For low-voltage and high-current applications, the secondary-side power losses have a major impact on efficiency. Typically, the current-doubler topology is widely adopted in high-current applications since it can offer lower conduction losses than the conventional center-tapped topology. To further reduce conduction loss for ultra-high current application, Current Tripler Rectification (CTR) is proposed by extending current-doubler concept to three phases (U.S Patent 6,944,033). With the help of integrated magnetics, current-tripler concept can be easily implemented. The proposed CTR has the following advantages: (a) Soft switching for primary switches; (b) Reduced synchronous rectifier conduction loss; (c) Reduced transformer winding loss; (d) Reduced transformer core loss; (e) Compact transformer structure, as compared with distributed magnetic; (f) Reduced output ripple current compared with current-doubler rectifiers.
A prototype is built to demonstrate the concept of the current-tripler dc/dc converter, which has a maximum efficiency of 87% at 1.0-V/100-A output, which is considerably better than the state-of-the-art practice.