Control method of switching power supply circuit, controller, switching power supply circuit and medium

Abstract

The present invention provides a control method, controller, switching power supply circuit and medium for a switching power supply circuit. The switching power supply circuit includes an upper switching tube and a lower switching tube that cannot be turned on at the same time, and a resonant circuit is present in the switching power supply circuit; the method includes: in the process of controlling the upper switching tube and the lower switching tube in a symmetrical width modulation manner, if it is detected that the gain trend of the switching power supply circuit has changed, then controlling the upper switching tube and the lower switching tube in a complementary width modulation manner; wherein the preset dead time of the complementary width modulation manner is not greater than the resonant period of the resonant circuit, and the gain trend includes the gain increasing with the increase of the duty cycle, or the gain decreasing with the increase of the duty cycle. The control method of the present application will no longer have an excessively long dead time, avoid the problem of re-triggering hard-on, and can make the gain trend of the switching power supply circuit monotonic, avoid affecting its efficiency and avoid more serious EMC or EMI effects.

Description

Technical Field

[0001] The present invention relates to the technical field of switching power supplies, and in particular to a control method, a controller, a switching power supply circuit and a medium. Background Art

[0002] When a switching power supply circuit is controlled in a bandwidth modulation manner, the symmetrical bandwidth modulation method is usually the preferred bandwidth modulation method due to its simple underlying configuration and simple control.

[0003] However, when the switching power supply circuit is lightly loaded or inputs a high voltage, and a symmetrical width modulation method is used to control the switching power supply circuit, the duty cycle is very small, resulting in an excessively long dead time. During the dead time, since the switching tubes are all in the off state, the capacitors and inductors (including parasitic capacitance and parasitic inductance) in the circuit may resonate, causing unstable potential parameters at certain locations in the circuit, thereby causing devices that could otherwise achieve soft switching to hard switching, affecting efficiency and possibly causing more serious EMC (Electro Magnetic Compatibility) or EMI (Electro Magnetic Interference), which is detrimental to the switching power supply. Summary of the Invention

[0004] Embodiments of the present invention provide a control method, controller, switching power supply circuit, and medium for a switching power supply circuit to address the problem in the prior art that, when the switching power supply circuit is lightly loaded or has a high input voltage, it controls the circuit in a symmetrical width modulation manner, which may cause hard switching of devices that could otherwise achieve soft switching, affecting efficiency and potentially causing more severe EMC or EMI effects, which is detrimental to the switching power supply.

[0005] In a first aspect, an embodiment of the present invention provides a method for controlling a switching power supply circuit, wherein the switching power supply circuit includes an upper switching tube and a lower switching tube that cannot be turned on at the same time, and the switching power supply circuit has a resonant circuit; the method for controlling the switching power supply circuit includes:

[0006] During the process of controlling the upper switch tube and the lower switch tube in a symmetrical width modulation manner, if a change in the gain trend of the switching power supply circuit is detected, the upper switch tube and the lower switch tube are controlled in a complementary width modulation manner; wherein the preset dead time of the complementary width modulation manner is no greater than the resonant period of the resonant circuit, and the gain trend includes the gain increasing with increasing duty cycle, or the gain decreasing with increasing duty cycle.

[0007] In a possible implementation, if a change in the gain trend of the switching power supply circuit is detected, before controlling the upper switch tube and the lower switch tube in a complementary width modulation manner, the method further includes:

[0008] Within a preset time, the symmetrical bandwidth modulation mode is gradually adjusted to a complementary bandwidth modulation mode.

[0009] In one possible implementation, gradually adjusting the symmetrical bandwidth modulation mode to the complementary bandwidth modulation mode within a preset time period includes:

[0010] Keeping the control mode of the first switch unchanged, the duty cycle of the second switch is controlled to gradually increase until the first switch and the second switch are complementarily turned on when the preset dead time is not in progress.

[0011] The first switch tube is one of the upper switch tube and the lower switch tube, and the second switch tube is the other of the upper switch tube and the lower switch tube.

[0012] In a possible implementation, controlling the duty cycle of the second switch tube to gradually increase includes:

[0013] According to the preset step size, the duty cycle of the second switch tube is controlled to increase linearly.

[0014] In a possible implementation, detecting that a gain trend of a switching power supply circuit changes includes:

[0015] The duty cycle maintains an increasing or decreasing direction unchanged. If it is detected that the detection parameter of the switching power supply circuit changes from an upward trend to a downward trend or from a downward trend to an upward trend, it is determined that the gain trend of the switching power supply circuit has changed, wherein the detection parameter includes the gain or the output voltage or the output current.

[0016] In a possible implementation, the resonant circuit includes parasitic capacitance and / or parasitic inductance of the switching power supply circuit.

