Absorption circuit and push-pull circuit
By designing an absorption circuit including a one-way conduction module, capacitor and resistor in the push-pull circuit, the problem of excessive voltage stress when the switching device is turned off is solved, and lower heat loss and higher absorption effect are achieved.
Patent Information
- Application Number
- CN202420997950.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-09
- Publication Date
- 2025-03-14
- Estimated Expiration
- 2034-05-09
AI Technical Summary
In a circuit based on push-pull topology, when the switching device is turned off, the voltage stress generated by resonance leads to safety hazards and heating problems.
An absorption circuit is designed, including a first one-way conducting module, a first capacitor and a first resistor, absorbs resonant energy when it is turned on through the first one-way conducting module, and feeds part of the energy back into the push-pull circuit through the first resistor to reduce heat loss of the absorption circuit.
It effectively reduces the heat loss of the absorption circuit, improves the absorption effect and response speed, and ensures the protection effect of the switching devices.
Smart Images
Figure CN222621007U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of circuits, in particular to an absorption circuit and a push-pull circuit. Background Art
[0002] With the continuous development of power electronic circuits, the application scenarios of power electronic circuits are also constantly expanding. In the application scenarios of low input voltage and high input current, the commonly used power electronic circuit topology is the push-pull topology. This topology has the advantages of high efficiency and high power density. The mutual cooperation of switching devices and transformers can effectively realize voltage converters and inverters based on push-pull topology. Therefore, the application of push-pull topology is becoming more and more extensive, and users have higher and higher requirements for the reliability of circuits and devices based on push-pull topology.
[0003] However, during the operation of the circuit based on the push-pull topology, the parasitic capacitance of the switching device and the leakage inductance of the transformer will resonate when the switching device is turned off. The large amount of energy generated by the resonance will cause an excessive turn-off voltage at both ends of the switching device, resulting in excessive voltage stress when the switching device is turned off, causing the switching device to heat up, etc., posing a major safety hazard. How to deal with the situation where the voltage stress of the switching device is too large when it is turned off has become a technical problem that needs to be solved urgently. Utility Model Content
[0004] The purpose of the utility model is to provide an absorption circuit and a push-pull circuit, in which part of the resonant energy will be fed back to the push-pull circuit through the first resistor, thereby reducing the heat generated by the first capacitor and the first resistor in the absorption circuit during the process of absorbing the resonant energy, reducing the heat loss of the entire absorption circuit, improving the absorption effect and response speed of the entire absorption circuit, and ensuring the protection effect of the absorption circuit on the switching device.
[0005] In order to solve the above technical problems, the utility model provides an absorption circuit, which is applied to a push-pull circuit. The absorption circuit comprises:
[0006] A first unidirectional conducting module, the positive electrode of which is connected to the first end of the switch device in the push-pull circuit, and is used for conducting when the switch device is turned off;
[0007] A first capacitor, a first end of which is connected to the second end of the switch device;
[0008] A first resistor has a first end connected to the negative electrode of the first unidirectional conduction module and the second end of the first capacitor respectively, and a second end connected to the input end of the push-pull circuit.
[0009] Optionally, the absorption circuit further includes:
[0010] The second unidirectional conducting module has a positive electrode connected to the second end of the first resistor and a negative electrode connected to the input end of the push-pull circuit.
[0011] Optionally, the first unidirectional conducting module is a diode, the anode of the diode serves as the positive electrode of the first unidirectional conducting module, and the cathode of the diode serves as the negative electrode of the first unidirectional conducting module.
[0012] Optionally, the absorption circuit further includes:
[0013] A voltage stabilizing module, wherein a first end is respectively connected to the first end of the switch device and the positive electrode of the first unidirectional conducting module, and a second end is respectively connected to the second end of the switch device and the first end of the first capacitor, for clamping the voltage across the switch device.
[0014] Optionally, the voltage stabilizing module is a bidirectional transient voltage suppressor diode.
[0015] In order to solve the above technical problems, the utility model also provides a push-pull circuit, including a first switch tube, a second switch tube, a first absorption circuit and a second absorption circuit, wherein the first absorption circuit and the second absorption circuit are both the absorption circuits as described above, the first absorption circuit is connected in parallel with the first switch tube, and the second absorption circuit is connected in parallel with the second switch tube.
