Showing papers on "Inductor published in 1984"

Switching electrical power supply utilizing miniature inductors integrally in a PCB

Abstract: Electrical switching power supply for microprocessors and the like comprising a high voltage d.c. source (30, 34, 32, 50) resonant circuit (38, 51, 42, 52) including a switching transistor (52) which is operated in Megahertz range and provides pulses, via a transformer (40), rectifier (56), smoothing choke (62) to a d.c. low voltage output terminal (66). The rate of switching is controlled by a pulse generator (54) which pulses variably in response to output voltage to thereby vary switching repetition rate and hold to a predetermined output voltage. The inductive elements use spirals (12A and 12A') of thin lines on the surface of a substrate board and ferrite plugs (20) passing through holes (22) in the board to provide miniature inductive elements built into the substrate for effective use in a microprocessor power supply, or the like, and in other applications. Power dissipating elements on the circuit are mounted to a common thermal ground (29) and the circuit as a whole, including such thermal ground is encapsulated to provide a plate form power supply.

Planar inductor

Abstract: As the first step for developing magnetic I.C, planar inductors have been investigated. Planar inductor, which does not require conventional winding, consists of planar coil and two magnetic films which sandwich the coil. Design parameters have been obtained for four types of planar inductors, hoop type, spiral type, meander type and closed type. We fabricated a hoop type and a meander type planar inductor. The inductance of the hoop type was about 40 nH at 1 MHz, and showed flatness up to 10 MHz. In the meander type, the inductance was about 100 nH at 1 MHz, and showed a flat response till 40 MHz.

Regulated dc to dc converter

Abstract: A DC-DC converter includes first and second switches to be opened and closed at mutually exclusive times at a predetermined frequency. The first switch is connected to an inductor and a transformer primary winding so that a first current component from a DC input supply flows through it via the inductor. A second current component having a sinusoid component flows through the first switch in response to discharge of energy stored in a resonant circuit coupled to the transformer. The second component begins approximately simultaneously with closure of the first switch. The second switch, when closed, is connected so that a bidirectional current component flows through it in response to energy stored in the inductor. The rectifier is connected between the secondary winding and the load so the secondary winding supplies substantial current to the load.

Chip-type inductor

Abstract: A present invention is a chip-type inductor comprising a laminated structure (28) of a plurality of magnetic layers (1 to 8) in which linear conductive patterns (9 to 21) extending between the respective magnetic layers are connected successively in a form similar to a coil so as to produce an inductance component. The conductive patterns (12, 14, 16, 18, 20, 11 and 10) formed on the upper surfaces of the magnetic layers and the conductive patterns (9, 13, 15, 17, 19 and 21) formed on the lower surfaces of the magnetic layers are connected with each other in the interfaces of the magnetic layers and are also connected each other via through-holes (22 to 27) formed in the magnetic layers, so that the conductive patterns are continuously connected in a form similar to a coil.

Hybrid ac line transient suppressor

Abstract: An AC line transient suppressor includes a first metal oxide varistor connected between the "hot" and "neutral" lines of an AC power system. A first inductor is connected from the hot line to one terminal of a second metal oxide varistor, the other terminal of which is connected to the neutral line. A second inductor having approximately twice the value of the first one is connected from the junction between the first inductor and the second metal oxide varistor to a hot supply terminal to which equipment to be protected is connected. A silicon suppressor having a predetermined clamping voltage is coupled between the hot supply terminal and the neutral line conductor. The inductance of the first inductor has a value selected to divert approximately 95% of the transient surge current through the first metal oxide varistor. The second inductor diverts approximately 65% of the remaining surge current through the second metal oxide varistor, so that only approximately 2% of the total surge current flows through the silicon junction diode suppressor, allowing it to provide a low clamping voltage.

Implant communication system with patient coil

Abstract: A system is provided for communicating with a tank circuit that is implanted in a patient. The system comprises a telemetry circuit including an oscillator enclosed within a housing. An inductor coil is located outside of the housing for positioning externally on the patient in proximity to the implanted tank circuit. The inductor coil is connected to the telemetry circuit by electrical wiring, with the inductor coil being operative to form at least a portion of a resonant tank for the oscillator.