[0017] In a possible implementation, the control method of the switching power supply circuit further includes:

[0018] In the process of controlling the upper switch tube and the lower switch tube in a symmetrical width modulation manner, if it is detected that the duty cycle of each switch tube of the switching power supply circuit is less than the preset minimum duty cycle, the upper switch tube and the lower switch tube are controlled in a complementary width modulation manner.

[0019] In a second aspect, an embodiment of the present invention provides a controller comprising a memory and a processor, wherein the memory is used to store a computer program, and the processor is used to call and run the computer program stored in the memory to execute the control method of the switching power supply circuit as described in the first aspect or any possible implementation of the first aspect.

[0020] In a third aspect, an embodiment of the present invention provides a switching power supply circuit, comprising the controller according to the second aspect and an upper switch tube and a lower switch tube that cannot be turned on at the same time; the switching power supply circuit has a resonant circuit;

[0021] The upper switch tube and the lower switch tube are controlled by a controller.

[0022] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, it implements the steps of the control method of the switching power supply circuit as described in the first aspect or any possible implementation method of the first aspect.

[0023] Embodiments of the present invention provide a control method, controller, switching power supply circuit, and medium for a switching power supply circuit. The switching power supply circuit includes an upper switching transistor and a lower switching transistor that cannot be turned on simultaneously, and a resonant circuit. Because a symmetrical bandwidth modulation scheme has strong input adaptability, can achieve precise control of output signals, is relatively simple to control, and has relatively simple underlying configuration, the method preferentially controls the upper and lower switching transistors symmetrically. However, during the symmetrical bandwidth modulation control process, if a change in the gain trend of the switching power supply circuit is detected, the upper and lower switching transistors are controlled using a complementary bandwidth modulation scheme. This allows the switching power supply circuit to be controlled using a complementary bandwidth modulation scheme when a change in the gain trend of the switching power supply circuit is detected, i.e., when a hard-on problem has just occurred or is about to occur, control is switched to a complementary bandwidth modulation scheme. Because the preset dead time of the complementary bandwidth modulation scheme is no greater than the resonant period of the resonant circuit, an excessively long dead time is eliminated, preventing the hard-on problem from being triggered again. This allows the gain trend of the switching power supply circuit to be monotonic, thereby preventing efficiency degradation and further EMC or EMI effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 1 is a flow chart of a control method for a switching power supply circuit provided by an embodiment of the present invention;

[0026] Figure 2 This is one example of a switching power supply circuit provided by an embodiment of the present invention;

[0027] Figure 3 is a schematic diagram of a symmetrical width adjustment method provided by an embodiment of the present invention;

[0028] Figure 4 is a schematic diagram of a complementary bandwidth modulation method provided by an embodiment of the present invention;

[0029] Figure 5 A schematic structural diagram of a control device for a switching power supply circuit provided by an embodiment of the present invention;

[0030] Figure 6 is a schematic diagram of a controller provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0031] In the following description, specific details such as particular system structures and techniques are provided for purposes of illustration, not limitation, to facilitate a thorough understanding of the embodiments of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.

[0032] In order to make the purpose, technical solutions and advantages of the present invention more clear, specific embodiments will be described below with reference to the accompanying drawings.

[0033] See also Figure 1 , which shows a flow chart of the implementation of the control method of the switching power supply circuit provided by an embodiment of the present invention. The execution subject of the control method of the switching power supply circuit can be a controller.

[0034] The switching power supply circuit includes an upper switching tube and a lower switching tube that cannot be turned on at the same time, and a resonant circuit is present in the switching power supply circuit. The resonant circuit can be a circuit in which components such as an inductor and / or a capacitor actually present in the switching power supply circuit resonate, or a circuit in which parasitic capacitance and / or parasitic inductance actually present in the switching power supply circuit resonate, or a circuit in which an inductor, capacitor, parasitic capacitance, and / or parasitic inductance actually present in the switching power supply circuit resonate.

[0035] The upper switch tube and the lower switch tube that cannot be turned on at the same time can be the upper switch tube and the lower switch tube on the same bridge arm in the switching power supply circuit. The upper switch tube is the switch tube on the upper half bridge arm of the same bridge arm, and the lower switch tube is the switch tube on the lower half bridge arm of the same bridge arm. The switching power supply circuit may include at least one bridge arm, for example, it may include one bridge arm, two bridge arms, three bridge arms, etc., and no specific limitation is made here. The upper switch tube and the lower switch tube on each bridge arm can be controlled using the control method provided in the present application. Among them, the upper switch tube and the lower switch tube can be MOS tubes, IGBT modules, etc., or other applicable switch tubes, and no specific limitation is made here.

