Control method, controller, switching power supply and device of half-bridge LLC resonant circuit

Abstract

The present invention discloses a control method, a controller, a switching power supply and an electronic device for a half-bridge LLC resonant circuit. The control method comprises: detecting and judging the output power; when the output power is less than a preset first power threshold value P1 and greater than a preset second power threshold value P2, entering a first skip cycle working mode; when the output power is less than a second power threshold value P2 and greater than a preset third power threshold value P3, entering a second skip cycle working mode, and P1>P2>P3. Through the combination of the two skip cycle working modes, the half-bridge LLC resonant circuit can reduce the equivalent switching frequency under light load as the output power decreases, thereby achieving the purpose of improving efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of power supply, and in particular to a control method, a controller, a switching power supply and a device for a half-bridge LLC resonant circuit. Background Art

[0002] In switching power supply applications, the half-bridge LLC resonant circuit is widely used in consumer electronics, industry, communications and other fields due to its excellent soft switching, EMI, high efficiency and high power density. However, for the half-bridge LLC resonant circuit, the switching frequency increases as the load decreases. When the load is reduced to a certain level, the switching frequency increases significantly, and the switching loss increases significantly, resulting in low efficiency of the half-bridge LLC resonant circuit when the load is light. Summary of the invention

[0003] The main technical problem solved by the present invention is to provide a control method, a controller, a switching power supply and a device for a half-bridge LLC resonant circuit, so as to solve the problem that the switching loss of the half-bridge LLC resonant circuit is difficult to reduce and the efficiency improvement is limited under light load.

[0004] In order to solve the above technical problems, a technical solution adopted by the present invention is to provide a control method for a half-bridge LLC resonant circuit, wherein the half-bridge LLC resonant circuit includes an upper switch tube, a lower switch tube, a resonant inductor, an exciting inductor and a resonant capacitor, and includes: detecting and judging the output power; when the output power is less than a preset first power threshold P1 and greater than a preset second power threshold P2, entering a first skip cycle working mode, wherein the first skip cycle working mode includes a first cycle, the first cycle includes a first duration and a second duration, in the first duration, the upper switch tube and the lower switch tube are alternately turned on, in the second duration, the upper switch tube and the lower switch tube are turned off at the same time, and the second duration is determined by automatically adjusting the number of oscillation cycles of the midpoint of the half bridge; when the output power is less than the second power threshold P2 and greater than a preset third power threshold P3, entering a second skip cycle working mode, wherein the second skip cycle working mode includes a second cycle, the second cycle is determined according to a preset output power-second cycle frequency curve, and P1>P2>P3.

[0005] Preferably, the method for detecting and judging the output power includes:

[0006] The optocoupler current is obtained through an optocoupler current sampling circuit, wherein the optocoupler current sampling circuit is electrically connected to the output end of the half-bridge LLC resonant circuit; the magnitude of the output power is determined by the optocoupler current, wherein the optocoupler current is linearly related to the output power.

[0007] Preferably, the first duration is determined according to a preset output power-switching frequency curve or an output power-resonant capacitor voltage change curve, and the number of times the upper tube and the lower tube are turned on and off in the first duration is preset.

[0008] Preferably, the method for determining the second time duration by automatically adjusting the number of oscillation cycles of the midpoint of the half-bridge specifically includes: obtaining an initial second time duration, wherein an initial value of the number of oscillation cycles included in the initial second time duration is preset; obtaining an optocoupler current used to characterize the output power; and increasing or decreasing the number of oscillation cycles according to the optocoupler current.

[0009] Preferably, the step of increasing or decreasing the number of oscillation cycles according to the optocoupler current specifically includes: when the optocoupler current is greater than a preset first current threshold, the number of oscillation cycles is increased by i to increase the second time length; when the optocoupler current is less than a preset second current threshold, the number of oscillation cycles is reduced by j to reduce the second time length; wherein i and j are positive integers, and the first current threshold is greater than the second current threshold.

[0010] Preferably, after the initial value of the number of oscillation cycles is changed, the half-bridge LLC resonant circuit is in a stable working state after a dynamic time, and thereafter the number of oscillation cycles may be increased or decreased again.

[0011] Preferably, the second cycle includes a third duration and a fourth duration, the third duration is determined according to a preset output power-switching frequency curve or an output power-resonant capacitor voltage change curve, and the number of times the upper tube and the lower tube are turned on and off in the third duration is pre-set.

[0012] Preferably, the first power threshold P1 is 15%-40% of the rated load power, the second power threshold P2 is 10%-25% of the rated load power, and the third power threshold P3 is 5%-20% of the rated load power.

[0013] Preferably, in the first jump cycle working mode, the switching frequency of the switching component composed of the upper switch tube and the lower switch tube has a frequency jump at least at one power point, and between two adjacent output powers where the frequency jump occurs, the switching frequency increases linearly as the output power decreases.

[0014] Preferably, in the second skip cycle working mode, the switching frequency of the switch assembly composed of the upper switch tube and the lower switch tube increases linearly as the output power decreases.

[0015] Preferably, the skip cycle frequency corresponding to the third power threshold P3 is greater than or equal to 20 kHz. Another embodiment of the present invention provides a controller for a half-bridge LLC resonant circuit, comprising:

[0016] A detection and judgment module, which is used to detect and judge the output power; and a first jump cycle control module, which is used to enter the first jump cycle working mode when the output power is less than a preset first power threshold P1 and greater than a preset second power threshold P2, wherein the first jump cycle working mode includes a first period, the first period includes a first duration and a second duration, in the first duration, the upper switch tube and the lower switch tube are alternately turned on, in the second duration, the upper switch tube and the lower switch tube are turned off at the same time, and the second duration is determined by automatically adjusting the number of oscillation periods of the midpoint of the half bridge; a second jump cycle control module, which is used to enter the second jump cycle working mode when the output power is less than the second power threshold P2 and greater than the preset third power threshold P3, wherein the second jump cycle working mode includes a second period, the second period is determined according to a preset output power-second period frequency curve, and P1>P2>P3.

[0017] Preferably, the first jump cycle control module also includes a second time length preset unit, an optocoupler current acquisition unit and an oscillation period adjustment unit, wherein the second time length preset unit is used to obtain an initial second time length, wherein the initial value of the number of oscillation periods included in the initial second time length is preset; the optocoupler current acquisition unit is used to obtain an optocoupler current used to characterize the output power; and the oscillation period adjustment unit is used to increase or decrease the number of oscillation periods according to the optocoupler current.

