Control method and control system of switching power supply

Abstract

The invention discloses a control method and a control system of a switching power supply, and belongs to the field of switching power supplies. The control method of the switching power supply comprises the following steps: in a feedback regulation mode, controlling a target switching tube to be conducted for a target duration at a target moment and obtaining a target drain terminal voltage after the target switching tube is turned off; based on the target drain terminal voltage and a target voltage range, determining a target duration corresponding to the next conduction of the target switch tube until the target drain terminal voltage is within the target voltage range; the target voltage range is determined based on the target switch tube. According to the control method of the switching power supply, the actual effect of zero-voltage conduction control can be adaptively adjusted, the precision and reliability of zero-voltage conduction control are improved, and the loss of the switching power supply is reduced.

Description

Technical Field

[0001] The present application relates to the field of switching power supplies, and in particular to a control method and control system for a switching power supply. Background Art

[0002] Switching converters operating in discontinuous-current mode (DCM) experience free resonance when the primary and secondary switches are off, due to the magnetizing inductance and equivalent capacitance of the switch node to ground. To reduce switching losses when the primary switch is on, conventional schemes control the primary switch to conduct at the lowest point of the resonant voltage (conduction valley), a quasi-resonant approach. While this quasi-resonant approach can reduce the drain-source voltage at the time the primary switch is turned on, as the transformer input voltage increases or the number of conduction valleys of the primary switch resonant voltage increases, the drain-source voltage of the quasi-resonant switching converter remains high at the time the primary switch is turned on. This leads to higher switching losses and, consequently, lower system efficiency.

[0003] In the related art, a zero-voltage turn-on switching converter has been proposed for quasi-resonant switching converters. This converter injects energy into the resonant unit by controlling the switching on of a specific switch tube for an appropriate time at a specific moment in the free resonance phase to increase the resonance amplitude and reduce the valley of the primary resonant voltage to zero volts, thereby achieving zero-voltage turn-on of the primary switch tube and reducing switching losses. However, in actual circuits, the length of the compensation on-time is affected by many factors, such as the input voltage, output voltage, the number of system conduction valleys, system design parameters, and PCB parasitic parameters. In other words, the optimal compensation on-time varies with these many parameters. Therefore, in actual circuits, the optimal compensation on-time is difficult to accurately obtain, resulting in poor zero-voltage turn-on effect. Summary of the Invention

[0004] This application aims to address at least one of the technical problems existing in the related art. To this end, this application proposes a control method and control system for a switching power supply that can adaptively adjust the actual effect of zero-voltage turn-on control, improve the accuracy and reliability of zero-voltage turn-on control, thereby further reducing switching power supply losses and improving system efficiency.

[0005] In a first aspect, the present application provides a method for controlling a switching power supply, the switching power supply comprising a transformer, a primary switching tube connected to the primary side of the transformer, and a freewheeling switching tube connected to the secondary side of the transformer; the method comprising:

[0006] In the feedback regulation mode, after controlling the target switch tube to be turned on for a target period of time and then turned off at a target time, a target drain terminal voltage is obtained; the target drain terminal voltage is the voltage at the first resonance valley bottom that appears after the drain terminal voltage of the primary side switch tube recovers to a free resonance state after the target switch tube is turned off, or the voltage at the first resonance valley top that appears after the drain terminal voltage of the freewheeling switch tube recovers to a free resonance state; the target switch tube is the freewheeling switch tube or a compensation switch tube connected between the primary side switch tube and ground; the target time and the target drain terminal voltage are determined based on the target switch tube;

[0007] Based on the target drain voltage and the target voltage range, the target duration corresponding to the next turn-on of the target switch tube is determined until the target drain voltage is within the target voltage range; when the target switch tube is the compensation switch tube, the target voltage range is a voltage within a first preset range close to 0; when the target switch tube is the freewheeling switch tube, the target voltage range is a voltage within a second preset range close to the platform voltage of the freewheeling switch tube.

[0008] According to the control method of the switching power supply of the present application, by controlling the target switch tube to be turned on for a target duration and then turned off at a target time in a feedback regulation mode, obtaining the target drain voltage corresponding to the primary switch tube or the freewheeling switch tube, and determining the target duration corresponding to the next turn-on of the target switch tube based on the target drain voltage and the target voltage range, until the target drain voltage is within the target voltage range, the zero voltage turn-on effect represented by the comparison result of the target drain voltage and the target voltage range can be achieved, and the target duration is adjusted so that the adjusted target duration is used for the next zero voltage turn-on, thereby reducing the gap between the next target drain voltage and the target voltage range and improving the zero voltage turn-on effect. In this cycle, the target duration is adaptively adjusted during the operation of the switching power supply, thereby adaptively adjusting the actual effect of the zero voltage turn-on control, improving the accuracy and reliability of the zero voltage turn-on control, thereby further reducing the loss of the switching power supply and improving the system efficiency.

[0009] In a second aspect, the present application provides a control system for a switching power supply, comprising:

[0010] transformer;

[0011] A primary switching tube connected to the primary side of the transformer;

[0012] A freewheeling switch connected to the secondary side of the transformer;

[0013] a primary switch controller connected to the primary switch tube and configured to control the on / off state of the primary switch tube based on a drain terminal voltage signal of the primary switch tube;

[0014] A secondary side switch controller, connected to the freewheeling switch tube, for freewheeling conduction control of the switching power supply;

[0015] The secondary side switch controller is further configured to control the on / off state of the freewheeling switch based on the target time and the target duration; and is further configured to, in the compensation conduction mode, determine the target duration as the target duration corresponding to the next turn-on of the freewheeling switch; and, in the feedback regulation mode, adjust the target duration based on the target drain voltage and the target voltage range, and determine the adjusted target duration as the target duration corresponding to the next turn-on of the freewheeling switch.

[0016] In the case where a compensation switch tube is connected between the primary switch tube and the ground, the primary switch controller is further used to control the on / off state of the compensation switch tube based on the target time and the target duration; and is further used to, in the compensation conduction mode, determine the target duration as the target duration corresponding to the next time the compensation switch tube is turned on; in the feedback regulation mode, adjust the target duration based on the target drain voltage and the target voltage range, and determine the adjusted target duration as the target duration corresponding to the next time the compensation switch tube is turned on.

[0017] According to the control system of the switching power supply of the present application, by setting a transformer, a primary switch tube connected to the primary side of the transformer, a freewheeling switch tube connected to the secondary side of the transformer, a primary switch controller connected to the primary switch tube and a secondary switch controller connected to the freewheeling switch tube, and a compensation switch tube connected between the primary switch tube and the ground, it is possible to control the on-off state of the target switch tube based on the target time and target duration, and control the on-off state of the primary switch tube based on the drain voltage signal of the primary switch tube, thereby realizing a compensation conduction mode for achieving zero voltage conduction, and for adjusting the target The duration is used to adjust the feedback regulation mode of the zero voltage turn-on effect, so that in the actual execution process, the compensation conduction mode and the feedback regulation mode can be alternately performed at a certain time interval to achieve adaptive adjustment of the target duration, thereby achieving adaptive adjustment of the zero voltage turn-on effect, improving the accuracy and reliability of zero voltage turn-on control, thereby further reducing the switching power supply loss and improving the system efficiency; and by multiplexing the on-off state of the freewheeling switch tube to achieve zero voltage turn-on control, the compatibility and adaptability of the zero voltage turn-on control can be improved, and there is no need to design a complex controller, saving design costs.

[0018] In a third aspect, the present application provides a chip comprising a processor and a communication interface, wherein the communication interface is coupled to the processor, and the processor is configured to run a program or instruction to implement the switching power supply control method as described in the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0020] Figure 1 1 is a flow chart of a method for controlling a switching power supply provided in an embodiment of the present application;

[0021] Figure 2 This is one of the schematic diagrams of the results of the switching power supply control method provided in an embodiment of the present application;

[0022] Figure 3 This is the second schematic diagram of the result of the control method of the switching power supply provided by the embodiment of the present application;

[0023] Figure 4 This is one of the structural diagrams of the control system of the switching power supply provided in the embodiment of the present application;

[0024] Figure 5 This is the second structural diagram of the control system of the switching power supply provided in the embodiment of the present application;

[0025] Figure 6 This is the third structural diagram of the control system of the switching power supply provided in the embodiment of the present application;

[0026] Figure 7 This is the fourth structural diagram of the control system of the switching power supply provided in the embodiment of the present application;

[0027] Figure 8 This is the fifth structural diagram of the control system of the switching power supply provided in the embodiment of the present application;

[0028] Figure 9 This is the sixth structural diagram of the control system of the switching power supply provided in the embodiment of the present application;

[0029] Figure 10 This is the seventh structural diagram of the control system of the switching power supply provided in the embodiment of the present application;

[0030] Figure 11 This is the eighth structural diagram of the control system of the switching power supply provided in the embodiment of the present application;

[0031] Figure 12 This is the ninth structural diagram of the control system of the switching power supply provided in the embodiment of the present application;

[0032] Figure 13 This is the tenth structural diagram of the control system of the switching power supply provided in the embodiment of the present application;

[0033] Figure 14This is the eleventh structural diagram of the control system of the switching power supply provided in the embodiment of the present application;

[0034] Figure 15 This is the twelfth structural diagram of the control system of the switching power supply provided in the embodiment of the present application;

[0035] Figure 16 This is a schematic diagram of the results of the switching power supply control method provided by an embodiment of the present application;

[0036] Figure 17 This is one of the structural diagrams of a control system of another switching power supply provided in an embodiment of the present application;

[0037] Figure 18 This is a second structural diagram of a control system of another switching power supply provided in an embodiment of the present application;

[0038] Figure 19 This is a schematic diagram of the results of another switching power supply control method provided by an embodiment of the present application;

[0039] Figure 20 It is a structural diagram of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0040] The following will be combined with the accompanying drawings in the embodiments of the present application to clearly describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of this application.

[0041] The terms "first," "second," and the like in the specification and claims of this application are used to distinguish similar objects, and are not used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of this application can be implemented in an order other than that illustrated or described herein, and that the objects distinguished by "first," "second," and the like are generally of the same type, and do not limit the number of objects; for example, the first object can be one or more. In addition, the term "and / or" in the specification and claims refers to at least one of the connected objects, and the character " / " generally indicates that the objects connected are in an "or" relationship.

[0042] The control method, control system, electronic device and readable storage medium of the switching power supply provided by the embodiments of the present application are described in detail below with reference to the accompanying drawings through specific embodiments and their application scenarios.

[0043] The control method of the switching power supply may be applied to a terminal, and may be specifically executed by hardware or software in the terminal.

[0044] The terminal includes but is not limited to portable communication devices such as mobile phones or tablet computers. It should also be understood that in some embodiments, the terminal may not be a portable communication device, but a desktop computer.

[0045] The control method of the switching power supply provided in the embodiment of the present application can be executed by the switching power supply or a functional module or functional entity in the switching power supply that can implement the control method of the switching power supply. The control method of the switching power supply provided in the embodiment of the present application is described below using the switching power supply as an example of the execution entity.

[0046] like Figure 1 As shown, the control method of the switching power supply includes: step 110, step 120 and step 130.

[0047] The switching power supply includes a transformer, a primary switching tube connected to the primary side of the transformer, and a freewheeling switching tube connected to the secondary side of the transformer.

[0048] like Figure 11 As shown, in some embodiments, the switching power supply may include a primary switch controller connected to the primary switch tube QP, and a secondary switch controller connected to the freewheeling switch tube QS.

[0049] like Figure 11 As shown in the figure, in actual implementation, the AC input voltage Vac is rectified by the rectifier bridge, forming the voltage VBULK on the input capacitor CBULK. The primary switch controller controls the conduction and shutdown of the primary power transistor (primary switch) QP based on the output power demand through the drive control signal, achieving the excitation and demagnetization of the transformer, thereby coupling the energy in the input capacitor CBULK to the secondary side of the transformer NS through the primary side of the transformer NP. The secondary switch controller efficiently transfers the energy coupled to the secondary side of the transformer to the output capacitor COUT by controlling the conduction and shutdown of the secondary power transistor (freewheeling switch) QS, and outputs the target voltage VOUT.

[0050] Among them, after the primary switch tube QP and the freewheeling switch tube QS are both turned off, the drain terminal voltage of the primary switch tube and the drain terminal voltage of the freewheeling switch tube both enter the free resonance stage.

[0051] It should be noted that if Figure 2As shown, when the primary switch tube is turned off and the drain terminal voltage VD_P of the primary switch tube enters the free resonance stage, the drain terminal voltage VD_S of the secondary switch tube enters the free resonance stage at the same time, and when the drain terminal voltage VD_P of the primary switch tube is at the resonance valley top position in the free resonance process, the corresponding drain terminal voltage VD_S of the freewheeling switch tube is at the resonance valley bottom position in the free resonance process; the drain terminal voltage VD_P of the primary switch tube is the resonance valley top at the starting moment of the free resonance process, and the drain terminal voltage VD_S of the freewheeling switch tube is the resonance valley bottom at the starting moment of the free resonance process.

[0052] During the actual implementation process, within a switching cycle of a switching power supply, the primary side switch tube is first turned off. At the moment the primary side switch tube is turned off, the freewheeling switch tube is turned on, and the gate drive voltage of the freewheeling switch tube enters the freewheeling conduction control stage. At the moment the freewheeling switch tube is turned off, the gate drive voltage of the freewheeling switch tube exits the freewheeling conduction control stage, and the drain terminal voltage signal of the freewheeling switch tube and the drain terminal voltage signal of the primary side switch tube enter the free resonance stage at the same time.

[0053] Among them, in the freewheeling conduction control stage, when the primary side switch tube is turned off, the freewheeling switch tube is turned on, so that the current in the excitation inductor (primary side inductor) continues to flow through the freewheeling switch tube, which is used to provide a release path for the energy stored in the excitation inductor, reduce the high voltage spikes caused by current mutation, and protect circuit components.

[0054] like Figure 2 As shown, Figure 2 The left side shows the situation where the switching power supply operates in quasi-resonant mode. During one switching cycle, the primary switch tube is turned on at the bottom position of the drain terminal voltage of the primary switch tube in the free resonance stage (the fifth valley). However, due to the high input voltage, the drain terminal voltage at the turn-on moment is still very high, and the switching loss is large. Among them, one switching cycle is the time interval from the current primary switch tube turning off to the next primary switch tube turning off.

[0055] like Figure 2 As shown, Figure 2 The right side shows the situation where the switching power supply operates in zero voltage conduction mode. Within a switching cycle, before the primary switch tube is turned on, the target switch tube can be turned on for a period of time at a certain valley top moment (the 5th valley top) of the drain terminal voltage of the primary switch tube in the free resonance stage to inject energy into the drain terminal voltage of the primary switch tube, thereby increasing the resonance amplitude of the drain terminal voltage of the primary switch tube when the free resonance is restored, thereby reducing the drain terminal voltage at the turn-on moment of the primary switch tube (the 5th valley bottom) and reducing the switching loss. When the turn-on time of the target switch tube is appropriate, the drain terminal voltage at the turn-on moment can be zero, thereby realizing zero voltage turn-on of the switching power supply.

[0056] Among them, the target switch tube will be explained below, and this application will not go into details here.

[0057] The present application can achieve adaptive adjustment of the duration of the target switch tube conduction based on the following steps.

[0058] Step 110: In the feedback regulation mode, at a target time, control the target switch tube to be turned on for a target duration and then turned off, and then obtain a target drain voltage;

[0059] In this step, the feedback regulation mode is similar to the above-mentioned zero voltage turn-on mode, except that in the feedback regulation mode, the target duration of the next turn-on of the target switch tube can be adjusted based on the target drain voltage.

[0060] It is understandable that the target duration in this step may be the duration adjusted by the last feedback regulation mode.

[0061] In some embodiments, when the target switch is turned on for the first time, the target duration may be a preset duration, which may be roughly set based on test data and is not limited here.

[0062] The switching cycle of a switching power supply is the time interval from when the primary switch tube is turned off to when it is turned off again.

[0063] The target drain voltage is the voltage at the first resonance valley bottom that appears after the drain voltage of the primary side switch tube recovers to the free resonance state after the target switch tube is turned off, or the voltage at the first resonance valley top that appears after the drain voltage of the freewheeling switch tube recovers to the free resonance state.

[0064] The target switch tube is a freewheeling switch tube or a compensation switch tube connected between the primary switch tube and the ground.

[0065] The target time is the time when the target switch tube is turned on.

[0066] The target time may include the time when the drain terminal voltage signal of the primary side switch tube reaches each resonance valley top during the free resonance process, or may include the time when the drain terminal voltage signal of the freewheeling switch tube reaches each resonance valley bottom during the free resonance process.

[0067] The target time and the target drain voltage are determined based on the target switch tube.

[0068] In some embodiments, the target time and the target drain voltage are determined based on the target switch tube, which may include:

[0069] When the target switch is a compensation switch, the target time is determined as the time when the drain voltage of the primary switch is at the target valley top during the free resonance process, and the target drain voltage is determined as the drain voltage at the first resonance valley bottom that appears after the drain voltage of the primary switch recovers to the free resonance after the compensation switch is turned off.

[0070] When the target switch tube is a freewheeling switch tube, the target time is determined as the time when the drain terminal voltage of the freewheeling switch tube is at the target bottom during the free resonance process, and the target drain terminal voltage is determined as the drain terminal voltage at the first resonance valley top that appears after the freewheeling switch tube is turned off and the drain terminal voltage of the freewheeling switch tube recovers to the free resonance.

[0071] In this embodiment, in the actual implementation process, when the target switch tube is the compensation switch tube, the target time for turning on the compensation switch tube is the time when the drain terminal voltage of the primary switch tube is at the target valley top during the free resonance process. After the compensation switch tube is turned on for the target time and then turned off, the drain terminal voltage of the primary switch tube resonates with a larger resonance amplitude toward the next resonance valley bottom (such as Figure 3 The first valley bottom of VD_P in the feedback regulation mode shown in FIG1 is the first resonance valley bottom resonance after the compensation switch is turned on. The drain voltage at the first resonance valley bottom (as shown in FIG11 ) is the first valley bottom resonance after the compensation switch is turned on. Figure 3 The VREF shown is the target drain voltage, which is used to judge the conduction effect of the target duration of the conduction compensation switch tube.

[0072] In the case where the target switch is a freewheeling switch, the target time for turning on the freewheeling switch is the time when the drain voltage of the freewheeling switch is at the target valley bottom during the free resonance process. After the freewheeling switch is turned on for the target time and turned off, the drain voltage of the freewheeling switch resonates toward the next resonance valley top with a larger resonance amplitude (such as Figure 16 The first valley of VD_S in the feedback regulation mode shown in FIG1 is the first resonance valley resonance after the compensation switch is turned on. The drain voltage at the first resonance valley is the target drain voltage (as shown in FIG1 ). Figure 16 VREF shown in the figure is used to judge the conduction effect of the target duration of the freewheeling switch tube.

[0073] It should be noted that the target valley is a preset resonance valley of the drain terminal voltage signal of the primary side switch tube when the compensation switch tube is turned on during the free resonance process.