[0016] Optionally, the push-pull circuit further includes:
[0017] A transformer, a center tap of a primary winding serves as a first input end of the push-pull circuit, and is respectively connected to a second end of a first resistor of the first absorption circuit and a second end of a first resistor of the second absorption circuit, a secondary winding serves as an output end of the push-pull circuit, a first end of the primary winding is respectively connected to a first end of the first switching tube and a positive electrode of a first unidirectional conduction module of the first absorption circuit, a second end of the primary winding is respectively connected to a first end of the second switching tube and a positive electrode of a first unidirectional conduction module of the second absorption circuit, a second end of the second switching tube is respectively connected to a second end of the first switching tube, a first end of a first capacitor of the first absorption circuit and a first end of a first capacitor of the second absorption circuit, and serves as a second input end of the push-pull circuit.
[0018] Optionally, the push-pull circuit further includes:
[0019] a first inductor, a first end of which is connected to a first end of a secondary winding of the transformer;
[0020] A second capacitor has a first end connected to the second end of the first inductor, a second end serving as a first output end of the push-pull circuit, and a second end of the secondary winding of the transformer serving as a second output end of the push-pull circuit.
[0021] Optionally, the push-pull circuit further includes:
[0022] The third switch tube;
[0023] a fourth switch tube, a first end of which is respectively connected to the second end of the second capacitor and the first end of the third switch tube;
[0024] A third capacitor, a first end of which serves as a first output end of the push-pull circuit, and a second end of which serves as a second output end of the push-pull circuit;
[0025] a fifth switch tube, a first end of which is respectively connected to the second end of the third switch tube and the first end of the third capacitor;
[0026] A sixth switch tube, having a first end respectively connected to the second end of the secondary winding of the transformer and the second end of the fifth switch tube, and a second end respectively connected to the second end of the third switch tube and the second end of the third capacitor.
[0027] Optionally, the push-pull circuit further includes:
[0028] A fourth capacitor has a first end connected to the center tap of the primary winding of the transformer, and a second end connected to the second end of the first switch tube.
[0029] The utility model provides an absorption circuit, which is applied to a push-pull circuit. The absorption circuit includes a first unidirectional conduction module, a first capacitor and a first resistor. The positive electrode of the first unidirectional conduction module is connected to the first end of a switching device in the push-pull circuit. When the switching device is turned off, the resonant energy that causes the voltage stress of the switching device to increase is absorbed by the first capacitor through the first unidirectional conduction module that is turned on, and the first end of the first resistor is connected to the negative electrode of the first unidirectional conduction module. The first resistor provides a resonant energy dissipation path generated by the first capacitor when the switching device is turned off. At the same time, since the second end of the first resistor is connected to the input end of the push-pull circuit, part of the resonant energy will be fed back to the push-pull circuit through the first resistor, thereby reducing the heat generated by the first capacitor and the first resistor in the absorption circuit during the process of absorbing the resonant energy, reducing the heat loss of the entire absorption circuit, improving the absorption effect and response speed of the entire absorption circuit, and ensuring the protection effect of the absorption circuit on the switching device.
[0030] The utility model provides a push-pull circuit, which has the same beneficial effects as the above-mentioned absorption circuit. BRIEF DESCRIPTION OF THE DRAWINGS
[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the prior art and the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.
[0032] Figure 1 A schematic diagram of the structure of an absorption circuit provided by the utility model;
[0033] Figure 2 A schematic diagram of the structure of another absorption circuit provided by the utility model;
[0034] Figure 3 The present invention provides a schematic diagram of the structure of a push-pull circuit. DETAILED DESCRIPTION
[0035] The core of the utility model is to provide an absorption circuit and a push-pull circuit. Part of the resonant energy will be fed back to the push-pull circuit through the first resistor, thereby reducing the heat generated by the first capacitor and the first resistor in the absorption circuit during the absorption of the resonant energy, reducing the heat loss of the entire absorption circuit, improving the absorption effect and response speed of the entire absorption circuit, and ensuring the protection effect of the absorption circuit on the switching device.
[0036] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.
[0037] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of an absorption circuit provided by the utility model; please refer to Figure 2 , Figure 2 A schematic diagram of another absorption circuit provided by the utility model; To solve the above technical problems, the utility model provides an absorption circuit 2, which is applied to the push-pull circuit 1, and the absorption circuit 2 includes:
[0038] A first unidirectional conducting module D1, whose positive electrode is connected to a first end of a switch device Q0 in a push-pull circuit 1, and is used for conducting when the switch device Q0 is turned off;
[0039] A first capacitor C1, a first end of which is connected to a second end of the switch device Q0;
[0040] The first resistor R1 has a first end connected to the negative electrode of the first unidirectional conducting module D1 and the second end of the first capacitor C1 respectively, and a second end connected to the input end of the push-pull circuit 1 .
