Abstract: A power conversion circuit, in which a flyback converter is modified with additional elements to provide both dissipationless snubbing and also input ripple cancellation. This is achieved by appropriate connection of an additional winding to the isolating transformer, without any need for a second transformer. The configuration of the secondary is conventional, and the switching transistor is connected in series with the primary winding across DC inputs (taken e.g. from a full-wave-rectified line voltage). The additional winding is connected on the primary side, and preferably has a near-unity turns ratio with the primary which is the inverse of the coupling coefficient. However, the additional winding is not connected between the two DC inputs, but instead has one end coupled through an intermediate capacitor to the corresponding end of the primary, and the other end coupled through a capacitor to the negative DC input.

Abstract: A current reference circuit includes a first, current mirror transistor having a gate coupled to a first feedback node, a source coupled to a first supply terminal and a drain forming a first reference node. A second, current mirror transistor has a gate coupled to the first feedback node, a source coupled to the first supply terminal and a drain forming a second reference node. A third transistor has a gate coupled to a second feedback node, a source coupled to a second supply terminal and a drain coupled to the first reference node. A fourth transistor has a gate coupled to the second feedback node, a source coupled to the second supply terminal and a drain coupled to the second reference node. A first operational amplifier has a first input coupled to the first reference node, a second input coupled to a bias node and an output forming the first feedback node.

Abstract: A tap changing circuit has each tap of a power transformer connected with a selector vacuum switching cell. The odd numbered cells and the even numbered cells are connected to respective sides of a load switch each including a further vacuum switching cell. The sides are bridged by a transition inductor or resistor.

Abstract: A method of recognizing armature impingement in an electromagnetic actuator having an electromagnet including a solenoid, an armature movable toward and away from the electromagnet and return means for exerting a force on the armature. The method includes the steps of maintaining a solenoid current at a predetermined magnitude I.sub.max during a predetermined period T.sub.A for capturing the armature at the electromagnet; switching off the solenoid current at a moment t.sub.1 upon lapse of the period T.sub.A ; upon lapse of a period T.sub.1 running from moment t.sub.1, oscillating the solenoid current between a lower holding current threshold I.sub.H1 and an upper holding current threshold I.sub.H2 ; detecting a current course from moment t.sub.1 ; and deriving a signal from such current course.

Abstract: The present invention relates to a variable voltage regulator that can be easily adjusted via a jumper, or a signal (provided by another circuit) so that the variable voltage regulator can provide at least one of a plurality of discrete voltages to an integrated circuit, such as a microprocessor. This is useful when a replacement microprocessor requires a different operating voltage than the microprocessor it replaced.

Abstract: The secondary winding is connected, via the series circuit of a capacitor and a second diode, to the charging capacitor which delivers the operating voltage. The centre point of the series circuit is connected to earth via a third diode. This enables energy to be recovered, in that the energy stored in the capacitor is delivered back to the charging capacitor during the inhibiting phase of the switching transistor.

Abstract: Method of optimizing a reproduction of a picture copy includes scanning a picture copy optoelectrically for generating scanning signals, in accordance with the scanning signals, electronically screening the picture copy and inscribing a recording medium so that one of a plurality of screen fields on the recording medium corresponds to one or more scanning signals of the picture copy, forming each of the screen fields, respectively, of a plurality of elementary cells, and determining relative locations of the elementary cells so that a region of overlap between an inscribed and an adjacent non-inscribed elementary cell, respectively, is minimal.

Abstract: A physical construction of an inverter of the type having a positive voltage line and a negative voltage line interconnected by one or more switch sections. Each section includes two switch circuits, each having a transistor in parallel with a diode. The two switch circuits are connected in series, with the connection between the circuits providing an output to drive a load. The positive voltage line includes a positive voltage rail positioned closely to a negative voltage rail which is part of the negative voltage line. The close proximity of the two rails causes an electrical coupling between the positive and negative voltage lines. Current paths including circuit traces and bond wires within the inverter are arranged to place paths having oppositely directed currents, or equal and opposite di/dt's, in close parallel proximity resulting in mutual coupling and reduction in parasitic inductances.

Abstract: An appliance timer has features to facilitate automated assembly or manual assembly. A timer housing base accepts timer components from two directions, and installation of components in either direction is along a straight axis. A motor in the timer engages a gear train which runs a drive cam. The drive cam imparts motion to a camstack which then engages timer blade switches, and the blade switches operate the appliance. A subinterval is also supplied on the timer to allow periodic operation of a switch without the use of the camstack. The timer also features a quiet manual advance which removes the blade switches from communication with the camstack to allow an operator to select various timer programs without any of the clicking noises that are usually associated with timer program selection. Furthermore, a detent slider is positioned in communication with the camstack to provide a tactile feel for the operator of the timer when selecting between various timer programs.

Abstract: A novel switching mode power supply (SMPS), which is capable of substantially reducing the response time of the SMPS for generating a plurality of regulated DC output voltages from an AC input power, comprises a first rectifier for rectifying the AC input power to produce a rectified AC power signal within a predetermined range; a transforming device for generating a plurality of scaled-down AC power signals from the rectified AC power signal; a second rectifier for producing and providing a plurality of regulated DC output voltages from the plurality of scaled-down AC power signals to the plurality of loads through respective load lines connected thereto; and a unit for grounding the rectified AC power signal previously charged in the first rectifier if there occurs a disruption in the supply of the AC input power to the SMPS, to thereby promptly produce the plurality of regulated DC output voltages when the supply of the AC input power is resumed.