[0036] For example, Figure 2 As an example of a switching power supply circuit, Figure 2The switching power supply circuit shown includes two bridge arms: a first arm and a second arm. The first arm includes an upper switch Q1 and a lower switch Q2, while the second arm includes an upper switch Q3 and a lower switch Q4. This switching power supply circuit includes a resonant circuit composed of an inductor and a capacitor. Simultaneous conduction of both switches in the first arm would result in a short circuit; therefore, both cannot be turned on simultaneously. The same applies to the two switches in the second arm.

[0037] Symmetrical width modulation means that the duty cycles of the upper and lower switches in the same bridge arm are identical, but one of the switches turns on 180 degrees later. The duty cycles of the two switches can be determined based on the corresponding control loops (current loop, voltage loop, and / or power loop). For example, PI control can be performed based on the output voltage feedback signal and a given voltage signal to output the corresponding duty cycle.

[0038] by Figure 2 Take the upper switch tube Q1 and the lower switch tube Q2 in the first bridge arm as an example. Figure 3 As shown, using the symmetrical width modulation method, Q2 is turned on 180 degrees later, then the driving signal of Q1 and the driving signal of Q2 are as follows Figure 3 As shown in the figure, the duty cycles of the two are the same. When the drive signal is 1, it means that the corresponding switch tube is turned on; when the drive signal is 0, it means that the corresponding switch tube is turned off.

[0039] Figure 3 T1 represents the dead time of the symmetrical width modulation method. During this dead time, both the upper switch Q1 and the lower switch Q2 are off. When the duty cycle is small, the dead time is longer. As mentioned above, during this dead time, both the upper switch Q1 and the lower switch Q2 are off. The capacitors and inductors (including parasitic capacitance and inductance) in the circuit may resonate, causing unstable potential parameters at certain locations in the circuit. This can cause devices that could otherwise achieve soft switching to hard switching, affecting efficiency and potentially causing more serious EMC (Electro Magnetic Compatibility) or EMI (Electro Magnetic Interference) effects, which are detrimental to the switching power supply.

[0040] In order to solve the above problems, an embodiment of the present application provides a control method for a switching power supply circuit.

[0041] See also Figure 1 , the control method of the above-mentioned switching power supply circuit includes:

[0042] In S101, during the process of controlling the upper switch tube and the lower switch tube in a symmetrical width modulation manner, if it is detected that a change in the gain trend of the switching power supply circuit occurs, the upper switch tube and the lower switch tube are controlled in a complementary width modulation manner; wherein the preset dead time of the complementary width modulation manner is no greater than the resonant period of the resonant circuit, and the gain trend includes the gain increasing with an increase in the duty cycle, or the gain decreasing with an increase in the duty cycle.

[0043] When controlling the upper and lower switching tubes of a switching power supply circuit using symmetrical bandwidth modulation, if resonance occurs within the dead time, resulting in a device hard-on problem or an imminent device hard-on problem, the gain trend of the switching power supply circuit may shift, causing the gain trend of the switching power supply circuit to exhibit non-monotonicity. Therefore, if a shift in the gain trend of the switching power supply circuit is detected during the symmetrical bandwidth modulation process, it is determined that the gain trend of the switching power supply circuit exhibits non-monotonicity, indicating that a device hard-on problem has occurred or is imminent in the switching power supply circuit, and it is necessary to switch to a complementary bandwidth modulation process to control the upper and lower switching tubes.

[0044] In the complementary bandwidth modulation method, both the upper and lower switches are off during the preset dead time. Because the preset dead time is no longer than the resonant cycle of the resonant circuit, that is, the duration of the preset dead time is no longer than the duration of one resonant cycle of the resonant circuit, the short duration, that is, the duration during which both the upper and lower switches are off, is short. During this duration, the resonant circuit will not resonate, or will resonate at most once, and will not affect the circuit.

[0045] Complementary bandwidth modulation means that the duty cycles of the upper and lower switches in the same bridge arm are complementary during the non-preset dead time, and the upper and lower switches are not turned on at the same time. In other words, in complementary bandwidth modulation, during the preset dead time, both the upper and lower switches in the same bridge arm are turned off, and during the non-preset dead time, the upper and lower switches in the same bridge arm are turned on complementary to each other.

[0046] For example, Figure 2 Taking the upper switch tube Q1 and the lower switch tube Q2 in the first bridge arm as an example, if the complementary width modulation method is adopted, the driving signal of Q1 and the driving signal of Q2 are as follows: Figure 4 As shown, Figure 4 In the figure, T2 is the preset dead time. When Q1 and Q2 switch states, there is a preset dead time to prevent both from being turned on at the same time.

