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

Abstract

The present application discloses a control method for a switching power supply system and a switching power supply system, belonging to the technical field of switching power supplies. The control method of the switching power supply system comprises: when the power tube in the switching power supply system is in the off state, obtaining the feedback voltage, target voltage threshold and at least one valley signal corresponding to the switching power supply system in the target switching cycle; the target switching cycle is determined based on the feedback voltage; based on the voltage interval in which the feedback voltage is located, determining the off time corresponding to the power tube; based on the off time, feedback voltage, target voltage threshold and at least one valley signal, controlling the power tube to conduct at the valley corresponding to the target valley signal in at least one valley signal. The control method of the switching power supply system of the present application avoids the problem of the power tube switching back and forth between adjacent valleys or even multiple valleys due to changes in input voltage or load, and improves the overall efficiency of the switching power supply system.

Description

Technical Field

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

[0002] In the field of switching power supplies, the operating voltage of a flyback switching power supply is relatively high, and the parasitic capacitance of the primary power tube is relatively large. It is necessary to lock the valley conduction position of the power tube to reduce switching losses. In the related art, there is a method of valley locking based on switching frequency. However, when the input voltage changes greatly, this method will cause the power tube to switch back and forth between adjacent valleys or even multiple valleys, thereby causing switching frequency disorder, increased output voltage ripple, and audio noise. The overall efficiency of the switching power supply system is low. Summary of the invention

[0003] The present application aims to solve at least one of the technical problems existing in the related art. To this end, the present application proposes a control method of a switching power supply system and a switching power supply system, which avoids the problem of power tubes switching back and forth between adjacent valleys or even multiple valleys due to changes in input voltage or load, thereby avoiding the problems of switching frequency disorder and increased output voltage ripple, and does not generate audio noise, thereby improving the overall efficiency of the switching power supply system.

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

[0005] When the power tube in the switching power supply system is in the off state, a feedback voltage, a target voltage threshold and at least one valley bottom signal corresponding to the switching power supply system in a target switching cycle are obtained; the valley bottom signal is used to characterize that the waveform resonance of the resonant voltage reaches the valley bottom, and the target switching cycle is determined based on the feedback voltage;

[0006] Based on the voltage interval of the feedback voltage, determining the turn-off time corresponding to the power tube; there is a corresponding relationship between the candidate feedback voltage in the voltage interval and the candidate turn-off time, and the corresponding relationship is a functional relationship;

[0007] Based on the turn-off time, the feedback voltage, the target voltage threshold and the at least one valley signal, the power tube is controlled to be turned on at a valley corresponding to a target valley signal in the at least one valley signal.

[0008] According to the control method of the switching power supply system provided in the embodiment of the present application, different turn-off times are adaptively generated by the size of the feedback voltage, and then based on the turn-off time, the feedback voltage, the target voltage threshold and at least one valley signal, it is determined at which valley the power tube is turned on in at least one valley signal, so that the power tube can be turned on at the corresponding valley position, and the valley locking effect is better, avoiding the problem of the power tube switching back and forth between adjacent valleys or even multiple valleys due to changes in input voltage or load, thereby avoiding the problems of switching frequency disorder and increased output voltage ripple, and no audio noise is generated, thereby improving the overall efficiency of the switching power supply system.

[0009] In a control method for a switching power supply system according to an embodiment of the present application, before determining the turn-off time corresponding to the power tube based on the voltage interval of the feedback voltage, the method further includes:

[0010] Based on the target voltage threshold, a plurality of voltage intervals are obtained; the target voltage threshold comprises a target upper limit value, a first voltage threshold value, a second voltage threshold value and a target lower limit value arranged in sequence;

[0011] The corresponding relationship between the candidate feedback voltage and the candidate turn-off time in each of the voltage intervals is established; the corresponding relationship is used to characterize the relationship between the candidate turn-off time and the change of the candidate feedback voltage, and the corresponding relationship includes a constant function or an inverse proportional function.

[0012] In a control method for a switching power supply system according to an embodiment of the present application, establishing the corresponding relationship between the candidate feedback voltage and the candidate turn-off time in each voltage interval includes:

[0013] In the case where the lower limit value of the voltage interval is not less than the target upper limit value, the corresponding relationship is determined as a first linear function; the first linear function is a constant function, and an output value of the first linear function is a minimum off time;

[0014] When the upper limit value of the voltage interval is less than the target upper limit value, and the lower limit value of the voltage interval is greater than the first voltage threshold value, the corresponding relationship is determined as a second linear function; the second linear function is an inverse proportional function, the minimum output value of the second linear function within the voltage interval is the minimum off time, and the maximum output value of the second linear function within the voltage interval is the first off time;

[0015] When the upper limit value of the voltage interval is less than the first voltage threshold value, and the lower limit value of the voltage interval is greater than the second voltage threshold value, the corresponding relationship is determined as a third linear function; the third linear function is an inverse proportional function, the minimum output value of the third linear function within the voltage interval is the first turn-off time, and the maximum output value of the third linear function within the voltage interval is the second turn-off time;

[0016] When the upper limit value of the voltage interval is less than the second voltage threshold value, and the lower limit value of the voltage interval is greater than the target lower limit value, the corresponding relationship is determined as a fourth linear function; the fourth linear function is an inverse proportional function, the minimum output value of the fourth linear function within the voltage interval is the second off time, and the maximum output value of the fourth linear function within the voltage interval is the maximum off time;

[0017] When the upper limit value of the voltage interval is less than the target lower limit value, the corresponding relationship is determined as a fifth linear function; the fifth linear function is a constant function, and an output value of the fifth linear function is the maximum off-time.

[0018] A control method for a switching power supply system according to an embodiment of the present application, wherein based on the off time, the feedback voltage, the target voltage threshold and the at least one valley signal, the power tube is controlled to be turned on at a valley corresponding to a target valley signal in the at least one valley signal, including:

[0019] Acquire a turn-off time signal corresponding to the power tube based on the turn-off moment of the power tube within the target switching cycle, the turn-off time, the feedback voltage, and the target voltage threshold;

[0020] When the turn-off time signal coincides with a first valley signal among the at least one valley signal, the power tube is controlled to be turned on at the valley corresponding to the target valley signal; the first valley signal is a valley signal before the target valley signal.

[0021] A control method for a switching power supply system according to an embodiment of the present application, wherein the switching power supply system includes a target capacitor, and obtaining a turn-off time signal corresponding to the power tube based on the turn-off moment of the power tube within the target switching cycle, the turn-off time, the feedback voltage, and the target voltage threshold, comprises:

[0022] Based on the shut-off moment and the shut-off time, determining a time to generate the shut-off time signal;

[0023] Based on the feedback voltage, the target voltage threshold and the capacitor voltage corresponding to the target capacitance, the shutdown time signal is generated at the generation time; the target voltage threshold includes a target upper limit value, a first voltage threshold, a second voltage threshold and a target lower limit value arranged in sequence.

[0024] A control method for a switching power supply system according to an embodiment of the present application, wherein the switching power supply system comprises a first switch connected in series with the target capacitor, and a second switch, a third switch and a fourth switch respectively connected in parallel with the target capacitor; wherein the method generates the turn-off time signal at the generation time based on the feedback voltage, the target voltage threshold and the capacitor voltage corresponding to the target capacitor, comprising:

[0025] When the capacitor voltage reaches the target upper limit value, the first switch is controlled to be disconnected, and the target capacitor ends the charging mode;

[0026] When the feedback voltage is greater than the first voltage threshold, the second switch and the third switch are controlled to be closed, and the first switch and the fourth switch are controlled to be opened, so that the target capacitor enters a discharge mode, and when the capacitor voltage in the discharge mode is less than the feedback voltage, the turn-off time signal is generated;

[0027] When the feedback voltage is less than the first voltage threshold and greater than the second voltage threshold, the second switch is controlled to be closed, and the first switch, the third switch and the fourth switch are controlled to be opened, so that the target capacitor enters the discharge mode, and when the capacitor voltage in the discharge mode is less than the feedback voltage, the turn-off time signal is generated;

[0028] When the feedback voltage is less than the second voltage threshold, the third switch is controlled to be closed, and the first switch, the second switch and the fourth switch are controlled to be disconnected, and the target capacitor enters the discharge mode. When the capacitor voltage in the discharge mode is less than the feedback voltage, the turn-off time signal is generated.

[0029] A control method for a switching power supply system according to an embodiment of the present application, the switching power supply system includes a second comparator, a third comparator, and a fourth comparator, and the method further includes:

[0030] generating a switch enable signal based on output results of the second comparator, the third comparator and the fourth comparator;

[0031] Based on the switch enable signal, a switch among the first switch, the second switch, the third switch and the fourth switch corresponding to the switch enable signal is controlled to be closed.

[0032] In a second 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:

[0033] Power tube;

[0034] A valley bottom detection module, the valley bottom detection module is used to output at least one valley bottom signal;

[0035] A shut-off time module, wherein an input terminal of the shut-off time module is used to receive a feedback voltage;

[0036] A valley locking module, wherein an input end of the valley locking module is respectively connected to an output end of the valley detection module and an output end of the shutdown time module;

[0037] A driving module, wherein an input end of the driving module is connected to an output end of the valley locking module, and an output end of the driving module is connected to the power tube.

[0038] According to the switching power supply system provided by the embodiment of the present application, different turn-off times are adaptively generated by the size of the feedback voltage, and then based on the turn-off time, the feedback voltage, the target voltage threshold and at least one valley signal, it is determined at which valley the power tube is turned on in at least one valley signal, so that the power tube can be turned on at the corresponding valley position, and the valley locking effect is better, avoiding the problem of the power tube switching back and forth between adjacent valleys or even multiple valleys due to changes in input voltage or load, thereby avoiding the problems of switching frequency disorder and increased output voltage ripple, and no audio noise is generated, thereby improving the overall efficiency of the switching power supply system.

