Double-ended (i.e., Push-pull), Self-oscillating Type Patents (Class 363/22)
  • Patent number: 6055161
    Abstract: In a switching type power supply for use in an electric arc welder or plasma cutter, of the type having an output transformer with a primary winding in a series circuit DC source with a selected voltage and a switch, either single or tandem, with a conductive on state to pass a current pulse through the primary winding in a first electrical direction and a non-conductive off state disconnecting the DC voltage source from the winding and a large filter capacitor across the DC input voltage source, the improvement comprising: a snubber network for transferring energy due to the leakage inductance of the primary winding to the filter capacitor when the switch is shifted from the on state to the off state where the snubber network includes a storage capacitor with a diode controlled resonant charging circuit so the winding is in a tank circuit with the storage capacitor to charge the storage capacitor in a charging cycle when the switch shifts from the on state to the off state and a diode controlled discharging
    Type: Grant
    Filed: April 12, 1999
    Date of Patent: April 25, 2000
    Assignee: Lincoln Global, Inc.
    Inventors: Larry L. Church, Lifeng Luo
  • Patent number: 6028413
    Abstract: A device for charging batteries is comprised of a mobile electrical device MD and a charging unit CU and inductively transmits electrical power by means of a alternating magnetic field from at least one primary winding W1, W2 to at least one secondary winding W3, W4 in the mobile device MD. According to the invention, the alternating magnetic field is generated by a self-oscillating push-pull oscillator which contains switches Q1, Q2 that are reciprocally connected with positive feedback and in each push-pull branch, contains a resonance circuit with the effective inductance of at least one primary winding W1 or W2 and with a circuit capacitance C1, C3 or C2, C4, wherein the primary windings W1 and W2 in the charging unit CU are disposed spatially separate from each other so that each generates a magnetic alternating field in a different spatial region and the secondary windings W3, W4 in the mobile device are disposed so that each spatial region is equally loaded.
    Type: Grant
    Filed: September 18, 1998
    Date of Patent: February 22, 2000
    Assignee: Perdix Oy
    Inventor: Hans-Jurgen Brockmann
  • Patent number: 5923544
    Abstract: A noncontact power transmitting apparatus which makes it possible to rapidly charge a secondary cell of a part to be charged with large electric power and realize a lightweight and compact part to be charged. A power-transmitting coil of a charging part is divided into two sets, and the power-transmitting coils of the sets are respectively wound around cores, and are formed as a first power-transmitting coil portion 26 and a second power-transmitting coil portion 27 which are separate and independent as the two sets. Meanwhile, a power-receiving coil of a part to be charged is wound around a core, and is formed as a single power-receiving coil portion 28.
    Type: Grant
    Filed: July 21, 1997
    Date of Patent: July 13, 1999
    Assignee: TDK Corporation
    Inventor: Takashi Urano
  • Patent number: 5898577
    Abstract: An oscillator includes a converter, an oscillation transistor, a resistor, a capacitor and a primary coil of a transformer, and a rectifier includes a secondary coil of the transformer, resistors, capacitors, and a rectifying transistor. Control of the converter is carried out by the configuration of a capacitor, resistors and a transistor. A ripple filter includes a choke coil and ripple capacitors, and a converter activation part comprises a switch interlocked with a power supply switch and an activation diode. A ripple capacitor is also provided on the primary side of the converter. The battery is directly coupled to the primary side of the transformer.
    Type: Grant
    Filed: February 21, 1997
    Date of Patent: April 27, 1999
    Assignee: Sony Corporation
    Inventor: Yasuaki Tomiyama
  • Patent number: 5898580
    Abstract: The invention is about a dc/dc converter (1) fitted with switching means (11, 12) having a drive electrode (13, 14) each drive electrode (13, 14) being connected to polarization means (49,50). The switching means are to switch on and off a current coming from a direct source of current 2 and circulating in windings (17, 18, 5) of transformers (6, 7) of the converter. The improvement according to the invention comprises a protection circuit 24 connected to means (44) for detecting the value of current circulating in one of the windings (4, 5, 15, 19, 23) of the transformers. Outputs (47, 48) of circuit 24 are connected to the drive electrode (13, 14) of switching means (11, 12). Protection circuit (24) may be a bistable circuit that will lower voltage at its outputs (47, 48) in a permanent way if detected current has been to high, thus switching off in a permanent way switching means (11, 12).
    Type: Grant
    Filed: November 24, 1997
    Date of Patent: April 27, 1999
    Assignee: Thomson multimedia S.A.
    Inventor: Kum Yoong Zee
  • Patent number: 5801931
    Abstract: An inexpensive DC power source apparatus is provided which realizes a countermeasure against high frequency and redundant operation for improving reliability by using a simplified circuit construction to thereby reduce the number of parts. An input voltage follow type current controlled boosting chopper and a current feedback type self-running inverter are used in combination, and output voltage stabilization is accomplished by utilizing the voltage stabilizing function of the boosting chopper and current balance during parallel operation is accomplished by self-balance due to an impedance drop in the self-running inverter, thereby realizing the inexpensive power source apparatus in which the number of parts is reduced.
