Circuit control method and apparatus therefor

Abstract

The application provides a circuit control method and a circuit control device thereof, which are applied to a hybrid flyback circuit. The method comprises the following steps: determining a collection time point according to the alternating time length of the conduction of a first MOS switch and a second MOS switch on the main side of the hybrid flyback circuit and a preset time coefficient; collecting a midpoint voltage between the first MOS switch and the second MOS switch according to the collection time point to obtain a first voltage signal; and adjusting a field excitation negative current in the hybrid flyback circuit according to a comparison result of the first voltage signal and a preset voltage value, so that the field excitation negative current meets the zero-voltage turn-on of a primary measurement switch of the hybrid flyback circuit.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of digital circuits, and in particular to a circuit control method and device thereof. BACKGROUND

[0002] In 2021, with the release of USB PD 3.1, the power range that USB PD can support is extended from 100W to 240W, which makes the application range of USB PD expand from the original communication devices (smartphones, tablets and laptops) to power tools, electric bicycles and industrial robots. The method used by USB PD 3.1 to achieve power enhancement is not to increase the output current but to increase the output voltage. Compared with USB PD 3.0 released in 2015, the output voltage range is expanded from the original 5V to 20V to 5V to 48V. The maximum output current is 5A. The Hybrid Flyback topology, as shown in Figure 1 , is very suitable for the application scenario of USB PD 3.1: on the one hand, the output voltage can be easily adjusted by adjusting the duty cycle; on the other hand, it has similar properties to the LLC topology, as shown in Figure 2 : it can achieve zero-voltage turn-on (ZVS) of the primary switch and zero-current turn-off (ZCS) of the secondary side synchronous rectifier. In addition, the topology mechanism is also very simple, with two primary switch tubes and one secondary side synchronous rectifier. The key to achieving high efficiency for the Hybrid Flyback topology is to ensure the realization of zero-voltage turn-on (ZVS) of the primary switch. The key to achieving zero-voltage turn-on (ZVS) is to ensure that the value of the magnetizing inductance current I val , as shown in Figure 3 , satisfies the following condition:

[0003]

[0004] where L m is the magnetizing inductance value of the transformer; C oss1 and C oss2 are the parasitic capacitances of the primary and secondary switch tubes, respectively; V bus is the output voltage of the PFC stage, that is, the bus voltage.

[0005] However, the excitation negative current value is not the larger the better, because the excessive excitation negative current, on the one hand, ensures the zero voltage switch (ZVS) of the primary measurement switch tube, and on the other hand, introduces additional conduction loss and transformer core loss, causing the efficiency to be reduced. Therefore, the current excitation negative current control method comprises: when S1 is turned on, detecting whether S1 realizes ZVS turn-on: (1) if S1 does not realize ZVS turn-on, the turn-on duration of S2 in the next cycle is increased by a duration Δt, so as to increase the excitation negative current, and thus after one or several switching cycles, S1 can realize ZVS; (2) if S1 realizes ZVS turn-on, the turn-on duration of S2 in the next cycle is reduced by a duration Δt, so as to reduce the excitation negative current, and thus after one or several switching cycles, S1 will lose the ZVS condition again. The system repeats the above two steps, and finally the excitation negative current can be controlled near the optimization point. However, this control method has defects, because the selection of Δt faces a dilemma: on the one hand, the larger the value of Δt, the faster the system can lock to the optimization point, but the final stable point deviates from the optimization point relatively larger, and the efficiency cannot be optimized; on the other hand, the smaller the value of Δt, the smaller the final design point deviates from the optimization point, and the efficiency deviates from the optimization point relatively smaller in the steady state, but at the same time, the adjustment speed is slow, and in the case of dynamic load, the system may be in adjustment all the time, the ZVS condition of S1 can never be reached, and the efficiency under dynamic load is poor. SUMMARY

[0006] The present application aims to provide a circuit control method and device, which can accurately control a target quantity at a desired set value through feedback control, so as to realize accurate control of the optimization point and achieve the purpose of optimizing efficiency.

[0007] To achieve the above purpose, the circuit control method provided by the present application is applied to a hybrid flyback circuit, and the method comprises: determining a collection time point according to the alternating duration of the turn-on of a first MOS switch and a second MOS switch of the main side of the hybrid flyback circuit and a preset time coefficient; collecting a midpoint voltage between the first MOS switch and the second MOS switch according to the collection time point to obtain a first voltage signal; and adjusting an excitation negative current in the hybrid flyback circuit according to the comparison result of the first voltage signal and a preset voltage value, so that the excitation negative current meets the zero voltage turn-on of the primary measurement switch of the hybrid flyback circuit.