[0039] The switching power supply system of one embodiment of the present application further includes:

[0040] A PWM comparison module, wherein one input end of the PWM comparison module is used to receive the feedback voltage, and another input end of the PWM module is connected to a sampling resistor corresponding to the source end of the power tube;

[0041] A trigger module, one input end of the trigger module is connected to the output end of the valley locking module, another input end of the trigger module is connected to the output end of the PWM comparison module, and the output end of the trigger module is connected to the input end of the driving module.

[0042] In a switching power supply system according to an embodiment of the present application, the shutdown time module includes:

[0043] A clamping circuit; the clamping circuit is used to receive the feedback voltage;

[0044] A first comparator; a non-inverting input terminal of the first comparator is connected to an output terminal of the clamping circuit;

[0045] A first rising edge detection circuit; an input end of the first rising edge detection circuit is connected to an output end of the first comparator, and an output end of the first rising edge detection circuit is connected to the valley locking module;

[0046] A target capacitor; the target capacitor is connected to the inverting input terminal of the first comparator;

[0047] A first switch; the first switch is connected in series with the target capacitor;

[0048] A second switch; the second switch is connected in parallel with the target capacitor;

[0049] A third switch; the third switch is connected in parallel with the target capacitor;

[0050] a fourth switch; the fourth switch is connected in parallel with the target capacitor;

[0051] A switch control circuit; the switch control circuit is connected to the target capacitor, the first switch, the second switch, the third switch and the fourth switch respectively.

[0052] In a switching power supply system according to an embodiment of the present application, the clamping circuit comprises:

[0053] a first operational amplifier; a non-inverting input terminal of the first operational amplifier is used to receive a target upper limit value, and an inverting input terminal of the first operational amplifier is used to receive the feedback voltage;

[0054] NMOS tube; the input end of the NMOS tube is connected to the output end of the first operational amplifier, one output end of the NMOS tube is grounded, and the other output end of the NMOS tube is connected to the inverting input end of the first operational amplifier;

[0055] a second operational amplifier; a non-inverting input terminal of the second operational amplifier is used to receive the target lower limit value, an inverting input terminal of the second operational amplifier is used to receive the feedback voltage, and the inverting input terminal of the second operational amplifier is connected to another output terminal of the NMOS tube;

[0056] PMOS tube; the input end of the PMOS tube is connected to the output end of the second operational amplifier, one output end of the PMOS tube is connected to the power supply, and the other output end of the PMOS tube is connected to the inverting input end of the second operational amplifier.

[0057] In a switching power supply system according to an embodiment of the present application, the switch control circuit includes:

[0058] A second comparator; a non-inverting input terminal of the second comparator is used to receive a target upper limit value, and an inverting input terminal of the second comparator is used to receive a capacitance voltage of the target capacitance;

[0059] A third comparator; the non-inverting input terminal of the third comparator is used to receive the first voltage threshold, and the inverting input terminal of the third comparator is used to receive the feedback voltage;

[0060] A fourth comparator; a non-inverting input terminal of the fourth comparator is used to receive the feedback voltage, and an inverting input terminal of the fourth comparator is used to receive a second voltage threshold;

[0061] A first falling edge detection circuit; the first falling edge detection circuit is connected to the output end of the second comparator;

[0062] A second rising edge detection circuit; the second rising edge detection circuit is used to detect the rising edge of the driving signal;

[0063] The second falling edge detection circuit is used to detect the falling edge of the driving signal.

[0064] In a third aspect, the present application provides a control device for a switching power supply system, the device comprising:

[0065] A first processing module is used to obtain, when the power tube in the switching power supply system is in an off state, a feedback voltage, a target voltage threshold and at least one valley bottom signal corresponding to the switching power supply system within a target switching cycle; the valley bottom signal is used to indicate that the waveform resonance of the resonant voltage reaches the valley bottom, and the target switching cycle is determined based on the feedback voltage;

[0066] A second processing module is used to determine the turn-off time corresponding to the power tube based on the voltage interval of the feedback voltage; there is a corresponding relationship between the candidate feedback voltage and the candidate turn-off time in the voltage interval, and the corresponding relationship is a functional relationship;

[0067] The third processing module is used to control the power tube to be turned on at the valley corresponding to the target valley signal in the at least one valley signal based on the turn-off time, the feedback voltage, the target voltage threshold and the at least one valley signal.

[0068] According to the control device of the switching power supply system provided in the embodiment of the present application, different turn-off times are adaptively generated by the size of the feedback voltage, and then based on the turn-off time, the feedback voltage, the target voltage threshold and at least one valley signal, it is determined at which valley the power tube is turned on in at least one valley signal, so that the power tube can be turned on at the corresponding valley position, and the valley locking effect is better, avoiding the problem of the power tube switching back and forth between adjacent valleys or even multiple valleys due to changes in input voltage or load, thereby avoiding the problems of switching frequency disorder and increased output voltage ripple, and no audio noise is generated, thereby improving the overall efficiency of the switching power supply system.

[0069] In a fourth aspect, the present application provides an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the control method of the switching power supply system as described in the first aspect above is implemented.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] The above one or more technical solutions in the embodiments of the present application have at least one of the following technical effects:

[0074] Different turn-off times are adaptively generated by the size of the feedback voltage, and then based on the turn-off time, feedback voltage, target voltage threshold and at least one valley signal, it is determined at which valley the power tube is turned on in at least one valley signal, so that the power tube can be turned on at the corresponding valley position. The valley locking effect is better, and the problem of the power tube switching back and forth between adjacent valleys or even multiple valleys due to changes in input voltage or load is avoided, thereby avoiding the problems of switching frequency disorder and increased output voltage ripple, and no audio noise is generated, thereby improving the overall efficiency of the switching power supply system.

[0075] Furthermore, the voltage range of the feedback voltage is determined by the magnitude relationship between the feedback voltage and the target voltage threshold, so that when the feedback voltage is different, the turn-off time is adaptively set based on different corresponding relationships, and the number of valleys to be turned on is determined based on the turn-off time, which can better match the primary peak current and the switching frequency to obtain better dynamic characteristics, so that in actual applications, the power tube can be turned on at the corresponding valley position, which improves the accuracy of locking the valley and solves the problem of the power tube switching back and forth between adjacent valleys or even multiple valleys due to changes in input voltage or load.

[0076] Furthermore, through different feedback voltage sizes, a corresponding switch enable signal is generated after passing through a logic circuit to control the corresponding switch to close, thereby generating a turn-off time signal. The valley conduction position of the power tube can be determined based on the turn-off time signal and at least one valley signal, thereby avoiding the problem of the power tube switching back and forth between adjacent valleys or even multiple valleys due to changes in input voltage or load, and no audio noise is generated, and the overall efficiency of the switching power supply system is improved.

[0077] 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

[0078] 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:

[0079] Figure 1 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;

[0080] Figure 2 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;

[0081] Figure 3 This is one of the structural schematic diagrams of the switching power supply system provided in the embodiment of the present application;

[0082] Figure 4 This is the second structural schematic diagram of the switching power supply system provided in the embodiment of the present application;

[0083] Figure 5 This is the third structural diagram of the switching power supply system provided in the embodiment of the present application;

[0084] Figure 6 This is the fourth structural diagram of the switching power supply system provided in the embodiment of the present application;

[0085] Figure 7This is the fifth structural diagram of the switching power supply system provided in the embodiment of the present application;

[0086] 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;

[0087] Fig. 9 This is the second flow chart of the control method of the switching power supply system provided in the embodiment of the present application;

[0088] Fig.10 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;

[0089] Fig.11 It is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application.

[0090] Reference numerals:

[0091] Power tube Q1; rectifier tube Q2; first current source I1; second current source I2; third current source I3;

[0092] A first switch SW1; a second switch SW2; a third switch SW3; a fourth switch SW4; a target capacitor CAP;

[0093] Primary winding Np; auxiliary winding Na; secondary winding Ns; first sampling resistor R CS ; The second sampling resistor R1;

[0094] A third sampling resistor R2; a primary side control circuit 110; a secondary side control circuit 120; a feedback loop 130;

[0095] Valley detection module 140; Valley locking module 150; Trigger module 160; Drive module 170;

[0096] Turn-off time module 180; PWM comparison module 190; clamping circuit 200; switch control circuit 210;

[0097] A first rising edge detection circuit 220; a first operational amplifier op1; a second operational amplifier op2;

[0098] First falling edge detection circuit 230; second falling edge detection circuit 240; second rising edge detection circuit 250

[0099] A first comparator 260 ; a second comparator 270 ; a third comparator 280 ; and a fourth comparator 290 . DETAILED DESCRIPTION

[0100] 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.

[0101] 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.

[0102] 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.

[0103] 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.

[0104] The terminal includes, but is not limited to, a portable communication device such as a mobile phone or tablet computer with a touch-sensitive surface (e.g., a touch screen display and / or a touch pad). It should also be understood that in some embodiments, the terminal may not be a portable communication device, but a desktop computer with a touch-sensitive surface (e.g., a touch screen display and / or a touch pad).

[0105] In the following various embodiments, a terminal including a display and a touch-sensitive surface is described. However, it should be understood that the terminal may include one or more other physical user interface devices such as a physical keyboard, a mouse and a joystick.

[0106] The control method of the switching power supply system provided in the embodiment of the present application, the execution subject of the control method of the switching power supply system may be the switching power supply system, or may be an electronic device connected to the switching power supply system in communication, or may be a functional module or functional entity in the switching power supply system or the electronic device that can implement the control method of the switching power supply 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 supply system provided in the embodiment of the present application is described below by taking the switching power supply system as an execution subject as an example.

[0107] like Figure 1 As shown, the control method of the switching power supply system includes: step S1, step S2 and step S3.

[0108] It should be noted that the control method of the switching power supply system can be applied to a switching power supply system.

[0109] The switching power supply system may be a flyback switching power supply.

[0110] A switching power supply is a high-frequency electric energy conversion device and a type of power supply.

[0111] Switching power supplies are used to convert a voltage level into the voltage or current required by the user through different forms of architecture.