[0041] Specifically, the switch device Q0 in the push-pull circuit 1 is directly connected to the transformer T. When the switch device Q0 is turned off, the parasitic parameters of the switch device Q0 and the parasitic parameters of the transformer T will resonate. Generally, the parasitic parameters of the switch device Q0 that produce resonance mainly refer to the parasitic capacitance of the switch device Q0, and the parasitic parameters of the transformer T mainly refer to the leakage inductance of the transformer T. The generated resonance will cause the voltage stress of the switch device Q0 to increase. At this time, the first unidirectional conduction module D1 in the absorption circuit 2 will be in a conducting state due to the large voltage across the two ends of the switch device Q0. The resonant energy is absorbed by the first capacitor C1 in the absorption circuit 2 through the turned-on first unidirectional conduction module D1. At the same time, part of the resonant energy is fed back to the power input end of the push-pull circuit 1 through the first resistor R1 to reduce the situation where the resonant energy all acts on the absorption circuit 2 when the switch device Q0 is turned off. The fed-back resonant energy no longer needs to be absorbed by the absorption circuit 2, thereby avoiding excessive heat generated by the absorption circuit 2 and improving the absorption effect of the absorption circuit 2. When the switch device Q0 is turned off, the voltage across its two ends will be greater than the input voltage of the push-pull circuit. At this time, the first unidirectional conduction module D1 needs to be turned on to absorb the resonant energy, and the voltage across the first capacitor C1 rises during its conduction process. Then, when the positive electrode voltage of the first unidirectional conduction module D1 is less than the negative electrode voltage, the first unidirectional conduction module D1 is turned off.
[0042] It is not difficult to understand that the absorption circuit 2 is connected in parallel to the resonant circuit where the switch device Q0 is located as a buffer. When the switch device Q0 is turned off, the first unidirectional conduction module D1 will be turned on, and the first capacitor C1 provides a path for absorbing the resonant energy. The first resistor R1 can provide a damping channel for the resonant energy, which facilitates the resonant energy to be fed back to the input end of the push-pull circuit 1. Therefore, the capacity of the first capacitor C1 will affect the absorption degree of the resonant energy. A capacitor with a suitable capacity can be selected according to the resonant frequency of the resonant network in actual applications to achieve a better absorption effect. At the same time, the resistance value of the first resistor R1 will also affect the magnitude of the resonant energy fed back. Therefore, the resonant energy absorption effect of the entire absorption circuit 2 can be adjusted by adjusting the resistance value of the first resistor R1. The specific values of the capacitance of the first capacitor C1 and the resistance value of the first resistor R1 can be determined according to the specific situation of the push-pull circuit 1 in the actual application process. According to the parasitic parameters of the switch device Q0 and the resonance characteristics of the parasitic parameters of the transformer T in the topology of the push-pull circuit 1 during the period when the switch device Q0 is turned off, the first capacitor C1 and the first resistor R1 in the absorption circuit 2 are analyzed and calculated to select appropriate hardware parameters.
[0043] It should be noted that the first unidirectional conduction module D1 can be implemented by a semiconductor diode. When the switch device Q0 is turned on, the voltage difference between the two ends of the switch device Q0 is very small, and the diode is in a cut-off state. When the switch device Q0 is turned off, due to the generation of resonance, there is a large voltage difference between the two ends of the switch device Q0. After exceeding the conduction voltage of the diode, the diode is turned on and introduces the resonant energy into the absorption circuit 2; the specific types and implementation methods of the first unidirectional conduction module D1, the first capacitor C1 and the first resistor R1 are not particularly limited in this application. In addition to the diode, the first unidirectional conduction module D1 can also be implemented by other unidirectional conduction devices such as thyristors; the first capacitor C1 can be implemented by a non-polar capacitor, and the first resistor R1 can be implemented by a simple fixed resistor. The specific implementation methods such as the setting method and setting position of the absorption circuit 2 in the push-pull circuit 1 are not particularly limited in this application. In terms of circuit layout, the absorption circuit 2 can be set close to the switch device Q0 to achieve a better absorption effect.
