Control module of asymmetric half-bridge flyback conversion module and switching power supply

Abstract

The utility model relates to a control module of an asymmetric half-bridge flyback conversion module and a switching power supply. The control module of the asymmetric half-bridge flyback conversion module comprises a sampling circuit, an isolation comparison circuit and a control circuit. The sampling circuit is connected with the primary side and the secondary side of the asymmetric half-bridge flyback conversion module, and is used for collecting the voltage of the resonant capacitor on the primary side and outputting the corresponding primary voltage, and collecting the output voltage on the secondary side and outputting the corresponding secondary voltage. And the isolation comparison circuit is connected with the sampling circuit and is used for outputting a corresponding control signal according to the magnitude relationship between the primary voltage and the secondary voltage. The control circuit is connected with the isolation comparison circuit, the primary side and the secondary side and used for adjusting the closing time of the primary side switch tube and the secondary side switch tube based on the control signal. Therefore, the conditions of positive current pouring and backward current pouring can be avoided, the problem of abnormal current is effectively solved, and the reliability of the circuit is improved.

Description

Technical Field

[0001] The present application relates to the field of circuit technology, and in particular to a control module and a switching power supply of an asymmetric half-bridge flyback conversion module. Background Art

[0002] With the rapid development of power electronics, switching converters are being used more and more widely. Compared with conventional flyback circuits, the AHB (Asymmetric half bridge) architecture can achieve zero-voltage turn-on of two switches, recover leakage inductance energy, and easily realize self-driven synchronous rectification under the conditions of similar number of components and complexity. It can effectively improve efficiency while reducing the size of the transformer, meeting people's requirements for high power density, high reliability and compact design.

[0003] like Figure 1 As shown, the AHB flyback conversion module includes a primary side and a secondary side. The primary side includes an input filter capacitor C1, a half-bridge structure composed of a switch tube S1 and a switch tube S2, a transformer primary winding, and a resonant capacitor Cr connected to the primary winding. The secondary side includes a transformer secondary winding, an output filter capacitor, and a switch tube S3. In real-time implementation, the working states of the switches S1 and S2 on the primary side are controlled by the AHB controller, and the working state of the switch tube S3 is controlled by the SR (Synchronous Rectifier) ​​controller, so that energy is transferred from the primary side to the secondary side, and the secondary side provides an output voltage Vo to power the output load.

[0004] At present, in the application of AHB architecture, when there is a large change in output load or a sudden change in output voltage such as output voltage switching, high peak current is likely to occur. The high peak current may exceed the rated specifications of the power device and cause equipment failure. Utility Model Content

[0005] Based on this, it is necessary to provide a control module and a switching power supply of an asymmetric half-bridge flyback conversion module that can improve current abnormality when the output voltage suddenly changes in order to solve the above technical problems.

[0006] A control module of an asymmetric half-bridge flyback conversion module, comprising:

[0007] A sampling circuit, connected to the primary side and the secondary side of the asymmetric half-bridge flyback conversion module, for collecting the voltage of the primary side resonant capacitor and outputting the corresponding primary voltage, and collecting the output voltage of the secondary side and outputting the corresponding secondary voltage;

[0008] An isolation comparison circuit, connected to the sampling circuit, and configured to output a corresponding control signal according to a magnitude relationship between the primary voltage and the secondary voltage;

[0009] A control circuit is connected to the isolation comparison circuit, the primary side and the secondary side respectively, and is used to adjust the closing time of the primary side and the secondary side switch tubes based on the control signal.

[0010] In one embodiment, the sampling circuit includes a primary sampling unit and a secondary sampling unit, the primary sampling unit is connected to the resonant capacitor of the primary side, and the secondary sampling unit is connected to the output filter capacitor of the secondary side.

[0011] In one embodiment, the primary sampling unit includes a first resistor and a second resistor, the first end of the first resistor is connected to the first end of the resonant capacitor, the second end of the first resistor is connected to the second end of the resonant capacitor through the second resistor, and the second end of the first resistor is also connected to the isolation comparison circuit.

[0012] In one embodiment, the secondary sampling unit includes a third resistor and a fourth resistor, the first end of the third resistor is connected to the first end of the output filter capacitor, the second end of the third resistor is connected to the second end of the output filter capacitor through the fourth resistor, and the second end of the third resistor is also connected to the isolation comparison circuit.