[0112] Switching power supplies can be used in areas such as fast charging, adapters and chargers.

[0113] In practical applications, in order to reduce switching losses and improve conversion efficiency, the switching power supply system can adopt a quasi-resonant (QR) control method.

[0114] Step S1: when the power tube in the switching power supply system is in the off state, obtaining a feedback voltage, a target voltage threshold and at least one valley signal corresponding to the switching power supply system in a target switching cycle.

[0115] In this step, the switching power supply system includes a power tube.

[0116] The power tube includes a gate, a source and a drain.

[0117] The working state of the power tube includes on or off.

[0118] In the actual implementation process, the working state of the power tube can be controlled based on the driving signal.

[0119] For example, when the driving signal changes from a high level to a low level, the power tube is controlled to be turned off; when the driving signal changes from a low level to a high level, the power tube is controlled to be turned on.

[0120] A switching cycle may include a turn-on time and a demagnetization time.

[0121] The length of the target switching period can be determined based on the feedback voltage.

[0122] The target switching cycle is a complete switching cycle in the switching power supply system, including the turn-on and turn-off of the power tube.

[0123] like Figure 2As shown, when the feedback voltage decreases, the on-time and demagnetization time will also decrease, and the switching period will decrease; when the feedback voltage increases, the on-time and demagnetization time will also increase, and the switching period will increase.

[0124] When the switching period is reduced, the switching frequency will increase; when the switching period is increased, the switching frequency will decrease.

[0125] The feedback voltage is the voltage fed back to the primary circuit by the optocoupler.

[0126] 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.

[0127] By sensing the feedback voltage, load changes can be detected.

[0128] When the power tube is turned off, the feedback voltage can be considered unchanged within a switching cycle.

[0129] The target voltage threshold is a preset expected value, and the target voltage threshold can be used to measure the magnitude of the feedback voltage.

[0130] The valley signal is used to characterize that the waveform resonance of the resonant voltage reaches the valley bottom, that is, the position where the valley signal appears can be used to characterize the position where the resonance valley bottom is located.

[0131] By obtaining at least one valley bottom signal, it can be used to determine the next turn-on position of the power tube, so as to improve power efficiency and reduce loss.

[0132] Step S2: determining the turn-off time corresponding to the power tube based on the voltage interval of the feedback voltage.

[0133] In this step, based on the turn-off time, a turn-off time signal may be generated within a target switching period.

[0134] In the actual implementation process, the power tube can be controlled to be turned on at the target valley bottom position based on the turn-off time signal.

[0135] The off time is the duration from the turn-off time of the power tube to the generation time of the turn-off time signal within the target switching cycle.

[0136] When the feedback voltage is different, the turn-off time is also different.

[0137] For example, when the feedback voltage is larger, the turn-off time is shorter; and when the feedback voltage is smaller, the turn-off time is longer.

[0138] When the turn-off time is different, the conduction position of the power tube is also different.

[0139] For example, when the turn-off time is short, the power tube is turned on at the front valley bottom; when the turn-off time is long, the power tube is turned on at the back valley bottom.

[0140] By judging the voltage interval of the feedback voltage, the turn-off time can be determined.

[0141] There is a corresponding relationship between the candidate feedback voltages and the candidate turn-off times within the voltage interval.

[0142] The corresponding relationship is used to characterize the relationship between the candidate off-time and the candidate feedback voltage.

[0143] The candidate feedback voltage is any discrete value within the voltage range and can be obtained based on previous sampling. For example, the candidate feedback voltage can be 1.5V, 2V or any other voltage value.

[0144] The candidate off-time may be 7 μs, 10 μs or any other value, and may be user-defined, and is not limited in this application.

[0145] The corresponding relationship may be a functional relationship between the candidate turn-off time and the candidate feedback voltage.

[0146] The corresponding relationship may include a constant function or an inverse proportional function.

[0147] When the candidate feedback voltages are different, the corresponding relationship between the candidate feedback voltages and the candidate turn-off time is also different.

[0148] In some embodiments, before step S2, the method may further include:

[0149] Based on the target voltage threshold, a plurality of voltage intervals are obtained;

[0150] A corresponding relationship between candidate feedback voltages and candidate turn-off times in each voltage interval is established.

[0151] In this embodiment, the target voltage threshold includes a target upper limit value, a first voltage threshold value, a second voltage threshold value, and a target lower limit value arranged in sequence.

[0152] The value of each threshold can be customized by the user and is not limited in this application.

[0153] The voltage interval can be determined based on the target voltage threshold. For example, when the target upper limit value is 2.4V, the first voltage threshold is 1.8V, the second voltage threshold is 1.2V, and the target lower limit value is 0.6V, the resulting voltage interval can include 2.4V~+∞, 1.8V~2.4V, 1.2V~1.8V, 0.6V~1.2V and 0V~0.6V.

[0154] In the actual implementation process, a set of candidate turn-off times and corresponding candidate feedback voltages can be obtained based on experiments or simulations, and then a function can be fitted based on methods such as linear regression to characterize the corresponding relationship between the two.

[0155] For example, the candidate turn-off time corresponding to the first voltage threshold (1.8V) is 7μs, and the candidate turn-off time corresponding to the second voltage threshold (1.2V) is 21μs. Based on the set slope, a linear function relationship between the candidate feedback voltage and the candidate turn-off time in the voltage range (1.2V~1.8V) can be obtained.

[0156] In some embodiments, after the feedback voltage is actually measured, the voltage interval in which the feedback voltage is located can be determined, and then based on the correspondence between the candidate feedback voltages and the candidate turn-off times within the voltage interval, the candidate turn-off time corresponding to the feedback voltage can be determined as the turn-off time.

[0157] Combine the following Figure 8 , several methods for determining the corresponding relationship between the candidate feedback voltage and the candidate turn-off time are specifically described.

[0158] 1. The lower limit of the voltage range is not less than the target upper limit

[0159] In some embodiments, establishing a correspondence between candidate feedback voltages and candidate turn-off times in each voltage interval may include:

[0160] When the lower limit value of the voltage interval is not less than the target upper limit value, the corresponding relationship is determined as a first linear function.

[0161] In this embodiment, the target upper limit value is V FB_max The target upper limit value may be 2.4V, or may be other values, which may be customized by the user and is not limited in this application.

[0162] The lower limit value of the voltage interval is not less than the target upper limit value, that is, the candidate feedback voltage within the voltage interval is not less than the target upper limit value, and the load is fully loaded or overloaded.

[0163] The load can be regulated based on the primary peak current.

[0164] The first linear function is a constant function.

[0165] The output value of the first linear function is the minimum off time.

[0166] The minimum off time is T off_min The minimum off time can be 3 μs, or can be other values, which can be customized by the user and is not limited in this application.

[0167] In the actual implementation process, when the lower limit value of the voltage range in which the feedback voltage is located is not less than the target upper limit value (2.4V), that is, when the load is fully loaded or overloaded, the turn-off time corresponding to the feedback voltage can be determined to be 3μs, so that the power tube operates at the front valley bottom.

[0168] For example, when the input AC voltage is low, the power tube can operate at the first valley bottom based on the minimum off time; when the input AC voltage is high, the power tube can operate at the third valley bottom based on the minimum off time.

[0169] In the present application, by determining the corresponding relationship as the minimum off-time when the lower limit value of the voltage interval is not less than the target upper limit value, when the feedback voltage is not less than the target upper limit value, the power tube is turned on based on the minimum off-time, so that the power tube can operate at the front valley bottom, thereby improving the working efficiency of the switching power supply.

[0170] 2. The upper limit of the voltage interval is less than the target upper limit, and the lower limit of the voltage interval is greater than the first voltage threshold

[0171] In some embodiments, establishing a correspondence between candidate feedback voltages and candidate turn-off times in each voltage interval may include:

[0172] When the upper limit value of the voltage interval is smaller than the target upper limit value, and the lower limit value of the voltage interval is larger than the first voltage threshold value, the corresponding relationship is determined as a second linear function.

[0173] In this embodiment, the first voltage threshold is V FB_mid_H The first voltage threshold is less than the target upper limit value. For example, the first voltage threshold may be 1.8V, or may be other values, which may be customized by the user and is not limited in this application.

[0174] The upper limit value of the voltage interval is less than the target upper limit value, and the lower limit value of the voltage interval is greater than the first voltage threshold, that is, the candidate feedback voltage in the voltage interval is less than the target upper limit value and greater than the first voltage threshold, and the load of the switching power supply system is overloaded.

[0175] The second linear function is an inverse proportional function, that is, the candidate off-time decreases as the candidate feedback voltage increases.

[0176] The independent variable of the second linear function is the candidate feedback voltage, and the variable of the second linear function is the candidate off-time.

[0177] The minimum output value of the second linear function within the voltage range is the minimum off time T corresponding to the target upper limit value. off_min .

[0178] The maximum output value of the second linear function within the voltage interval is the first off time T corresponding to the first voltage threshold off_mid_L .

[0179] The first off-time may be 7 μs, or may be other values, which may be customized by the user and is not limited in this application.

[0180] The variation slope of the second linear function is greater than that of the first linear function.

[0181] The turn-off time corresponding to the feedback voltage between the first voltage threshold and the target upper limit value is greater than the turn-off time corresponding to the feedback voltage above the target upper limit value. When the turn-off time increases, the number of valleys increases, the switching frequency decreases, and the output power decreases.

[0182] In the actual implementation process, the target upper limit value can be set to 2.4V, and the first voltage threshold can be set to 1.8V. When the feedback voltage is 2.1V, based on the second linear function, it can be obtained that the turn-off time corresponding to the feedback voltage is 5μs.

[0183] In the present application, when the load is under heavy load, the turn-off time is determined based on a second linear function with a smaller change slope, so that the conduction valley of the power tube will be changed only when the feedback voltage changes greatly, thereby widening the valley locking interval when the load is under heavy load, and the valley locking is more stable.