[0018] Preferably, the oscillation period adjustment unit also includes a first oscillation period adjustment unit and a second oscillation period adjustment unit, the first oscillation period adjustment unit being used to increase the number of oscillation periods by i so as to increase the second duration when the optocoupler current is greater than a preset first current threshold; the second oscillation period adjustment unit being used to reduce the number of oscillation periods by j so as to reduce the second duration when the optocoupler current is less than a preset second current threshold; wherein i and j are positive integers, and the first current threshold is greater than the second current threshold.

[0019] Another embodiment of the present invention provides a switching power supply, including a half-bridge LLC resonant circuit, and also includes a controller of the aforementioned half-bridge LLC resonant circuit, wherein the controller is electrically connected to the half-bridge LLC resonant circuit.

[0020] Another embodiment of the present invention provides an electronic device, including the controller of the aforementioned half-bridge LLC resonant circuit or the aforementioned switching power supply.

[0021] The beneficial effects of the present invention are as follows: the present invention discloses a control method, a controller, a switching power supply and a device for a half-bridge LLC resonant circuit, the control method comprising: detecting and judging the output power; when the output power is less than a preset first power threshold value P1 and greater than a preset second power threshold value P2, entering a first skip cycle working mode, and when the output power is less than a second power threshold value P2 and greater than a preset third power threshold value P3, entering a second skip cycle working mode, and P1>P2>P3. Through the combination of the two skip cycle working modes, the half-bridge LLC resonant circuit can reduce the equivalent switching frequency under light load as the output power decreases, thereby achieving the purpose of improving efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a typical circuit diagram of the switching power supply of the present invention;

[0023] Figure 2 is a method flow chart of an embodiment of a control method of a half-bridge LLC resonant circuit according to the present invention;

[0024] Figure 3 is a flowchart of a skip cycle working mode in an embodiment of a control method for a half-bridge LLC resonant circuit according to the present invention;

[0025] Figure 4 is a switching signal waveform diagram of the half-bridge LLC resonant circuit of the present invention in a continuous working mode;

[0026] Figure 5 It is a characteristic curve diagram of output power and optocoupler current of the half-bridge LLC resonant circuit of the present invention in different working modes;

[0027] Figure 6 is a characteristic curve diagram of output power and switching frequency of the half-bridge LLC resonant circuit of the present invention in different working modes;

[0028] Figure 7 It is a switching signal waveform diagram of the half-bridge LLC resonant circuit of the present invention in a skip cycle working mode;

[0029] Figure 8 Yes means Figure 7 The diagram of the adjustment mechanism of the number of oscillation cycles of the half-bridge midpoint Z of the second duration of the half-bridge LLC resonant circuit in the skip cycle working mode is shown;

[0030] Fig. 9 Yes means Figure 7 The curve characteristic diagram of the output power of the first cycle and the first cycle frequency of the half-bridge LLC resonant circuit shown in the first skip cycle working mode;

[0031] Fig.10 Yes means Figure 7 The characteristic curve diagram of the optocoupler current of the fourth time length and the second cycle frequency of the half-bridge LLC resonant circuit in the skip cycle working mode shown;

[0032] Fig.11 Yes means Figure 7 A curve characteristic diagram of the output power of the second cycle and the frequency of the second cycle of the half-bridge LLC resonant circuit in the second skip cycle working mode;

[0033] Fig.12 is a switching signal waveform diagram of the half-bridge LLC resonant circuit of the present invention in the hiccup working mode;

[0034] Fig.13 is a characteristic curve diagram of another embodiment of the half-bridge LLC resonant circuit of the present invention under different operating modes;

[0035] Fig.14 is a schematic diagram of the logical structure of a control device provided by an embodiment of the present invention;

[0036] Fig.15 It is a schematic diagram of the logical structure of a controller provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0038] The terms "including" and "having" and any variations thereof appearing in the specification, claims and drawings of this application are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device comprising a series of steps or modules is not limited to the listed steps or units, but may optionally include steps or units that are not listed, or may optionally include other steps or units that are inherent to these processes, methods, products or devices. In addition, the terms "first", "second" and "third" are used to distinguish different objects, rather than to describe a specific order.

[0039] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0040] like Figure 1As shown, the switching power supply includes a half-bridge LLC resonant circuit 100, and the half-bridge LLC resonant circuit 100 includes an upper switch tube (referred to as "upper tube" in this patent) HG and a lower switch tube (referred to as "lower tube" in this patent) LG, and the upper tube HG and the lower tube LG are preferably MOS tubes. The half-bridge LLC resonant circuit 100 also includes two inductors and a resonant capacitor Cr, and the two inductors are respectively a resonant inductor Lr and an exciting inductor Lm. The resonant inductor Lr, the exciting inductor Lm, and the resonant capacitor Cr form a resonant network, and the resonant capacitor Cr acts as a DC isolation capacitor, while balancing the transformer flux to prevent saturation. Among them, the half-bridge LLC resonant circuit forms two resonant frequencies fr1 and fr2, wherein the resonant frequency fr1 is the resonant frequency of the resonant inductor Lr and the resonant capacitor Cr, and the resonant frequency fr2 is the resonant frequency of the resonant inductor Lr, the resonant capacitor Cr, and the exciting inductor Lm.

[0041] The half-bridge LLC resonant circuit 100 is an inverter bridge composed of a high-frequency switching network, which can invert the input DC voltage into an AC square wave voltage with a duty cycle of 50% and a switching frequency fsw; then the square wave voltage and the resonant current Ir at the midpoint Z of the half-bridge are input into the resonant network, and the harmonic components that deviate from the resonant frequency fr1 or the resonant frequency fr2 are filtered. The rectifier network on the secondary side of the transformer is composed of a rectifier diode or other rectifier components. The fundamental wave component of the resonant output is rectified to an approximate DC voltage through high-frequency rectification, and finally filtered through a low-pass filter at the output end to obtain the voltage of the DC component. The switching power supply also includes an optocoupler current sampling circuit (not shown in the figure), which is electrically connected to the output end of the half-bridge LLC resonant circuit 100, and the optocoupler current Iopto is obtained through the optocoupler current sampling circuit. The size of the output power P is judged by the optocoupler current Iopto, and the optocoupler current Iopto is linearly related to the output power P. The working state of the load end LOAD can be determined according to the output power P. The half-bridge LLC resonant circuit is set in a continuous working mode, a skipping working mode or a hiccup working mode according to the working state of the load end LOAD, thereby adjusting the equivalent switching frequency and reducing the switching loss.

