A flyback power supply circuit and switching power supply
Patent Information
- Application Number
- CN202522350646.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-05
- Publication Date
- 2026-09-29
- Estimated Expiration
- 2035-11-05
AI Technical Summary
[0004]本申请的主要目的在于提供一种反激式电源电路及开关电源，旨在解决相关技术中多反激拓扑存在电路结构复杂，导致空间占用大且成本高的技术问题
提出了一种反激式电源电路，包括多个变压器、检测反馈模块、控制模块和开关驱动模块，其中的变压器包括一个原边绕组和若干个副边绕组，该电路还包括各变压器中与原边绕组并联的一原边支路以及与若干个副边绕组对应连接的若干个副边支路，可以形成多副边支路的多反激拓扑的拓扑结构；针对该拓扑结构，将多个变压器对应的多个原边支路的一端并接，并作为该反激式电源电路的正输入端，可以根据需要拓展副边支路的数量，适应更多场景需要；多个原边支路的另一端均与开关驱动模块的第一端连接，开关驱动模块的第二端则作为该反激式电源电路的负输入端，并以若干个副边支路中任意一个副边支路为反馈支路，多个变压器对应的多个反馈支路均与检测反馈模块连接，检测反馈模块与控制模块连接，控制模块与开关驱动模块的控制端连接，即使是多反激拓扑，也只需要配置一个控制模块和一个开关驱动模块，简化了电路结构，减小空间占用面积，从而可以减小电路PCB板面积和降低成本；而且，本申请还可以在确保电路多输出均可正常工作的情况下，实现精度较高的输出电压可调控制。
Smart Images
Figure CN224818048U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of switching power supply technology, and in particular to a flyback power supply circuit and a switching power supply. Background Technology
[0002] Flyback topologies are widely used in switching power supplies, commonly found in single-secondary-side and multi-secondary-side topologies. In both of these topologies, the primary side is typically a single primary-side branch. In switching power supply scenarios using multiple flyback topologies, especially when each flyback has multiple secondary-side branches, a separate primary-side control circuit needs to be designed for each primary-side branch. This primary-side control circuit includes at least one controller and one switching transistor, thus requiring multiple controllers and multiple switching transistors, matching the number of flyback topologies.
[0003] Therefore, current multi-flyback topology switching power supplies suffer from problems such as complex circuit structure, large space occupation, and high cost. Utility Model Content
[0004] The main purpose of this application is to provide a flyback power supply circuit and a switching power supply, which aims to solve the technical problems of complex circuit structure, large space occupation and high cost in the multi-flyback topology of related technologies.
[0005] To achieve the above objectives, this application proposes a flyback power supply circuit, including multiple transformers, a detection feedback module, a control module, and a switch drive module. The transformers include a primary winding and several secondary windings. For each transformer, the primary winding is connected in parallel to a primary branch, and several secondary windings are connected to several secondary branches. Any one of the several secondary branches is a feedback branch. One end of each primary branch corresponding to multiple transformers is connected in parallel and serves as the positive input terminal of the flyback power supply circuit. The other end of each primary branch is connected to the first terminal of the switch drive module. The second terminal of the switch drive module serves as the negative input terminal of the flyback power supply circuit. Each feedback branch corresponding to multiple transformers is connected to the detection feedback module. The detection feedback module is connected to the control module. The control module is connected to the control terminal of the switch drive module.
[0006] In one embodiment, the plurality of transformers includes m transformers, where m ≥ 2 and m is a positive integer; the plurality of primary side branches includes m primary side branches; the plurality of secondary side windings includes n secondary side windings, where n is a positive integer; the plurality of secondary side branches includes n secondary side branches; the m transformers correspond to m × n secondary side branches; and the plurality of feedback branches includes m feedback branches.
[0007] In one embodiment, the detection feedback module is used to detect the output voltage of each feedback branch to obtain m output voltages; The control module is used to perform a weighted average of m output voltages to obtain a feedback voltage; adjust the output voltage of each of the m feedback branches according to the feedback voltage to obtain the corresponding m first adjustment voltages; and, for each transformer, calculate the adjustment voltage of each of the remaining secondary branches according to the first adjustment voltage and the turns ratio of the secondary winding corresponding to the feedback branch to the secondary winding corresponding to the other secondary branches to obtain n-1 second adjustment voltages, so as to obtain m×(n-1) second adjustment voltages corresponding to the m transformers; and generate a pulse modulation signal according to the m first adjustment voltages and m×(n-1) second adjustment voltages to dynamically adjust the on / off state of the switch drive module to realize the adjustment of the output voltage of the m×n secondary branches.
