Abstract: A new type of the passive non-dissipative snubber with a single saturable reactor improves the performance of the boost converter used as a front-end active Power Factor Correction (PFC) in two critical areas: excess voltage stresses caused by high voltage spikes on input high voltage switching transistor of the boost converter is eliminated and EMI noise is much reduced. The high voltage spike energy instead of being dissipated as in a dissipative snubber circuits is recovered resulting in increased conversion efficiency. High voltage spike elimination also allows use of lower voltage rated devices with lower ON resistance, hence further increasing the efficiency of the PFC boost converter.

Abstract: The Voltage Sense Method is introduced and a number of its implementations using Voltage Sense Circuit are demonstrated to solve problems associated with the start-up of parallel switching converters, each converter having output synchronous rectifiers or more general Current Bi-directional Switches: prevention of the excessive reverse current, elimination of the excess voltage stress of the input switches and elimination of the voltage overshoot in the common output voltage. The Voltage Sense circuit added to each converter generates a Simulated Output Voltage, which predicts how would the output voltage of each particular unit rise during the start-up with enabled synchronous rectifiers if that particular unit were to operate alone.

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.