[0042] The switching power supply also includes a controller of a half-bridge LLC resonant circuit, which is electrically connected to the half-bridge LLC resonant circuit. The controller is used to control the half-bridge LLC resonant circuit, specifically to control the on and off of the upper tube HG and the lower tube LG. The controller of the half-bridge LLC resonant circuit is also electrically connected to the optocoupler current sampling circuit to receive the optocoupler current Iopto.

[0043] Specifically, see Figure 1 , Figure 2 as well as Figure 3 , Figure 2The method flow chart of a control method for a half-bridge LLC resonant circuit according to an embodiment of the present invention is shown. Figure 3 The work flow chart of the skip cycle operation mode of a control method for a half-bridge LLC resonant circuit according to an embodiment of the present invention is shown.

[0044] As Figure 2 shown, step S201 is executed to detect the output power P of the half-bridge LLC resonant circuit 100 output to the load end LOAD. Step S202 is executed to compare the output power P of the half-bridge LLC resonant circuit 100 output to the load end LOAD with a preset first power threshold P1, a second power threshold P2, and a third power threshold P3, and P3 < P2 < P1. Preferably, the first power threshold P1 is 15% - 40% of the rated load power, preferably 25%, 30%, etc.; the second power threshold P2 is 10% - 25% of the rated load power, preferably 15%, 20%, etc., and the third power threshold P3 is 5% - 20% of the rated load power, preferably 10%. According to the comparison result, it is judged which operation mode the half-bridge LLC resonant circuit 100 enters.

[0045] Next, step S203 is executed to judge whether the output power P is greater than the first power threshold P1:

[0046] When the output power P is greater than the first power threshold P1, the working state of the load end LOAD is a heavy load state. Step S204 is executed to set the half-bridge LLC resonant circuit 100 in a continuous operation mode. In the continuous operation mode, the upper transistor HG and the lower transistor LG of the half-bridge LLC resonant circuit 100 are continuously and alternately turned on. The input end Vin of the half-bridge LLC resonant circuit 100 is connected to the power supply, and the current is output after passing through the continuously and alternately turned-on upper transistor HG and lower transistor LG. The upper transistor HG and the lower transistor LG are controlled by the switching signals HG1 and LG1 output by the controller. Please refer to Figure 4 , Figure 4 is the waveform diagram of the switching signals generated by the continuous and alternate conduction of the upper transistor HG and the lower transistor LG when the half-bridge LLC resonant circuit 100 is in the continuous operation mode. The switching signals HG1 and LG1 include a plurality of continuous periodic pulses. The period of the switching signals HG1 and LG1 is determined by the switching frequency fsw. The higher the switching frequency fsw, the shorter the period. As the upper transistor HG and the lower transistor LG are continuously and alternately turned on, the resonant current Ir1 is a continuous sine wave.

[0047] In the continuous operation mode, that is, in the range where the output power P is greater than the first power threshold P1, as the output power P decreases, the output optocoupler current Iopto increases as the output power P decreases, as Figure 5 shown, Figure 5is a characteristic curve diagram of the output power P and the optocoupler current Iopto of the half-bridge LLC resonant circuit 100 in different working modes; the switching frequency fsw increases as the output power P decreases, such as Figure 6 As shown, Figure 6 is a characteristic curve diagram of the output power P and the switching frequency fsw of the half-bridge LLC resonant circuit 100 in different working modes.

[0048] It can be seen that when the output power P is greater than the first power threshold P1, the switching frequency fsw and the optocoupler current Iopto are linearly related. As the output power P decreases, the optocoupler current Iopto gradually increases, and the switching frequency fsw also gradually increases. In this working mode, as the output power P decreases, when the load end LOAD is in a light load state, the switching loss is large and the efficiency is poor.

[0049] Therefore, when the output power P is lower than the first power threshold P1, in order to improve the efficiency of light load, the half-bridge LLC resonant circuit enters the skip cycle working mode, specifically:

[0050] Execute step S205 to determine whether the output power P is greater than the third power threshold value P3. When the output power P is greater than the third power threshold value P3, the working state of the load end LOAD is a general load state, and execute step S206 to set the half-bridge LLC resonant circuit 100 to a skip cycle working mode. In the skip cycle working mode, after the upper tube HG and the lower tube LG of the half-bridge LLC resonant circuit 100 are alternately turned on for a first time period T1, the upper tube HG and the lower tube LG are simultaneously turned off for a second time period T2. The input terminal Vin of the half-bridge LLC resonant circuit 100 is connected to the power supply, and the current is output after passing through the upper tube HG and the lower tube LG that are continuously and alternately turned on. The upper tube HG and the lower tube LG are controlled by the switching signals HG2 and LG2 output by the controller, please refer to Figure 7 , Figure 7 The waveform diagram of the switching signal generated when the half-bridge LLC resonant circuit 100 is in the skip cycle working mode, the upper tube HG and the lower tube LG are first alternately turned on and then turned off at the same time. The switching signals HG2 and LG2 include multiple periodic pulses in the first time length T1, and there is no pulse signal in the second time length T2. As the upper tube HG and the lower tube LG are alternately turned on for the first time length T1 and then turned off for the second time length T2, the resonant current Ir2 changes with the switching signal. In one embodiment of the present application, in the first time length T1, the upper tube HG is preset to be turned on and turned on twice, and the lower tube LG is preset to be turned on and turned on twice (the time of the first turn-on + the time of the third turn-on = the time of the second turn-on in the figure), forming two cycles. The ratio of the time when the upper tube is turned on to the time when the lower tube is turned on in each cycle is preset and determined. Figure 7The ratio is 1:1, that is, the conduction time of the upper transistor is equal to the conduction time of the lower transistor in one cycle. Of course, the ratio can also be set to other ratios according to actual needs. In this embodiment, the number of times the upper transistor conducts and turns off, and the number of times the lower transistor conducts and turns off can also be preset to other numbers, but the conduction duration is not preset, and how to adjust it will be described later. Subsequently, the upper transistor HG and the lower transistor LG are simultaneously turned off for a second duration T2. The first duration and the second duration constitute one cycle, and then the upper transistor HG and the lower transistor LG repeat the previous cycle. The starting point of one cycle is when the switching signal LG2 becomes high level, at this time the voltage Vz at the midpoint Z of the half-bridge drops to low level. Next, both the switching signals HG2 and LG2 are low level, at this time the voltage Vz at the midpoint Z of the half-bridge rises to high level. Then the switching signal HG2 is high level, and the voltage Vz at the midpoint Z of the half-bridge maintains high level. Subsequently, both the switching signals HG2 and LG2 are low level, and the voltage Vz at the midpoint Z of the half-bridge drops to low level. Subsequently, when both the upper transistor HG and the lower transistor LG are turned off and both the switching signals HG2 and LG2 are low level, at this time, the voltage Vz at the midpoint Z of the half-bridge starts to oscillate, and the duration of each oscillation cycle is the same, which is t.