[0008] In one embodiment, the detection feedback module includes m detection resistors and a voltage divider resistor; One end of each of the m sensing resistors is connected to the positive output terminal of each of the m feedback branches, and the other end of each of the m sensing resistors is connected to the feedback terminal of the control module and one end of the voltage divider resistor, respectively. The other end of the voltage divider resistor is grounded.
[0009] In one embodiment, the switch driving module includes a switching transistor; The drain of the switching transistor serves as the first terminal of the switching drive module and is connected to the other end of each of the m primary branches. The source of the switching transistor serves as the second terminal of the switching drive module, and the gate of the switching transistor serves as the control terminal of the switching drive module and is connected to the drive terminal of the control module.
[0010] In one embodiment, the switch driving module further includes a drain-source capacitor; One end of the drain-source capacitor is connected to the drain of the switching transistor, and the other end of the drain-source capacitor is connected to the source of the switching transistor.
[0011] In one embodiment, each primary branch includes a first resistor, a first capacitor, and a first diode; One end of the first resistor and one end of the first capacitor are connected in parallel and serve as one end of the primary branch. The other ends of the first resistor and the first capacitor are respectively connected to the negative terminal of the first diode, and the positive terminal of the first diode serves as the other end of the primary branch.
[0012] In one embodiment, each secondary branch includes a second diode, a second capacitor, and a second resistor; The positive terminal of the second diode serves as the first terminal of the secondary branch, which is connected to one end of the corresponding secondary winding. The negative terminal of the second diode is connected to one end of the second capacitor and one end of the second resistor, serving as the second terminal of the secondary branch and the positive output terminal of the flyback power supply circuit. The other end of the second capacitor and the other end of the second resistor are connected in parallel, serving as the third terminal of the secondary branch. The third terminal of the secondary branch is connected to the other end of the corresponding secondary winding and also serves as the negative output terminal of the flyback power supply circuit.
[0013] In one embodiment, a bus capacitor is also included; One end of the bus capacitor is connected to the positive input terminal of the flyback power supply circuit, and the other end of the bus capacitor is connected to the negative input terminal of the flyback power supply circuit.
[0014] To achieve the above objectives, this application also proposes a switching power supply, including the flyback power supply circuit described above.
[0015] One or more technical solutions proposed in this application have at least the following technical effects: A flyback power supply circuit is proposed, comprising multiple transformers, a detection feedback module, a control module, and a switch drive module. Each transformer includes a primary winding and several secondary windings. The circuit also includes a primary branch connected in parallel with the primary winding of each transformer and several secondary branches corresponding to the secondary windings, forming a multi-flyback topology with multiple secondary branches. For this topology, one end of each of the multiple primary branches corresponding to the multiple transformers is connected in parallel and serves as the positive input terminal of the flyback power supply circuit. The number of secondary branches can be expanded as needed to adapt to more application scenarios. The other ends of each of the multiple primary branches are connected to the first... The second terminal of the switch driver module serves as the negative input terminal of the flyback power supply circuit, and any one of the secondary branches is used as the feedback branch. Multiple feedback branches corresponding to multiple transformers are connected to the detection feedback module, which is connected to the control module. The control module is connected to the control terminal of the switch driver module. Even with a multi-flyback topology, only one control module and one switch driver module are required, simplifying the circuit structure, reducing the space occupied, thereby reducing the PCB board area and lowering the cost. Moreover, this application can achieve high-precision adjustable output voltage control while ensuring that all multiple outputs of the circuit can work normally. Attached Figure Description
[0016] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.
[0017] To more clearly illustrate the technical solutions in the embodiments or related technologies of this application, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.
[0018] Figure 1 This is a schematic diagram of the structure of an embodiment of the flyback power supply circuit of this application; Figure 2 This is a schematic diagram of a single flyback topology with a single secondary side branch in related technologies; Figure 3 This is a schematic diagram of a single anti-excitation topology with multiple secondary side branches in related technologies; Figure 4 This is a schematic diagram of a dual flyback topology with multiple secondary side branches in related technologies; Figure 5 This is an exemplary circuit diagram illustrating an embodiment of the flyback power supply circuit of this application.
[0019] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation
[0020] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.
[0021] It should be noted that if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Furthermore, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution that simultaneously satisfies A and B. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.
[0022] Flyback topologies are widely used in switching power supplies, commonly found in single-secondary-side and multi-secondary-side topologies. In both of these topologies, the primary side is typically a single primary-side branch. In switching power supply scenarios using multiple flyback topologies, especially when each flyback has multiple secondary-side branches, a separate primary-side control circuit needs to be designed for each primary-side branch. This primary-side control circuit must include at least one controller and one switching transistor, thus requiring at least the same number of controllers and switching transistors as the number of flyback topologies.