    Type: Grant
    Filed: December 5, 1995
    Date of Patent: September 1, 1998
    Assignee: Hitachi, Ltd.
    Inventors: Jiro Kino, Takashi Tabei, Masami Takahashi
  • Patent number: 5675491
    Abstract: This invention relates to a push-pull inverter used, for example, as a driver for cold-cathode discharge tube, hot-cathode discharge tube, etc. and comprises a boosting transformer including an input coil, an output coil and a feedback coil, and first and second switching elements for input coil current of this transformer, wherein the output of the boosting transformer is divided into a pair of output coil sections connected in series with each other and a conductor section lying between these output coil sections is circuit-arranged so that this conductor section be at the negative potential of the DC source.
    Type: Grant
    Filed: January 31, 1994
    Date of Patent: October 7, 1997
    Assignee: Kijima Co., Ltd.
    Inventor: Seiichi Kijima
  • Patent number: 5621621
    Abstract: A power unit including a self-oscillating series resonance converter which is intended to supply a load, for instance an electric bulb, a battery charger and/or electronic equipment. The series resonance converter includes two mutually connected transistors, each of which is activated by a respective control transformer, and further includes an inductor and a capacitor which are connected in series. Each transistor and an associated series-connected capacitive voltage divider and/or a further transistor are connected in parallel with the inductor, capacitor and control transformer. The load is connected across the capacitor. The magnetic flux through the control transformer can be influenced by a magnetic flux applied externally via an electromagnet to change the oscillation frequency of the transistors and therewith the voltage output of the power unit.
    Type: Grant
    Filed: December 18, 1995
    Date of Patent: April 15, 1997
    Assignee: Lindmark Electric AB
    Inventor: Magnus L. Lilliestrale
  • Patent number: 5621620
    Abstract: A converter for raising a weak input DC voltage of 0.3 volts or less to an output voltage has a blocking oscillator and a field-effect transistor included in the oscillator. The transistor having a base earthed is of the enhancement type activated by a gate-source voltage equal to or lower than the input, and the oscillator is activated responding to the gate-source voltage, so that pulses are generated as the output. Typically, the oscillator is composed of a resistor and a condenser connected in series through a lead and between an earth and an input line, a transformer whose secondary winding is connected to transistor's gate and the lead, with a primary winding being connected to the input line and the transistor's drain, and a diode earthed and having a cathode connected to the gate. An electromotive force induced through the secondary winding when the transistor is inactivated has positive and negative poles directed to the condenser and the gate, respectively.
    Type: Grant
    Filed: September 12, 1995
    Date of Patent: April 15, 1997
    Assignee: Kabushiki Kaisha Samy
    Inventors: Haruhiko Machida, Shinichi Tasaki
  • Patent number: 5600547
    Abstract: An inverter circuit that can provide a stable AC power supply by synchronizing the switching operations of a DC-to-DC converter and a DC-to-AC converter which constitute the inverter circuit with each other.The inverter circuit includes an error amplifier for comparing a feedback control voltage from the DC-to-AC converter with a reference voltage and amplifying the resultant voltage of comparison, a frequency synchronizing section for providing a sawtooth voltage synchronized with the frequency of a ripple voltage occurring at an output terminal of the DC-to-DC converter due to the switching operation of the DC-to-AC converter, and a comparator for comparing the sawtooth voltage with the output voltage of the error amplifier, and providing a switching control signal to the DC-to-DC converter as result of comparison.
    Type: Grant
    Filed: December 20, 1995
    Date of Patent: February 4, 1997
    Assignee: Samsung Electro-Mechanics Co., Ltd.
    Inventor: Joon H. Kim
  • Patent number: 5548502
    Abstract: To provide a resonant switching power supply switch with a simple structure and little noise, a push-pull resonant switching power supply circuit includes a transformer 104, a capacitor 105, two transistors 106a and 106b (bipolar transistors or field-effect transistors), and a bias circuit 201. The transformer 104 has a rectification circuit 340 connected to its secondary winding. The capacitor 105 forms a parallel resonant circuit in combination with the transformer 104. The transistors 106a and 106b are push-pull connected to the primary winding of the transformer 104 and the bases of which are connected to a feedback winding 104 of transformer. The bias circuit 201 applies a variable bias voltage to the base of the transistors.
    Type: Grant
    Filed: August 29, 1994
    Date of Patent: August 20, 1996
    Assignee: Hamamatsu Photonics K.K.
