Flyback double voltage rectifier circuit and high voltage output switching power supply

Abstract

The application discloses a flyback double-voltage rectifier circuit, and belongs to the technical field of flyback conversion and rectification of high-voltage output switching power supply. The circuit comprises a transformer, a first energy storage capacitor, a second energy storage capacitor, a third energy storage capacitor, a first rectifier diode, a second rectifier diode and a third rectifier diode. The secondary winding of the transformer is connected with the three energy storage capacitors and the three rectifier diodes to form a charging and voltage superposition network. The output positive end is arranged at the cathode side of the third rectifier diode, and the output negative end is arranged at the same name end side of the secondary winding. The circuit charges the energy storage capacitors by using the switching period of the transformer, and superposes the voltages of the energy storage capacitors according to the polarity, so that the double DC voltage output is realized, thereby reducing the required output voltage of the secondary side and the voltage resistance requirement of the rectifier element, and reducing the volume of the transformer. The application further discloses a high-voltage output switching power supply comprising the flyback double-voltage rectifier circuit.

Description

Technical Field

[0001] This invention relates to the field of switching power supply technology, and in particular to a flyback double voltage multiplier rectifier circuit and a high-voltage output switching power supply. Background Technology

[0002] Switching power supplies provide the required output voltage to a load through power electronic conversion. In high-voltage output applications, as the required output voltage increases, the number of turns in the transformer's secondary high-voltage winding typically needs to be increased accordingly. Increasing the number of turns in the secondary winding increases the transformer's size and height, and raises the voltage withstand requirements of related components in the rectifier circuit. Therefore, the transformer size and the voltage withstand capability of rectifier components under high-voltage output conditions are issues that need to be considered in switching power supply design.

[0003] Existing technologies have solutions for improving the secondary-side rectification of high-output-voltage flyback converters. For example, the solution disclosed in patent application CN119543669A connects two secondary windings in series and sets a center tap on the secondary side. Synchronous rectifiers are set on both the high-side and low-side of the secondary side. Simultaneously, the middle connection point of two voltage-equalizing capacitors is connected to the center tap on the secondary side, and a voltage-equalizing resistor is set in parallel with the voltage-equalizing capacitors. This solution distributes the reverse voltage borne by the rectifiers through the joint operation of the high-side and low-side synchronous rectifiers. This type of solution requires a segmented secondary winding and center-tapped structure, and the configuration of synchronous rectifier devices and voltage-equalizing networks.

[0004] Existing technologies also include high-voltage output switching power supply solutions that employ voltage doubler rectifier circuits. For example, the solution disclosed in patent application CN106972742A utilizes capacitors and diodes to construct a voltage doubler rectifier circuit, and sets up a π-type differential-mode filter and an LC common-mode filter after the rectifier circuit to suppress differential-mode ripple noise and common-mode ripple noise in the output. This type of solution mainly focuses on circuit configuration related to rectification and ripple noise suppression under high-voltage output conditions.

[0005] For high-voltage output flyback circuits, the number of turns in the transformer secondary winding, transformer size, and the withstand voltage requirements of rectifier components remain interrelated design constraints. Existing technologies employ segmented secondary windings and synchronous rectification structures, or voltage doubler rectification and multi-stage filtering structures, to achieve the corresponding design goals.

[0006] Therefore, how to achieve DC voltage multiplication in a high-voltage output flyback circuit with a relatively simple secondary-side rectifier structure, while reducing the required output voltage of the transformer secondary side and the withstand voltage requirements of the rectifier components, has become an urgent technical problem to be solved. Summary of the Invention

[0007] The main objective of this invention is to provide a flyback voltage doubler rectifier circuit and a high-voltage output switching power supply. The aim is to achieve DC voltage multiplication in a high-voltage output flyback circuit with a relatively simple secondary-side rectifier structure, while reducing the required output voltage of the transformer secondary side and the withstand voltage requirements of the rectifier components.

[0008] To achieve the above objectives, the present invention proposes a flyback voltage doubler rectifier circuit, comprising a transformer, a first energy storage capacitor, a second energy storage capacitor, a third energy storage capacitor, a first rectifier diode, a second rectifier diode, and a third rectifier diode; The transformer has a secondary winding, which has terminals with the same name and terminals with different names. One end of the first energy storage capacitor is connected to the cathode of the first rectifier diode, and the other end of the first energy storage capacitor is connected to the same-name end of the secondary winding. The anode of the first rectifier diode is connected to the opposite terminal of the secondary winding; One end of the second energy storage capacitor is connected to the cathode of the second rectifier diode, and the other end of the second energy storage capacitor is connected to the anode of the first rectifier diode; The cathode of the second rectifier diode is connected to the anode of the third rectifier diode; One end of the third energy storage capacitor is connected to the anode of the second rectifier diode, and the other end of the third energy storage capacitor is connected to the cathode of the third rectifier diode. The connection point between the cathode of the third rectifier diode and the other end of the third energy storage capacitor constitutes the positive output terminal of the flyback voltage doubler rectifier circuit, and the connection point between the corresponding terminal of the secondary winding and the other end of the first energy storage capacitor constitutes the negative output terminal of the flyback voltage doubler rectifier circuit.