[0023] Therefore, current multi-flyback topology switching power supplies suffer from problems such as complex circuit structure, large space occupation, and high cost.
[0024] To address the aforementioned problems, this application provides a flyback power supply circuit and a switching power supply. The application and its embodiments will be described below with reference to the accompanying drawings.
[0025] This application proposes a flyback power supply circuit.
[0026] In one embodiment of the flyback power supply circuit, refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of this embodiment. The flyback power supply circuit may include multiple transformers, a detection feedback module, a control module and a switch drive module. The transformer includes a primary winding and several secondary windings. For each transformer, the primary winding is connected in parallel to a primary branch, and several secondary windings are connected to several secondary branches. Any one of the several secondary branches is a feedback branch. One end of each primary branch corresponding to multiple transformers is connected in parallel and serves as the positive input terminal of the flyback power supply circuit. The other end of each primary branch is connected to the first terminal of the switch drive module. The second terminal of the switch drive module serves as the negative input terminal of the flyback power supply circuit. Each feedback branch corresponding to multiple transformers is connected to the detection feedback module. The detection feedback module is connected to the control module. The control module is connected to the control terminal of the switch drive module.
[0027] Reference Figure 2 , Figure 3 and Figure 4 , Figure 2 This is a schematic diagram of a single flyback topology with a single secondary side branch in related technologies. Figure 3 This is a schematic diagram of a single anti-excitation topology with multiple secondary side branches in related technologies. Figure 4 This is a schematic diagram of a multi-flyback topology with multiple secondary side branches in related technologies. In related technologies, such as... Figure 2The single flyback topology with a single secondary branch shown contains only one secondary branch. The output voltage control process of this topology is as follows: the output voltage Vout1 of this secondary branch is directly used as the feedback voltage and input to the control chip U1. The control chip U1 then uses closed-loop control to adjust the duty cycle of the switching transistor Q1, thereby regulating the output voltage Vout1 and achieving closed-loop control and output regulation. Figure 3 The single flyback topology with multiple secondary branches shown includes multiple secondary branches. The output voltage control process of this topology is as follows: A first secondary branch is selected from the multiple secondary branches, and its output voltage Vout11 is used as the feedback voltage, input to the control chip U1. The control chip U1 then adjusts the output voltage Vout11. For the other secondary branches, the proportional relationship can be determined by the turns ratio between each secondary winding of the transformer and the first secondary winding. Based on the voltage ratio equaling the turns ratio, the output voltage of the other secondary branches is controlled, thereby realizing the control and output regulation of multiple secondary branches. In practical applications, there are inevitably scenarios requiring more outputs. If directly... Figure 3 In a single flyback topology with multiple secondary branches, adding more secondary branches increases the complexity of transformer design, raises the cost of secondary winding construction, and worsens coupling, ultimately affecting the overall topology performance. Therefore, multi-flyback topologies, such as... Figure 4 The double flyback topology with multiple side branches shown is in Figure 3 Based on the single flyback topology, another flyback topology is introduced in parallel with it. The parallel connection of the first and second flyback topologies enables the output of more secondary branches. The output voltage control process is similar to... Figure 3 Consistent, and the two flyback topologies are independently controlled; by Figure 4 It can be seen that the newly introduced second flyback topology requires repeated primary devices, namely the switching transistor Q2 and the control chip U2. As a result, the dual flyback topology structure includes at least two switching transistors Q1 and Q2 and two control chips U1 and U2, making the circuit structure more complex and significantly increasing the cost and PCB layout area.
[0028] for Figure 4In a dual flyback topology with multiple secondary branches, if the control chip U2 is removed and the two switches Q1 and Q2 are instead regulated by a single control chip U1, the output voltage control process becomes as follows: The first secondary branch is selected from the multiple secondary branches of the first flyback topology, and its output voltage Vout11 is used as the feedback voltage and input to the control chip U1. The control chip U1 then controls the drive duty cycle of switch Q1, and simultaneously controls switch Q2 with the same drive duty cycle to adjust the output voltages Vout11 and Vout21. Similarly, for the two flyback topologies, the outputs of other secondary branches are controlled in the same way, thus achieving control and output regulation of the multiple secondary branches of the dual flyback topology. Compared to other methods... Figure 4 While the independent control of the two flyback topologies simplifies the topology structure, the feedback from the control chip U1 comes only from the first flyback topology. This results in poor output control and regulation accuracy of the first secondary branch of the second flyback topology, which in turn leads to even worse output control and regulation accuracy of the other secondary branches of the second flyback topology. Consequently, this affects the overall output voltage control and regulation accuracy of the dual flyback topology.