Electroluminescent display drive system

Abstract: A resonant mode energy recovery circuit is disclosed for supplying drive pulses to an electroluminescent (EL) display arranged as a matrix of pixels addressed by a plurality of column and row electrodes. An external inductor is used to alternately store and supply energy from the column electrodes of the EL display which has an impedance equivalent to an array of capacitors and resistors. Switching transistors and diodes are used to start and stop the resonant current flow at 1/4 wavelength intervals of the resonant frequency of the resonant tank formed by the external inductor and the array capacitors coupled to the column electrodes in order to form the pulses required to address the columns of the matrix. Switched current sources are used to start and stop nonresonant current flow to form the refresh and write pulses used to form the pulses required to address the rows of the matrix. Together, the pulses applied to the columns and rows of the matrix provide the high voltage necessary to light the EL pixels while minimizing the address time and power required to operate the EL display.

Electronic sensor for static magnetic field

Abstract: A magnetic field sensor including a resonant circuit having a coil. The resonant frequency varies with the strength of the magnetic field which passes through the coil. The resonant circuit is energized for approximately one-half cycle of the resonant frequency which characterizes the circuit in the absence of a magnetic field. During a sensing window of predetermined duration which then immediately follows, the voltage across the coil is examined for a zero crossing. A zero crossing will occur only in the presence of a magnetic field whose amplitude exceeds a threshold value.

Determination of AC magnetic power loss of electrical steel sheet: Present status and trends

Abstract: A brief survey of the status of work in the higher induction and frequency ranges is given and recent papers on the measurement of rotational losses are reviewed. The determination of the magnetic losses in alternating fields is considered, in partucular regarding the performance of those magnetic circuits most widely used in loss measurements. New and revised data contribute to the elucidation of the systematic errors of the Epstein square. The Epstein samples and plate samples, both of various materials, were used for measurements with single sheet testers, whereby the field strength was determined both from the magnetizing current by means of a precision resistor and direct, using field sensing coils. From these results conclusions for the appropriate value of the effective magnetic path length can be drawn. The electric power measurement particularly as regards digital procedures, calibration and uncertainties is briefly discussed.

Parallel-resonant bridge-inverter fluorescent lamp ballast

Abstract: Center-tapped DC power to a self-oscillating full-bridge inverter-type fluorescent lamp ballast is obtained from a regular power line by way of a voltage doubler. The DC power is supplied to the inverter through an inductor means having two separate windings on a common magnetic core--with one winding being positioned in each leg of the DC power supply. The full-bridge inverter, which comprises four switching transistors connected in usual full-bridge fashion, comprises a center-tapped parallel-tuned L-C circuit connected across its AC output, thereby providing a center-tapped sinusoidal voltage to its load, which consists of a fluorescent lamp connected in series with a current-limiting capacitor. Due to the effect of the inductor means, the current provided to the bridge is substantially constant during a complete period of the inverter's oscillation. The arrangement is symmetrical and provides for the center-tap of the DC voltage source to be at the same potential as the center-tap of the inverter's AC output; which means that the center-tap of this inverter or ballast output may be grounded without the need for using an isolation transformer.

Planar, lumped element, matched N-way power divider

Abstract: An N-way, lumped element, matched, isolated branch power divider in planar form is disclosed. Lumped inductors are disposed on the top surface of a dielectric substrate, an isolation resistor network is disposed on the bottom surface of the substrate and the substrate is suspended above a ground conductor by lumped element capacitors. The capacitance values of the capacitors and the inductance values of the inductors are selected to provide between the common terminal and each branch terminal a lumped element π network transmission line having a phase shift of about 90° at frequencies within an operating range of frequencies.

Semi-conductor motor control system

Abstract: A semi-conductor system for controlling three phase motors by voltage and/or frequency variations. An input circuit provides dc power, such as a three phase full wave input bridge with silicon control rectifiers to provide a voltage controlled dc power output. An output inverter bridge having six silicon rectifiers receives dc power and converts it to three phase ac power for operating an induction motor. A diverter network is connected between the dc power input circuit and the output inverter and is activated periodically for temporarily diverting the dc power from the inverter in order that the inverter rectifiers may be turned off. The diverter may include a tank circuit having a capacitor and an inductor connected across the dc power output through a diode and a silicon control rectifier is connected to the tank circuit for shunting the dc power from the inverter and applying a reverse voltage to the inverter. A harmonic suppression circuit is connected across the output of the converter and may include a capacitor connected between each of the three phase output lines of the inverter.

Integrated oscillator antenna for low power, low harmonic radiation

Abstract: A low-power transmitter for garage door operator systems and the like wherein harmonics of the fundamental frequency are suppressed by class A or AB oscillator operation and fundamental radiation is enhanced by way of a combined inductor/radiator having conductive printed circuit extrusions on the ends thereof to effectively form a center-fed dipole antenna.

