Abstract: An electromagnetic apparatus includes: (a) A magnetic material arranged in a core structure establishing a first flux path set and a second flux path set; the first flux path set includes a first middle flux path oriented about a first axis and two first side flux paths parallel with the first axis; the second flux path set includes a second middle flux path oriented about a second axis and two second side flux paths parallel with the second axis; the second axis is perpendicular with the first axis. The first and second flux path sets cooperate to establish open spaces. Each open space is bounded by portions of two flux paths from each of the first and second flux path sets. (b) A plurality of windings for conducting electrical current about the magnetic core structure. The windings are oriented around one axis on both sides of the other axis.

Abstract: A modular power supply and a method of operating the same to accept either AC or DC input power. In one embodiment, the modular power supply includes an input module that accepts input power and employs at least one main power switch and a step-up transformer to provide intermediate power at an enhanced voltage at an output thereof. The modular power supply also includes a power transfer conductor coupled to the output. The modular power supply further includes an output module, having an input coupled to the conductor, that accepts the intermediate power and employs a step-down transformer and an output rectifier to provide DC output power at a voltage that is less than the enhanced voltage. The modular power supply still further includes a diode, coupled to the input and output modules, that prevents the step-up and step-down transformers from saturating.

Abstract: In accordance with the invention, a variety of magnetic devices can be made up of two or more low-profile surface components on a printed circuit board. For example, low profile devices comparable to gapped U-core pair and gapped E-core pair inductors or transformers can be formed of two and three components, respectively, and four components can be assembled into a gapped toroidal transformer or inductor. The components can be made in form for both linear and non-linear inductors.

Abstract: The present inventors have discovered that a compact, highly sensitive current sensor can be made for any inductive component having an air gap in its magnetic path by disposing a layer of magnetoresistive material in the path of the fringing magnetic field. In the preferred embodiment, a thin magnetoresistive film of La.sub.w Ca.sub.x Mn.sub.y O.sub.z on a LaAlO.sub.3 /Al.sub.2 O.sub.3 substrate provides a high sensitivity in the range of 1-100 mV/ampere of DC current in the inductive component. The current sensor consumes a very small amount of power and provides the desirable electrical isolation between the sensor and the active device circuit.

Abstract: A SEPIC converter powered off line is controlled to improve the input power factor by forcing the current in the input inductor to assume the same wave shape as the voltage across the inductor in series with the power switch to insure a sinewave input current. A switched capacitor is provided to provide brief holdover power to the converter should the input AC voltage fail.

Abstract: An arrangement for improving the power factor at the input of an off-line switching type power supply is operative to extend the duration of the pulse current conducted by the diode rectifiers. A parallel LC ringing circuit is introduced between the AC line and the rectifier of the switching type power supply to enhance the voltage enabling conduction of the rectifying diodes and hence initiate current flow through the rectifying diodes earlier in each half cycle. This extends the conduction interval of the rectifying diodes significantly and enhances the power factor at the input to the switching type power supply.

Abstract: A switching power amplifier circuit has the functions of a power inverter and a switching amplifier embodied into one integral circuit. Two high frequency switching inverter circuits are connected back to back sharing the same inverter power transformer. One switching inverter circuit processes power from an input rail to an output capacitor while the other switching inverter circuit processes power from the output capacitor to the input rail. The output capacitor voltage is regulated with respect to a signal input in order to obtain the desired output signal waveform. A blocking capacitor in the output absorbs the DC component of the output capacitor voltage and allows a pure AC ringing signal to be applied to the load. In an application as a ringing generator circuit the signal input is supplied by a ringing signal oscillator circuit.