[0029] In this embodiment, as Figure 1 As shown, a flyback power supply circuit with a multi-flyback topology is constructed from multiple transformers, a detection feedback module, a control module, and a switch drive module. Each transformer includes a primary winding and several secondary windings. For each transformer, the primary winding is connected in parallel to a primary branch, and the several secondary windings are correspondingly connected to several secondary branches. For example, the primary winding of transformer T1 is connected in parallel to primary branch 1, and the n secondary windings of transformer T1 are correspondingly connected to n secondary branches 11, 12, ..., 1n; the primary winding of transformer T2 is connected in parallel to primary branch 2, and the n secondary windings of transformer T2 are correspondingly connected to n secondary branches 21, 22, ..., 2n. Among the several secondary branches, one can be arbitrarily selected as the feedback branch. For example, for transformer T1, secondary branch 11 is used as the feedback branch, and for transformer T2, secondary branch 21 is used as the feedback branch.
[0030] In this embodiment, as Figure 1As shown, one end of each primary branch corresponding to multiple transformers is connected in parallel and serves as the positive input terminal of the flyback power supply circuit. For example, one end of primary branch 1, primary branch 2, ..., primary branch m is connected in parallel. The other ends of each primary branch are connected to the first terminal of the switch driver module. For example, the other ends of primary branch 1, primary branch 2, ..., primary branch m are respectively connected to the first terminal of the switch driver module. The second terminal of the switch driver module directly serves as the negative input terminal of the flyback power supply circuit. Multiple feedback branches corresponding to multiple transformers are connected to the detection feedback module. For example, secondary branch 11, secondary branch 21, ..., secondary branch m1 are all feedback branches. These m feedback branches are respectively connected to the detection feedback module, which is connected to the control module. The control module is also connected to the control terminal of the switch driver module.
[0031] Understandably, by connecting one end of multiple primary branches in parallel, the number of transformers and the number of secondary branches within each transformer can be set according to actual needs. This approach facilitates the expansion of more secondary branches and meets the requirements of more practical scenarios. Simultaneously connecting one end of multiple primary branches in parallel, and reusing a switch driver module and a control module, simplifies the circuit structure, reduces PCB board space, and lowers costs. Furthermore, multiple feedback branches ensure that the output voltage of each transformer is considered. Compared to a multi-flyback topology with only one feedback branch, this circuit improves the output voltage control and regulation accuracy of the multiple secondary branches in the multi-flyback topology.
[0032] The flyback power supply circuit provided in this embodiment includes multiple transformers, a detection feedback module, a control module, and a switch drive module. Each transformer includes a primary winding and several secondary windings. The circuit also includes a primary branch connected in parallel with the primary winding in each transformer, and several secondary branches corresponding to the secondary windings, forming a multi-flyback topology with multiple secondary branches. For this topology, one end of each primary branch corresponding to the multiple transformers is connected in parallel and used as the positive input terminal of the flyback power supply circuit. The number of secondary branches can be expanded as needed to adapt to more scenarios. The other end of each primary branch is connected to the first... One end is connected, and the second end of the switch driver module serves as the negative input terminal of the flyback power supply circuit. Any one of the secondary branches is used as the feedback branch. Multiple feedback branches corresponding to multiple transformers are connected to the detection feedback module. The detection feedback module is connected to the control module, and the control module is connected to the control terminal of the switch driver module. Even with a multi-flyback topology, only one control module and one switch driver module are required, simplifying the circuit structure, reducing the space occupied, thereby reducing the PCB board area and lowering the cost. Moreover, this application can achieve high-precision adjustable output voltage control while ensuring that all multiple outputs of the circuit can work normally.
[0033] In one specific implementation, such as Figure 1 As shown, there are multiple transformers including m transformers, where m ≥ 2 and m is a positive integer; multiple primary side branches including m primary side branches; several secondary windings including n secondary windings, where n is a positive integer; several secondary side branches including n secondary side branches; m transformers correspond to m × n secondary side branches; and multiple feedback branches including m feedback branches.