[0074] The target valley bottom is a preset resonance valley bottom of the drain terminal voltage signal of the freewheeling switch tube when the freewheeling switch tube is turned on during the free resonance process.

[0075] In some embodiments, the number of valley tops of the target valley top and the number of valley bottoms of the target valley bottom can be customized by the user, but should not exceed the number of locked valley bottoms of the drain voltage of the primary side switching tube in the valley locking state, wherein the valley locking is used to lock the resonant valley bottom of the drain voltage of the primary side switching tube during the free resonance process to reduce the resonant valley frequency hopping phenomenon, thereby reducing audio noise and electromagnetic interference.

[0076] For example, when the locked valley bottom number is 6, the valley top number of the target valley top and the valley bottom number of the target valley bottom can be set to 1, 2, 3, 4 or 5, etc.

[0077] It can be understood that when the target switching tube is a compensation switching tube, the target time can be determined as a resonance valley top of the drain terminal voltage signal of the primary side switching tube during the free resonance process; when the target switching tube is a freewheeling switching tube, the target time can be determined as a resonance valley bottom of the drain terminal voltage signal of the freewheeling switching tube during the free resonance process.

[0078] It should be noted that the drain voltage of the freewheeling switch tube on the secondary side of the transformer is coupled from the drain voltage of the primary side switch tube on the primary side of the transformer, and the drain voltage of the freewheeling switch tube has a corresponding relationship with the drain voltage of the primary side switch tube: (1) the resonance valley bottom of the drain voltage of the freewheeling switch tube corresponds to the resonance valley top of the drain voltage of the primary side switch tube; (2) turning on the compensation switch tube or the freewheeling switch tube for the same time and duration at the same time has the same effect on injecting energy into the drain voltage of the primary side switch tube, and if after turning on the target switch tube (compensation switch tube or freewheeling switch tube), the drain voltage of the freewheeling switch tube resonates to 0V at the moment when the drain voltage of the primary side switch tube resonates to the platform voltage.

[0079] During the actual execution process, there is no communication between the primary and secondary sides of the transformer. Therefore, when the target switch tube is a compensation switch tube, whether the target time has been reached can be determined by detecting whether the drain voltage of the primary switch tube has reached the target valley top; when the target switch tube is a freewheeling switch tube, whether the target time has been reached can be determined by detecting whether the drain voltage of the freewheeling switch tube has reached the target valley bottom, thereby more intuitively and accurately determining whether the time to turn on the target switch tube has been reached for different target switch tubes.

[0080] According to the control method of the switching power supply provided in the embodiment of the present application, the target time and the target drain voltage are determined based on the target switching tube, so that the determined target time and target drain voltage can be matched with the target switching tube. Therefore, in actual application, the control of the target switching tube and the judgment of the effect of subsequently turning on the target switching tube can be performed more intuitively and accurately based on the determined target time and target drain voltage.

[0081] Step 120 : Based on the target drain voltage and the target voltage range, determine the target duration corresponding to the next turn-on of the target switch tube until the target drain voltage is within the target voltage range.

[0082] In this step, the target switch tube may be turned on for the next switching cycle.

[0083] The target voltage range is a preset ideal voltage range for zero voltage turn-on.

[0084] During the actual execution process, the current zero-voltage turn-on effect can be determined by judging whether the target drain voltage is within the target voltage range, and then the target duration corresponding to the next turn-on of the target switch tube can be adjusted based on the effect, so that the effect of the next turn-on of the target switch tube can be better based on the adjusted target duration, and this cycle is repeated until the target drain voltage is within the target voltage range.

[0085] Among them, in each switching cycle, when the target drain voltage is within the target voltage range, the target duration of the next turn-on of the target switch tube can be controlled to remain unchanged; when the target drain voltage is outside the target voltage range, the target duration can be adjusted accordingly based on the difference between the target drain voltage and the target voltage range, thereby reducing the difference between the target drain voltage and the target voltage range.

[0086] It should be noted that the longer the target time is, the greater the resonance amplitude of the drain voltage of the primary switching tube or the drain voltage of the freewheeling switching tube after the free resonance is restored. It can be understood that the longer the target time is, the smaller the target drain voltage corresponding to the primary switching tube is, and the larger the target drain voltage corresponding to the freewheeling switching tube is.

[0087] In actual execution, when the current switching cycle is the starting cycle, the target duration corresponding to the current switching cycle is the preset duration, wherein the starting cycle is the first switching cycle when the switching power supply just starts working.

[0088] In some embodiments, the preset time length can be customized by the user based on experience values, as long as it can meet the subsequent execution logic of the switching power supply during actual execution, and is not limited here.

[0089] In some embodiments, any feasible adjustment method can be adopted to adjust the target duration based on the effect of turning on the target switch tube. For example, the correspondence between the difference between the ideal effect of turning on the target switch tube and the actual effect of turning on the target switch tube and the target duration adjustment amount can be pre-set, that is, the correspondence between the difference between the target drain voltage and the target voltage range and the target duration adjustment amount. During the actual execution process, the adjustment amount is determined based on the correspondence between the actual effect difference and the adjustment amount to adjust the target duration, thereby improving the reliability of the target duration, so that the adjusted target duration can be used for the next cycle, thereby reducing the difference between the actual effect of turning on the target switch tube and the ideal effect of turning on the target switch tube in the next cycle.

[0090] The target voltage range is determined based on the target switch tube.

[0091] It can be understood that when the compensation switch tube is turned on, the ideal zero voltage turn-on effect is: after the compensation switch tube is turned on for the target time, the target drain voltage corresponding to the primary switch tube is zero voltage.

[0092] When the freewheeling switch is turned on: the ideal zero-voltage turn-on effect is: after the freewheeling switch is turned on for the target time, the target drain voltage corresponding to the freewheeling switch is the platform voltage corresponding to the drain voltage of the freewheeling switch, that is, the peak voltage of the drain voltage of the freewheeling switch.

[0093] During the actual execution process, when the target switch tube is a compensation switch tube, the target voltage range can be a voltage within a first preset range close to 0; when the target switch tube can be a freewheeling switch tube, the target voltage range is a voltage within a second preset range close to the platform voltage of the freewheeling switch tube (the platform voltage of the drain terminal voltage of the freewheeling switch tube).

[0094] Among them, the first preset range and the second preset range can be customized based on actual circuit requirements. For example, the first preset range can be set to 0.1~1V or 0.2~2V, etc. Assuming that the platform voltage of the freewheeling switch tube is 20V, the second preset range can be set to 19V~19.9V or 18V~19.8V, etc. Of course, in other embodiments, the first preset range and the second preset range can also be set to other ranges that meet the requirements, which are not limited here.

[0095] During the research and development process, the inventors discovered that in actual circuits, the duration of the target switch on-time is affected by numerous factors, including input voltage, output voltage, system conduction valleys, system design parameters, and PCB parasitic parameters. This means that the optimal compensation on-time varies with these numerous parameters, making it difficult to obtain the optimal compensation on-time. This, in turn, leads to poor zero-voltage turn-on performance.

[0096] According to the control method of the switching power supply provided in the embodiment of the present application, by controlling the target switch tube to be turned on for a target duration and then turned off at a target time in a feedback regulation mode, obtaining the target drain voltage corresponding to the primary switch tube or the freewheeling switch tube, and determining the target duration corresponding to the next turn-on of the target switch tube based on the target drain voltage and the target voltage range, until the target drain voltage is within the target voltage range, the zero voltage turn-on effect represented by the comparison result of the target drain voltage and the target voltage range can be achieved, and the target duration is adjusted so that the adjusted target duration is used for the next zero voltage turn-on, thereby reducing the gap between the next target drain voltage and the target voltage range and improving the zero voltage turn-on effect. In this cycle, the target duration is adaptively adjusted during the operation of the switching power supply, thereby adaptively adjusting the actual effect of the zero voltage turn-on control, improving the accuracy and reliability of the zero voltage turn-on control, thereby further reducing the loss of the switching power supply and improving the system efficiency.

[0097] In some embodiments, when the target switch is a compensation switch, the target voltage range is a voltage within a first preset range close to 0; when the target switch is a freewheeling switch, the target voltage range is a voltage within a second preset range close to the platform voltage of the freewheeling switch, which may include:

[0098] When the target switch is a compensation switch, the first voltage is determined as a first threshold voltage in the target voltage range, and the second voltage is determined as a second threshold voltage in the target voltage range.

[0099] When the target switch tube is a freewheeling switch tube, the third voltage is determined as a first threshold voltage in the target voltage range, and the fourth voltage is determined as a second threshold voltage in the target voltage range;

[0100] or,

[0101] When the target switch is a compensation switch, the fifth voltage is determined to be a third threshold voltage in the target voltage range.

[0102] When the target switch tube is a freewheeling switch tube, the sixth voltage is determined as a third threshold voltage in the target voltage range.

[0103] In this embodiment, the first voltage is greater than the second voltage.

[0104] The second voltage is a voltage whose difference from the zero voltage is less than a first preset threshold, or is an equivalent conversion voltage (for example, voltage division or attenuation conversion) of the drain voltage of the primary switch tube.

[0105] The first preset threshold value may be customized based on actual circuit requirements. For example, the first preset threshold value may be set to 0.01, 0.1, or 0.2, etc., which is not limited here.

[0106] It is understandable that the second voltage may be the lower boundary of the first preset range close to 0, the first voltage may be the upper boundary of the first preset range, or any voltage between the second voltage and the upper boundary.

[0107] For example, when the second voltage is 0.1V and the first preset range is 0.1V to 1V, the first voltage can be any voltage greater than 0.1V within the range of 0.1V to 1V.

[0108] The fourth voltage is greater than the third voltage.

[0109] The fourth voltage is a voltage whose difference from the platform voltage of the freewheeling switch tube is less than a second preset threshold, or is an equivalent conversion voltage of the platform voltage of the drain terminal voltage of the freewheeling switch tube.

[0110] The second preset threshold is set in the same manner as the first preset threshold, and will not be described in detail here.

[0111] It is understandable that the fourth voltage may be the upper limit of the second preset range close to the platform voltage of the freewheeling switch tube, the third voltage may be the lower limit of the second preset range, or any voltage between the fourth voltage and the lower limit.

[0112] The fifth voltage is a voltage whose difference from the zero voltage is smaller than a third preset threshold.

[0113] The sixth voltage is a voltage whose difference from the platform voltage of the freewheeling switch tube is less than a fourth preset threshold.

[0114] The third preset threshold and the fourth preset threshold are set in the same manner as the first preset threshold and the second preset threshold, and are not described in detail here.

[0115] The third preset threshold value may be the same as or different from the first preset threshold value, and similarly, the fourth preset threshold value may be the same as or different from the second preset threshold value. It is understood that the target voltage range may include the first threshold voltage and the second threshold voltage.

[0116] Among them, when the target switching tube is a compensation switching tube, the second threshold voltage can be a voltage close to zero voltage, or it can also be an equivalent transformation voltage obtained by voltage division or attenuation transformation of the drain voltage of the primary switching tube. The first threshold voltage can be any voltage greater than the second threshold voltage within the first preset range. The specific voltage can be determined based on actual conditions and is not limited here.

[0117] When the target switch tube is a freewheeling switch tube, the second threshold voltage can be a voltage close to the platform voltage of the drain terminal voltage of the freewheeling switch tube, or it can also be an equivalent transformation voltage obtained by voltage division or attenuation transformation of the platform voltage. The first threshold voltage can be any voltage greater than the second threshold voltage within the second preset range. The specific voltage can be determined based on actual conditions and is not limited here.

[0118] In actual implementation, the zero voltage turn-on effect can be obtained based on a comparison between the target drain voltage and a target voltage range including a first threshold voltage and a second threshold voltage.

[0119] It can be understood that the target voltage range may further include a third threshold voltage.

[0120] In the case where the target switch tube is a compensation switch tube, the third threshold voltage may be a voltage close to zero voltage.

[0121] In the case where the target switch tube is a freewheeling switch tube, the third threshold voltage may be a voltage close to a platform voltage of the drain terminal voltage of the freewheeling switch tube.

[0122] In actual implementation, the zero voltage turn-on effect can be obtained based on a comparison between the target drain voltage and a target voltage range including the third threshold voltage.

[0123] According to the control method of the switching power supply provided in the embodiment of the present application, by respectively determining the first voltage or the third voltage as the first threshold voltage in the target voltage range when the target switching tube is a compensation switching tube or a freewheeling switching tube, and respectively determining the second voltage or the fourth voltage as the second threshold voltage in the target voltage range, or, when the target switching tube is a compensation switching tube or a freewheeling switching tube, respectively determining the fifth voltage or the sixth voltage as the third threshold voltage in the target voltage range, a variety of representations and determination methods of the target voltage range can be achieved, thereby improving the flexibility of the method for determining the target voltage range and the adaptability of the determined target voltage range.

[0124] In some embodiments, the target voltage range includes a first threshold voltage and a second threshold voltage, where the second threshold voltage is less than the first threshold voltage. Determining a target duration corresponding to the next turn-on of the target switch based on the target drain voltage and the target voltage range may include:

[0125] When the target drain voltage is less than the first threshold voltage and greater than the second threshold voltage, the target duration corresponding to the next turn-on of the target switch tube remains unchanged;

[0126] When the target drain voltage is not less than the first threshold voltage and greater than the second threshold voltage, the target duration corresponding to the next turn-on of the target switch tube is adjusted based on the target switch tube and based on the relationship between the target drain voltage and the first threshold voltage and the second threshold voltage.

[0127] In this embodiment, it can be understood that when the target drain voltage is within the target voltage range including the first threshold voltage and the second threshold voltage, that is, the zero-voltage turn-on achieves the ideal effect, then the target duration corresponding to the next turn-on of the target switch tube can be controlled to remain unchanged, that is, the target duration of the next turn-on of the target switch tube is consistent with the target duration of the current turn-on of the target switch tube.

[0128] When the target drain voltage is outside the target voltage range including the first threshold voltage and the second threshold voltage, the target duration corresponding to the next turn-on of the target switch tube can be adjusted based on the size relationship between the target drain voltage and the first threshold voltage and the second threshold voltage, when the target switch tube is a compensation switch tube or a freewheeling switch tube.

[0129] In some embodiments, the correspondence between the difference between the target drain voltage and the first threshold voltage and the second threshold voltage and the target duration adjustment amount can be pre-set. During the actual implementation process, based on the actual effect difference, that is, the actual difference between the target drain voltage and the first threshold voltage and the second threshold voltage, the adjustment amount of the target duration is determined based on the correspondence, so as to adjust the target duration based on the adjustment amount, thereby improving the reliability of the target duration.

[0130] In some embodiments, the target duration may also be adjusted based on a fixed step length, which will be specifically described in the following embodiments and will not be elaborated here.

[0131] According to the control method of the switching power supply provided in the embodiment of the present application, when the target voltage range includes the first threshold voltage and the second threshold voltage, and when the target drain voltage is less than the first threshold voltage and greater than the second threshold voltage, the target duration corresponding to the next turn-on of the target switch tube remains unchanged; when the target drain voltage is not less than the first threshold voltage and greater than the second threshold voltage, the target duration corresponding to the next turn-on of the target switch tube is adjusted based on the target switch tube and based on the size relationship between the target drain voltage and the first threshold voltage and the second threshold voltage. This can achieve a more accurate zero-voltage turn-on effect based on the comparison result of the first threshold voltage and the second threshold voltage with the target drain voltage, thereby improving the accuracy of the adjustment control of the target duration and improving the reliability of the control method.

[0132] In some embodiments, adjusting the target duration corresponding to the next turn-on of the target switch tube based on the target switch tube and based on the relationship between the target drain voltage and the first threshold voltage and the second threshold voltage may include:

[0133] When the target switch is a compensation switch and the target drain voltage is greater than or equal to the first threshold voltage, increasing the target time based on the target step size;

[0134] When the target switch is a compensation switch and the target drain voltage is less than or equal to the second threshold voltage, reducing the target time based on the target step size;

[0135] When the target switch tube is a freewheeling switch tube and the target drain terminal voltage is greater than or equal to the first threshold voltage, reducing the target time length based on the target step length;

[0136] When the target switch tube is a freewheeling switch tube and the target drain terminal voltage is less than or equal to the second threshold voltage, the target time length is increased based on the target step length.

[0137] In this embodiment, the target step length is a certain duration.

[0138] During the actual execution process, the target duration can be customized by the user.

[0139] For example, the target duration may be determined as 50 nS, 60 nS, or 100 nS.

[0140] Of course, in other embodiments, the target duration can also be determined as other durations, as long as it meets the subsequent execution logic of the switching power supply, and this application does not limit this.

[0141] like Figure 3 As shown, in the actual implementation process, when the target switch tube is the compensation switch tube, the longer the target time length TZVS_ON is, the smaller the drain voltage of the primary side switch tube at the second valley bottom is.

[0142] like Figure 3As shown, it can be understood that, when the target switch tube is a compensation switch tube, when it is detected that the target drain voltage (VREF) is greater than or equal to the first threshold voltage (VTH_H), it indicates that the target duration is too short, the compensation injection energy is too small, and the zero voltage turn-on effect is poor. In this case, the target duration can be increased based on the target step size, so that the target drain voltage (VREF) is less than the first threshold voltage (VTH_H); when it is detected that the target drain voltage (VREF) is less than or equal to the second threshold voltage (VTH_L), it indicates that the target duration is too long, the compensation injection energy is redundant, and unnecessary power circulation will be formed, resulting in additional loss. In this case, the target duration can be reduced based on the target step size, so that the target drain voltage (VREF) is greater than the second threshold voltage (VTH_L); when it is detected that the target drain voltage (VREF) is less than the first threshold voltage (VTH_H) and greater than the second threshold voltage (VTH_L), it indicates that the current compensation injection energy is appropriate and the zero voltage turn-on effect is good, so the target duration can be controlled unchanged.

[0143] like Figure 16 As shown, in the actual execution process, when the target switch tube is a freewheeling switch tube, the longer the target time length TZVS_ON is, the greater the drain terminal voltage of the freewheeling switch tube at the second valley top is.

[0144] like Figure 16 As shown, it can be understood that, when the target switch tube is a freewheeling switch tube, when it is detected that the target drain terminal voltage (VREF) is greater than or equal to the first threshold voltage (VTH_H), it indicates that the target duration is too large, the compensation injection energy is redundant, and unnecessary power circulation will be formed, resulting in additional loss. In this case, the target duration can be reduced based on the target step size, so that the target drain terminal voltage (VREF) is less than the first threshold voltage (VTH_H); when it is detected that the target drain terminal voltage (VREF) is less than or equal to the second threshold voltage (VTH_L), it indicates that the target duration is too short, the compensation injection energy is too small, and the zero voltage turn-on effect is poor. In this case, the target duration can be increased based on the target step size, so that the target drain terminal voltage (VREF) is greater than the second threshold voltage (VTH_L); when it is detected that the target drain terminal voltage (VREF) is less than the first threshold voltage (VTH_H) and greater than the second threshold voltage (VTH_L), it indicates that the current compensation injection energy is appropriate and the zero voltage turn-on effect is good, so the target duration can be controlled unchanged.

