Control method and device of switching power supply system and switching power supply system

Abstract

The present application discloses a control method, device and switching power supply system for a switching power supply system, and belongs to the technical field of switching power supplies. The control method of the switching power supply system includes: obtaining the feedback voltage corresponding to the load of the switching power supply system in the current switching cycle, the input AC voltage of the switching power supply system and the driving voltage signal of the switching power supply system in the current switching cycle; based on the feedback voltage, the driving voltage signal and the input AC voltage, determining the reference voltage of the switching power supply system output by the frequency jitter circuit included in the switching power supply system in the next switching cycle; based on the reference voltage in the next switching cycle, adjusting the switching frequency of the switching power supply system in the next switching cycle. The control method of the switching power supply system of the present application reduces the electromagnetic interference of the switching power supply, and is suitable for the scenario where the switching frequency in the flyback switching power supply changes with the load, which broadens the applicable scenarios.

Description

Technical Field

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

[0002] With the continuous increase in the power of power adapters in recent years, the requirements for the integration and power density of flyback switching power supplies are also increasing. For flyback switching power supplies, increasing the switching frequency can reduce the size of the transformer and increase the power density, but increasing the switching frequency will increase switching losses and electromagnetic interference (EMI), so it is necessary to control the switching frequency jitter of the switching power supply. In the related art, there is a method of directly changing the switching frequency of the switching power supply to jitter the switching frequency, but for the flyback switching power supply in the quasi-resonant working mode, the switching frequency will change with the load. This method cannot be applied to the flyback switching power supply in the quasi-resonant working mode, and the applicable scenarios are limited, and the electromagnetic interference of the switching power supply cannot be effectively reduced. Summary of the invention

[0003] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes a control method, device and switching power supply system of a switching power supply system, which reduces the electromagnetic interference of the switching power supply and is suitable for the scenario where the switching frequency of a flyback switching power supply changes with the load, thus broadening the applicable scenarios.

[0004] In a first aspect, the present application provides a control method for a switching power supply system, comprising:

[0005] Acquire a feedback voltage corresponding to a load of the switching power system in a current switching cycle, an input AC voltage of the switching power system, and a driving voltage signal of the switching power system in the current switching cycle; the driving voltage signal changes correspondingly based on a conduction state of a power tube included in the switching power system;

[0006] Determine, based on the feedback voltage, the drive voltage signal and the input AC voltage, a reference voltage of the switching power supply system output by a frequency jitter circuit included in the switching power supply system in the next switching cycle;

[0007] Based on the reference voltage in the next switching cycle, the switching frequency of the switching power supply system in the next switching cycle is adjusted.

[0008] According to the control method of the switching power supply system provided in the embodiment of the present application, the working state of the components included in the frequency jittering circuit is adjusted by the feedback voltage, driving voltage signal and input AC voltage of the switching power supply system in the current switching cycle to change the voltage output by the frequency jittering circuit, and then determine the reference voltage in the next switching cycle, thereby changing the switching frequency in the next switching cycle to achieve switching frequency jittering, thereby reducing the electromagnetic interference of the switching power supply; and the switching frequency is dynamically adjusted according to the feedback voltage and other signals of the switching power supply system, which is suitable for the scenario where the switching frequency in the flyback switching power supply changes with the load, thereby broadening the applicable scenarios.

[0009] A control method for a switching power supply system according to an embodiment of the present application, wherein the reference voltage of the switching power supply system output by a frequency jitter circuit included in the switching power supply system in the next switching cycle is determined based on the feedback voltage and the drive voltage signal, comprising:

[0010] When it is determined that the switching power supply system is in a normal working state based on the feedback voltage, adjusting the operating parameters of the frequency jitter circuit included in the switching power supply system based on the feedback voltage, the drive voltage signal and the input AC voltage;

[0011] Based on the adjusted voltage output by the frequency jitter circuit, a reference voltage of the switching power supply system in the next switching cycle is determined.

[0012] A control method for a switching power supply system according to an embodiment of the present application, wherein the frequency jitter circuit comprises: a plurality of first resistors connected in series and a plurality of first switches for controlling the first resistors to be connected to the frequency jitter circuit, an operational amplifier, a first MOS tube, a second MOS tube and an output port, wherein the output port is used to output a reference voltage of the switching power supply system in the next switching cycle; one end of the second resistor is respectively connected to the inverting input end of the operational amplifier and the drain of the first MOS tube, and the output end of the operational amplifier is grounded via the second resistor, and the plurality of first resistors are grounded via a fourth resistor, one end of the first switch is connected to a side of the first resistor corresponding to the first switch close to the drain of the second MOS tube, the other end of the first switch is connected to the output port, the source of the first MOS tube is connected to the source of the second MOS tube, and the gate of the first MOS tube is respectively connected to the drain of the first MOS tube and the gate of the second MOS tube; the operating parameters of the frequency jitter circuit included in the switching power supply system are adjusted based on the feedback voltage, the drive voltage signal and the input AC voltage, including:

[0013] Inputting the feedback voltage to the non-inverting input terminal of the operational amplifier;

[0014] Based on the driving voltage signal, a target switch among the plurality of first switches is controlled to be closed, so as to control a first resistor corresponding to the target switch to be connected to the frequency jitter circuit.

[0015] In a control method for a switching power supply system according to an embodiment of the present application, the number of the plurality of switching cycles is m, the number of the plurality of first switches is n, wherein m and n are both positive integers; and the method of controlling a target switch among the plurality of first switches to close based on the driving voltage signal comprises:

[0016] When a falling edge of a driving voltage signal corresponding to a p-th switching cycle in the plurality of switching cycles is detected, controlling a-an+p-th first switch in the plurality of first switches to be closed, wherein p is a positive integer less than or equal to m, an-a+1≤p≤an+na≤m, and a is 0 or a positive even number;

[0017] When the falling edge of the driving voltage signal corresponding to the qth switching cycle in the multiple switching cycles is detected, the an+n-a+1-qth first switch in the multiple first switches is controlled to be closed, where q is a positive integer, an-a+1<q≤an+na-1≤m, and a is a positive odd number.

[0018] In a control method for a switching power supply system according to an embodiment of the present application, a third resistor is connected in series between the plurality of first resistors and the fourth resistor, and a second switch is connected in parallel to the third resistor; and adjusting the operating parameters of a frequency jitter circuit included in the switching power supply system based on the feedback voltage, the drive voltage signal and the input AC voltage comprises:

[0019] When the input AC voltage is greater than a target threshold, controlling the second switch to close;

[0020] When the input AC voltage is less than or equal to the target threshold, the second switch is controlled to be disconnected.

[0021] A control method for a switching power supply system according to an embodiment of the present application, wherein the reference voltage of the switching power supply system output by a frequency jitter circuit included in the switching power supply system in the next switching cycle is determined based on the feedback voltage, the drive voltage signal and the input AC voltage, comprising:

[0022] In the case where the switching power supply system is determined to be in an abnormal working state based on the feedback voltage, the frequency jitter circuit outputs the average of the upper limit value and the lower limit value of the first range, and determines the average value as the reference voltage of the switching power supply system in the next switching cycle; the first range is the variation range corresponding to the reference voltage determined based on the feedback voltage, the drive voltage signal and the input AC voltage when the switching power supply system is in a normal working state. In a second aspect, the present application provides a control device for a switching power supply system, comprising:

[0023] A first processing module, configured to obtain a feedback voltage corresponding to a load of the switching power supply system in a current switching cycle, an input AC voltage of the switching power supply system, and a driving voltage signal of the switching power supply system in the current switching cycle; the driving voltage signal changes correspondingly based on a conduction state of a power tube included in the switching power supply system;

[0024] A second processing module, configured to determine a reference voltage of the switching power supply system in a next switching cycle output by a frequency jitter circuit included in the switching power supply system based on the feedback voltage, the driving voltage signal and the input AC voltage;

[0025] The third processing module is used to adjust the switching frequency of the switching power supply system in the next switching cycle based on the reference voltage in the next switching cycle.