    Inventor: Mitsuo Kosugi
  • Patent number: 5428521
    Abstract: OBJECT: To provide a non-contact power supply apparatus capable of supplying stable power very efficiently even when changes in load at the receiving side occur by tuning AC frequency supplied to the oscillating circuit on the receiving side and the resonant frequency of the resonance circuit on the receiving side. CONSTITUENTS: At the receiving side is provided a resonance circuit 3 in which resonance coil L3 on the receiving side is connected in parallel with resonance capacitor C3. At the supplying side are provided a detecting coil L2 which detects resonant frequency of resonance circuit 3 on the receiving side and a control means 1 which tunes AC frequency supplied to the aforementioned oscillating circuit 2 on the supplying side with resonant frequency of the aforementioned oscillating circuit 3 on the receiving side according to the frequency of induced electromotive force detected by said detecting coil L2.
    Type: Grant
    Filed: October 19, 1993
    Date of Patent: June 27, 1995
    Assignees: Alps Electric Co, Ltd., Kigawa Electronic Engineering Laboratory, Inc.
    Inventors: Michio Kigawa, Shinichi Higuchi
  • Patent number: 5317497
    Abstract: An inverter circuit for providing an AC driver voltage for a capacitive load from a DC input voltage. The circuit uses a pair of balanced transistors supplying a split primary winding of a transformer, a feedback winding thereof being coupled thereto to supply a feedback signal to the transistor inputs. Resistors are used to optimize inverter efficiency by adjusting transformer saturation and the DC bias of the drive transistors. A capacitor is connected across the two primaries to provide harmonic suppression an aid in starting the inverter. A second capacitor, connected from base to collector of the transistors opposite the transistor with DC bias being introduced, provides suppression of undesirable high frequencies which will occur if this capacitor is not present. The AC output is supplied from the secondary winding of the transformer.
    Type: Grant
    Filed: May 18, 1992
    Date of Patent: May 31, 1994
    Assignee: Loctite Luminescent Systems, Inc.
    Inventor: Ronald E. Belek
  • Patent number: 5309066
    Abstract: A device to produce alternating electric current of high frequency for power consumers such as fluorescent lamps, which includes the means of supplying a DC voltage nearly twice the size of the peak voltage of the alternating voltage input--with negligible loss of power--to the remainder of the circuit and thus reducing the intrinsic power consumption of the device as well as making it possible to supply the said power consumer such as the fluorescent lamp with a higher start voltage as well as a higher voltage in operation.
    Type: Grant
    Filed: May 29, 1992
    Date of Patent: May 3, 1994
    Assignee: Jorck & Larsen A/S
    Inventor: Claes Ditlevsen
  • Patent number: 5225972
    Abstract: A power source driving an electrical device includes a DC power supply providing a rectified and smoothed DC voltage from an AC main power, a self-oscillator energized by the DC power supply to generate a high frequency voltage, and a transformer which provides an output voltage from the high frequency voltage for driving a load circuit of the device. The characterizing feature of the power source resides in that the self-oscillator comprises a class C amplifier and includes a bias stabilizing circuit which provides a stabilized bias to the class C amplifier for assuring constant and optimum operation irrespective of possible variations in the supply voltage as well as load variations.
    Type: Grant
    Filed: March 10, 1992
    Date of Patent: July 6, 1993
    Inventor: Hiroshi Sakamoto
  • Patent number: 5208739
    Abstract: An integrated magnetic power converter for supplying power to a load includes a continuous magnetic structure having first and second legs and a magnetic path therebetween. Two transformers and two inductor devices are included on the core. The converter operates in four states determined by the state of two switches coupled to the transformer.
    Type: Grant
    Filed: January 7, 1992
    Date of Patent: May 4, 1993
    Assignee: Powercube Corporation
    Inventor: Clayton L. Sturgeon
  • Patent number: 5162981
    Abstract: A circuit for converting on d.c. voltage to another d.c. voltage including a transformer having a center tap and first and second end leads. A d.c. source voltage is connected to the center tap of the transformer. The end leads are connected to ground through first and second MOSFETs and to the gate of the MOSFET through which the other end lead is connected to ground such that the circuit is nominally self-oscillating due to transformer saturation. Current spikes may be minimized with a control circuit, consisting of an oscillator, a flip-flop, and first and second transistors, connected to the gates of the first and second MOSFETs. The control circuit turns the MOSFETS off prior to their natural oscillation turn off caused by transformer saturation. The circuit is particularly suited to operation with a low voltage d.c. source and low voltage MOSFETS.
    Type: Grant
    Filed: May 30, 1991
    Date of Patent: November 10, 1992
    Assignee: Hughes Aircraft Company
    Inventors: James F. Lazar, Stephen J. Hulsey
  • Patent number: 5159540
    Abstract: A self-oscillating DC to DC voltage converter having improved efficiency. The high efficiency saturable core voltage converter 100 of the present invention provides an output voltage across an output load R.sub.L in response to the input voltage at a source node 106 of a voltage source 104. The present invention includes a transistor switching network 120, 122 coupled to the source node 106. The switching network 120, 122 generates an alternating voltage in response to oscillation of the flux within a magnetic core 116. A voltage transformer 110 then impresses an output voltage across an output load R.sub.L, thus providing a load current I.sub.L. The inventive converter 100 further includes a feedback winding 112 for providing a transistor drive current to the transistor switching network 120, 122. A portion of the transistor drive current is shunted to the source node 106 by a source feedback arrangement 126, 130.
