Flyback switching power supply and power supply device

Abstract

The utility model relates to a flyback switching power supply and a power supply device. The power supply comprises a voltage detection circuit, a switching loop compensation circuit, a power supply management controller and a switching circuit. The input end of the voltage detection circuit is used for being connected with a power supply, and the voltage detection circuit is used for detecting input voltage; the input end of the switching loop compensation circuit is connected with the output end of the voltage detection circuit, and the switching loop compensation circuit is used for outputting an electric signal matched with the voltage detected by the voltage detection circuit; the input end of the power management controller is connected with the output end of the switching loop compensation circuit; the controlled end of the switching circuit is connected with the control end of the power management controller, the input end of the switching circuit is used for being connected with a power supply, and the output end of the switching circuit is grounded. The flyback switching power supply can be suitable for different development boards, and the development cost is saved.

Description

Technical Field

[0001] The present application relates to the technical field of power supply, and in particular to a flyback switching power supply and a battery power supply system. Background Art

[0002] In the current automotive field, there are usually two ways to power motor controllers and motor drivers: drawing power from bus capacitors or drawing power from car batteries. Whether drawing power from bus capacitors or directly from batteries, the power conversion component design must match it.

[0003] Among them, due to problems such as output load jump and input voltage fluctuation, there are strict requirements on the dynamic response and voltage accuracy of the flyback switching power supply in the power conversion component. Usually, loop compensation is used to achieve good stability and dynamic response of the power supply under input voltage fluctuation and load mutation. However, loop compensation is usually targeted, that is, it is only applicable to a specific battery power supply system. Therefore, when the system changes greatly, the parameters of loop compensation cannot be applied.

[0004] Therefore, different loop compensations need to be designed for different battery-powered systems to make the flyback switching power supply applicable, which will undoubtedly result in duplication of work and increased costs. Utility Model Content

[0005] Based on this, it is necessary to provide a flyback switching power supply with strong applicability.

[0006] In a first aspect, the present application provides a flyback switching power supply, the flyback switching power supply comprising:

[0007] A voltage detection circuit, wherein the input end of the voltage detection circuit is used to connect to a power supply, and the voltage detection circuit is used to detect an input voltage;

[0008] A switching loop compensation circuit, wherein an input end of the switching loop compensation circuit is connected to an output end of the voltage detection circuit, and the switching loop compensation circuit is used to output an electrical signal matching a voltage detected by the voltage detection circuit;

[0009] A power management controller, wherein an input terminal of the power management controller is connected to an output terminal of the switching loop compensation circuit;

[0010] The switch circuit has a controlled end connected to a control end of a power management controller, an input end of the switch circuit is used to connect to a power supply, and an output end of the switch circuit is grounded.

[0011] In one embodiment, the voltage detection circuit includes:

[0012] The comparison circuit has an input end connected to a power supply, and an output end of the comparison circuit is connected to an input end of a switching loop compensation circuit.

[0013] In one embodiment, the comparison circuit includes:

[0014] A first voltage divider module, wherein an input end of the first voltage divider module is used to connect to a power supply;

[0015] A second voltage dividing module, wherein an input end of the second voltage dividing module is connected to a power supply end of the power management controller;

[0016] A first comparison module, wherein a first input terminal of the first comparison module is connected to an output terminal of the first voltage divider module, a second input terminal of the first comparison module is connected to an output terminal of the second voltage divider module, and an output terminal of the first comparison module is connected to an input terminal of the switching loop compensation circuit;

[0017] The second comparison module has a first input connected to the output of the first voltage divider module, a second input connected to the output of the second voltage divider module, and an output of the second comparison module connected to the input of the switching loop compensation circuit.

[0018] In one embodiment, the first comparison module is a hysteresis comparator or a single-limit comparator, and the second comparison module is a hysteresis comparator or a single-limit comparator.

[0019] In one embodiment, the second voltage dividing module includes:

[0020] A first adjustable resistor, wherein a first end of the first adjustable resistor is connected to a power supply end of the power management controller, and a second end of the first adjustable resistor is connected to a second input end of the first comparison module and a second input end of the second comparison module respectively;

[0021] A second adjustable resistor, wherein a first end of the second adjustable resistor is connected to a second end of the first adjustable resistor.