[0026] According to the control device of the switching power supply system provided in the embodiment of the present application, the working state of the components included in the frequency jittering circuit is adjusted by the feedback voltage, driving voltage signal and input AC voltage of the switching power supply system in the current switching cycle to change the voltage output by the frequency jittering circuit, and then determine the reference voltage in the next switching cycle, thereby changing the switching frequency in the next switching cycle to achieve switching frequency jittering, thereby reducing the electromagnetic interference of the switching power supply; and the switching frequency is dynamically adjusted according to signals such as the feedback voltage of the switching power supply system, which is suitable for the scenario where the switching frequency in the flyback switching power supply changes with the load, thereby broadening the applicable scenarios.

[0027] In a third aspect, the present application provides a switching power supply system based on the control method of the switching power supply system according to the first aspect, comprising:

[0028] Power tube;

[0029] A protection circuit, wherein the protection circuit is used to receive the feedback voltage;

[0030] A driving circuit, the driving circuit is connected to the power tube, the driving circuit is used to output the driving voltage signal, and the driving voltage signal is used to control the power tube to conduct;

[0031] A frequency jitter circuit, wherein the second input terminal of the frequency jitter circuit is connected to the output terminal of the protection circuit, the third input terminal of the frequency jitter circuit is used to receive the feedback voltage, the fourth input terminal of the frequency jitter circuit is connected to the output terminal of the drive circuit, and the frequency jitter circuit is used to output the reference voltage.

[0032] According to the switching power supply system provided in the embodiment of the present application, the working states of the components included in the frequency jittering circuit are adjusted by the feedback voltage, driving voltage signal and input AC voltage of the switching power supply system in the current switching cycle to change the voltage output by the frequency jittering circuit, and then determine the reference voltage in the next switching cycle, thereby changing the switching frequency in the next switching cycle to achieve switching frequency jittering, thereby reducing the electromagnetic interference of the switching power supply; and the switching frequency is dynamically adjusted according to signals such as the feedback voltage of the switching power supply system, which is suitable for scenarios in which the switching frequency in a flyback switching power supply changes with load changes, thereby broadening the applicable scenarios.

[0033] In a switching power supply system according to an embodiment of the present application, the frequency jitter circuit includes:

[0034] A plurality of first resistors connected in series;

[0035] The first MOS tube;

[0036] a second MOS tube, wherein the source of the first MOS tube is connected to the source of the second MOS tube, and the gate of the first MOS tube is connected to the drain of the first MOS tube and the gate of the second MOS tube respectively;

[0037] a plurality of first switches, one end of each of the first switches being connected to a side of a first resistor corresponding to the first switch close to the drain of the second MOS transistor, and the first switch being used to control the first resistor to be connected to the frequency jitter circuit;

[0038] An operational amplifier, wherein the non-inverting input terminal of the operational amplifier is used to receive the feedback voltage, and the inverting input terminal of the operational amplifier is connected to the output terminal of the operational amplifier;

[0039] a second resistor, one end of which is connected to the inverting input end of the operational amplifier and the drain of the first MOS tube respectively, and the output end of the operational amplifier is grounded via the second resistor, and the other end of the second resistor is grounded;

[0040] a fourth resistor, the fourth resistor being connected in series with the plurality of first resistors, and one end of the fourth resistor being grounded;

[0041] An output port, the other end of the first switch is connected to the output port, and the output port is used to output the reference voltage.

[0042] The switching power supply system of one embodiment of the present application further includes:

[0043] A line voltage detection circuit, wherein the first input end of the frequency jitter circuit is connected to the output end of the line voltage detection circuit, and the line voltage detection circuit is used to receive an input AC voltage.

[0044] In a fifth aspect, the present application provides a non-transitory computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the control method of the switching power supply system as described in the first aspect above is implemented.

[0045] In a sixth 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 used to run a program or instruction to implement the control method of the switching power supply system as described in the first aspect.

[0046] In a seventh aspect, the present application provides a computer program product, including a computer program, which, when executed by a processor, implements the control method of the switching power supply system as described in the first aspect above.

[0047] The above one or more technical solutions in the embodiments of the present application have at least one of the following technical effects:

[0048] The working states of the components included in the frequency jittering circuit are adjusted by the feedback voltage, drive voltage signal and input AC voltage of the switching power supply system in the current switching cycle to change the voltage output by the frequency jittering circuit, thereby determining the reference voltage in the next switching cycle, thereby changing the switching frequency in the next switching cycle to achieve switching frequency jittering, thereby reducing the electromagnetic interference of the switching power supply; and the switching frequency is dynamically adjusted according to signals such as the feedback voltage of the switching power supply system, which is suitable for scenarios where the switching frequency in a flyback switching power supply changes with load changes, broadening the applicable scenarios.

[0049] Furthermore, by detecting the level of the input AC voltage, the on and off of the second switch is controlled, thereby changing the resistance value of the resistor in the frequency jitter circuit, so that the jitter amplitude of the reference voltage can be changed according to the level of the input AC voltage, thereby avoiding the situation where the valley locking fails when the input AC voltage is low, causing the power tube to alternately conduct at adjacent valleys and generate audio noise.

[0050] Furthermore, by determining that the switching power supply system is in an abnormal working state, the reference voltage in each subsequent switching cycle is determined to be a constant value, so that the reference voltage does not jitter, thereby preventing the switching frequency from jittering, thereby avoiding the situation where the primary side peak current is too large and the transformer is saturated.

[0051] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] 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:

[0053] Figure 1 This is one of the structural schematic diagrams of the switching power supply system provided in the embodiment of the present application;

[0054] Figure 2 This is the second structural schematic diagram of the switching power supply system provided in the embodiment of the present application;

[0055] Figure 3 This is the third structural diagram of the switching power supply system provided in the embodiment of the present application;

[0056] Figure 4 This is the fourth structural diagram of the switching power supply system provided in the embodiment of the present application;

[0057] Figure 5 This is the fifth structural diagram of the switching power supply system provided in the embodiment of the present application;

[0058] Figure 6 This is the sixth structural diagram of the switching power supply system provided in the embodiment of the present application;

[0059] Figure 7 This is one of the principle schematic diagrams of the control method of the switching power supply system provided in the embodiment of the present application;

[0060] Figure 8 This is the second principle schematic diagram of the control method of the switching power supply system provided in the embodiment of the present application;

[0061] Fig. 9 This is one of the flow charts of the control method of the switching power supply system provided in the embodiment of the present application;

[0062] Fig.10 This is the second flow chart of the control method of the switching power supply system provided in the embodiment of the present application;

[0063] Fig.11 is a schematic diagram of the structure of a control device for a switching power supply system provided in an embodiment of the present application;

[0064] Fig.12 It is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0065] The following will be combined with the drawings in the embodiments of the present application to clearly describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments in the present application belong to the scope of protection of this application.

[0066] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0067] In the following, in combination with the accompanying drawings, the control method of the switching power supply system, the control device of the switching power supply system, the electronic device and the readable storage medium provided in the embodiments of the present application are described in detail through specific embodiments and their application scenarios.

[0068] The control method of the switching power supply system may be applied to a terminal, and may be specifically executed by hardware or software in the terminal.

[0069] 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.

[0070] The control method of the switching power system provided in the embodiment of the present application, the execution subject of the control method of the switching power system may be the switching power system, or may be an electronic device connected to the switching power system, or may be a functional module or functional entity in the switching power system or the electronic device that can implement the control method of the switching power system. The electronic devices mentioned in the embodiment of the present application include but are not limited to mobile phones, tablet computers, computers, cameras and wearable devices, etc. The control method of the switching power system provided in the embodiment of the present application is described below by taking the electronic device as the execution subject as an example.

[0071] like Fig.10 As shown, the control method of the switching power supply system includes: step S1, step S2 and step S3.

[0072] It should be noted that the control method of the switching power supply system can be applied to a switching power supply system.

[0073] The flyback switching power supply controls the power tube to turn on when the drain voltage is the lowest, that is, a quasi-resonant (QR) control method is adopted.

[0074] After the primary power tube is disconnected, the secondary winding begins to discharge. When the secondary current drops to 0, the LC circuit formed by the primary winding and the parasitic capacitance of the power tube begins to resonate.

[0075] The switching power supply system may be a flyback switching power supply.