[0008] In an embodiment of the present application, optionally, the determination of the acquisition time point according to the preset time coefficient and the alternate time length of the conduction of the first MOS switch and the second MOS switch of the main side of the hybrid flyback circuit comprises: obtaining a dead time according to the turn-off end time of the second MOS switch and the turn-on start time of the first MOS switch; and determining the acquisition time point according to the preset time coefficient and the dead time.

[0009] In an embodiment of the present application, optionally, the adjustment of the excitation negative current according to the comparison result of the first voltage signal and the preset voltage value comprises: generating a second voltage signal through a feedback compensation network circuit according to the comparison result of the voltage signal and the preset voltage value; and adjusting the excitation negative current by adjusting the conduction time length of the second MOS switch according to the second voltage signal.

[0010] In an embodiment of the present application, optionally, the adjustment of the excitation negative current according to the second voltage signal by adjusting the conduction time length of the second MOS switch comprises: adjusting the conduction time of the second MOS switch according to the second voltage signal, recording the conduction time length of the second MOS switch to generate a third voltage signal; and turning off the second MOS switch according to the comparison result of the second voltage signal and the third voltage signal.

[0011] In an embodiment of the present application, optionally, the adjustment of the conduction time of the second MOS switch according to the second voltage signal comprises: increasing the conduction time of the second MOS switch according to a preset rule when the first voltage signal is higher than the preset voltage value; and decreasing the conduction time of the second MOS switch according to a preset rule when the first voltage signal is lower than the preset voltage value.

[0012] In an embodiment of the present application, optionally, the acquisition of the first voltage signal according to the acquisition of the midpoint voltage between the first MOS switch and the second MOS switch at the acquisition time point comprises: acquiring the equivalent voltage of the midpoint voltage between the first MOS switch and the second MOS switch through the auxiliary winding of the transformer of the hybrid flyback circuit at the acquisition time point to obtain the first voltage signal.

[0013] The present application further provides a circuit control device applied to a hybrid flyback circuit, comprising a calculation module and a feedback compensation network module; wherein the calculation module is configured to determine an acquisition time point according to the preset time coefficient and the alternate time length of the conduction of the first MOS switch and the second MOS switch of the main side of the hybrid flyback circuit; the feedback compensation network module is configured to acquire a first voltage signal according to the acquisition of the midpoint voltage between the first MOS switch and the second MOS switch at the acquisition time point; and adjust an excitation negative current according to the comparison result of the first voltage signal and a preset voltage value, so that the excitation negative current satisfies the zero-voltage turn-on of the primary measurement switch of the hybrid flyback circuit.

[0014] In an embodiment of the present application, optionally, the feedback compensation network module comprises a sampling unit, a feedback compensation unit and an adjusting unit; the sampling unit is configured to obtain a first voltage signal according to a midpoint voltage between the first MOS switch and the second MOS switch at the collection time point; the feedback compensation unit is configured to generate a second voltage signal according to a comparison result of the voltage signal and a preset voltage value; and the adjusting unit is configured to adjust the on duration of the second MOS switch according to the second voltage signal.

[0015] In an embodiment of the present application, optionally, the adjusting unit comprises a comparator and an on timer; the on timer is configured to record the on duration of the second MOS switch to generate a third voltage signal; and the comparator is configured to turn off the second MOS switch according to a comparison result of the second voltage signal and the third voltage signal.

[0016] In an embodiment of the present application, optionally, the sampling unit is configured to obtain the first voltage signal by collecting an equivalent voltage of the midpoint voltage between the first MOS switch and the second MOS switch through an auxiliary winding of a transformer of the hybrid flyback circuit.

[0017] The present application has the beneficial technical effects that: the size of the excitation negative current is set by adjusting the preset voltage value and the preset time coefficient, so as to realize efficiency optimization, and the stability of the excitation negative current set value under dynamic load is ensured by setting the frequency response characteristic of the compensation network. Quasi-ZVS (Quasi-ZVS) can be realized, that is, when the first MOS switch is turned on, the midpoint voltage is not 0 but a value close to 0, and at the same time, the excitation negative current is also reduced, the on-state loss and the transformer core loss are reduced, so as to obtain a more optimal comprehensive efficiency.