[0022] In one embodiment, the switching loop compensation circuit includes:

[0023] A plurality of loop compensation modules, wherein the output end of each loop compensation module is connected to the input end of the power management controller, and different loop compensation modules output different electrical signals;

[0024] A gating circuit, wherein the input end of the gating circuit is connected to the output end of the voltage detection circuit, the output end of the gating circuit is respectively connected to the input ends of multiple loop compensation modules, and the gating circuit is configured to select and turn on one of the loop compensation modules and the power management controller.

[0025] In one embodiment, the gating circuit includes a plurality of switch units, an input end of each switch unit is connected to an output end of the voltage detection circuit, and an output end of each switch unit is respectively connected to input ends of a plurality of loop compensation modules.

[0026] In one embodiment, the switch unit is composed of one or more of a relay, a MOS tube, a triode, and a NAND gate.

[0027] In one embodiment, the loop compensation module has a first end and a second end, and the loop compensation module includes a first resistor, a first capacitor, and a second capacitor;

[0028] The first resistor and the first capacitor are connected in series and then connected in parallel with the second capacitor between the first end and the second end of the loop compensation module.

[0029] In one embodiment, the flyback switching power supply further includes:

[0030] A filter circuit, wherein an input end of the filter circuit is used to connect to a power supply;

[0031] The absorption circuit has an input end connected to the output end of the filter circuit, the output end of the absorption circuit is used to connect the primary side of the flyback power transformer, and the ground end of the absorption circuit is connected to the input end of the switch circuit.

[0032] In a second aspect, the present application further provides a power supply device, the power supply device comprising:

[0033] Flyback power transformer;

[0034] Such as the flyback switching power supply in the above embodiment.

[0035] The above flyback switching power supply has at least the following beneficial effects:

[0036] By setting a voltage detection circuit and a switching loop compensation circuit, during the power-on process, the type of the power supply system is determined by detecting the input voltage, and based on the determination result, the compensation parameter corresponding to the input voltage is switched by the switching loop compensation circuit, so that the flyback switching power supply can maintain good dynamic response and stability regardless of the power supply system, thereby ensuring that the flyback switching power supply can be shared on a suitable development board, thereby saving R&D costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0038] Figure 1 is a schematic diagram of the structure of a flyback switching power supply in an embodiment;

[0039] Figure 2 is a schematic structural diagram of a flyback switching power supply in another embodiment;

[0040] Figure 3 is a schematic diagram of the structure of a comparison circuit in one embodiment;

[0041] Figure 4 is a schematic structural diagram of a flyback switching power supply in yet another embodiment;

[0042] Figure 5 FIG. 4 is a voltage transfer characteristic curve diagram of a hysteresis comparator in an embodiment. DETAILED DESCRIPTION

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] It can be understood that “at least one” means one or more, “plurality” means two or more, and “at least a portion of an element” means a part or all of an element.

[0048] 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.

[0049] As described in the background technology, for the internal battery power supply system of the car, the current mainstream power supply usually adopts 12V and 24V power supply systems. For the motor controller and motor driver, there are usually two ways to power the power supply: from the bus capacitor or from the car battery. Each power supply system will correspond to an auxiliary source design scheme; since the mainstream auxiliary source is converted from the battery to 5V, 12V, 16V, -7V, etc. through the flyback switching power supply to supply the positive and negative drive of the MCU, rotary transformer, operational amplifier, and power switch tube. When designing a flyback switching power supply, the transformer should be designed separately according to the power supply level of the battery, which undoubtedly increases the design cost. Secondly, for the flyback switching power supply, due to problems such as output load jump and input voltage fluctuation, there are strict requirements for the dynamic response and voltage accuracy of the flyback switching power supply. Usually, loop compensation is used to achieve good stability and dynamic response of the power supply under input voltage fluctuation and load mutation; and loop compensation is usually targeted, that is, it is only applicable to a specific system, so when the system changes greatly, the parameters of loop compensation cannot be applied.

[0050] It can be seen that designing different flyback switching power supplies for different battery-powered systems will result in duplication of work and cost control issues.