[0184] 3. The upper limit of the voltage interval is less than the first voltage threshold, and the lower limit of the voltage interval is greater than the second voltage threshold

[0185] In some embodiments, establishing a correspondence between candidate feedback voltages and candidate turn-off times in each voltage interval may include:

[0186] When the upper limit value of the voltage interval is less than the first voltage threshold value, and the lower limit value of the voltage interval is greater than the second voltage threshold value, the corresponding relationship is determined as a third linear function.

[0187] In this embodiment, the second voltage threshold is V FB_mid_L The second voltage threshold is less than the first voltage threshold. For example, the second voltage threshold may be 1.2V, or may be other values, which may be user-defined and is not limited in this application.

[0188] The upper limit of the voltage interval is less than the first voltage threshold, and the lower limit of the voltage interval is greater than the second voltage threshold, that is, the candidate feedback voltage in the voltage interval is less than the first voltage threshold and greater than the second voltage threshold, that is, the load is at medium load.

[0189] The third linear function is an inverse proportional function, that is, the candidate off-time decreases as the candidate feedback voltage increases.

[0190] The independent variable of the third linear function is the candidate feedback voltage, and the variable of the third linear function is the candidate turn-off time.

[0191] The minimum output value of the third linear function within the voltage interval is the first off time T corresponding to the first voltage threshold off_mid_L .

[0192] The maximum output value of the third linear function within the voltage interval is the second off time T corresponding to the second voltage threshold off_mid_H .

[0193] The second off-time may be 21 μs, or may be other values, which may be customized by the user and is not limited in this application.

[0194] The change slope of the third linear function is greater than that of the second linear function.

[0195] The turn-off time corresponding to the feedback voltage between the second voltage threshold and the first voltage threshold is greater than the turn-off time corresponding to the feedback voltage between the first voltage threshold and the target upper limit value, that is, when the load is reduced from heavy load to medium load, the turn-off time corresponding to the feedback voltage will increase.

[0196] When the load is at medium load, the load can be adjusted based on the switching frequency.

[0197] In actual implementation, the first voltage threshold may be set to 1.8V, and the second voltage threshold may be set to 1.2V. When the feedback voltage is 1.5V, based on the third linear function, the turn-off time corresponding to the feedback voltage may be 14 μs.

[0198] 4. The upper limit of the voltage range is less than the second voltage threshold, and the lower limit of the voltage range is greater than the target lower limit

[0199] In some embodiments, establishing a correspondence between candidate feedback voltages and candidate turn-off times in each voltage interval may include:

[0200] When the upper limit value of the voltage interval is less than the second voltage threshold value, and the lower limit value of the voltage interval is greater than the target lower limit value, the corresponding relationship is determined as a fourth linear function.

[0201] In this embodiment, the target lower limit value is V FB_min The target lower limit value may be 0.6V, or may be other values, which may be customized by the user and is not limited in this application.

[0202] The upper limit of the voltage interval is less than the second voltage threshold, and the lower limit of the voltage interval is greater than the target lower limit, that is, the candidate feedback voltage in the voltage interval is less than the second voltage threshold and greater than the target lower limit, that is, the load is lightly loaded.

[0203] The fourth linear function is an inverse proportional function, that is, the off time decreases as the feedback voltage increases.

[0204] The independent variable of the fourth linear function is the candidate feedback voltage, and the variable of the fourth linear function is the candidate turn-off time.

[0205] The minimum output value of the fourth linear function within the voltage interval is the second off time T corresponding to the second voltage threshold off_mid_H .

[0206] The maximum output value of the fourth linear function within the voltage range is the maximum off time T corresponding to the target lower limit value. off_max .

[0207] The maximum off time may be 42 μs, or may be other values, which may be customized by the user and is not limited in this application.

[0208] The change slope of the fourth linear function is greater than that of the third linear function.

[0209] When the load is light, the power tube may operate after the 6th or 7th valley and no longer perform valley locking.

[0210] 5. The upper limit of the voltage range is less than the target lower limit

[0211] In some embodiments, establishing a correspondence between candidate feedback voltages and candidate turn-off times in each voltage interval may include:

[0212] When the upper limit value of the voltage interval is less than the target lower limit value, the corresponding relationship is determined as a fifth linear function.

[0213] In this embodiment, when the upper limit value of the voltage interval is less than the target lower limit value, that is, when the candidate feedback voltage in the voltage interval is less than the target lower limit value, it can be considered that the load is unloaded.

[0214] The fifth linear function is a constant function.

[0215] The output value of the fifth linear function is the maximum off time T off_max .

[0216] In the actual implementation process, when the load is in the no-load state, the feedback voltage is less than 0.6V, and the turn-off time can be determined to be 42μs, at which time the switching frequency is the lowest.

[0217] According to the control method of the switching power supply system provided in the embodiment of the present application, the voltage range of the feedback voltage is determined by the size relationship between the feedback voltage and the target voltage threshold, so that when the feedback voltage is different, the shutdown time is adaptively set based on different corresponding relationships, and the number of valleys to be turned on is determined based on the shutdown time, which can better match the primary peak current and the switching frequency to obtain better dynamic characteristics, so that in actual application, the power tube can be turned on at the corresponding valley position, which improves the accuracy of locking the valley, and solves the problem of the power tube switching back and forth between adjacent valleys or even multiple valleys due to changes in input voltage or load.

[0218] Step S3: Based on the turn-off time, the feedback voltage, the target voltage threshold and at least one valley signal, the power tube is controlled to be turned on at a valley corresponding to the target valley signal in the at least one valley signal.

[0219] In this step, the target valley bottom signal is any valley bottom signal among the at least one valley bottom signal.

[0220] After the off-time is determined, an off-time signal may be generated.

[0221] Based on the turn-off time and the turn-off moment of the power tube in the target switching cycle, the generation moment of the turn-off time signal can be determined.

[0222] The turn-off time of the power tube is the time when the power tube switches from the on state to the off state within the target switching cycle.

[0223] The generation time of the off-time signal is the time when the off-time signal changes from a low level to a high level.

[0224] Based on the feedback voltage and the target voltage threshold, an off-time signal may be generated.

[0225] Based on the position of the off-time signal relative to at least one valley signal, the number of turn-on valleys can be determined, and the power tube can be controlled to be turned on at the valley corresponding to the target valley signal.

[0226] According to the control method of the switching power supply system provided in the embodiment of the present application, different turn-off times are adaptively generated by the size of the feedback voltage, and then based on the turn-off time, the feedback voltage, the target voltage threshold and at least one valley signal, it is determined at which valley the power tube is turned on in at least one valley signal, so that the power tube can be turned on at the corresponding valley position, and the valley locking effect is better, avoiding the problem of the power tube switching back and forth between adjacent valleys or even multiple valleys due to changes in input voltage or load, thereby avoiding the problems of switching frequency disorder and increased output voltage ripple, and no audio noise is generated, thereby improving the overall efficiency of the switching power supply system.

[0227] In some embodiments, step S3 may include:

[0228] Based on the turn-off moment, turn-off time, feedback voltage and target voltage threshold of the power tube within the target switching cycle, a turn-off time signal corresponding to the power tube is obtained;

[0229] In the case where the off-time signal coincides with a first valley signal of at least one valley signal, the power tube is controlled to be turned on at the valley corresponding to the target valley signal.

[0230] In this embodiment, the target switching cycle includes turning off and on the power tube.

[0231] The off time signal can be used to control the conduction of the power tube.

[0232] There is at least one valley signal within the target switching cycle.

[0233] The first valley bottom signal is a valley bottom signal before the target valley bottom signal.

[0234] The off-time signal is a pulse signal.

[0235] In the case where the off-time signal is detected at the bottom of the first bottom-of-valley signal, it can be determined that the off-time signal coincides with the first bottom-of-valley signal.

[0236] In some embodiments, controlling the power tube to be turned on at the valley corresponding to the target valley signal may include:

[0237] Acquire a valley conduction signal at the valley bottom corresponding to the target valley bottom signal;

[0238] Based on the valley conduction signal, the power tube is controlled to be turned on.

[0239] In this embodiment, the valley conduction signal is used to control the driving voltage to be at a high level, thereby driving the power tube to be turned on based on the driving voltage.

[0240] In the actual implementation process, the off-time signal V off The position of the relative valley signal determines the number of valleys to be turned on. For example, the turn-off time signal V is detected at the nth valley (i.e., the valley corresponding to the first valley signal). off In this case, a valley turn-on signal qr_on can be output at the n+1th valley (i.e., the valley corresponding to the target valley signal) to control the power tube to turn on at the n+1th valley, and the current valley number is latched and recorded as n+1.

[0241] In some embodiments, the switching power supply system includes a target capacitor, and obtaining a turn-off time signal corresponding to the power tube based on the turn-off moment, turn-off time, feedback voltage, and target voltage threshold of the power tube within the target switching cycle may include:

[0242] Determine a generation time of a turn-off time signal based on the turn-off moment and the turn-off time;

[0243] An off-time signal is generated at a generation time based on the feedback voltage, the target voltage threshold, and a capacitor voltage corresponding to the target capacitance.

[0244] In this embodiment, if Figure 5 As shown, the switching power supply system includes a target capacitor CAP.

[0245] The switching power supply system further includes a first switch SW1 , a second switch SW2 , a third switch SW3 and a fourth switch SW4 .

[0246] The target capacitor is connected in series with the first current source I1 through the first switch.

[0247] The second switch is connected in series with the second current source I2 and in parallel with the target capacitor.

[0248] The third switch is connected in series with the third current source I3 and in parallel with the target capacitor.

[0249] The target capacitor is connected in parallel with the fourth switch.

[0250] Based on the turn-off time T1 and the turn-off time T off , the generation time of the turn-off time signal can be determined as T1+T off .

[0251] The target voltage threshold includes a target upper limit value, a first voltage threshold value, a second voltage threshold value, and a target lower limit value which are arranged in sequence.