[0044] It is not difficult to understand that the absorption circuit 2 provided in the present application is a solution for absorbing the voltage stress of the switch tube in the resonant push-pull circuit. The RCD composite resistor-capacitor series absorber composed of the first unidirectional conduction module D1, the first resistor R1 and the first capacitor C1 is used. While absorbing the resonant energy of the switch device Q0 turning off, part of the resonant energy is fed back to the input side of the circuit. The entire absorption circuit 2 is simple in structure and low in implementation cost. The device parameters in the absorption circuit 2 are easy to determine, and part of the resonant energy is fed back to the push-pull circuit 1 itself, reducing the resonant energy absorbed by the absorption circuit 2 itself, so that each device in the absorption circuit 2 has the characteristics of low power, small temperature rise and low absorption loss when absorbing the resonant energy. In particular, when the push-pull circuit 1 is applied to the converter, the absorption circuit 2 used in the present application can effectively improve the overall efficiency and power density of the converter, so that the push-pull circuit 1 can provide more switch device Q0 selections, and achieve a good absorption effect.
[0045] The push-pull circuit 1 of the utility model has good absorption effect for both steady-state working conditions and dynamic working conditions. Compared with the general RC absorber, the composite RCD absorber adopted by the utility model can release part of the pressure of the first capacitor C1 and the first resistor R1, greatly reducing the heat loss of the entire absorption circuit 2, and the device temperature rise is only about one-fifth of the general parallel RC absorber. It has better absorption effect on the voltage stress of the switching device Q0, faster response speed, stronger protection ability for the switching device Q0, and improves the problems of high loss, large device, poor effect, and difficult layout of the RC absorber. Part of the resonant energy is fed back to the power input side, so the selection parameters of the first capacitor C1 and the first resistor R1 can be reduced, the selectivity is stronger, the application range is wider, and under the same working conditions, the cost of using the absorption circuit 2 of the utility model is reduced, the cost performance is high, and the absorption performance is more excellent.
[0046] The absorption circuit 2 provided by the utility model can be used in fields such as power electronics, and is applicable to any switching device Q0 that may generate resonance, especially to a resonant topology circuit with low input voltage and high input current, and is used to absorb the voltage stress when the low-voltage side switching device in the resonant circuit is turned off.
[0047] The utility model provides an absorption circuit 2, which is applied to a push-pull circuit 1. The absorption circuit 2 includes a first unidirectional conduction module D1, a first capacitor C1 and a first resistor R1. The positive electrode of the first unidirectional conduction module D1 is connected to the first end of the switch device Q0 in the push-pull circuit 1. When the switch device Q0 is turned off, the resonant energy that causes the voltage stress of the switch device Q0 to increase is absorbed by the first capacitor C1 through the first unidirectional conduction module D1 that is turned on, and the first end of the first resistor R1 is connected to the negative electrode of the first unidirectional conduction module D1. The first resistor R1 also absorbs the resonant energy. At the same time, since the second end of the first resistor R1 is connected to the input end of the push-pull circuit 1, part of the resonant energy will be fed back to the push-pull circuit 1 through the first resistor R1, thereby reducing the heat generated by the first capacitor C1 and the first resistor R1 in the absorption circuit 2 during the process of absorbing the resonant energy, reducing the heat loss of the entire absorption circuit 2, improving the absorption effect and response speed of the entire absorption circuit 2, and ensuring the protection effect of the absorption circuit 2 on the switch device Q0.
[0048] Based on the above embodiments:
[0049] As an optional embodiment, the absorption circuit 2 further includes:
[0050] The second unidirectional conducting module has a positive electrode connected to the second end of the first resistor R1 , and a negative electrode connected to the input end of the push-pull circuit 1 .
[0051] Considering that the resonant energy fed back to the input end of the push-pull circuit 1 through the first resistor R1 needs to be effectively input into the push-pull circuit 1, in order to avoid abnormal situations such as energy reversal in the process of feeding back the resonant energy, a second unidirectional conduction module can be further provided between the second end of the first resistor R1 and the input end of the push-pull circuit 1 to specify the energy flow direction in the process of feeding back the resonant energy, avoid heat loss of the absorption circuit 2 caused by energy reversal, and ensure the absorption effect of the entire absorption circuit 2. The specific type and implementation method of the second unidirectional conduction module are not particularly limited in this application, and can be implemented by diodes or thyristors.