[0145] It can be understood that in some embodiments, when the target switch tube is a compensation switch tube, the final zero voltage conduction effect can be affected by adjusting the relative distance between the first threshold voltage and the second threshold voltage compared to the zero voltage, and when the target switch tube is a freewheeling switch tube, the final zero voltage conduction effect can be affected by adjusting the relative distance between the first threshold voltage and the second threshold voltage compared to the platform voltage of the drain voltage of the freewheeling switch tube.

[0146] In some embodiments, a fourth threshold voltage can also be set. When the target switch tube is a compensation switch tube, the fourth threshold voltage can be set to be much larger than the second threshold voltage; when the target switch tube is a freewheeling switch tube, the fourth threshold voltage can be set to be much smaller than the first threshold voltage.

[0147] During the actual implementation process, when the target switch tube is a compensation switch tube and the target drain terminal voltage is greater than or equal to the fourth threshold voltage, or when the target switch tube is a freewheeling switch tube and the target drain terminal voltage is less than or equal to the fourth threshold voltage, it indicates that the compensation injection energy is seriously insufficient. The target step size can be adjusted based on the acceleration factor, and the target time can be increased based on the adjusted target step size, which can shorten the time from the start of adjustment of the switching power supply system to the system achieving a relatively ideal zero voltage turn-on effect.

[0148] In some embodiments, the target step length increased by the target duration based on the acceleration factor adjustment can be expressed as follows:

[0149] T ZVS_ON =t+k*t0

[0150] Among them, T ZVS_ON is the target duration after adjustment, t is the target duration before adjustment, k is the acceleration factor, t0 is the target step size, and k is greater than 1.

[0151] When the target switch tube is a compensation switch tube and the target drain terminal voltage is less than the fourth threshold voltage and greater than the first threshold voltage, or when the target switch tube is a freewheeling switch tube and the target drain terminal voltage is greater than the fourth threshold voltage and less than the second threshold voltage, it indicates that the compensation injection energy is approaching the expected value. The target duration can be adjusted based on the target step length that has not been adjusted by the acceleration factor, thereby reducing the risk of directly placing the compensation injection energy in a redundant state due to excessive jumps in the target duration.

[0152] According to the control method of the switching power supply provided in the embodiment of the present application, by respectively increasing or decreasing the target duration corresponding to the current switching cycle based on the target step size based on the size relationship between the target drain voltage and the first threshold voltage and the second threshold voltage when the target switching tube is a compensation switching tube or a freewheeling switching tube, the effect of actually turning on the target switching tube based on multiple cycles can be achieved, the target duration can be gradually adjusted, the stability of the target duration adjustment can be improved, and thus the stability of the switching power supply can be improved.

[0153] In some embodiments, the target voltage range includes a third threshold voltage; and determining a target duration corresponding to the next turn-on of the target switch based on the target drain voltage and the target voltage range may include:

[0154] The difference between the target drain terminal voltage and the third threshold voltage is subjected to PI control to adjust the target duration corresponding to the next turn-on of the target switch tube.

[0155] In this embodiment, when the target switch tube is a compensation switch tube, the third threshold voltage can be a voltage close to zero voltage; when the target switch tube is a freewheeling switch tube, the third threshold voltage can be a voltage close to the platform value of the drain voltage of the freewheeling switch tube.

[0156] PI control is proportional-integral control, a feedback control algorithm.

[0157] In the actual implementation process, based on PI control, the goal can be to eliminate the difference between the target drain voltage and the third threshold voltage, that is, to control the difference between the target drain voltage and the third threshold voltage to 0, and adjust the target duration, so that the adjusted target duration can be used for the next zero-voltage conduction, thereby improving the next zero-voltage conduction effect.

[0158] According to the control method of the switching power supply provided in the embodiment of the present application, by performing PI control on the difference between the target drain voltage and the third threshold voltage when the target voltage range includes the third threshold voltage, and adjusting the target duration corresponding to the next turn-on of the target switch tube, it is possible to adjust the target duration with the goal of eliminating the difference between the target drain voltage and the third threshold voltage, and provide other adjustment methods in addition to adjusting the target duration based on the magnitude relationship between the target drain voltage and the first threshold voltage and the second threshold voltage, thereby improving the flexibility and adaptability of the method for adjusting the target duration.

[0159] In some embodiments, the target voltage range includes a third threshold voltage, and the third threshold voltage can be determined based on the following steps:

[0160] With the final zero-voltage turn-on effect as the goal, when the target switch tube is a compensation switch tube, the third threshold voltage is determined by adjusting the relative distance of the third threshold voltage compared to the zero voltage; when the target switch tube is a freewheeling switch tube, the third threshold voltage is determined by adjusting the relative distance of the third threshold voltage compared to the platform voltage of the freewheeling switch tube.

[0161] In this embodiment, the final zero-voltage turn-on effect can be a custom-set optimal zero-voltage turn-on effect. For example, the optimal zero-voltage turn-on effect can be a turn-on effect in which the target drain voltage is zero voltage when the target switch tube is a compensation switch tube, or a turn-on effect in which the target drain voltage is the platform voltage of the freewheeling switch tube when the target switch tube is a freewheeling switch tube. This is not limited here.

[0162] Based on the PI control in the above embodiment, it can be known that since the difference between the target drain voltage and the third threshold voltage is controlled by PI, the target duration corresponding to the next turn-on of the target switch tube can be adjusted, and the adjusted target duration can be used for the next zero-voltage turn-on to improve the next zero-voltage turn-on effect. It can be understood that when the target switch tube is a compensation switch tube, the final zero-voltage turn-on effect can be affected by adjusting the relative distance of the third threshold voltage compared to the zero voltage, and when the target switch tube is a freewheeling switch tube, the final zero-voltage turn-on effect can be affected by adjusting the relative distance of the third threshold voltage compared to the platform voltage of the drain voltage of the freewheeling switch tube.

[0163] During the actual execution process, the third threshold voltage can be adjusted based on the final zero-voltage turn-on effect, and a new zero-voltage turn-on effect can be obtained based on the adjusted third threshold voltage, and the cycle is repeated until the actual zero-voltage turn-on effect matches the final zero-voltage turn-on effect.

[0164] According to the control method of the switching power supply provided in the embodiment of the present application, by taking the final zero-voltage turn-on effect as the target, when the target switch tube is a compensation switch tube, by adjusting the relative distance of the third threshold voltage compared to the zero voltage, and when the target switch tube is a freewheeling switch tube, by adjusting the relative distance of the third threshold voltage compared to the platform voltage of the freewheeling switch tube, the third threshold voltage is determined. This can achieve a customized optimal zero-voltage turn-on effect, and feedback adjustment of the third threshold voltage to improve the reliability and applicability of the third threshold voltage, thereby further improving the zero-voltage turn-on effect based on the adjusted third threshold voltage.

[0165] In some embodiments, after determining a target duration corresponding to the next turn-on of the target switch based on the target drain voltage and the target threshold voltage, the method may further include:

[0166] If the target duration is less than or equal to the minimum duration, update the target duration to the minimum duration;

[0167] When the target duration is greater than the minimum duration and less than the maximum duration, the target duration is controlled to remain unchanged;

[0168] If the target duration is greater than or equal to the maximum duration, the target duration is updated to the maximum duration.

[0169] In this embodiment, the minimum duration is a preset minimum limit duration for turning on the target switch tube.

[0170] The maximum duration is a preset maximum limit duration for turning on the target switch tube.

[0171] During the actual implementation process, in order to reduce the risk of premature shutdown of the target switch tube due to circuit interference, which results in too short a conduction time of the target switch tube and poor zero-voltage conduction effect, the minimum limit time for turning on the target switch tube can be pre-set to ensure a certain conduction effect; the primary side controller of the switching power supply is set with a maximum cycle limit and a maximum waiting time for valley detection, that is, when the switching cycle time reaches the maximum cycle limit or the maximum waiting time for valley detection, the primary side controller will force the primary side switch tube to turn on. In order to reduce circuit risks, the maximum limit time for turning on the target switch tube can be pre-set.

[0172] In the actual implementation process, the minimum duration and the maximum duration are both set to values that comply with the subsequent control logic of the switching power supply, and this application does not limit this.

[0173] It can be understood that after adjusting the target duration corresponding to the current switching cycle based on the size relationship between the target drain voltage and the first threshold voltage and the second threshold voltage, the target duration can also be limited. When the target duration exceeds the limiting range formed by the minimum duration and the maximum duration, the target duration is determined as the boundary value of the limiting range, that is, if the target duration is less than or equal to the minimum duration, the target duration is determined as the minimum duration; if the target duration is greater than or equal to the maximum duration, the target duration is determined as the maximum duration; if the target duration is within the limiting range, it remains unchanged.

[0174] According to the control method of the switching power supply provided in the embodiment of the present application, by limiting the target duration, the safety and stability of the switching power supply can be improved when the target switch tube is subsequently turned on based on the processed target duration.

[0175] In some embodiments, the switching power supply includes a transformer, a primary switching tube connected to the primary side of the transformer, and a freewheeling switching tube connected to the secondary side of the transformer; the control method of the switching power supply may further include:

[0176] During the current switching cycle of the switching power supply, the target switch is controlled to be turned on at the target time to inject energy into the resonant unit of the primary switch;

[0177] After the target duration, turn off the target switch tube;

[0178] When the drain voltage of the primary switch tube reaches the target resonance valley, the primary switch tube is controlled to be turned on, and the target duration is determined as the target duration corresponding to the next turn-on of the target switch tube.

[0179] In this embodiment, the target resonance valley is the resonance valley at which the drain voltage of the corresponding primary switch tube is located at the moment when the target drain voltage is located.

[0180] In actual implementation, this embodiment is a compensation conduction mode. In the compensation conduction mode, the target duration corresponding to the next turn-on of the target switch tube is consistent with the target duration corresponding to the current turn-on of the target switch tube.

[0181] It can be understood that the compensation conduction mode is the zero voltage conduction mode described above.

[0182] The control method described in the above steps 110 to 120 is a feedback regulation mode. In the actual implementation process, the difference between the feedback regulation mode and the compensation conduction mode is that in the feedback regulation mode, the target duration of the next turn-on of the target switch tube is adjusted based on the target drain voltage, while the compensation conduction mode does not adjust the target duration.

[0183] In some embodiments, each switching cycle can be a feedback regulation mode or a compensation conduction mode, but since the compensation conduction mode does not adjust the target duration, if the purpose of adaptive adjustment of the zero voltage conduction effect is to be achieved, the intervention cycle interval or time interval of the feedback regulation mode can be set.

[0184] According to the control method of the switching power supply provided in the embodiment of the present application, by controlling the target switching tube to be turned on at the target time within the current switching cycle of the switching power supply to inject energy into the resonant unit of the primary switching tube, turning off the target switching tube after the target duration, and controlling the primary switching tube to be turned on when the drain voltage of the primary switching tube reaches the target resonance valley, and determining the target duration as the target duration corresponding to the next turn-on of the target switching tube, zero voltage turn-on can be achieved without adjusting the target duration, thereby improving the zero voltage turn-on efficiency.

[0185] In some embodiments, the method may further include:

[0186] After determining the target duration for the next turn-on of the target switch based on the target drain voltage and the target voltage range, the feedback regulation mode is exited and the interval timing for the next feedback regulation mode intervention is performed, so that the target drain voltage is within the target voltage range after multiple feedback intervention adjustments;

[0187] After determining the target duration corresponding to the next turn-on of the target switch tube based on the target drain voltage and the target voltage range, return to execute the control of the target switch tube to be turned on for the target duration and turned off at the target time, obtain the target drain voltage until the target drain voltage is within the target voltage range, exit the feedback regulation mode and start the interval timing for the next feedback regulation mode intervention.

[0188] In this embodiment, during the operation of the switching power supply, an intermittent manner can be used to enter a single feedback regulation mode, that is, a period of time is separated between two feedback regulation modes. For example, the switching power supply enters a feedback regulation mode once every n compensation conduction modes, that is, the length of time the target switch tube is turned on is adjusted once, where n is equal to 0 or a positive integer greater than 0.

[0189] In some embodiments, during the operation of the switching power supply, the switching power supply can enter the feedback regulation mode m times in an intermittent manner, that is, the switching power supply enters the feedback regulation mode at regular intervals, and exits the feedback regulation mode after operating in the feedback regulation mode m times, where m is a positive integer greater than 1, and the value of m can be determined based on how many times the feedback regulation mode can adjust the length of the conduction time of the target switch tube to the conduction time expected by the user.

[0190] It can be understood that the intervention method of the above-mentioned first feedback regulation mode is: after entering the feedback regulation mode once, directly exit the feedback regulation mode, and start the interval timing of the next feedback regulation mode intervention, so that the time of turning on the target switch tube is adjusted to an appropriate value after multiple feedback intervention adjustments; the intervention method of the above-mentioned second feedback regulation mode is: after entering the feedback regulation mode once, continue to maintain the feedback regulation mode until the time of turning on the target switch tube is adjusted to an appropriate value, then exit the feedback regulation mode and start the interval timing of the next feedback regulation mode intervention.

[0191] Among them, compared with the access method of the second feedback regulation mode, the intervention method of the first feedback regulation mode can adjust the turn-on time of the target switch tube more stably and flexibly, so the inventor prefers to adopt the intervention method of the first feedback regulation mode.

[0192] The following describes a method for determining the operating mode within the current switching cycle under the intervention method of the first feedback regulation mode.

[0193] In some embodiments, a target time interval for the switching power supply to enter the feedback regulation mode can be pre-set, and when the switching power supply starts working, the timer starts from 0. Whenever the timer reaches the target time interval, the switching power supply is controlled to enter the feedback regulation mode. When the switching cycle at the current moment ends, the switching power supply exits the feedback regulation mode, resets the timer, and restarts the timer, and the cycle continues.

[0194] The target time interval is any multiple of the switching period, which is not limited in this application.

[0195] In some embodiments, the operating mode (compensated conduction mode and feedback regulation mode) of the switching power supply in the current switching cycle can also be determined based on the high and low levels of the square wave signal generated by the gate drive voltage signal of the primary or secondary side of the switching power supply. The details will be explained in the embodiments below and will not be repeated here.

[0196] It should be noted that, in the actual implementation process, the target time corresponding to different working modes is different, which will be specifically explained in the following embodiments and will not be elaborated here.

[0197] According to the control method of the switching power supply provided in the embodiment of the present application, the feedback regulation mode is intervened based on a certain intervention method, so that the feedback regulation mode and the compensation conduction mode exist alternately in each switching cycle of the switching power supply, thereby achieving adaptive adjustment of the zero voltage conduction effect while ensuring a certain zero voltage conduction efficiency, thereby improving the reliability of the control method.

[0198] The target moments in the compensation conduction mode and the feedback regulation mode are described below.

[0199] In some embodiments, when the target switch is a compensation switch and the operating mode is a compensation conduction mode, the first resonance valley peak of the drain terminal voltage of the primary switch during the free resonance process may be determined as the target valley peak.

[0200] When the working mode is the feedback regulation mode, the first resonance valley top or the second resonance valley top of the drain terminal voltage of the primary side switch tube in the free resonance process can be determined as the target valley top, and the time when the target valley top is located is the target time.

[0201] In this embodiment, the first resonance valley may be any resonance valley of the drain terminal voltage of the primary side switch tube during the free resonance process.

[0202] The second resonance valley is a resonance valley in a resonance cycle preceding the first resonance valley.

[0203] The resonance period is the time interval between two adjacent resonance valley tops or two adjacent resonance valley bottoms of the drain terminal voltage of the primary side switch tube or the freewheeling switch tube in the switching power supply during the free resonance process.

[0204] The resonance period of the drain terminal voltage of the primary side switch tube is the time interval between the current resonance valley top and the next resonance valley top.

[0205] For example, when the number of valley tops of the first resonance valley tops is 2, the number of valley tops of the second resonance valley tops is 1; when the number of valley tops of the first resonance valley tops is 3, the number of valley tops of the second resonance valley tops is 2.

[0206] It can be understood that the target valley in the feedback regulation mode may be the same as that in the compensation conduction mode, or the target valley in the feedback regulation mode may be one resonance cycle earlier than that in the compensation conduction mode.

[0207] In the actual implementation process, the second resonance valley top and the first resonance valley top of the drain terminal voltage of the primary side switch tube in the free resonance process are two adjacent resonance valley tops, and the resonance valley top characteristics are similar. The effect of adjusting the turn-on time of the compensation switch tube in the feedback regulation mode, that is, the drain terminal voltage at the moment of the primary side switch tube being turned on is close, then in the feedback regulation mode, the second resonance valley top can also be determined as the target valley top, thereby improving the flexibility of the feedback regulation mode.

[0208] It should be noted that when the target switch tube is the compensation switch tube and the working mode within the switching cycle is the feedback regulation mode, the subsequent turn-on moment of the primary switch tube is consistent with the turn-on moment of the primary switch tube in the compensation conduction mode, that is, in the feedback regulation mode, if the compensation switch tube is turned on at the second resonance valley top to inject energy into the drain voltage of the primary switch tube, and after the compensation switch tube is turned off, the drain voltage of the primary switch tube returns to the free resonance state and continues to resonate, and continues to maintain resonance when it resonates to the first resonance valley top until the primary switch tube is turned on.

[0209] According to the control method of the switching power supply provided in the embodiment of the present application, when the working mode is the compensation conduction mode, the first resonance valley top of the drain terminal voltage of the primary side switching tube in the free resonance process is determined as the target valley top; when the working mode is the feedback regulation mode, the first resonance valley top or the second resonance valley top of the drain terminal voltage of the primary side switching tube in the free resonance process is determined as the target valley top. It can be provided that when the target switching tube is the compensation switching tube, a method for determining multiple target moments in the compensation conduction mode can be provided, thereby improving the control flexibility and applicability of the compensation conduction mode.

[0210] In some embodiments, when the target switch is a freewheeling switch and the operating mode is a compensation conduction mode, the third resonance valley of the drain terminal voltage signal of the freewheeling switch during the free resonance process is determined as the target valley.

[0211] When the working mode is the feedback regulation mode, the fourth resonance valley of the drain terminal voltage signal of the freewheeling switch tube in the free resonance process is determined as the target valley; the time at which the target valley is located is the target time.

[0212] In this embodiment, the third resonance valley may be any resonance valley of the drain terminal voltage signal of the freewheeling switch tube during the free resonance process.

[0213] The fourth resonance valley is a resonance valley in a resonance cycle preceding the third resonance valley.

[0214] In the actual implementation process, when the valley number of the third resonance valley is 1, the valley number of the fourth resonance valley is 0. In this case, during the switching cycle of the feedback regulation mode, the subsequent freewheeling switch tube is not turned on, thereby reducing circuit risks.

[0215] It can be understood that, when the target switch tube is a freewheeling switch tube, the target valley bottom in the feedback regulation mode is one resonance cycle earlier than the target valley bottom in the compensation conduction mode.

[0216] It should be noted that when the target switch tube is a freewheeling switch tube and the operating mode within the switching cycle is the feedback regulation mode, the subsequent turn-on moment of the primary switch tube is consistent with the turn-on moment of the primary switch tube in the compensation conduction mode, which is similar to the above-mentioned compensation switch tube case and will not be elaborated here.

