Biphasic dickson switched capacitor converters with zero voltage switching

Abstract

A biphasic Dickson switched capacitor converter with zero voltage switching is provided. The biphasic Dickson switched capacitor converter introduces an auxiliary circuit between middle points of two freewheeling bridge arms of a conventional biphasic Dickson converter, and charges at a middle point of a first freewheeling bridge arm are transferred to a second freewheeling bridge arm by controlling the auxiliary circuit during a dead time when main power transistors are turned off to realize zero voltage switching of the main power transistors and reduce a switching loss. An on-resistance of an introduced auxiliary power transistor is larger than an on-resistance of the main power transistors. An inductance value of an auxiliary inductor is small and a package size and cost are low. Therefore, the biphasic Dickson switched capacitor converter reduces the switching loss of switched capacitor converter, improve efficiency, have performance benefits and commercial prospects by introducing the auxiliary circuit.

What is claimed is: 
     
         1 . A biphasic Dickson switched capacitor converter with zero voltage switching, wherein two freewheeling bridge arms comprising a first freewheeling bridge arm and a second freewheeling bridge arm are provided on two sides of an output end of a topology structure of the biphasic Dickson switched capacitor converter, and a power transistor in the biphasic Dickson switched capacitor converter is defined as a main power transistor, wherein a control auxiliary circuit is provided between the two freewheeling bridge arms, and the control auxiliary circuit is used for transferring charges on the first freewheeling bridge arm to the second freewheeling bridge arm during a dead time when main power transistors are turned off, wherein voltages at two ends of the main power transistors become zero to achieve zero voltage switching of the main power transistors. 
     
     
         2 . The biphasic Dickson switched capacitor converter according to  claim 1 , wherein the biphasic Dickson switched capacitor converter is a biphasic 4:1 switched capacitor converter with zero voltage switching, comprising a first power transistor, a second power transistor, a third power transistor, a fourth power transistor, a fifth power transistor, a sixth power transistor, a seventh power transistor, an eighth power transistor, a ninth power transistor, a tenth power transistor, an eleventh power transistor, a twelfth power transistor, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor and a sixth capacitor;
 wherein a first end of the eighth power transistor is connected to an external input voltage, a second end of the eighth power transistor is connected to a first end of the seventh power transistor and a first end of the third capacitor, a first end of the twelfth power transistor is connected to the external input voltage, and a second end of the twelfth power transistor is connected to a first end of the eleventh power transistor and a first end of the sixth capacitor;   a second end of the seventh power transistor is connected to a first end of the sixth power transistor and a first end of the fifth capacitor, and a second end of the eleventh power transistor is connected to a first end of the tenth power transistor and a first end of the second capacitor;   a second end of the sixth power transistor is connected to a first end of the fifth power transistor and a first end of the first capacitor, and a second end of the tenth power transistor is connected to a first end of the ninth power transistor and a first end of the fourth capacitor;   a second end of the fifth power transistor is connected to a first end of the second power transistor, and a second end of the ninth power transistor is connected to a first end of the third power transistor;   a second end of the second power transistor is connected to a first end of the first power transistor, a second end of the first capacitor, a second end of the second capacitor and a second end of the third capacitor;   a second end of the third power transistor is connected to a first end of the fourth power transistor, a second end of the fourth capacitor, a second end of the fifth capacitor and a second end of the sixth capacitor;   a connection point of the fifth power transistor, the second power transistor, the third power transistor and the ninth power transistor is an output end;   the two freewheeling bridge arms are respectively defined as the first freewheeling bridge arm and the second freewheeling bridge arm, and a connection point of the first power transistor, the second power transistor, the first capacitor, the second capacitor and the third capacitor is a middle point of the first freewheeling bridge arm, and a connection point of the third power transistor, the fourth power transistor, the fourth capacitor, the fifth capacitor and the sixth capacitor is a middle point of the second freewheeling bridge arm;   the control auxiliary circuit comprises a thirteenth power transistor, a fourteenth power transistor, a fifteenth power transistor, a sixteenth power transistor and an inductor;   wherein a first end of the thirteenth power transistor is connected to the middle point of the first freewheeling bridge arm, a second end of the thirteenth power transistor is connected to a first end of the inductor and a first end of the fourteenth power transistor, and a second end of the fourteenth power transistor is grounded;   a second end of the inductor is connected to a first end of the fifteenth power transistor and a first end of the sixteenth power transistor, a second end of the fifteenth power transistor is grounded, and a second end of the sixteenth power transistor is connected to the middle point of the second freewheeling bridge arm.   
     
     
         3 . The biphasic Dickson switched capacitor converter according to  claim 2 , wherein a working sequence of the biphasic 4:1 switched capacitor converter with zero voltage switching comprises four stages as follows:
 a first stage: the second power transistor, the fourth power transistor, the sixth power transistor, the eighth power transistor, the ninth power transistor, the eleventh power transistor, the fourteenth power transistor and the sixteenth power transistor are turned on, and remaining power transistors are turned off; the first capacitor, the third capacitor and the fifth capacitor are enabled to be in a charge state, the second capacitor, the fourth capacitor and the sixth capacitor are in a discharge state, and an inductive current is 0 in the first stage;   a second stage: the thirteenth power transistor and the sixteenth power transistor are turned on, and remaining power transistors are turned off; the inductive current firstly increases and then decreases in the second stage, and the second stage ends when the inductive current decreases to 0;   a third stage: the first power transistor, the third power transistor, the fifth power transistor, the seventh power transistor, the tenth power transistor, the twelfth power transistor, the thirteenth power transistor and the fifteenth power transistor are turned on, and remaining power transistors are turned off; the first capacitor, the third capacitor and the fifth capacitor are enabled to be in the discharge state, the second capacitor, the fourth capacitor and the sixth capacitor are in the charge state, and the inductive current is 0 in the third stage;   a fourth stage: the thirteenth power transistor and the sixteenth power transistor are turned on, and remaining power transistors are turned off; the inductive current first increases and then decreases in the fourth stage, and the fourth stage ends when the inductive current decreases to 0, and the first stage is returned.