[0034] In this flyback power supply circuit, the detection feedback module is used to detect the output voltage of each feedback branch to obtain m output voltages; the control module is used to perform a weighted average of the m output voltages to obtain the feedback voltage; the output voltage of each of the m feedback branches is adjusted according to the feedback voltage to obtain the corresponding m first adjustment voltages; and, for each transformer, the adjustment voltage of each of the remaining secondary branches is calculated according to the first adjustment voltage and the turns ratio of the secondary winding corresponding to the feedback branch to the secondary winding corresponding to the other secondary branches to obtain n-1 second adjustment voltages, so as to obtain m×(n-1) second adjustment voltages corresponding to the m transformers; and a pulse modulation signal is generated according to the m first adjustment voltages and m×(n-1) second adjustment voltages to dynamically adjust the on / off state of the switch drive module to realize the adjustment of the output voltage of the m×n secondary branches.
[0035] like Figure 1 As shown, taking secondary branch 11, secondary branch 21, ..., secondary branch m1 as feedback branches as an example, after the detection feedback module detects the output voltage of each feedback branch, it obtains m corresponding output voltages Vout11, Vout21, ..., Voutm1. Figure 1(Not shown in the diagram). After receiving m output voltages, the control module performs a weighted average of the m output voltages to obtain the feedback voltage. Then, based on this feedback voltage, or possibly in conjunction with the input voltage Vin, the output voltage of each of the m feedback branches is adjusted to obtain the adjusted voltage corresponding to the m feedback branches, namely secondary branch 11, secondary branch 21, ..., secondary branch m1, which is the first adjusted voltage. Simultaneously, since other secondary branches in the transformer also need to adjust their outputs, the control module can also adjust the output voltage of each transformer based on the adjusted voltage of the feedback branch (i.e., the first adjusted voltage) and the feedback branch... The turns ratio of the secondary winding corresponding to the feedback branch to the secondary winding of the other secondary branches is used to calculate the adjustment voltage of each of the remaining secondary branches. This yields the adjustment voltage of n-1 secondary branches other than the feedback branch, which is equivalent to n-1 second adjustment voltages. The m transformers will correspond to m×(n-1) second adjustment voltages. Then, the control module can generate pulse modulation signals based on the m first adjustment voltages and the m×(n-1) second adjustment voltages to dynamically adjust the switching of the switch drive module, thereby adjusting the output voltage of the m×n secondary branches.
[0036] For example, refer to Figure 5 , Figure 5 This is an exemplary circuit schematic diagram provided in this embodiment. The flyback power supply circuit has two flyback topologies, specifically including two transformers T1 and T2. Each transformer T1 and T2 includes a primary winding and n secondary windings. The primary winding Np1 of transformer T1 is connected in parallel with a primary branch 1, and the n secondary windings of transformer T1 are correspondingly connected to n secondary branches 11, 12, ..., 1n, where secondary branch 11 is the feedback branch. The primary winding Np2 of transformer T2 is connected in parallel with a primary branch 2, and the n secondary windings of transformer T2... There are n secondary side branches 21, 22, ..., 2n, where secondary side branch 21 is a feedback branch; one end of each of the two primary side branches corresponding to the two transformers is connected in parallel and serves as the positive input terminal + of the flyback power supply circuit, and the other end of each of the two primary side branches is connected to the first terminal of the switch driver module. The second terminal of the switch driver module serves as the negative input terminal - of the flyback power supply circuit. Each of the two feedback branches corresponding to the two transformers is connected to the detection feedback module, which is connected to the control module. The control module is also connected to the control terminal of the switch driver module.
[0037] In this embodiment, a weighted average feedback method is used to obtain the feedback voltage. This method takes into account the actual output voltage of at least one secondary branch of each flyback topology. The feedback voltage is obtained by comprehensively considering this actual output voltage. Subsequent output voltage control and regulation based on this feedback voltage will better meet the actual output requirements, thus ensuring the output voltage control and regulation accuracy of each flyback topology. This improves the output voltage control and regulation accuracy of flyback power supply circuits with multiple flyback topologies. In addition to its advantages such as the ability to expand secondary branches, simple circuit structure, fewer components, low cost, and the ability to reduce PCB area and increase power density, this flyback power supply circuit can also improve the output voltage control and regulation accuracy.
[0038] In one alternative implementation, such as Figure 5 As shown, the control module includes controller U10. Controller U10 can be a programmable controller such as an MCU (Microcontroller Unit), a control chip, or a logic processing chip; no specific limitation is made here.
[0039] In one optional implementation, the detection feedback module may include m detection resistors and a voltage divider resistor; one end of each of the m detection resistors is connected to the positive output terminal of the m feedback branches, and the other end of each of the m detection resistors is connected to the feedback terminal of the control module and one end of the voltage divider resistor, respectively, with the other end of the voltage divider resistor grounded.