[0009] Preferably, the transformer further comprises a primary winding, and the flyback doubler rectifier circuit is configured as follows: When the primary side of the transformer is in the off-state, the first rectifier diode is turned on to charge the first energy storage capacitor. When the primary side of the transformer is in the conduction stage again, the first rectifier diode is turned off and the second rectifier diode is turned on to charge the second energy storage capacitor. When the primary side of the transformer is in the off-state again, the second rectifier diode is turned off and the third rectifier diode is turned on to charge the third energy storage capacitor.

[0010] Preferably, after charging through multiple switching cycles, the first energy storage capacitor, the second energy storage capacitor, and the third energy storage capacitor reach a steady state, and the output voltage between the positive output terminal and the negative output terminal is formed by adding the voltages across the first energy storage capacitor and the third energy storage capacitor in polarity.

[0011] Preferably, ignoring the forward voltage drops of the first rectifier diode, the second rectifier diode, and the third rectifier diode, the output voltage of the positive output terminal relative to the negative output terminal is... The voltage of the opposite terminal of the secondary winding relative to the negative output terminal when the primary side of the transformer is in the off-state phase. satisfy: .

[0012] This application also discloses a high-voltage output switching power supply, including the aforementioned flyback voltage doubler rectifier circuit. The high-voltage output switching power supply referred to herein is a switching power supply that includes the aforementioned flyback voltage doubler rectifier circuit and utilizes the aforementioned flyback voltage doubler rectifier circuit to achieve voltage doubler output.

[0013] Preferably, the high-voltage output switching power supply adopts a single-ended flyback topology.

[0014] The above technical solution has the following advantages: Compared to solutions employing segmented secondary windings, center taps, synchronous rectifiers, and voltage equalization networks, this application utilizes the connection relationship between the transformer secondary winding, three energy storage capacitors, and three rectifier diodes to form a flyback voltage doubler rectifier network. Compared to solutions that add a π-type differential-mode filter and an LC common-mode filter after the voltage doubler rectifier circuit, this application's technical solution achieves voltage multiplication through the flyback voltage doubler rectifier network. The three rectifier diodes rectify and guide the current, enabling the secondary winding to charge the corresponding energy storage capacitors during the switching cycle. After the energy storage capacitors reach a steady state, the voltages of the first and third energy storage capacitors can be superimposed according to polarity to form the output voltage, thereby achieving a double DC voltage output. Under the same output voltage requirement, the required output voltage of the transformer secondary winding can be reduced, thereby reducing the number of turns in the secondary winding and the transformer size. Simultaneously, the withstand voltage requirements of the rectifier circuit components can be reduced. Attached Figure Description

[0015] The present invention will now be described in detail with reference to specific embodiments and accompanying drawings, wherein: Figure 1 The circuit diagram of the flyback voltage doubler rectifier circuit provided in the embodiments of this application is shown. Detailed Implementation

[0016] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0017] like Figure 1 As shown in the figure, this application embodiment provides a high-voltage output switching power supply. This high-voltage output switching power supply adopts a single-ended flyback topology. The high-voltage output switching power supply includes a flyback voltage doubler rectifier circuit. This flyback voltage doubler rectifier circuit can achieve twice the DC voltage output. When designing the transformer, the output voltage of the secondary transformer can be reduced to half of the original output voltage, reducing the voltage withstand requirements of the rectifier circuit components and decreasing the transformer size, which is beneficial for the lightweight and miniaturized design of the power supply.

[0018] The flyback doubler rectifier circuit includes a transformer T1, a first energy storage capacitor C1, a second energy storage capacitor C2, a third energy storage capacitor C3, a first rectifier diode D1, a second rectifier diode D2, and a third rectifier diode D3. The transformer T1 has a primary winding and a secondary winding. The secondary winding has terminals with the same name and terminals with different names.

[0019] One end of the first energy storage capacitor C1 is connected to the cathode of the first rectifier diode D1. The other end of the first energy storage capacitor C1 is connected to the same-name terminal of the secondary winding. The anode of the first rectifier diode D1 is connected to the opposite-name terminal of the secondary winding. One end of the second energy storage capacitor C2 is connected to the cathode of the second rectifier diode D2. The other end of the second energy storage capacitor C2 is connected to the anode of the first rectifier diode D1. The cathode of the second rectifier diode D2 is connected to the anode of the third rectifier diode D3. One end of the third energy storage capacitor C3 is connected to the anode of the second rectifier diode D2. The other end of the third energy storage capacitor C3 is connected to the cathode of the third rectifier diode D3. Figure 1 In the diagram, A represents the node connecting the opposite terminal of the secondary winding, the anode of the first rectifier diode D1, and the other end of the second energy storage capacitor C2; B represents the node connecting one end of the first energy storage capacitor C1, the cathode of the first rectifier diode D1, the anode of the second rectifier diode D2, and one end of the third energy storage capacitor C3; D represents the node connecting one end of the second energy storage capacitor C2, the cathode of the second rectifier diode D2, and the anode of the third rectifier diode D3; VO+ represents the positive output terminal; GND represents the negative output terminal.