[0052] Specifically, a second unidirectional conduction module can be further added to specify the direction of energy flow in the process of feedback resonant energy, ensure the correct direction of the feedback resonant energy, avoid excessive heat loss of the absorption circuit 2, improve the reliability and safety of the entire absorption circuit 2, and ensure the absorption effect of the entire absorption circuit 2.
[0053] As an optional embodiment, the first unidirectional conducting module D1 is a diode, the anode of the diode serves as the positive electrode of the first unidirectional conducting module D1 , and the cathode of the diode serves as the negative electrode of the first unidirectional conducting module D1 .
[0054] It is not difficult to understand that the first unidirectional conduction module D1 can be implemented by a diode, and the unidirectional conduction characteristics of the diode are used to realize the process of conducting the resonant energy. The diode will be in a cut-off state when the switching device Q0 is turned on, thereby avoiding the influence of the absorption circuit 2 on the normal conduction process of the switching device Q0 in the push-pull circuit 1. The specific type and implementation method of the diode are not particularly limited in this application.
[0055] Specifically, a diode can be used to effectively implement the function of the first unidirectional conduction module D1. The diode has low cost, small size, easy implementation, and simple structure, which is conducive to the simple implementation of the absorption circuit 2 and the entire push-pull circuit 1, and avoids the absorption circuit 2 causing cost and volume burdens on the push-pull circuit 1.
[0056] As an optional embodiment, the absorption circuit 2 further includes:
[0057] The voltage stabilizing module D0 has a first end connected to the first end of the switch device Q0 and the positive electrode of the first unidirectional conducting module D1, and a second end connected to the second end of the switch device Q0 and the first end of the first capacitor C1, for clamping the voltage across the switch device Q0.
[0058] It is not difficult to understand that, considering that the push-pull circuit 1 may have a sudden load causing a sudden change in the primary current, a parallel voltage stabilizing module D0 may be further added to the absorption circuit 2. The voltage stabilizing module D0 is mainly used to deal with the power mutation in the push-pull circuit 1. The duty cycle of the driving signal of the switching device Q0 will gradually increase, and the resonant energy generated will be parabolic, showing a state of first increasing and then decreasing. Under this dynamic condition, compared with the changing resonant energy, the absorption speed of the first capacitor C1 and the first resistor R1 to the resonant energy is relatively slow. At this time, in order to improve the absorption effect, the voltage stabilizing module D0 can be used to quickly clamp the voltage stress at both ends of the switching device Q0, thereby enhancing the response speed of the first capacitor C1 and the first resistor R1 in the absorption circuit 2 to the absorption of the voltage stress of the switching device Q0 caused by the power mutation, and providing a reverse path for the large resonant energy in this process. The specific type and implementation method of the voltage stabilizing module D0 are not particularly limited in this application, and can be implemented by a bidirectional voltage stabilizing diode or the like. Furthermore, after the parameters of the first capacitor C1 and the first resistor R1 are adjusted and matched, the voltage stabilizing module D0 with appropriate parameters can be selected through a power mutation test.
[0059] Specifically, after adding the voltage stabilizing module D0, the protection characteristics of the entire absorption circuit 2 can take into account the full range coverage of the steady-state and dynamic conditions of the push-pull circuit 1. When the push-pull topology operates in a steady-state condition, the absorption circuit 2 directly uses the first capacitor C1 and the first resistor R1 to achieve effective absorption of the resonant energy; when there is a dynamic change in power in the push-pull topology, the voltage stabilizing module D0 can be used to quickly clamp the voltage stress of the switching device Q0, thereby improving the absorption effect of the first capacitor C1 and the first resistor R1; under different operating conditions of the push-pull circuit 1, effective absorption of the resonant energy can be guaranteed, ensuring the absorption effect of the entire absorption circuit 2.
[0060] As an optional embodiment, the voltage stabilizing module D0 is a bidirectional transient voltage suppressor diode.