[0047] The gain trend of a switching power supply circuit includes an increase in gain as the duty cycle increases, or a decrease in gain as the duty cycle increases. A change in the gain trend of a switching power supply circuit includes a change from an increase in gain as the duty cycle increases to a decrease in gain as the duty cycle increases, or a change from a decrease in gain as the duty cycle increases to an increase in gain as the duty cycle increases. The duty cycle in the gain trend is the minimum value among the duty cycles of the switching tubes in the switching power supply circuit. In a symmetrical width modulation method, the duty cycles of the upper and lower switching tubes are the same, so the duty cycle in the gain trend can be the duty cycle of any one of the switching tubes. If, in a complementary width modulation method, the duty cycles of the upper and lower switching tubes are different, the duty cycle in the gain trend is the smaller of the two duty cycles.

[0048] The switching power supply circuit provided in this embodiment includes an upper switching transistor and a lower switching transistor that cannot be turned on simultaneously, and a resonant circuit is present in the switching power supply circuit. Since the symmetrical bandwidth modulation method has strong input adaptability, can achieve precise control of the output signal, is relatively simple to control, and has relatively simple underlying configuration, this method preferentially controls the upper and lower switching transistors symmetrically. However, during the symmetrical bandwidth modulation process, if a change in the gain trend of the switching power supply circuit is detected, the upper and lower switching transistors are controlled using a complementary bandwidth modulation method. Thus, upon detecting a change in the gain trend of the switching power supply circuit, i.e., upon detecting that a hard-turn-on problem has just occurred or is about to occur, the switching power supply circuit can be switched to the complementary bandwidth modulation method. Since the preset dead time of the complementary bandwidth modulation method is no greater than the resonant period of the resonant circuit, an excessively long dead time is avoided, thereby preventing the hard-turn-on problem from being triggered again. The gain trend of the switching power supply circuit can be made monotonic, thereby avoiding affecting its efficiency and preventing more serious EMC or EMI effects.

[0049] This embodiment takes into account the advantages of the symmetrical width modulation method, which has strong input adaptability, can achieve precise control of output signals, and has relatively simple underlying configuration and control. When controlling the switching power supply circuit in the width modulation method, the symmetrical width modulation method is first selected to control the switching power supply circuit. When problems arise with the symmetrical width modulation control, such as hard-on problems caused by a long dead time and gain non-monotonicity problems, the complementary width modulation method is switched to solve the problems with the symmetrical width modulation method. This can take into account the advantages of the symmetrical width modulation method and solve the problems with the symmetrical width modulation method in a timely manner when problems are found, thereby avoiding affecting the efficiency of the switching power supply circuit and avoiding more serious EMC or EMI effects.

[0050] In some embodiments, in the above S101, if a change in the gain trend of the switching power supply circuit is detected, before controlling the upper switch tube and the lower switch tube in a complementary width modulation manner, the process further includes:

[0051] Within a preset time, the symmetrical bandwidth modulation mode is gradually adjusted to a complementary bandwidth modulation mode.

[0052] When changing from a symmetrical bandwidth modulation mode to a complementary bandwidth modulation mode, due to the change in duty cycle, a direct switch may affect the operation of the switching power supply circuit, causing problems in the switching power supply circuit. Therefore, this embodiment gradually adjusts the symmetrical bandwidth modulation mode to the complementary bandwidth modulation mode over a preset time period, rather than switching to the complementary bandwidth modulation mode directly in one step. This allows the control mode of the switching power supply circuit to change gradually, avoiding problems. After the symmetrical bandwidth modulation mode is adjusted to the complementary bandwidth modulation mode, the complementary bandwidth modulation mode can be used to control the switching power supply circuit subsequently.

[0053] Among them, the preset time length is a relatively short time length, and the setting of the time length can satisfy the gradual and gentle change of the control mode of the switching power supply circuit, while avoiding the hard opening problem and the gain trend non-monotonicity problem under the symmetrical width modulation mode.

[0054] In some embodiments, in the above S101, the step of gradually adjusting the symmetrical bandwidth modulation mode to the complementary bandwidth modulation mode within a preset time period includes:

[0055] Keeping the control mode of the first switch unchanged, the duty cycle of the second switch is controlled to gradually increase until the first switch and the second switch are complementarily turned on when the preset dead time is not in progress.

[0056] The first switch is one of the upper and lower switches, and the second switch is the other of the upper and lower switches. That is, the first switch is the upper switch and the second switch is the lower switch; or, the first switch is the lower switch and the second switch is the upper switch.

[0057] In this embodiment, the control mode of the first switch tube remains unchanged, which can be understood as the control loop of the first switch tube remains unchanged, which is the same as the control loop of the first switch tube when the switching power supply circuit is controlled in a symmetrical width modulation manner.

