Switch mode power supply device, power supply device and communication device

Abstract

Disclosed in the present application are a switch mode power supply device, a power supply device and a communication device. When the load rate of an electric device is less than or equal to a first load rate threshold, a control circuit performs light-load mode control over a voltage conversion circuit, in order to achieve low-energy and high-efficiency operation of the voltage conversion circuit. The light-load mode control involves: when the average voltage of a capacitor drops to less than or equal to a target voltage, controlling an energy storage switch module and an energy transfer switch module to operate in a first operating state, in order to transfer energy to the electric device and the capacitor. In addition, during the conduction of the energy transfer switch module, when current flowing through an energy storage magnetic device approaches zero, both the energy storage switch module and the energy transfer switch module are controlled to turn off, thereby avoiding the backflow of energy stored in the capacitor, and thus reducing energy waste. When the average voltage of the capacitor is greater than the target voltage, both the energy storage switch module and the energy transfer switch module are controlled to turn off, thereby reducing losses and avoiding capacitor overshoot. On this basis, the switch mode power supply device can operate more efficiently.

Description

Switching power supply device, power supply device and communication device TECHNICAL FIELD

[0001] The present application relates to the technical field of switching power supply, in particular to a switching power supply device, a power supply device and a communication device. BACKGROUND

[0002] The switching power supply device is a device that converts the input voltage and outputs it to the power-consuming device to supply power to the power-consuming device. The early switching power supply device adopts diode rectification. Since the conduction voltage drop of the diode is high, the conduction loss increases in the large current application scenario, and the power conversion efficiency decreases. In order to reduce the conduction loss of the rectifier device, the synchronous rectification technology is proposed and widely used in the switching power supply device with large current output. This technology uses a switch (for example, a metal oxide semiconductor field effect transistor (MOSFET)) to replace the diode rectification.

[0003] In actual application, the power-consuming device is not always in a high energy consumption state. When the power-consuming device is converted from heavy load to light load or no load, the energy consumption of the power-consuming device will generally decrease. Based on this, in the conventional or heavy load case, the synchronous rectification of the switching power supply device can improve the conversion efficiency of the switching power supply device and effectively reduce the power consumption. In the light load or no load case, since the freewheeling switch has a bidirectional conduction characteristic, the inductor current gradually decreases during the freewheeling period and flows reversely into the freewheeling switch, which generates a large power loss and reduces the light load conversion efficiency. Moreover, when the reverse current is too large, a voltage spike will be generated across the drain-source of the freewheeling switch, which may cause the freewheeling switch to burn out in severe cases. In addition, in the light load case, the energy consumption of the power-consuming device will decrease. When the switching power supply device is always in the working state, the power loss does not decrease compared with the working state in the conventional or heavy load case, thereby causing the conversion efficiency of the switching power supply device to decrease.

[0004] SUMMARY

[0005] The present application provides a switching power supply device, a power supply device and a communication device to realize low-energy and high-efficiency working of the switching power supply device.

[0006] In a first aspect, an embodiment of the present application provides a switching power supply device, the switching power supply device comprising a voltage conversion circuit and a control circuit, an input end of the voltage conversion circuit being configured to receive an input voltage, an output end of the voltage conversion circuit being configured to be connected to an electrical device, and a capacitor being connected in parallel to the output end of the voltage conversion circuit. The voltage conversion circuit comprises an energy storage magnetic device, an energy storage switching assembly, and an energy transmission switching assembly. The energy storage switching assembly and the energy transmission switching assembly are respectively connected to the energy storage magnetic device. When the voltage conversion circuit is working, the energy storage switching assembly is configured to transmit energy at the input end of the voltage conversion circuit to the energy storage magnetic device, and the energy transmission switching assembly is configured to transmit energy at the energy storage magnetic device to the electrical device and the capacitor to supply power to the electrical device.

[0007] Since the energy consumed by the electrical device is not always large, the energy consumed by the electrical device is related to the load rate of the electrical device. When the load rate of the electrical device is high, the energy consumed is large. Conversely, when the load rate of the electrical device is low, the energy consumed is small. Based on this, by setting a first load rate threshold, the load rate of the electrical device is compared with the first load rate threshold. When the load rate of the electrical device is less than or equal to the first load rate threshold, the control circuit is configured to control the voltage conversion circuit in a light-load mode to realize low-energy and high-efficiency working of the voltage conversion circuit.