[0051] When step S206 is executed, as Figure 3 shown, when the half-bridge LLC resonant circuit 100 is set to the skip-cycle operation mode, that is, the output power P is less than the first power threshold P1 and greater than the third power threshold P3, step S208 is executed to compare the output power P with the second power threshold P2 to determine the size, and according to the comparison result, it is judged which skip-cycle operation mode the half-bridge LLC resonant circuit 100 is set to. Step S209 is executed to judge whether the output power P is greater than the second power threshold P2. When the output power P is greater than the second power threshold P2, step S210 is executed to control the half-bridge LLC resonant circuit 100 to operate in the first skip-cycle operation mode; when the output power is less than the second power threshold P2, step S211 is executed to control the half-bridge LLC resonant circuit 100 to operate in the second skip-cycle operation mode.

[0052] When the half-bridge LLC resonant circuit 100 operates in the first skip-cycle operation mode, that is, P2 < P < P1. The first skip-cycle operation mode includes a first cycle, and the first cycle includes a first duration T1 and a second duration T2. In this mode, the upper transistor HG and the lower transistor LG alternately conduct for the first duration T1. In an embodiment of the present application, the first duration T1 is based on a preset output power-switching frequency curve (please refer to Figure 6 ) or an output power-resonant capacitor voltage change curve (please refer to Fig.13Determined by the middle figure), when the power is determined, the switching frequency or the change amount of the resonant capacitor voltage is determined. Furthermore, the duration (conduction) of the high level of the upper switch HG and the lower switch LG can be determined. In this embodiment, the duration of the high level of the upper switch HG and the lower switch LG in one cycle is equal. Since the number of times the upper switch HG and the lower switch LG are turned on and off is preset and the duration of the high level is determined, the first duration can be determined. Combining with adjusting the second duration T2 when the upper switch HG and the lower switch LG are turned off simultaneously, the first cycle frequency can be regulated. The first cycle frequency is the reciprocal of the first cycle, and the second duration T2 when the upper switch HG and the lower switch LG are turned off simultaneously is determined by automatically adjusting the number of oscillation cycles at the midpoint Z of the half-bridge. Specifically:

[0053] First, obtain the initial second duration. Among them, the initial value of the number of oscillation cycles included in the initial second duration is N, and N is a positive integer. Further, those skilled in the art can set the initial value of the number of oscillation cycles according to actual needs.

[0054] Secondly, obtain the optocoupler current Iopto for characterizing the output power P, and determine whether the number of oscillation cycles increases or decreases according to the optocoupler current Iopto. Specifically, compare the obtained optocoupler current Iopto with a preset first current threshold Iopto1 and a second current threshold Iopto2, and the first current threshold Iopto1 is greater than the second current threshold Iopto2. When P2 < P < P1, the optocoupler current Iopto changes within the range of the first current threshold Iopto1 and the second current threshold Iopto2. At this time, there is no need to adjust the number of oscillation cycles. Please refer to Figure 5 and Figure 8 , Figure 8The diagram shows the adjustment mechanism of the number of oscillation cycles of the half-bridge midpoint Z of the half-bridge LLC resonant circuit in the first jump cycle working mode; when the optocoupler current value Iopto is greater than the first current threshold value Iopto1, it means that the output power P is low, then the initial value N of the number of oscillation cycles increases by i to obtain the first number of oscillation cycles N+i, where i is a positive integer, for example, i is 1, then the initial second duration increases by i*t (as mentioned above, t represents the duration of the oscillation cycle), that is, the simultaneous shutdown time of the upper tube HG and the lower tube LG increases by i*t. When the simultaneous shutdown time of the upper tube HG and the lower tube LG increases by i*t, the first cycle will also increase accordingly, and the first duration T1 has been determined, therefore, the number of upper tubes HG and lower tubes LG that are turned on in a unit time is reduced, and the power remains unchanged, so that the energy of the upper tube HG and the lower tube LG that are turned on in the first duration will become larger, which can reduce the equivalent switching frequency and achieve the purpose of improving efficiency, and thereafter the optocoupler current Iopto will decrease. When the optocoupler current Iopto is less than the second current threshold Iopto2, it means that the output power P is higher, then the initial value N of the number of oscillation cycles is reduced by j to obtain the second number of oscillation cycles Nj, where j is a positive integer, for example, j is 1, and the initial second duration is reduced by j*t, that is, the time when the upper tube HG and the lower tube LG are turned off at the same time is reduced by j*t. When the time when the upper tube HG and the lower tube LG are turned off at the same time is reduced by j*t, the number of upper tubes HG and lower tubes LG that are turned on per unit time increases, and the power remains unchanged, so that the energy of the conductive part of the upper tube HG and the lower tube LG in the first duration will become smaller, and the equivalent switching frequency can be increased. By increasing the equivalent switching frequency, the optocoupler current Iopto will increase. This cycle is repeated until the optocoupler current Iopto is between the second current threshold Iopto2 and the first current threshold Iopto1. In this embodiment, the switching frequency is defined as: the number of times the upper tube HG and the lower tube LG are turned on once in the first duration T1 or the third duration T3, Figure 7 The number of conducting diodes is 2, and then the number is divided by the first duration to get the switching frequency. The equivalent switching frequency is defined as the number divided by the first period or the second period. In the continuous operation mode, the second and fourth durations are 0.

[0055] After each change in the number of oscillation cycles, the half-bridge LLC resonant circuit will have a dynamic time tdynamic for stabilizing the working state. After this time, it will be in a stable working state, and then the number of oscillation cycles can be adjusted again. In the first jump cycle working mode, each jump cycle can achieve ZVS (zero voltage switching), and the method locks the number of oscillation cycles, and the first cycle frequency is stable greater than or equal to 20KHz, preferably greater than 25KHz, to avoid audio noise.