[0061] It is not difficult to understand that, considering that the voltage regulator module D0 needs to complete the voltage stress clamping process of the switching device Q0 in time before the absorption circuit 2 starts to absorb the resonant energy, the voltage regulator module D0 needs to have a faster response speed than the diode. Considering factors such as cost, the voltage regulator module D0 can be realized by using a bidirectional transient suppression diode. The bidirectional TVS tube (Transient Voltage Suppression Diode) Suppressors (transient suppression diodes) can effectively block the freewheeling path of the absorption circuit 2 under steady-state conditions and work directly under dynamic conditions. When the operating frequency of the switching device Q0 is high and the driving duty cycle of the switching device Q0 is gradually opened, the resonant energy shows a parabolic growth in the entire dynamic condition. The conduction time of the diode is difficult to match the operating frequency of the switching device Q0, and the voltage stress absorption effect is not good. Therefore, in the dynamic condition, the voltage stress of the switching device Q0 will be clamped by a bidirectional transient suppression diode first to prevent the diode from directly responding to the dynamic condition. After the voltage stress of the switching device Q0 is clamped by the bidirectional transient suppression diode, the diode, the first capacitor C1 and the first resistor R1 will begin to absorb the resonant energy to ensure the absorption effect of the absorption circuit 2. Due to the advantage of fast switching action response speed, the bidirectional transient suppression diode will give priority to the voltage stress change of the switching device. The diode, the first capacitor C1 and the first resistor R1 will start to work after the diode is turned on.
[0062] Specifically, in dynamic conditions, a bidirectional transient suppression diode is used to clamp the voltage stress of the switching device Q0, thereby avoiding the influence on the absorption effect caused by the difficulty of the diode in matching the operating frequency of the switching device Q0 under dynamic conditions, and effectively improving the absorption of the resonant energy in the push-pull circuit 1 under dynamic conditions by the entire absorption circuit 2; the entire circuit structure is simple and easy to implement, which is conducive to the simple implementation of the absorption circuit 2 and the entire push-pull circuit 1.
[0063] As a specific embodiment, Figure 2 As shown, the composite RCD absorber provided by the utility model is composed of four parts: a voltage mutation suppression diode as a voltage stabilizing module D0, a loop selection diode as a first unidirectional conduction module D1, a frequency selection capacitor as a first capacitor C1, and a linear resistor as a first resistor R1. The entire absorption circuit 2 is directly connected in parallel to both ends of the power stage of the switching device Q0, and the absorption output pin Power_in+ is connected to the power input positive electrode of the push-pull circuit 1. When applied, the placement position of the absorption circuit 2 should be as close as possible to the two poles of the switch tube to achieve a better absorption effect.
[0064] Please refer to Figure 3 , Figure 3A schematic diagram of a push-pull circuit provided by the utility model. To solve the above technical problems, the utility model also provides a push-pull circuit 1, comprising a first switch tube Q1, a second switch tube Q2, a first absorption circuit and a second absorption circuit, wherein the first absorption circuit and the second absorption circuit are both the absorption circuit 2 as described above, the first absorption circuit is connected in parallel with the first switch tube Q1, and the second absorption circuit is connected in parallel with the second switch tube Q2.
[0065] It is not difficult to understand that the absorption circuit 2 is used in parallel with the switch device Q0 when it is used. When there are multiple switch devices Q0 in the push-pull circuit 1, an absorption circuit 2 can be connected in parallel to both ends of the multiple switch devices Q0, or some of the switch devices Q0 can be selected to be connected in parallel with the absorption circuit 2 according to the specific resonance conditions of the switch devices Q0 in actual applications. In this embodiment, an absorption circuit 2 is connected in parallel to both ends of the first switch tube Q1 and the second switch tube Q2 in the push-pull circuit 1; the specific number and location of the absorption circuit 2 in the push-pull circuit 1 can be selected and set according to the actual working process of the push-pull circuit 1, and this application does not make any special restrictions here.
[0066] For an introduction to a push-pull circuit provided by the present invention, please refer to the above-mentioned embodiment of the absorption circuit, and the present invention will not be described in detail here.
[0067] As an optional embodiment, the push-pull circuit 1 further includes:
[0068] The center tap of the primary winding of the transformer T serves as the first input end of the push-pull circuit 1, and is respectively connected to the second end of the first resistor R1 of the first absorption circuit and the second end of the first resistor R1 of the second absorption circuit; the secondary winding serves as the output end of the push-pull circuit 1; the first end of the primary winding is respectively connected to the first end of the first switch tube Q1 and the positive electrode of the first unidirectional conduction module D1 of the first absorption circuit; the second end of the primary winding is respectively connected to the first end of the second switch tube Q2 and the positive electrode of the first unidirectional conduction module D1 of the second absorption circuit; the second end of the second switch tube Q2 is respectively connected to the second end of the first switch tube Q1, the first end of the first capacitor C1 of the first absorption circuit and the first end of the first capacitor C1 of the second absorption circuit, and serves as the second input end of the push-pull circuit 1.