[0076] A switching power supply is a high-frequency electric energy conversion device and a type of power supply.

[0077] Switching power supplies are used to convert a voltage level into the voltage or current required by the user through different forms of architecture.

[0078] Switching power supplies can be used in areas such as fast charging, adapters and chargers.

[0079] The power tube control system may include a power tube, a primary winding inductor corresponding to the power tube, and a primary power tube parasitic capacitor.

[0080] Step S1, obtaining a feedback voltage corresponding to a load of a switching power supply system in a current switching cycle, an input AC voltage of the switching power supply system, and a driving voltage signal of the switching power supply system in the current switching cycle.

[0081] In this step, the switching cycle includes the on-time and demagnetization time of the power tube.

[0082] The current switching cycle is the cycle in which the power tube needs to be turned on or has been turned on.

[0083] The feedback voltage is the voltage fed back to the primary circuit by the optocoupler.

[0084] The feedback voltage is positively correlated with the load. Specifically, when the load increases, the feedback voltage increases; when the load decreases, the feedback voltage decreases.

[0085] The input AC voltage is the AC voltage input to the switching power supply system. In actual implementation, when the switching power supply system includes a high-voltage pin, the AC input voltage information can be directly obtained through the high-voltage pin.

[0086] By setting the appropriate threshold, it is possible to distinguish whether the AC voltage input to the switching power supply system is high voltage or low voltage.

[0087] The driving voltage signal changes accordingly based on the conduction state of the power tube included in the switching power supply system.

[0088] When the driving voltage signal is at a high level, the power tube is turned on; when the driving voltage signal is at a low level, the power tube is turned off.

[0089] When the conduction time of the power tube changes, the duration of the high level of the driving voltage signal will also change accordingly.

[0090] Step S2: determining a reference voltage of the switching power supply system output by a frequency jitter circuit included in the switching power supply system in the next switching cycle based on the feedback voltage, the driving voltage signal and the input AC voltage.

[0091] In this step, the reference voltage is used to control the conduction time of the power tube. The waveform of the reference voltage is as follows: Figure 8 Medium V ref shown.

[0092] For example, the shutdown time of the power tube can be determined by comparing the reference voltage and the primary voltage signal.

[0093] Among them, the primary current is the current signal corresponding to the primary circuit, and the primary voltage signal is the voltage signal corresponding to the primary current, such as Figure 8 Medium V CS shown.

[0094] In the actual implementation process, when the primary voltage signal is greater than the reference voltage, the power tube can be controlled to be turned off.

[0095] For example, when the reference voltage increases, the time taken for the primary voltage signal to reach the reference voltage will increase accordingly, and the conduction time of the power tube will also increase.

[0096] The reference voltage in the next cycle can be determined based on the feedback voltage, the driving voltage signal and the input AC voltage, thereby changing the conduction time of the power tube.

[0097] When the operating parameters of the frequency jitter circuit are different, the magnitude of the reference voltage output by the frequency jitter circuit is also different.

[0098] By setting a frequency jitter circuit, when the output voltage of the frequency jitter circuit jitters, the reference voltage can jitter accordingly.

[0099] Step S3: adjusting the switching frequency of the switching power supply system in the next switching cycle based on the reference voltage in the next switching cycle.

[0100] In this step, when the reference voltage changes, the switching frequency will also change accordingly.

[0101] For example, when the reference voltage decreases, the on-time of the power tube decreases, the switching cycle decreases, and the switching frequency increases; when the reference voltage increases, the on-time of the power tube increases, the switching cycle increases, and the switching frequency decreases.

[0102] In the present application, the reference voltage of the switching power supply system in the next switching cycle is determined by the feedback voltage, input AC voltage and driving voltage signal of the current switching cycle corresponding to the switching power supply system in the current switching cycle. When the system is in normal working condition, the reference voltage in each switching cycle may be different, and the conduction time of the power tube in each switching cycle is also different, so that the switching frequency corresponding to each switching cycle is also different, that is, the jitter of the switching frequency is achieved, so that the switching frequency can vary within a certain range, and the system spectrum energy is dispersed to different frequency bands, thereby reducing the electromagnetic interference generated by the switching power supply system to the outside.

[0103] According to the control method of the switching power supply system provided in the embodiment of the present application, the working state of the components included in the frequency jittering circuit is adjusted by the feedback voltage, driving voltage signal and input AC voltage of the switching power supply system in the current switching cycle to change the voltage output by the frequency jittering circuit, and then determine the reference voltage in the next switching cycle, thereby changing the switching frequency in the next switching cycle to achieve switching frequency jittering, thereby reducing the electromagnetic interference of the switching power supply; and the switching frequency is dynamically adjusted according to the feedback voltage and other signals of the switching power supply system, which is suitable for the scenario where the switching frequency in the flyback switching power supply changes with the load, thereby broadening the applicable scenarios.

[0104] In some embodiments, step S2 may include:

[0105] When it is determined based on the feedback voltage that the switching power supply system is in a normal working state, adjusting the operating parameters of the frequency jitter circuit included in the switching power supply system based on the feedback voltage, the drive voltage signal and the input AC voltage;

[0106] Based on the voltage output by the adjusted frequency jitter circuit, a reference voltage of the switching power supply system in the next switching cycle is determined.

[0107] In this embodiment, whether the switching power supply system is in a normal working state can be determined based on the feedback voltage.

[0108] For example, the operating state of the switching power supply system can be determined by judging whether the feedback voltage exceeds a set threshold.

[0109] When the feedback voltage does not exceed the set threshold, it can be determined that the switching power supply system is in a normal working state.

[0110] When the feedback voltage exceeds the set threshold, that is, the load in the switching power supply system is heavy, it can be determined that the switching power supply system is in an abnormal working state. For example, the switching power supply system may have an output short circuit or an output overload.

[0111] In some embodiments, the operating parameters of the frequency jittering circuit can be changed by controlling the on / off state of the first switch to control the first resistor corresponding to the first switch to be connected to the frequency jittering circuit.

[0112] In some embodiments, an alternative circuit may be provided to change the operating parameters of the frequency jittering circuit. For example, a voltage source may be provided in the alternative circuit, and the voltage output by the frequency jittering circuit may be adjusted by adjusting the output of the voltage source.

[0113] In some embodiments, adjusting the operating parameters of the frequency jitter circuit included in the switching power supply system based on the feedback voltage, the driving voltage signal and the input AC voltage may include:

[0114] Input the feedback voltage to the non-inverting input terminal of the operational amplifier;

[0115] Based on the driving voltage signal, a target switch among the plurality of first switches is controlled to be closed, so as to control a first resistor corresponding to the target switch to be connected to the frequency jitter circuit.

[0116] like Figure 5 As shown, the frequency jitter circuit may include: a plurality of first resistors connected in series and a plurality of first switches for controlling the first resistors to access the frequency jitter circuit, an operational amplifier, a first MOS transistor, a second MOS transistor and an output port.

[0117] Among them, the first resistors are R f1 ……R fn , multiple first switches are S1...Sn.

[0118] The resistance values ​​of the multiple first resistors may be equal or unequal, which is not limited in the present application.

[0119] The second resistor R s One end of is respectively connected to the inverting input end of the operational amplifier OP and the drain of the first MOS tube, and the output end of the operational amplifier is grounded via the second resistor.

[0120] The first resistors are connected to the fourth resistor R e Ground.

[0121] One end of the first switch is connected to a side of a first resistor corresponding to the first switch close to the drain of the second MOS tube, and the other end of the first switch is connected to the output port.

[0122] The source of the first MOS tube is connected to the source of the second MOS tube, and the gate of the first MOS tube is connected to the drain of the first MOS tube and the gate of the second MOS tube respectively.

[0123] The first MOS tube and the second MOS tube can be used as a current mirror. A current proportional to the feedback voltage can be obtained through the operational amplifier and the second resistor. After being copied by the current mirror, it can flow through multiple first resistors and the fourth resistor to obtain a reference voltage proportional to the feedback voltage.

[0124] The non-inverting input terminal of the operational amplifier is used to receive the feedback voltage.

[0125] Based on the driving voltage signal, a target switch among the plurality of first switches can be controlled to be closed, thereby controlling the first resistor corresponding to the target switch to be connected to the frequency jitter circuit.