[0252] Capacitor voltage V CAP is the voltage across the target capacitor. When the first switch SW1, the second switch SW2, the third switch SW3 and the fourth switch SW4 are in different open and closed states, the current for charging and discharging the target capacitor will change, thereby causing the capacitor voltage to change.

[0253] Based on the feedback voltage, the target voltage threshold, and the capacitor voltage, an off-time signal may be generated at a generation time.

[0254] For example, based on the magnitude relationship between the feedback voltage and the target voltage threshold, a target switch among multiple switches can be controlled to close, thereby obtaining the capacitor voltage when the target switch is closed, and comparing it with the feedback voltage to generate a turn-off time signal.

[0255] In some embodiments, generating a turn-off time signal at a generation time based on the feedback voltage, the target voltage threshold, and the capacitor voltage corresponding to the target capacitance may include:

[0256] When the capacitor voltage reaches the target upper limit value, the first switch is controlled to be disconnected, and the target capacitor ends the charging mode;

[0257] When the feedback voltage is greater than the first voltage threshold, the second switch and the third switch are controlled to be closed, and the first switch and the fourth switch are controlled to be opened, so that the target capacitor enters a discharge mode, and when the capacitor voltage in the discharge mode is less than the feedback voltage, a turn-off time signal is generated;

[0258] When the feedback voltage is less than the first voltage threshold and greater than the second voltage threshold, the second switch is controlled to be closed, and the first switch, the third switch and the fourth switch are controlled to be opened, so that the target capacitor enters the discharge mode, and when the capacitor voltage in the discharge mode is less than the feedback voltage, a turn-off time signal is generated;

[0259] When the feedback voltage is less than the second voltage threshold, the third switch is controlled to close, and the first switch, the second switch and the fourth switch are controlled to open, and the target capacitor enters the discharge mode. When the capacitor voltage in the discharge mode is less than the feedback voltage, a shutdown time signal is generated.

[0260] In this embodiment, if Figure 5 As shown, when the first switch SW1 is closed, the first current source I1 can charge the target capacitor CAP.

[0261] When the second switch SW2 and the third switch SW3 are closed and the first switch SW1 and the fourth switch SW4 are opened, the target capacitor starts to discharge, and the discharge current is I2+I3.

[0262] When the second switch SW2 is closed and the first switch SW1 , the third switch SW3 , and the fourth switch SW4 are opened, the target capacitor starts to discharge, and the discharge current is I2 .

[0263] When the third switch SW3 is closed and the first switch SW1 , the second switch SW2 , and the fourth switch SW4 are opened, the target capacitor starts to discharge, and the discharge current is I3 .

[0264] The discharge current of the second current source I2 is greater than the discharge current of the third current source I3.

[0265] After the capacitor voltage reaches the target upper limit value, the target capacitor is controlled to enter a discharge mode, and the capacitor voltage in the discharge mode is less than the target upper limit value.

[0266] When the capacitor voltage decreases to be less than the feedback voltage, the output of the first comparator may change from a low level to a high level, and a turn-off time signal may be generated after passing through the rising edge detection circuit.

[0267] In the actual implementation process, Figure 5As shown, by controlling the on and off of the switch SWn (where n=1, 2, 3, 4), the current for charging and discharging the target capacitor CAP can be adjusted, thereby adjusting the capacitor voltage V CAP , the capacitor voltage V is determined by the first comparator CAP and feedback voltage V FB The size of the rising edge detection circuit can generate a turn-off time signal V off .

[0268] The non-inverting input terminal of the first comparator is used to receive the voltage V FB_follow The inverting input of the comparator is used to receive the capacitor voltage V CAP , the output end of the comparator is connected to the rising edge detection circuit.

[0269] Feedback voltage V FB After passing through the clamping circuit, the voltage V FB_follow .

[0270] like Figure 6 As shown, the clamping circuit includes a first operational amplifier op1, an NMOS tube, a second operational amplifier op2 and a PMOS tube.

[0271] The clamp circuit can FB_follow Limit to the target upper limit V FB_max and the target lower limit V FB_min between.

[0272] The non-inverting input terminal of the first operational amplifier is used to receive the target upper limit value V FB_max , the inverting input terminal of the first operational amplifier is used to receive the feedback voltage V FB .

[0273] The output terminal of the first operational amplifier is connected to the input terminal of the NMOS tube.

[0274] One output end of the NMOS tube is grounded, and the other output end of the NMOS tube is connected to the inverting input end of the second operational amplifier.

[0275] The non-inverting input terminal of the second operational amplifier is used to receive the target lower limit value V FB_max The inverting input terminal of the second operational amplifier is used to receive the feedback voltage V FB .

[0276] The output end of the second operational amplifier is connected to the input end of the PMOS tube.

[0277] One output end of the PMOS tube is connected to a power source, and the other output end of the PMOS tube is connected to the other output end of the NMOS tube.

[0278] When the feedback voltage is greater than the target upper limit, the clamp circuit outputs a voltage VFB_follow V FB_max .

[0279] When the feedback voltage is less than the target lower limit, the clamp circuit outputs a voltage V FB_follow V FB_min .

[0280] When the feedback voltage is not less than the target lower limit and not greater than the target upper limit, the voltage V output by the clamp circuit is FB_follow V FB .

[0281] In some embodiments, the method may further include:

[0282] generating a switch enable signal based on output results of the second comparator, the third comparator, and the fourth comparator;

[0283] Based on the switch enable signal, a switch corresponding to the switch enable signal among the first switch, the second switch, the third switch and the fourth switch is controlled to be closed.

[0284] In this embodiment, if Figure 7 As shown, the switching power supply system may further include a second comparator, a third comparator and a fourth comparator.

[0285] The non-inverting input terminal of the second comparator is used to receive the target upper limit value V FB_max The inverting input terminal of the second comparator is used to receive the capacitor voltage V CAP .

[0286] The output terminal of the second comparator is connected to the first falling edge detection circuit.

[0287] The non-inverting input terminal of the third comparator is used to receive V FB_mid_H The inverting input terminal of the third comparator is used to receive the feedback voltage V FB .

[0288] The non-inverting input terminal of the fourth comparator is used to receive the feedback voltage V FB , the inverting input of the fourth comparator is used to receive V FB_mid_L .

[0289] The second falling edge detection circuit and the second rising edge detection circuit are used to detect the change of the driving signal DRV.

[0290] The switch enable signals include a first enable signal SW1_EN, a second enable signal SW2_EN, a third enable signal SW3_EN, and a fourth enable signal SW4_EN.

[0291] When the first enable signal is at a high level, the first switch may be controlled to be closed based on the first enable signal.

[0292] When the second enable signal is at a high level, the second switch may be controlled to be closed based on the second enable signal.

[0293] When the third enable signal is at a high level, the third switch may be controlled to be closed based on the third enable signal.

[0294] When the fourth enable signal is at a high level, the fourth switch may be controlled to be closed based on the fourth enable signal.

[0295] In the actual execution process, according to the output results of the second comparator, the third comparator and the fourth comparator and the change of the driving signal, a corresponding switch enable signal SWn_EN can be generated after passing through the logic circuit to control the on and off of the switch corresponding to the enable signal.

[0296] When the driving signal DRV changes from a high level to a low level, the power tube is turned off.

[0297] When the falling edge detection circuit detects the falling edge of the drive signal DRV, the circuit output SW1_EN can be controlled to be high, SW2_EN to be low, SW3_EN to be low, and SW4_EN to be low. Then, the first switch SW1 is turned on, the second switch SW2 is turned off, the third switch SW3 is turned off, and the fourth switch SW4 is turned off. The first current source I1 charges the target capacitor CAP.

[0298] The capacitor voltage V CAP Increase to the target upper limit value V FB_MAX In this case, the output of the second comparator changes from high level to low level. After passing through the falling edge detection circuit and the inverter, the switch control circuit output SW1_EN is low level, the first switch SW1 is disconnected, the first current source I1 finishes charging the target capacitor CAP, and then the first comparator starts working.

[0299] The feedback voltage V FB Greater than the target upper limit V FB_max In the case of , the switch control circuit outputs SW2_EN as a high level, SW3_EN as a high level, to control the second switch SW2 and the third switch SW3 to close, the target capacitor starts to discharge, and the discharge current is I2+I3. At this time, the capacitor voltage is less than the feedback voltage, and the output of the first comparator changes from a low level to a high level. After passing through the rising edge detection circuit, a turn-off time signal V is generated. off .

[0300] The feedback voltage V FB Less than the target upper limit V FB_max and is greater than the first voltage threshold V FB_mid_HIn the case of , the second switch SW2 and the third switch SW3 are closed, the first switch SW1 and the fourth switch SW4 are opened, and the discharge current of the target capacitor CAP is I2+I3, V CAP Gradually decreases until it is lower than the feedback voltage V FB When the output of the first comparator turns high, it generates a turn-off time signal V after passing through the rising edge detection circuit. off .

[0301] The feedback voltage V FB Less than the first voltage threshold V FB_mid_H and is greater than the second voltage threshold V FB_mid_L In the case where the outputs of the third comparator and the fourth comparator are high, the switch control circuit outputs SW2_EN as high and SW3_EN as low, so as to control the second switch SW2 to be closed, the third switch SW3 to be opened, and the first switch SW1 and the fourth switch SW1 to be opened, wherein the discharge current of the second current source I2 is greater than the discharge current of the third current source I3, and the discharge current of the target capacitor CAP is I2, V CAP Gradually decreases until it is lower than the feedback voltage V FB When the output of the first comparator turns high, it generates a turn-off time signal V after passing through the rising edge detection circuit. off .

[0302] The feedback voltage V FB Less than the second voltage threshold V FB_mid_L And greater than the target lower limit V FB_min In the case of , the output of the fourth comparator flips to a low level, the switch control circuit outputs SW2_EN to be low, SW3_EN to be high, the second switch SW2 is disconnected, the third switch SW3 is closed, and the first switch SW1 and the fourth switch SW1 are both disconnected, the discharge current of the target capacitor CAP is I3, V CAP Gradually decreases until it is lower than the feedback voltage V FB When the output of the first comparator turns high, it generates a turn-off time signal V after passing through the rising edge detection circuit. off .