[0040] like Figure 5 As shown, the detection feedback module specifically includes detection resistor R13, detection resistor R15, and voltage divider resistor R16; one end of R13 is connected to the positive output terminal of feedback branch 11, one end of R15 is connected to the positive output terminal of feedback branch 21, the other ends of R13 and R15 are respectively connected to the feedback terminal FB of controller U10 and one end of R16, and the other end of R16 is grounded.
[0041] In this embodiment, the output voltage of the feedback branch is detected by resistor voltage division, which requires fewer components and has a lower cost.
[0042] In one optional implementation, the switch driving module may include a switching transistor; the drain of the switching transistor serves as the first terminal of the switch driving module and is connected to the other end of each of the m primary side branches; the source of the switching transistor serves as the second terminal of the switch driving module; and the gate of the switching transistor serves as the control terminal of the switch driving module and is connected to the driving terminal of the control module.
[0043] Understandably, the switching transistor can be a field-effect transistor such as a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), a JFET (Junction Field-Effect Transistor), an IGBT (Insulated Gate Bipolar Transistor), or a controllable switching transistor such as a power semiconductor switch (e.g., gallium nitride power semiconductor, silicon carbide power device). In practical applications, the appropriate transistor can be selected as needed, and no specific limitation is made here.
[0044] like Figure 5 As shown, the switch driving module specifically includes a switch transistor Q10. The drain of Q10 serves as the first terminal of the switch driving module and is connected to the other end of primary side branch 1 and the other end of primary side branch 2, respectively. The source of Q10 serves as the second terminal of the switch driving module, and the gate of Q10 serves as the control terminal of the switch driving module and is connected to the drive terminal GATE of the controller U10.
[0045] Furthermore, the switch driver module may also include a drain-source capacitor; one end of the drain-source capacitor is connected to the drain of the switching transistor, and the other end of the drain-source capacitor is connected to the source of the switching transistor.
[0046] like Figure 5 As shown, the switch drive module also specifically includes a drain-source capacitor Cq, one end of which is connected to the drain of the switch transistor Q10, and the other end of which is connected to the source of the switch transistor Q10.
[0047] In this embodiment, the control module can reverse the conduction time of the switching transistor by acquiring the feedback voltage, dynamically balance energy transfer, and ultimately achieve precise voltage regulation. When the switching transistor is turned off, the leakage inductance of the transformer will form a high-frequency resonant circuit with the junction capacitance of the switching transistor, generating a large voltage spike. The drain-source capacitor connected in parallel between the drain and source of the switching transistor can form an LC resonance with the leakage inductance. By absorbing the spike energy and slowing down the rise rate of the drain-source voltage of the switching transistor, the purpose of protecting the switching transistor is achieved, and the turn-on loss of the switching transistor can be reduced.
[0048] In one optional embodiment, each primary branch includes a first resistor, a first capacitor, and a first diode; one end of the first resistor and one end of the first capacitor are connected in parallel and serve as one end of the primary branch, and the other end of the first resistor and the other end of the first capacitor are respectively connected to the negative terminal of the first diode, and the positive terminal of the first diode serves as the other end of the primary branch.
[0049] like Figure 5As shown, primary branch 1 includes a first resistor R1, a first capacitor C1, and a first diode D1. One end of R1 and one end of C1 are connected in parallel, serving as one end of primary branch 1. The other ends of R1 and C1 are respectively connected to the negative terminal of D1, and the positive terminal of D1 serves as the other end of primary branch 1. Figure 5 As shown, the circuit structure of the primary branch 2 is similar, and will not be described in detail here.
[0050] In one optional embodiment, each secondary branch includes a second diode, a second capacitor, and a second resistor; the anode of the second diode serves as the first terminal of the secondary branch, which is connected to one end of the corresponding secondary winding; the cathode of the second diode is connected to one end of the second capacitor and one end of the second resistor, serving as the second terminal of the secondary branch and the positive output terminal of the flyback power supply circuit; the other end of the second capacitor and the other end of the second resistor are connected in parallel, serving as the third terminal of the secondary branch; the third terminal of the secondary branch is connected to the other end of the corresponding secondary winding, and also serves as the negative output terminal of the flyback power supply circuit.
[0051] like Figure 5 As shown, the secondary branch 11 includes a second diode D11, a second capacitor C11, and a second resistor R11. The positive terminal of D11 serves as the first terminal of the secondary branch 11, which is connected to one end of the corresponding secondary winding Ns11. The negative terminal of D11 is connected to one end of C11 and one end of R11, serving as the second terminal of the secondary branch 11 and the positive output terminal of one of the multiple outputs of the flyback power supply circuit. The other end of C11 and the other end of R11 are connected in parallel, serving as the third terminal of the secondary branch 11. The third terminal of the secondary branch is connected to the other end of the corresponding secondary winding Ns11 and also serves as the negative output terminal of one of the multiple outputs of the flyback power supply circuit. Figure 5 The circuit structures of secondary branches 12, ..., 1n and 21, 22, ..., 2n are similar and will not be described in detail here.