[0018] In order to make the above and other objects, features and advantages of the present application more apparent, the following will describe embodiments of the present application, and the accompanying drawings will be described in detail as follows. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0020] Figure 1 It is a structural schematic diagram of a common hybrid flyback circuit topology;

[0021] Figure 2 It is a structural schematic diagram of a common LLC topology;

[0022] Figure 3 A schematic diagram of the relationship between the excitation negative current and the zero voltage turn-on;

[0023] Figure 4 A flowchart of the circuit control method provided by an embodiment of the present application;

[0024] Figure 5 A flowchart of the adjustment of the excitation negative current provided by an embodiment of the present application;

[0025] Figure 6 A flowchart of the adjustment of the on-time of the second MOS switch provided by an embodiment of the present application;

[0026] Figure 7 A schematic diagram of the principle structure of the circuit control device provided by an embodiment of the present application;

[0027] Figure 8 A schematic diagram of the application logic of the circuit control device provided by an embodiment of the present application. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0029] Specific embodiments of the present application are disclosed in detail below with reference to the following description and drawings. The principles of the present application can be employed in any manner without departing from the spirit of the application. It should be understood that the embodiments of the present application are not limited in scope to the embodiments described. The embodiments of the present application include all changes, modifications and equivalents coming within the spirit and scope of the appended claims.

[0030] Features described and / or illustrated with respect to one embodiment can be used in the same or similar manner in one or more other embodiments, in combination with other features in other embodiments, or in place of other features in other embodiments.

[0031] It should be emphasized that the term "comprises / comprising" when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof. Figure 4 As shown, the circuit control method provided by the present application is applied to a hybrid flyback circuit, and the method comprises:

[0032] S401 determining a collection time point according to the preset time coefficient and the on-off alternate time length of the first MOS switch and the second MOS switch of the main side of the hybrid flyback circuit;

[0033] S402 acquiring a first voltage signal according to a midpoint voltage between the first MOS switch and the second MOS switch at the acquisition time point;

[0034] S403 adjusting the excitation negative current according to a comparison result of the first voltage signal and a preset voltage value, so that the excitation negative current meets the zero-voltage turn-on of the primary measurement switch of the hybrid flyback circuit.

[0035] In an embodiment of the present application, optionally, the acquisition time point is determined according to the alternate time length of the turn-on of the first MOS switch and the second MOS switch of the main side of the hybrid flyback circuit and a preset time coefficient, and the acquisition time point includes: obtaining a dead time according to the turn-off end time of the second MOS switch and the turn-on start time of the first MOS switch; and determining the acquisition time point according to the preset time coefficient and the dead time.

[0036] Specifically, in actual work, the time period from the turn-off of the second MOS switch to the turn-on of the first MOS switch is the dead time, which is the alternate time length described above. Based on the dead time and the preset time coefficient, a specific time point can be located, for example, the dead time is A, and the preset time coefficient is 0.5. At this time, the acquisition time point is 0.5A. If A is 1 minute, the acquisition time point is the 30th second after the turn-off of the second MOS switch. Then, the midpoint voltage is collected according to the time point in the above step S502.

[0037] The preset time coefficient can be set by the staff according to actual needs, which is essentially a coefficient less than 1, and the purpose is to determine the specific sampling time point in the dead time, and the sampling time point can be any time in the dead time, which is not limited in the present application.

[0038] After the first voltage signal is collected based on the above sampling time point, the adjustment scheme can be determined using the first voltage signal. Specifically, please refer to Figure 5 In an embodiment of the present application, adjusting the excitation negative current according to the comparison result of the first voltage signal and the preset voltage value can include:

[0039] S501 generating a second voltage signal through a feedback compensation network circuit according to the comparison result;

[0040] S502 adjusting the excitation negative current by adjusting the turn-on time length of the second MOS switch according to the second voltage signal.