[0126] For example, when the first switch Sn is closed, the resistor R f1 ……R fn-1 Access the frequency jitter circuit.

[0127] When the number of first resistors connected to the frequency jittering circuit is different, the magnitude of the reference voltage output by the frequency jittering circuit is also different.

[0128] In some embodiments, controlling a target switch among the plurality of first switches to be closed based on the driving voltage signal may include:

[0129] When a falling edge of a driving voltage signal corresponding to a p-th switching cycle among the multiple switching cycles is detected, controlling a-an+p-th first switches among the multiple first switches to be closed;

[0130] When a falling edge of a driving voltage signal corresponding to the qth switching period among a plurality of switching periods is detected, an+n-a+1-qth first switch among a plurality of first switches is controlled to be closed.

[0131] In this embodiment, the falling edge of the driving voltage signal may be the moment when the driving voltage signal changes from a high level (digital “1”) to a low level (digital “0”).

[0132] The number of the plurality of switching cycles is m, and the number of the plurality of first switches is n, wherein m and n are both positive integers.

[0133] For example, m may be 10, n may be 5, or may be other values, which are not limited in the present application.

[0134] p is a positive integer less than or equal to m, and an-a+1≤p≤an+na≤m, where a is 0 or a positive even number.

[0135] like Figure 7 As shown, in the actual implementation process, Q1 ... Qn respectively control the first switches S1 ... Sn to be closed, and when Qn is at a high level, the first switch Sn is closed.

[0136] For example, when a is 0, 1≤p≤n≤m, and when p is n, when the falling edge of the driving voltage signal corresponding to the nth switching cycle in multiple switching cycles is detected, Qn is a high level, and the nth first switch among the multiple first switches can be controlled to close, that is, the first switch Sn corresponding to Qn is closed.

[0137] When a is 2, 2n-1≤p≤3n-2≤m. When p is 2n-1, when the falling edge of the driving voltage signal corresponding to the 2n-1th switching cycle in multiple switching cycles is detected, Q1 is at a high level, which can control the first first switch among the multiple first switches to be closed, that is, the first switch S1 corresponding to Q1 is closed.

[0138] q is a positive integer, and an-a+1<q≤an+na-1≤m, where a is a positive odd number.

[0139] like Figure 7 As shown, when a is 1, n<q≤2n-2≤m, and when q is n+1, when the falling edge of the driving voltage signal corresponding to the n+1th switching cycle in multiple switching cycles is detected, Qn-1 is at a high level, which can control the n-1th first switch among the multiple first switches to be closed, that is, the first switch Sn-1 corresponding to Qn-1 is closed.

[0140] When a is 3, 3n-2<q≤4n-4≤m. When q is 3n-1, when the falling edge of the driving voltage signal corresponding to the 3n-1th switching cycle in multiple switching cycles is detected, Qn-1 is at a high level, which can control the n-1th first switch among the multiple first switches to be closed, that is, the first switch Sn-1 corresponding to Qn-1 is closed.

[0141] like Figure 5 As shown, the frequency jitter circuit may further include a switch control circuit. Under the control of the switch control circuit, the plurality of first switches may be closed and opened in a certain regularity in each switching cycle, thereby adjusting the magnitude of the reference voltage.

[0142] In the actual implementation process, Figure 6As shown, the driving voltage signal (DRV signal) can be input into the bidirectional shift register. When the falling edge of the DRV signal is detected, the output signal Q1 is high; when the falling edge of the DRV signal arrives in the next switching cycle, the output signal Q1 is low and Q2 is high; according to this rule, when the falling edge of the DRV signal arrives in the subsequent switching cycle, the signal whose output becomes high is shifted right in sequence; until the output signal Qn becomes high, when the falling edge of the DRV signal arrives in the next switching cycle, the output signal Qn is low and Qn-1 becomes high; then according to this rule, when the falling edge of the DRV signal arrives in the subsequent switching cycle, the signal whose output becomes high is shifted left in sequence until the output signal Q1 becomes high, and the signal whose output becomes high is shifted right in sequence again, and this cycle repeats. The working waveforms of the DRV signal and the signals Q1, Q2...Qn are as shown in FIG. Figure 7 shown.

[0143] The output signals Q1, Q2, ..., Qn are respectively sent to the AND gate, and another input signal of the AND gate is the inverted signal obtained by the protection signal Pro through the inverter.

[0144] When the switching power supply system is determined to be in normal working state, the protection signal Pro is low, and the inverse signal of Pro is high. At this time, the level of the AND gate output signal only depends on the level of the bidirectional shift register output signal, that is, when Qn is high, the corresponding Sn_EN is high.

[0145] As the output signals Q1, Q2, ..., Qn are switched to high level in each switching cycle, the first switches S1, S2, ..., Sn are also closed and opened accordingly. Figure 8 As shown, the reference voltage V output by the frequency jitter circuit ref The primary voltage signal corresponding to the primary peak current keeps shaking, which changes the conduction time of the power tube, thereby achieving the switching frequency F sw jitter.

[0146] According to the control method of the switching power supply system provided in the embodiment of the present application, the falling edge of the driving voltage signal in each switching cycle is detected to control the closing and opening of multiple switches in each switching cycle, thereby adjusting the size of the reference voltage in each switching cycle, and jittering the reference voltage corresponding to multiple switching cycles, so that the switching frequency can be jittered. The control logic is simple and easy, and the reference voltage can be adjusted based on the actual working signal of the switching cycle system in each switching cycle. It is suitable for the scenario where the switching frequency in the flyback switching power supply changes with the load, which broadens the applicable scenarios.

[0147] In some embodiments, adjusting the operating parameters of the frequency jitter circuit included in the switching power supply system based on the feedback voltage, the driving voltage signal and the input AC voltage may include:

[0148] When the number of first resistors connected to the frequency jitter circuit increases among the plurality of first resistors, the reference voltage increases;

[0149] When the number of the first resistors connected to the frequency jitter circuit among the plurality of first resistors decreases, the reference voltage decreases.

[0150] In this embodiment, the reference voltage varies within a first range, and the first range may be determined based on the number of first resistors connected to the frequency jittering circuit.

[0151] When different first switches are closed, the number of first resistors connected to the frequency jitter circuit is also different, so that the resistance value in the frequency jitter circuit is different, thereby adjusting the magnitude of the reference voltage.

[0152] like Figure 5 As shown, when the number of first resistors connected to the frequency jittering circuit increases, the reference voltage output by the frequency jittering circuit increases, that is, when the first switch Sn is closed, the number of first resistors connected to the frequency jittering circuit is the largest, and the reference voltage reaches the upper limit value.

[0153] When the number of first resistors in the frequency jittering circuit decreases, the reference voltage output by the frequency jittering circuit decreases, that is, when the first switch S1 is closed, the number of first resistors in the frequency jittering circuit is the least, and the reference voltage reaches the lower limit.

[0154] In some embodiments, step S2 may include:

[0155] When the input AC voltage is greater than the target threshold, controlling the second switch to close;

[0156] When the input AC voltage is less than or equal to the target threshold, the second switch is controlled to be disconnected.

[0157] In this embodiment, if Figure 5 As shown, a third resistor R may be connected in series between the plurality of first resistors and the fourth resistor. e0 , the third resistor is connected in parallel with a second switch S0.

[0158] When the second switch is closed, the third resistor is not connected to the frequency jitter circuit; when the second switch is open, the third resistor is connected to the frequency jitter circuit.

[0159] The target threshold value may be user-defined. For example, the target threshold value may be 160V, or 170V, or other values, which are not limited in this application.

[0160] When the input AC voltage is greater than the target threshold, it can be considered that the input AC voltage is high, and the second switch can be controlled to be closed.

[0161] When the input AC voltage is less than or equal to the target threshold, it can be considered that the input AC voltage is low, and the second switch can be controlled to be disconnected.

[0162] like Figure 6 As shown, in the actual implementation process, an interface of the frequency jitter circuit is used to receive an ACH signal, wherein, when the input AC voltage is high, the ACH signal is at a high level, and when the input AC voltage is low, the ACH signal is at a low level.