[0056] When the number of oscillation cycles changes, at the jump point where the optocoupler current Iopto increases or decreases, the corresponding first cycle frequency will also jump. That is, when the half-bridge LLC resonant circuit is in a stable working state, that is, the optocoupler current Iopto is less than the first current threshold Iopto1 and greater than the second current threshold Iopto2, as the output power P decreases, the optocoupler current Iopto and the first cycle frequency both increase linearly with the decrease in output power, but when the optocoupler current Iopto is greater than the first current threshold Iopto1, the optocoupler current Iopto and the first cycle frequency both jump and decrease for every i increase in the number of oscillation cycles. Specifically, the curve characteristic diagram of the optocoupler current Iopto and the first cycle frequency changing with the output power is shown in the figure. Figure 5 and Fig. 9 As shown, when the number of oscillation cycles increases by i, the optocoupler current Iopto decreases to the second current threshold Iopto2, and then the optocoupler current Iopto increases linearly with the decrease of the output power P, and the corresponding first cycle frequency also increases linearly with the decrease of the output power P. Fig. 9 As shown in FIG. 1 , at the first output power P11 and the second output power P12, the jump point where the number of oscillation cycles increases and causes the first cycle frequency to decrease, after the first cycle frequency decreases to a certain value, when the half-bridge LLC resonant circuit is in a stable working state, the first cycle frequency increases linearly with the decrease of the output power P. However, the rate of each linear increase of the first cycle frequency F gradually decreases. Therefore, in the entire second time interval T2, the first cycle frequency F decreases with the decrease of the output power P, from Fig. 9 It can be seen that the first cycle frequency F varies within the first cycle maximum frequency F1 and the first cycle minimum frequency F2, indicating that as the output power P decreases, the first cycle frequency is effectively controlled within a range, which effectively reduces the equivalent switching frequency and reduces the loss caused by excessive switching frequency.

[0057] When the output power is further reduced, the number of oscillation cycles increases by n, and the number of oscillation cycles is N+n. If n is large enough, the speed at which the equivalent switching frequency decreases will become slower. Please refer to Figure 6, in the first-hop cycle operating mode, when the number of oscillation cycles gradually increases, the rate of decrease in the equivalent switching frequency will also gradually decrease. As the power continues to decrease, the curve of the equivalent switching frequency will deviate from the optimal curve (generally, the optimal curve changes relatively slowly between output powers P1 - P2 and changes relatively steeply between output powers P2 - P3), resulting in the increase in the number of oscillation cycles having less significant impact on the equivalent switching frequency, making it difficult to reduce the switching loss and achieve the purpose of improving efficiency. Moreover, the oscillation energy will decrease, and it will be difficult to identify the number of oscillation cycles later. For these reasons, when the output power P is lower than the second power threshold P2, the half-bridge LLC resonant controller controls the half-bridge LLC resonant circuit 100 to enter the second-hop cycle operating mode.

[0058] When P3 < P < P2, the half-bridge LLC resonant circuit enters the second-hop cycle operating mode. The second-hop cycle operating mode includes a second cycle, and the second cycle is determined according to a preset output power - second cycle frequency curve ( Fig.10 ), and P1 > P2 > P3. When the power is determined, the second cycle frequency fskip can be obtained according to the curve and determined, and thus the second cycle is determined.

[0059] In this embodiment, the second cycle includes a third duration T3 and a fourth duration T4. The third duration T3 is determined according to a preset output power - switching frequency curve ( Figure 6 ) or an output power - resonant capacitor voltage change curve ( Fig.13 in the figure), and the number of times the upper transistor HG and the lower transistor LG are turned on and off during the third duration is preset. In this embodiment, the number of times the upper transistor HG and the lower transistor LG are turned on and off is preset to 2 times and 3 times. At the same time, the lower transistor LG being turned on 3 times includes 1 complete duration and two half durations, constituting two complete conduction durations. In this embodiment, when the power is determined, the switching frequency or the resonant capacitor voltage change amount is determined, and then the duration (conduction) of the upper transistor HG and the lower transistor LG being at a high level can be determined. In this embodiment, the durations of the upper transistor HG and the lower transistor LG being at a high level are equal. Since the number of times the upper transistor HG and the lower transistor LG are turned on and off is preset and the duration of the high level is determined, the third duration can be determined, and then the fourth duration can be obtained by subtracting the third duration from the second cycle.

[0060] In this embodiment, the number of oscillation cycles included in the fourth duration T4 is calculated and determined according to the above method. Fig.10 The figure shows the curve characteristic diagram of the optocoupler current Iopto and the second cycle frequency fskip of the half-bridge LLC resonant circuit in the second-hop cycle operating mode. Here, the second cycle frequency fskip corresponds to the second cycle and is the reciprocal of the second cycle. In this embodiment, please refer to Fig.10, the curve of the optocoupler current Iopto and the second cycle frequency fskip is a slant line, the optocoupler current has two endpoint values, the third current threshold Iopto3 and the fourth current threshold Iopto4, and the third current threshold Iopto3 is less than the fourth current threshold Iopto4, the third current threshold Iopto3 is greater than the first current threshold Iopto1, wherein the third current threshold Iopto3 defines the maximum value fskip1 of the second cycle frequency fskip, in this embodiment, the third current threshold Iopto3 is the switching point between the first skip cycle working mode and the second skip cycle working mode, and the corresponding output power P is the second power threshold P2. In other embodiments of the present application, the maximum value fskip1 of the second cycle frequency fskip can be set according to the output power of the half-bridge LLC resonant circuit. In other embodiments, the switching point between the first skip cycle working mode and the second skip cycle working mode can be less than the third current threshold Iopto3. The fourth current threshold Iopto4 limits the minimum value fskip2 of the second cycle frequency fskip. The minimum value fskip2 is greater than or equal to 20kHz, preferably greater than or equal to 25kHz. Thus, the optimal second cycle frequency fskip curve is determined by the optocoupler current Iopto. When the output power decreases, the optocoupler current Iopto increases, and the second cycle frequency fskip decreases as the optocoupler current Iopto increases, and the result is Fig.10 .from Figure 5 It can be seen that when the output power P is greater than the third power threshold P3 and less than the second power threshold P2, the optocoupler current Iopto is linearly related to the output power P. Therefore, the second cycle frequency fskip also decreases as the output power P decreases, and the result is Fig.11 In the second skip cycle working mode, as the output power P decreases, the second cycle frequency fskip decreases, that is, the second cycle increases, and the third time length T3 has been determined, so the fourth time length T4 increases, and the number of oscillation cycles corresponding to the fourth time length T4 also increases according to the increased time length, thereby achieving the purpose of reducing the equivalent switching frequency and improving efficiency.