[0013] In one embodiment, the isolation comparison circuit includes an isolation module and a comparison module connected to each other, the isolation module is connected to the sampling circuit, and the comparison module is connected to the control circuit.

[0014] In one embodiment, the control circuit includes a primary side controller and a secondary side controller connected to the isolation comparison circuit, wherein the primary side controller is connected to the primary side, and the secondary side controller is connected to the secondary side.

[0015] In one of the embodiments, the control circuit includes a feedback controller, an input controller and an output controller;

[0016] Wherein, the first end of the feedback controller is connected to the isolation comparison circuit, the second end of the feedback controller is connected to the first end of the input controller, and the third end of the feedback controller is connected to the first end of the output controller;

[0017] The second end of the input controller is connected to the primary side, and the second end of the output controller is connected to the secondary side.

[0018] In one embodiment, the feedback controller and the isolation comparison circuit are integrated into the same module.

[0019] In one embodiment, the sampling circuit, the isolation comparison circuit and the control circuit are integrated into the same module.

[0020] A switching power supply comprises: an asymmetric half-bridge flyback conversion module and a control module of the asymmetric half-bridge flyback conversion module as described above.

[0021] The control module and the switching power supply of the above-mentioned asymmetric half-bridge flyback conversion module include a sampling circuit, an isolation comparison circuit and a control circuit. The sampling circuit is connected to the primary side and the secondary side of the asymmetric half-bridge flyback conversion module, and is used to collect the voltage of the primary side resonant capacitor and output the corresponding primary voltage, collect the output voltage of the secondary side and output the corresponding secondary voltage. The isolation comparison circuit is connected to the sampling circuit, and is used to output a corresponding control signal according to the magnitude relationship between the primary voltage and the secondary voltage. The control circuit is respectively connected to the isolation comparison circuit, the primary side and the secondary side, and is used to adjust the closing time of the primary side and the secondary side switch tube based on the control signal. Therefore, under the working conditions such as the output load has a large change or the output voltage is switched, when the primary voltage and the secondary voltage are unbalanced, the control circuit can adjust the closing time of the primary side and the secondary side switch tube to extend the closing time of the primary side switch tube or the secondary side switch tube, increase the discharge time of the primary side resonant capacitor or the secondary side output filter capacitor, so that the energy of the primary side and the secondary side is balanced, and the current forward and reverse inflow are avoided, thereby effectively solving the current abnormality problem and improving the reliability and stability of the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of a partial circuit structure of an AHB flyback conversion module and a corresponding controller;

[0023] Figure 2 for Figure 1 An equivalent circuit diagram of the AHB flyback converter module;

[0024] Figure 3 for Figure 1 Another equivalent circuit diagram of the AHB flyback converter module;

[0025] Figure 4 for Figure 1 Another equivalent circuit diagram of the AHB flyback converter module;

[0026] Figure 5 is a schematic diagram of a control module of an asymmetric half-bridge flyback conversion module in one embodiment;

[0027] Figure 6 is a schematic diagram of a control module of an asymmetric half-bridge flyback conversion module in another embodiment;

[0028] Figure 7 A schematic diagram of a control module of an asymmetric half-bridge flyback conversion module in yet another embodiment;

[0029] Figure 8 A schematic diagram of a control module of an asymmetric half-bridge flyback conversion module in yet another embodiment;

[0030] Fig. 9 FIG. 4 is a schematic diagram of a control module of an asymmetric half-bridge flyback conversion module in yet another embodiment. DETAILED DESCRIPTION

[0031] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. Embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0033] It is understood that the terms "first", "second", etc. used in this application may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish a first element from another element. For example, without departing from the scope of this application, a first resistor may be referred to as a second resistor, and similarly, a second resistor may be referred to as a first resistor. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

[0034] It can be understood that the “connection” in the following embodiments should be understood as “electrical connection”, “communication connection”, etc. if the connected circuits, modules, units, etc. have electrical signals or data transmission between each other.

[0035] It can be understood that “at least one” means one or more, “plurality” means two or more, and “at least part of an element” means part or all of an element.

