DC-to-AC voltage converter having galvanically separate input and output circuits
First Claim
1. A DC-to-AC voltage converter having galvanically separate input and output circuits, and comprising a converter transformer having at least one primary winding;
- a resonance capacitor connected to said at least one primary winding;
a switching transistor having a collector-emitter path series-connected tot he at least one primary winding and a base-collector area; and
drive means for the switching transistor, wherein charge storage in the base-collector area of the switching transistor provides base drive for the switching transistor;
control means for detecting an increase of voltage in the collector-emitter path of the switching transistor and for providing in response to such an increase and at least in a period to time directly following the increase an additional base drive current for the switching transistor, which additional base drive current is gradually increased at a predetermined rate in such a manner that a storage time of the switching transistor remains substantially constant over an operating range of the converter.
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Accused Products
Abstract
A DC-to-AC voltage converter having galvanically separate onput and output circuits, and comprising a converter transformer having at least one primary winding; a resonance capacitor connected to said at least one primary winding; a switching transistor, of which the collector-emitter path is series-connected to the at least one primary winding; and drive means for the switching transistor, wherein charge storage in the base-collector area of the switching transistor provides base drive for the switching transistor, and further comprising control means for detecting an increase of the collector-emitter voltage (Uce) of the switching transistor and for providing in response to such an increase and at least in a period of time directly following the increase, an additional base drive current for the switching transistor, which additional base drive current is gradually increased at a predetermined rate in such a manner that the storage time of the switching transistor remains substantially constant over the operating range of the converter.
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Citations
12 Claims
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1. A DC-to-AC voltage converter having galvanically separate input and output circuits, and comprising a converter transformer having at least one primary winding;
- a resonance capacitor connected to said at least one primary winding;
a switching transistor having a collector-emitter path series-connected tot he at least one primary winding and a base-collector area; and
drive means for the switching transistor, wherein charge storage in the base-collector area of the switching transistor provides base drive for the switching transistor;
control means for detecting an increase of voltage in the collector-emitter path of the switching transistor and for providing in response to such an increase and at least in a period to time directly following the increase an additional base drive current for the switching transistor, which additional base drive current is gradually increased at a predetermined rate in such a manner that a storage time of the switching transistor remains substantially constant over an operating range of the converter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
- a resonance capacitor connected to said at least one primary winding;
Specification