Integrated laser head and low inductance pulse forming circuit for pulsed gas lasers

Abstract: Integrated laser head apparatus is disclosed for producing high energy pulses in pulsed gas lasers. The present invention provides high energy pulses over short time durations suitable for laser rangefinder systems due to an improvement in the arrangement of energy storage capacitors (22, 24) which keeps circuit inductance to a minimum. The pair of nested, ceramic capacitors (22, 24) are substantially cylindrical and are coupled through thin conductive layers (23). The capacitors are charged by a spark gap trigger (14), an inductor (18), and a charging resistor (52). The capacitors (22, 24) enclose a pressure vessel (28) which further encloses a laser resonator (12) including a laser output coupler mirror (42), totally reflective mirror (44), discharge electrodes (32, 34) and a central chamber (30) which contains a pressurized gaseous phase laser medium. The high voltage discharge electrode (32) is disposed coaxially with the surrounding capacitors (22, 24).

Ripple reduction circuit for an inverter

Abstract: A ripple reduction circuit for an inverter (16) which converts DC power supplied on DC buses (20, 22) into AC power to drive a load (10) includes a sensing transformer (32, 34) having a primary winding (32a, 34a) coupled to one of the buses by a switch (Q3, Q4) so that the ripple on the DC bus is sensed. A periodic voltage is impressed across a secondary winding (32b, 34b) of the sensing transformer due to the sensed rippled and this periodic waveform is coupled to a secondary winding (24b, 24c) of an output inductor. A primary winding (24a) of the output inductor is connected between the output of the inverter (16) and the load (10). The primary winding (24a) of the output inductor receives a first ripple component due to ripple on the DC bus and a second ripple component which opposes the first as a result of the periodic waveform in the secondary winding of the output inductor. The two ripple components substantially cancel one another and hence a low distortion power waveform is delivered to the load.

MOS FET amplifier output stage

Abstract: An output circuit particularly adapted for use in a pulse width modulation amplifier having a significantly reduced power loss during switching times. Inductors are coupled in series with the signal channels of two push-pull connected switching elements. High-speed diodes are coupled in parallel with the series combinations of switching elements and inductors.

Remote controlled television receiver power supply

Abstract: A mains rectified DC input voltage is applied to a series-pass regulator to develop a regulated B+ supply voltage. To reduce dissipation in the series-pass transistor, a shunt resistor parallels the series-pass transistor. To place the remote controlled television receiver in the standby-mode of operation, a remote standby control circuit applies an on/off command signal to the horizontal deflection circuit. Operation of the horizontal deflection circuit during the off-state of the command signal is disabled, thereby disabling the flyback transformer derived voltage supplies. A thyristor is placed in series with the shunt resistor and blocks current flow to the B+ supply terminal from the input voltage terminal during standby. To resume run-mode operation, the remote standby control circuit generates the on-state of the command signal to reenable horizontal deflection circuit. Current flowing to the B+ supply terminal from the regulator series-pass transistor also flows in an inductor to induce a voltage that is coupled to the gate of the thyristor to turn on the thyristor and reconnect the shunt resistor in parallel with the series-pass transistor.

Power bridge having a non-dissipative snubber circuit

Abstract: A non-dissipative snubber circuit for use in a power bridge circuit having a pair of switching power transistors for controllably coupling pulses of electrical current in opposite directions through the primary winding of a power transformer, to generate a 60 hertz ac power signal. The snubber circuit includes a separate snubber capacitor shunting each transistor, with the current flowing through the transformer's primary winding being diverted to charge one of the snubber capacitors each time the associated transistor is switched off. When the transistor is again switched on, the capacitor is reinitialized by discharging it through an inductor. In a half-bridge configuration, the discharge current is directed to a fixed reference node at the opposite side of the transformer's primary winding, whereas in a full-bridge configuration, the discharge current is used to discharge a separate snubber capacitor shunting one of two additional switching power transistors connected to the opposite side of the primary winding.

Computer Models for MMIC Capacitors and Inductors

Abstract: Computer models for MMIC interdigitated capacitors and rectangular spiral inductors are described. The theory of the interdigitated capacitor considers the influence of the metallization thickness, the end effects of the fingers, the exact position of the fingers on the main line and of the T-junctions in the capacitor. The theory of the rectangular spiral inductor is based on a line theory and considers the influence of the metallization thickness and the rectangular line bends.