[0303] The feedback voltage V FB Less than the target lower limit V FB_min In the case of , the switch control circuit output SW2_EN is low, SW3_EN is high, the second switch SW2 is open, the third switch SW3 is closed, and the first switch SW1 and the fourth switch SW1 are both in the open state, the discharge current of the target capacitor CAP is I3, and the input signal V FB_follow The minimum value is limited to V FB_min , then at V CAP Below the target lower limit VFB_min In the case of , the output of the first comparator flips to a high level, and after passing through the rising edge detection circuit, a turn-off time signal V is generated. off .

[0304] In the actual execution process, when the drive signal DRV changes from a low level to a high level, the power tube is turned on, the rising edge detection circuit detects the rising edge of the drive signal DRV, and the switch control circuit outputs SW4_EN as high to control the fourth switch SW4 to close, and the voltage on the target capacitor CAP is reset.

[0305] According to the control method of the switching power supply system provided in the embodiment of the present application, through different feedback voltage sizes, a corresponding switch enable signal is generated after passing through a logic circuit to control the corresponding switch to close, thereby generating a turn-off time signal. The valley conduction position of the power tube can be determined based on the turn-off time signal and at least one valley signal, thereby avoiding the problem of the power tube switching back and forth between adjacent valleys or even multiple valleys due to changes in input voltage or load, and no audio noise is generated, and the overall efficiency of the switching power supply system is improved.

[0306] The present application also provides a switching power supply system.

[0307] The switching power supply system may be a flyback switching power supply.

[0308] like Figure 3 As shown, the switching power supply system includes a primary control circuit 110, a feedback loop 130, a secondary control circuit 120, 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, a third sampling resistor R2 and a rectifier tube Q2.

[0309] In this embodiment, the power transistor Q1 includes a source, a drain and a gate.

[0310] 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.

[0311] The gate of the power tube Q1 is connected to the DRV pin of the primary control circuit 110 .

[0312] 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.

[0313] 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 control circuit 110 .

[0314] The voltage on the auxiliary winding Na is in phase with the drain voltage of the power tube Q1.

[0315] 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.

[0316] The connecting point of the second sampling resistor R1 and the third sampling resistor R2 is connected to the ZCD pin of the primary side control circuit 110 .

[0317] The same end of the secondary winding Ns is connected to the drain of the rectifier tube Q2, and the other end of the secondary winding Ns is grounded.

[0318] The gate of the rectifier tube Q2 is connected to the secondary control circuit 120 , the source of the rectifier tube Q2 is connected to the output capacitor Cout, and the other end of the output capacitor Cout is grounded.

[0319] The output voltage Vout is connected to the FB pin of the primary control circuit 110 through the feedback loop 130 .

[0320] The main structure of the primary side control circuit 110 is as follows: Figure 4 As shown, the primary side control circuit 110 includes: a valley detection module 140 , a turn-off time module 180 , a valley locking module 150 and a driving module 170 .

[0321] The valley bottom detection module 140 is configured to output at least one valley bottom signal.

[0322] The output end of the valley bottom detection module 140 is connected to the input end of the valley bottom locking module 150 .

[0323] The input signal of the valley detection module 140 is the auxiliary winding voltage sampling signal ZCD.

[0324] The variation trend of the auxiliary winding voltage sampling signal ZCD waveform is consistent with the variation trend of the drain of the primary power tube Q1, and the ZCD signal can be used for valley detection.

[0325] When the power tube Q1 is turned off, the valley detection module 140 starts to work, converts at least one detected valley signal valley into a counting signal, and latches the counting signal.

[0326] When the counting signal of the current switching cycle is the same as the counting signal of the previous switching cycle, the valley detection module 140 generates a corresponding control signal and sends it to the valley locking module 150 .

[0327] An input terminal of the off-time module 180 is used to receive a feedback voltage.

[0328] The off time module 180 can output the off time T according to the magnitude of the feedback voltage. off And the off time signal V off .

[0329] When the load is heavier, the feedback voltage is larger, the off time is shorter, the corresponding valley number is closer to the front, and the switching frequency is increased.

[0330] When the load is lighter, the feedback voltage is smaller, the shutdown time is longer, the corresponding valley bottom number is later, and the switching frequency is reduced.

[0331] An output terminal of the off-time module 180 is connected to an input terminal of the valley locking module 150 .

[0332] The off-time module 180 outputs an off-time signal to the valley locking module 150 .

[0333] like Figure 5 As shown, in some embodiments, the off time module 180 may include: a clamping circuit 200, a first comparator 260, a first rising edge detection circuit 220, a switch control circuit 210, a target capacitor CAP, a first switch SW1, a second switch SW2, a third switch SW3, a fourth switch SW4, a first current source I1, a second current source I2C and a third current source I3.

[0334] In this embodiment, the input terminal of the clamp circuit 200 is used to receive the feedback voltage V FB , the output terminal of the clamp circuit 200 is used to output the voltage V FB_follow .

[0335] The positive input terminal of the first comparator 260 is connected to the output terminal of the clamp circuit 200, and the negative input terminal of the first comparator 260 is used to receive the capacitor voltage V CAP .

[0336] The input end of the first rising edge detection circuit 220 is connected to the output end of the first comparator 260. The first rising edge detection circuit 220 is used to output a turn-off time signal V off .

[0337] The target capacitance CAP is connected in series with the first switch SW1 and the first current source I1 .

[0338] The second switch SW2 is connected in series with the second current source I2 and in parallel with the target capacitor CAP.

[0339] The third switch SW3 is connected in series with the third current source I3 and is connected in parallel with the target capacitor CAP.

[0340] The target capacitance CAP is connected in parallel to the fourth switch SW4 .

[0341] The switch control circuit 210 is connected to the first switch SW1 , the second switch SW2 , the third switch SW3 , and the fourth switch SW4 , respectively.

[0342] like Figure 6 As shown, in some embodiments, the clamp circuit 200 may include: a first operational amplifier op1, an NMOS transistor, a second operational amplifier op2, and a PMOS transistor.

[0343] In this embodiment, the non-inverting input terminal of the first operational amplifier op1 is used to receive the target upper limit value V FB_max The inverting input terminal of the first operational amplifier op1 is used to receive the feedback voltage V FB .

[0344] The output terminal of the first operational amplifier op1 is connected to the input terminal of the NMOS tube.

[0345] One output end of the NMOS tube is grounded, and the other output end of the NMOS tube is connected to the inverting input end of the first operational amplifier op1.

[0346] The non-inverting input terminal of the second operational amplifier op2 is used to receive the target lower limit value V FB_max The inverting input terminal of the second operational amplifier op2 is used to receive the feedback voltage V FB .

[0347] The inverting input terminal of the second operational amplifier op2 is connected to the other output terminal of the NMOS tube.

[0348] The output end of the second operational amplifier op2 is connected to the input end of the PMOS tube.

[0349] One output end of the PMOS tube is connected to the power supply, and the other output end of the PMOS tube is connected to the inverting input end of the second operational amplifier op2.

[0350] like Figure 7 As shown, in some embodiments, the switch control circuit 210 may include: a second comparator 270 , a third comparator 280 , a fourth comparator 290 , a second rising edge detection circuit 250 , a first falling edge detection circuit 230 and a second falling edge detection circuit 240 .

[0351] In this embodiment, the non-inverting input terminal of the second comparator 270 is used to receive the target upper limit value V FB_max The inverting input terminal of the second comparator 270 is used to receive the capacitor voltage V CAP .

[0352] An output terminal of the second comparator 270 is connected to the first falling edge detection circuit 230 .

[0353] The non-inverting input terminal of the third comparator 280 is used to receive V FB_mid_H The inverting input terminal of the third comparator 280 is used to receive the feedback voltage V FB .

[0354] The non-inverting input terminal of the fourth comparator 290 is used to receive the feedback voltage V FB The inverting input terminal of the fourth comparator 290 is used to receive V FB_mid_L .

[0355] The second falling edge detection circuit 240 and the second rising edge detection circuit 250 are used to detect the change of the driving signal DRV.

[0356] The valley locking module 150 determines the valley conduction position of the power tube Q1 based on the turn-off time signal and at least one valley signal, and outputs a valley conduction signal qr_on to the trigger module 160 to complete the valley locking.

[0357] The input end of the driving module 170 is connected to the output end of the valley locking module 150 , and the output end of the driving module 170 is connected to the power tube Q1 .

[0358] The driving module 170 is used to control the power tube Q1 to be turned on at the valley corresponding to the target valley signal.

[0359] Continue to refer Figure 4 In some embodiments, the switching power supply system may further include: a PWM comparison module 190 and a trigger module 160 .

[0360] In this embodiment, one input terminal of the PWM comparison module 190 is used to receive the feedback voltage, and the other input terminal of the PWM module is connected to the sampling resistor corresponding to the source terminal of the power tube Q1 to receive the primary current peak sampling signal V CS .

[0361] The primary current flows through the sampling resistor on CS to obtain the voltage signal V CS , voltage signal V CS Used to characterize the magnitude of the primary current.

[0362] The output power calculation formula is:

[0363]

[0364] Among them, L p is the primary winding inductance, F SW is the switching frequency, I pk is the primary peak current.

[0365] The PWM comparison module 190 may output a shut-down signal gate_off according to the magnitude of the feedback voltage.

[0366] The heavier the load, the greater the feedback voltage and the greater the on-time T onThe longer it is, the longer the primary winding charging excitation time is, that is, the greater the primary peak current is, increasing the energy provided to the secondary winding.

[0367] When the load is lighter, the feedback voltage is smaller and the on-time T on The shorter it is, the shorter the primary winding charging excitation time is, that is, the smaller the primary peak current is, reducing the energy provided to the secondary winding.

[0368] The trigger module 160 may be a RS trigger.

[0369] The trigger module 160 includes an S terminal, an R terminal and a Q terminal.