[0008] In addition, the control process in the light-load mode can include the following process: according to the size relationship between the average voltage of the capacitor and the target voltage, the working states of the energy storage switching assembly and the energy transmission switching assembly are controlled. Specifically, when the average voltage of the capacitor decreases to be less than or equal to the target voltage, the control circuit controls the energy storage switching assembly and the energy transmission switching assembly to work in a first working state. In the first working state, the energy storage switching assembly is turned on first, and the energy transmission switching assembly is turned on later, so that the energy at the input end of the voltage conversion circuit is transmitted to the electrical device and the capacitor through the current flowing through the energy storage magnetic device. In addition, during the process of turning on the energy transmission switching assembly, when the current flowing through the energy storage magnetic device approaches zero, the energy storage switching assembly and the energy transmission switching assembly are both turned off, thereby avoiding the backflow of the energy stored in the capacitor. Based on this, when the energy storage switching assembly and the energy transmission switching assembly work in the first working state, the direction of energy transmission is from the input end of the voltage conversion circuit to the output end of the voltage conversion circuit, thereby avoiding energy backflow, reducing energy waste, and further reducing loss and improving the conversion efficiency of the voltage conversion circuit.

[0009] Since the output end of the voltage conversion circuit is connected in parallel with the capacitor, during the energy transmission process of the voltage conversion circuit, the capacitor will be charged, and the voltage on the capacitor will gradually increase. When the average voltage of the capacitor is greater than the target voltage, it indicates that the energy transmitted by the voltage conversion circuit is sufficient to power the electrical equipment, and the control circuit can control the energy storage switch assembly and the energy transmission switch assembly to be both disconnected, so that the voltage conversion circuit temporarily stops the energy transmission process, thereby reducing the loss and avoiding overvoltage of the capacitor. Moreover, since the capacitor has the function of storing energy, when the energy storage switch assembly and the energy transmission switch assembly are both disconnected, the electrical equipment can be powered by the energy stored in the capacitor, avoiding power failure of the electrical equipment.

[0010] Based on this, when the load rate of the electrical equipment is less than or equal to the first load rate threshold, the voltage conversion circuit is controlled in the light load mode, which can make the switching power supply device work more efficiently.

[0011] The signal for controlling the conduction and disconnection of the energy storage switch assembly and the energy transmission switch assembly is a pulse width modulation (PWM) signal. The PWM signal is a periodic control signal, and the energy storage switch assembly and the energy transmission switch assembly can work in one switching period or a plurality of switching periods that occur in sequence, so that in at least one switching period, the energy storage switch assembly is turned on first and the energy transmission switch assembly is turned on later. Based on this, in some embodiments, the conduction time of the energy storage switch assembly and the energy transmission switch assembly in at least two consecutive switching periods can be sequentially reduced, so that based on the process of sequentially reducing the conduction time of the energy storage switch assembly and the energy transmission switch assembly, the energy transmitted is sequentially reduced, thereby gradually reducing the energy supplied to the capacitor, avoiding sudden change of the output voltage, and improving the stability of the output voltage.

[0012] In some embodiments, after controlling the energy storage switch assembly and the energy transmission switch assembly to be both disconnected for a predetermined time, i.e., after controlling the energy storage switch assembly and the energy transmission switch assembly to enter the second working state for a predetermined time, the mode control of the voltage conversion circuit can be performed again according to the size of the load rate of the electrical equipment, thereby realizing the cyclic control of the mode of the voltage conversion circuit, so that the voltage conversion circuit can work more efficiently. Based on this, the mode control of the voltage conversion circuit according to the size of the load rate of the electrical equipment can include: when the load rate of the electrical equipment is less than or equal to the first load rate threshold, the light load mode control described above is performed.