[0051] Based on the above reasons, the present application provides a flyback switching power supply, such as Figure 1 As shown, the flyback switching power supply includes a voltage detection circuit 2, a switching loop compensation circuit 4, a power management controller 6 and a switch circuit 8. The input end of the voltage detection circuit 2 is used to connect to the power supply 30, and the voltage detection circuit 2 is used to detect the input voltage; the input end of the switching loop compensation circuit 4 is connected to the output end of the voltage detection circuit 2, and the switching loop compensation circuit 4 is used to output an electrical signal matching the voltage detected by the voltage detection circuit 2; the input end of the power management controller 6 is connected to the output end of the switching loop compensation circuit 4; the controlled end of the switch circuit 8 is connected to the control end of the power management controller 6, the input end of the switch circuit 8 is used to connect to the power supply 30, and the output end of the switch circuit 8 is grounded.

[0052] Among them, the voltage detection circuit 2 is used to monitor the output voltage of the power supply to determine the size of the input voltage and provide data support for the subsequent regulation of the switching loop compensation circuit 4. The switching loop compensation circuit 4 is used to output an electrical signal that matches the voltage detected by the voltage detection circuit 2 to ensure the stability and response speed of the power supply system. The power management controller 6 is used to receive the electrical signals transmitted by the switching loop compensation circuit 4, and adjust the working state of the switch circuit 8 according to these electrical signals to maintain the stability of the output voltage.

[0053] Exemplarily, when the power supply 30 supplies power, the voltage detection circuit 2 detects the input voltage to determine the system of the power supply level (e.g., 12V or 24V) of the input voltage. After obtaining the judgment result, the loop compensation circuit 4 is switched to conduct the circuit that meets the loop compensation requirement of the input voltage, and outputs an electrical signal matching the input voltage, so that the power management controller 6 can adjust according to the received electrical signal, thereby ensuring that the flyback switching power supply still maintains good dynamic response and stability under the action of different input voltages.

[0054] The above-mentioned flyback switching power supply, by setting a voltage detection circuit 2 and a switching loop compensation circuit 4, determines the type of the power supply system by detecting the input voltage during the power-on process, and according to the judgment result, switches the loop compensation circuit 4 to turn on the circuit that meets the loop compensation requirements of the input voltage, so that the flyback switching power supply can still maintain good dynamic response and stability regardless of the power supply system, thereby ensuring that the flyback switching power supply can be shared on a suitable development board, thereby saving research and development costs.

[0055] In an exemplary embodiment, the voltage detection circuit 2 includes a comparison circuit. The input end of the comparison circuit is used to connect to the power supply 30 , and the output end of the comparison circuit is connected to the input end of the switching loop compensation circuit 4 .

[0056] The voltage detection circuit 2 can be a comparator or a proportional operational amplifier. The reference voltage connected to the comparison circuit can be a reference voltage generated by a voltage stabilizing chip or a power management controller 6. The comparison circuit has two controllable voltage thresholds. By detecting the input voltage, the type of power supply system corresponding to the input voltage can be determined; for example, when the input voltage reaches the threshold region of the 24V power supply system, the comparator output level will be reversed.

[0057] In this embodiment, the input voltage is detected by a comparison circuit, thereby completing the judgment of the type of the power supply system corresponding to the input voltage, and providing a specific implementation method for the voltage detection circuit 2 to realize input voltage detection.

[0058] In an exemplary embodiment, Figure 3 As shown, the comparison circuit includes a first voltage divider module 22, a second voltage divider module 24, a first comparison module 26, and a second comparison module 28. The input end of the first voltage divider module 22 is used to connect to the power supply 30; the input end of the second voltage divider module 24 is connected to the power supply end of the power management controller 6; the first input end of the first comparison module 26 is connected to the output end of the first voltage divider module 22, the second input end of the first comparison module 26 is connected to the output end of the second voltage divider module 24, and the output end of the first comparison module 26 is connected to the input end of the switching loop compensation circuit 4; the first input end of the second comparison module 28 is connected to the output end of the first voltage divider module 22, the second input end of the second comparison module 28 is connected to the output end of the second voltage divider module 24, and the output end of the second comparison module 28 is connected to the input end of the switching loop compensation circuit 4.