[0370] The S terminal of the trigger module 160 is connected to the output terminal of the valley locking module 150 , and the S terminal can be used to receive the valley conduction signal qr_on.

[0371] The R terminal of the trigger module 160 is connected to the output terminal of the PWM comparison module 190 , and the R terminal is used to receive the shutdown signal gate_off.

[0372] The Q terminal of the trigger module 160 is connected to the input terminal of the driving module 170 .

[0373] When the rising edge of the valley conduction signal qr_on is detected at the S terminal, the output terminal Q is set to a high level.

[0374] When the Q-terminal output is at a high level, the driving circuit can control the power tube Q1 to turn on.

[0375] When the R terminal detects the rising edge of the shutdown signal gate_off, the output terminal Q is set to a low level.

[0376] When the Q-terminal output is at a low level, the drive circuit can control the power tube Q1 to turn off.

[0377] Combine the following Fig. 9 As well as the switching power supply system provided in the embodiment of the present application, the execution process of the control method of the switching power supply system provided in the embodiment of the present application is specifically described.

[0378] The valley detection module 140 generates at least one valley signal according to the ZCD voltage waveform, and inputs the at least one valley signal to the valley locking module 150 .

[0379] The off time module 180 is based on the feedback voltage V FB The size generates the corresponding off time T off , and the off time signal V off .

[0380] The valley lock circuit turns off the time signal V offRelative to the position of at least one valley signal, it is determined at which valley the power tube Q1 is turned on.

[0381] The PWM comparison module 190 generates a voltage V FB The size determines the conduction time of the power tube Q1.

[0382] According to the switching power supply system provided by the embodiment of the present application, different turn-off times are adaptively generated by the size of the feedback voltage, and then based on the turn-off time, the feedback voltage, the target voltage threshold and at least one valley signal, it is determined at which valley the power tube Q1 is turned on in at least one valley signal, so that the power tube Q1 can be turned on at the corresponding valley position, and the valley locking effect is better, avoiding the problem of the power tube Q1 switching back and forth between adjacent valleys or even multiple valleys due to changes in the input voltage or load, thereby avoiding the problems of switching frequency disorder and increased output voltage ripple, and no audio noise is generated, thereby improving the overall efficiency of the switching power supply system.

[0383] The control device of the switching power supply system provided in the present application is described below. The control device of the switching power supply system described below and the control method of the switching power supply system described above can be referred to each other.

[0384] 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.

[0385] An embodiment of the present application also provides a control device for a switching power supply system.

[0386] like Fig.10 As shown, the control device of the switching power supply system includes: a first processing module 1010 , a second processing module 1020 and a third processing module 1030 .

[0387] The first processing module 1010 is used to obtain a feedback voltage, a target voltage threshold, and at least one valley bottom signal corresponding to the switching power supply system in a target switching cycle when the power tube in the switching power supply system is in an off state; the valley bottom signal is used to indicate that the waveform resonance of the resonant voltage reaches the valley bottom, and the target switching cycle is determined based on the feedback voltage;

[0388] The second processing module 1020 is used to determine the turn-off time corresponding to the power tube based on the voltage interval of the feedback voltage; there is a corresponding relationship between the candidate feedback voltage and the candidate turn-off time in the voltage interval, and the corresponding relationship is a functional relationship;

[0389] The third processing module 1030 is used to control the power tube to be turned on at a valley corresponding to a target valley signal in at least one valley signal based on the turn-off time, the feedback voltage, the target voltage threshold and at least one valley signal.

[0390] According to the control device of the switching power supply system provided in the embodiment of the present application, different turn-off times are adaptively generated by the size of the feedback voltage, and then based on the turn-off time, the feedback voltage, the target voltage threshold and at least one valley signal, it is determined at which valley the power tube is turned on in at least one valley signal, so that the power tube can be turned on at the corresponding valley position, and the valley locking effect is better, avoiding the problem of the power tube switching back and forth between adjacent valleys or even multiple valleys due to changes in input voltage or load, thereby avoiding the problems of switching frequency disorder and increased output voltage ripple, and no audio noise is generated, thereby improving the overall efficiency of the switching power supply system.

[0391] In some embodiments, the control device of the switching power supply system may further include a fourth processing module, which is used to obtain multiple voltage intervals based on a target voltage threshold before determining the turn-off time corresponding to the power tube based on the voltage interval in which the feedback voltage is located; the target voltage threshold includes a target upper limit value, a first voltage threshold value, a second voltage threshold value and a target lower limit value arranged in sequence;

[0392] A corresponding relationship between the candidate feedback voltage and the candidate turn-off time in each voltage interval is established; the corresponding relationship is used to characterize the relationship between the candidate turn-off time and the change of the candidate feedback voltage, and the corresponding relationship includes a constant function or an inverse proportional function.

[0393] In some embodiments, the fourth processing module may also be used to:

[0394] When the lower limit value of the voltage interval is not less than the target upper limit value, the corresponding relationship is determined as a first linear function; the first linear function is a constant function, and the output value of the first linear function is the minimum off time;

[0395] When the upper limit value of the voltage interval is less than the target upper limit value, and the lower limit value of the voltage interval is greater than the first voltage threshold value, the corresponding relationship is determined as a second linear function; the second linear function is an inverse proportional function, the minimum output value of the second linear function in the voltage interval is the minimum off time, and the maximum output value of the second linear function in the voltage interval is the first off time;

[0396] When the upper limit value of the voltage interval is less than the first voltage threshold value, and the lower limit value of the voltage interval is greater than the second voltage threshold value, the corresponding relationship is determined as a third linear function; the third linear function is an inverse proportional function, the minimum output value of the third linear function within the voltage interval is the first off-time, and the maximum output value of the third linear function within the voltage interval is the second off-time;

[0397] When the upper limit value of the voltage interval is less than the second voltage threshold value, and the lower limit value of the voltage interval is greater than the target lower limit value, the corresponding relationship is determined as a fourth linear function; the fourth linear function is an inverse proportional function, the minimum output value of the fourth linear function in the voltage interval is the second off-time, and the maximum output value of the fourth linear function in the voltage interval is the maximum off-time;

[0398] When the upper limit value of the voltage interval is less than the target lower limit value, the corresponding relationship is determined as a fifth linear function; the fifth linear function is a constant function, and the output value of the fifth linear function is the maximum off-time.

[0399] In some embodiments, the third processing module 1030 may also be used to:

[0400] Based on the turn-off moment, turn-off time, feedback voltage and target voltage threshold of the power tube within the target switching cycle, a turn-off time signal corresponding to the power tube is obtained;

[0401] When the off-time signal coincides with a first valley signal in at least one valley signal, the power tube is controlled to be turned on at the valley corresponding to the target valley signal; the first valley signal is a valley signal before the target valley signal.

[0402] In some embodiments, the switching power supply system includes a target capacitor, and the third processing module 1030 may also be used to:

[0403] Determine a generation time of a turn-off time signal based on the turn-off moment and the turn-off time;

[0404] Based on the feedback voltage, the target voltage threshold and the capacitor voltage corresponding to the target capacitance, a shutdown time signal is generated at the generation time; the target voltage threshold includes a target upper limit value, a first voltage threshold value, a second voltage threshold value and a target lower limit value arranged in sequence.

[0405] In some embodiments, the switching power supply system includes a first switch connected in series with the target capacitor, and a second switch, a third switch, and a fourth switch connected in parallel with the target capacitor respectively; the third processing module 1030 may also be used for:

[0406] When the capacitor voltage reaches the target upper limit value, the first switch is controlled to be disconnected, and the target capacitor ends the charging mode;

[0407] When the feedback voltage is greater than the first voltage threshold, the second switch and the third switch are controlled to be closed, and the first switch and the fourth switch are controlled to be opened, so that the target capacitor enters a discharge mode, and when the capacitor voltage in the discharge mode is less than the feedback voltage, a turn-off time signal is generated;

[0408] When the feedback voltage is less than the first voltage threshold and greater than the second voltage threshold, the second switch is controlled to be closed, and the first switch, the third switch and the fourth switch are controlled to be opened, so that the target capacitor enters the discharge mode, and when the capacitor voltage in the discharge mode is less than the feedback voltage, a turn-off time signal is generated;

[0409] When the feedback voltage is less than the second voltage threshold, the third switch is controlled to close, and the first switch, the second switch and the fourth switch are controlled to open, and the target capacitor enters the discharge mode. When the capacitor voltage in the discharge mode is less than the feedback voltage, a shutdown time signal is generated.

[0410] In some embodiments, the switching power supply system includes a second comparator, a third comparator, and a fourth comparator, and the control device of the switching power supply system may further include a fifth processing module for:

[0411] generating a switch enable signal based on output results of the second comparator, the third comparator, and the fourth comparator;

[0412] Based on the switch enable signal, a switch corresponding to the switch enable signal among the first switch, the second switch, the third switch and the fourth switch is controlled to be closed.

[0413] 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 the electronic device, such as an integrated circuit or a chip. The electronic device can be a terminal, or other devices other than a terminal. Exemplarily, the electronic device can be a mobile phone, a tablet computer, a laptop computer, a PDA, a vehicle-mounted electronic device, a mobile Internet device (Mobile Internet Device, MID), an augmented reality (augmented reality, AR) / virtual reality (virtual reality, VR) device, a robot, a wearable device, an ultra-mobile personal computer (ultra-mobile personal computer, UMPC), a netbook or a personal digital assistant (personal digital assistant, PDA), etc., and can also be a server, a network attached storage (Network Attached Storage, NAS), a personal computer (personal computer, PC), a television (television, TV), a teller machine or a self-service machine, etc., which is not specifically limited in the embodiment of the present application.

[0414] 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.

[0415] The control device of the switching power supply system provided in the embodiment of the present application can achieve Figures 1 to 9 To avoid repetition, the various processes implemented by the method embodiment are not described here.

