Organisation Europeenne De Recherches Spatiales

Other

Agence Spatiale Europeenne

Dermot M O'Sullivan

Alan H Weinberg

Jan Schreuders

A zero voltage switching DC/DC converter comprises a transformer with two opposed primary windings between which is a center tap and at least one secondary winding connected to a load by a rectifier and capacitor filter circuit. A first terminal of a constant voltage supply is connected to the center tap of the transformer. Two switching units are each connected in series between the second terminal of the voltage supply and a respective primary winding. The switches connect the second terminal of the voltage supply alternately and periodically to one or the other of the primary windings. A control device imposes between opening of one switch and subsequent closing of the other switch a switching time during which both switches are open. A device for automatically adjusting the switching time includes a detector adapted to compare the voltage of each primary winding with a reference voltage and an inhibiting device adapted to prevent, after opening of one switch, closing of the other switch until the voltage of the primary winding which corresponds to the latter switch falls below a predetermined threshold.

Zero voltage switching DC/DC converter

A controller apparatus comprising a phase-locked loop circuit which includes a phase comparator and a low-pass filter connected to accept a signal representing the switching frequency of the apparatus and an external frequency signal to produce a control signal for a controllable switch serving to vary the threshold levels of a reference signal, said control signal being a function of the phase difference between the input signals. The hysteresis of the apparatus is thereby changed over a few synchronization cycles in order to pull the controller into synchronization.

Apparatus for the control of a switched power regulator

A current sensing regulator operates in a switching mode of regulation between two sensed current levels in a free-running operation, or between one of the current levels and an intermediate level in a fixed-frequency synchronization operation. The sensed current levels at which switching occurs are set through a command signal, and a comparator controls switching at the set current levels or at the occurrence of synchronization pulses.

Current sensing regulator

A low dissipation shunt or series regulator apparatus is described comprising dump switching means coupled in parallel to each power source, which dump switching means is arranged for being responsive to a control signal produced by comparator means arranged for comparing the level of the error signal with a respective reference level. Each power source has its output connected to the reference level input of the corresponding comparator through feedback circuit means in order to set two operation thresholds for the comparator, thereby allowing each dump switching means to switch cyclically between two states, a first state serving to short the corresponding power source and a second state serving to allow the power source to provide current to the load.

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Leiderdorp, Netherlands

Dermot M O'Sullivan