[0163] When the ACH signal is at a high level, the switch enable signal S0_EN is high, and the second switch S0 is closed.

[0164] When the ACH signal is at a low level, the switch enable signal S0_EN is low, and the second switch S0 is turned off.

[0165] When the input AC voltage signal is of different levels, the variation range of the reference voltage is also different.

[0166] The variation amplitude of the reference voltage in each cycle can be determined based on the number of resistors connected in the frequency reference circuit.

[0167] For example, the variation amplitude of the reference voltage may be determined based on a target ratio between the sum of the resistance values ​​of the first resistor connected to the frequency reference circuit and the sum of the resistance values ​​of the third resistor and the fourth resistor connected to the frequency reference circuit.

[0168] When the switch Sn is closed, R f1 ……R fn-1 Both are connected to the frequency jitter circuit (or switch S1 is closed). When the input AC voltage is high, S0 is closed and R e0 If the frequency jitter circuit is not connected, the target ratio is larger, and the difference between the upper limit value (lower limit value) that the reference voltage can reach and the average value of the reference voltage is larger, that is, the variation range of the reference voltage is larger.

[0169] When the switch Sn is closed, R f1 ……R fn-1 Both are connected to the frequency jitter circuit (or switch S1 is closed). When the input AC voltage is low, S0 is disconnected and R e0 When the frequency jitter circuit is connected, the target ratio is smaller, and the difference between the upper limit value (lower limit value) that the reference voltage can reach and the average value of the reference voltage is smaller, that is, the variation range of the reference voltage is smaller.

[0170] For example, the reference voltage changes within each cycle by: Among them, R e is the fourth resistor, R fi is the first resistor, i.e. Rf1 ……R fn-1 Any resistor, V ref_avg is the average value of the reference voltage, and n is the number of the plurality of first resistors.

[0171] When the input AC voltage is high, based on the above formula, the jitter amplitude of the reference voltage is large (for example, the jitter amplitude is ±8%), that is, Wherein, ΔV is the difference between the upper limit value of the reference voltage and the average value of the reference voltage.

[0172] When the input AC voltage is low, the ACH signal is at a low level, and S0_EN is at a low level, the first switch S0 is disconnected, and the third resistor R e0 The frequency jitter circuit is connected, and the amplitude of each cycle jitter is When the input AC voltage is relatively low, the jitter amplitude is reduced (for example, the jitter amplitude is ±4%), that is, Wherein, ΔV is the difference between the upper limit value of the reference voltage and the average value of the reference voltage.

[0173] During the research and development process, the inventors discovered that in the related technology, when the jitter amplitude of the peak current is large and the input AC voltage is low, the bus voltage fluctuates greatly, which will cause fluctuations in the feedback voltage after loop regulation, and may cause valley locking failure, causing the power tube to alternately conduct at adjacent valleys, thereby generating audio noise.

[0174] In the present application, a reference voltage is generated by a frequency jitter circuit, and the reference voltage is controlled to change a certain amplitude in each switching cycle, so that the reference voltage presents an amplitude change within a set range in a complete frequency jitter cycle, wherein, when the input AC voltage is high, the jitter amplitude of the reference voltage in the complete frequency jitter cycle can be ±8%, thereby reducing the impact of electromagnetic interference; when the input AC voltage is low, the jitter amplitude of the reference voltage in the complete frequency jitter cycle can be ±4%, which can effectively avoid valley locking failure, thereby avoiding the power tube alternately turning on at adjacent valleys and generating audio noise.

[0175] According to the control method of the switching power supply system provided in the embodiment of the present application, the on-off of the second switch is controlled by detecting the level of the input AC voltage, thereby changing the resistance value of the resistor in the frequency jitter circuit, so that the jitter amplitude of the reference voltage can be changed according to the level of the input AC voltage, thereby avoiding the situation where the valley locking fails when the input AC voltage is low, causing the power tube to alternately conduct at adjacent valleys and generate audio noise.

[0176] In some embodiments, step S3 may include:

[0177] Based on the reference voltage, adjusting the time taken by the primary voltage signal corresponding to the switching power supply system to reach the reference voltage;

[0178] Within the time taken by the primary voltage signal to reach the reference voltage, the power tube included in the switching power supply system is controlled to be turned on, so that the switching frequency in the next switching cycle fluctuates within the second range.

[0179] In this embodiment, the primary voltage signal is the primary current sampling signal on the sampling resistor, such as Figure 8 Medium V CS shown.

[0180] The primary voltage signal is a ramp voltage signal with a positive slope. When the power tube is turned on, the primary voltage signal will continue to increase until it exceeds the reference voltage, and then the power tube is controlled to be turned off. At this time, the corresponding reference voltage V ref That is the peak voltage V corresponding to the primary current sampling signal CS_PK , where V CS_PK =I CS_PK *R CS , I CS_PK is the primary peak current, R CS It is the source end sampling resistor of the power tube.

[0181] When the reference voltage changes, the time it takes for the primary voltage signal to reach the reference voltage will also change.

[0182] When the switching power supply system is in a normal working state, the reference voltage may jitter, thereby causing the switching frequency to jitter.

[0183] For example, when the reference voltage increases, the time taken by the primary voltage signal to reach the reference voltage will increase, thereby extending the conduction time of the power tube; when the reference voltage decreases, the time taken by the primary voltage signal to reach the reference voltage will decrease, thereby shortening the conduction time of the power tube.

[0184] The second range is the jitter amplitude range of the switching frequency within the entire jitter cycle.

[0185] The switching frequency will change by a certain amplitude in each switching cycle, so that the switching frequency will jitter in the entire jitter cycle, and the jitter range of the switching frequency is the second range.

[0186] like Figure 8 As shown, when the reference voltage is the lower limit value of the first range, the switching frequency reaches the upper limit value of the second range; when the reference voltage is the upper limit value of the first range, the switching frequency reaches the lower limit value of the second range.

[0187] In some embodiments, step S2 may include:

[0188] When the switching power supply system is determined to be in an abnormal operating state based on the feedback voltage, the frequency jitter circuit outputs the average of the upper limit value and the lower limit value of the first range, and determines the average as the reference voltage of the switching power supply system in the next switching cycle.

[0189] In this embodiment, the first range is a variation range corresponding to a reference voltage determined based on a feedback voltage, a driving voltage signal and an input AC voltage when the switching power supply system is in a normal working state.

[0190] When the switching power supply system is in a normal working state, it can be determined that the reference voltage varies within the first range, so that the upper limit value and the lower limit value of the first range can be determined.

[0191] The abnormal working state of the switching power supply system may include: output short circuit or output overload.

[0192] like Figure 1 or Figure 2 As shown in the figure, when the switching power supply system is abnormal, the output circuit will be larger, that is, the load will be heavier. At this time, the current fed back to the primary side through the optocoupler and flowing into the FB pin will decrease, and the voltage value obtained at the FB pin is inversely proportional to the current. The feedback voltage V FB Increase.

[0193] When the feedback voltage is greater than the set threshold, it can be determined that the switching power supply system is in an abnormal operating state.

[0194] like Figure 4 As shown, the protection circuit can receive a feedback voltage, thereby outputting a protection signal Pro. When the feedback voltage is greater than a set threshold, the protection signal Pro output by the protection circuit is a high level.

[0195] like Figure 6 As shown, the switch control circuit can receive a protection signal Pro. When the protection signal Pro is at a high level, the switch enable signal S(n+1) / 2_EN is at a high level, and the primary peak current does not jitter. The average of the upper limit value and the lower limit value of the first range can be determined as the reference voltage in the next switching cycle.

[0196] For example, when the input AC voltage is high, the ACH signal is at a high level, then S0_EN is high, and the first switch S0 is closed, thereby connecting the third resistor R e0 Short circuit, the resistance in the access frequency jitter circuit is reduced. Among them, V ref_avg is the reference voltage for the next switching cycle, V FB is the feedback voltage, R s is the second resistor, R e is the fourth resistor, R fiis the first resistor.

[0197] According to the control method of the switching power supply system provided in the embodiment of the present application, by determining that the switching power supply system is in an abnormal working state, the reference voltage in each subsequent switching cycle is determined to be a constant value, so that the reference voltage does not jitter, thereby preventing the switching frequency from jittering, thereby avoiding the situation where the primary side peak current is too large and the transformer is saturated.