[0013] In some embodiments, for the predetermined time length, a suitable value can be selected based on performance requirements (such as the ripple of the output voltage of the voltage conversion circuit), and some cost considerations. For example, the predetermined time length can be set to 0.1-1000 switching periods. However, in actual applications, if the predetermined time length is too short, that is, after the energy storage switch assembly and the energy transmission switch assembly are both turned off, the process of mode control of the voltage conversion circuit according to the load rate of the electrical equipment is performed soon, which requires a better controller to meet the requirements of this mode, resulting in increased cost. If the predetermined time length is too long, after the energy storage switch assembly and the energy transmission switch assembly are both turned off, a long time is waited before the process of mode control of the voltage conversion circuit according to the load rate of the electrical equipment is performed, which will result in too large ripple of the output voltage of the voltage conversion circuit, affecting the performance. Therefore, considering the cost and performance, in the embodiments of the present application, the first set time length is set to 5-20 switching periods, to balance the cost and performance. For example, the first set time length can be 5, 7, 9, 10, 12, 15, 18 or 20 switching periods, etc., which are not limited herein.

[0014] In the embodiments of the present application, when the energy storage switch assembly and the energy transmission switch assembly are controlled to work in the first working state, during the process of turning on the energy transmission switch assembly, the current flowing through the energy storage magnetic element can be detected, and when the current flowing through the energy storage magnetic element decreases to near zero in a positive direction, the control circuit can control the energy storage switch assembly and the energy transmission switch assembly to work in the second working state. In this way, the energy transmission switch assembly can be controlled without additional devices, and the hardware structure of the switching power supply device does not need to be additionally designed, reducing the design cost. In the embodiments of the present application, the PWM signal for controlling the energy transmission switch assembly to turn on and off can not be obtained in the 1-D2 (D2 represents the duty cycle of the energy storage switch assembly) manner, but can be obtained by detecting the current flowing through the energy storage magnetic element or by using an algorithm.

[0015] In some embodiments, the energy storage switch assembly and the energy transmission switch assembly are controlled to work in the second working state by detecting the current flowing through the energy storage magnetic component. For example, the switching power supply device further comprises a first sampling circuit configured to detect the current flowing through the energy storage magnetic component. The control circuit is connected to the first sampling circuit. When the current flowing through the energy storage magnetic component is close to zero, the control circuit controls the energy storage switch assembly and the energy transmission switch assembly to be both off by detecting the current flowing through the energy storage magnetic component is close to zero through the first sampling circuit. Since the switching power supply device usually has a circuit for collecting the current of the energy storage magnetic component, the first sampling circuit can reuse the circuit, and no additional circuit is needed to detect the current flowing through the energy storage magnetic component. Therefore, the hardware structure of the switching power supply device does not need to be additionally designed, and the design cost is reduced.

[0016] For example, the first sampling circuit includes, but is not limited to, a Hall sensor or a current transformer. In addition, the control circuit can perform a series of protection operations according to the current detected by the first sampling circuit to improve the reliability of the voltage conversion circuit.

[0017] In some embodiments, the energy storage switch assembly and the energy transmission switch assembly are controlled to work in the second working state by using an algorithm. For example, when the current flowing through the energy storage magnetic component is close to zero, the control circuit controls the energy storage switch assembly and the energy transmission switch assembly to be both off by determining the current flowing through the energy storage magnetic component is close to zero according to the voltage at the input end of the voltage conversion circuit, the voltage at the output end of the voltage conversion circuit, and the conduction time of the energy storage switch assembly. By setting this way, the energy transmission switch assembly can be controlled to be off by using an algorithm, so that the energy transmission switch assembly can be controlled without additional devices, and the hardware structure of the switching power supply device does not need to be additionally designed, and the design cost is reduced.

[0018] The voltage conversion circuit has many topologies. In some topologies of the voltage conversion circuit with a physical inductor, the physical inductor can be used as the energy storage magnetic component for charging and discharging in the voltage conversion circuit. For example, the voltage conversion circuit includes an inductor, the energy storage switch assembly and the energy transmission switch assembly are connected to the inductor, and the energy storage magnetic component is the inductor. Therefore, the current flowing through the energy storage magnetic component is the current flowing through the inductor, and the energy storage switch assembly and the energy transmission switch assembly are controlled to work in the second working state when the current flowing through the inductor is close to zero.

