Abstract: A non-isolated and isolated both polarity non-inverting and polarity inverting switching DC-to-DC converters with three switches are provided with a basic voltage step-up DC gain characteristics and a very efficient operation without a danger of voltage overstress of any of the three switches over the full operating range from duty ratio of 0 to 1.0, thus resulting in wide input voltage operating range. The isolated extensions feature transformer with no DC-bias for efficient operation and small size. Full-bridge secondary side implementation further reduces the output filtering requirements.

Abstract: Switching Converter with a novel two-loop Integrated magnetic structure integrates transformer and two output inductors and eliminates large circulating current in the transformer secondary side resulting in ultra high efficiency and zero ripple output current as well as zero ripple currents in both output inductors simultaneously. The novel lossless switching method eliminates the primary side switching losses to result in switching converter with highest efficiency, compact size and additional performance advantages, such as ultra low output ripple voltage, low EMI noise and improved reliability with additional benefits when operated with a front-end Power Factor Converter for computer server applications.

Abstract: A new lossless switching DC-to-DC converter with novel lossless switching time control for up to four controllable switches, with each switch meeting the specific current-voltage switching characteristics, operates at ultra high efficiency in a very compact size and offers additional performance advantages, such as low EMI noise, low switching ripple currents, and improved reliability.

Abstract: Soft switching DC-to-DC converter operates at record high efficiency despite its small size and weight and ultra high overload current capability of several times the nominal load current. Such performance is made possible by use of unique magnetic and switching circuits with special properties. Other desirable performance features are provided concurrently such as: zero ripple current on input and output, low conducted and radiated Electromagnetic interference (EMI) noise, as well as low component stresses for increased converter reliability.

Abstract: A new switching converter operates at record high efficiency despite its small size and light weight and enables ultra high overload current capability owing to two novel methods: new Lossless Switching method eliminates switching losses by use of a precise sequence and timing of the four controllable switches, while novel DC Transformer structure provides a method to eliminate the stored DC energy in magnetics, which further increases efficiency and reduces the magnetics and converter size.

Abstract: Soft switching DC-to-DC converter achieves simultaneously ultra high efficiency and very small size owing to a new magnetic circuit structure and a corresponding novel converter circuit configuration with special properties. Unique magnetic design also provides an overload current capability of several times the nominal load current. Despite its simple implementation requiring only proper drive timing of the switching devices, the unique soft-switching methods result in nearly complete elimination of switching losses over the entire operating range. This, in turn, permits operation at even higher switching frequencies, and leads to further reduction in size and weight.

Abstract: Soft switching DC-to-DC converter operates at record high efficiency despite its small size and weight and ultra high overload current capability of several times the nominal load current. Such performance is made possible by use of unique magnetic and switching circuits with special properties. Other desirable performance features are provided concurrently such as: zero ripple current on input and output, low conducted and radiated Electromagnetic interference (EMI) noise, as well as low component stresses for increased converter reliability.

Abstract: A single-switch ac-to-ac converters for driving ac loads which are particularly suitable for gas discharge lamp ballast applications based upon integration of automatic current shapers and converters that resemble a class-E converter, both parts sharing a single active switch. The first part comprises a high power factor (HPF) converter having automatic input current-shaping means and internal energy storage means operated by the single active switch driven at a constant frequency and duty ratio, and the second part comprises a resonant converter means operated by the aforesaid single active switch as it is being driven. Integration of the HPF converter having automatic current shaping means and the resonant converter through the single active switch operation brings advantages from both parts into the whole circuit, such as soft-switching characteristics so that the combined circuit can shape the input current without switching losses in a compact structure.

Abstract: A discontinuous conduction mode (DCM) electronic ballast topology is presented which drives the lamp with line frequency voltage and current, just like a magnetic ballast. However, compared to magnetic ballast, its weight is substantially reduced due to operation at high switching frequency (40 kHz in the experimental prototype). The topology also ensures unity power factor at the input and stable lamp operation at the output.

Abstract: The isolated, multiple output, switching converter is created with a number of unique performance characteristics. The converter operates in continuous inductor current mode (CICM) of operation for all load currents from no load to full load on all outputs despite the presence of simple rectifier diodes only on the converter secondary sides. The regulation of output voltages on all outputs against the changes of the input voltage is provided by use of a simple open-loop control circuit connected to the primary side and thus eliminating the need for isolation in the control circuit. The regulation against the load current changes in the single output case is also provided on the primary side by a load current sensing circuit. An additional benefit of the switching converter is in the elimination of the losses and voltage overshoots associated with the leakage inductance of the isolation transformer when operated as pulse width modulated (PWM) converter.

