Abstract: A zero-current switching converter converts power from an input source for delivery to a load. In the converter, a switch opens and closes at times of essentially zero current to enable energy transfer back and forth between said input source and said converter. A controller is connected to control the switch to initiate, during a first portion of each of a succession of converter operating cycles, forward energy transfer from said input source; and in at least some of said converter operating cycles, also to initiate reverse energy transfer to said input source at times not contiguous with said first portion.

Abstract: In connection with converting power from an input source for delivery to a load, a quantized converter has a switch which is controlled to undergo transitions between conductive and non-conductive states in each of a series of converter operating cycles. A switch controller reduces an error between (i) an actual time of occurrence of a particular one of the transitions in one of the operating cycles and (ii) a desired time of occurrence of the particular transition, based upon information about a prior error in timing which occurred in a previous one of the operating cycles.

Abstract: The invention features soldering parts (e.g., printed circuit boards) by indexing the parts sequentially and continuously through a series of processing stations. Each of the series of processing stations includes at least one processing position, and the indexer indexes the parts from processing position to processing position. At different processing stations, the parts indexed into those processing stations are simultaneously processed.

Abstract: A structure includes a baseplate, a circuit board parallel and adjacent to the baseplate, and an electronic component. The circuit board has an edge with a scallop formed in the edge, and the scallop is plated with a conductive material. The electronic component includes a power-dissipating surface and a pad for making electrical connection. The electronic component is mounted with the power-dissipating surface in contact with the baseplate and the pad electrically connected to the conductive material.

Abstract: A power conversion circuit has a port for connection to a power source; a transformer having a primary winding, a secondary winding, and an effective secondary leakage inductance L2e; and a capacitance C connected on a secondary side of the transformer. A first switching device is connected to be opened and closed to transfer energy from the power source via the effective leakage inductance to charge the capacitance during energy transfer cycles having a characteristic time scale of pi*sqrt(L2e*C). Control circuitry controls precharging of the capacitance at selected times other than during the forward energy transfer cycle.

Abstract: AC-DC boost switching power conversion apparatus delivers power from a bipolar input voltage source to a load at a unipolar load voltage without including rectifiers directly in the path of the current which is delivered from the input source. By this means the converter exhibits lower power loss in semiconductor diodes and switches than is exhibited by prior art converters which interpose a rectifier between a bipolar source and a DC-DC boost converter. Power processing is performed by circuitry of the kind which includes an inductive element in series with the bipolar input source, shunt paths which include switching elements for recirculating a bipolar shunt current back toward the input source, a controller for turning the switching elements on and off during each of a series of converter operating cycles and rectification elements which are arranged to deliver a unipolar current to the load.

Abstract: AC-DC boost switching power conversion apparatus delivers power from a bipolar input voltage source to a load at a unipolar load voltage without including rectifiers directly in the path of the current which is delivered from the input source. By this means the converter exhibits lower power loss in semiconductor diodes and switches than is exhibited by prior art converters which interpose a rectifier between a bipolar source and a DC-DC boost converter. Power processing is performed by circuitry of the kind which includes an inductive element in series with the bipolar input source, shunt paths which include switching elements for recirculating a bipolar shunt current back toward the input source, a controller for turning the switching elements on and off during each of a series of converter operating cycles and rectification elements which are arranged to deliver a unipolar current to the load.

Abstract: The automatic soldering of printed circuit boards wherein different boards can be simultaneously processed at different stations, e.g. a fluxing station, a preheating station and a soldering station. An identification station in advance of the fluxing station controls various parameters at the processing stations in response to board type as the boards are indexed through the various stations. Parameters such as location of application, time of application, pump speed etc. may be controlled in response to board type.

Abstract: Power is delivered from an input source to a load via a first capacitor in a series of energy transfer cycles, and a rate of change of voltage across the first capacitor is sensed as an indication of current flowing in the first capacitor.

Abstract: A transformer in which a magnetic medium provides flux paths within the medium, two or more windings enclose the flux paths at separated locations along the paths, and an electrically conductive medium, arranged in the vicinity of the magnetic medium and the windings, defines a boundary within which flux emanation from the magnetic medium and the windings is confined and suppressed. In a transformer constructed in accordance with the present invention, both controlled values of leakage inductance and the benefits of separated windings can be achieved. The conductive medium can be configured to reduce the leakage inductance of a controlled-leakage inductance transformer (e.g. for use in a zero-current switching power converter), having separately located windings, by at least 25%, and can be configured to reduce the leakage inductance of a low-leakage inductance transformer (e.g. for use in a PWM power converter), having separately located windings, by at least 75%.