[0019] In another part of the topology of the voltage conversion circuit with the transformer, no physical inductor can be provided, and the transformer can be used as an energy storage magnetic element for charging and discharging in the voltage conversion circuit. Exemplarily, the voltage conversion circuit includes the transformer, the energy storage switch assembly is connected to the primary winding of the transformer, the energy transmission switch assembly is connected to the secondary winding of the transformer, the energy storage magnetic device is the transformer, and the current flowing through the energy storage magnetic device is the current flowing through the secondary winding of the transformer. Therefore, the energy storage switch assembly and the energy transmission switch assembly can be controlled to work in the second working state based on the current flowing through the secondary winding of the transformer being close to zero.

[0020] Since the load rate of the electrical equipment is relatively high at some time, based on this, another way to control the mode of the voltage conversion circuit according to the size of the load rate of the electrical equipment is to set a second load rate threshold, which is greater than the first load rate threshold, and compare the load rate of the electrical equipment with the second load rate threshold. When the load rate of the electrical equipment is greater than the second load rate threshold, it indicates that the load rate of the electrical equipment is high and the energy consumption is high. In order to meet the power supply demand of the electrical equipment, the voltage conversion circuit can be controlled in the normal mode to transfer more energy to the electrical equipment side and ensure the efficient work of the electrical equipment.

[0021] Specifically, when the voltage conversion circuit works in the normal mode, the control circuit can control the energy storage switch assembly and the energy transmission switch assembly to work in the third working state, and in the third working state, the energy storage switch assembly and the energy transmission switch assembly are complementary on. In specific implementation, when the voltage conversion circuit works in the normal mode, the control circuit can calculate the duty cycle of the energy storage switch assembly according to the average voltage of the capacitor and the target voltage, send the PWM signal to the energy storage switch assembly and the energy transmission switch assembly based on the calculated duty cycle, and control the energy storage switch assembly and the energy transmission switch assembly to be complementary on to provide sufficient energy for the electrical equipment.

[0022] In order to avoid directly controlling the energy storage switch assembly and the energy transmission switch assembly to be complementary on, which leads to large voltage ripple at the output end of the voltage conversion circuit, in some embodiments, for the process of controlling the energy storage switch assembly and the energy transmission switch assembly to be complementary on in the third working state, the on time of the energy storage switch assembly and the energy transmission switch assembly can be controlled to increase in turn in at least two switching periods until the energy storage switch assembly and the energy transmission switch assembly are complementary on.

[0023] In some embodiments, after the predetermined time duration that both the energy storage switch assembly and the energy transmission switch assembly are disconnected, the mode control of the voltage conversion circuit can also be performed according to the size of the load rate of the electrical equipment, so as to realize the cycle control of the mode of the voltage conversion circuit, so that the voltage conversion circuit can work further low-energy and high-efficiently. Based on this, the mode control of the voltage conversion circuit according to the size of the load rate of the electrical equipment can include: when the load rate of the electrical equipment is less than or equal to the first load rate threshold, the above-mentioned light load mode control is performed. When the load rate of the electrical equipment is greater than the second load rate threshold, the above-mentioned normal mode control is performed. When the load rate of the electrical equipment is greater than the first load rate threshold and less than or equal to the second load rate threshold, the mode of the voltage conversion circuit is controlled to be the same as the previous mode, for example, the mode of the voltage conversion circuit in the next switching period is controlled to be the same as the mode in the previous switching period. When the mode of the voltage conversion circuit in the previous switching period is the normal mode, then the mode of the voltage conversion circuit in the next switching period is also the normal mode. Or, when the mode of the voltage conversion circuit in the previous switching period is the light load mode, then the mode of the voltage conversion circuit in the next switching period is also the light load mode. In this way, when the load rate is between the first load rate threshold and the second load rate threshold, the working of the voltage conversion circuit is controlled based on the previous mode, which can reduce the ripple of the output voltage of the voltage conversion circuit caused by mode switching and improve the stability of the output voltage.