Abstract: In a dc-to-dc converter, input and output inductors loosely coupled and isolation transformer windings closely coupled are implemented on a UI magnetic core in such a manner as to satisfy a zero-ripple condition k.sub.1 =n of current in the output inductor, where n is a turns ratio of the loosely coupled input and output inductors, and both inductors are chosen to have the same number of turns, and that number is an integer such that the value of the coupling coefficient k.sub.1 required to satisfy the zero-ripple condition is one achieved by modeling of core leakages instead of by adjusting the turns ratio n, thus making it feasible to implement the coupled inductors, and the transformer windings as well, in a single UI core and modeling the core losses by configuring the core.

Abstract: An ac-to-dc switching full-bridge converter employing voltage bidirectional switches as controllable series input switches, preferably implemented with magnetic amplifiers, that couple ac rectifiers to a single-stage full-bridge dc-to-dc converter in order to provide unity power factor operation by control of input current using a fast current loop to modulate the duty ratio d1 of the voltage bidirectional amplifier switches while independent output voltage regulation is maintained by voltage feedback to the full-bridge converter switches through modulation of the switch duty ratio d of the converter (where d1<d) using an independent fast output regulation loop.

Abstract: Ac-to-dc switching converters employ bidirectional voltage switches, preferably magnetic amplifiers in series with a fast recovery diode, as controllable series input switches that couple ac rectifiers to single-stage dc-to-dc converters in order to provide unity power factor operation by control of current through the input inductor achieved by modulating the duty ratio d1 of the bidirectional voltage switch while independent regulation of load voltage is maintained by voltage feedback to modulate the switch duty ratio d of the converter (where d1<d) in an independent fast output regulation loop.

Abstract: An isolated switching dc-to-dc converter is provided with a novel open-loop input voltage regulation on the primary side and the full regulation and independent protection of each of multiple outputs on the secondary side using an auxiliary circuit comprising a current bidirectional switch Q.sub.a and a capacitor C.sub.a on the primary side in a series circuit connected in parallel with a main current bidirectional switch Q to assure a continuous conduction mode for operation of the primary boost-like converter, and consequently preserves the simplicity of open-loop input voltage regulation for all loads from no load to full load. The auxiliary switch Q.sub.a is very efficient with only a fraction (5% or less) of the losses of the main active switch Q. The ideal dynamic response approaching theoretical limits is achieved for both line and load transients together with a high efficiency (85%) and record power density (20 W per cubic inch) for multiple output converters.

Abstract: A soft-switching dc-to-dc converter for providing regulated voltage to a load combines the functions of loss-less soft switching at zero voltage and at a constant switching frequency on the primary side and soft switching at zero current on the secondary side of an isolation transformer for all load currents from full load to no-load and PWM output voltage regulation on the secondary side. This is made possible by using voltage bidirectional switching element in series with a low-pass filter on the secondary side and current bidirectional switching element on the primary side driven at close to 50% duty ratio with adjustable dead time between switching. The adjustable dead-time is realized by sensing voltages across paired primary side current bidirectional switching element in order to enable alternate turn ON of said pair only at zero voltage, thereby eliminating or greatly reducing switching losses under all load current conditions.

Abstract: A novel isolated, capacitive idling, Cuk switching-mode converter features two separate nonisolated feedback loops, one on the primary side to regulate against input voltage changes and the other on the secondary side to regulate against load current changes only. While preserving cost, size and simplicity of conventional multiple output switching-mode converters, the new converter and feedback control approach offers the advantages of simple feedback control implementation due to elimination of isolation requirements in the feedback control circuits, simultaneous regulation of all output voltages from no load to full load, and greatly improved bandwidth and step-load transient response. For operation from a rectified ac line, feedback control on the input to the transformer is modified to force the average input current to follow the full-wave rectified ac line voltage for unity power factor (UPF) performance on the input and wide bandwidth voltage regulation on the output.

Abstract: A DC voltage to a load is provided from a rectified AC power line source with unity power factor using Cuk dc-to-dc switching converter, either unisolated or isolated extensions, operated as an automatic current shaper with unity power factor performance. This is obtained by operating the Cuk converter in a discontinuous inductor current mode (DICM) at a constant switching frequency and constant duty ratio without input current feedback control customarily used, but operating in an open-loop fashion. Even though the Cuk converter is operated in DICM, its input current is nonpulsating and flowing throughout the switching cycle, unlike other converters having pulsating input current in DICM, thus reducing input harmonic currents due to switching frequency and its harmonics.

Abstract: A gas discharge lamp ballast provides near unity power factor simultaneously with high-frequency lamp ballasting in a single switching power conversion stage resulting in efficiency improvements, reduction in size and weight and reduced component count and cost. The single conversion stage comprises a fast-recovery diode connecting in series the input inductor, energy transfer capacitor and the resonant matching network, and switching means alternately connecting the first junction between the input inductor and energy transfer capacitor, or the second junction between the matching network and the other side of said capacitor to the return current path. The switching means comprises two current bidirectional switches driven out of phase, thus producing a square-wave high frequency voltage source, which is in turn converted by the resonant matching network into a sine-wave ac current source required by the gas discharge lamp.