[0059] The first voltage divider module 22 and the second voltage divider module 24 may both refer to voltage divider circuits based on the resistor voltage divider principle. It should be noted that the first voltage divider module 22 is used to divide the input voltage to prevent the input voltage from being too large to damage the first comparison module 26 and the second comparison module 28; and the second voltage divider module 24 is used to adjust the reference voltage input to the first comparison module 26 and the second comparison module 28.

[0060] Exemplarily, the input voltage output from the power supply 30 is divided by the first voltage divider module 22 and then input to the first input terminal of the first comparison module 26 and the first input terminal of the second comparison module 28 respectively; and the standard voltage output from the power management controller 6 is adjusted by the second voltage divider module 24 and then input to the second input terminal of the first comparison module 26 and the second input terminal of the second comparison module 28 respectively. The two comparison modules compare the voltages of their first input terminal and second input terminal respectively, and output the comparison results to the switching loop compensation circuit 4, so that the switching loop compensation circuit 4 adjusts the loop compensation parameters according to the comparison results received above.

[0061] In this embodiment, by setting the first comparison module 26 and the second comparison module 28 in the comparison circuit, the comparison circuit can at least meet the detection of two different input voltages, and setting the first voltage divider module 22 can avoid the voltage input to the first comparison module 26 and the second comparison module 28 being too large and damaging the circuit; setting the second voltage divider module 24 can adjust the reference voltage input to the comparison module to adapt to the detection of more different types of power supply systems.

[0062] In an exemplary embodiment, Figure 3 As shown, the first comparison module 26 is a hysteresis comparator or a single-limit comparator, and the second comparison module 28 is a hysteresis comparator or a single-limit comparator.

[0063] For example, the voltage transfer characteristic of the hysteresis comparator is as follows: Figure 5 As shown, refer to Figure 3 The comparison circuit structure diagram shown in FIG. n =U p have:

[0064] U T1 =u 29 ×R7 / (R6+R7)+0

[0065] U T2 =u 29 ×R7 / (R6+R7)+u7×R7 / (R6+R7)

[0066] Therefore, U T1 -U T2 =u7×R7 / (R6+R 7）

[0067] Among them, the meaning of each parameter in the above formula can be understood by those skilled in the art from Figure 3 and Figure 4 As you can see, I won’t go into details here.

[0068] From the above formula, we can know that the dividing point of U7 from high level to low level and from low level to high level has the difference of u7×R7 / (R6+R7)V. According to the above formulas, we can know that the reference voltage U 29 Due to the positive feedback of the integrated operational amplifier, the value U should be appropriately lowered during simulation. 29 For the single limit comparison circuit, the signal source is connected to the in-phase input terminal of the operational amplifier, and the comparison voltage is input from the reverse input terminal. According to the "virtual short" principle of the operational amplifier, we have

[0069] u - =u5=u 29

[0070] u + =u8=u 24

[0071] It can be seen that the input voltage can be detected by setting the first comparison module 26 and the second comparison module 28 as one of a hysteresis comparator and a single-limit comparator.

[0072] In this embodiment, a specific implementation manner is provided for the first comparison module 26 and the second comparison module 28.

[0073] In an exemplary embodiment, Figure 3As shown, the second voltage divider module 24 includes a first adjustable resistor R4 and a second adjustable resistor R5. The first end of the first adjustable resistor R4 is connected to the power supply end of the power management controller 6, and the second end of the first adjustable resistor R4 is connected to the second input end of the first comparison module 26 and the second input end of the second comparison module 28 respectively; the first end of the second adjustable resistor R5 is connected to the second end of the first adjustable resistor R4.

[0074] For example, Figure 3 As shown, the terminal "V voltage divider 24" is connected to the output voltage of the first voltage divider module 22 as the input voltage of the first comparison module 26 and the second comparison module 28, the terminal "7" is the output terminal of the first comparison module 26, and the terminal "11" is the output terminal of the second comparison module 28. By adjusting the resistance values ​​of the first adjustable resistor R4 and the second adjustable resistor R5, the size of the detection threshold voltage (i.e., the reference voltage input to the first comparison module 26 and the second comparison module 28) can be changed.