Abstract: A package for electrical components in which a circuit board holds the components. The package includes an enclosure having generally parallel, spaced apart upper and lower internal surfaces. The circuit board lies generally parallel to the lower internal surface with the electrical components held in an internal-space between the circuit board and the upper internal surface. Conductive terminal pins extend from outside the enclosure into the internal space. The terminal pins are connected to the circuit board by conductive links, each link having an end attached to the periphery of the circuit board and another end projecting into the internal space.

Abstract: A closed-loop feedback system has first and second gain elements. The first gain element has a transfer function such that Xd=Kg * (Xcont).sup.z, where Xcont is a control variable input signal of the first gain element, Xd is a controlled variable output signal of the first gain element, and Kg and z are independent of Xcont. The second gain element has a transfer function h1 such that Xcont=h1(Xe) where Xe is a control variable input signal of the second gain element and Xcont is a controlled variable output signal of the second gain element. The function h1 is of a form which satisfies [1/h1(Xe)]*[.delta.h1(Xe)/.delta.Xe]=Ke, where Ke is independent of Xe.

Abstract: Electronic components are provided for connection in electronic circuits being manufactured on a production line. A supply of component blanks is provided, and each of the electronic components is formed by removing material from one of the blanks. The electronic component is delivered for connection in a corresponding one of the electronic circuits. The steps of forming and delivering the electronic component are coordinated with the manufacture of the corresponding electronic circuit. Another aspect features high-volume, high-mix manufacture of electronic circuits on a production line, where the mix requires a number M of different component values within a range of values R, and N (smaller than M) different supplies of component blanks are provided, each supply suitable for making components having values within a subrange S of range R. In another aspect, operating parameters of a laser are determined automatically for use in trimming resistor blanks belonging to a common batch of blanks.

Abstract: In a zero-current switching boost power converter which includes coupled inductors, and which operates in a half-cycle mode wherein the switch is turned off at the first zero-crossing of current subsequent to the switch being turned on, a negative voltage which would otherwise appear across the switch is instead supported by a saturable inductor. The component values in the zero-current switching boost converter are arranged so as to maintain the peak negative voltages which appear across the converter capacitor and the saturable inductor at relatively low levels and the volt-second capability of the saturable inductor is chosen so that the effect of the inductor on circuit losses and overall circuit operation is minimized. Implementations of switches for use in such a converter, which include a diode in parallel with a unidirectional switch, are also disclosed.

Abstract: A generally helical cut is made in a tubular conductive piece to form a winding, the winding having spaces between successive turns. The winding is axially compressed to reduce the spaces. One or more of the windings may be combined with one or more pieces of permeable or non-permeable material to form electromagnetic structures (for example, inductors or transformers) which have very high fill factors. A succession of such devices, each having possibly different numbers of turns on their windings, may be easily manufactured on a "lot-of-one" basis in an automated manufacturing environment.

Abstract: A boost switching preregulator includes a boost switching power conversion device which converts power from a source of essentially DC unipolar input voltage for delivery as an essentially DC unipolar output voltage to a load. The preregulator also includes a control device which accepts an input indicative of the magnitude of the output voltage and which, in response to variations in the magnitude of the input voltage, controls the boost switching power conversion device such that the magnitude of the output voltage varies within a range. Within this range, the unipolar output voltage is greater than or equal to the magnitude of the unipolar input voltage, and the span of the range is at least ten percent of the maximum value of the unipolar output voltage.

Abstract: A package for electrical components in which a circuit board holds the components. The package includes an enclosure having generally parallel, spaced apart upper and lower internal surfaces. The circuit board lies generally parallel to the lower internal surface with the electrical components held in an internal space between the circuit board and the upper internal surface. Conductive terminal pins extend from outside the enclosure into the internal space. The terminal pins are connected to the circuit board by conductive links, each link having an end attached to the periphery of the circuit board and another end projecting into the internal space.