    Type: Grant
    Filed: March 9, 1992
    Date of Patent: October 27, 1992
    Assignee: Hughes Aircraft Company
    Inventor: James Lee
  • Patent number: 5070439
    Abstract: A DC to DC converter employs a push-pull oscillator which employs a transformer having a primary winding and a plurality of secondary windings. The transformer has a core which is of a square loop hysteresis type. The push-pull oscillator is supplied operating voltage by means of a voltage regulator circuit which operates to regulate the voltage applied to the push-pull oscillator according to both input voltage variations and output load variations. An output secondary winding of the transformer is coupled to a full wave rectifier. The full wave rectifier output is fed back to the regulator to control the voltage applied to the push-pull oscillator via the regulator. Due to circuit operation, the output voltage is extremely well regulated while having low ripple.
    Type: Grant
    Filed: March 12, 1991
    Date of Patent: December 3, 1991
    Assignee: Rolm Corporation
    Inventor: Joseph D. Remson
  • Patent number: 5049788
    Abstract: A lighting circuit for a fluorescent lamp includes a D.C. power supply which is connected across a pair of series transistors. A transformer has first and second windings connected to the bases of respective transistors and a third winding connected between the junction of the transistor pair and a booster transformer. The filaments of the fluorescent lamp are connected through a choke coil to the booster transformer, and a capacitor is connected in resonant circuit with the choke coil.
    Type: Grant
    Filed: April 30, 1990
    Date of Patent: September 17, 1991
    Inventor: Sang-Woo Lee
  • Patent number: 5014182
    Abstract: A high frequency self-oscillating inverter including a snubber circuit for minimizing both turn-on and turn-off switching losses. The inverter converts a DC supply to an AC load current and includes a saturating transformer for alternatively driving first and second switching devices during subsequent unsaturated states. During the time the transformer is saturated, both switching devices are kept off.The snubber circuit includes a first capacitor across the first switching device, a second capacitor across the second switching device, and an inductance. During saturation the two capacitors and inductance form a resonance circuit, wherein the inductance has a resonant half sine wave current, one capacitor discharges, and the other capacitor charges.Turn off switching losses are made negligible by selecting capacitors such that the fall time of the corresponding switching device is much faster than the time to charge the capacitor to a significant voltage.
    Type: Grant
    Filed: April 19, 1989
    Date of Patent: May 7, 1991
    Assignee: Lambda Electronics Inc.
    Inventor: Itzchak Cohen
  • Patent number: 4935862
    Abstract: A device to produce alternating electric current of high frequency for power consumers such as fluorescent tubes comprises a transformer with a winding connected in series with an output terminal and active electronic components controlling the output current, said active components being controlled by electric voltages produced by inductive feed back. Magnetic saturation is utilized to modify the induction relationship in such way that the active components cyclically change the direction of the output current. According to the invention the feedback takes place in two magnetic cores, each core being equipped with at least one further electric magnetization winding designated a command winding, as electric current is fed through the command windings whereby magnetic saturation of the magnetic cores is controlled.
    Type: Grant
    Filed: October 30, 1987
    Date of Patent: June 19, 1990
    Assignees: Jorck & Larsen A/S, Halberg & Thomsen Elektronik L/S
    Inventors: Peer Herbsleb, Kjell Herbsleb, Kurt Halberg, Karl A. Jensen
  • Patent number: 4920471
    Abstract: The invention relates to a high voltage AC power supply which can be operated as either a constant current source with overvoltage protection or as a constant voltage source with current limiting protection. The power supply includes a sinusoidal transformer having a high turn winding and a sampling circuit on its secondary side for sampling voltage proportional to the load current. A comparator compares the sampled voltage to a reference voltage and supplies an error voltage to a buck regulator. The buck regulator converts the error voltage to a variable DC voltage which is fed to an oscillator formed by the primary winding of the transformer.
    Type: Grant
    Filed: March 11, 1988
    Date of Patent: April 24, 1990
    Assignee: Imagitek
    Inventors: Robert N. Livingston, Michael Kosteva
  • Patent number: 4887198
    Abstract: An electronic large current switch for a single power circuit has a DC-to-DC converter for low voltage transformation, the operation of which is controlled by a control switch or a periodic switching circuit and a switching transistor supplied with the low voltage output of the DC-to-DC converter as its base bias voltage and which controls the power supply to an electrical load circuit so as to be capable of minimzing the power loss of the switching transistor and making the product small and integrated.