[0058] For the same bridge arm, the control mode of the first switch tube remains unchanged. In order to adjust the symmetrical width modulation mode to the complementary width modulation mode, the duty cycle of the second switch tube in the same bridge arm needs to be gradually increased until the first switch tube and the second switch tube are complementarily turned on during the non-preset dead time. That is, during the non-preset dead time, when the first switch tube is turned on, the second switch tube is turned off, and when the first switch tube is turned off, the second switch tube is turned on. During the non-preset dead time, the duty cycles of the two are complementary.

[0059] It should be noted that the switching power supply circuit in the embodiment of the present application can be an LLC resonant circuit or other types of switching power supply circuits with resonant circuits, and no specific restrictions are made here. Among them, the LLC resonant circuit can be a half-bridge LLC resonant circuit or a Figure 2 The full-bridge LLC resonant circuit shown can also be a three-phase LLC resonant circuit.

[0060] Exemplarily, the switching power supply circuit can be a half-bridge LLC resonant circuit, then the corresponding controlled bridge arm includes only one bridge arm. For this bridge arm, the control method of the upper switch tube can be kept unchanged, and the duty cycle of the lower switch tube can be controlled to gradually increase until the upper switch tube and the lower switch tube are complementarily turned on during non-preset dead time.

[0061] The switching power supply circuit can also be Figure 2 For the full-bridge LLC resonant circuit shown, the corresponding controlled bridge arm includes two bridge arms, namely the first bridge arm and the second bridge arm. For the first bridge arm, the control method of the upper switch Q1 of the first bridge arm can be maintained unchanged, and the duty cycle of the lower switch Q2 of the first bridge arm can be gradually increased until the upper switch Q1 and the lower switch Q2 of the first bridge arm are complementary and conductive during the non-preset dead time. For the second bridge arm, the control method of the lower switch Q4 of the second bridge arm is consistent with the control method of the upper switch Q1 of the first bridge arm, and the control method of the upper switch Q3 of the second bridge arm is consistent with the control method of the lower switch Q2 of the first bridge arm.

[0062] The switching power supply circuit can also be a three-phase LLC resonant circuit, in which case the corresponding controlled bridge arm includes three bridge arms, namely the third bridge arm, the fourth bridge arm, and the fifth bridge arm. The third bridge arm, the fourth bridge arm, and the fifth bridge arm are each 120 degrees out of phase for phase control. For the third bridge arm, the fourth bridge arm, and the fifth bridge arm, the control method of the upper switch tube of each bridge arm can be kept unchanged, and the duty cycle of the lower switch tube of each bridge arm can be controlled to gradually increase until the upper switch tube of each bridge arm and the corresponding lower switch tube are complementary turned on during non-preset dead time. In other words, the control method of the third bridge arm, the fourth bridge arm, and the fifth bridge arm are the same, except that the fourth bridge arm is controlled 120 degrees later than the third bridge arm, and the fifth bridge arm is controlled 120 degrees later than the fourth bridge arm.

[0063] In some embodiments, the step of gradually increasing the duty cycle of the second switch tube includes:

[0064] According to the preset step size, the duty cycle of the second switch tube is controlled to increase linearly.

[0065] The preset step size may be determined based on the current duty cycle, the target duty cycle, and the preset duration of the second switch tube.

[0066] By controlling the duty cycle of the second switch tube to increase linearly according to a preset step size, the control mode of the switching power supply circuit can be changed linearly, thereby avoiding a series of problems caused by sudden changes.

[0067] In some embodiments, detecting a change in the gain trend of the switching power supply circuit includes:

[0068] The duty cycle maintains an increasing or decreasing direction unchanged. If it is detected that the detection parameter of the switching power supply circuit changes from an upward trend to a downward trend or from a downward trend to an upward trend, it is determined that the gain trend of the switching power supply circuit has changed, wherein the detection parameter includes the gain or the output voltage or the output current.

[0069] The gain of a switching power supply circuit is the ratio of its output parameter to its input parameter. When the switching power supply circuit is operating normally, its input parameter typically does not change significantly. Therefore, in embodiments of the present application, when the duty cycle remains unchanged in the direction of increase or decrease, the switching power supply circuit's gain trend is determined by detecting the changing trend of the switching power supply circuit's output voltage or output current, or directly detecting the changing trend of the switching power supply circuit's gain. This duty cycle is the duty cycle in the aforementioned gain trend.

[0070] When the duty cycle remains in an increasing or decreasing direction, if it is detected that the gain, output voltage or output current of the switching power supply circuit changes from an upward trend to a downward trend or from a downward trend to an upward trend, it is determined that the gain trend of the switching power supply circuit has changed; otherwise, it is determined that the gain trend of the switching power supply circuit has not changed.

