Unregulated DC-DC converter having synchronous rectification with efficient gate drives

摘要

An unregulated DC-to-DC power converter suitable for intermediate bus voltage converter applications includes synchronous rectifiers that are driven efficiently to provide faster transition time and reduced loss. The DC-to-DC power converter comprises a transformer having a primary winding and at least first and second secondary windings. An input circuit is coupled to the primary winding and is adapted to apply an alternating polarity square wave voltage to the primary winding. An output circuit comprising an output filter is coupled to a tap of the first secondary winding. The output filter provides a DC output voltage. A first synchronous rectifier is coupled to a first end of the first secondary winding and a second synchronous rectifier is coupled to a second end of the first secondary winding. The second secondary winding has a first end coupled to a control terminal of the first synchronous rectifier and a second end coupled to a control terminal of the second synchronous rectifier. A first snubber circuit is coupled between the control terminal of the first synchronous rectifier and the second end of the first secondary winding. A second snubber circuit is coupled between the control terminal of the second synchronous rectifier and the first end of the first secondary winding. The first and second snubber circuits provide faster transition of the first and second synchronous rectifiers, respectively, between on and off states.