    Type: Grant
    Filed: March 1, 1988
    Date of Patent: December 12, 1989
    Assignee: Jang B. Lee
    Inventor: Youn S. Lee
  • Patent number: 4858096
    Abstract: An impedance for short-circuit prevention is connected with a secondary winding side of a transformer of a resonant converter comprising a resonant circuit, a D.C. input source, and a switching devices. The short-circuit prevention impedance is driven by the driving current generated in a driving winding in accordance with a resonance current at the primary winding side of the transformer, thereby obviating the stop of an oscillation. The oscillation can be stopped at a timing of not generating a surge voltage in the switching devices by detecting a current returning to the D.C. input power source.
    Type: Grant
    Filed: April 6, 1988
    Date of Patent: August 15, 1989
    Assignees: Hitachi, Ltd., Hitachi Metals, Ltd.
    Inventors: Kenichi Onda, Yasuo Matsuda, Kojin Abe, Yasunori Iwafuji, Hiroyuki Aoyama, Hideo Yoshinaka
  • Patent number: 4811186
    Abstract: A power supply for an inert gas lamp which enables automatically changing the portion of the lamp which is lit in accordance with a predefined pattern. The power supply includes an a.c. to d.c. conversion circuit, and a high frequency-high voltage transformation circuit with an input coupled to the conversion circuit and an output to be coupled to an inert gas lamp. A control or function module controls and automatically changes the voltage supplied to the transformation circuit, in accordance with a predefined pattern, and thereby causes the portion of the lamp which is lit to change in accordance with that pattern. The transformation circuit and the control module are arranged so that the portion of the lamp which is lit can be smoothly and controllably varied from zero to 100 percent of the length of the lamp.
    Type: Grant
    Filed: February 25, 1988
    Date of Patent: March 7, 1989
    Inventor: Frank J. Vargo
  • Patent number: 4734828
    Abstract: In one embodiment, the high frequency-high voltage power module includes an output transformer having a first primary winding and a first secondary winding and a second transformer, that is saturable, having a second primary winding and a second secondary winding. The AC power applied to the power module is converted to a substantially direct current by a diode, a capacitor and a thermistor. A center tap on the first primary winding is connected to the positive side of the capacitor. Either end of the first primary winding of the output transformer is connected to a respective end of the second primary winding of the second transformer via a respective resistor. The center tap on the second secondary winding is connected via an RC circuit to the negative side of the capacitor. A pair of switching transistors operates in a balanced push-pull relationship and is switched by the current flowing through the divided windings of the second secondary winding.
    Type: Grant
    Filed: April 27, 1987
    Date of Patent: March 29, 1988
    Inventor: Frank J. Vargo
  • Patent number: 4658343
    Abstract: A fluorescent lamp driver employs a saturable reactor switch for producing a high-frequency, substantially symmetrical drive signal for igniting and driving a fluorescent lamp. The drive signal is applied to the filaments of a fluorescent lamp using a resonant drive circuit whose components are series resonant near the frequency of the substantially symmetrical drive signal. Before ignition, the resonant drive circuit applies substantially the entire drive signal voltage in series with the filaments as well as across the fluorescent lamp. Thus, the filaments are heated to release electrons which ionize the inert gas to initiate a gas discharge in the lamp. The high-frequency drive signal thenceforth maintains the gas discharge without permitting time for the ionized gas to recombine between half cycles of energization.
    Type: Grant
    Filed: April 3, 1986
    Date of Patent: April 14, 1987
    Inventor: Francis H. Shepard, Jr.
  • Patent number: 4628284
    Abstract: A push-pull current-fed parallel resonant oscillator includes a parallel resonant LC tank circuit with one end coupled to one terminal of a DC current source via a serially connected first diode and first switching transistor and the other end of the tank circuit coupled to said one terminal via a serially connected second diode and second switching transistor. Respective capacitors (17, 21) shunt the series connections. The tank circuit inductor includes the primary of a transformer whose secondary is part of the transistor drive circuit. The circuit parameters are chosen to provide a duty cycle less than 50% and a high voltage gain of the AC tank voltage. The transistors are controlled to delay the turn-off time of the on-transistor thereby allowing a negative voltage to develop on the opposite capacitor which in turn delays turn-off of its parallel connected transistor so as to provide a dead-time (.DELTA.t.sub.2) during the switching interval in which both transistors are simultaneously off.
    Type: Grant
    Filed: June 3, 1985
    Date of Patent: December 9, 1986
    Assignee: North American Philips Corporation
    Inventors: Gert W. Bruning, Mark W. Fellows
  • Patent number: 4609981
    Abstract: The converter comprises an output transformer (T1) through which pass trapezoidal current waves. The primary winding (A0) is supplied under the control of two control circuits (P1, P2), each comprising a transistor (Q1, Q2) and a diode (D1, D2) which are connected in anti-parallel. The two transistors are controlled by two oppositely-poled secondary windings (W1, W2) of a second transformer (T2), the primary winding (W3) of which is controlled by the first transformer (T1). Associated with each control circuit (P1, P2) is a capacitor (C1, C2) such as to accumulate energy during one phase of operation and to discharge it during a subsequent phase. Another winding (Wc) of the second transformer (T2) permits the latter to be biased, stabilizing the output voltages by means of closed-loop feedback control of one thereof.