[0071] In some embodiments, the resonant tank includes parasitic capacitance and / or parasitic inductance of the switching power supply circuit.

[0072] In this embodiment, the switching power supply circuit may resonate due to the presence of parasitic capacitance and / or parasitic inductance, and is not limited to the resonance of actual capacitance and / or inductance components in the switching power supply circuit.

[0073] In some embodiments, the control method of the switching power supply circuit further includes:

[0074] In the process of controlling the upper switch tube and the lower switch tube in a symmetrical width modulation manner, if it is detected that the duty cycle of each switch tube of the switching power supply circuit is less than the preset minimum duty cycle, the upper switch tube and the lower switch tube are controlled in a complementary width modulation manner.

[0075] As can be seen from the above, symmetrical bandwidth modulation means that the duty cycles of the upper and lower switches in the same bridge arm are the same, but one switch turns on 180 degrees later. Therefore, if the duty cycle of the switch in that bridge arm is too small, the dead time of that bridge arm will be too long, leading to hard-on and gain non-monotonicity. Therefore, when the duty cycle is detected to be too small, it is necessary to switch to complementary bandwidth modulation to control the switching power supply circuit to solve these problems.

[0076] However, for a full-bridge LLC resonant circuit, when a symmetrical width modulation method is used, the two switching tubes in the first bridge arm can be controlled according to the duty cycle output by the control loop, and the two switching tubes in the second bridge arm can be controlled according to a 50% duty cycle. Based on this situation, in this embodiment, when controlling the switching power supply circuit in a symmetrical width modulation method, if it is detected that the duty cycle of each switching tube in the switching power supply circuit is less than a preset minimum duty cycle, it can be understood that when it is detected that the minimum value of the duty cycle of each switching tube in the switching power supply circuit is less than or equal to the preset minimum duty cycle, the switching power supply circuit is controlled in a complementary width modulation method, that is, the upper switching tube and the lower switching tube are controlled in a complementary width modulation method.

[0077] The preset minimum duty cycle may be the maximum duty cycle when the aforementioned hard-on and gain non-monotonicity problems occur when the symmetrical width modulation method is used for control.

[0078] In some possible implementations, during the process of controlling the upper switch tube and the lower switch tube in a symmetrical width modulation manner, if it is detected that the duty cycle of each switch tube of the switching power supply circuit is less than a preset minimum duty cycle, then before controlling the upper switch tube and the lower switch tube in a complementary width modulation manner, the method further includes:

[0079] Within a preset time, the symmetrical bandwidth modulation mode is gradually adjusted to a complementary bandwidth modulation mode.

[0080] The specific implementation of this embodiment can refer to the above description and will not be repeated here.

[0081] In some possible implementations, if the switching power supply circuit is a resonant circuit, then before step S101, the method for controlling the switching power supply circuit further includes:

[0082] When the switching frequency of the switching power supply circuit is greater than a first preset frequency, the upper switch tube and the lower switch tube are controlled in a symmetrical width modulation manner.

[0083] The first preset frequency is a switching frequency used to distinguish between adjusting the resonant circuit's gain via frequency modulation and adjusting the resonant circuit's gain via width modulation. This can be set based on actual needs and is not specifically limited here. Frequency modulation controls the resonant circuit by adjusting the switching frequency, while maintaining a constant duty cycle. Width modulation controls the resonant circuit by adjusting the duty cycle, while maintaining a constant switching frequency.

[0084] The gain of the resonant circuit changes with the switching frequency. Usually, the gain first increases with the increase of the switching frequency. After reaching the peak, the gain decreases with the increase of the switching frequency. However, when the switching frequency increases to a certain level, the gain change of the resonant circuit is no longer obvious. At this time, it can be controlled by bandwidth modulation. Based on these characteristics of the resonant circuit, it is usually controlled by frequency modulation first. When the frequency modulation has little effect on it, the bandwidth modulation method is used to control it.

[0085] When the switching frequency of the switching power supply circuit is greater than the first preset frequency, the upper switch tube and the lower switch tube are controlled by means of width modulation. At this time, the switching frequency remains fixed, and the fixed frequency can be a frequency value greater than the first preset frequency. When the switching frequency of the switching power supply circuit is less than or equal to the first preset frequency, the upper switch tube and the lower switch tube are controlled by means of frequency modulation. At this time, the duty cycle remains unchanged.

[0086] Typically, under high-voltage gain conditions, such as heavy loads or low input voltage, the upper and lower switching transistors are controlled using frequency modulation. Under low-voltage gain conditions, such as light loads or high input voltage, the upper and lower switching transistors are controlled using width modulation. Therefore, the first preset frequency is greater than the switching frequency corresponding to the resonant point.