[0075] In this embodiment, the first adjustable resistor and the second adjustable resistor are provided to adjust the reference voltage input to the first comparison module 26 and the second comparison module 28, that is, to adjust the detection threshold voltage, so that the comparison circuit is suitable for different input voltage detections.

[0076] In an exemplary embodiment, Figure 2 As shown, the switching loop compensation circuit 4 includes a plurality of loop compensation modules 42 and a gating circuit 44. The output end of each loop compensation module 42 is connected to the input end of the power management controller 6, and different loop compensation modules 42 output different electrical signals; the input end of the gating circuit 44 is connected to the output end of the voltage detection circuit 2, and the output end of the gating circuit 44 is respectively connected to the input ends of the plurality of loop compensation modules 42, and the gating circuit 44 is configured to select and conduct one of the loop compensation modules 42 and the power management controller 6.

[0077] For example, in order to achieve good stability and dynamic response of the power supply, different compensation needs to be provided to its power management loop when the input voltage is different. In the embodiment of the present application, different physical parameters of different loop compensation modules 42 (such as the composition or value of electronic components in the module) are different, so different compensation can be provided to the power management loop. Therefore, the difference in physical parameters between multiple loop compensation modules 42 can be utilized. According to the detection result (such as high level or low level) output by the voltage detection circuit 2, the selection circuit 44 selects to conduct a loop compensation module 42 and the power management controller 6 that match the detection result, so that the selected loop compensation module 42 is connected to the power management loop to match the loop compensation requirements under the current input voltage, thereby maintaining good stability and dynamic response of the power supply.

[0078] In this embodiment, a specific implementation method is provided for the switching loop compensation circuit 4.

[0079] In an exemplary embodiment, Figure 2 As shown, the gating circuit 44 includes a plurality of switch units, the input end of each switch unit is connected to the output end of the voltage detection circuit 2 , and the output end of each switch unit is respectively connected to the input ends of the plurality of loop compensation modules 42 .

[0080] Exemplarily, one switch unit is connected to and controls the on / off of one loop compensation module 42 . By setting a plurality of switch units, different loop compensation modules 42 can be selected to adapt to different input voltages and working conditions.

[0081] In an exemplary embodiment, the switch unit is composed of one or more of a relay, a MOS tube, a triode, and a NAND gate.

[0082] In an exemplary embodiment, Figure 2 As shown, the loop compensation module 42 has a first end and a second end, and the loop compensation module 42 includes a first resistor, a first capacitor and a second capacitor; the first resistor and the first capacitor are connected in series and then connected in parallel with the second capacitor between the first end and the second end of the loop compensation module 42.

[0083] It should be noted that, in addition to the above structure, the loop compensation module 42 can also be adaptively adjusted by those skilled in the art according to actual application requirements, such as adding electronic components such as compensation diodes or amplifiers, which will not be elaborated here.

[0084] In an exemplary embodiment, Figure 2 and Figure 4 As shown, the flyback switching power supply further includes a filter circuit 210 and an absorption circuit 12. The input end of the filter circuit 210 is used to connect to the power supply 30; the input end of the absorption circuit 12 is connected to the output end of the filter circuit 210, the output end of the absorption circuit 12 is used to connect to the primary side of the flyback power transformer 50, and the ground end of the absorption circuit 12 is connected to the input end of the switch circuit 8.

[0085] For example, the input voltage is filtered by the filter circuit 210, and the filter circuit 210 may refer to an RC filter circuit, which is used to remove high-frequency noise and ripple at the input end of the power supply 30 to ensure the stability of the power input. The absorption circuit 12 may refer to an RCD absorption circuit, which is used to absorb high-frequency noise and overvoltage in the circuit to protect other components in the circuit from damage. For example, in a flyback switching power supply, the absorption circuit 12 can absorb the peak voltage generated by the primary side of the transformer to prevent these voltages from interfering with other circuits.

[0086] In a second aspect, the present application further provides a power supply device, the power supply device comprising:

[0087] Flyback power transformer 50;

[0088] Such as the flyback switching power supply in the above embodiment.

[0089] The above power supply device, including the flyback switching power supply in the above embodiment, can be applied to different battery power supply systems.

[0090] 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.

[0091] 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.