[0217] In actual implementation, the secondary side of the transformer cannot obtain the resonance period and the turn-on moment of the primary side switch tube after turning on the freewheeling switch tube to inject energy into the drain voltage of the primary side switch tube, but can detect the peak voltage of the drain voltage of the freewheeling switch tube.

[0218] Therefore, if Figure 16 As shown, in the case where the target switch tube is a freewheeling switch tube, if the target valley bottom in the feedback regulation mode is determined to be the third resonant valley bottom (the second valley bottom of VD_S), that is, the same as the target valley bottom in the compensation conduction mode, since the subsequent freewheeling switch tube is turned on at the third resonant valley bottom, it is impossible to obtain how long it takes to delay in order to collect the drain voltage VD_S of the freewheeling switch tube at the turn-on moment of the subsequent primary side switch tube (the second valley top), that is, it is impossible to obtain the effect of turning on the freewheeling switch tube to inject energy into the drain voltage VD_P of the primary side switch tube, and it is also impossible to make subsequent effective adjustments to the target duration based on this effect.

[0219] At the fourth resonance valley bottom (first valley bottom), the freewheeling switch tube is turned on to inject energy into the drain voltage VD_P of the primary switch tube. After the freewheeling switch tube is turned off, the drain voltage VD_S of the freewheeling switch tube returns to the free resonance state and continues to resonate until the primary switch tube is turned on (second valley top). The resonant voltage VREF of the resonance valley top (first valley top) between the peak voltage fourth resonance valley bottom (first valley bottom) and the third resonance valley bottom (second valley bottom) can be detected to obtain the effect of turning on the freewheeling switch tube to inject energy into the drain voltage VD_P of the primary switch tube, thereby realizing effective adjustment of the target duration based on this effect.

[0220] According to the control method of the switching power supply provided in the embodiment of the present application, when the working mode is the compensation conduction mode, the third resonance valley of the drain-terminal voltage signal of the freewheeling switch tube in the free resonance process is determined as the target valley, and when the working mode is the feedback regulation mode, the fourth resonance valley of the drain-terminal voltage signal of the freewheeling switch tube in the free resonance process is determined as the target valley. This can improve the rationality of determining the target valley corresponding to the working mode when the target switch tube is the freewheeling switch tube, thereby realizing the effective implementation of the compensation conduction mode and the feedback regulation mode when the target switch tube is the freewheeling switch tube.

[0221] In some embodiments, within the same switching cycle, the feedback regulation mode and the compensation conduction mode can coexist, except that the target moment in the feedback regulation mode is one resonant cycle ahead of the target moment in the compensation conduction mode, and when the compensation conduction mode and the feedback regulation mode coexist, the target duration corresponding to the compensation conduction mode in each switching cycle is obtained by adjusting the target duration corresponding to the compensation conduction mode of the previous switching cycle by the feedback regulation mode of the same switching cycle, and when the switching cycle is a starting cycle, the target duration corresponding to the feedback regulation mode in the starting cycle can be a preset duration. It can be understood that in this embodiment, the next turn-on target switch tube in step 120 can also be turned on in the next resonant cycle in the current switching cycle.

[0222] The following describes a method for determining the operating mode corresponding to the switching cycle during the operation of the switching power supply.

[0223] In some embodiments, when the target switch is a compensation switch, the operating mode is determined based on the first square wave signal;

[0224] When the target switch tube is a freewheeling switch tube, the operating mode is determined based on the second square wave signal.

[0225] In this embodiment, the first square wave signal is generated based on an inverted signal of a gate drive voltage logic control signal of the primary-side switch tube.

[0226] The gate drive voltage logic control signal of the primary side switch tube is a logic control signal of a sampling signal of the gate drive voltage of the primary side switch tube.

[0227] During the actual execution process, when the sampling signal is 0, the gate drive voltage logic control signal is at a low level (logic 0); when the sampling signal is not 0, the gate drive voltage logic control signal is at a high level (logic 1); the high and low levels of the inverted signal of the gate drive voltage logic control signal of the primary side switch tube are opposite to those of the gate drive voltage logic control signal of the primary side switch tube.

[0228] The gate drive voltage of the primary side switch tube controls the conduction and shutdown of the primary side switch tube; when the gate drive voltage of the primary side switch tube is at a high level, the primary side switch tube is controlled to be turned on; when the gate drive voltage of the primary side switch tube is at a low level, the primary side switch tube is controlled to be turned on and off.

[0229] During the actual execution process, when the target switch tube is a compensation switch tube, the high and low levels of the first square wave signal can be determined based on the inverted signal of the gate drive voltage logic control signal of the primary switch tube, and the working mode can be determined based on the high and low levels of the first square wave signal; the high and low levels of the first square wave signal are different, and the corresponding working modes are different.

[0230] The second square wave signal is generated based on the inverted signal of the rising edge pulse signal of the freewheeling conduction logic control signal of the freewheeling switch tube.

[0231] The freewheeling conduction logic control signal is a logic control signal of a gate drive voltage signal of the freewheeling switch tube; and the gate drive voltage signal of the freewheeling switch tube is a sampling signal of the gate drive voltage of the freewheeling switch tube.

[0232] During the actual execution process, when the gate drive voltage signal of the freewheeling switch tube is 0, the freewheeling conduction logic control signal is a low level (logic 0); when the gate drive voltage signal of the freewheeling switch tube is not 0, the freewheeling conduction logic control signal is a high level (logic 1).

[0233] The freewheeling signal in the gate drive voltage signal of the freewheeling switch tube controls the conduction and shutdown of the freewheeling switch tube to enter and exit the freewheeling conduction control stage; when the freewheeling conduction logic control signal is at a high level, the freewheeling switch tube is turned on and enters the freewheeling conduction control stage; when the freewheeling conduction logic control signal is at a low level, the freewheeling switch tube is turned off and exits the freewheeling conduction control stage.

[0234] The rising edge pulse signal of the freewheeling conduction logic control signal has the same rising edge as the freewheeling conduction logic control signal, and the pulse width is smaller than the pulse signal of the freewheeling conduction logic control signal. The high and low levels of the inverted signal of the rising edge pulse signal of the freewheeling conduction logic control signal are opposite to those of the rising edge pulse signal of the freewheeling conduction logic control signal.

[0235] During the actual execution process, when the target switch tube is a freewheeling switch tube, the high and low levels of the second square wave signal can be determined based on the inverted signal of the gate drive voltage signal of the freewheeling switch tube, and the working mode can be determined based on the high and low levels of the second square wave signal. The high and low levels of the second square wave signal are different, and the corresponding working modes are different.

[0236] It is understandable that when the target switch tube is different, that is, the actual circuit structure is different, the square wave signal based on which the working mode is determined is different, and the high and low levels of the square wave signal are different, corresponding to different working modes.

[0237] According to the control method of the switching power supply provided in the embodiment of the present application, by determining the operating mode based on the first square wave signal when the target switching tube is a compensation switching tube, and determining the operating mode based on the second square wave signal when the target switching tube is a freewheeling switching tube, multiple methods of determining the operating mode can be implemented for various target switching tube situations, providing flexibility, applicability and accuracy in determining the operating mode.

[0238] In some embodiments, the first square wave signal is generated based on the inverted signal of the gate drive voltage logic control signal of the primary-side switch tube, and may include:

[0239] Counting the number of high-level times of the inverted signal of the gate drive voltage logic control signal starting from 0, and setting the first square wave signal to a high level when the number of high-level times reaches a first preset value;

[0240] When the next high level of the inverted signal of the gate drive voltage logic control signal arrives, the first square wave signal is set to a low level, and the number of high levels of the inverted signal of the gate drive voltage logic control signal is counted again from 0.

[0241] In this embodiment, the first preset value may be a count value of a preset switching cycle.

[0242] The first preset value can be customized by the user. For example, the first preset value can be set to a value such as 1, 32, 64 or 256. Of course, in other embodiments, the first preset value can also be set to other values, which is not limited in this application.

[0243] Based on the above embodiments, it can be seen that the time interval between one rising edge and the next rising edge of the inverted signal of the gate drive voltage logic control signal is one switching cycle.

[0244] It can be understood that the number of high levels of the inverted signal of the gate drive voltage logic control signal is counted starting from 0, that is, the switching cycles are counted starting from 0. When the count reaches a first preset value, the first square wave signal is set to a high level, and at the moment when the next high level of the inverted signal of the gate drive voltage logic control signal arrives, that is, at the moment of entering the next switching cycle, the first square wave signal is set to a low level, and the number of high levels of the inverted signal of the gate drive voltage logic control signal is counted again from 0, that is, the switching cycles are counted, thereby obtaining a first square wave signal with high and low levels, and the high and low levels accurately correspond to the switching cycles, so as to determine the working mode in each switching cycle based on the high and low levels of the first square wave signal in each switching cycle.

[0245] According to the control method of the switching power supply provided in the embodiment of the present application, by counting the high level times of the inverted signal of the gate drive voltage logic control signal from 0, when the high level times reach a first preset value, the first square wave signal is set to a high level, and when the next high level of the inverted signal of the gate drive voltage logic control signal arrives, the first square wave signal is set to a low level, and the high level times of the inverted signal of the gate drive voltage logic control signal are counted again from 0, the high and low levels of the first square wave signal can be accurately controlled, and the high and low levels of the first square wave signal can be accurately corresponded to each switching cycle to achieve accurate control of the working mode conversion of each switching cycle, thereby improving the accuracy and reliability of controlling the intervention frequency of the feedback regulation mode when the target switching tube is a compensation switching tube.

[0246] In some embodiments, the second square wave signal is generated based on the inverted signal of the rising edge pulse signal of the freewheeling conduction logic control signal of the freewheeling switch tube, and may include:

[0247] Counting the number of high-level times of the inverted signal of the rising edge pulse signal from 0, and setting the second square wave signal to a high level when the number of high-level times reaches a second preset value;

[0248] At the end of the current high level of the inverted signal of the rising edge pulse signal, the second square wave signal is set to a low level, and the number of high level times of the inverted signal of the rising edge pulse signal is counted again from 0.

[0249] In this embodiment, the second preset value may be a count value of a preset switching cycle.

[0250] The second preset value is similar to the first preset value and can be customized by the user. For example, the second preset value can be set to a value such as 1, 32, 64 or 256. Of course, in other embodiments, the second preset value can also be set to other values, which is not limited in this application.

[0251] In some embodiments, the second preset value may be the same as the first preset value.

[0252] Based on the above embodiments, it can be known that the time interval between one falling edge and the next falling edge of the inverted signal of the rising edge pulse signal of the freewheeling conduction logic control signal is one switching cycle.

[0253] It can be understood that the number of high levels of the inverted signal of the rising edge pulse signal is counted starting from 0, that is, the switching cycles are counted starting from 0, and when the count reaches a second preset value, the second square wave signal is set to a high level, and at the end of the current high level of the inverted signal of the rising edge pulse signal, that is, at the moment of entering the next switching cycle, the second square wave signal is set to a low level, and the number of high levels of the inverted signal of the rising edge pulse signal is counted again from 0, that is, the switching cycles are counted, thereby obtaining a second square wave signal with high and low levels, and the high and low levels precisely correspond to the switching cycles, so as to determine the working mode in each switching cycle based on the high and low levels of the second square wave signal in each switching cycle.

[0254] According to the control method of the switching power supply provided in the embodiment of the present application, by counting the high level times of the inverted signal of the rising edge pulse signal starting from 0, when the high level times reach a second preset value, the second square wave signal is set to a high level, and at the end moment of the current high level of the inverted signal of the rising edge pulse signal, the second square wave signal is set to a low level, and the high level times of the inverted signal of the rising edge pulse signal are counted again from 0, the high and low levels of the second square wave signal can be accurately controlled, and the high and low levels of the second square wave signal can be accurately corresponded to each switching cycle to achieve accurate control of the working mode conversion of each switching cycle, thereby improving the accuracy and reliability of the control of the intervention frequency of the feedback regulation mode when the target switching tube is a freewheeling switching tube.

[0255] In some embodiments, determining the operating mode based on the first square wave signal; determining the operating mode based on the second square wave signal may include:

[0256] When the first square wave signal or the second square wave signal is at a low level, determining the operating mode to be a compensation conduction mode;

[0257] When the first square wave signal or the second square wave signal is at a high level, the operating mode is determined to be the feedback regulation mode.

[0258] In this embodiment, it can be understood that when the target switching tube is a compensation switching tube, when the first square wave signal is at a low level within a switching cycle, it can be determined that the corresponding working mode within the switching cycle is the compensation conduction mode; when the first square wave signal is at a high level within a switching cycle, it can be determined that the corresponding working mode within the switching cycle is the feedback regulation mode.

[0259] When the target switch tube is a freewheeling switch tube, when the second square wave signal is at a low level within a switching cycle, it can be determined that the corresponding working mode within the switching cycle is the compensation conduction mode; when the second square wave signal is at a high level within a switching cycle, it can be determined that the corresponding working mode within the switching cycle is the feedback regulation mode.

[0260] It can be understood that the working mode can be made to correspond to the high and low levels of the first square wave signal and the second square wave signal, so that the frequency of the high levels of the first square wave signal and the second square wave signal can be controlled by controlling the size of the first preset value and the second preset value in the above embodiment, thereby more accurately controlling the intervention frequency of the feedback adjustment mode.

[0261] According to the control method of the switching power supply provided in the embodiment of the present application, by determining that the operating mode is the compensation conduction mode when the first square wave signal or the second square wave signal is at a low level, and determining that the operating mode is the feedback regulation mode when the first square wave signal or the second square wave signal is at a high level, it is possible to determine the corresponding operating mode based on the high and low levels of the first square wave signal or the second square wave signal within each switching cycle, and based on the operating modes corresponding to the high and low levels, the conversion rules of each operating mode can be controlled accordingly, thereby better maintaining the safety and stability of the system operation.

[0262] The embodiment of the present application also provides a control system for a switching power supply.

[0263] like Figure 11 As shown, in this embodiment, the control system includes: a transformer, a primary switch connected to the primary side of the transformer, a freewheeling switch connected to the secondary side of the transformer, a primary switch controller, and a secondary controller.

[0264] The primary switch controller is connected to the primary switch tube and is used to control the on / off state of the primary switch tube based on the drain voltage of the primary switch tube.

[0265] The secondary side switch controller is connected to the freewheeling switch tube and is used for freewheeling conduction control of the switching power supply.

[0266] The secondary side switch controller can also be used to control the on / off state of the freewheeling switch tube based on the target time and target duration.

[0267] When a compensation switch is connected between the primary switch and the ground, the primary switch controller can also be used to control the on / off state of the compensation switch based on the target time and target duration.

[0268] The target time is the time when the target switch tube is turned on.

[0269] The target switch tube is a freewheeling switch tube or a compensation switch tube connected between the primary switch tube and the ground.

[0270] The target time may include the time when the drain terminal voltage signal of the primary side switch tube reaches each resonance valley top during the free resonance process, or may include the time when the drain terminal voltage signal of the freewheeling switch tube reaches each resonance valley bottom during the free resonance process.

[0271] The target duration may be the duration after the last feedback regulation mode adjustment or the duration in the last compensation conduction mode.

[0272] In some embodiments, when the target switch is turned on for the first time, the target duration may be a preset duration, which may be roughly set based on test data and is not limited here.

[0273] During actual implementation, the primary side switch controller or the secondary side switch controller can control the on / off state of the target switch tube based on the target time and target duration, thereby realizing the compensation conduction mode and feedback regulation mode described in the above-mentioned switching power supply control method.

[0274] Among them, when a compensation switching tube is connected between the primary switching tube and the ground, the primary switching tube can also be used to, in the compensation conduction mode, determine the target duration as the target duration corresponding to the next time the compensation switching tube is turned on; in the feedback regulation mode, based on the target drain voltage and the target voltage range, adjust the target duration, and determine the adjusted target duration as the target duration corresponding to the next time the compensation switching tube is turned on.

[0275] The secondary side switch controller can also be used to, in the compensation conduction mode, determine the target duration as the target duration corresponding to the next time the freewheeling switch tube is turned on; in the feedback regulation mode, adjust the target duration based on the target drain voltage and the target voltage range, and determine the adjusted target duration as the target duration corresponding to the next time the freewheeling switch tube is turned on.

[0276] When the target switch is a compensation switch, the target drain voltage is the voltage at the first resonance valley that appears after the drain voltage of the primary switch recovers to a free resonance state after the compensation switch is turned off.

[0277] When the target switch is a freewheeling switch, the target drain voltage is the voltage at the first resonance valley peak that appears after the drain voltage of the freewheeling switch recovers to a free resonance state after the freewheeling switch is turned off.

[0278] It can be understood that the primary switch controller, on the basis of controlling the on-off state of the primary switch tube, can also control the on-off state of the compensation switch tube based on the target time and target duration when realizing zero voltage turn-on of the primary switch tube based on the compensation switch tube, thereby injecting energy into the drain voltage of the primary switch tube to realize zero voltage turn-on of the switching power supply, and in the feedback regulation mode, the target duration can be adjusted based on the target drain voltage and the target voltage range, thereby improving the zero voltage turn-on effect.

[0279] On the basis of controlling the on-off state of the freewheeling switch tube to realize the freewheeling conduction control of the switching power supply, the secondary side switch controller can also control the on-off state of the freewheeling switch tube based on the target time and target duration when realizing the zero voltage conduction of the primary side switch tube based on the freewheeling switch tube, thereby injecting energy into the drain voltage of the primary side switch tube to realize the zero voltage conduction of the switching power supply, and in the feedback regulation mode, the target duration can be adjusted based on the target drain voltage and the target voltage range, thereby improving the zero voltage conduction effect.

[0280] Among them, the freewheeling conduction control does not conflict with the zero-voltage conduction control of the primary side switch tube based on the freewheeling switch tube. The two control methods are staggered during the actual implementation process, that is, the two control methods based on controlling the on and off states of the freewheeling switch tube to achieve different functions do not overlap in the execution time.

[0281] According to the control system of the switching power supply provided in the embodiment of the present application, by setting a transformer, a primary switch tube connected to the primary side of the transformer, a freewheeling switch tube connected to the secondary side of the transformer, a primary switch controller connected to the primary switch tube and a secondary switch controller connected to the freewheeling switch tube, and a compensation switch tube connected between the primary switch tube and the ground, it is possible to control the on-off state of the target switch tube based on the target time and target duration, and control the on-off state of the primary switch tube based on the drain voltage signal of the primary switch tube, thereby realizing a compensation conduction mode for achieving zero voltage conduction, and for adjusting The target duration is used to adjust the feedback regulation mode of the zero voltage turn-on effect, so that in the actual execution process, the compensation turn-on mode and the feedback regulation mode can be alternately performed at a certain time interval to achieve adaptive adjustment of the target duration, thereby achieving adaptive adjustment of the zero voltage turn-on effect, improving the accuracy and reliability of zero voltage turn-on control, thereby further reducing the switching power supply loss and improving system efficiency; and by multiplexing the on and off states of the freewheeling switch tube to achieve zero voltage turn-on control, the compatibility and adaptability of the zero voltage turn-on control can be improved, and there is no need to design a complex controller, saving design costs.