    Type: Grant
    Filed: July 11, 1984
    Date of Patent: September 2, 1986
    Assignee: Ing. C. Olivetti & C., S.p.A.
    Inventor: Piero Gamba
  • Patent number: 4603307
    Abstract: An inverter (100) receives a DC voltage and generates therefrom a square wave output signal. The inverter includes an output transformer (T3) and a saturable core transformer (T4). The saturable core transformer (T4) provides base current for a first transistor (Q3) and a second transistor (Q4). The first transistor (Q3) and the second transistor (Q4) alternatively turn on and off, causing a square wave to appear across the secondary winding of the output transformer (T3). The primary winding of the output transformer is coupled to the collectors of the first and second transistors via a pair of windings (L10, L11) magnetically coupled to the saturable transformer (T4). A pair of diodes (D4, D5) are provided to prevent the output leads of primary windings of the output transformer (T3) from dropping below ground potential.
    Type: Grant
    Filed: February 12, 1985
    Date of Patent: July 29, 1986
    Assignee: Boschert, Inc.
    Inventors: William C. Voight, Arthur B. Odell
  • Patent number: 4553070
    Abstract: An electronic ballast for a discharge lamp (8) for restricting and stabilizing the lamps current. The ballast comprises a high frequency oscillator for connection to a D.C. supply which consists of two transistors (1,2) connected in series, with a base drive transformer (3) coupled between them to bring the transistors (1,2) into alternating phase operation. A resonance circuit connected in series with the primary winding (4) of the transformer (3), comprises an inductor (7), resonance capacitors (10 and 11) and a capacitor (9) coupled in parallel with the lamp (8). The lamp (8) is, in turn, connected in series with the resonance circuit. In addition, a filter capacitor (c) having a high charging ability is coupled between the terminals of the D.C. supply. The resonance capacitors (10 and 11) are connected in series between the terminals of the D.C.
    Type: Grant
    Filed: July 6, 1982
    Date of Patent: November 12, 1985
    Assignee: Oy Helvar
    Inventors: Martti Sairanen, Matti Virta
  • Patent number: 4519023
    Abstract: A self oscillating inverter including a DC to DC converter and method for control thereof which senses the onset of a transformer core saturation to control its operation without dependence thereon. Linearizing inductors in the transformer secondary function to maintain a ramp shaped collector current waveform under full load conditions to allow control of output voltage by varying the oscillator frequency.
    Type: Grant
    Filed: May 20, 1983
    Date of Patent: May 21, 1985
    Assignee: Motorola, Inc.
    Inventor: Theodore V. Lester
  • Patent number: 4474548
    Abstract: A combustion controlling apparatus is disclosed which is used in a pulse combustion apparatus for generating flames intermittently and which has a flame-rod type flame detector. In this combustion controlling apparatus, a low AC source voltage is converted to a DC voltage and then this DC voltge is converted by an inverter to an AC of about 100 V and 800 Hz which is then supplied to the igniter and flame rod. The inverter comprises a pair of transistors and a transformer having a primary winding with its center tap connected to a DC source voltage and both ends thereof connected to the respective collectors of the transistors which are in turn cross-coupled to the bases of the mating ones through respective series circuits each consisting of a capacitor and a resistor. Thus, in a secondary winding of the transformer, a rectangular wave voltage is produced. The inverter can supply a high voltage to the flame rod during ignition, enabling easy fire detection and can prevent the transistors from generating heat.
    Type: Grant
    Filed: June 11, 1982
    Date of Patent: October 2, 1984
    Assignee: Hitachi, Ltd.
    Inventors: Motoshi Miyanaka, Kenzi Toudo
  • Patent number: 4464710
    Abstract: A d-c to d-c converter which can start with a shorted output and which regulates output voltage and current is disclosed. Voltage controlled switches directed current through the primary of a transformer the secondary of which includes virtual reactance. The switching frequency of the switches is appropriately varied to increase the voltage drop across the virtual reactance in the secondary winding to which there is connected a low impedance load. A starting circuit suitable for voltage switching devices is provided.
    Type: Grant
    Filed: April 14, 1982
    Date of Patent: August 7, 1984
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventor: Robert P. Gruber
  • Patent number: 4441087
    Abstract: A high efficiency push-pull inverter circuit employing a pair of relatively high power switching transistors is described. The switching on and off of the transistors is precisely controlled to minimize power losses due to common-mode conduction or due to transient conditions that occur in the process of turning a transistor on or off. Two current feed-back transformers are employed in the transistor base drives; one being saturable for providing a positive feed-back, and the other being non-saturable for providing a intermittently negative feed-back.