[0198] The control method of the switching power system provided in the embodiment of the present application can be executed by a control device of the switching power system. In the embodiment of the present application, the control device of the switching power system executing the control method of the switching power system is taken as an example to illustrate the control device of the switching power system provided in the embodiment of the present application.

[0199] An embodiment of the present application also provides a control device for a switching power supply system.

[0200] like Fig.11 As shown, the control device of the switching power supply system includes: a first processing module 1110 , a second processing module 1120 and a third processing module 1130 .

[0201] The first processing module 1110 is used to obtain a feedback voltage corresponding to a load of the switching power supply system in a current switching cycle, an input AC voltage of the switching power supply system, and a driving voltage signal of the switching power supply system in the current switching cycle; the driving voltage signal changes correspondingly based on the conduction state of the power tube included in the switching power supply system;

[0202] A second processing module 1120, configured to determine a reference voltage of the switching power supply system output by a frequency jitter circuit included in the switching power supply system in a next switching cycle based on the feedback voltage, the driving voltage signal and the input AC voltage;

[0203] The third processing module 1130 is used to adjust the switching frequency of the switching power supply system in the next switching cycle based on the reference voltage in the next switching cycle.

[0204] According to the control device of the switching power supply system provided in the embodiment of the present application, the working state of the components included in the frequency jittering circuit is adjusted by the feedback voltage, driving voltage signal and input AC voltage of the switching power supply system in the current switching cycle to change the voltage output by the frequency jittering circuit, and then determine the reference voltage in the next switching cycle, thereby changing the switching frequency in the next switching cycle to achieve switching frequency jittering, thereby reducing the electromagnetic interference of the switching power supply; and the switching frequency is dynamically adjusted according to signals such as the feedback voltage of the switching power supply system, which is suitable for the scenario where the switching frequency in the flyback switching power supply changes with the load, thereby broadening the applicable scenarios.

[0205] In some embodiments, the second processing module 1120 may also be used to:

[0206] When it is determined based on the feedback voltage that the switching power supply system is in a normal working state, adjusting the operating parameters of the frequency jitter circuit included in the switching power supply system based on the feedback voltage, the drive voltage signal and the input AC voltage;

[0207] Based on the voltage output by the adjusted frequency jitter circuit, a reference voltage of the switching power supply system in the next switching cycle is determined.

[0208] In some embodiments, the frequency jitter circuit includes: a plurality of first resistors connected in series and a plurality of first switches for controlling the first resistors to be connected to the frequency jitter circuit, an operational amplifier, a first MOS tube, a second MOS tube and an output port, wherein the output port is used to output a reference voltage of the switching power supply system in the next switching cycle; one end of the second resistor is respectively connected to the inverting input end of the operational amplifier and the drain of the first MOS tube, and the output end of the operational amplifier is grounded via the second resistor, and the plurality of first resistors are grounded via the fourth resistor, one end of the first switch is connected to a side of the first resistor corresponding to the first switch close to the drain of the second MOS tube, the other end of the first switch is connected to the output port, the source of the first MOS tube is connected to the source of the second MOS tube, and the gate of the first MOS tube is respectively connected to the drain of the first MOS tube and the gate of the second MOS tube; the second processing module 1120 can also be used for:

[0209] Input the feedback voltage to the non-inverting input terminal of the operational amplifier;

[0210] Based on the driving voltage signal, a target switch among the plurality of first switches is controlled to be closed, so as to control a first resistor corresponding to the target switch to be connected to the frequency jitter circuit.

[0211] In some embodiments, the number of the plurality of switching cycles is m, the number of the plurality of first switches is n, wherein m and n are both positive integers; the second processing module 1120 may also be used for:

[0212] When a falling edge of a driving voltage signal corresponding to a p-th switching cycle in a plurality of switching cycles is detected, controlling a-an+p-th first switches among a plurality of first switches to be closed, wherein p is a positive integer less than or equal to m, and an-a+1≤p≤an+na≤m, and a is 0 or a positive even number;

[0213] When the falling edge of the driving voltage signal corresponding to the qth switching cycle in multiple switching cycles is detected, the an+n-a+1-qth first switch in the multiple first switches is controlled to be closed, where q is a positive integer, an-a+1<q≤an+na-1≤m, and a is a positive odd number.

[0214] In some embodiments, a third resistor is connected in series between the plurality of first resistors and the fourth resistor, and a second switch is connected in parallel to the third resistor; the second processing module 1120 may also be used for:

[0215] When the input AC voltage is greater than the target threshold, controlling the second switch to close;

[0216] When the input AC voltage is less than or equal to the target threshold, the second switch is controlled to be disconnected.

[0217] In some embodiments, the second processing module 1120 may also be used to:

[0218] When the switching power supply system is determined to be in an abnormal working state based on the feedback voltage, the frequency jitter circuit outputs the average of the upper limit value and the lower limit value of the first range, and determines the average value as the reference voltage of the switching power supply system in the next switching cycle; the first range is the variation range corresponding to the reference voltage determined based on the feedback voltage, the drive voltage signal and the input AC voltage when the switching power supply system is in a normal working state. The control device of the switching power supply system in the embodiment of the present application can be an electronic device or a component in an electronic device, such as an integrated circuit or a chip. The electronic device can be a terminal or a device other than a terminal. Exemplarily, the electronic device may be a mobile phone, a tablet computer, a laptop computer, a PDA, an in-vehicle electronic device, a mobile Internet device (MID), an augmented reality (AR) / virtual reality (VR) device, a robot, a wearable device, an ultra-mobile personal computer (UMPC), a netbook or a personal digital assistant (PDA), etc. It may also be a server, a network attached storage (NAS), a personal computer (PC), a television (TV), a teller machine or a self-service machine, etc., which is not specifically limited in the embodiments of the present application.

[0219] The control device of the switching power supply system in the embodiment of the present application may be a device having an operating system. The operating system may be an Android operating system, an IOS operating system, or other possible operating systems, which are not specifically limited in the embodiment of the present application.

[0220] The control device of the switching power supply system provided in the embodiment of the present application can achieve Figures 1 to 10To avoid repetition, the various processes implemented by the method embodiment are not described here.

[0221] In some embodiments, Figure 1 As shown, an embodiment of the present application also provides a switching power supply system.

[0222] The switching power supply system may include a primary control circuit, a feedback loop, a secondary control circuit, a power tube Q1, a primary winding Np, an auxiliary winding Na, a secondary winding Ns, a first sampling resistor R CS , a second sampling resistor R1 and a third sampling resistor R2.

[0223] In this embodiment, the main structure of the primary control circuit is as follows: Figure 3 or Figure 4 As shown, the primary side control circuit may include: a valley detection circuit, a valley locking circuit, a protection circuit, a line voltage detection circuit, a frequency jitter circuit, a PWM comparator, an RS trigger and a driving circuit.

[0224] One end of the primary winding Np is connected to the input voltage Vin, and the other end is connected to the drain of the power tube Q1.

[0225] The two ends of the primary winding Np are connected to the second sampling resistor R1, the first capacitor C1 and the first output rectifier tube D1 to form an RCD peak absorption circuit.

[0226] The power tube Q1 may include a source, a drain and a gate.

[0227] One end of the primary winding Np is connected to the input voltage Vin, and the other end is connected to the drain of the power tube Q1.

[0228] The gate of the power tube Q1 is connected to the DRV pin of the primary control circuit, and the input voltage Vbulk provides a startup voltage to the chip after passing through the current limiting resistor R0.

[0229] The source of the power tube Q1 is connected to the first sampling resistor R CS , the first sampling resistor R CS The other end is grounded.

[0230] The first sampling resistor R CS One end connected to the source of the power tube Q1 is connected to the CS pin of the primary side control circuit.

[0231] The voltage on the auxiliary winding Na is in phase with the drain voltage of the power tube Q1.

[0232] The auxiliary winding Na is connected to the second sampling resistor R1 and the third sampling resistor R2 at the same end, and the other end of the auxiliary winding Na is grounded.