[0282] In some embodiments, the primary side switch controller may include:

[0283] The main power tube conduction control module is used to control the on / off state of the primary side switch tube based on the drain terminal voltage of the primary side switch tube;

[0284] A first conduction timing control unit, wherein an input end of the first conduction timing control unit is connected to an output end of the main power tube conduction control module, and another input end of the first conduction timing control unit is used to receive a drain terminal voltage signal of the primary side switch tube for determining a target timing;

[0285] a first feedback regulation unit, wherein an input end of the first feedback regulation unit is respectively connected to an output end of the main power tube conduction control module and an output end of the first conduction timing control unit; another input end of the first feedback regulation unit is used to receive a drain terminal voltage signal of the primary side switch tube, so as to determine a target duration corresponding to the next conduction of the target switch tube; and an output end of the first feedback regulation unit is connected to an input end of the first conduction timing control unit;

[0286] A first on-time control unit, wherein the input end of the first on-time control unit is respectively connected to the output end of the first on-time control unit and the output end of the first feedback adjustment unit, and is used to control the on-off state of the compensation switch tube based on the target time and the target duration corresponding to the current switching cycle.

[0287] In this embodiment, the drain voltage signal of the primary switching tube is a sampling signal of the drain voltage of the primary switching tube, or a sampling signal of a transformed waveform that can reflect the drain voltage characteristics or some key characteristics of the primary switching tube.

[0288] For example, the resonance valley top of the drain voltage of the primary side switch tube, the distance between the resonance valley top voltage and the platform voltage, the resonance valley bottom, the distance between the resonance valley bottom voltage and the platform voltage, etc. are not limited in this application.

[0289] It can be understood that the main power tube conduction control module is used to control the on-off state of the primary side switch tube to retain the traditional functions and control logic of the switching power supply; the first conduction time control unit, the first feedback adjustment unit and the first conduction duration control unit are used to control the on-off state of the compensation switch tube when the target switch tube is the compensation switch tube to achieve zero voltage conduction control of the primary side switch tube.

[0290] like Figure 5 As shown, in the actual implementation process, the main power tube conduction control module realizes the conduction and shutdown of the primary side switch tube QP according to the system output power demand. Since it works in the quasi-resonant mode, the main power tube conduction control module controls QP to be turned on at the bottom of the Nvalley. DRV is the logic control signal corresponding to the gate drive voltage signal DRVP of QP. In order to ensure circuit safety, the main power tube conduction control module will output the first enable signal EN to control whether the first conduction time control unit, the first feedback adjustment unit and the first conduction duration control unit are working. Among them, the first enable signal will only be logic 1 (high level) when the system is in the valley lock state and in the free resonance stage of the system, that is, at this time, the first conduction time control unit, the first feedback adjustment unit and the first conduction duration control unit will work.

[0291] The drain voltage signal VDP_SNS of the primary-side switch tube is a key signal for compensation conduction control. The first conduction moment control unit, the first feedback adjustment unit, and the first conduction duration control unit generate the compensation switch tube conduction control signal DRVCMP based on the VDP_SNS information, EN, DRV, and Nvalley control signals. This signal is used to drive the conduction compensation switch tube QCMP to achieve zero-voltage conduction of the primary-side switch tube.

[0292] It can be understood that, in the actual implementation process, based on the first conduction moment control unit, the first feedback adjustment unit and the first conduction duration control unit, the compensation conduction mode and the feedback adjustment mode in the control method of the above-mentioned switching power supply can be realized when the target switch tube is a compensation switch tube.

[0293] like Figure 6As shown, in the actual implementation process, the first conduction moment control unit determines the conduction position of the compensation switch tube QCMP based on the VDP_SNS information, EN, DRV, Nvalley and the first control signal CMP_PLS, and the first conduction control signal ON_Trig outputted by it is used as the input signal of the first conduction duration control unit. This signal is used to trigger the conduction of the compensation switch tube QCMP, and the first comparison signal PeakOK is used to assist the first feedback adjustment unit to adjust the target duration.

[0294] The first control signal CMP_PLS is a compensation pulse output by the first feedback regulation unit. The appearance of this pulse indicates that the current switching cycle is in the feedback regulation mode. At this time, the first conduction timing control unit will turn on the compensation switch QCMP one resonant cycle in advance.

[0295] The first feedback regulation unit adjusts the interval timing and target duration of the feedback regulation mode intervention based on the VDP_SNS information, DRV and PeakOK. The second conduction control signal Vton it outputs serves as the input signal of the first conduction duration control unit. Vton determines the target duration TZVS_ON of the compensation switch tube.

[0296] When the first on-time control unit receives the rising edge of the first on-control signal ON_Trig, it starts to turn on the compensation switch tube QCMP (that is, a rising edge appears in DRVCMP), and controls the on-time of the compensation switch tube QCMP according to the high-level time of the second on-control signal Vton (that is, the high-level duration of DRVCMP, that is, the target duration).

[0297] According to the control system of the switching power supply provided in the embodiment of the present application, by setting a primary side switch controller including a main power tube conduction control module, a first conduction time control unit, a first feedback adjustment unit and a first conduction duration control unit, it is possible to achieve, when the target switch tube is a compensation switch tube, retaining the traditional functions and control logic of the switching power supply, and realizing, when the target switch tube is a compensation switch tube, the determination of the target time and target duration corresponding to the compensation conduction mode and the feedback adjustment mode, and based on the determined target time and target duration, controlling the on-off state of the compensation switch tube in different working modes to achieve the functional effects corresponding to each working mode.

[0298] In some embodiments, the first conduction timing control unit may include:

[0299] A first valley detection circuit, wherein the input end of the first valley detection circuit is used to receive the drain terminal voltage signal of the primary side switch tube, and the output end of the first valley detection circuit is used to output a first pulse signal;

[0300] a first logic OR operator, wherein a first input terminal of the first logic OR operator is connected to the output terminal of the first valley detection circuit, and a second input terminal of the first logic OR operator is used to receive a first control signal;

[0301] a first counter, wherein the third input terminal of the first counter is connected to the output terminal of the first logical OR operator, and the fourth input terminal is used to receive the gate drive voltage logic control signal of the primary side switch tube; the output terminal of the first counter is used to output the valley top count value of the resonance valley top of the drain terminal voltage signal of the primary side switch tube during the free resonance process; in the current switching cycle, when the gate drive voltage logic control signal of the primary side switch tube has a rising edge, the valley top count value is cleared;

[0302] a first digital comparator, wherein the fifth input terminal of the first digital comparator is connected to the output terminal of the first counter, and the sixth input terminal is used to receive a target valley signal; the target valley signal is used to represent the number of valleys at the target moment; and the output terminal of the first digital comparator is used to output a first comparison signal;

[0303] A first rising edge pulse generator, wherein an input terminal of the first rising edge pulse generator is connected to an output terminal of the first digital comparator;

[0304] a first logic AND operator, wherein the seventh input terminal of the first logic AND operator is connected to the output terminal of the first rising edge pulse generator, and the eighth input terminal is used to receive the first enable signal; and the output terminal of the first logic AND operator is used to output the first conduction control signal;

[0305] In this embodiment, the short-term high-level signal included in the first pulse signal is used to represent the resonance valley of the drain-end voltage signal of the primary-side switching tube during the free resonance process.

[0306] The first square wave signal is generated based on the inverted signal of the gate drive voltage logic control signal of the primary side switch tube and is used to determine the target time.

[0307] The first control signal is a pulse signal generated after the rising edge of the first square wave signal is delayed, and is used to determine the second resonant valley top of the drain terminal voltage signal of the primary side switching tube in the free resonance process as the target valley top when the working mode of the current switching cycle is the feedback regulation mode.

[0308] The first comparison signal is used to determine whether the drain voltage signal of the primary-side switch tube reaches a target valley peak in the current switching cycle.

[0309] The first enable signal is used to control whether the first conduction moment control unit, the first feedback adjustment unit, and the first conduction duration control unit are working.

[0310] The rising edge time of the first conduction control signal is used to represent the target time.

[0311] like Figure 7 As shown, in the actual implementation process, the first valley detection circuit detects the resonance valley of the drain voltage of the primary side switch tube in the free resonance process according to the drain voltage signal VDP_SNS of the primary side switch tube, and outputs a short high-level signal (pulse) of the first pulse signal Peak each time the resonance valley is detected. The first pulse signal Peak and the first control signal CMP_PLS are input to the OR gate (first logic OR operator), and after the OR operation, the valley count pulse signal PeakPLS is output. PeakPLS is connected to the CLK input terminal of the first counter. The first counter counts the number of PeakPLS pulses and outputs the valley count value PeakCnt at its output terminal; the RST input terminal of the first counter is connected to the gate drive voltage logic control signal DRV of the primary side switch tube. When DRV is logic 1 (a rising edge occurs), that is, when entering the next switching cycle, the valley count value PeakCnt will be cleared.

[0312] The valley count value PeakCnt and Nvalley control signal are connected to the INA and INB input terminals of the first digital comparator, respectively. When the valley count value PeakCnt and Nvalley (the number of valley tops of the target valley) are equal, the first comparison signal PeakOK output by the first digital comparator will be set to 1 (set to 1 means set to a high level; set to 0 means set to a low level). The first comparison signal PeakOK is connected to the input terminal of the first rising edge pulse generator. When the rising edge of the first comparison signal PeakOK arrives, the pulse signal ON_PLS will be output. The pulse signal ON_PLS and the first enable signal EN are respectively connected to the input terminals of the AND gate (first logical AND operator). After the AND operation, the first conduction control signal ON_Trig is output.

[0313] It can be understood that in the feedback regulation mode, due to the influence of the first control signal CMP_PLS, the valley count value PeakCnt will be 1 greater than the actual value, so that the compensation switch tube can be turned on at the Nvalley-1th valley in the feedback regulation mode; in the compensation conduction mode, the compensation switch tube will be turned on at the Nvalleyth valley top position according to design expectations.

[0314] It should be noted that when Nvalley=1, due to the control of the first enable signal EN, when the current switching cycle is in the feedback regulation mode, the compensation switch tube will not be turned on, thereby ensuring circuit safety.

[0315] According to the control system of the switching power supply provided in the embodiment of the present application, by providing a first valley detection circuit, a first logic OR operator, a first counter, a first digital comparator, a first rising edge pulse generator and a first logic AND operator, it is possible to determine the corresponding different target moments when each switching cycle is in a compensation conduction mode or a feedback regulation mode based on the target valley, the first control signal, the gate drive voltage logic control signal of the primary switching tube and the resonant valley of the drain terminal voltage of the primary switching tube obtained by real-time counting, thereby improving the reliability of the control system.

[0316] In some embodiments, the first feedback adjustment unit may include:

[0317] A second counter, wherein the input end of the second counter is used to receive an inverted signal of the gate drive voltage logic control signal of the primary side switch tube;

[0318] a second logic AND operator, wherein the input end of the second logic AND operator is connected to the output end of the second counter, and the output end of the second logic AND operator is used to output the first square wave signal;

[0319] The first rising edge delayed pulse generator has an input end connected to the output end of the second logic AND operator; and an output end of the first rising edge delayed pulse generator is used to output a first control signal.

[0320] In this embodiment, if Figure 8 As shown, in the actual implementation process, the CLK input terminal of the second counter inputs the inverted signal DRVb of the gate drive voltage logic control signal of the primary side switch tube, and the second counter counts the number of high-level signals of DRVb, thereby realizing the counting of the number of switching cycles, and its count value is output through its output terminal Q<Q7Q6…Q0> Output.

[0321] The output of the second counter is connected to the input of AND gate 1 (second logical AND operator). When the count value of the second counter reaches the first preset value, the first square wave signal TimeOut output by AND gate 1 will be set to 1. The period when TimeOut is 1 indicates that the system is in feedback regulation mode. TimeOut is connected to the input of the first rising edge delay pulse generator. When the rising edge of TimeOut arrives, the first rising edge delay pulse generator will delay for a period of time (such as 100nS) and output the first control signal CMP_PLS.

[0322] It can be understood that the first feedback adjustment unit including the second counter, the second logic AND operator and the first rising edge delay pulse generator can be used to time the interval between two feedback adjustment mode interventions; the interval between two feedback adjustment mode interventions defined in this embodiment is the first preset value.

[0323] In some embodiments, when the first preset value is 255, it can be considered that the feedback regulation mode is intervened once every 256 switching cycles. In the actual implementation process, a counter with a bit width of 8 can be selected as the second counter.

[0324] Of course, in other embodiments, if other interval periods of the intervention feedback adjustment mode are selected, a counter with an appropriate bit width may be selected accordingly. This application does not limit this. When the second counter is full, it will restart counting from 0.

[0325] According to the control system of the switching power supply provided in the embodiment of the present application, by providing a first feedback adjustment unit including a second counter, a second logic AND operator, and a first rising edge delay pulse generator, it is possible to effectively obtain the first control signal for generating the target moment, thereby improving the reliability of the control system.

[0326] In some embodiments, the first feedback adjustment unit may further include:

[0327] a first comparator, wherein a ninth input terminal of the first comparator is used to receive a drain voltage signal of the primary-side switch tube, and a tenth input terminal of the first comparator is used to receive a first threshold voltage; an output terminal of the first comparator is used to output a first logic signal, wherein a high-level time of the first logic signal indicates that the drain voltage signal is greater than the first threshold voltage;

[0328] a second comparator, wherein the eleventh input terminal of the second comparator is used to receive the second threshold voltage, and the twelfth input terminal of the second comparator is used to receive the drain voltage signal of the primary-side switch tube; the output terminal of the second comparator is used to output a second logic signal, and the high level time of the first logic signal indicates that the drain voltage signal is less than the second threshold voltage;

[0329] a first valley detection circuit, wherein the input end of the first valley detection circuit is used to receive the drain terminal voltage signal of the primary side switching tube, and the output end of the first valley detection circuit is used to output a fourth pulse signal, wherein the short-term high-level signal included in the fourth pulse signal is used to represent the resonance valley of the drain terminal voltage signal of the primary side switching tube during the free resonance process;

[0330] a third logical AND operator, wherein a thirteenth input terminal of the third logical AND operator is connected to the output terminal of the first comparator, a fourteenth input terminal is used to receive the first square wave signal, a fifteenth input terminal is used to receive the first comparison signal, and a sixteenth input terminal is connected to the output terminal of the first valley detection circuit; the output terminal of the third logical AND operator is used to output a second comparison signal, and the high level time of the second comparison signal indicates that the target drain terminal voltage is greater than the first threshold voltage;

[0331] a fourth logical AND operator, wherein a seventeenth input terminal of the fourth logical AND operator is connected to the output terminal of the second comparator, an eighteenth input terminal is used to receive the first square wave signal, a nineteenth input terminal is used to receive the first comparison signal, and a twentieth input terminal is connected to the output terminal of the first valley detection circuit; the output terminal of the fourth logical AND operator is used to output a third comparison signal, and a high-level time of the third comparison signal indicates that the target drain terminal voltage is less than the second threshold voltage;

[0332] a first bidirectional counter, wherein a twenty-first input terminal of the first bidirectional counter is connected to the output terminal of the third logical AND operator, and a twenty-second input terminal of the first bidirectional counter is connected to the output terminal of the fourth logical AND operator; the output terminal of the first bidirectional counter is used to output a first count value, and an increase or decrease in the first count value represents an increase or decrease in the target duration;

[0333] a first DAC circuit, wherein an input terminal of the first DAC circuit is connected to an output terminal of the first bidirectional counter;

[0334] The first limiting circuit has an input end connected to the output end of the first DAC circuit, and the output end of the first limiting circuit is used to output a second conduction control signal, and the high level duration of the second conduction control signal represents the target duration.

[0335] In this embodiment, if Figure 9 As shown, in the actual implementation process, the non-inverting input terminal of comparator 1 (first comparator) is connected to the drain voltage signal VDP_SNS of the primary side switch tube, and the reverse input terminal is connected to the first threshold voltage VTH_H. When VDP_SNS is greater than VTH_H, the first logic signal GE output by comparator 1 is set to 1.

[0336] The input end of the first valley detection circuit is connected to the drain voltage signal VDP_SNS of the primary-side switching tube. Whenever the resonant valley bottom of the drain voltage of the primary-side switching tube is reached, the output end of the first valley detection circuit will output a pulse of the fourth pulse signal Valley (a short-term high-level signal); the first logic signal GE, the first square wave signal TimeOut, the first comparison signal PeakOk and the fourth pulse signal Valley are connected to the input end of the AND gate 2 (the third logic AND operator), and after the AND operation, the pulse signal UP_CLK is output. UP_CLK is connected to the UP input end of the first bidirectional counter as an upward counting pulse. For each UP_CLK pulse, the first count value T_Cnt of the first bidirectional counter is increased by 1; the appearance of UP_CLK indicates that the current compensation energy of the system is too small, and the compensation on-time needs to be increased.

[0337] The non-inverting input of comparator 2 (the second comparator) is connected to the second threshold voltage VTH_L, and the inverting input is connected to the drain voltage signal VDP_SNS of the primary side switch tube. When VDP_SNS is less than VTH_L, the second logic signal LE output by comparator 2 is set to 1; the second logic signal LE, the first square wave signal TimeOut, the first comparison signal PeakOk and the fourth pulse signal Valley are connected to the input of AND gate 3 (the fourth logic AND operator), and after the AND operation, the pulse signal DOWN_CLK is output. DOWN_CLK is connected to the DOWN input of the first bidirectional counter as a down counting pulse. For each DOWN_CLK pulse, the first count value T_Cnt of the first bidirectional counter is reduced by 1; the appearance of DOWN_CLK represents the current compensation energy redundancy of the system, and the compensation on-time needs to be reduced.

[0338] It should be noted that the first bidirectional counter has an anti-overflow function, that is, when the first count value T_Cnt decreases to 0, the DOWN_CLK pulse occurs again, and the first count value remains unchanged; when the first count value T_Cnt increases to the maximum count value, the UP_CLK pulse occurs again, and the first count value remains unchanged; and a certain preset value can be set when the first bidirectional counter is powered on to ensure that the target duration TZVS_ON time when the system starts working is not 0 (that is, the target duration of the initial switching cycle can be the preset duration), thereby shortening the time it takes for the system to reach a steady state.

[0339] The first count value T_Cnt is connected to the input end of the first DAC circuit. The first DAC circuit implements digital-to-analog conversion, that is, the size of its output voltage VT is determined according to the first count value T_Cnt. The first count value T_Cnt is directly proportional to VT. The minimum resolution of the DAC will determine the minimum step size of the target time length TZVS_ON time adjustment.

[0340] The voltage VT is connected to the input end of the limiting circuit. The limiting circuit clamps the voltage VT up and down and then outputs a compensation voltage, namely the second conduction control signal Vton. The voltage VT affects the target duration of the compensation switch tube. Therefore, clamping the voltage VT up and down is to limit the target duration to a maximum and minimum duration, thereby improving the stability and safety of the circuit.