    Type: Grant
    Filed: December 14, 1981
    Date of Patent: April 3, 1984
    Inventor: Ole K. Nilssen
  • Patent number: 4424556
    Abstract: A self-oscillating DC to DC converter which includes either two or four transistors, three transformers (a converting transformer, a driving transformer and a current transformer) and an inductance.The operating frequency of the converter is fixed by the saturation time of the driving transformer. The base currents of the transistors are mainly supplied by the current transformer so as to be in proportion to the collector currents of the transistors. The operating frequency of the converter is kept constant in spite of load fluctuations. The inductance which is connected in series between a winding of the converting transformer and a winding of the driving transformer. The inductance prevents the two or four transistors from being `on` simultaneously.
    Type: Grant
    Filed: August 13, 1981
    Date of Patent: January 3, 1984
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Mikio Maeda, Masahiro Kosaka, Katsuhiko Higashiyama
  • Patent number: 4390937
    Abstract: A self-starting transformer-coupled FET multivibrator is constructed to avoid net dc flow in the primary winding of its transformer, driven push-pull by the multivibrator FET's.
    Type: Grant
    Filed: June 17, 1981
    Date of Patent: June 28, 1983
    Assignee: RCA Corporation
    Inventor: Charles A. Clark, Jr.
  • Patent number: 4371918
    Abstract: To increase the efficiency of a push-pull saturation converter, a choke is introduced in a common emitter circuit of switching transistors in the converter. In addition, a constriction may be provided in a center leg of a transformer core of a switching transformer within the converter. To further improve efficiency, an RC acceleration element may be provided in a base circuit for the switching transistors.
    Type: Grant
    Filed: February 27, 1981
    Date of Patent: February 1, 1983
    Assignee: Siemens Aktiengesellschaft
    Inventor: Rudolf Schierjott
  • Patent number: 4334267
    Abstract: A power transformer of an inverter power supply has a primary winding coupled to a source of DC voltage. First and second transistor switches are coupled to the primary winding in a push-pull arrangement. A drive winding of a saturable transformer is coupled to the base electrode of each of the two transistor switches to alternately apply forward drive to each switch. A control winding of the saturable transformer is supplied with a control current that reaches a magnitude that magnetically saturates the core of the saturable transformer to remove forward drive from the conducting transistor switch for developing an alternating polarity output voltage across a supply winding of the power transformer. A capacitor and an inductor form a resonant circuit upon attainment of core saturation.
    Type: Grant
    Filed: October 20, 1980
    Date of Patent: June 8, 1982
    Assignee: RCA Corporation
    Inventor: Sandor Miko
  • Patent number: 4322789
    Abstract: The invention relates to static converters of the symmetrical type whose function is to convert an input direct current voltage into an output alternating current voltage of chosen frequency and power. The self-oscillator according to the invention is composed of two transistors mounted with a common emitter. The device is energized, for instance, from a main power supply unit, associated with a voltage limiter circuit, which subjects the output power of the device to any parameter. The capacitive power factor of the device is compensated by an inductance connected in series with the main power supply. The device according to the invention can replace, advantageously, the conventional "ballast" for fluorescent lamps.
    Type: Grant
    Filed: June 26, 1980
    Date of Patent: March 30, 1982
    Assignee: Mere, Malleray & Cie
    Inventor: Henri Courier de Mere
  • Patent number: 4322788
    Abstract: A control circuit for an inverter includes a DC voltage source having first and second terminals, an input transformer having a primary winding, a pair of secondary windings and a magnetic core, an output transformer having a primary winding, a secondary winding and a feedback winding, first and second transistors each having a control electrode, the main current paths of which are connected, through the primary winding of the output transformer, between the first and second terminals of the DC voltage source and the control electrodes of which are connected to the pair of secondary windings of the input transformer, coupling circuit for connecting the primary winding of the input transformer to the feedback winding of the output transformer, a starting circuit for putting one of the first and second transistors in its conductive state when the DC voltage source is operated, and a control circuit including at least a shorting winding provided in connection with the magnetic core of the input transformer so as
    Type: Grant
    Filed: May 8, 1980
    Date of Patent: March 30, 1982
    Assignee: Sony Corporation
    Inventor: Tadao Yoshida
  • Patent number: 4319315
    Abstract: A D.C. to D.C. converter is disclosed which includes a first and a fourth, and a second and a third, sequentially operating transistors. The D.C. to D.C. converter further includes a saturable transformer having a center-tap and resistive networks interposed among the four transistors. The D.C. to D.C. converter is adapted for energization by an input D.C. voltage. The transistors of the D.C. to D.C. converter cause one side of the input D.C. voltage to be sequentially applied to opposite sides of a primary winding of the transformer which, in turn, cause the transformer to be sequentially excited into positive and then negative saturation conditions. The sequential excitation of transformer develops a time varying square-wave type signal at the secondary windings of the transformer which is further converted into a D.C. signal by an A.C. to D.C. converter.