[0024] In addition, when the first load rate threshold and the second load rate threshold are equal, due to the limitation of sampling accuracy, the mode of the voltage conversion circuit may be controlled to switch all the time, causing the output voltage of the voltage conversion circuit to oscillate. For example, if the first load rate threshold and the second load rate threshold are both 2, and the actual load rate of the electrical equipment is 2, and the sampling accuracy is ±0.05, then the collected load rate of the electrical equipment may be 2.05 or 1.95, so that when the collected load rate of the electrical equipment is 2.05, the normal mode control of the voltage conversion circuit is performed. When the collected load rate of the electrical equipment is 1.95, the light load mode control of the voltage conversion circuit is performed. In this way, the voltage conversion circuit will frequently switch between the light load mode and the normal mode, causing the output voltage of the voltage conversion circuit to oscillate. Therefore, in the embodiments of the present application, the second load rate threshold is greater than the first load rate threshold, for example, if the first load rate threshold is 1.5 and the second load rate threshold is 2.5, and the actual load rate of the electrical equipment is 2 and the sampling accuracy is ±0.05, then the collected load rate of the electrical equipment may be 2.05 or 1.95, so that when the collected load rate of the electrical equipment is 2.05 or 1.95, the working of the voltage conversion circuit can be controlled based on the previous mode, which can reduce the ripple of the output voltage of the voltage conversion circuit and improve the stability of the output voltage.

[0025] In a specific implementation, the magnitude relationship between the load rate of the electrical equipment and the first load rate threshold, the second load rate threshold and the third load rate threshold can have various determination manners, which are exemplified as follows.

[0026] The first determination manner: the magnitude relationship between the load rate of the electrical equipment and the first load rate threshold, the second load rate threshold and the third load rate threshold can be determined based on the magnitude relationship between the current at the input end of the electrical equipment and the load current threshold. The load current threshold can include the first load current threshold, the second load current threshold and the third load current threshold which are sequentially increased in value. When the current at the input end of the electrical equipment is less than or equal to the first load current threshold, it is determined that the load rate of the electrical equipment is less than or equal to the first load rate threshold. When the current at the input end of the electrical equipment is greater than the first load current threshold and less than or equal to the second load current threshold, it is determined that the load rate of the electrical equipment is greater than the first load rate threshold and less than or equal to the second load rate threshold. When the current at the input end of the electrical equipment is greater than the third load current threshold, it is determined that the load rate of the electrical equipment is greater than the third load rate threshold. In order to obtain the current at the input end of the electrical equipment, a second sampling circuit can be arranged in the switching power supply to detect the current at the input end of the electrical equipment through the second sampling circuit. Thus, the control circuit can determine the magnitude relationship between the load rate of the electrical equipment and different load rate thresholds based on the magnitude relationship between the current at the input end of the electrical equipment detected by the second sampling circuit in the switching power supply and the load current threshold.

[0027] Exemplarily, the second sampling circuit is arranged in the switching power supply and is connected between the output end of the voltage conversion circuit and the electrical equipment.

[0028] As an example, the second sampling circuit can include an operational amplifier and a first sampling resistor connected between the output end of the voltage conversion circuit and the input end of the electrical equipment. The input end of the operational amplifier is connected to both ends of the first sampling resistor, and the output end of the operational amplifier is connected to the control circuit. Since the current at the input end of the electrical equipment suddenly increases, the voltage difference between both ends of the first sampling resistor will increase, and the signal output by the operational amplifier will change. With this arrangement, a simple structure can be used, i.e., the control circuit can identify the current at the input end of the electrical equipment based on the signal output by the operational amplifier, and then determine the magnitude relationship between the load rate of the electrical equipment and different load rate thresholds according to the identified current at the input end of the electrical equipment.

[0029] The second determination manner: the load rate of the electrical equipment and the size relationship among the first load rate threshold, the second load rate threshold and the third load rate threshold can be determined based on the size relationship between the current detected by the first sampling circuit and the magnetic element current threshold. The magnetic element current threshold can include the first magnetic element current threshold, the second magnetic element current threshold and the third magnetic element current threshold which increase in value in sequence. When the current detected by the first sampling circuit is less than or equal to the first magnetic element current threshold, it is determined that the load rate of the electrical equipment is less than or equal to the first load rate threshold. When the current detected by the first sampling circuit is greater than the first magnetic element current threshold and less than or equal to the second magnetic element current threshold, it is determined that the load rate of the electrical equipment is greater than the first load rate threshold and less than or equal to the second load rate threshold. When the current detected by the first sampling circuit is greater than the third magnetic element current threshold, it is determined that the load rate of the electrical equipment is greater than the third load rate threshold.

