Abstract: A voltage boost circuit having a voltage output and a single input receives a DC voltage from an external source which is fed to an inductor. The input voltage is boosted to provide a constant voltage at the output at a level higher than the voltage input. A switch is coupled to the output of the inductor for controlling current through the inductor to induce a boosted voltage across the inductor.

Abstract: A filter network adapted to be placed in parallel with a power supply which acts like a short circuit at a specified frequency range above 80 kHz. The filter network comprises a plurality of parallel circuits, each of which comprise a capacitor, an inductor and a resistor in series with a second resistor coupled in parallel with the inductor.

Abstract: A voltage regulator for producing an output voltage that selectively tracks a logic voltage or a reference voltage and method of operating the voltage regulator. The voltage regulator has a diode OR with a logic and reference transistors. The logic voltage is scaled to be close in value to the reference voltage, if the two are not close in value. When the scaled logic voltage is larger than the reference voltage the logic transistor is on, turning off the reference transistor and passing the logic voltage to the output of the diode OR. When the scaled logic voltage is smaller than the reference voltage the logic transistor is off and the reference transistor is on, passing the reference voltage to the output of the diode OR. The voltage at the output of the diode OR is then compared in a comparator with the voltage at the output of the voltage regulator, which is scaled by the same factor as the logic voltage.

Abstract: The DC power supply disclosed herein is adapted to be energized from AC supply mains and incorporates a DC to DC switching inverter provided with an energy storage or filter capacitor for supplying an input voltage to the inverter. The capacitor is charged from the AC supply mains through a rectifier. A semiconductor switching device is interposed between the AC supply mains and the capacitor. A sensing circuit actuates the switching device to disconnect the capacitor from the supply mains when the voltage applied to the capacitor exceeds a pre-selected level.

Abstract: A piezoelectric ink jet printing system including a primary ink supply and a plurality of piezoelectric ink jet printhead assemblies. Each assembly comprises a housing, a piezoelectric ink jet printhead in the housing, a secondary ink supply attached to the housing close to the printhead, and a short ink supply line for delivery of ink from the secondary ink supply to the printhead. The system further includes a pump for pumping ink from the primary ink supply to the secondary ink supply of each printhead assembly. Each printhead assembly is operable independently of the other printhead assemblies and are selectively movable with respect to the other printhead assemblies and with respect to the primary ink supply so that each printhead assembly can be positioned at a desired location without regard to where the other printhead assemblies are to be positioned and without regard to where the primary ink supply is positioned.

Abstract: A trimmable voltage regulator feedback network is arranged as a voltage divider: series-connected resistors are connected between the divider tap and the regulator's output voltage and a fixed resistance is connected between the tap and ground. Severable links are connected across at least two resistors above the tap to allow the regulator output voltage to be trimmed in linearly independent increments with each severed link, thereby simplifying the task of determining which links to sever to attain a desired output voltage. A trimmable resistance is inserted between the divider tap and the circuit being driven to enable the impedance of the network to be adjusted. A regulator including the novel feedback network can provide a temperature-compensated output over the full range of selectable output voltages.

Abstract: The invention is a converter-fed drive system having at least one drive motor fed by a converter unit. The converter unit has a valve assembly containing semiconductor valves, a cooler for cooling the semiconductor valves and a capacitor assembly are mounted directly on the drive motor. There is also an inductor assembly, that is electrically connected to the converter unit, but is installed such that it is spatially separated from the converter unit and the drive motor. The cooler is simultaneously used to cool the drive motor as well as the converter unit.

Abstract: Switching power supplies are employed in electronic equipment using batteries as the power source, for the purposes of operating such equipment with a smaller number of batteries and of extending battery life. A switching power supply can efficiently supply stable voltages even when the battery voltage is lower or higher than the load voltage. Two mutually inverted triangular waves are generated by two triangular-wave generator circuits. Signals proportional to the voltage level from either a primary switching circuit for stepping down the input voltage or a secondary switching circuit for stepping up the input voltage are compared against the two triangular waves and pulse signals are generated. Using these pulse signals, the primary and secondary switching circuits are controlled.

Abstract: A boost mode controller with start up circuit includes: an inductor 12; a transistor 10 coupled to a first end of the inductor 12; a diode 16 having an anode coupled to the first end of the inductor 12; a capacitor 14 coupled to a cathode of the diode 16; a logic circuit 22 having an output coupled to a control node of the transistor 10; a comparator 28 having an output coupled to a first input of the logic circuit 22, a first input of the comparator 28 coupled to the capacitor 14, and a second input of the comparator 28 coupled to a reference node; and a counter 20 having an active low reset coupled to the output of the comparator 28 and an output coupled to a second input of the logic circuit 22.

Abstract: A plant for transmitting electric power between at least two alternating voltage networks which are each connected through a station to a direct voltage network for high voltage direct current. The stations transmit power between the direct voltage network and the respective alternating voltage networks. At least one VSC converter is in each station to convert direct voltage to alternating voltage and the converse. A cable with an insulating layer of polymer base surrounding a conductor forms the direct voltage network connecting the stations.

