
Abstract: In this paper, a new cell which lends itself as a generic current multilevel one is applied to current-source inverters with output current harmonics minimization and without the use of high-frequency modulation. In this cell, inductors acting as current sources ensure equal current division among switches. DC current balance in the inductors is achieved, also, without closed-loop control. It is also shown that, while, for the five-level structure it is easy to find a proper control strategy, for higher levels, it is necessary to use numerical simulation programs to find out a proper switching strategy. Simulation and experimental results are included to show the performance of the new cell for high-power applications.