[0036] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. At the same time, the term "and / or" used in this specification includes any and all combinations of the relevant listed items.

[0037] As described in the background technology, the flyback conversion module of the AHB architecture has greatly improved performance compared to the current conventional flyback circuit. At the same time, due to the working mode, energy can be stored in the transformer and the resonant capacitor at the same time, which reduces the size of the transformer and provides an effective solution for compact design.

[0038] However, the current AHB architecture flyback converter module has the following problems in application: when the output load changes significantly or the secondary voltage signal switches, such as when the load is suddenly plugged in or out, or in the application scenario of a PD charging device (a power adapter device using the PD protocol), high peak current is likely to occur, damaging the power devices (such as the switch tube) in the flyback converter module.

[0039] Based on the above problems, the inventors have found through research that when the output load has a large change or the secondary voltage signal is switched, current backflow and forward flow problems caused by voltage imbalance are likely to occur, resulting in high peak current. Figure 1 The fundamental reason for the above problems is that the voltage Vcr on the resonant capacitor Cr does not match the output voltage Vo on the secondary side. According to the working principle of the flyback conversion module of the AHB architecture, in theory, the voltage Vcr=N*Vo must be maintained at any time to prevent backflow and forward injection (N is the turns ratio of the primary and secondary windings of the transformer).

[0040] Regarding positive current sinking, positive current sinking refers to the process of energy being transferred from the primary side to the secondary side. The clamp switch tube S2 and the output switch tube S3 are both turned on, and the main switch tube S1 is open. The equivalent circuit is as follows: Figure 2 As shown. Theoretically, the voltage Vcr=N*Vo, but because of the sudden change of the secondary output voltage Vo or the load, the primary and secondary equivalent voltages are unbalanced, and the voltage Vcr on the resonant capacitor Cr is greater than N*No. Theoretically, the voltage VL across the primary winding of the transformer is equal to N*Vo. The equivalent DC impedance of the loop is defined as R, then the voltage Vr on the impedance R is equal to Vcr-N*Vo. Because the DC impedance R is very small, a large current I (high peak current) will be generated, and the direction is as follows Figure 3 As indicated by the arrow.

[0041] Regarding the current backflow, the current backflow is opposite to the above positive inflow principle. It is also because the output voltage Vo or the load mutation causes the primary and secondary equivalent voltage to be unbalanced. The voltage Vcr on the resonant capacitor is less than N*Vo. Theoretically, the voltage VL across the primary winding of the transformer is N*Vo. The equivalent DC impedance of the loop is defined as R, then the voltage Vr on the impedance R is N*Vo-Vcr. Because the DC impedance R is very small, a large current I will be generated, and the direction is as follows Figure 4 As indicated by the arrow.

[0042] Based on the principle of generating current forward injection and reverse injection in the flyback conversion module of the above-mentioned AHB architecture, the inventors further studied the technical solution of the embodiment of the present application.

[0043] Specifically, in one embodiment, a control module of an asymmetric half-bridge flyback conversion module is provided, such as Figure 5 As shown, it includes a sampling circuit 100, an isolation comparison circuit 200 and a control circuit 300. The sampling circuit 100 is connected to the primary side and the secondary side of the asymmetric half-bridge flyback conversion module, and is used to collect the voltage Vcr of the resonant capacitor on the primary side and output the corresponding primary voltage; the sampling circuit 100 also collects the output voltage Vo on the secondary side and outputs the corresponding secondary voltage. The isolation comparison circuit 200 is connected to the sampling circuit 100, and is used to compare the primary voltage and the secondary voltage, and output a corresponding control signal according to the magnitude relationship between the primary voltage and the secondary voltage. The control circuit 300 is respectively connected to the isolation comparison circuit 200, the primary side and the secondary side, and the control circuit 300 is used to receive the control signal and adjust the closing time of the primary side switch tube and the secondary side switch tube based on the control signal.

[0044] Specifically, one input terminal of the sampling circuit 100 is connected to the resonant capacitor on the primary side, and the voltage Vcr across the resonant capacitor is collected and output to the first input terminal of the isolation comparison circuit 200 through the first output terminal. The primary voltage corresponds to the capacitor voltage Vcr. Another input terminal of the sampling circuit 100 is connected to the output filter capacitor on the secondary side, and the output voltage Vo is collected through the output filter capacitor, and the corresponding secondary voltage is output to the second input terminal of the isolation comparison circuit 200 through the second output terminal. The secondary voltage corresponds to the output voltage Vo.