Starting and operating method and apparatus for discharge lamps

Abstract: Starting and operating method and apparatus for discharge lamps comprises a current-limiting and rectifying means which provides at its output a low-ripple current-limited direct current. To effect lamp starting, a series-connected inductor and capacitor form a high "Q" resonant circuit with the capacitor connected across the lamp to be operated. This starting circuit connects through a blocking capacitor and charging resistor across the low-ripple source of DC. A pair of transistors which comprise an oscillator are connected emitter-to-collector across the source of DC, with the common-connected emitter and collector connected to the blocking capacitor. A drive air-core transformer has separate feedback windings in the starting and operating circuits and drive windings are associated with the transistors. A trigger diode is used to initially pulse one of the transistors which initially oscillate to generate square waves having a frequency corresponding to the resonant frequency of the starting circuit. After the lamp strikes, the transistors operate in a self-oscillating mode with the operating frequency determined by the rate of current flow into the operating feedback winding.

Steady-state characteristics of the capacitively loaded flux gate sensor

Abstract: An analytical derivation of the transient response of the capacitively loaded flux gate sensor has been presented in a previous paper [1]. Here the analysis is extended to include steady-state periodic solutions. The characteristic differential equation for the flux gate presented in [1] is used as a starting point. An equivalent circuit corresponding exactly to this equation is presented, avoiding the pitfalls associated with many saturable-core descriptions. This equivalence provides a means of obtaining an intuitive understanding of the flux gate which is quite different from conventional representations. The flux gate can be represented exactly as a current transducer in the form of a time-varying inductor L(t) loading a current source proportional to an ambient magnetic field H. We have extended the theory of Floquet, as presented by Nayfeh and Mook [2], to provide complete steady-state solutions to complement the transient solutions presented in [1] and can thus predict flux gate absolute sensitivity, parametric gain, and bandwidth. Further our description is based upon easily measured or observed properties, namely, sense-winding inductances with or without a permeable core, and real or equivalent circulating currents. Typical maps showing absolute sensitivity, parametric gain and dominating eigenvalues are also presented. The results agree well with our laboratory observations. They provide a basis for the design of practical instruments.

Magnetic head for effecting perpendicular magnetic recording

Abstract: In a magnetic head for perpendicular magnetization recording of a main magnetic pole exited type, a high permeability magnetic thin layer is held at its top portion by nonmagnetic supporter and the thin layer is closed by a first high permeability block. The thus constructed main magnetic pole is surrounded by a second high permeability block, and a third high permeability block is located in facing relation to the main magnetic pole and second high permeability material. This magnetic head has high recording and reproducing efficiency and well-shielded from external magnetic field. Some structural improvements are also provided so that leakage of magnetic flux, disconnection and short circuit of a coil are avoided.

Switched-mode power supply for supplying an inductor

Abstract: The invention relates to a switched-mode power supply for supplying an inductor in order to achieve a predetermined current response using a bridge consisting of electronic switches (2 to 5) in whose one diagonal the inductor (1) is located and to whose other diagonal a DC voltage source is connected, and having a control device (13) for driving the switches (2 to 5). For each current direction in the inductor (1), the two switches (which are located diagonally opposite one another between the positive terminal and negative terminal of the DC voltage source and the inductor (1)) are driven, for the rising current edge and current peak, in such a manner that one of these switches (for example 2) is continuously conducting and the second (for example 5) is pulsed. For each current direction in the inductor (1), the two switches which are located diagonally opposite one another between the positive terminal and negative terminal of the DC voltage source and the inductor (1) are driven, for the current falling edge, such that one of these switches (for example 2) is continuously switched off and the second (for example 5) is pulsed.

Electric power source for use in electrostatic precipitator

Abstract: An electric power source for use in an electrostatic precipitator includes a first high voltage DC source having an output terminal adapted to be connected to discharge electrodes of the electrostatic precipitator An inductor is connected at its one end through a coupling capacitor to the output terminal A controlled rectifier is connected at its an anode to the other end of the inductor and has a grounded cathode A diode is connected in a reversed parallel to the controlled rectifier There is also provided a second high voltage DC source having a high output impedance and connected to the inductor, and the controlled rectifier is turned on and off by a controller

Equivalent circuit for end-loaded piezoelectric bimorph actuators

Abstract: Following on Mason's equivalent circuit for a piezoelectric bar with a length-expansion mode, we have designed an equivalent circuit for a piezoelectric bimorph. A transformer with a transformation ratio with the dimension ‘‘length'’ allows us to construct a moment from a force and an arm. The total moment is transformed back into a force at the tip of the bimorph by a reduced transformer with the dimension of ‘‘inverse length''. A mass m attached to the tip of the bimorph can be represented as an inductor of inductance L = m, which can be placed in series with the inductance which represents the mass of the bimorph. The velocity of the mass can be calculated as the current through the inductor, and the displacement of the mass expressed as the time integral of the velocity. The dynamic behavior of the mass is calculated as a function of the frequency of excitation with an electric voltage V. The displacement is observed under a microscope as a function of frequency, and shows a close agreement b...