[0069] It is understandable that in the push-pull circuit 1, two switch tubes are set on the low-voltage side of the transformer T to realize the switch device Q0 of the push-pull structure. The first switch tube Q1 and the second switch tube Q2 are alternately turned on and mutually connected with the transformer T to realize a push-pull converter. At this time, the parasitic capacitance of the first switch tube Q1 and the parasitic capacitance of the second switch tube Q2 are both connected to the transformer T, and resonance may exist. Therefore, it is necessary to set a first absorption circuit in parallel at both ends of the first switch tube Q1, and a second absorption circuit in parallel at both ends of the second switch tube Q2. The specific types and implementation methods of the transformer T, the first switch tube Q1 and the second switch tube Q2 in the push-pull circuit 1 are not particularly limited in this application.
[0070] Specifically, the first switch tube Q1, the second switch tube Q2 and the transformer T are connected to each other, which can effectively realize a push-pull converter. The conversion process of the AC power supply can be effectively realized by utilizing the voltage boost of the transformer T and the alternating conduction process of the first switch tube Q1 and the second switch tube Q2. The entire circuit structure is simple and easy to implement.
[0071] As an optional embodiment, the push-pull circuit 1 further includes:
[0072] A first inductor Lr, a first end of which is connected to a first end of a secondary winding of the transformer T;
[0073] The second capacitor C2 has a first end connected to the second end of the first inductor Lr, and a second end serving as a first output end of the push-pull circuit 1 . The second end of the secondary winding of the transformer T serves as a second output end of the push-pull circuit 1 .
[0074] It is not difficult to understand that, considering that there may be interference signals in the alternating current directly output by the transformer T, a first inductor Lr and a second capacitor C2 connected in series may be added at the output end of the secondary winding of the transformer T. The first inductor Lr and the second capacitor C2 form a series LC circuit, and the signal of a specific frequency can be selected for amplification or suppression by adjusting the inductance value of the first inductor Lr and the capacitance value of the second capacitor C2, thereby filtering or separating the alternating current output by the transformer T. The specific type and implementation method of the first inductor Lr and the second capacitor C2 are not particularly limited in this application.
[0075] Specifically, the frequency selectivity and filtering characteristics of the series LC circuit can effectively realize the filtering and separation process of the output AC power, improve the accuracy and reliability of the output current of the push-pull circuit 1, and the entire circuit structure is simple and easy to implement, which is conducive to the simple implementation of the entire push-pull circuit 1.
[0076] As an optional embodiment, the push-pull circuit 1 further includes:
[0077] The third switch tube Q3;
[0078] A fourth switch tube Q4, a first end of which is respectively connected to the second end of the second capacitor C2 and the first end of the third switch tube Q3;
[0079] A third capacitor C3, a first end of which serves as a first output end of the push-pull circuit 1, and a second end of which serves as a second output end of the push-pull circuit 1;
[0080] A fifth switch tube Q5, a first end of which is respectively connected to the second end of the third switch tube Q3 and the first end of the third capacitor C3;
[0081] The sixth switch tube Q6 has a first end respectively connected to the second end of the secondary winding of the transformer T and the second end of the fifth switch tube Q5 , and a second end respectively connected to the second end of the third switch tube Q3 and the second end of the third capacitor C3 .
[0082] It is not difficult to understand that the push-pull circuit 1 can not only realize the output of alternating current, but also further add a rectifier circuit composed of a third switch tube Q3, a fourth switch tube Q4, a fifth switch tube Q5 and a sixth switch tube Q6 on the output side of the transformer T to rectify the alternating current output by the transformer T, thereby realizing the output of direct current. Therefore, the push-pull circuit 1 can realize different types of power converters, and can further be provided with a third capacitor C3 connected in parallel at both ends of the rectifier circuit to realize filtering, thereby improving the stability and accuracy of the final output direct current. The specific types and implementation methods of the third switch tube Q3, the fourth switch tube Q4, the third capacitor C3, the fifth switch tube Q5 and the sixth switch tube Q6 are not particularly limited in this application.
[0083] Specifically, a DC power converter can be further realized based on the push-pull circuit 1 by adding structures such as a rectifier circuit. The entire push-pull circuit 1 can be applied to different types of power converters, has strong flexibility, and improves the application scope of the absorption circuit 2 and the entire push-pull circuit 1.