[0341] According to the control system of the switching power supply provided in the embodiment of the present application, by providing a first comparator, a second comparator, a first valley detection circuit, a third logic AND operator, a fourth logic AND operator, a first bidirectional counter, a first DAC circuit and a first limiting circuit, it is possible to implement, when the target switching tube is a compensation switching tube, the control logic for adjusting the target duration corresponding to the next switching cycle based on the relationship between the target drain voltage and the first threshold voltage and the second threshold voltage, thereby improving the reliability of the control system.

[0342] In some embodiments, the first feedback adjustment unit may include:

[0343] a first timing circuit, the first timing circuit being configured to generate a first square wave signal;

[0344] a first resonant period conduction control unit, wherein the input end of the first resonant period conduction control unit is connected to the output end of the first timing circuit, and is used to determine the target valley top at the target time;

[0345] a first sampling and holding circuit, wherein an input terminal of the first sampling and holding circuit is connected to an output terminal of the first resonant period conduction control unit; a first output terminal of the first sampling and holding circuit is used to output a third logic signal, and when the first sampling and holding circuit completes sampling the target drain terminal voltage, the third logic signal is set to a high level; and a second output terminal of the first sampling and holding circuit is used to output the target drain terminal voltage;

[0346] a third rising edge pulse generator, wherein the input end of the third rising edge pulse generator is connected to the first output end, and the output end of the third rising edge pulse generator is used to output a second pulse signal, wherein the second pulse signal is a pulse signal having the same rising edge as the third logic signal;

[0347] a first subtraction circuit, wherein a twenty-third input terminal of the first subtraction circuit is connected to the second output terminal, a twenty-fourth input terminal is used to receive the third threshold voltage, and an output terminal of the first subtraction circuit is used to output a first error signal, wherein the first error signal is used to represent a difference between the target drain terminal voltage and the third threshold voltage;

[0348] a second switch, one end of the second switch being connected to the output end of the first subtraction circuit, and the second pulse signal controlling the on / off state of the second switch;

[0349] a first PI controller, wherein an input end of the first PI controller is connected to the other end of the second switch;

[0350] The second amplitude limiting circuit has an input end connected to the output end of the first PI controller, and an output end of the second amplitude limiting circuit is used to output a second conduction control signal.

[0351] In this embodiment, if Figure 17 As shown, in the actual implementation process, the first timing circuit is used to time the interval between two feedback mode interventions. When the timing is reached, the first resonant cycle conduction control unit controls the compensation switch to be turned on one resonant cycle in advance in the current switching cycle.

[0352] Among them, if in the compensation conduction mode, the number of valley tops of the compensation switch tube (the number of valley tops of the target valley top) is Nvalley, then when the target switch tube is the compensation switch tube and the current switching cycle is in the feedback regulation mode, the compensation switch tube is turned on at the Nvalley-1th valley top.

[0353] The first sampling and holding circuit samples the voltage V of the subsequent resonant peak (compensation switch is turned on: the voltage at the bottom of the valley Nvalley-1 in this switching cycle) REF , and maintain; voltage V REF The first error signal V is generated by the first subtraction circuit ERR ; Among them, V ERR =V REF -V TH , V TH is the third threshold voltage; when the first sample and hold circuit finishes sampling, the third logic signal SampleOK output by it will be set to 1 and will be cleared when the next sampling starts.

[0354] The third logic signal SampleOK is connected to the third rising edge pulse generator. Whenever the third logic signal SampleOK reaches a rising edge, the third rising edge pulse generator circuit will output the second pulse signal TI.

[0355] The second pulse signal TI controls the on and off of the second switch S. The second switch S is turned on during the high level period of the second pulse signal TI, and is turned off during the low level period of the second pulse signal TI. When the second switch S is turned on, the first error signal V ERR As the input to the first PI controller.

[0356] In some embodiments, the first PI controller may include a first integration circuit, a first proportional amplifier circuit, and a first addition circuit. In actual implementation, when the second switch S is turned on, the first error signal V ERR As the input of the first integrator, the first integrator outputs the integration result voltage VI; the pulse width of the second pulse signal TI is the integration time of the first integrator; in addition, the first error signal V ERR It also serves as the input of the first proportional method circuit and outputs the proportional amplification result voltage VP; the voltages VI and VP serve as the input of the first adding circuit, implement the addition operation process and output the operation result voltage VFB; wherein, VFB=VI+VP, the VFB voltage serves as the input of the second limiting circuit, and after being clamped up and down by the second limiting circuit, the output voltage Vton (the second conduction control signal) is output.

[0357] In some embodiments, the first PI controller may also not include the first proportional amplifier circuit, that is, the system's final zero voltage turn-on can achieve the preset effect only through the first integration circuit, but the introduction of the first proportional amplifier circuit can shorten the time it takes for the system's zero voltage turn-on to achieve the preset effect.

[0358] According to the control system of the switching power supply provided in the embodiment of the present application, by providing a first timing circuit, a first resonant period conduction control unit, a first sampling and holding circuit, a third rising edge pulse generator, a first subtraction circuit, a second switch, a first PI controller and a first feedback adjustment unit of a second limiting circuit, it is possible to achieve PI control based on the difference between the target drain voltage and the third threshold voltage when the target switching tube is a compensation switching tube, so as to adjust the control logic for obtaining the target duration corresponding to the next switching cycle, thereby improving the reliability of the control system.

[0359] In some embodiments, the first feedback adjustment unit may include:

[0360] a second sample-and-hold circuit, wherein the twenty-fifth input terminal of the second sample-and-hold circuit is used to receive the second enable signal, and the twenty-sixth input terminal of the second sample-and-hold circuit is used to receive the drain voltage signal of the primary-side switch tube; the third output terminal of the second sample-and-hold circuit is used to output a fourth logic signal, and when the second sample-and-hold circuit completes sampling the target drain voltage, the fourth logic signal is set to a high level; and the fourth output terminal of the second sample-and-hold circuit is used to output the target drain voltage;

[0361] a fourth rising edge pulse generator, wherein the input end of the fourth rising edge pulse generator is connected to the third output end; the output end of the fourth rising edge pulse generator is used to output a third pulse signal, wherein the third pulse signal is a pulse signal having the same rising edge as the fourth logic signal;

[0362] a second subtraction circuit, wherein the twenty-seventh input terminal of the second subtraction circuit is connected to the fourth output terminal, the twenty-eighth input terminal of the second subtraction circuit is used to receive the third threshold voltage, and the output terminal of the second subtraction circuit is used to output a second error signal, the second error signal being used to represent a difference between the target drain terminal voltage and the third threshold voltage;

[0363] a third switch, one end of the third switch being connected to the output end of the second subtraction circuit, and the third pulse signal controlling the on / off state of the third switch;

[0364] a second PI controller, wherein an input end of the second PI controller is connected to the other end of the third switch;

[0365] The third amplitude limiting circuit has an input end connected to the output end of the second PI controller, and an output end of the third amplitude limiting circuit is used to output a second conduction control signal.

[0366] In this embodiment, it can be understood that the difference between this embodiment and the above embodiment is that the input of the sampling and holding circuit is different, and the remaining structure and control logic are similar to the above embodiment. This application will not go into details here. The input signal of the second sampling and holding circuit in this embodiment is described below.

[0367] like Figure 18 As shown, in the actual execution process, the second sampling and holding circuit receives the drain voltage signal V of the primary side switch tube DP_SNS And the second enable signal EN; the second enable signal EN is the enable logic control signal of the sample and hold circuit. When the second enable signal EN is in logic 1, the sample and hold circuit will sample V DP_SNS voltage and overwrites the previous sample-and-hold value.

[0368] It should be noted that this embodiment is applied to the scenario where the target switch tube is a compensation switch tube, and in the feedback regulation mode, it is not necessary to turn on the compensation switch tube one resonant cycle earlier than in the compensation conduction mode.

[0369] In some embodiments, the operating mode of each switching cycle may be a feedback regulation mode, thereby achieving a zero voltage turn-on effect of feedback on a switching cycle-by-switch cycle basis.

[0370] like Figure 19 As shown, in the actual implementation process, since the conduction valley and the specific conduction time of the primary side switch tube in a switching cycle are controlled by the primary side switch controller, the second enable signal EN can be set to 1 in the period before the primary side switch tube is turned on in the switching cycle, so that the voltage at the valley of the conduction of the primary side switch tube can be detected in each switching cycle, thereby realizing the effect of feedback regulation of zero voltage turn-on in each cycle.

[0371] According to the control system of the switching power supply provided in the embodiment of the present application, through the second sampling and holding circuit, the fourth rising edge pulse generator, the second subtraction circuit, the third switch, the second PI controller and the first feedback adjustment unit of the third limiting circuit, it can be achieved that when the target switching tube is a compensation switching tube, each switching cycle is in a feedback adjustment mode, so as to feedback the control logic of the zero voltage turn-on effect in each switching cycle, thereby improving the flexibility and reliability of the control system.

[0372] In some embodiments, the first on-time control unit may include:

[0373] Current source, the current source is used to output current;

[0374] a first switch connected in parallel with the current source, the first switch being controlled based on an inverted signal of a compensation switch tube conduction control signal, the compensation switch tube conduction control signal being used to control an on / off state of the compensation switch tube;

[0375] a first capacitor connected in parallel with the first switch;

[0376] a third comparator, wherein a twenty-ninth input terminal of the third comparator is used to receive the voltage across the first capacitor, and a thirtieth input terminal of the third comparator is used to receive the second conduction control signal;

[0377] a second rising edge pulse generator, wherein an input terminal of the second rising edge pulse generator is connected to an output terminal of the third comparator;

[0378] A trigger, wherein the thirty-first input terminal of the trigger is used to receive the first conduction control signal, and the thirty-second input terminal is connected to the output terminal of the second rising edge pulse generator; the output terminal of the trigger is used to output the compensation switch tube conduction control signal.

[0379] In this embodiment, the trigger may be an SR trigger.

[0380] like Figure 10 As shown, in the actual implementation process, the first conduction control signal ON_trig output by the first conduction moment control unit is connected to the S input terminal of the SR trigger. Whenever the rising edge of the first conduction control signal ON_trig arrives, the compensation switch tube conduction control signal DRV output by the Q output terminal of the SR trigger CMP Set to 1; the signal DRV output from the QN terminal of the SR trigger CMPb To compensate for the switch conduction control signal DRV CMP The inverted signal.

[0381] Among them, the compensation switch conduction control signal DRV CMP It can be used as the driving signal of the gate of the compensation switch tube directly or after driving and amplifying (direct driving method can be used, that is, the compensation switch tube conduction control signal DRV CMP Directly control the on / off state of the compensation switch tube, and when the compensation switch tube conducts the control signal DRV CMP When the level is high, the compensation switch is turned on, otherwise it is turned off).

[0382] The current source outputs a current i, and the current i cooperates with the control of the first switch S to realize the charging and discharging of the first capacitor C; the first switch S is connected in parallel at both ends of the first capacitor C, and the conduction and shutdown of the first switch S are controlled by the signal DRV. CMPb Control, in DRV CMPb During the high level period, the first switch S is turned on, the first capacitor C is discharged, and the voltage Vchg across the first capacitor C is set to 0; CMPb After it reaches a low level, the first switch S is disconnected, and the current i charges the first capacitor C.

[0383] The voltage Vchg across the first capacitor C is connected to the non-inverting input of the third comparator, and the inverting input of the third comparator is connected to the second conduction control signal Vton. When Vchg is greater than Vton, the logic signal END output by the third comparator is set to 1, indicating that the target duration T of the conduction compensation switch represented by the second conduction control signal Vton is 1. ZVS_ON Has been reached, that is, the compensation switch tube has been turned on for the target duration T ZVS_ON .

[0384] The logic signal END is connected to the input terminal of the second rising edge pulse generator. Whenever the rising edge of the logic signal END arrives, the pulse signal OFF_Trig is output.

[0385] The pulse signal OFF_Trig is connected to the R input of the SR trigger. Whenever the pulse signal OFF_trig arrives, the Q output of the SR trigger outputs the signal DRV. CMP Set to 0 to turn off the compensation switch tube.

[0386] It can be understood that the second conduction control signal Vton is the feedback voltage of the system zero voltage conduction effect, which determines the target duration T of the system. ZVS_ON .

[0387] In some embodiments, based on the charging process of the first capacitor C, the target duration can be determined by the following formula:

[0388] T ZVS_ON =(C*Vton) / i

[0389] Among them, C and i are both certain values, which can be customized by the user based on engineering experience, and this application does not limit them here.

[0390] According to the control system of the switching power supply provided in the embodiment of the present application, by providing a current source, a first switch, a first capacitor, a third comparator, a second rising edge pulse generator and a first on-time control unit of a trigger, it is possible to implement control logic for controlling the on-off state of the compensation switch tube based on the target time and target duration when the target switch tube is a compensation switch tube, thereby improving the reliability of the control system.

[0391] In some embodiments, the secondary side switch controller may include:

[0392] A freewheeling conduction control module, used to control the freewheeling conduction of the switching power supply based on the drain voltage of the freewheeling switch tube;

[0393] A second conduction timing control unit, wherein an input end of the second conduction timing control unit is connected to the output end of the freewheeling conduction control module, and another input end of the second conduction timing control unit is used to receive a drain terminal voltage signal of the freewheeling switch tube for determining a target timing;

[0394] a second feedback regulation unit, wherein an input end of the second feedback regulation unit is respectively connected to an output end of the freewheeling conduction control module and an output end of the second conduction timing control unit; another input end of the second feedback regulation unit is used to receive a drain voltage signal of the freewheeling switch tube, so as to determine a target duration corresponding to the next conduction of the target switch tube; and an output end of the second feedback regulation unit is connected to an input end of the second conduction timing control unit;

[0395] A second on-time control unit, wherein the input end of the second on-time control unit is respectively connected to the output end of the second on-time control unit and the output end of the second feedback adjustment unit, and is used to control the on-off state of the freewheeling switch tube based on the target time and the target duration corresponding to the current switching cycle;

[0396] a second logic OR operator, wherein the input end of the second logic OR operator is respectively connected to the output end of the freewheeling conduction control module and the output end of the second conduction duration control unit;

[0397] A drive circuit, wherein the input end of the drive circuit is connected to the output end of the second logic OR operator, and the output end of the drive circuit is used to output a gate drive voltage signal of the freewheeling switch tube, which is used to control the freewheeling conduction of the freewheeling switch tube and control the on-off state of the freewheeling switch tube based on the target time and target duration.

[0398] In this embodiment, the freewheeling conduction control module is used to generate a freewheeling conduction logic control signal based on the waveform of the drain voltage of the freewheeling switch tube, and control the on-off state of the freewheeling switch tube to retain the traditional freewheeling function and freewheeling control logic of the switching power supply; the second conduction moment control unit, the second feedback adjustment unit and the second conduction duration control unit are used to control the on-off state of the freewheeling switch tube when the target switch tube is the freewheeling switch tube, so as to realize zero-voltage conduction control of the primary side switch tube; the second logic OR operator is used to make the freewheeling conduction control and zero-voltage conduction control of the freewheeling switch tube alternate; the drive circuit is used to control the on-off state of the freewheeling switch tube.

[0399] The drain terminal voltage signal of the freewheeling switch is a sampling signal of the drain terminal voltage of the freewheeling switch, or a sampling signal of a transformed waveform that can reflect the drain terminal voltage characteristics or some key characteristics of the freewheeling switch.

[0400] For example, the resonance valley top of the drain voltage of the freewheeling switch tube, the distance between the resonance valley top voltage and the platform voltage, the resonance valley bottom, the distance between the resonance valley bottom voltage and the platform voltage, etc. are not limited in this application.

[0401] like Figure 12As shown, in the actual implementation process, the freewheeling conduction control module realizes the conduction and shutdown of the freewheeling switch tube QS according to the drain terminal voltage of the freewheeling switch tube; the DRVM signal is the logic control signal (freewheeling conduction logic control signal) corresponding to the freewheeling conduction stage DRVS of the freewheeling switch tube.

[0402] In order to ensure circuit safety, the freewheeling conduction control module outputs a third enable signal EN, which is used to control whether the second conduction moment control unit, the second feedback adjustment unit and the second conduction duration control unit are working; the third enable signal EN will only be logic 1 when the number of conduction valleys in the previous switching cycle of the system is less than NMAX (preferably, this patent considers NMAX=6, because the valley number range for valley locking of the primary side switch controller is usually 1 to 6) and is in the free resonance stage, that is, the compensation conduction control module will work at this time.

[0403] The drain voltage signal VDS_SNS of the freewheeling switch tube is a key signal for compensation conduction control. The second conduction moment control unit, the second feedback adjustment unit and the second conduction duration control unit generate a freewheeling switch tube conduction control signal DRVCMP based on the drain voltage signal VDS_SNS information of the freewheeling switch tube, the third enable signal EN and the freewheeling conduction logic control signal DRVM. This signal is used to control the freewheeling switch tube to be turned on again during the resonance period to achieve zero voltage conduction of the primary side switch tube.

[0404] It can be understood that the second conduction moment control unit, the second feedback adjustment unit and the second conduction duration control unit can realize the compensation conduction mode and feedback adjustment mode in the above-mentioned switching power supply control method when the target switch tube is a freewheeling switch tube.

[0405] like Figure 13 As shown, the specific structure and control logic of the second conduction moment control unit, the second feedback adjustment unit and the second conduction duration control unit are basically the same as those of the first conduction moment control unit, the first feedback adjustment unit and the first conduction duration control unit in the above embodiment. The main difference is that the drain terminal voltage signal of the primary side switch tube in the first conduction moment control unit, the first feedback adjustment unit and the first conduction duration control unit in the above embodiment is replaced by the drain terminal voltage signal of the freewheeling switch tube, and the input end of the second conduction moment control unit in this embodiment does not receive the conduction valley number Nvalley of the primary side switch tube (the primary and secondary sides do not communicate, the specific reason has been explained in the above switching power supply method and will not be repeated here). The rest of the control logic will not be repeated.

[0406] According to the control system of the switching power supply provided in the embodiment of the present application, by providing a freewheeling conduction control module, a second conduction moment control unit, a second feedback adjustment unit, a second conduction duration control unit, a second logical or operator, and a secondary side switch controller of the driving circuit, it is possible to achieve, when the target switch tube is a freewheeling switch tube, on the basis of the secondary side switch controller controlling the on-off state of the freewheeling switch tube to achieve freewheeling conduction control of the switching power supply, by multiplexing the freewheeling switch tube to achieve, when the target switch tube is a freewheeling switch tube, the determination of the target moment and target duration corresponding to the compensation conduction mode and the feedback adjustment mode, and based on the determined target moment and target duration, the control of the on-off state of the freewheeling switch tube in different working modes to achieve the functional effects corresponding to each working mode, improve the compatibility and adaptability of zero voltage conduction control; and there is no need to design a complex controller, saving design costs.