[0041] The adjusting the on-time of the second MOS switch according to the second voltage signal can include: increasing the on-time of the second MOS switch according to a preset rule when the first voltage signal is higher than a preset voltage value; and decreasing the on-time of the second MOS switch according to the preset rule when the first voltage signal is lower than the preset voltage value. In this embodiment, the principle of adjusting the excitation negative current by the on-time of the second MOS switch is that: when the on-time of the second MOS switch is lengthened, the excitation negative current is increased, and finally the falling speed of the midpoint voltage is increased, and the voltage value of the midpoint voltage VH at the sampling time point is reduced; when the on-time of the second MOS switch is shortened, the excitation negative current is reduced, and finally the falling speed of the midpoint voltage is slowed down, and the voltage value of the midpoint voltage VH at the sampling time point is increased. Specifically, in actual work, the preset rule can be established according to the corresponding relationship between the on-time of the second MOS switch and the excitation negative current; for example, when the on-time of the second MOS switch is A, the excitation negative current is increased by B, and when the on-time of the second MOS switch is increased by A1, the excitation negative current is increased by B1, at this time, when the first voltage signal is less than the preset voltage value, the difference C between the first voltage signal and the preset voltage value can be calculated, and according to the multiple relationship between C and B1, A1 corresponding to the multiple is added to A to realize that the first voltage signal is close to or equal to the preset voltage value; similarly, the on-time of the second MOS switch can also be analyzed, that is, when the on-time of the second MOS switch is decreased by A2, the excitation negative current is decreased by B2, and when the first voltage signal is greater than the preset voltage value, the on-time of B2 corresponding to the multiple can be reduced in the similar way. Therefore, the size of the excitation negative current is set by adjusting the preset voltage value and the preset time coefficient, so that the overall working efficiency of the hybrid flyback circuit is optimized by zero-voltage turn-on.

[0042] For the adjustment mode of the on-time of the second MOS switch, please refer to Figure 6 In an embodiment of the present application, the adjusting the excitation negative current by adjusting the on-time of the second MOS switch according to the second voltage signal can include:

[0043] S601 adjusting the on-time of the second MOS switch according to the second voltage signal, and recording the on-time of the second MOS switch to generate a third voltage signal;

[0044] S602 turning off the second MOS switch according to the comparison result of the second voltage signal and the third voltage signal.

[0045] Specifically, in actual work, the second voltage signal is used to set the on time of the second MOS switch, and the third voltage signal gradually increases with the increase of the on duration of the second MOS switch; until the second voltage signal and the third voltage signal are equal, which represents that the second MOS switch completes the set on time, at which time the second MOS switch can be turned off.

[0046] To avoid using high-voltage sampling devices and reduce costs, in an embodiment of the present application, obtaining the first voltage signal according to the midpoint voltage between the first MOS switch and the second MOS switch at the collection time point can include: obtaining the first voltage signal according to the midpoint voltage between the first MOS switch and the second MOS switch through the auxiliary winding of the transformer of the hybrid flyback circuit at the collection time point. The specific structure can refer to the auxiliary winding structure of the transformer in the prior art, which functions to avoid using high-voltage sampling devices through the measurement of equivalent voltage; since the structure forms are various, they will not be exemplified one by one here.

[0047] Please refer to Figure 7 The present application also provides a circuit control device applied to a hybrid flyback circuit, which includes a calculation module and a feedback compensation network module; the calculation module is used to determine a collection time point according to the alternate time of the on of the first MOS switch and the second MOS switch of the main side of the hybrid flyback circuit and a preset time coefficient; the feedback compensation network module is used to obtain a first voltage signal according to the midpoint voltage between the first MOS switch and the second MOS switch at the collection time point; and adjust the excitation negative current according to the comparison result of the first voltage signal and a preset voltage value, so that the excitation negative current meets the zero-voltage turn-on of the primary measurement switch of the hybrid flyback circuit.

[0048] In the above embodiment, the feedback compensation network module includes a sampling unit, a feedback compensation unit and an adjusting unit; the sampling unit is used to obtain a first voltage signal according to the midpoint voltage between the first MOS switch and the second MOS switch at the collection time point; the feedback compensation unit is used to generate a second voltage signal according to the comparison result of the voltage signal and a preset voltage value; and the adjusting unit is used to adjust the on time of the second MOS switch according to the second voltage signal. The adjusting unit includes a comparator and an on timer; the on timer is used to record the on time of the second MOS switch to generate a third voltage signal; and the comparator is used to turn off the second MOS switch according to the comparison result of the second voltage signal and the third voltage signal. In actual work, the comparator and the on timer can be electrically connected to transmit the voltage signals; it should be noted that the present application does not limit the direct connection of the comparator and the on timer, and the related personnel in the field can select and set according to actual needs.

[0049] To facilitate a clearer understanding of the specific application methods and principles of the circuit control device provided in this application, please refer to the following: Figure 8 As shown.