[0233] The connecting point of the second sampling resistor R1 and the third sampling resistor R2 is connected to the ZCD pin of the primary control circuit.

[0234] The same-name end of the secondary winding Ns is connected to the drain of the second output rectifier tube D2, and the other end of the secondary winding Ns is grounded.

[0235] The output voltage Vout is connected to the FB pin of the primary side control circuit through a feedback loop.

[0236] The secondary circuit may include: a secondary winding Ns, a second output rectifier tube D2 and a light emitting diode I1A.

[0237] The opposite end of the secondary winding Ns is grounded.

[0238] The same-name end of the secondary winding Ns is electrically connected to the anode of the second output rectifier tube D2.

[0239] The cathode of the second output rectifier tube D2 is electrically connected to the light emitting diode I1A through the fifth sampling resistor R2.

[0240] The cathode of the second output rectifier tube D2 is also grounded through the third capacitor C2.

[0241] The cathode of the second output rectifier tube D2 is electrically connected to the output capacitor Cout and can provide an output voltage Vout.

[0242] The output voltage Vout can be input to the adjustable parallel regulator TL431 after passing through the second sampling resistor R3 and the third sampling resistor R4. The output current of the adjustable parallel regulator TL431 can be fed back to the primary FB pin through the optocoupler feedback circuit, wherein the optocoupler feedback circuit may include: a light-emitting diode I1A and a primary phototransistor I1B.

[0243] A fourth capacitor C3 may be electrically connected between the light emitting diode I1A and the second sampling resistor R3.

[0244] The FB pin of the primary side control circuit is grounded through the phototransistor I1B and the fifth capacitor C5 respectively.

[0245] The auxiliary circuit may include: an auxiliary winding Na, a third output rectifier tube D3 and a second capacitor C4.

[0246] The auxiliary circuit can provide the chip with a power supply voltage VDD.

[0247] The opposite end of the auxiliary winding Na2 is grounded.

[0248] The same-name end of the auxiliary winding Na2 and the fifth sampling resistor R H and the sixth sampling resistor R L The sampling voltage signal can be input to the ZCD pin of the primary chip through electrical connection.

[0249] Figure 2An example of a switching power supply system without a high voltage pin in the primary side control circuit is given, which will not be described in detail here.

[0250] After the primary power tube is disconnected, the secondary winding begins to discharge. When the secondary current drops to 0, the LC circuit formed by the primary winding and the parasitic capacitance of the power tube begins to resonate. In the flyback switching power supply, the auxiliary winding voltage waveform has the same change trend as the power tube drain voltage waveform. During the power tube disconnection period, the resonant voltage waveform can be obtained by sampling the ZCD pin voltage. The ZCD sampling signal is input into the valley voltage detection module. Whenever the sampled voltage resonates to the valley, the valley detection circuit outputs a valley signal. The valley locking module generates a corresponding valley conduction signal based on the valley signal and load information and sends it to the RS trigger to turn on the power tube at the corresponding valley.

[0251] The line voltage detection circuit is used for receiving the input AC voltage.

[0252] The line voltage detection circuit can be used to detect the size of the AC input voltage. When the chip has a high-voltage pin, the AC input voltage information can be directly obtained through the high-voltage pin and introduced into the line voltage detection circuit after voltage division.

[0253] When the input AC voltage is a low voltage input, the line voltage detection circuit outputs an ACL signal; when the input AC voltage is a high voltage input, the line voltage detection circuit outputs an ACH signal.

[0254] In the case where the chip does not have a high voltage pin, the primary side control circuit is as follows Figure 4 As shown, the input AC voltage information can be obtained through the ZCD pin.

[0255] When the power tube is turned on, the current of the ZCD pin is proportional to the input AC voltage. Among them, R ZCD_UP is the voltage divider resistor on ZCD, N A is the number of turns of the auxiliary winding, N P is the number of turns of the primary winding.

[0256] The protection circuit is used to receive the feedback voltage, so that the abnormal working state of the system can be detected based on the feedback voltage. FB When the set threshold is exceeded, it can be determined that the switching power supply system is in an abnormal working state, and a protection signal Pro is output.

[0257] The first input terminal of the frequency jitter circuit is connected to the output terminal of the line voltage detection circuit, the second input terminal of the frequency jitter circuit is connected to the output terminal of the protection circuit, the third input terminal of the frequency jitter circuit is used to receive the feedback voltage, and the frequency jitter circuit is used to output the reference voltage.

[0258] The frequency jittering circuit is used to jitter the peak current and change the on-time of each switching cycle, thereby generating frequency jittering.

[0259] The frequency jitter circuit generates a frequency that is proportional to the feedback voltage V FB Proportional to the reference voltage V ref .

[0260] The flyback switching power supply usually adopts the peak current control mode. The positive input of the PWM comparator is the primary voltage signal V on the CS sampling resistor. CS , the inverting input terminal is the feedback voltage V FB The reference voltage is generated after passing through the frequency jitter circuit.

[0261] The primary voltage signal is a positive slope ramp voltage signal. When the power tube is turned on, the primary voltage signal increases continuously until it exceeds the reference voltage V ref When the PWM comparator outputs a high-level signal, the RS trigger output is set to low, and the power tube is turned off through the drive circuit.

[0262] like Figure 5 As shown, in some embodiments, the frequency jitter circuit may include: a plurality of first resistors R connected in series fn , a first MOS tube, a second MOS tube, a plurality of first switches Sn, an operational amplifier OP, a second resistor Rs, a third resistor R e0 , a second switch S0, a fourth resistor R e and output ports.

[0263] In this embodiment, the source of the first MOS tube is connected to the source of the second MOS tube, and the gate of the first MOS tube is connected to the drain of the first MOS tube and the gate of the second MOS tube respectively.

[0264] One end of the first switch Sn is connected to a first resistor R corresponding to the first switch Sn. fn The first switch Sn is connected to the side close to the drain of the second MOS tube, and is used to control the first resistor R fn Access the frequency jitter circuit.

[0265] The non-inverting input terminal of the operational amplifier OP is used to receive the feedback voltage, and the inverting input terminal of the operational amplifier OP is connected to the output terminal of the operational amplifier OP.

[0266] One end of the second resistor Rs is connected to the inverting input end of the operational amplifier OP and the drain of the first MOS tube respectively, and the output end of the operational amplifier OP is grounded via the second resistor Rs.

[0267] The second switch S0 and the third resistor R e0 Connect in parallel.

[0268] The third resistor R e0 and the fourth resistor R e All of them are connected with a plurality of first resistors R fn The fourth resistor R e One end is grounded.

[0269] The other end of the first switch Sn is connected to the output port, and the output port is used to output the reference voltage.

[0270] According to the switching power supply system provided in the embodiment of the present application, the working states of the components included in the frequency jittering circuit are adjusted by the feedback voltage, driving voltage signal and input AC voltage of the switching power supply system in the current switching cycle to change the voltage output by the frequency jittering circuit, and then determine the reference voltage in the next switching cycle, thereby changing the switching frequency in the next switching cycle to achieve switching frequency jittering, thereby reducing the electromagnetic interference of the switching power supply; and the switching frequency is dynamically adjusted according to signals such as the feedback voltage of the switching power supply system, which is suitable for scenarios in which the switching frequency in a flyback switching power supply changes with load changes, thereby broadening the applicable scenarios.

[0271] In some embodiments, Fig.12 As shown, an embodiment of the present application also provides an electronic device 1200, including a processor 1201, a memory 1202, and a computer program stored in the memory 1202 and executable on the processor 1201. When the program is executed by the processor 1201, each process of the control method embodiment of the above-mentioned switching power supply system is implemented, and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0272] It should be noted that the electronic devices in the embodiments of the present application include the mobile electronic devices and non-mobile electronic devices mentioned above.

[0273] An embodiment of the present application also 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 control method embodiment of the above-mentioned switching power supply system are implemented, and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0274] 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.

[0275] An embodiment of the present application also provides a computer program product, including a computer program, which implements the control method of the switching power supply system when executed by a processor.

[0276] 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.

[0277] 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 control method embodiment of the switching power supply system, and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0278] 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.