[0045] Furthermore, the sampling frequency of the sampling circuit 100 can be set according to actual needs. Since the output load change or the output voltage switching condition is difficult to predict in actual use scenarios, the sampling circuit 100 can collect the voltages of the primary side and the secondary side in real time to monitor the voltage changes of the primary side and the secondary side in real time. In other embodiments, the sampling can also be performed once at intervals, and the interval time can meet the needs.

[0046] The isolation comparison circuit 200 compares the magnitude of the primary voltage and the secondary voltage, and outputs a corresponding control signal through the output terminal. Exemplarily, the control signal includes a first control signal and a second control signal, and the isolation comparison circuit 200 can output the first control signal when the primary voltage is greater than the secondary voltage, and output the second control signal when the primary voltage is less than or equal to the secondary voltage.

[0047] It should be noted that in actual implementation, the sampling circuit will be designed according to the actual circuit parameters of the asymmetric half-bridge flyback conversion module, so that when the primary voltage is equal to the secondary voltage, the capacitor voltage Vcr across the resonant capacitor is equal to N*Vo (where N represents the turns ratio of the primary and secondary windings of the transformer, and Vo represents the output voltage); when the primary voltage is greater than the secondary voltage, the capacitor voltage Vcr>N*Vo; when the primary voltage is less than or equal to the secondary voltage, the capacitor voltage Vcr≤N*Vo. Thus, the size relationship between Vcr and N*Vo can be reflected through the control signal.

[0048] The input end of the control circuit 300 is connected to the output end of the isolation comparison circuit 200 to receive the control signal. The first output end of the control circuit 300 is connected to the clamp switch tube S2 on the primary side, and the second output end is connected to the output switch tube S3 on the secondary side. In actual control, the control circuit 300 can output a drive signal corresponding to the control signal, and the drive signal is used to adjust the closing time of the clamp switch tube S2 and the output switch tube S3. Exemplarily, the drive signal may include a first drive signal and a second drive signal. When the control circuit 300 receives the first control signal, it outputs the first drive signal to extend the closing time of the clamp switch tube S2 on the primary side to increase the discharge time of the resonant capacitor until the primary voltage is equal to the secondary voltage, that is, Vcr=N*Vo, thereby avoiding the current positive injection situation. When receiving the second control signal, the control circuit 300 outputs a second drive signal to extend the closing time of the output switch tube S3 on the secondary side and increase the discharge time of the output filter capacitor until the primary voltage is equal to the secondary voltage, that is, Vcr=N*Vo, thereby avoiding current backflow.

[0049] The control module of the above-mentioned asymmetric half-bridge flyback conversion module includes a sampling circuit 100, an isolation comparison circuit 200 and a control circuit 300. The sampling circuit 100 is used to sample the capacitor voltage Vcr of the resonant capacitor on the primary side and output the corresponding primary voltage, collect the output voltage Vo on the secondary side and output the corresponding secondary voltage. The isolation comparison circuit 200 outputs a corresponding control signal according to the magnitude relationship between the primary voltage and the secondary voltage. The control circuit 300 receives the control signal and adjusts the closing time of the switch tube on the primary side and the switch tube on the secondary side based on the control signal. Therefore, when the output load has a large change or the output voltage is switched, the primary voltage and the secondary voltage are unbalanced, and the control circuit 300 can control the closing time of the primary side switch tube or the secondary side switch tube to extend, increase the discharge time of the resonant capacitor or the output filter capacitor, so that the energy of the primary side and the secondary side is balanced, and the current forward and reverse infusion are avoided, thereby effectively solving the current abnormality problem and improving the reliability and stability of the circuit.

[0050] It should also be noted that in the related art, since the problem of abnormal current has not been solved, technicians in this field need to try to select devices with higher specifications when designing an asymmetric half-bridge flyback conversion module to ensure that the devices are not damaged by high peak currents. However, the cost of devices with higher specifications will also be higher, which increases the overall cost of the asymmetric half-bridge flyback conversion module. In contrast, the control module of the asymmetric half-bridge flyback conversion module in this embodiment can reduce the selection specifications of the asymmetric half-bridge flyback conversion module, ensuring circuit reliability while reducing costs.