[0050] Sampling before S1 is activated (K) v ×V H And maintain the midpoint voltage V H The voltage signal (sample and hold S / H) is input to the inverting input of a feedback compensation network circuit, and a reference voltage V is input to it. ref The signal is connected to the positive input terminal of the feedback compensation network circuit. Through the feedback compensation network circuit, a voltage signal is generated, which is used to set the conduction time of S2. There is also a conduction timing unit, namely the S2 conduction timing unit, which records the conduction time of S2 and generates a voltage signal indicating the conduction time of S2. This voltage signal and the voltage signal used to set the conduction time of S2 are simultaneously input to a comparator for comparison. When the voltage signal indicating the conduction time of S2 is equal to the voltage signal setting the conduction time of S2, S2 is turned off. The principle is as follows: from the time S2 is turned off until a certain moment before S1 is turned on (for example, K after S2 is turned off...),... d ×t dead Time, where: t dead The dead time from the shutdown of S2 to the activation of S1, K d (A coefficient less than 1), sampling the midpoint voltage V at this moment. H Check the voltage value and see if the current voltage value is equal to our set value V. ref If the sampled value at this moment is higher than the set value, the voltage signal at the turn-on time of S2 will increase through the feedback network, and the turn-on duration of S2 in the next cycle will increase accordingly, thereby increasing the excitation negative current. Ultimately, this can accelerate the decrease rate of the midpoint voltage and reduce the midpoint voltage V at the sampling time. H The voltage value; if the sampled value at this moment is lower than the set value, the voltage signal at the turn-on time of S2 will decrease through the feedback network, and the turn-on time of S2 in the next cycle will be shortened, thereby reducing the excitation negative current. Ultimately, this can slow down the rate of decrease of the midpoint voltage and increase the midpoint voltage V at the sampling time. H The voltage value. Through the design of the feedback network, the sampled value can be accurately set to the set value. Since there is a certain time between the sampling time and the turn-on time of S1, the length of this time can be reasonably set (adjusting K). d and reference voltage V ref This enables zero-voltage turn-on (ZVS) of S1; by setting the frequency response characteristics of the compensation network, the stability of the excitation negative current setting value under dynamic load conditions is ensured.

[0051] In practical application, the circuit control method and the device thereof provided by the application can also realize quasi-ZVS (Quasi-ZVS), that is, when the first MOS switch is turned on, the voltage value of the midpoint voltage VH is not limited to 0, but can be a value close to 0. Although this will bring about a turn-on loss, it also reduces the excitation negative current, thereby reducing the on-state loss and the transformer core loss, and thus obtaining a better comprehensive efficiency.

[0052] The application has the beneficial technical effects that: the size of the excitation negative current is set by adjusting the preset voltage value and the preset time coefficient, thereby realizing efficiency optimization, and the stability of the excitation negative current set value under a dynamic load condition is ensured by setting the frequency response characteristic of the compensation network. Quasi-ZVS (Quasi-ZVS) can be realized, that is, when the first MOS switch is turned on, the voltage value of the midpoint voltage is not limited to 0, but can be a value close to 0. Meanwhile, the excitation negative current is also reduced, the on-state loss and the transformer core loss are reduced, and thus a better comprehensive efficiency is obtained.

[0053] It should be noted that, in this document, the terms such as first and second are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such a process, method, article or device. Without more limitations, the element defined by the statement "including a" does not exclude the presence of another identical element in the process, method, article or device including the element. The terms "upper", "lower" and the like indicate the orientation or positional relationship shown in the drawings, and are only used for the convenience of describing the application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application. Unless otherwise specified and limited, the terms "mount", "connect", "connect" should be understood broadly, for example, it can be a fixed connection, or a detachable connection, or an integral connection; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or a communication between two elements. For those skilled in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances.

[0054] The various embodiments in the specification are described in progressive manner, and the same or similar parts among the various embodiments can be referred to each other. Each embodiment focuses on the difference from other embodiments. In the description of the specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the embodiments of the specification. The illustrative description of the above terms in the specification does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the specification and the features of the different embodiments or examples without contradiction.

[0055] The principles and implementation manners of the present application are described in the specific embodiments in the present application. The above embodiment description is only for helping to understand the method of the present application and its core idea. Meanwhile, for the person skilled in the art, the specific implementation manners and application ranges will be changed according to the idea of the present application. In summary, the content of the specification should not be understood as the limitation of the present application.