[0020] The flyback doubler rectifier circuit utilizes the rectification and guiding effects of diodes to continuously charge the energy storage capacitor through the secondary winding, storing the voltage across the capacitor. The voltages across the capacitors are then added together according to their polarities, thus achieving a DC voltage output of twice the normal value. The specific working process is as follows.

[0021] When the primary side of transformer T1 is in the conducting phase, the primary input is the voltage relative to the primary input ground. At this point, a coupled negative voltage is generated at the opposite terminal of the secondary winding relative to the negative terminal of the output.

[0022] When the primary winding of transformer T1 is in the off-state, the first rectifier diode D1 is turned on, and the circuit charges the first energy storage capacitor C1. At this time, the potential at the opposite terminal of the secondary winding becomes high.

[0023] When the primary side of transformer T1 is in the conducting stage again, the first rectifier diode D1 is cut off, the second rectifier diode D2 is turned on, and the circuit charges the second energy storage capacitor C2.

[0024] When the primary side of transformer T1 is turned off again, the second rectifier diode D2 is cut off, the third rectifier diode D3 is turned on, and the circuit charges the third energy storage capacitor C3.

[0025] After charging through multiple switching cycles, the first energy storage capacitor C1, the second energy storage capacitor C2, and the third energy storage capacitor C3 reach a steady state. The output voltage between the positive and negative output terminals is formed by adding the voltages across the first energy storage capacitor C1 and the third energy storage capacitor C3 in polarity order. Ignoring the forward voltage drops of the first rectifier diode D1, the second rectifier diode D2, and the third rectifier diode D3, the output voltage between the positive and negative output terminals is... The voltage relative to the negative output terminal of the opposite terminal of the secondary winding when the primary side of transformer T1 is in the off-state phase. satisfy: .

[0026] The aforementioned high-voltage output switching power supply can be widely used in various equipment requiring high-voltage power. Specifically, in military and civilian electronic systems such as aerospace, aviation, shipbuilding, weaponry, railway, communications, medical electronics, or industrial automation equipment, this high-voltage output switching power supply can provide a stable voltage to ensure the normal operation of the system. By adopting the aforementioned flyback voltage doubler rectifier circuit, this power supply effectively controls the size of the transformer and the overall device while meeting the high-voltage output requirements, conforming to the current development trend of lightweight and miniaturized electronic equipment.

[0027] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit of the invention should fall within the protection scope of the present invention.

Claims

1. A flyback voltage doubler rectifier circuit, characterized in that, It includes a transformer, a first energy storage capacitor, a second energy storage capacitor, a third energy storage capacitor, a first rectifier diode, a second rectifier diode, and a third rectifier diode; The transformer has a secondary winding, which has terminals with the same name and terminals with different names. The same-named end of the secondary winding is connected to the other end of the first energy storage capacitor, and the connection point of the two constitutes the output negative terminal of the flyback voltage doubler rectifier circuit. The opposite end of the secondary winding, the anode of the first rectifier diode, and the other end of the second energy storage capacitor are connected to the same node; One end of the first energy storage capacitor is connected to the cathode of the first rectifier diode; One end of the second energy storage capacitor, the cathode of the second rectifier diode, and the anode of the third rectifier diode are connected to the same node; The anode of the second rectifier diode is connected to one end of the third energy storage capacitor; The other end of the third energy storage capacitor is connected to the cathode of the third rectifier diode, and the connection point of the two constitutes the positive output terminal of the flyback voltage doubler rectifier circuit.

2. The flyback voltage doubler rectifier circuit according to claim 1, characterized in that, The transformer also has a primary winding, and the flyback doubler rectifier circuit is configured as follows: When the primary side of the transformer is in the off-state, the first rectifier diode is turned on to charge the first energy storage capacitor. When the primary side of the transformer is in the conducting phase again, the first rectifier diode is turned off and the second rectifier diode is turned on to charge the second energy storage capacitor. When the primary side of the transformer is in the off-state again, the second rectifier diode is turned off and the third rectifier diode is turned on to charge the third energy storage capacitor.

3. The flyback voltage doubler rectifier circuit according to claim 2, characterized in that, After charging through multiple switching cycles, the first energy storage capacitor, the second energy storage capacitor, and the third energy storage capacitor reach a steady state. The output voltage between the positive output terminal and the negative output terminal is formed by adding the voltages across the first energy storage capacitor and the third energy storage capacitor in terms of polarity.

4. The flyback voltage doubler rectifier circuit according to claim 3, characterized in that, Ignoring the forward voltage drops of the first rectifier diode, the second rectifier diode, and the third rectifier diode, the output voltage of the positive output terminal relative to the negative output terminal is... The voltage of the opposite terminal of the secondary winding relative to the negative output terminal when the primary side of the transformer is in the off-state phase. satisfy: 。 5. A high-voltage output switching power supply, characterized in that, Includes the flyback doubler rectifier circuit according to any one of claims 1 to 4.

6. The high-voltage output switching power supply according to claim 5, characterized in that, The high-voltage output switching power supply adopts a single-ended flyback topology.

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