[0051] In one embodiment, Figure 6 As shown, the sampling circuit 100 includes a primary sampling unit 110 and a secondary sampling unit 120. The primary sampling unit 110 is connected to the resonant capacitor on the primary side, and the secondary sampling unit 120 is connected to the output filter capacitor on the secondary side.

[0052] Specifically, the primary sampling unit 110 is used to collect the voltage Vcr across the resonant capacitor, and output the primary voltage corresponding to the voltage Vcr through the output terminal to the first input terminal of the isolation comparison circuit 200. The secondary sampling unit 120 collects the output voltage Vo through the output filter capacitor, and outputs the corresponding secondary voltage to the second input terminal of the isolation comparison circuit 200.

[0053] In this embodiment, by respectively providing the primary sampling unit 110 and the secondary sampling unit 120 , isolated sampling of the capacitor voltage Vcr and the output voltage Vo with different voltage levels is achieved, thereby improving the safety of the circuit.

[0054] The specific structures of the primary sampling unit 110 and the secondary sampling unit 120 can be set according to actual conditions. In one embodiment, Figure 7 As shown, the primary sampling unit 110 includes a first resistor R1 and a second resistor R2, wherein the first end of the first resistor R1 is connected to the first end of the resonant capacitor Cr, the second end of the first resistor R1 is connected to the second end of the resonant capacitor Cr through the second resistor R2, and the second end of the first resistor R1 is also connected to the isolation comparison circuit 200.

[0055] The parameters of the first resistor R1 and the second resistor R2 need to be set according to the specific parameters of the circuit during actual implementation. The first resistor R1 and the second resistor R2 can be independent resistors or an equivalent circuit composed of multiple resistors. In this embodiment, the first resistor R1 and the second resistor R2 form a resistor voltage-dividing sampling circuit, and the primary voltage outputted by the circuit is the voltage-dividing voltage of the first resistor R1 and the second resistor R2, thereby realizing the sampling of the voltage Vcr across the resonant capacitor Cr.

[0056] In one embodiment, the secondary sampling unit 120 includes a third resistor R3 and a fourth resistor R4, a first end of the third resistor R3 is connected to a first end of the output filter capacitor Co, a second end of the third resistor R3 is connected to a second end of the output filter capacitor Co through the fourth resistor R4, and a second end of the third resistor R3 is also connected to the isolation comparison circuit 200.

[0057] In this embodiment, the resistor voltage-dividing sampling circuit is formed by the third resistor R3 and the fourth resistor R4, and the secondary voltage outputted by the resistor voltage-dividing sampling circuit is the voltage-dividing circuit of the third resistor R3 and the fourth resistor R4, thereby sampling the output voltage Vo.

[0058] Among them, the parameters of the third resistor R3 and the fourth resistor R4 need to be set according to the specific parameters of the circuit during actual implementation, and the parameters of the first resistor R1, the second resistor R2, the third resistor R3 and the fourth resistor R4 need to match the turns ratio design of the primary and secondary windings of the transformer, so that the magnitude relationship between the voltage division signal of the first resistor R1 and the second resistor R2 and the voltage division signal of the third resistor R3 and the fourth resistor R4 can reflect the magnitude relationship between the capacitor voltage Vcr and N*Vo.

[0059] The circuit combination of the isolation comparison circuit 200 can be set in combination with actual conditions. On the basis of meeting the safety requirements, a fast response speed is also required to meet the needs of rapid control of the control module of the asymmetric half-bridge flyback conversion module. In one embodiment, the isolation comparison circuit 200 can use a high-speed isolation comparator, which can be an integrated chip or a circuit module. One input terminal of the high-speed isolation comparator is connected to the primary voltage, and the other input terminal is connected to the secondary voltage, and the two are compared in size, and a corresponding control signal is output according to the comparison result.