[0052] In one alternative embodiment, the flyback power supply circuit may further include a bus capacitor; one end of the bus capacitor is connected to the positive input terminal of the flyback power supply circuit, and the other end of the bus capacitor is connected to the negative input terminal of the flyback power supply circuit.
[0053] like Figure 5 As shown, the flyback power supply circuit also specifically includes a bus capacitor Cbus. One end of Cbus is connected to the positive input terminal + of the flyback power supply circuit, and the other end of Cbus is connected to the negative input terminal - of the flyback power supply circuit.
[0054] For example, Figure 5In the flyback power supply circuit, its working principle is as follows: Transformer T1 performs voltage conversion on the input voltage Vin to obtain multiple output voltages Vout11, Vout12, ..., Vout1n; transformer T2 performs voltage conversion on the input voltage Vin to obtain multiple output voltages Vout21, Vout22, ..., Vout2n; detection resistor R13 and voltage divider resistor R16 can detect the output voltage Vout11 of the secondary branch 11, which serves as the feedback branch; detection resistor R15 and voltage divider resistor R16 can detect the output voltage Vout21 of the secondary branch 21, which serves as the feedback branch; controller U10 receives the output voltages Vout11 and Vout21 respectively, and then processes the input voltages... The output voltages Vout11 and Vout21 are weighted and averaged to obtain the feedback voltage. The output voltages of the two feedback branches are then adjusted based on this feedback voltage to obtain two corresponding first adjustment voltages: the adjusted Vout11 and the adjusted Vout21. The controller U10 also calculates the adjustment voltages for the transformer T1 based on the first adjustment voltage Vout11 and the turns ratios of the secondary winding Ns11 corresponding to the feedback branch (secondary branch 11) and the secondary windings Ns12, ..., Ns1n corresponding to the other secondary branches (secondary branches 12, ..., 1n), to obtain n-1 second adjustment voltages: the adjusted Vout12, ..., the adjusted Vout21. For transformer T2, based on the first adjustment voltage Vout21 and the turns ratio of the secondary winding Ns21 corresponding to the feedback branch (i.e., secondary branch 21) to the secondary winding Ns22, ..., Ns2n corresponding to the other secondary branches (i.e., secondary branches 22, ..., secondary branches 2n), the adjustment voltage of each of the remaining secondary branches is calculated, resulting in n-1 second adjustment voltages, i.e., the adjusted Vout22, ..., adjusted Vout2n, thus obtaining 2(n-1) second adjustment voltages corresponding to the two transformers; after the controller U10 obtains the two first adjustment voltages and the 2(n-1) second adjustment voltages, it generates... The pulse modulation signal dynamically adjusts the on / off state of the switching transistor Q10 through the feedback loop. Specifically, when the switching transistor Q10 is on, the voltage polarity of each secondary winding of transformers T1 and T2 is opposite to the input voltage Vin, and the diodes in each secondary branch are cut off. At this time, energy is stored in the air gap of transformers T1 and T2 by the primary winding. When the switching transistor Q10 is off, the transformer flux is reset, and each secondary winding of transformers T1 and T2 is turned on. Each secondary branch is working, and the stored energy is released through multiple secondary windings, outputting energy at the second and third terminals of each secondary branch. That is, 2n secondary branches correspond to 2n output voltages, realizing the control and adjustment of the output voltage of 2n secondary branches.
[0055] In this embodiment, the primary side branches in the multi-flyback topology are connected in parallel, and the switching transistor Q10 and the controller U10 are reused. The multiple outputs are combined and weighted averaged and fed back to the controller U10. The controller U10 controls and adjusts the output voltage of each secondary side branch. The control accuracy is high, the circuit structure is simple and the cost is low, which is conducive to reducing the PCB board area and improving the power density of the circuit.
[0056] This application also proposes a switching power supply.
[0057] In one embodiment of the switching power supply, the switching power supply may include a flyback power supply circuit.
[0058] It should be noted that the specific structure of the flyback power supply circuit can be referred to the above embodiments. Since the switching power supply adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be elaborated here.
[0059] The above are only some embodiments of this application and do not limit the scope of protection of this application. All equivalent structural transformations made under the technical concept of this application and using the content of this application specification and drawings, or direct / indirect applications in other related technical fields, are included in the scope of protection of this application.