[0084] As an optional embodiment, the push-pull circuit 1 further includes:
[0085] The fourth capacitor C4 has a first end connected to the center tap of the primary winding of the transformer T, and a second end connected to the second end of the first switch tube Q1.
[0086] It is not difficult to understand that, considering that the power supply connected to the input end of the push-pull circuit 1 may have interference such as voltage fluctuations, a fourth capacitor C4 connected in parallel may be further provided on the input side of the push-pull circuit 1 to perform preliminary filtering on the connected power supply, thereby improving the accuracy and reliability of the subsequent entire push-pull circuit 1.
[0087] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.
[0088] It should also be noted that, in this specification, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.
[0089] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. An absorption circuit, characterized in that: Applied to a push-pull circuit, the absorption circuit comprises: A first unidirectional conducting module, the positive electrode of which is connected to the first end of the switch device in the push-pull circuit, and is used for conducting when the switch device is turned off; A first capacitor, a first end of which is connected to the second end of the switch device; A first resistor has a first end connected to the negative electrode of the first unidirectional conduction module and the second end of the first capacitor respectively, and a second end connected to the input end of the push-pull circuit.
2. The absorption circuit according to claim 1, characterized in that: The absorption circuit also includes: The second unidirectional conducting module has a positive electrode connected to the second end of the first resistor and a negative electrode connected to the input end of the push-pull circuit.
3. The absorption circuit according to claim 1, characterized in that: The first unidirectional conducting module is a diode, the anode of the diode serves as the positive electrode of the first unidirectional conducting module, and the cathode of the diode serves as the negative electrode of the first unidirectional conducting module.
4. The absorption circuit according to any one of claims 1 to 3, characterized in that: The absorption circuit also includes: A voltage stabilizing module, wherein a first end is respectively connected to the first end of the switch device and the positive electrode of the first unidirectional conducting module, and a second end is respectively connected to the second end of the switch device and the first end of the first capacitor, for clamping the voltage across the switch device.
5. The absorption circuit according to claim 4, characterized in that: The voltage stabilizing module is a bidirectional transient suppression diode.
6. A push-pull circuit, characterized in that: It includes a first switching tube, a second switching tube, a first absorption circuit and a second absorption circuit, wherein the first absorption circuit and the second absorption circuit are both the absorption circuits according to any one of claims 1 to 5, the first absorption circuit is connected in parallel with the first switching tube, and the second absorption circuit is connected in parallel with the second switching tube.
7. The push-pull circuit according to claim 6, characterized in that: The push-pull circuit also includes: A transformer, a center tap of a primary winding serves as a first input end of the push-pull circuit, and is respectively connected to a second end of a first resistor of the first absorption circuit and a second end of a first resistor of the second absorption circuit, a secondary winding serves as an output end of the push-pull circuit, a first end of the primary winding is respectively connected to a first end of the first switching tube and a positive electrode of a first unidirectional conduction module of the first absorption circuit, a second end of the primary winding is respectively connected to a first end of the second switching tube and a positive electrode of a first unidirectional conduction module of the second absorption circuit, a second end of the second switching tube is respectively connected to a second end of the first switching tube, a first end of a first capacitor of the first absorption circuit and a first end of a first capacitor of the second absorption circuit, and serves as a second input end of the push-pull circuit.
8. The push-pull circuit according to claim 7, characterized in that: The push-pull circuit also includes: a first inductor, a first end of which is connected to a first end of a secondary winding of the transformer; A second capacitor has a first end connected to the second end of the first inductor, a second end serving as a first output end of the push-pull circuit, and a second end of the secondary winding of the transformer serving as a second output end of the push-pull circuit.
9. The push-pull circuit according to claim 8, characterized in that: The push-pull circuit also includes: The third switch tube; a fourth switch tube, a first end of which is respectively connected to the second end of the second capacitor and the first end of the third switch tube; A third capacitor, a first end of which serves as a first output end of the push-pull circuit, and a second end of which serves as a second output end of the push-pull circuit; a fifth switch tube, a first end of which is respectively connected to the second end of the third switch tube and the first end of the third capacitor; A sixth switch tube, having a first end respectively connected to the second end of the secondary winding of the transformer and the second end of the fifth switch tube, and a second end respectively connected to the second end of the third switch tube and the second end of the third capacitor.
10. The push-pull circuit according to claim 9, characterized in that: The push-pull circuit also includes: A fourth capacitor has a first end connected to the center tap of the primary winding of the transformer, and a second end connected to the second end of the first switch tube.