[0060] In another embodiment, the isolation comparison circuit 200 includes an isolation module and a comparison module connected to each other, the isolation module is connected to the sampling circuit 100, and the comparison module is connected to the control circuit 300. The isolation module and the comparison module can be integrated chips or circuit modules, and the chip type of the integrated chip and the circuit structure of the circuit module do not need to be limited, and only need to meet the requirements of primary and secondary signal isolation, comparison and fast processing.

[0061] The specific structure of the control circuit 300 can be set in combination with actual conditions. In one embodiment, the control circuit 300 is an integrated chip, which can receive the control signal output by the isolation comparison circuit 200, and control the switch state of the switch tubes on the primary side and the secondary side based on the control signal. At the same time, the integrated chip can also integrate the corresponding functions of the AHB controller and the SR controller, so as to control the asymmetric half-bridge flyback conversion module to be in different working modes, etc., so that the asymmetric half-bridge flyback conversion module can realize the corresponding function. In this way, the circuit can be simplified and the integration and reliability of the circuit can be improved.

[0062] In another embodiment, Figure 8 As shown, the control circuit 300 includes a primary side controller 310 and a secondary side controller 320 connected to the isolation comparison circuit 200 , wherein the primary side controller 310 is connected to the primary side, and the secondary side controller 320 is connected to the secondary side.

[0063] Specifically, the secondary side controller 320 is connected to the output switch tube S3 of the secondary side, and is used to output a second drive signal for driving the output switch tube S3 according to the control signal. The primary side controller 310 is connected to the clamp switch tube S2 of the primary side, and is used to output a first drive signal for the clamp switch tube S2 according to the control signal. It can be understood that the primary side controller 310 is also connected to the main switch tube S1 of the primary side, and outputs a corresponding signal to control the working state of the main switch tube S1. Since no energy is transmitted to the secondary during the operation of the main switch tube S1, in this embodiment, how the primary side controller 310 controls the working state of the main switch tube S1 is not limited, and those skilled in the art can refer to the commonly used technology in the field for setting during actual implementation. In addition, during actual implementation, those skilled in the art can also set the working process such as how the primary side controller 310 and the secondary side controller 320 control the working mode of the asymmetric half-bridge flyback conversion module according to actual use needs, so that the asymmetric half-bridge flyback conversion module can achieve the corresponding function.

[0064] In one embodiment, Fig. 9 As shown, the control circuit 300 includes a feedback controller 330, an input controller 340 and an output controller 350. The first end of the feedback controller 330 is connected to the isolation comparison circuit 200, the second end of the feedback controller 330 is connected to the first end of the input controller 340, and the third end of the feedback controller 330 is connected to the first end of the output controller 350; the second end of the input controller 340 is connected to the primary side 350, and the second end of the output controller is connected to the secondary side.

[0065] In this embodiment, the feedback controller 320 is used to receive the control signal output by the isolation comparison circuit 200, and output the corresponding feedback signal to the input controller 340 and the output controller 350 according to the control signal. The specific functions of the feedback controller 320 need to be set in combination with the specific structure of the isolation comparison circuit 200 actually selected, such as converting and processing the control signal.

[0066] The output controller 350 is connected to the output switch tube S3 on the secondary side, and is used to output a second drive signal for driving the output switch tube S3 according to the feedback signal. The input controller 340 is connected to the clamp switch tube S2 on the primary side, and is used to output a first drive signal for the clamp switch tube S2 according to the feedback signal. It can be understood that the input controller 340 can also be connected to the main switch tube S1 on the primary side, and output a corresponding signal to control the working state of the main switch tube S1.

[0067] In addition, during actual implementation, technicians in this field can also set the working processes such as how the feedback controller 330, the input controller 340 and the output controller 350 control the working mode of the asymmetric half-bridge flyback conversion module according to actual usage needs, so that the asymmetric half-bridge flyback conversion module can achieve the corresponding function.

[0068] In one embodiment, the feedback controller 330 and the isolation comparison circuit 200 may be integrated into the same module, such as integrated into the same chip, to improve the integration of the circuit.

[0069] Furthermore, the sampling circuit 100, the isolation comparison circuit 200, and the control circuit 300 can also be integrated into the same module, such as designed as an integrated chip. In actual use, it is only necessary to connect the corresponding pins of the chip to the corresponding asymmetric half-bridge flyback conversion module, which can greatly improve the integration level of the circuit and the convenience of use.