[0061] The second hopping period working mode adjusts the equivalent switching frequency by adjusting the duration of the second period. The optimal time adjustment point is to achieve ZVS at the valley of the oscillation period. When the change in time is in front of the valley of the oscillation period (the fourth duration), it is necessary to wait for a period of time to reach the valley before ZVS can be achieved during the oscillation period; when the change in time is behind the valley of the oscillation period, it is necessary to wait for the valley of the next oscillation period to achieve ZVS. The change in the number of oscillation periods causes the second period frequency to change violently. When the output power is relatively high, the violent change in the second period frequency will cause relatively serious audio noise. When the power is relatively low, audio noise can be effectively avoided. Therefore, when the output power is between the first power threshold P1 and the third power threshold P3, the efficiency can be effectively improved by combining the first hopping period working mode and the second hopping period working mode.

[0062] In this embodiment, please refer to Figure 6 , the preset output power-switching frequency curve in the second hopping period mode is a straight line (i.e., in the interval P3 < P < P2). In the first hopping period working mode, when the number of oscillation periods is determined, its actual output power-switching frequency curve is also a straight line ( Figure 6 shows three straight lines, each corresponding to a different number of oscillation periods), and the slope of the preset output power-switching frequency curve in the second hopping period mode is greater than the slope of the actual output power-switching frequency curve in the first hopping period mode, that is, the output power-switching frequency curve in the second hopping period mode is steeper. Thus, in this embodiment, by combining the first hopping period working mode and the second hopping period working mode, the actual output power-switching frequency curve can be made closer to the optimal curve when the output power is between P1 - P3.

[0063] The adjustment steps of the first hopping period working mode are finally as follows: when the load changes, the corresponding output power also changes. The controller adjusts the switching frequency according to the optocoupler current Iopto. The switching frequency is one cycle formed by the upper transistor HG conducting once and the lower transistor LG conducting once ( Figure 7 shows two cycles, the number is preset, and the conduction duration is adjustable). The reciprocal of this cycle is the switching frequency. The switching frequency has a maximum value and a minimum value. When the switching frequency is adjusted to the maximum value or the minimum value and the desired output power P has not been reached (at this time, the optocoupler current Iopto must be greater than Iopto1 or less than Iopto2), then the controller controls the adjustment of the number of oscillation periods included in the second duration T2, and repeatedly adjusts until the optocoupler current Iopto is between the first current threshold Iopto1 and the second current threshold Iopto2. At this time, the switching frequency is between the maximum value and the minimum value, and then the switching frequency is adjusted again ( Figure 6After repeated adjustments, the desired output power P is finally achieved, wherein the first duration T1 and the second duration T2 can be adjusted simultaneously or one after the other.

[0064] The adjustment steps of the second jump cycle working mode are finally as follows: when the load changes, the corresponding output power P also needs to change. The second cycle frequency is determined according to the preset output power-second cycle frequency curve, and then the second cycle is obtained. At the same time, the switching frequency can be obtained according to the preset output power-switching frequency curve, and then the conduction time is obtained, so that the third time length T3 can be obtained. After the third time length T3 is obtained, the fourth time length T4 can be obtained according to calculation.

[0065] As the output power P decreases, when the output power P is less than the third power threshold P3, the working state of the load terminal LOAD is a light load or zero load state, and step S207 is executed to control the half-bridge LLC resonant circuit 100 to work in the hiccup working mode. Fig.12 In the hiccup working mode, after the upper tube HG and the lower tube LG of the half-bridge LLC resonant circuit 100 are alternately turned on for the fifth time period T5 (including being turned off at the same time for a relatively short period of time), the upper tube HG and the lower tube LG are turned off at the same time for the sixth time period T6, and the fifth time period T5 during which the upper tube HG and the lower tube LG are alternately turned on is significantly shorter than the sixth time period T6 during which the upper tube HG and the lower tube LG are turned off at the same time. The input terminal Vin of the half-bridge LLC resonant circuit 100 is connected to the power supply, and the current is output after passing through the upper tube HG and the lower tube LG that are continuously and alternately turned on. The upper tube HG and the lower tube LG are controlled by the switch signals HG3 and LG3 output by the controller. Please continue to refer to Fig.12 , Fig.12 The figure is a switching signal waveform diagram generated when the upper tube HG and the lower tube LG are alternately turned on and then turned off simultaneously when the half-bridge LLC resonant circuit 100 is in the hiccup working mode. The switching signals HG3 and LG3 include multiple periodic pulses in the fifth time length T5, and there is no pulse signal in the sixth time length T6. As the upper tube HG and the lower tube LG are alternately turned on for the fifth time length T5 and then turned off for the sixth time length T6, the resonant current Ir3 changes with the switching signal.

[0066] In the hiccup mode, if Figure 5 , Figure 6 As shown, within the range where the output power P is less than the third power threshold P3, as the output power P decreases, the output optocoupler current Iopto does not change as the output power P decreases, and the switching frequency fsw does not change as the output power P decreases.

[0067] It can be seen that when the output power P is less than the third power threshold P3, the working state of the load end LOAD is in a light load or zero load state, the switching frequency fsw and the optocoupler current Iopto are maintained at a constant value, and no longer continue to gradually increase as the output power P decreases, that is, during the period when the upper tube HG and the lower tube LG of the half-bridge LLC resonant circuit 100 are turned off at the same time, the half-bridge LLC resonant circuit 100 operates in a low power consumption mode, and the circuit enters a sleep mode, which greatly reduces standby power consumption, reduces switching losses, and improves light load efficiency.

[0068] In another embodiment of the present invention, see Fig.13 The voltage variation on the resonant capacitor Cr can also be adjusted according to the output power P of the half-bridge LLC resonant circuit. This embodiment is similar to the previous embodiment, except that the controller in the previous embodiment adjusts the switching frequency fsw, while the controller in this embodiment adjusts the voltage variation on the resonant capacitor Cr. Fig.13 The curve in the middle figure can also reach Figure 6 The switching frequency of the curve.

[0069] When the output power P is greater than P1, the half-bridge LLC resonant circuit is in continuous working mode, the optocoupler current Iopto increases as the output power P decreases, the resonant capacitor Cr voltage change VCr decreases as the output power P decreases, and the switching frequency fsw (the switching frequency coincides with the first cycle frequency at this time) increases as the output power P decreases. It can be seen that the resonant capacitor Cr voltage change VCr is linearly correlated with the optocoupler current Iopto.