Abstract: Engine driven turbines respectively drive separate propulsion and service ternators to supply power to propulsion motors and service equipment on naval combat ships through propulsion and service controls. Rechargeable batteries are connected through the service controls to the service alternators and to service loads through dc bus lines. The propulsion controls interconnect the propulsion motors with the propulsion alternators to which the electrically operated weapons are also connected through rectifiers and a pulse forming network.

Abstract: A device for switching an electric motor, particularly for braking an electrically operated tool, comprises change-over switches 19' and 20' for connecting and disconnecting the electric motor to and from an associated power source, for reversing the polarity of a field winding or armature winding of the electric motor, and for enabling and disabling an electric braking circuit for the electric motor, also an actuating member 21' for the change-over switches 19', 20', a movable contact 32', which is associated with each change-over switch and is movable between a fixed ON contact 30' and an OFF contact 30, which is spaced an arcproof distance from said ON contact, and a sliding guide 40', which is associated with at least one movable contact 32' and is adapted to guide said movable contact over at least part of its path of movement during the switching operation. The actuating member consists of a switching slider 21', which cooperates with a toggle lever 54.

Abstract: A method of switching an electromagnetic actuator which includes an armature movable along a path of travel and two electromagnets having respective solenoids, disposed at opposite ends of the path of travel for alternatingly attracting the armature. The method includes the steps of alternatingly applying a supply voltage to the electromagnets for alternatingly causing a supply current to flow therethrough for effecting a reciprocating motion of the armature; and applying an induced current, generated by an induced voltage appearing across one of the solenoids upon removal of the supply current from the one solenoid, to the other of the solenoids until the supply voltage applied to the other solenoid is greater than the induced voltage and the supply voltage across the other solenoid is capable of maintaining an attained current flow therethrough.

Abstract: A two level inverter having a switching element the switching frequency of which is higher than that of GTO, and providing a continuous control substantially over a full range of output voltages wherein the two level inverter comprises as its pulse modes an asynchronous bipolar modulation mode, a multi-pulse mode of an overmodulation mode, and a one pulse mode, and wherein advantageously the multi-pulse mode and the one pulse mode are arranged to be changed, thereby to enable a continuous control of its output voltage and reduce tone changes in the magnetic noise as well.

Abstract: A current mirror uses an operational amplifier to control the collector voltage of two mirroring transistors during operation. The operational amplifier is coupled to the collector of each mirroring transistor such that a differential in voltage between the collector will produce an output voltage which drives a MOS transistor. The MOS transistor, responsive to the output of the operational amplifier, adjusts the voltage at the collector of one of the mirroring transistors to restore equilibrium.

Abstract: A current-mode control system for a switching power supply which provides logarithmic compensation to a peak primary current of a variable frequency, fully discontinuous switching power supply. A ramp voltage generator generates a ramp voltage that is furnished to a control circuit. The control circuit compares the voltage level of the ramp signal to the voltage level of a control voltage. The control voltage is provided by an error amplifier and is a function of an output voltage of the converter. The control circuit allows a primary switching current to exist in the converter until the ramp voltage renders the control voltage. The ramp voltage logarithmically compensates the peak of the primary current by adjusting the ramp voltage. This logarithmic compensation provides a relatively constant output power over a large input voltage range.

Abstract: An active filter for compensation of polluting harmonics on an electricity distribution network comprising a source of energy (19, 20), a bridge converter (21) connected between the energy source and the network, control means which control the bridge converter in order to compensate for the polluting harmonics, characterized in that the state of the energy source (19, 20) is independant of the control of the bridge converter carried out by the control means (22) and in that the control means (22) control the injection of the harmonic components independantly of the state of the energy source.

Abstract: Power-supply apparatus for powering a control circuit for controlling a power switch component, the apparatus powering said circuit from the voltage across the terminals of the component in the off state, and including an energy-storage capacitor, said apparatus further including means for charging said energy-storage capacitor during the periods in which said component is on.

Abstract: A voltage balancing circuit and methods are disclosed for providing power from a single DC power supply to a circuit, such as an integrated circuit, that presents both a positive load and a negative load to the power supply, while ensuring that the positive load voltage and the negative load voltage remains substantially equal in magnitude, notwithstanding variations in the magnitudes of the loads. A voltage divider circuit provides a reference voltage equal to one-half of the total power supply voltage. Capacitors are provided across each of the positive and negative loads.

Abstract: A current-fed DC-to-DC converter (10) includes an input choke (20) which reduces current fluctuation in the converter (10). A power transformer (26), which is coupled to the input choke (20), transforms electrical energy at one voltage magnitude into electrical energy at another voltage magnitude. A first output rectifier (32) is coupled to the input choke (20). A second output rectifier (34, 36) is coupled to the power transformer (26). A first isolation diode (38) and a second isolation diode (40, 42) are coupled to the anodes of the first output rectifier (32) and the second output rectifier (34, 36), respectively. A transient voltage suppression element (12) is coupled to the first isolation diode (38) and the second isolation diode (40, 42).