[0416] In some embodiments, Fig.11 As shown, an embodiment of the present application also provides an electronic device 1100, including a processor 1101, a memory 1102, and a computer program stored in the memory 1102 and executable on the processor 1101. When the program is executed by the processor 1101, 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.

[0417] 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.

[0418] On the other hand, the present application also provides a computer program product, which includes a computer program stored on a non-transitory computer-readable storage medium, and the computer program includes program instructions. When the program instructions are executed by a computer, the computer can execute 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.

[0419] On the other hand, 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, it is implemented to execute the various processes of the control method embodiment of the above-mentioned switching power supply system and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0420] On the other hand, 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.

[0421] 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.

[0422] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0423] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, by hardware. Based on this understanding, the above technical solution can be essentially or in other words, the part that contributes to the relevant technology can be embodied in the form of a software product, which can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiment.

[0424] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A control method for a switching power supply system, characterized in that: include: When the power tube in the switching power supply system is in the off state, a feedback voltage, a target voltage threshold and at least one valley bottom signal corresponding to the switching power supply system in a target switching cycle are obtained; the valley bottom signal is used to characterize that the waveform resonance of the resonant voltage reaches the valley bottom, and the target switching cycle is determined based on the feedback voltage; Based on the target voltage threshold, a plurality of voltage intervals are obtained; The target voltage threshold comprises a target upper limit value, a first voltage threshold value, a second voltage threshold value and a target lower limit value arranged in sequence; Establishing a corresponding relationship between the candidate feedback voltage and the candidate turn-off time in each of the voltage intervals; the corresponding relationship is used to characterize the relationship between the candidate turn-off time and the change of the candidate feedback voltage; In a case where the lower limit value of the voltage interval is not less than the target upper limit value, the corresponding relationship is determined as a first linear function; the first linear function is a constant function, and an output value of the first linear function is a minimum off time; When the upper limit value of the voltage interval is less than the target upper limit value, and the lower limit value of the voltage interval is greater than the first voltage threshold value, the corresponding relationship is determined as a second linear function; the second linear function is an inverse proportional function, the minimum output value of the second linear function within the voltage interval is the minimum off time, and the maximum output value of the second linear function within the voltage interval is the first off time; When the upper limit value of the voltage interval is less than the first voltage threshold value, and the lower limit value of the voltage interval is greater than the second voltage threshold value, the corresponding relationship is determined as a third linear function; the third linear function is an inverse proportional function, the minimum output value of the third linear function within the voltage interval is the first turn-off time, and the maximum output value of the third linear function within the voltage interval is the second turn-off time; When the upper limit value of the voltage interval is less than the second voltage threshold value, and the lower limit value of the voltage interval is greater than the target lower limit value, the corresponding relationship is determined as a fourth linear function; the fourth linear function is an inverse proportional function, the minimum output value of the fourth linear function within the voltage interval is the second off time, and the maximum output value of the fourth linear function within the voltage interval is the maximum off time; When the upper limit value of the voltage interval is less than the target lower limit value, the corresponding relationship is determined as a fifth linear function; the fifth linear function is a constant function, and an output value of the fifth linear function is the maximum off time; Determining a turn-off time corresponding to the power tube based on the voltage interval of the feedback voltage; Based on the turn-off time, the feedback voltage, the target voltage threshold and the at least one valley signal, the power tube is controlled to be turned on at a valley corresponding to a target valley signal in the at least one valley signal.

2. The control method of the switching power supply system according to claim 1, characterized in that: The controlling the power tube to be turned on at a valley corresponding to a target valley signal in the at least one valley signal based on the turn-off time, the feedback voltage, the target voltage threshold and the at least one valley signal comprises: Acquire a turn-off time signal corresponding to the power tube based on the turn-off moment of the power tube within the target switching cycle, the turn-off time, the feedback voltage, and the target voltage threshold; When the turn-off time signal coincides with a first valley signal among the at least one valley signal, the power tube is controlled to be turned on at the valley corresponding to the target valley signal; the first valley signal is a valley signal before the target valley signal.

3. The control method of the switching power supply system according to claim 2, characterized in that: The switching power supply system includes a target capacitor, and acquiring a turn-off time signal corresponding to the power tube based on the turn-off moment of the power tube in the target switching cycle, the turn-off time, the feedback voltage, and the target voltage threshold, includes: Based on the shut-off moment and the shut-off time, determining a time to generate the shut-off time signal; Based on the feedback voltage, the target voltage threshold and the capacitor voltage corresponding to the target capacitance, the shutdown time signal is generated at the generation time; the target voltage threshold includes a target upper limit value, a first voltage threshold, a second voltage threshold and a target lower limit value arranged in sequence.

4. The control method of the switching power supply system according to claim 3, characterized in that: The switching power supply system includes a first switch connected in series with the target capacitor, and a second switch, a third switch, and a fourth switch connected in parallel with the target capacitor respectively; the generating the turn-off time signal at the generating time based on the feedback voltage, the target voltage threshold, and the capacitor voltage corresponding to the target capacitor includes: When the capacitor voltage reaches the target upper limit value, the first switch is controlled to be disconnected, and the target capacitor ends the charging mode; When the feedback voltage is greater than the first voltage threshold, the second switch and the third switch are controlled to be closed, and the first switch and the fourth switch are controlled to be opened, so that the target capacitor enters a discharge mode, and when the capacitor voltage in the discharge mode is less than the feedback voltage, the turn-off time signal is generated; When the feedback voltage is less than the first voltage threshold and greater than the second voltage threshold, the second switch is controlled to be closed, and the first switch, the third switch and the fourth switch are controlled to be opened, so that the target capacitor enters the discharge mode, and when the capacitor voltage in the discharge mode is less than the feedback voltage, the turn-off time signal is generated; When the feedback voltage is less than the second voltage threshold, the third switch is controlled to be closed, and the first switch, the second switch and the fourth switch are controlled to be disconnected, and the target capacitor enters the discharge mode. When the capacitor voltage in the discharge mode is less than the feedback voltage, the turn-off time signal is generated.

5. The control method of the switching power supply system according to claim 4, characterized in that: The switching power supply system includes a second comparator, a third comparator and a fourth comparator, and the method further includes: generating a switch enable signal based on output results of the second comparator, the third comparator and the fourth comparator; Based on the switch enable signal, a switch among the first switch, the second switch, the third switch and the fourth switch corresponding to the switch enable signal is controlled to be closed.

6. A switching power supply system based on the control method of the switching power supply system according to any one of claims 1 to 5, characterized in that: include: Power tube; A valley bottom detection module, the valley bottom detection module is used to output at least one valley bottom signal; A shut-off time module, wherein an input terminal of the shut-off time module is used to receive a feedback voltage; A valley locking module, wherein an input end of the valley locking module is respectively connected to an output end of the valley detection module and an output end of the shutdown time module; A driving module, wherein an input end of the driving module is connected to an output end of the valley locking module, and an output end of the driving module is connected to the power tube.

7. The switching power supply system according to claim 6, characterized in that: Also includes: A PWM comparison module, wherein one input end of the PWM comparison module is used to receive the feedback voltage, and another input end of the PWM comparison module is connected to a sampling resistor corresponding to a source end of the power tube; A trigger module, one input end of the trigger module is connected to the output end of the valley locking module, another input end of the trigger module is connected to the output end of the PWM comparison module, and the output end of the trigger module is connected to the input end of the driving module.

8. The switching power supply system according to claim 6, characterized in that: The off time module comprises: A clamping circuit; the clamping circuit is used to receive the feedback voltage; A first comparator; a non-inverting input terminal of the first comparator is connected to an output terminal of the clamping circuit; A first rising edge detection circuit; an input end of the first rising edge detection circuit is connected to an output end of the first comparator, and an output end of the first rising edge detection circuit is connected to the valley locking module; A target capacitor; the target capacitor is connected to the inverting input terminal of the first comparator; A first switch; the first switch is connected in series with the target capacitor; A second switch; the second switch is connected in parallel with the target capacitor; A third switch; the third switch is connected in parallel with the target capacitor; a fourth switch; the fourth switch is connected in parallel with the target capacitor; A switch control circuit; the switch control circuit is connected to the target capacitor, the first switch, the second switch, the third switch and the fourth switch respectively.

9. The switching power supply system according to claim 8, characterized in that: The clamping circuit comprises: a first operational amplifier; a non-inverting input terminal of the first operational amplifier is used to receive a target upper limit value, and an inverting input terminal of the first operational amplifier is used to receive the feedback voltage; NMOS tube; the input end of the NMOS tube is connected to the output end of the first operational amplifier, one output end of the NMOS tube is grounded, and the other output end of the NMOS tube is connected to the inverting input end of the first operational amplifier; a second operational amplifier; a non-inverting input terminal of the second operational amplifier is used to receive the target lower limit value, an inverting input terminal of the second operational amplifier is used to receive the feedback voltage, and the inverting input terminal of the second operational amplifier is connected to another output terminal of the NMOS tube; PMOS tube; the input end of the PMOS tube is connected to the output end of the second operational amplifier, one output end of the PMOS tube is connected to the power supply, and the other output end of the PMOS tube is connected to the inverting input end of the second operational amplifier.

10. The switching power supply system according to claim 8, characterized in that: The switch control circuit comprises: A second comparator; a non-inverting input terminal of the second comparator is used to receive a target upper limit value, and an inverting input terminal of the second comparator is used to receive a capacitance voltage of the target capacitance; A third comparator; the non-inverting input terminal of the third comparator is used to receive the first voltage threshold, and the inverting input terminal of the third comparator is used to receive the feedback voltage; A fourth comparator; a non-inverting input terminal of the fourth comparator is used to receive the feedback voltage, and an inverting input terminal of the fourth comparator is used to receive a second voltage threshold; A first falling edge detection circuit; the first falling edge detection circuit is connected to the output end of the second comparator; A second rising edge detection circuit; the second rising edge detection circuit is used to detect the rising edge of the driving signal; The second falling edge detection circuit is used to detect the falling edge of the driving signal.

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 5 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 5 is implemented.

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