[0087] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0088] The following are device embodiments of the present invention. For details not fully described therein, reference may be made to the corresponding method embodiments described above.

[0089] Figure 5 A schematic diagram of the structure of a control device for a switching power supply circuit according to an embodiment of the present invention is shown. For ease of explanation, only the parts related to the embodiment of the present invention are shown, which are described in detail as follows:

[0090] The switching power supply circuit includes an upper switch tube and a lower switch tube that cannot be turned on at the same time, and there is a resonant circuit in the switching power supply circuit. Figure 5 As shown, the control device 30 of the switching power supply circuit may include: a width adjustment control module 31.

[0091] The bandwidth control module 31 is configured to control the upper and lower switching transistors in a complementary bandwidth modulation manner if, during the process of controlling the upper and lower switching transistors in a symmetrical bandwidth modulation manner, it detects a change in the gain trend of the switching power supply circuit. The complementary bandwidth modulation manner has a preset dead time no greater than the resonant period of the resonant circuit, and the gain trend includes either an increase in gain with an increase in duty cycle or a decrease in gain with an increase in duty cycle.

[0092] In a possible implementation, in the width modulation control module 31, if a change in the gain trend of the switching power supply circuit is detected, the following steps may be further performed before controlling the upper switch tube and the lower switch tube in a complementary width modulation manner:

[0093] Within a preset time, the symmetrical bandwidth modulation mode is gradually adjusted to a complementary bandwidth modulation mode.

[0094] In a possible implementation, the bandwidth control module 31 gradually adjusts the symmetrical bandwidth modulation mode to the complementary bandwidth modulation mode within a preset time period, including:

[0095] Keeping the control mode of the first switch unchanged, the duty cycle of the second switch is controlled to gradually increase until the first switch and the second switch are complementarily turned on when the preset dead time is not in progress.

[0096] The first switch tube is one of the upper switch tube and the lower switch tube, and the second switch tube is the other of the upper switch tube and the lower switch tube.

[0097] In a possible implementation, in the width adjustment control module 31, controlling the duty cycle of the second switch tube to gradually increase includes:

[0098] According to the preset step size, the duty cycle of the second switch tube is controlled to increase linearly.

[0099] In a possible implementation, in the width adjustment control module 31, detecting that a gain trend of the switching power supply circuit changes includes:

[0100] The duty cycle maintains an increasing or decreasing direction unchanged. If it is detected that the detection parameter of the switching power supply circuit changes from an upward trend to a downward trend or from a downward trend to an upward trend, it is determined that the gain trend of the switching power supply circuit has changed, wherein the detection parameter includes the gain or the output voltage or the output current.

[0101] In a possible implementation, the resonant circuit includes parasitic capacitance and / or parasitic inductance of the switching power supply circuit.

[0102] In a possible implementation, the width adjustment control module 31 is further configured to:

[0103] In the process of controlling the upper switch tube and the lower switch tube in a symmetrical width modulation manner, if it is detected that the duty cycle of each switch tube of the switching power supply circuit is less than the preset minimum duty cycle, the upper switch tube and the lower switch tube are controlled in a complementary width modulation manner.

[0104] Figure 6 Schematic diagram of a controller provided by an embodiment of the present invention. Figure 6 As shown, the controller 4 of this embodiment includes: a processor 40 and a memory 41. The memory 41 is used to store a computer program 42, and the processor 40 is used to call and run the computer program 42 stored in the memory 41 to perform the steps in the above-mentioned control method embodiments of the switching power supply circuit, such as Figure 1 Alternatively, the processor 40 is used to call and run the computer program 42 stored in the memory 41 to implement the functions of each module / unit in the above-mentioned device embodiments, such as Figure 5 The functionality of module 31 is shown.

[0105] For example, the computer program 42 may be divided into one or more modules / units, which are stored in the memory 41 and executed by the processor 40 to implement the present invention. The one or more modules / units may be a series of computer program instruction segments capable of implementing specific functions, which are used to describe the execution process of the computer program 42 in the controller 4. For example, the computer program 42 may be divided into Figure 5 Module 31 is shown.

[0106] The controller 4 may include, but is not limited to, a processor 40 and a memory 41. Those skilled in the art will understand that Figure 6 It is only an example of the controller 4 and does not constitute a limitation of the controller 4. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the controller may also include input and output devices, network access devices, buses, etc.

[0107] The processor 40 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor.

[0108] The memory 41 may be an internal storage unit of the controller 4, such as a hard disk or memory of the controller 4. The memory 41 may also be an external storage device of the controller 4, such as a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) card, a Flash Card, etc. equipped on the controller 4. Furthermore, the memory 41 may include both an internal storage unit of the controller 4 and an external storage device. The memory 41 is used to store the computer program and other programs and data required by the controller. The memory 41 may also be used to temporarily store data that has been output or is about to be output.