[0407] In some embodiments, the second conduction timing control unit may include:

[0408] a second valley detection circuit, wherein the input end of the second valley detection circuit is used to receive the drain terminal voltage signal of the freewheeling switch tube, and the output end of the second valley detection circuit is used to output a fifth pulse signal; the fifth pulse signal includes a short-term high-level signal used to represent the resonance valley of the drain terminal voltage signal of the freewheeling switch tube during the free resonance process;

[0409] a third logical OR operator, wherein a thirty-third input terminal of the third logical OR operator is connected to the output terminal of the second valley detection circuit, and a thirty-fourth input terminal of the third logical OR operator is used to receive a second control signal; the second control signal is a pulse signal generated after a rising edge delay of the second square wave signal, and is used to determine, when the operating mode of the current switching cycle is the feedback regulation mode, a second resonance valley of the drain terminal voltage signal of the freewheeling switch tube during the free resonance process as the target valley;

[0410] a fifth rising edge pulse generator, wherein the input end of the fifth rising edge pulse generator is used to receive a freewheeling conduction logic control signal;

[0411] a third counter, wherein the input end of the third counter is respectively connected to the output end of the third logic OR operator and the fifth rising edge pulse generator; the output end of the third counter is used to output the valley count value of the resonance valley of the drain terminal voltage signal of the freewheeling switch tube during the free resonance process; and in the current switching cycle, when the freewheeling conduction logic control signal has a rising edge, the valley top count value is cleared;

[0412] A valley bottom number counting circuit is turned on, wherein the input end of the valley bottom number counting circuit is used to receive a drain terminal voltage signal of the freewheeling switch tube;

[0413] a second digital comparator, wherein a thirty-fifth input terminal of the second digital comparator is connected to the output terminal of the third counter, and a thirty-sixth input terminal of the second digital comparator is connected to the output terminal of the conduction valley bottom counting circuit; the output terminal of the second digital comparator is used to output a fourth comparison signal; the fourth comparison signal is used to determine whether the drain terminal voltage signal of the freewheeling switch tube reaches the target valley bottom in the current switching cycle;

[0414] a sixth rising edge pulse generator, wherein an input end of the sixth rising edge pulse generator is connected to an output end of the second digital comparator;

[0415] The first logic AND operator, the thirty-seventh input terminal of the first logic AND operator is connected to the output terminal of the sixth rising edge pulse generator, and the thirty-eighth input terminal is used to receive a third enable signal; the output terminal of the first logic AND operator is used to output a third conduction control signal; the third enable signal is used to control whether the second conduction moment control unit, the second feedback adjustment unit and the second conduction duration control unit are working; the rising edge moment of the third conduction control signal is used to represent the target moment.

[0416] In this embodiment, if Figure 14 As shown, it can be understood that the specific structure and control logic of this embodiment are basically the same as those of the first conduction time control unit in the above embodiment. The main difference is that the drain terminal voltage signal of the primary side switch tube in the first conduction time control unit in the above embodiment is replaced by the drain terminal voltage signal of the freewheeling switch tube; and in this embodiment, the control signal for controlling the valley top count value of the third counter to be cleared is a pulse signal generated by the freewheeling conduction logic control signal after passing through the fifth rising edge pulse generator; and in this embodiment, as Figure 14 As shown, the conduction valley number of the primary side switch tube needs to be obtained based on the drain voltage signal of the freewheeling switch tube through the conduction valley number statistics circuit; the rest of the control logic is not described in detail.

[0417] According to the control system of the switching power supply provided in the embodiment of the present application, by providing a second valley detection circuit, a third logic OR operator, a fifth rising edge pulse generator, a third counter, a conduction valley bottom number statistics circuit, a second digital comparator, a sixth rising edge pulse generator and a second conduction time control unit of the first logic AND operator, it is possible to determine the corresponding different target moments when each switching cycle is in the compensation conduction mode or the feedback regulation mode based on the target valley, the second control signal, the freewheeling conduction logic control signal and the resonant valley of the drain terminal voltage of the freewheeling switch tube obtained by real-time counting, thereby improving the reliability of the control system.

[0418] In some embodiments, the second feedback adjustment unit may include:

[0419] a fourth counter, wherein an input end of the fourth counter is used to receive an inverted signal of the pulse signal of the freewheeling conduction logic control signal;

[0420] a fifth logical AND operator, wherein the input end of the fifth logical AND operator is connected to the output end of the fourth counter, and the output end of the fifth logical AND operator is used to output the first square wave signal;

[0421] The second rising edge delayed pulse generator has an input end connected to the output end of the fifth logic AND operator; and an output end of the second rising edge delayed pulse generator is used to output a second control signal.

[0422] In this embodiment, if Figure 15 As shown, in the actual implementation process, the specific structure and control logic for obtaining the second control signal in this embodiment are basically the same as the structure and control logic for obtaining the first control signal by the first feedback regulation unit in the above embodiment. The difference is that the inverted signal of the gate drive voltage logic control signal of the primary side switch tube in the first feedback regulation unit in the above embodiment is replaced by the inverted signal of the pulse signal of the freewheeling conduction logic control signal; the rest of the control logic is not repeated.

[0423] According to the control system of the switching power supply provided in the embodiment of the present application, by providing a second feedback adjustment unit with a fourth counter, a fifth logic AND operator and a second rising edge delay pulse generator, it is possible to effectively obtain the second control signal for generating the target moment, thereby improving the reliability of the control system.

[0424] In some embodiments, the second feedback adjustment unit may further include:

[0425] A platform voltage sampling circuit, wherein the input end of the platform voltage sampling circuit is used to receive the drain voltage signal of the freewheeling switch tube; the output end of the platform voltage sampling circuit is used to output the platform voltage of the drain voltage of the freewheeling switch tube;

[0426] a third subtraction circuit, wherein the thirty-ninth input terminal of the third subtraction circuit is connected to the output terminal of the platform voltage sampling circuit, and the fortieth input terminal receives a fifth threshold voltage; the fifth threshold voltage is used to subtract the platform voltage of the drain terminal voltage of the freewheeling switch tube to generate a first threshold voltage; and the output terminal of the third subtraction circuit is used to output the first threshold voltage;

[0427] A fourth subtraction circuit, wherein the forty-first input terminal of the fourth subtraction circuit is connected to the output terminal of the third subtraction circuit, and the forty-second input terminal is used to receive a sixth threshold voltage; the sixth threshold voltage is used to subtract the platform voltage of the drain terminal voltage of the freewheeling switch tube to generate a second threshold voltage; the output terminal of the fourth subtraction circuit is used to output the second threshold voltage.

[0428] In this embodiment, it can be understood that when the target switch tube is a freewheeling switch tube, the platform voltage of the drain terminal voltage of the freewheeling switch tube can be sampled based on the drain terminal voltage signal of the freewheeling switch tube, and then the first threshold voltage and the second threshold voltage can be determined based on the difference between the platform voltage and the fifth threshold voltage and the fifth threshold voltage and the sixth threshold voltage, wherein the values of the fifth threshold voltage and the sixth threshold voltage can be customized by the user. In the actual execution process, by adjusting the fifth threshold voltage and the sixth threshold voltage, the effect of adjusting the first threshold voltage and the second threshold voltage can be achieved.

[0429] like Figure 15 As shown, in the actual implementation process, the drain voltage signal VDS_SNS of the freewheeling switch tube is connected to the input end of the platform voltage sampling circuit, and the platform voltage sampling circuit samples the platform value Vdpk of VDS_SNS, that is, the sampling value of the platform voltage of the drain voltage VD_S of the freewheeling switch tube.

[0430] The non-inverting input terminal INA of the subtractor 1 (the third subtractor) is connected to the plateau value Vdpk, and the inverting input terminal INB is connected to the fifth threshold voltage VA. After subtraction operation, the first threshold voltage VTH_H is generated, where VTH_H=Vdpk-VA.

[0431] Subtractor 2 (the fourth subtractor) has its non-inverting input terminal INA connected to VTH_H and its inverting input terminal INB connected to the sixth threshold voltage VB. After subtraction, a second threshold voltage VTH_L is generated, where VTH_L = VTH_H - VB. Adjusting the fifth and sixth threshold voltages VA and VB adjusts the first and second threshold voltages VTH_H and VTH_L.

[0432] According to the control system of the switching power supply provided in the embodiment of the present application, by providing a second feedback adjustment unit including a platform voltage sampling circuit, a third subtraction circuit, and a fourth subtraction circuit, it is possible to achieve, when the target switching tube is a freewheeling switching tube, the control logic of the first threshold voltage and the second threshold voltage based on the platform voltage of the drain terminal voltage of the freewheeling switching tube obtained by sampling, thereby improving the reliability of the control system.

[0433] In some embodiments, the second feedback adjustment unit may further include:

[0434] a fourth comparator, wherein the forty-third input terminal of the fourth comparator is used to receive the second threshold voltage, and the forty-fourth input terminal of the fourth comparator is used to receive the drain voltage signal of the freewheeling switch tube; the output terminal of the fourth comparator is used to output a fifth logic signal, and the high level time of the fifth logic signal indicates that the drain voltage signal is less than the second threshold voltage;

[0435] a fifth comparator, wherein the forty-fifth input terminal of the fifth comparator is used to receive the drain terminal voltage signal of the freewheeling switch tube, and the forty-sixth input terminal of the fifth comparator is used to receive the first threshold voltage; the output terminal of the fifth comparator is used to output a sixth logic signal, and the high level time of the sixth logic signal indicates that the drain terminal voltage signal is greater than the first threshold voltage;

[0436] a second valley detection circuit, wherein the input end of the second valley detection circuit is used to receive the drain terminal voltage signal of the freewheeling switch tube, and the output end of the second valley detection circuit is used to output a sixth pulse signal, wherein the short-term high-level signal included in the sixth pulse signal is used to represent the resonance valley of the drain terminal voltage signal of the freewheeling switch tube during the free resonance process;

[0437] a sixth logical AND operator, wherein a forty-seventh input terminal of the sixth logical AND operator is connected to the output terminal of the fourth comparator, a forty-eighth input terminal is used to receive the second square wave signal, a forty-ninth input terminal is used to receive the fourth comparison signal, and a fiftieth input terminal is connected to the output terminal of the second valley detection circuit; the output terminal of the sixth logical AND operator is used to output a fifth comparison signal, and the high-level time of the fifth comparison signal indicates that the target drain terminal voltage is less than the second threshold voltage;

[0438] a seventh logical AND operator, wherein a fifty-first input terminal of the seventh logical AND operator is connected to the output terminal of the fifth comparator, a fifty-second input terminal is used to receive the second square wave signal, a fifty-third input terminal is used to receive the fourth comparison signal, and a fifty-fourth input terminal is connected to the output terminal of the second valley detection circuit; the output terminal of the seventh logical AND operator is used to output a sixth comparison signal, and the high-level time of the sixth comparison signal indicates that the target drain terminal voltage is greater than the first threshold voltage;

[0439] a second bidirectional counter, wherein the fifty-fifth input terminal of the second bidirectional counter is connected to the output terminal of the sixth logical AND operator, and the fifty-sixth input terminal of the second bidirectional counter is connected to the output terminal of the seventh logical AND operator; the output terminal of the second bidirectional counter is used to output a second count value, and an increase or decrease in the second count value represents an increase or decrease in the target duration;

[0440] a second DAC circuit, wherein an input end of the second DAC circuit is connected to an output end of the second bidirectional counter;

[0441] The fourth limiting circuit has an input end connected to the output end of the second DAC circuit, and an output end of the fourth limiting circuit is used to output a fourth conduction control signal, wherein the high level duration of the fourth conduction control signal represents the target duration.

[0442] In this embodiment, it can be understood that the specific structure and control logic of this embodiment are basically the same as the structure for obtaining the second conduction control signal in the first feedback regulation unit in the above embodiment. The main difference is that the drain terminal voltage signal of the primary switch tube in the first feedback regulation unit in the above embodiment is replaced by the drain terminal voltage signal of the freewheeling switch tube; and in this embodiment, Figure 15 As shown, when the drain terminal voltage signal VDS_SNS of the freewheeling switch tube is less than the second threshold voltage VTH_L, the second count value T_Cnt of the second bidirectional counter is increased by 1; when the drain terminal voltage signal VDS_SNS of the freewheeling switch tube is greater than the first threshold voltage VTH_H, the second count value T_Cnt of the second bidirectional counter is decreased by 1; the rest of the control logic is not described in detail.

[0443] According to the control system of the switching power supply provided in the embodiment of the present application, by providing a second feedback adjustment unit including a fourth comparator, a fifth comparator, a second valley detection circuit, a sixth logic AND operator, a seventh logic AND operator, a second bidirectional counter, a second DAC circuit and a fourth limiting circuit, it is possible to implement, when the target switching tube is a freewheeling switching tube, the control logic for adjusting the target duration corresponding to the next switching cycle based on the relationship between the target drain voltage and the first threshold voltage and the second threshold voltage, thereby improving the reliability of the control system.

[0444] In some embodiments, the second feedback adjustment unit may include:

[0445] a second timing circuit, the second timing circuit being used to generate a second square wave signal;

[0446] a second resonant period conduction control unit, wherein the input end of the second resonant period conduction control unit is connected to the output end of the second timing circuit, and is used to determine the second resonant valley bottom of the drain terminal voltage signal of the freewheeling switch tube during the free resonance process as the target valley bottom;

[0447] a third sampling and holding circuit, wherein the input terminal of the third sampling and holding circuit is connected to the output terminal of the second resonance period conduction control unit; a fifth output terminal of the third sampling and holding circuit is used to output a seventh logic signal, and when the third sampling and holding circuit completes sampling the drain terminal voltage of the second resonance valley, the seventh logic signal is set to a high level; and a sixth output terminal of the third sampling and holding circuit is used to output the drain terminal voltage of the second resonance valley;

[0448] a seventh rising edge pulse generator, wherein the input end of the seventh rising edge pulse generator is connected to the fifth output end, and the output end of the seventh rising edge pulse generator is used to output a seventh pulse signal, wherein the seventh pulse signal is a pulse signal having a rising edge identical to that of the seventh logic signal;

[0449] a fifth subtraction circuit, wherein a fifty-seventh input terminal of the fifth subtraction circuit is connected to the sixth output terminal, a fifty-eighth input terminal is used to receive the third threshold voltage, and an output terminal of the fifth subtraction circuit is used to output a third error signal, the third error signal being used to represent a difference between the drain terminal voltage at the second resonance valley and the third threshold voltage;

[0450] a fourth switch, one end of the fourth switch being connected to the output end of the fifth subtraction circuit, and the seventh pulse signal controlling an on / off state of the fourth switch;

[0451] a third PI controller, wherein an input end of the third PI controller is connected to the other end of the fourth switch;

[0452] A fifth amplitude limiting circuit, wherein the input end of the fifth amplitude limiting circuit is connected to the output end of the third PI controller, and the output end of the fifth amplitude limiting circuit is used to output a fourth conduction control signal.

[0453] In this embodiment, it can be understood that the structure and control logic of this embodiment are similar to those of the first feedback regulation unit based on PI control for obtaining the second conduction control signal. The main difference is that after the timing of the second timing circuit is reached, if the number of valleys of the freewheeling switch tube (the number of valleys of the target valley) is Nvalley in the current switching cycle in the compensation conduction mode, then when the target switch tube is the freewheeling switch tube and the current switching cycle is in the feedback regulation mode, the second resonant cycle conduction control unit controls the freewheeling switch tube to be turned on at the Nvalley-1th valley; the remaining control logic is not described in detail. According to the control system of the switching power supply provided by the embodiment of the present application, by providing the second feedback regulation unit with the second timing circuit, the second resonant cycle conduction control unit, the third sample and hold circuit, the seventh rising edge pulse generator, the fifth subtraction circuit, the fourth switch, the third PI controller and the fifth limiter circuit, it is possible to implement PI control based on the difference between the target drain voltage and the third threshold voltage when the target switch tube is the freewheeling switch tube, so as to adjust the control logic for obtaining the target duration corresponding to the next switching cycle, thereby improving the reliability of the control system.

[0454] In some embodiments, the second on-time length control unit may have a structure and control logic similar to those of the first on-time length control unit, and this application will not elaborate on them here.

[0455] In some embodiments, as Figure 20 As shown, an embodiment of the present application further provides an electronic device 2000, including a processor 2001, a memory 2002, and a computer program stored in the memory 2002 and executable on the processor 2001. When the program is executed by the processor 2001, the various processes of the above-mentioned switching power supply control method embodiment are implemented, and the same technical effect can be achieved. To avoid repetition, it will not be described here.

[0456] It should be noted that the electronic devices in the embodiments of the present application include mobile electronic devices and non-mobile electronic devices.

[0457] An embodiment of the present application further provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the various processes of the above-mentioned switching power supply control method embodiment are implemented, and the same technical effects can be achieved. To avoid repetition, they are not described here.

[0458] The processor is the processor in the electronic device described in the above embodiment. The readable storage medium includes a computer readable storage medium, such as a computer read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0459] An embodiment of the present application further provides a computer program product, including a computer program, which implements the above-mentioned control method of the switching power supply when executed by a processor.

[0460] The processor is the processor in the electronic device described in the above embodiment. The readable storage medium includes a computer readable storage medium, such as a computer read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0461] An embodiment of the present application further provides a chip, which includes a processor and a communication interface, wherein the communication interface is coupled to the processor, and the processor is used to run programs or instructions to implement the various processes of the above-mentioned switching power supply control method embodiment, and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0462] It should be understood that the chip mentioned in the embodiments of the present application can also be called a system-level chip, a system chip, a chip system or a system-on-chip chip, etc.

[0463] It should be noted that, in this article, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or the process comprising a series of elements not only includes those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element. In addition, it should be pointed out that the scope of the methods and devices in the embodiments of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in the opposite order according to the functions involved. For example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0464] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus the necessary general hardware platform, and of course can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present application, or the part that contributes to the relevant technology, can be embodied in the form of a computer software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes a number of instructions for enabling a terminal (which can be a mobile phone, computer, server, or network device, etc.) to execute the methods described in each embodiment of the present application.

[0465] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of this application, ordinary technicians in this field can also make many forms without departing from the purpose of this application and the scope of protection of the claims, all of which are within the protection of this application.

[0466] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" 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 illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0467] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and intent of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A method for controlling a switching power supply, characterized in that: The switching power supply includes a transformer, a primary switch connected to the primary side of the transformer, and a freewheeling switch connected to the secondary side of the transformer; the method includes: In the feedback regulation mode, after controlling the target switch tube to be turned on for a target period of time and then turned off at a target time, a target drain terminal voltage is obtained; the target drain terminal voltage is the voltage at the first resonance valley bottom that appears after the drain terminal voltage of the primary side switch tube recovers to a free resonance state after the target switch tube is turned off, or the voltage at the first resonance valley top that appears after the drain terminal voltage of the freewheeling switch tube recovers to a free resonance state; the target switch tube is the freewheeling switch tube or a compensation switch tube connected between the primary side switch tube and ground; the target time and the target drain terminal voltage are determined based on the target switch tube; Based on the target drain voltage and the target voltage range, the target duration corresponding to the next turn-on of the target switch tube is determined until the target drain voltage is within the target voltage range; when the target switch tube is the compensation switch tube, the target voltage range is a voltage within a first preset range close to 0; when the target switch tube is the freewheeling switch tube, the target voltage range is a voltage within a second preset range close to the platform voltage of the freewheeling switch tube.