Abstract: A reference circuit (200') has bipolar transistors (216, 226) providing a voltage difference .DELTA.V of base-emitter voltages .vertline.V.sub.BE .vertline. and has resistors (210/R.sub.1, 220/R.sub.2) for adding a current I.sub.R1 resulting from .DELTA.V and a current I.sub.R2 resulting from of base-emitter voltage .vertline.V.sub.BE .vertline. of one bipolar transistor (216 or 226) so that a resulting temperature coefficient TC.sub.TOTAL of said currents I.sub.R1 and I.sub.R2 is compensated. The circuit (200') has voltage transfer units (260, 270) which transfer .DELTA.V to the resistors (210/R.sub.1, 220/R.sub.2) so that the resistors (210/R.sub.1, 220/R.sub.2) do not substantially load the bipolar transistors (216, 226). The voltage transfer units (260, 270) have input stages with n-channel FETs. A control unit (241) which is coupled to the bipolar transistors (216, 226) adjusts input voltages (.vertline.V.sub.CE .vertline.

Abstract: Power supply apparatus according to the present invention may comprise a direct current source and a phase-shift converter circuit connected to the direct current source. A rectifier is connected to the output of the phase-shift converter circuit and rectifies a modulated output signal produced by the phase-shift converter circuit. An average current sensor connected to the rectifier senses the time average current in the rectifier and produces an average current feedback signal. A control device connected to the average current sensor and to the phase-shift converter circuit is responsive to the average current feedback signal and operates the phase-shift converter circuit in accordance with the average current feedback signal.

Abstract: The present invention relates to a switching device for selecting a voltage between an a.c. voltage and a d.c. voltage using the ground as a reference, meant to be controlled by a two-state signal, using the ground as a reference and of the same sign as the d.c. voltage, including means for adjusting the turn-on time of a switch in the selection of the d.c. voltage.

Abstract: A regulator includes a driver stage having an output port for providing an output voltage, a predriver coupled to the driver to control the output voltage provided by the driver stage, a comparator to compare the driver output voltage to a reference voltage, and a feedback element coupled between the driver output port and the comparator. The driver may include a high side transistor having a collector coupled to a collector of a low side transistor, and a current sensing transistor having a base coupled to a base of the low side transistor.

Abstract: For use in a switch-mode power converter including parallel-coupled first and second switches, the first switch having a temperature-dependent resistance, a circuit for, and method of, distributing current between the first and second switches. In one embodiment, the circuit includes a device having a temperature-dependent characteristic, in thermal communication with the first switch and electrically coupled to a gate of the first switch, that senses a temperature of the first switch, modulates an amplitude of a drive waveform applied to the gate based on the temperature and thereby redistributes the current.

Abstract: A power supply control device, by which a plurality of switching power supply circuits of different properties are operated under switching conditions respectively fitted therefor simultaneously with the prevention of an occurrence of what is called a low-frequency switching beat phenomenon, thereby achieving the miniaturization and the increasing of the efficiency of a power supply unit. To synchronize the timing of switching operations among control systems or units of the power supply control device, the control device of the multi-channel type or the control device having a master-slave function is used. Further, a frequency divider circuit or a frequency multiplier circuit is connected to a comparator of such a control device. Thereby, although synchronizing the timing among the switching operations, a plurality of pulse output signals of different frequencies are outputted from the control systems or the control units.

Abstract: The invention relates to a power modulator of pulse transformer type. The pulse transformer includes at least one secondary winding and a number of primary windings. The primary windings share a common ground terminal, but each "hot" terminal is independently connected to a respective dedicated pulse generating module, which includes a pulse switch, such as an IGBT-switch, connected to an energy storage capacitor. The pulse switch is electronically controllable at turn on and turn off, and eliminates the need for Pulse Forming Networks. The electronic pulse switch control is preferably used in combination with pulse voltage droop-compensating circuits that connect the switches to the primary windings. Furthermore, the transformer design is such that each primary winding only surrounds a portion of the total magnetic core cross section, giving an effect of a fractional turn primary.

Abstract: A method and a circuit arrangement for shaping any actual a.c. voltage characteristic into any reference a.c. voltage characteristic are described, which store the excess power in voltage overshoots in the form of a current in a current storage device using power electronic switching elements, and thus they compensate for the power deficiency when there is a voltage shortfall. The power electronic switching elements are driven by a digital automatic state machine through appropriate control pulses so that there is no fixed switching rate. The preferred field of application is for active filtering of the voltage of an electric three-phase or a.c. power supply system.

Abstract: A current-mode control device for controlling an output voltage of a DC power supply including: a switching element for supplying an output voltage of the DC power supply through an on/off switching action; an output voltage detector circuit for detecting the output voltage of the DC power supply and outputting an output voltage based on the output voltage of the DC power supply; a current sense circuit for converting into a voltage a switching current flowing through the switching element during the switch-on period of the switching element to sense and output the resulting voltage; an integrating circuit for converting the switching current of the switching circuit that increases at a gradient of a straight line linear function with time during of the switch-on period of the switching element into a voltage that increases at a rate defined by a quadratic or higher-order curved line with time by integrating the switching current of the switching circuit at least once and for superimposing the resulting volta

Abstract: A flyback converter including a transformer (6) having a primary winding (4) and a switching transistor (2), arranged in series therewith; control device (14) for closing the switching transistor (2) during a primary interval and opening the switching transistor (2) during a secondary interval in response to a control signal (U.sub.c), an auxiliary winding (12) for generating a feedback signal (U.sub.FB), measurement device (20) for unidirectionally measuring the feedback signal (U.sub.FB), a comparator (16) and a logic circuit (18) for deriving from the feedback signal (U.sub.FB) a first timing signal (TM.sub.1) which is representative of the secondary interval; comparison device for comparing the unidirectionally measured feedback signal (I.sub.FB) with a reference signal (I.sub.R) during the secondary interval, and an integrator (28) for generating the control signal (U.sub.C) in response to the comparison.