[0070] When the output power P is less than the first power threshold value P1 and greater than the second power threshold value P2, the half-bridge LLC resonant circuit operates in the first skip cycle working mode, the resonant capacitor Cr voltage change VCr decreases as the output power P decreases, and the resonant capacitor Cr voltage change VCr is linearly correlated with the optocoupler current Iopto. For the specific content of the first skip cycle working mode, please refer to the previous content description, which will not be repeated here; when the output power P is less than the second power threshold value P2 and greater than the third power threshold value P3, the half-bridge LLC resonant circuit operates in the second skip cycle working mode, the optocoupler current Iopto increases as the output power P decreases, and the resonant capacitor Cr voltage change VCr decreases as the output power P decreases. It can be seen that the resonant capacitor Cr voltage change VCr is linearly correlated with the optocoupler current Iopto, and the second cycle frequency fskip decreases as the output power P decreases. Therefore, the second cycle frequency F and the optocoupler current Iopto are also linearly related. In this embodiment, in the second jump cycle mode, the third duration is determined according to a preset output power-resonant capacitor voltage change curve. In this embodiment, the output power-resonant capacitor voltage change curve is a slant line. Similarly, in the first jump cycle working mode, after the number of oscillation cycles is determined, the output power-resonant capacitor voltage change actual curve is also a slant line ( Fig.13 In the figure, three oblique lines are shown, each of which corresponds to a different number of oscillation cycles), and the slope of the preset output power-resonant capacitor voltage change curve in the second jump cycle mode is greater than the slope of the actual output power-resonant capacitor voltage change curve in the first jump cycle mode, that is, the output power-resonant capacitor voltage change curve in the second jump cycle mode is steeper. When the output power P is less than the third power threshold value P3, the half-bridge LLC resonant circuit operates in the hiccup working mode, the load end LOAD is in a light load or no-load state, and the optocoupler current Iopto and the resonant capacitor Cr voltage change VCr remain unchanged.

[0071] In another embodiment of the present invention, a storage device stores a plurality of instructions, which are suitable for being loaded and executed by a processor. Figure 2 and Figure 3 For the instructions corresponding to the control method of the embodiment, the specific execution process and beneficial effects can be found in the aforementioned embodiment, which will not be elaborated here.

[0072] In another embodiment of the present invention, please refer to Fig.14 , the control equipment includes:

[0073] A processor 1401 adapted to implement each instruction; and

[0074] The storage device 1402 is adapted to store a plurality of instructions, and the instructions are adapted to be loaded and executed by the processor such as Figure 2 and Figure 3For the instructions corresponding to the control method of the embodiment, the specific execution process and beneficial effects can be found in the aforementioned embodiment, which will not be described in detail here.

[0075] An embodiment of the present invention provides a controller for a half-bridge LLC resonant circuit, see Fig.15 , the controller includes a detection and judgment module 1501, which is used to detect and judge the output power P; and

[0076] A first hopping cycle control module 1502, which is used to enter a first hopping cycle working mode when the output power P is less than a preset first power threshold P1 and greater than a preset second power threshold P2;

[0077] The second skip cycle control module 1503 is used to enter the second skip cycle working mode when the output power P is less than the second power threshold P2 and greater than the preset third power threshold P3. Please refer to the above embodiment for the specific execution process and beneficial effects, which will not be repeated here.

[0078] In this embodiment, the first jump cycle control module includes a second time length preset unit, an optocoupler current acquisition unit and an oscillation period adjustment unit, wherein the second time length preset unit is used to obtain an initial second time length, wherein the initial value of the number of oscillation periods included in the initial second time length is preset; the optocoupler current acquisition unit is used to obtain an optocoupler current used to characterize the output power; and the oscillation period adjustment unit is used to increase or decrease the number of oscillation periods according to the optocoupler current.

[0079] In this embodiment, the oscillation period adjustment unit also includes a first oscillation period adjustment unit and a second oscillation period adjustment unit. The first oscillation period adjustment unit is used to increase the number of oscillation periods by i so as to increase the second duration when the optocoupler current is greater than a preset first current threshold; the second oscillation period adjustment unit is used to reduce the number of oscillation periods by j so as to reduce the second duration when the optocoupler current is less than a preset second current threshold; wherein i and j are positive integers, and the first current threshold is greater than the second current threshold.

[0080] An embodiment of the present invention further provides a switching power supply, characterized in that it includes a half-bridge LLC resonant circuit and a controller of the above-mentioned half-bridge LLC resonant circuit, and the controller is electrically connected to the half-bridge LLC resonant circuit.

[0081] An embodiment of the present invention further provides an electronic device, including the controller of the half-bridge LLC resonant circuit or the switching power supply.

[0082] It should be understood that the "plurality" mentioned in this article refers to two or more. Those skilled in the art will easily think of other embodiments of the present application after considering the specification and practicing the application disclosed herein. The present application is intended to cover any modification, use or adaptation of the present application, which follows the general principles of the present application and includes common knowledge or customary technical means in the art that are not disclosed in the present application. The description and examples are only regarded as exemplary, and the true scope and spirit of the present application are indicated by the following claims.

[0083] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between the various embodiments can be referred to each other. For the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0084] The above disclosure is only the preferred embodiment of the present application, which certainly cannot be used to limit the scope of rights of the present application. Therefore, equivalent changes made according to the claims of the present application are still within the scope covered by the present application.

Claims

1. A control method for a half-bridge LLC resonant circuit, wherein the half-bridge LLC resonant circuit comprises an upper switch tube 、 Lower switch tube 、 Resonant Inductor 、 The magnetizing inductor and the resonant capacitor are characterized in that The control method comprises: Detect and judge the output power; When the output power is less than a preset first power threshold value P1 and greater than a preset second power threshold value P2, a first skip cycle working mode is entered, wherein the first skip cycle working mode includes a first cycle, the first cycle includes a first duration and a second duration, during the first duration, the upper switch tube and the lower switch tube are alternately turned on, during the second duration, the upper switch tube and the lower switch tube are turned off at the same time, and the second duration is determined by automatically adjusting the number of oscillation cycles of the midpoint of the half bridge, and the number of oscillation cycles is negatively correlated with the output power; When the output power is less than the second power threshold P2 and greater than the preset third power threshold P3, the second skip-cycle working mode is entered, wherein the second skip-cycle working mode includes a second cycle, the second cycle includes a third duration and a fourth duration, in the third duration, the upper switch tube and the lower switch tube are alternately turned on, and in the fourth duration, the upper switch tube and the lower switch tube are turned off at the same time, and the second cycle is determined according to a preset output power-second cycle frequency curve, and P1>P2>P3.