2. The control method of the switching power supply according to claim 1, characterized in that: The target voltage range includes a first threshold voltage and a second threshold voltage, the second threshold voltage being smaller than the first threshold voltage; The determining, based on the target drain voltage and the target voltage range, a target duration corresponding to turning on the target switch tube next time, includes: When the target drain voltage is less than the first threshold voltage and greater than the second threshold voltage, controlling the target duration corresponding to the next turn-on of the target switch tube to remain unchanged; When the target drain voltage is not less than the first threshold voltage and greater than the second threshold voltage, the target duration corresponding to the next turn-on of the target switch tube is adjusted based on the target switch tube and based on the relationship between the target drain voltage and the first threshold voltage and the second threshold voltage.

3. The control method of the switching power supply according to claim 2, characterized in that: The adjusting, based on the target switch tube and based on the magnitude relationship between the target drain terminal voltage and the first threshold voltage and the second threshold voltage, the target duration corresponding to the next turn-on of the target switch tube includes: When the target switch is the compensation switch and the target drain voltage is greater than or equal to the first threshold voltage, increasing the target time based on a target step size; When the target switch is the compensation switch and the target drain voltage is less than or equal to the second threshold voltage, reducing the target duration based on the target step size; When the target switch is the freewheeling switch and the target drain voltage is greater than or equal to the first threshold voltage, reducing the target duration based on a target step size; When the target switch tube is the freewheeling switch tube and the target drain terminal voltage is less than or equal to the second threshold voltage, the target time length is increased based on the target step length.

4. The control method of the switching power supply according to claim 1, wherein: The target voltage range includes a third threshold voltage; and determining a target duration corresponding to turning on the target switch next time based on the target drain voltage and the target voltage range includes: The difference between the target drain terminal voltage and the third threshold voltage is subjected to PI control to adjust the target duration corresponding to the next turn-on of the target switch tube.

5. The method for controlling a switching power supply according to any one of claims 1 to 4, wherein: When the target switch is the compensation switch, the target voltage range is a voltage within a first preset range close to 0. In a case where the target switch tube is the freewheeling switch tube, the target voltage range is a voltage within a second preset range close to the platform voltage of the freewheeling switch tube, including: When the target switch is the compensation switch, the first voltage is determined as a first threshold voltage in the target voltage range, and the second voltage is determined as a second threshold voltage in the target voltage range; the first voltage is greater than the second voltage; and the second voltage is a voltage whose difference from zero voltage is less than a first preset threshold, or is an equivalent conversion voltage of the drain voltage of the primary switch. When the target switch is the freewheeling switch, the third voltage is determined as a first threshold voltage in the target voltage range, and the fourth voltage is determined as a second threshold voltage in the target voltage range; the fourth voltage is greater than the third voltage; the fourth voltage is a voltage whose difference from the platform voltage of the freewheeling switch is less than a second preset threshold, or is an equivalent conversion voltage of the platform voltage of the drain terminal voltage of the freewheeling switch; When the target switch is the compensation switch, the fifth voltage is determined to be a third threshold voltage in the target voltage range, where the difference between the fifth voltage and zero voltage is less than a third preset threshold. When the target switch tube is the freewheeling switch tube, the sixth voltage is determined as the third threshold voltage in the target voltage range, and the sixth voltage is a voltage whose difference with the platform voltage of the freewheeling switch tube is less than a fourth preset threshold.

6. The method for controlling a switching power supply according to any one of claims 1 to 4, wherein: The target time and the target drain voltage are determined based on the target switch tube, including: When the target switch is the compensation switch, the target time is determined as the time at which the drain voltage of the primary switch is at a target valley top during free resonance, and the target drain voltage is determined as the drain voltage at the first resonance valley bottom that appears after the drain voltage of the primary switch recovers to free resonance after the compensation switch is turned off. When the target switch tube is the freewheeling switch tube, the target moment is determined as the moment when the drain terminal voltage of the freewheeling switch tube is at the target valley bottom during the free resonance process, and the target drain terminal voltage is determined as the drain terminal voltage at the first resonance valley top that appears after the freewheeling switch tube is turned off and the drain terminal voltage of the freewheeling switch tube recovers to the free resonance.

7. The method for controlling a switching power supply according to any one of claims 1 to 4, wherein: The target voltage range includes a third threshold voltage, and the third threshold voltage is determined based on the following steps: With the final zero-voltage turn-on effect as the goal, when the target switch tube is the compensation switch tube, the third threshold voltage is determined by adjusting the relative distance of the third threshold voltage compared to the zero voltage; when the target switch tube is the freewheeling switch tube, the third threshold voltage is determined by adjusting the relative distance of the third threshold voltage compared to the platform voltage of the freewheeling switch tube.

8. The method for controlling a switching power supply according to any one of claims 1 to 4, wherein: Also includes: After determining a target duration corresponding to the next turn-on of the target switch tube based on the target drain voltage and the target voltage range, exiting the feedback regulation mode and timing the next feedback regulation mode intervention, so that the target drain voltage is within the target voltage range after multiple feedback intervention adjustments; After determining the target duration corresponding to the next turn-on of the target switch tube based on the target drain voltage and the target voltage range, returning to execute the method of controlling the target switch tube to be turned on for the target duration and turned off at the target time, obtaining the target drain voltage until the target drain voltage is within the target voltage range, exiting the feedback regulation mode and starting the interval timing for the next feedback regulation mode intervention.

9. A control system for a switching power supply, characterized in that: include: transformer; A primary switching tube connected to the primary side of the transformer; A freewheeling switch connected to the secondary side of the transformer; a primary switch controller connected to the primary switch tube and configured to control the on / off state of the primary switch tube based on a drain terminal voltage signal of the primary switch tube; A secondary side switch controller, connected to the freewheeling switch tube, for freewheeling conduction control of the switching power supply; The secondary side switch controller is further configured to control the on / off state of the freewheeling switch based on the target time and the target duration; and is further configured to, in the compensation conduction mode, determine the target duration as the target duration corresponding to the next turn-on of the freewheeling switch; In the feedback regulation mode, the target duration is adjusted based on the target drain voltage and the target voltage range, and the adjusted target duration is determined as the target duration corresponding to the next time the freewheeling switch is turned on; In the case where a compensation switch tube is connected between the primary switch tube and the ground, the primary switch controller is further configured to control the on / off state of the compensation switch tube based on the target time and the target duration; and is further configured to, in a compensation conduction mode, determine the target duration as the target duration corresponding to the next turn-on of the compensation switch tube; In the feedback regulation mode, the target duration is adjusted based on the target drain voltage and the target voltage range, and the adjusted target duration is determined as the target duration corresponding to the next time the compensation switch is turned on.

10. The control system of the switching power supply according to claim 9, characterized in that: The primary side switch controller comprises: A main power tube conduction control module, the main power tube conduction control module is used to control the on / off state of the primary side switch tube based on the drain terminal voltage of the primary side switch tube; a first conduction timing control unit, wherein an input end of the first conduction timing control unit is connected to an output end of the main power tube conduction control module, and another input end of the first conduction timing control unit is used to receive a drain terminal voltage signal of the primary side switch tube for determining the target time; a first feedback regulation unit, wherein an input end of the first feedback regulation unit is respectively connected to an output end of the main power tube conduction control module and an output end of the first conduction timing control unit; another input end of the first feedback regulation unit is used to receive a drain terminal voltage signal of the primary side switch tube, so as to determine a target duration corresponding to the next conduction of the target switch tube; and an output end of the first feedback regulation unit is connected to an input end of the first conduction timing control unit; A first on-time control unit, wherein the input end of the first on-time control unit is respectively connected to the output end of the first on-time control unit and the output end of the first feedback adjustment unit, and is used to control the on-off state of the compensation switch tube based on the target time and the target duration corresponding to the current switching cycle.

11. The control system of the switching power supply according to claim 10, characterized in that: The first conduction timing control unit includes: a first valley detection circuit, wherein the input end of the first valley detection circuit is used to receive the drain-end voltage signal of the primary-side switching tube, and the output end of the first valley detection circuit is used to output a first pulse signal; the short-term high-level signal included in the first pulse signal is used to represent the resonance valley of the drain-end voltage signal of the primary-side switching tube during the free resonance process; a first logical OR operator, wherein a first input terminal of the first logical OR operator is connected to the output terminal of the first valley detection circuit, and a second input terminal is used to receive a first control signal; the first control signal is a pulse signal generated after a rising edge delay of the first square wave signal; the first square wave signal is generated based on an inverted signal of a logic control signal of a gate drive voltage of the primary-side switch tube, and is used to determine the target time; a first counter, wherein the third input terminal of the first counter is connected to the output terminal of the first logical OR operator, and the fourth input terminal is used to receive the gate drive voltage logic control signal of the primary switch tube; the output terminal of the first counter is used to output a valley top count value of the resonance valley top of the drain terminal voltage signal of the primary switch tube during the free resonance process; and in the current switching cycle, when a rising edge occurs in the gate drive voltage logic control signal of the primary switch tube, the valley top count value is cleared; a first digital comparator, wherein a fifth input terminal of the first digital comparator is connected to the output terminal of the first counter, and a sixth input terminal is used to receive the target valley signal; the target valley signal is used to indicate the number of valleys at the target moment; the output terminal of the first digital comparator is used to output a first comparison signal; the first comparison signal is used to determine whether the drain terminal voltage signal of the primary switching tube reaches the target valley within the current switching cycle; a first rising edge pulse generator, wherein an input end of the first rising edge pulse generator is connected to an output end of the first digital comparator; A first logic AND operator, wherein the seventh input terminal of the first logic AND operator is connected to the output terminal of the first rising edge pulse generator, and the eighth input terminal is used to receive a first enable signal; the output terminal of the first logic AND operator is used to output a first conduction control signal; the first enable signal is used to control whether the first conduction moment control unit, the first feedback adjustment unit and the first conduction duration control unit are working; the rising edge moment of the first conduction control signal is used to represent the target moment.

12. The control system of the switching power supply according to claim 10, characterized in that: The first feedback adjustment unit includes: A second counter, wherein an input end of the second counter is used to receive an inverted signal of a gate drive voltage logic control signal of the primary side switch tube; a second logic AND operator, wherein an input end of the second logic AND operator is connected to an output end of the second counter, and an output end of the second logic AND operator is used to output a first square wave signal; A first rising edge delayed pulse generator, wherein the input end of the first rising edge delayed pulse generator is connected to the output end of the second logic AND operator; the output end of the first rising edge delayed pulse generator is used to output a first control signal.

13. The control system of the switching power supply according to claim 10, characterized in that: The first feedback adjustment unit further includes: a first comparator, wherein a ninth input terminal of the first comparator is used to receive the drain voltage signal of the primary-side switch tube, and a tenth input terminal of the first comparator is used to receive a first threshold voltage; an output terminal of the first comparator is used to output a first logic signal, and a high-level time of the first logic signal indicates that the drain voltage signal is greater than the first threshold voltage; a second comparator, wherein the eleventh input terminal of the second comparator is used to receive the second threshold voltage, and the twelfth input terminal of the second comparator is used to receive the drain voltage signal of the primary switch tube; the output terminal of the second comparator is used to output a second logic signal, and the high level time of the first logic signal indicates that the drain voltage signal is less than the second threshold voltage; a first valley detection circuit, wherein the input end of the first valley detection circuit is used to receive the drain terminal voltage signal of the primary side switch tube, and the output end of the first valley detection circuit is used to output a fourth pulse signal, wherein the short-term high-level signal included in the fourth pulse signal is used to represent the resonance valley of the drain terminal voltage signal of the primary side switch tube during the free resonance process; a third logical AND operator, wherein a thirteenth input terminal of the third logical AND operator is connected to the output terminal of the first comparator, a fourteenth input terminal is used to receive the first square wave signal, a fifteenth input terminal is used to receive the first comparison signal, and a sixteenth input terminal is connected to the output terminal of the first valley detection circuit; the output terminal of the third logical AND operator is used to output a second comparison signal, and the high-level time of the second comparison signal indicates that the target drain terminal voltage is greater than the first threshold voltage; a fourth logical AND operator, wherein a seventeenth input terminal of the fourth logical AND operator is connected to the output terminal of the second comparator, an eighteenth input terminal is used to receive the first square wave signal, a nineteenth input terminal is used to receive the first comparison signal, and a twentieth input terminal is connected to the output terminal of the first valley detection circuit; the output terminal of the fourth logical AND operator is used to output a third comparison signal, and the high-level time of the third comparison signal indicates that the target drain terminal voltage is less than the second threshold voltage; a first bidirectional counter, wherein a twenty-first input terminal of the first bidirectional counter is connected to the output terminal of the third logical AND operator, and a twenty-second input terminal of the first bidirectional counter is connected to the output terminal of the fourth logical AND operator; the output terminal of the first bidirectional counter is used to output a first count value, and an increase or decrease in the first count value represents an increase or decrease in the target duration; a first DAC circuit, wherein an input terminal of the first DAC circuit is connected to an output terminal of the first bidirectional counter; A first limiting circuit, wherein the input end of the first limiting circuit is connected to the output end of the first DAC circuit, the output end of the first limiting circuit is used to output a second conduction control signal, and the high level duration of the second conduction control signal represents the target duration.

14. The control system of the switching power supply according to claim 10, characterized in that: The first feedback adjustment unit includes: a first timing circuit, configured to generate a first square wave signal; a first resonant period conduction control unit, wherein an input end of the first resonant period conduction control unit is connected to an output end of the first timing circuit, and is used to determine a target valley top at the target time; a first sampling and holding circuit, wherein an input terminal of the first sampling and holding circuit is connected to an output terminal of the first resonant period conduction control unit; a first output terminal of the first sampling and holding circuit is used to output a third logic signal, and when the first sampling and holding circuit completes sampling the target drain terminal voltage, the third logic signal is set to a high level; and a second output terminal of the first sampling and holding circuit is used to output the target drain terminal voltage; a third rising edge pulse generator, wherein the input end of the third rising edge pulse generator is connected to the first output end, and the output end of the third rising edge pulse generator is used to output a second pulse signal, wherein the second pulse signal is a pulse signal having the same rising edge as the third logic signal; a first subtraction circuit, wherein a twenty-third input terminal of the first subtraction circuit is connected to the second output terminal, a twenty-fourth input terminal of the first subtraction circuit is used to receive a third threshold voltage, and an output terminal of the first subtraction circuit is used to output a first error signal, wherein the first error signal is used to represent a difference between the target drain terminal voltage and the third threshold voltage; a second switch, one end of the second switch being connected to the output end of the first subtraction circuit, and the second pulse signal controlling an on / off state of the second switch; a first PI controller, wherein an input end of the first PI controller is connected to the other end of the second switch; A second amplitude limiting circuit, wherein the input end of the second amplitude limiting circuit is connected to the output end of the first PI controller, and the output end of the second amplitude limiting circuit is used to output a second conduction control signal.

15. The control system of the switching power supply according to claim 10, characterized in that: The first feedback adjustment unit includes: a second sample-and-hold circuit, wherein the twenty-fifth input terminal of the second sample-and-hold circuit is used to receive the first enable signal, and the twenty-sixth input terminal of the second sample-and-hold circuit is used to receive the drain voltage signal of the primary-side switch tube; the third output terminal of the second sample-and-hold circuit is used to output a fourth logic signal, and when the second sample-and-hold circuit completes sampling the target drain voltage, the fourth logic signal is set to a high level; and the fourth output terminal of the second sample-and-hold circuit is used to output the target drain voltage; a fourth rising edge pulse generator, wherein the input end of the fourth rising edge pulse generator is connected to the third output end; the output end of the fourth rising edge pulse generator is used to output a third pulse signal, wherein the third pulse signal is a pulse signal having the same rising edge as the fourth logic signal; a second subtraction circuit, wherein a twenty-seventh input terminal of the second subtraction circuit is connected to the fourth output terminal, a twenty-eighth input terminal of the second subtraction circuit is used to receive a third threshold voltage, and an output terminal of the second subtraction circuit is used to output a second error signal, wherein the second error signal is used to represent a difference between the target drain terminal voltage and the third threshold voltage; a third switch, one end of the third switch being connected to the output end of the second subtraction circuit, and the third pulse signal controlling the on / off state of the third switch; a second PI controller, wherein an input end of the second PI controller is connected to the other end of the third switch; A third amplitude limiting circuit, wherein the input end of the third amplitude limiting circuit is connected to the output end of the second PI controller, and the output end of the third amplitude limiting circuit is used to output a second conduction control signal.

16. The control system of the switching power supply according to claim 10, characterized in that: The first on-time control unit includes: a current source, the current source being configured to output current; a first switch, connected in parallel with the current source, and controlled based on an inverted signal of a compensation switch conduction control signal, wherein the compensation switch conduction control signal is used to control an on / off state of the compensation switch; a first capacitor, the first capacitor being connected in parallel with the first switch; a third comparator, wherein a twenty-ninth input terminal of the third comparator is used to receive the voltage across the first capacitor, and a thirtieth input terminal of the third comparator is used to receive a second conduction control signal; a second rising edge pulse generator, wherein an input terminal of the second rising edge pulse generator is connected to an output terminal of the third comparator; A trigger, wherein the thirty-first input terminal of the trigger is used to receive the first conduction control signal, and the thirty-second input terminal is connected to the output terminal of the second rising edge pulse generator; the output terminal of the trigger is used to output the compensation switch tube conduction control signal.

17. The control system of the switching power supply according to claim 9, characterized in that: The secondary side switch controller includes: A freewheeling conduction control module, configured to control the freewheeling conduction of the switching power supply based on the drain terminal voltage of the freewheeling switch tube; a second conduction timing control unit, wherein an input end of the second conduction timing control unit is connected to the output end of the freewheeling conduction control module, and another input end of the second conduction timing control unit is used to receive a drain terminal voltage signal of the freewheeling switch tube for determining the target timing; a second feedback regulation unit, wherein the input end of the second feedback regulation unit is respectively connected to the output end of the freewheeling conduction control module and the output end of the second conduction timing control unit; another input end of the second feedback regulation unit is used to receive the drain terminal voltage signal of the freewheeling switch tube, so as to determine the target duration corresponding to the next conduction of the target switch tube; and the output end of the second feedback regulation unit is connected to the input end of the second conduction timing control unit; a second on-time control unit, wherein the input end of the second on-time control unit is connected to the output end of the second on-time control unit and the output end of the second feedback adjustment unit, respectively, and is used to control the on and off state of the freewheeling switch tube based on the target time and the target duration corresponding to the current switching cycle; a second logic OR operator, wherein the input end of the second logic OR operator is respectively connected to the output end of the freewheeling conduction control module and the output end of the second conduction duration control unit; A driving circuit, wherein the input end of the driving circuit is connected to the output end of the second logic OR operator, and the output end of the driving circuit is used to output the gate drive voltage signal of the freewheeling switch tube, which is used to control the freewheeling conduction of the freewheeling switch tube and control the on-off state of the freewheeling switch tube based on the target time and the target duration.

18. A chip, characterized in that: The chip includes a processor and a communication interface, the communication interface is coupled to the processor, and the processor is used to run a program or instruction to implement the control method of the switching power supply according to any one of claims 1 to 8.

Images