    Type: Grant
    Filed: October 9, 1980
    Date of Patent: March 9, 1982
    Assignee: General Electric Company
    Inventors: Marvin F. Keeney, Jr., William A. Massey
  • Patent number: 4318170
    Abstract: A power inverter oscillator circuit has an output transformer with a primary winding, coupled in parallel with a capacitor, and the opposite ends of which are connected to the respective emitters of a PNP and a NPN transistors. The collector of the NPN transistor is coupled to the positive terminal and the collector of the PNP transistor is coupled to a negative terminal. In addition, a switching transformer is provided having a primary coil coupled at one end to one terminal and at the other end to the emitter of the transistor which is coupled to the other terminal. The switching transformer has two secondary coils or windings wherein one of the secondary coils is coupled between one terminal and the base of the transistor whose collector is coupled to the other terminal and the other secondary coil is coupled between the base of the other transistor and the remaining terminal.
    Type: Grant
    Filed: January 12, 1981
    Date of Patent: March 2, 1982
    Inventor: Rolando V. Cabalfin
  • Patent number: 4314327
    Abstract: A D.C. to D.C. voltage converter is disclosed that operates with various applied D.C. input voltages, each having a different voltage level, to develop a desired D.C. output voltage. The D.C. to D.C. voltage converter has a saturable transformer that is sequentially excited into its positive and negative saturation conditions under control of sequentially operating first and second transistor diode combinations. The D.C. to D.C. converter has a base drive current circuit comprised of a full-wave rectifier and a multiple level current limiting circuit. The base drive current circuit is interposed between a base drive winding of the saturable transformer and the base electrodes of the transistors of first and second transistor diode combinations. The base drive circuit adapts the saturation condition of the first and second transistor diode combinations to the level of the applied D.C.
    Type: Grant
    Filed: November 17, 1980
    Date of Patent: February 2, 1982
    Assignee: General Electric Company
    Inventor: Robert P. DePuy
  • Patent number: 4307353
    Abstract: An improved high efficiency push-pull inverter circuit employing a pair of switching transistors that are alternately triggered into conduction by a control circuit, for converting DC voltage into high frequency AC voltage. The control circuit includes a pair of saturable transformers that are non-coupled to each other and are each connected to the base of a respective transistor. The bases are isolated from ground potential by a capacitor, and significant reverse voltage signals are developed and alternately applied to the base of a conducting transistor for rapidly turning it off, thereby increasing device switching speed and overall efficiency of the circuit.
    Type: Grant
    Filed: December 14, 1979
    Date of Patent: December 22, 1981
    Inventor: Ole K. Nilssen
  • Patent number: 4296461
    Abstract: A battery package having a casing which contains at least one electrochemical cell electrically connected to a DC to DC converter. A pair of electrical connections are located on the casing to electrically connect the battery package to a load. The converter conducts and the cell discharges only when a load is present across the electrical connection.
    Type: Grant
    Filed: January 29, 1979
    Date of Patent: October 20, 1981
    Assignee: Duracell International Inc.
    Inventors: Henry R. Mallory, Steven J. Nichols
  • Patent number: 4184128
    Abstract: High efficiency push-pull inverters minimize undesirable energy losses usually resulting from simultaneous conduction and imperfect switching of the transistor switching means. In each of the disclosed circuits, a saturable inductor and a diode are connected in parallel and across the base-emitter junction of each transistor. Voltage on the base of each transistor causes its associated saturable inductor to saturate, and the saturated inductor then terminates the flow of base current and provides a path for rapid evacuation of the charge carriers stored in the transistor base-emitter junction in order to render the transistor rapidly non-conductive. Each diode provides a drain path for current continuing to flow through its associated saturable inductor after junction evacuation. A novel triggering means initiates oscillation of the inverters.
    Type: Grant
    Filed: March 20, 1978
    Date of Patent: January 15, 1980
    Inventor: Ole K. Nilssen
  • Patent number: 4103356
    Abstract: A synchronization circuit for a free-running push-pull inverter in which the frequency is determined by a saturable transformer in the feedback loop. Synchronization is achieved by momentarily short-circuiting the inputs to the two switching transistors together to initiate the switching cycle.
    Type: Grant
    Filed: November 23, 1976
    Date of Patent: July 25, 1978
    Assignee: Northern Telecom Limited
    Inventor: John Reid Finlay
  • Patent number: RE31758
    Abstract: High efficiency push-pull inverters minimize undesirable energy losses usually resulting from simultaneous conduction and imperfect switching of the transistor switching means. In each of the disclosed circuits, a saturable inductor and a diode are connected in parallel and across the base-emitter junction of each transistor. Voltage on the base of each transistor causes its associated saturable inductor to saturate, and the saturated inductor then terminates the flow of base current and provides a path for rapid evacuation of the charge carriers stored in the transistor base-emitter junction in order to render the transistor rapidly non-conductive. Each diode provides a drain path for current continuing to flow through its associated saturable inductor after junction evacuation. A novel triggering means initiates oscillation of the inverters.
    Type: Grant
    Filed: February 5, 1982
    Date of Patent: December 4, 1984
    Inventor: Ole K. Nilssen