Magnetic ring for free piston rectilinear generators

Abstract: The generator comprises at least one coil surrounded by a magnetic circuit of an inductor for taking-off electrical power. The magnetic circuit forms a variable gap with a reciprocating mobile part moving between two positions. The mobile reciprocating part is made in the form of a magnetic ring made by sheets of ferro-magnetic material having a uniform thickness and width and being radially positioned. The distance between the sheets at the proximity of a residual gap is such that ferro-magnetic material in area of the residual gap represents from 50 to 80% of the sheets in the magnetic circuit of the inductor.

Flyback modulated switching power amplifier

Abstract: A flyback modulated switching power amplifier is described. The amplifier employs a waveform generator to produce an input signal and power switches capable of controlled conduction in one direction and uncontrolled conduction in the other. An inductor is coupled to the power source through the power switches so that flyback current can flow through a switch in its uncontrolled direction from the inductor when the switch is turned off. A conduction feedback circuit detects conduction by the switches and a comparator detects whether the output is "too high" or "too low" relative to the input signal. A logic control selectively activates the switches to control the output voltage, but not until the last switch to be turned off has stopped all conduction, including flyback conduction.

Programming and control device for modified lead ballast for HID lamps

Abstract: Improved programming and control device for modified lead ballast for HID lamp. The basic ballast comprises a high reactive transformer and capacitor connected intermediate the transformer and lamp. An additional inductor and AC switch connect in parallel with the capacitor and the switch is opened and closed to vary the lamp current to control lamp output. The improved device comprises a parameter measuring means which measures a lamp operating parameter and converts same into output electrical signals. These signals are compared to a reference signal to generate error signals. The error signals are integrated by a capacitor and a potential which is indicative of the integrated signals is slowly developed at one capacitor terminal. A ramp capacitor is charged each half cycle of energizing potential. When the ramp capacitor potential crosses over the potential displayed at the one terminal of the integrating capacitor, a comparator means generates an output signal. The output signal actuates a gate drive to turn a gate-controlled AC switch "ON", which decreases the current to the lamp for the remainder of the half cycle. When the apparatus is initially energized, the potential at the one terminal of the integrating capacitor never crosses the ramp capacitor potential so that the device initially is inoperative. The potential at the integrating capacitor terminal is then slowly changed by the integrated error signals to reflect to magnitude of the integrated error signals. Thus, the improved device is not effective until the lamp is normally operating.

Development of amorphous Fe-B based alloys for choke and inductor applications

Abstract: This paper describes a method of obtaining linear permeability characteristics from Fe-B based amorphous alloys, suitable for choke and inductor applications. The properties are developed by heat treatment at temperatures above those conventionally used to develop the optimum low or high frequency magnetic properties in these alloys. Within a narrow heat treatment temperature range it is possible to develop permeabilities of between 200 and 700, linear up to high flux density levels. D.C. Energy Storage Curves are presented for Fe 77.5 B 13 Si 9.5 alloy, toroidal tape wound cores, heat treated in this manner. These curves indicate the potential advantages of these cores over powder cores and gapped ferrites in D.C. choke applications.

Reversing-counterpulse repetitive-pulse inductive storage circuit

Abstract: A high-power reversing-counterpulse repetitive-pulse inductive storage and transfer circuit includes an opening switch, a main energy storage coil, a counterpulse capacitor and a small inductor. After counterpulsing the opening switch off, the counterpulse capacitor is recharged by the main energy storage coil before the load pulse is initiated. This gives the counterpulse capacitor sufficient energy for the next counterpulse operation, although the polarity of the capacitor's voltage must be reversed before that can occur. By using a current-zero switch as the counterpulse start switch, the capacitor is disconnected from the circuit (with a full charge) when the load pulse is initiated, preventing the capacitor from depleting its energy store by discharging through the load. After the load pulse is terminated by reclosing the main opening switch, the polarity of the counterpulse capacitor voltage is reversed by discharging the capacitor through a small inductor and interrupting the discharge current oscillation at zero current and peak reversed voltage. The circuit enables high-power, high-repetition-rate operation with reusable switches and features total control (pulse-to-pulse) over output pulse initiation, duration, repetition rate, and, to some extent, risetime.