Claims

1. A circuit control method applied to a hybrid flyback circuit, characterized in that, The method comprises: According to the preset time coefficient and the alternate time length of the conduction of the first MOS switch and the second MOS switch of the main side of the hybrid flyback circuit, a collection time point is determined; According to the collection time point, a midpoint voltage between the first MOS switch and the second MOS switch is collected, and a first voltage signal is obtained; According to the comparison result of the first voltage signal and a preset voltage value, the excitation negative current in the hybrid flyback circuit is adjusted, so that the excitation negative current meets the zero-voltage opening of the primary measurement switch of the hybrid flyback circuit; According to the preset time coefficient and the alternate time length of the conduction of the first MOS switch and the second MOS switch of the main side of the hybrid flyback circuit, a collection time point is determined, comprising: According to the second MOS switch off end time and the first MOS switch on start time, a dead time is obtained; According to the preset time coefficient and the dead time, the collection time point is determined; According to the comparison result, a second voltage signal is generated through a feedback compensation network circuit; According to the second voltage signal, the excitation negative current is adjusted by adjusting the conduction time length of the second MOS switch. According to the second voltage signal, the excitation negative current is adjusted by adjusting the conduction time length of the second MOS switch, comprising:

2. The circuit control method according to claim 1, characterized by, According to the second voltage signal, the conduction time of the second MOS switch is adjusted, and a third voltage signal is generated by recording the conduction time length of the second MOS switch; According to the comparison result of the second voltage signal and the third voltage signal, the second MOS switch is turned off. According to the second voltage signal, the conduction time of the second MOS switch is adjusted, comprising:

3. The circuit control method according to claim 2, characterized by, When the first voltage signal is higher than the preset voltage value, the conduction time of the second MOS switch is increased according to a preset rule; When the first voltage signal is lower than the preset voltage value, the conduction time of the second MOS switch is decreased according to the preset rule. According to the collection time point, the equivalent voltage of the midpoint voltage between the first MOS switch and the second MOS switch is collected through the auxiliary winding of the transformer of the hybrid flyback circuit, and the first voltage signal is obtained.

4. The circuit control method according to claim 1, characterized by, The circuit control device comprises a calculation module and a feedback compensation network module; wherein, The calculation module is used for determining the collection time point according to the preset time coefficient and the alternate time length of the conduction of the first MOS switch and the second MOS switch of the main side of the hybrid flyback circuit, comprising: obtaining the dead time according to the second MOS switch off end time and the first MOS switch on start time; and determining the collection time point according to the preset time coefficient and the dead time; 5. A circuit control device applied to a hybrid flyback circuit, characterized in that, The calculation module is used for determining the collection time point according to the preset time coefficient and the alternate time length of the conduction of the first MOS switch and the second MOS switch of the main side of the hybrid flyback circuit, comprising: obtaining the dead time according to the second MOS switch off end time and the first MOS switch on start time; and determining the collection time point according to the preset time coefficient and the dead time; ​ The feedback compensation network module is configured to obtain a first voltage signal according to a midpoint voltage between the first MOS switch and the second MOS switch at the collection time point; and adjust the negative excitation current according to a comparison result of the first voltage signal and a preset voltage value, so that the negative excitation current satisfies zero voltage turn-on of a primary measurement switch of the hybrid flyback circuit. The feedback compensation network module comprises a sampling unit, a feedback compensation unit and an adjusting unit. The sampling unit is configured to obtain a first voltage signal according to a midpoint voltage between the first MOS switch and the second MOS switch at the collection time point. The feedback compensation unit is configured to generate a second voltage signal according to a comparison result of the voltage signal and a preset voltage value. The adjusting unit is configured to adjust a turn-on duration of the second MOS switch according to the second voltage signal.

6. The circuit control device according to claim 5, characterized in that The adjusting unit comprises a comparator and a turn-on timer. The turn-on timer is configured to record the turn-on duration of the second MOS switch to generate a third voltage signal. The comparator is configured to turn off the second MOS switch according to a comparison result of the second voltage signal and the third voltage signal.

7. The circuit control device according to claim 5, characterized in that The sampling unit is configured to obtain a first voltage signal by collecting an equivalent voltage of a midpoint voltage between the first MOS switch and the second MOS switch through an auxiliary winding of a transformer of the hybrid flyback circuit.

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