[0092] 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 flyback switching power supply, characterized in that: The flyback switching power supply comprises: A voltage detection circuit, wherein the input end of the voltage detection circuit is used to connect to a power supply, and the voltage detection circuit is used to detect an input voltage; a switching loop compensation circuit, wherein an input end of the switching loop compensation circuit is connected to an output end of the voltage detection circuit, and the switching loop compensation circuit is used to output an electrical signal matching the voltage detected by the voltage detection circuit; A power management controller, wherein an input terminal of the power management controller is connected to an output terminal of the switching loop compensation circuit; A switch circuit, wherein a controlled end of the switch circuit is connected to a control end of the power management controller, an input end of the switch circuit is used to connect to the power supply, and an output end of the switch circuit is grounded.

2. The flyback switching power supply according to claim 1, characterized in that: The voltage detection circuit comprises: A comparison circuit, wherein the input end of the comparison circuit is used to connect to the power supply, and the output end of the comparison circuit is connected to the input end of the switching loop compensation circuit.

3. The flyback switching power supply according to claim 2, characterized in that: The comparison circuit comprises: A first voltage dividing module, wherein an input end of the first voltage dividing module is used to connect to the power supply; A second voltage dividing module, wherein an input end of the second voltage dividing module is connected to a power supply end of the power management controller; a first comparison module, wherein a first input end of the first comparison module is connected to an output end of the first voltage divider module, a second input end of the first comparison module is connected to an output end of the second voltage divider module, and an output end of the first comparison module is connected to an input end of the switching loop compensation circuit; A second comparison module, wherein a first input terminal of the second comparison module is connected to an output terminal of the first voltage divider module, a second input terminal of the second comparison module is connected to an output terminal of the second voltage divider module, and an output terminal of the second comparison module is connected to an input terminal of the switching loop compensation circuit.

4. The flyback switching power supply according to claim 3, characterized in that: The first comparison module is a hysteresis comparator or a single-limit comparator, and the second comparison module is a hysteresis comparator or a single-limit comparator.

5. The flyback switching power supply according to claim 3, characterized in that: The second voltage dividing module comprises: A first adjustable resistor, wherein a first end of the first adjustable resistor is connected to a power supply end of the power management controller, and a second end of the first adjustable resistor is respectively connected to a second input end of the first comparison module and a second input end of the second comparison module; A second adjustable resistor, wherein a first end of the second adjustable resistor is connected to a second end of the first adjustable resistor.

6. The flyback switching power supply according to claim 1, characterized in that: The switching loop compensation circuit comprises: A plurality of loop compensation modules, wherein the output end of each loop compensation module is connected to the input end of the power management controller, and different loop compensation modules output different electrical signals; A gating circuit, wherein the input end of the gating circuit is connected to the output end of the voltage detection circuit, the output end of the gating circuit is respectively connected to the input ends of multiple loop compensation modules, and the gating circuit is configured to select and turn on one of the loop compensation modules and the power management controller.

7. The flyback switching power supply according to claim 6, characterized in that: The gating circuit includes a plurality of switch units, the input end of each of the switch units is connected to the output end of the voltage detection circuit, and the output end of each of the switch units is respectively connected to the input ends of a plurality of the loop compensation modules.

8. The flyback switching power supply according to claim 7, characterized in that: The switch unit is composed of one or more of a relay, a MOS tube, a triode, and a NAND gate.

9. The flyback switching power supply according to claim 6, characterized in that: The loop compensation module has a first end and a second end, and the loop compensation module includes a first resistor, a first capacitor and a second capacitor; The first resistor and the first capacitor are connected in series and then connected in parallel with the second capacitor between the first end and the second end of the loop compensation module.

10. The flyback switching power supply according to claim 1, characterized in that: The flyback switching power supply also includes: A filter circuit, wherein an input end of the filter circuit is used to connect to a power supply; An absorption circuit, wherein the input end of the absorption circuit is connected to the output end of the filter circuit, the output end of the absorption circuit is used to connect to the primary side of the flyback power transformer, and the ground end of the absorption circuit is connected to the input end of the switch circuit.

11. A power supply device, characterized in that: The power supply device comprises: Flyback power transformer; A flyback switching power supply as claimed in any one of claims 1 to 10.

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