Research On Full-Bridge Current-Doubler Circuit Based On Synchronous Rectification

With the rapid development of information technology, small and medium-sized power converters have been widely used in computers, communication applications and other industry fields. In order to meet the demands of faster and more effective data processing in such fields, the demands of power supply of these equipments are also continuously increased. Lower output voltage, higher output current, higher efficiency, faster dynamic response and higher reliability is the trend of the development of power of supply.In this paper, the development history of switching power supply was firstly review , the present status and prospect of the low voltage and high current DC-DC converters were analyzed, Then the three typical rectifiers--Forward, Center-tapped and Current-doubler rectifiers have been compared. The result shows that, due to the low losses of rectifier tube, quick dynamic response and low ripples of output current, current-doubler rectifier is widely adopted in secondary topology of the main circuit.The full bridge with Current-doubler rectifier was adopted in the main circuit topology, and a new asymmetric PWM control strategy was employed in the driver. This control strategy is easy to implement and liable to achieve soft switching. The application of synchronous rectification technology in the main circuit makes it possible to achieve high efficent DC/DC converters.The working processes of full bridge circuit with current-doubler rectifier at every stage were particularly analyzed, and simulation study was carried out by PSPICE software in this paper. A prototype with 200W power output was designed to verify the valid of theory analysis and simulation results, and experimental researches in the two schemes of full bridge circuit with Current-doubler rectifier and full-bridge with Current-doubler rectifier basedon synchronous rectification were implemented. The results of experiment indicated the full bridge Current-doubler based on synchronous rectification was more suitable under low voltage and high current conditions.