2. The control method of the half-bridge LLC resonant circuit according to claim 1, characterized in that: The method for detecting and judging the output power comprises: Obtaining an optocoupler current through an optocoupler current sampling circuit, wherein the optocoupler current sampling circuit is electrically connected to an output end of the half-bridge LLC resonant circuit; The output power is determined by the optocoupler current, wherein the optocoupler current is linearly related to the output power.

3. The control method of the half-bridge LLC resonant circuit according to claim 1, characterized in that: The first duration is determined according to a preset output power-switching frequency curve or an output power-resonant capacitor voltage change curve, and the number of times the upper switch tube and the lower switch tube are turned on and off in the first duration is preset.

4. The control method of the half-bridge LLC resonant circuit according to claim 1, characterized in that: The method for determining the second duration by automatically adjusting the number of oscillation cycles of the midpoint of the half bridge specifically includes: Acquire an initial second duration, wherein an initial value of the number of oscillation periods included in the initial second duration is preset; Obtaining an optocoupler current for characterizing the output power; The number of oscillation cycles is increased or decreased according to the optocoupler current.

5. The control method of the half-bridge LLC resonant circuit according to claim 4, characterized in that: The step of increasing or decreasing the number of oscillation cycles according to the optocoupler current specifically includes: When the optocoupler current is greater than a preset first current threshold, the number of oscillation cycles is increased by i so that the second time length increases; When the optocoupler current is less than a preset second current threshold, the number of oscillation cycles is reduced by j to reduce the second duration; wherein i and j are positive integers, and the first current threshold is greater than the second current threshold.

6. The control method of the half-bridge LLC resonant circuit according to claim 5, characterized in that: After the initial value of the number of oscillation cycles is changed, the half-bridge LLC resonant circuit is in a stable working state after a dynamic time, after which the number of oscillation cycles can be increased or decreased again.

7. The control method of the half-bridge LLC resonant circuit according to claim 1, characterized in that: The second cycle includes a third duration and a fourth duration, the third duration is determined according to a preset output power-switching frequency curve or an output power-resonant capacitor voltage change curve, and the number of times the upper switch tube and the lower switch tube are turned on and off in the third duration is pre-set.

8. The control method of the half-bridge LLC resonant circuit according to claim 1, characterized in that: The first power threshold P1 is 15%-40% of the rated load power, the second power threshold P2 is 10%-25% of the rated load power, and the third power threshold P3 is 5%-20% of the rated load power.

9. The control method of the half-bridge LLC resonant circuit according to claim 1, characterized in that: In the first jump cycle working mode, the switching frequency of the switching component composed of the upper switch tube and the lower switch tube has a frequency jump at least at one power point, and between two adjacent output powers where there is a frequency jump, the switching frequency increases linearly as the output power decreases.

10. The control method of the half-bridge LLC resonant circuit according to claim 1, characterized in that: In the second skip cycle working mode, the switching frequency of the switch component formed by the upper switch tube and the lower switch tube increases linearly as the output power decreases.

11. The control method of the half-bridge LLC resonant circuit according to claim 1, characterized in that: The cycle hopping frequency corresponding to the third power threshold P3 is greater than or equal to 20 kHz.

12. A controller for a half-bridge LLC resonant circuit, the half-bridge LLC resonant circuit comprising an upper switch tube 、 Lower switch tube 、 Resonant Inductor 、 The magnetizing inductor and the resonant capacitor are characterized in that The controller comprises: A detection and judgment module, which is used to detect and judge the output power; and A first skip cycle control module, which is used to enter a first skip cycle working mode when the output power is less than a preset first power threshold P1 and greater than a preset second power threshold P2, wherein the first skip cycle working mode includes a first cycle, the first cycle includes a first duration and a second duration, during the first duration, the upper switch tube and the lower switch tube are alternately turned on, during the second duration, the upper switch tube and the lower switch tube are turned off at the same time, and the second duration is determined by automatically adjusting the number of oscillation cycles of the midpoint of the half bridge, and the number of oscillation cycles is negatively correlated with the output power; A second skip cycle control module is used to enter a second skip cycle working mode when the output power is less than the second power threshold P2 and greater than a preset third power threshold P3, wherein the second skip cycle working mode includes a second cycle, the second cycle includes a third duration and a fourth duration, during the third duration, the upper switch tube and the lower switch tube are alternately turned on, and during the fourth duration, the upper switch tube and the lower switch tube are turned off at the same time, and the second cycle is determined according to a preset output power-second cycle frequency curve, and P1>P2>P3.

13. The controller of the half-bridge LLC resonant circuit according to claim 12, characterized in that: The first jump cycle control module also includes a second time length preset unit, an optocoupler current acquisition unit and an oscillation period adjustment unit, wherein the second time length preset unit is used to obtain an initial second time length, wherein the initial value of the number of oscillation periods included in the initial second time length is preset; the optocoupler current acquisition unit is used to obtain an optocoupler current used to characterize the output power; and the oscillation period adjustment unit is used to increase or decrease the number of oscillation periods according to the optocoupler current.

14. The controller of the half-bridge LLC resonant circuit according to claim 13, characterized in that: The oscillation period adjustment unit also includes a first oscillation period adjustment unit and a second oscillation period adjustment unit. The first oscillation period adjustment unit is used to increase the number of oscillation periods by i so as to increase the second duration when the optocoupler current is greater than a preset first current threshold; the second oscillation period adjustment unit is used to reduce the number of oscillation periods by j so as to reduce the second duration when the optocoupler current is less than a preset second current threshold; wherein i and j are positive integers, and the first current threshold is greater than the second current threshold.

15. A switching power supply, characterized in that: It comprises a half-bridge LLC resonant circuit and also comprises a controller of the half-bridge LLC resonant circuit as claimed in any one of claims 12 to 14, wherein the controller is electrically connected to the half-bridge LLC resonant circuit.

16. An electronic device, characterized in that: A controller comprising a half-bridge LLC resonant circuit as claimed in any one of claims 12 to 14 or a switching power supply as claimed in claim 15.

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