[0070] The control module of the asymmetric half-bridge flyback conversion module can timely adjust the energy of the primary side and the secondary side to achieve balance when the output load changes greatly or the output voltage switches, avoiding the situation of positive and reverse current infusion, thereby effectively solving the current abnormality problem and improving the reliability and stability of the circuit. At the same time, the control module of the asymmetric half-bridge flyback conversion module can also reduce the selection specifications of the asymmetric half-bridge flyback conversion module, thereby reducing costs.

[0071] In one embodiment, a switching power supply is provided, including an asymmetric half-bridge flyback conversion module and a control module of the asymmetric half-bridge flyback conversion module. The control module of the asymmetric half-bridge flyback conversion module can be configured with reference to the above embodiments and will not be described in detail.

[0072] In the description of this specification, the description with reference to the terms "some embodiments", "other embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic description of the above terms does not necessarily refer to the same embodiment or example.

[0073] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0074] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A control module of an asymmetric half-bridge flyback converter module, characterized in that: include: A sampling circuit, connected to the primary side and the secondary side of the asymmetric half-bridge flyback conversion module, for collecting the voltage of the primary side resonant capacitor and outputting the corresponding primary voltage, and collecting the output voltage of the secondary side and outputting the corresponding secondary voltage; An isolation comparison circuit, connected to the sampling circuit, and configured to output a corresponding control signal according to a magnitude relationship between the primary voltage and the secondary voltage; A control circuit is connected to the isolation comparison circuit, the primary side and the secondary side respectively, and is used to adjust the closing time of the primary side and the secondary side switch tubes based on the control signal.

2. The control module of the asymmetric half-bridge flyback converter module according to claim 1, characterized in that: The sampling circuit includes a primary sampling unit and a secondary sampling unit. The primary sampling unit is connected to the resonant capacitor on the primary side, and the secondary sampling unit is connected to the output filter capacitor on the secondary side.

3. The control module of the asymmetric half-bridge flyback converter module according to claim 2, characterized in that: The primary sampling unit includes a first resistor and a second resistor, wherein the first end of the first resistor is connected to the first end of the resonant capacitor, the second end of the first resistor is connected to the second end of the resonant capacitor through the second resistor, and the second end of the first resistor is also connected to the isolation comparison circuit.

4. The control module of the asymmetric half-bridge flyback converter module according to claim 2, characterized in that: The secondary sampling unit includes a third resistor and a fourth resistor, the first end of the third resistor is connected to the first end of the output filter capacitor, the second end of the third resistor is connected to the second end of the output filter capacitor through the fourth resistor, and the second end of the third resistor is also connected to the isolation comparison circuit.

5. The control module of the asymmetric half-bridge flyback converter module according to claim 1, characterized in that: The isolation comparison circuit comprises an isolation module and a comparison module connected to each other, the isolation module is connected to the sampling circuit, and the comparison module is connected to the control circuit.

6. The control module of the asymmetric half-bridge flyback converter module according to claim 1, characterized in that: The control circuit includes a primary side controller and a secondary side controller connected to the isolation comparison circuit, wherein the primary side controller is connected to the primary side, and the secondary side controller is connected to the secondary side.

7. The control module of the asymmetric half-bridge flyback converter module according to claim 1, characterized in that: The control circuit includes a feedback controller, an input controller and an output controller; Wherein, the first end of the feedback controller is connected to the isolation comparison circuit, the second end of the feedback controller is connected to the first end of the input controller, and the third end of the feedback controller is connected to the first end of the output controller; The second end of the input controller is connected to the primary side, and the second end of the output controller is connected to the secondary side.

8. The control module of the asymmetric half-bridge flyback converter module according to claim 7, characterized in that: The feedback controller and the isolation comparison circuit are integrated into the same module.

9. The control module of the asymmetric half-bridge flyback converter module according to claim 1, characterized in that: The sampling circuit, the isolation comparison circuit and the control circuit are integrated into the same module.

10. A switching power supply, characterized in that: include: An asymmetric half-bridge flyback conversion module and a control module of the asymmetric half-bridge flyback conversion module as claimed in any one of claims 1 to 9.

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