[0109] Corresponding to the above controller, this embodiment further provides a switching power supply circuit, comprising the above controller and an upper switch tube and a lower switch tube that cannot be turned on at the same time; the switching power supply circuit has a resonant circuit;

[0110] The upper switch tube and the lower switch tube are controlled by a controller.

[0111] For a detailed description of the switching power supply circuit, please refer to the relevant description in the aforementioned method, which will not be repeated here.

[0112] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0113] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant description of other embodiments.

[0114] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present invention.

[0115] In the embodiments provided by the present invention, it should be understood that the disclosed devices / controllers and methods can be implemented in other ways. For example, the device / controller embodiments described above are merely schematic. For example, the division of the modules or units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0116] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0117] In addition, the functional units in the various embodiments of the present invention may be integrated into a single processing unit, each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0118] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by the processor, it can implement the steps of the above-mentioned various current sharing control method embodiments. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device that can carry the computer program code, recording medium, U disk, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal and software distribution medium, etc.

[0119] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention 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. 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 various embodiments of the present invention, and should all be included in the scope of protection of the present invention.

Claims

1. A control method for a switching power supply circuit, characterized in that: The switching power supply circuit includes an upper switching tube and a lower switching tube that cannot be turned on at the same time, and the switching power supply circuit has a resonant circuit; the control method of the switching power supply circuit includes: During the process of controlling the upper switch tube and the lower switch tube in a symmetrical width modulation manner, if it is detected that a change in the gain trend of the switching power supply circuit occurs, the upper switch tube and the lower switch tube are controlled in a complementary width modulation manner; wherein the preset dead time of the complementary width modulation manner is no greater than the resonant period of the resonant circuit, and the gain trend includes an increase in gain as the duty cycle increases, or a decrease in gain as the duty cycle increases.

2. The control method of the switching power supply circuit according to claim 1, characterized in that: If it is detected that the gain trend of the switching power supply circuit changes, before controlling the upper switch tube and the lower switch tube in a complementary width modulation manner, the method further includes: Within a preset time period, the symmetrical bandwidth modulation mode is gradually adjusted to the complementary bandwidth modulation mode.

3. The control method of the switching power supply circuit according to claim 2, characterized in that: The step of gradually adjusting the symmetrical bandwidth modulation mode to the complementary bandwidth modulation mode within a preset time period includes: Keeping the control mode of the first switch unchanged, controlling the duty cycle of the second switch to gradually increase until the first switch and the second switch are complementarily turned on outside the preset dead time; The first switch tube is one of the upper switch tube and the lower switch tube, and the second switch tube is the other of the upper switch tube and the lower switch tube.

4. The control method of the switching power supply circuit according to claim 3, characterized in that: The step of controlling the duty cycle of the second switch tube to gradually increase includes: According to the preset step size, the duty cycle of the second switch tube is controlled to increase linearly.

5. The control method of the switching power supply circuit according to any one of claims 1 to 4, characterized in that: The detecting that a gain trend of the switching power supply circuit changes includes: The duty cycle maintains an increasing or decreasing direction unchanged. If it is detected that the detection parameter of the switching power supply circuit changes from an upward trend to a downward trend or from a downward trend to an upward trend, it is determined that the gain trend of the switching power supply circuit has changed, wherein the detection parameter includes the gain or the output voltage or the output current.

6. The control method of a switching power supply circuit according to any one of claims 1 to 4, characterized in that: The resonant circuit includes parasitic capacitance and / or parasitic inductance of the switching power supply circuit.

7. The control method of a switching power supply circuit according to any one of claims 1 to 4, characterized in that: The control method of the switching power supply circuit further includes: In the process of controlling the upper switch tube and the lower switch tube in a symmetrical width modulation manner, if it is detected that the duty cycle of each switch tube of the switching power supply circuit is less than a preset minimum duty cycle, the upper switch tube and the lower switch tube are controlled in a complementary width modulation manner.

8. A controller, characterized in that: The invention comprises a memory and a processor, wherein the memory is used to store a computer program, and the processor is used to call and run the computer program stored in the memory to execute the control method of the switching power supply circuit according to any one of claims 1 to 7.

9. A switching power supply circuit, characterized in that: The controller comprises the controller as claimed in claim 8 and an upper switch tube and a lower switch tube that cannot be turned on at the same time; the switching power supply circuit has a resonant circuit; The upper switch tube and the lower switch tube are controlled by the controller.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method for controlling a switching power supply circuit according to any one of claims 1 to 7 are implemented.

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