Claims
1. A flyback power supply circuit, characterized in that, It includes multiple transformers, a detection feedback module, a control module, and a switch drive module. The transformer includes a primary winding and several secondary windings. For each of the transformers, the primary winding is connected in parallel with a primary branch, and the plurality of secondary windings are connected to a plurality of secondary branches, and any one of the plurality of secondary branches is a feedback branch. One end of each of the primary side branches corresponding to multiple transformers is connected in parallel and serves as the positive input terminal of the flyback power supply circuit. The other end of each of the multiple primary side branches is connected to the first terminal of the switch drive module. The second terminal of the switch drive module serves as the negative input terminal of the flyback power supply circuit. Each of the multiple feedback branches corresponding to multiple transformers is connected to the detection feedback module. The detection feedback module is connected to the control module. The control module is connected to the control terminal of the switch drive module.
2. The flyback power supply circuit as described in claim 1, characterized in that, The plurality of transformers includes m transformers, where m ≥ 2 and m is a positive integer; the plurality of primary side branches includes m primary side branches; the plurality of secondary side windings includes n secondary side windings, where n is a positive integer; the plurality of secondary side branches includes n secondary side branches; the m transformers correspond to m × n secondary side branches; and the plurality of feedback branches includes m feedback branches.
3. The flyback power supply circuit as described in claim 2, characterized in that, The detection feedback module is used to detect the output voltage of each of the feedback branches to obtain m output voltages; The control module is used to perform a weighted average of the m output voltages to obtain the feedback voltage; The output voltage of each of the m feedback branches is adjusted according to the feedback voltage to obtain m corresponding first adjustment voltages; and for each transformer, the adjustment voltage of each of the remaining secondary branches is calculated according to the first adjustment voltage and the turns ratio of the secondary winding corresponding to the feedback branch to the secondary winding corresponding to the other secondary branches to obtain n-1 second adjustment voltages, so as to obtain m×(n-1) second adjustment voltages corresponding to the m transformers; and a pulse modulation signal is generated according to the m first adjustment voltages and the m×(n-1) second adjustment voltages to dynamically adjust the on / off state of the switch drive module, thereby realizing the adjustment of the output voltage of the m×n secondary branches.
4. The flyback power supply circuit as described in claim 2, characterized in that, The detection feedback module includes m detection resistors and one voltage divider resistor; One end of each of the m detection resistors is connected to the positive output terminal of each of the m feedback branches, and the other end of each of the m detection resistors is connected to the feedback terminal of the control module and one end of the voltage divider resistor, respectively. The other end of the voltage divider resistor is grounded.
5. The flyback power supply circuit as described in claim 2, characterized in that, The switch driver module includes a switching transistor; The drain of the switching transistor serves as the first terminal of the switching drive module and is connected to the other end of each of the m primary side branches. The source of the switching transistor serves as the second terminal of the switching drive module, and the gate of the switching transistor serves as the control terminal of the switching drive module and is connected to the drive terminal of the control module.
6. The flyback power supply circuit as described in claim 5, characterized in that, The switch driving module also includes a drain-source capacitor; One end of the drain-source capacitor is connected to the drain of the switching transistor, and the other end of the drain-source capacitor is connected to the source of the switching transistor.
7. The flyback power supply circuit as described in claim 1, characterized in that, Each of the primary side branches includes a first resistor, a first capacitor, and a first diode; One end of the first resistor and one end of the first capacitor are connected in parallel and serve as one end of the primary branch. The other end of the first resistor and the other end of the first capacitor are respectively connected to the negative terminal of the first diode, and the positive terminal of the first diode serves as the other end of the primary branch.
8. The flyback power supply circuit as described in claim 1, characterized in that, Each of the secondary side branches includes a second diode, a second capacitor, and a second resistor; The positive terminal of the second diode serves as the first end of the secondary branch, which is connected to one end of the corresponding secondary winding. The negative terminal of the second diode is connected to one end of the second capacitor and one end of the second resistor, and serves as the second end of the secondary branch and the positive output terminal of the flyback power supply circuit. The other end of the second capacitor and the other end of the second resistor are connected in parallel, and serve as the third end of the secondary branch. The third end of the secondary branch is connected to the other end of the corresponding secondary winding, and also serves as the negative output terminal of the flyback power supply circuit.
9. The flyback power supply circuit as described in any one of claims 1 to 8, characterized in that, This also includes bus capacitors; One end of the bus capacitor is connected to the positive input terminal of the flyback power supply circuit, and the other end of the bus capacitor is connected to the negative input terminal of the flyback power supply circuit.
10. A switching power supply, characterized in that, Includes the flyback power supply circuit as described in any one of claims 1 to 9.