Abstract: A half bridge power converter utilizes two oppositely phased power switches operated with unequal duty cycles. A magnetic arrangement with two inductance values having a ratio equal to the ratio of the unequal duty cycles is included in the converter to compensate for the unequal duty cycles.

Abstract: A DC-DC converter utilizes a tapped transformer secondary winding as a means of achieving output voltage ripple cancellation. This ripple cancellation occurs at a specified input voltage. It operates by fixing the location of a tap on the secondary winding of the power transformer so that the output voltage ripple cancellation occurs at the specified input voltage. It also minimizes the volt seconds that must be sustained by the output filter inductor over a specified range of input voltage for the converter.

Abstract: A drive arrangement and operative scheme for the power switching transistors of a half-bridge power drives the two power switching transistors with unequal duty cycles having conducting durations such that the sum of the conduction intervals substantially equals the combined switching period of the two power switching transistors. The conducting intervals are separated by very short dead time intervals controlled by the differing turn-on and turn-off times of the two power switching transistors. The short interval between alternate conductions of the two power switching transistors is sufficient to allow zero voltage turn on of the power switching transistors but short enough to minimize power loss and conducted noise.

Abstract: A converter operating in a resonant mode of operation is used as an off-line switching power supply operating with a high power density. A drive arrangement and operative scheme for driving the power switching transistors limits the dissipation losses within the power switching transistors. Drive circuitry drives two power switching transistors with unequal duty cycles having conducting durations such that the sum of the conduction intervals substantially equals the combined switching period of the two power switching transistors. These conducting intervals are separated by very short dead time intervals controlled by the differing turn-on and turn-off times of the two power switching transistors. The short interval between alternate conductions of the two power switching transistors is sufficient in duration to allow zero voltage turn on of the power switching transistors but short enough in duration to minimize power loss and conducted noise.

Abstract: A drive arrangement and operative scheme for the power switching transistors of a half-bridge power drives the two power switching transistors with unequal duty cycles having conducting durations such that the sum of the conduction intervals substantially equals the combined switching period of the two power switching transistors. The conducting intervals are separated by very short dead time intervals controlled by the differing turn-on and turn-off times of the two power switching transistors. The short interval between alternate conductions of the two power switching transistors is sufficient to allow zero voltage turn on of the power switching transistors but short enough to minimize power loss and conducted noise.Special biasing is provided to prevent drive signal application to power switches prior to attainment of a minimum voltage across the switch.Circuitry is provided for cancellation of output ripple currents at selected operating points of the power converter.

Abstract: Current sharing between paralleled power converters is attained by adjusting the error signal in the converters regulation circuit to assure that all the paralleled converters have a regulated output voltage that forces the converters to share the load equally. In particular circuitry is provided to limit the variation in output voltage that can be achieved through operation of the current sharing control.

Abstract: A single ended forward converter includes a snubber/reset circuit that diverts current flow from the power switching transistor during the turn off transition to significantly reduce switching loss therein. This same circuit is further operative to resonate energy stored in the magnetizing inductance of the power transformer with a capacitor during a nonconducting period of the power switching transistor in order to reverse the polarity of current, in the magnetizing inductor and reset the core, and further obtain bipolar flux excursions in the transformer core during each cycle of operation.