[0279] It should be noted that, in this article, the terms "comprise", "include" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements includes not only 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, the elements defined by the sentence "comprise one..." do not exclude the presence of other identical elements in the process, method, article or device including 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 reverse 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.

[0280] 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 a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a computer software product, which is stored in a storage medium (such as ROM / RAM, a disk, or an optical disk), and includes a number of instructions for a terminal (which can be a mobile phone, a computer, a server, or a network device, etc.) to execute the methods described in each embodiment of the present application.

[0281] 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 the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

[0282] In the description of this specification, the description with reference to the terms "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 schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0283] 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 spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A control method for a switching power supply system, characterized in that: include: Acquire a feedback voltage corresponding to a load of the switching power system in a current switching cycle, an input AC voltage of the switching power system, and a driving voltage signal of the switching power system in the current switching cycle; The driving voltage signal changes accordingly based on the conduction state of the power tube included in the switching power supply system; Determine, based on the feedback voltage, the drive voltage signal and the input AC voltage, a reference voltage of the switching power supply system output by a frequency jitter circuit included in the switching power supply system in the next switching cycle; Based on the reference voltage in the next switching cycle, the switching frequency of the switching power supply system in the next switching cycle is adjusted.

2. The control method of the switching power supply system according to claim 1, characterized in that: The step of determining a reference voltage of the switching power supply system in the next switching cycle output by a frequency jitter circuit included in the switching power supply system based on the feedback voltage, the driving voltage signal and the input AC voltage comprises: When it is determined that the switching power supply system is in a normal working state based on the feedback voltage, adjusting the operating parameters of the frequency jitter circuit included in the switching power supply system based on the feedback voltage, the drive voltage signal and the input AC voltage; Based on the adjusted voltage output by the frequency jitter circuit, a reference voltage of the switching power supply system in the next switching cycle is determined.

3. The control method of the switching power supply system according to claim 2, characterized in that: The frequency jitter circuit includes: a plurality of first resistors connected in series and a plurality of first switches for controlling the first resistors to be connected to the frequency jitter circuit, an operational amplifier, a first MOS transistor, a second MOS transistor and an output port, wherein the output port is used to output a reference voltage of the switching power supply system in the next switching cycle; one end of the second resistor is respectively connected to the inverting input end of the operational amplifier and the drain of the first MOS transistor, and the output end of the operational amplifier is grounded via the second resistor, the plurality of first resistors are grounded via a fourth resistor, one end of the first switch is connected to a side of the first resistor corresponding to the first switch close to the drain of the second MOS transistor, the other end of the first switch is connected to the output port, the source of the first MOS transistor is connected to the source of the second MOS transistor, and the gate of the first MOS transistor is respectively connected to the drain of the first MOS transistor and the gate of the second MOS transistor; the operating parameters of the frequency jitter circuit included in the switching power supply system are adjusted based on the feedback voltage, the driving voltage signal and the input AC voltage, including: Inputting the feedback voltage to the non-inverting input terminal of the operational amplifier; Based on the driving voltage signal, a target switch among the plurality of first switches is controlled to be closed, so as to control a first resistor corresponding to the target switch to be connected to the frequency jitter circuit.

4. The control method of the switching power supply system according to claim 3, characterized in that: The number of the plurality of switching cycles is m, the number of the plurality of first switches is n, wherein m and n are both positive integers; and controlling the target switch among the plurality of first switches to close based on the driving voltage signal comprises: When a falling edge of a driving voltage signal corresponding to a p-th switching cycle in the plurality of switching cycles is detected, controlling a-an+p-th first switches in the plurality of first switches to be closed, wherein p is a positive integer less than or equal to m, an-a+1≤p≤an+na≤m, and a is 0 or a positive even number; When the falling edge of the driving voltage signal corresponding to the qth switching cycle in the multiple switching cycles is detected, the an+n-a+1-qth first switch in the multiple first switches is controlled to be closed, where q is a positive integer, an-a+1<q≤an+na-1≤m, and a is a positive odd number.

5. The control method of the switching power supply system according to claim 3, characterized in that: A third resistor is connected in series between the plurality of first resistors and the fourth resistor, and a second switch is connected in parallel to the third resistor; and adjusting the operating parameters of the frequency jitter circuit included in the switching power supply system based on the feedback voltage, the drive voltage signal and the input AC voltage comprises: When the input AC voltage is greater than a target threshold, controlling the second switch to close; When the input AC voltage is less than or equal to the target threshold, the second switch is controlled to be disconnected.

6. The control method of the switching power supply system according to any one of claims 1 to 5, characterized in that: The step of determining a reference voltage of the switching power supply system in the next switching cycle output by a frequency jitter circuit included in the switching power supply system based on the feedback voltage, the driving voltage signal and the input AC voltage comprises: When the switching power supply system is determined to be in an abnormal operating state based on the feedback voltage, the frequency jitter circuit outputs the average of the upper limit value and the lower limit value of the first range, and determines the average value as the reference voltage of the switching power supply system in the next switching cycle; the first range is the variation range corresponding to the reference voltage determined based on the feedback voltage, the drive voltage signal and the input AC voltage when the switching power supply system is in a normal operating state.

7. A control device for a switching power supply system, characterized in that: include: A first processing module, used for obtaining a feedback voltage corresponding to a load of the switching power system in a current switching cycle, an input AC voltage of the switching power system, and a driving voltage signal of the switching power system in the current switching cycle; The driving voltage signal changes accordingly based on the conduction state of the power tube included in the switching power supply system; A second processing module, configured to determine a reference voltage of the switching power supply system in a next switching cycle output by a frequency jitter circuit included in the switching power supply system based on the feedback voltage, the driving voltage signal and the input AC voltage; The third processing module is used to adjust the switching frequency of the switching power supply system in the next switching cycle based on the reference voltage in the next switching cycle.

8. A switching power supply system based on the control method of the switching power supply system according to any one of claims 1 to 6, characterized in that: include: Power tube; A protection circuit, wherein the protection circuit is used to receive the feedback voltage; A driving circuit, the driving circuit is connected to the power tube, the driving circuit is used to output the driving voltage signal, and the driving voltage signal is used to control the power tube to conduct; A frequency jitter circuit, wherein the second input terminal of the frequency jitter circuit is connected to the output terminal of the protection circuit, the third input terminal of the frequency jitter circuit is used to receive the feedback voltage, the fourth input terminal of the frequency jitter circuit is connected to the output terminal of the drive circuit, and the frequency jitter circuit is used to output the reference voltage.

9. The switching power supply system according to claim 8, characterized in that: The frequency jitter circuit comprises: A plurality of first resistors connected in series; The first MOS tube; a second MOS tube, wherein the source of the first MOS tube is connected to the source of the second MOS tube, and the gate of the first MOS tube is connected to the drain of the first MOS tube and the gate of the second MOS tube respectively; a plurality of first switches, one end of each of the first switches being connected to a side of a first resistor corresponding to the first switch close to the drain of the second MOS transistor, and the first switch being used to control the first resistor to be connected to the frequency jitter circuit; An operational amplifier, wherein the non-inverting input terminal of the operational amplifier is used to receive the feedback voltage, and the inverting input terminal of the operational amplifier is connected to the output terminal of the operational amplifier; a second resistor, one end of which is connected to the inverting input end of the operational amplifier and the drain of the first MOS tube respectively, and the output end of the operational amplifier is grounded via the second resistor, and the other end of the second resistor is grounded; a fourth resistor, the fourth resistor being connected in series with the plurality of first resistors, and one end of the fourth resistor being grounded; An output port, the other end of the first switch is connected to the output port, and the output port is used to output the reference voltage.

10. The switching power supply system according to claim 8, characterized in that: Also includes: A line voltage detection circuit, wherein the first input end of the frequency jitter circuit is connected to the output end of the line voltage detection circuit, and the line voltage detection circuit is used to receive an input AC voltage.

11. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, the control method of the switching power supply system according to any one of claims 1 to 6 is implemented.

12. A chip, comprising a processor and a communication interface, wherein the communication interface is coupled to the processor, characterized in that: The processor is used to run a program or an instruction, and when the processor executes the program or the instruction, the control method of the switching power supply system according to any one of claims 1 to 6 is implemented.

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