[0030] The third determination manner: the control circuit can also communicate with the electrical equipment. The trigger signal sent by the electrical equipment to the control circuit directly, and the control circuit can determine the size relationship among the load rate of the electrical equipment and different load rate thresholds according to the trigger signal.

[0031] Exemplarily, the electrical equipment can send the trigger signal to the control circuit based on the amount of data transmitted by itself. For example, the amount of data transmitted by the electrical equipment increases, which indicates that the load rate of the electrical equipment increases. Specifically, the amount of data threshold can be set. The electrical equipment can compare the amount of data transmitted by itself with the amount of data threshold, and determine the size relationship among the load rate of the electrical equipment and the first load rate threshold, the second load rate threshold and the third load rate threshold according to the size relationship between the amount of data transmitted by itself and the amount of data threshold. The amount of data threshold can include the first amount of data threshold, the second amount of data threshold and the third amount of data threshold which increase in value in sequence. When the amount of data transmitted by the electrical equipment is less than or equal to the first amount of data threshold, it is determined that the load rate of the electrical equipment is less than or equal to the first load rate threshold. When the amount of data transmitted by the electrical equipment is greater than the first amount of data threshold and less than or equal to the second amount of data threshold, it is determined that the load rate of the electrical equipment is greater than the first load rate threshold and less than or equal to the second load rate threshold. When the amount of data transmitted by the electrical equipment is greater than the third amount of data threshold, it is determined that the load rate of the electrical equipment is greater than the third load rate threshold.

[0032] In some embodiments, one or more voltage conversion circuits can be provided in the switching power supply device. When multiple voltage conversion circuits are provided, the input terminals of the multiple voltage conversion circuits are connected in parallel, and the output terminals of the multiple voltage conversion circuits are connected in parallel, so that the multiple voltage conversion circuits in parallel are used to supply power to the powered device. Moreover, the control circuit is connected to each voltage conversion circuit respectively, and each voltage conversion circuit can be controlled by using the above-mentioned mode respectively. Alternatively, the control circuit can also control part of the voltage conversion circuits to use the above-mentioned mode for control and control another part of the voltage conversion circuits to stop working, so that only part of the voltage conversion circuits are used to supply power to the powered device, thereby further reducing the loss. In this way, the third load rate threshold value can be used to determine whether all the voltage conversion circuits are used to work to realize multi-phase working or part of the voltage conversion circuits are used to realize partial phase working or one voltage conversion circuit is used to realize single-phase working.

[0033] In a second aspect, the embodiments of the present application further provide a power supply device, which comprises a power supply device and one or more switching power supply devices. The switching power supply device is the switching power supply device in the first aspect or any of the embodiments of the first aspect. The input terminal of the power supply device is used to receive a power supply voltage, the output terminal of the power supply device is connected to the input terminal of the switching power supply device, and the output terminal of the switching power supply device is used to connect to a powered device. In addition, the technical effects of the corresponding solutions in the second aspect can be referred to the technical effects of the corresponding solutions in the first aspect or any of the embodiments of the first aspect, and the repeated parts will not be described in detail.

[0034] In a third aspect, the embodiments of the present application further provide a communication device, which comprises a powered device and one or more switching power supply devices. The switching power supply device is the switching power supply device in the first aspect or any of the embodiments of the first aspect. The output terminal of the switching power supply device is connected to the powered device. In addition, the technical effects of the corresponding solutions in the third aspect can be referred to the technical effects of the corresponding solutions in the first aspect or any of the embodiments of the first aspect, and the repeated parts will not be described in detail. BRIEF DESCRIPTION OF DRAWINGS

[0035] FIG. 1 is a structural block diagram of a communication device provided by the embodiments of the present application;

[0036] FIG. 2 is a structural schematic diagram of a power supply device and a powered device provided by the embodiments of the present application;

[0037] FIG. 3a is a circuit topology diagram of a voltage conversion circuit in the embodiments of the present application;

[0038] FIG. 3b is another circuit topology diagram of a voltage conversion circuit in the embodiments of the present application;

[0039] Fig. 3c is another circuit topology of the voltage conversion circuit in the embodiment of the present application;

[0040] Fig. 3d is another circuit topology of the voltage conversion circuit in the embodiment of the present application;

[0041] Fig. 3e is another circuit topology of the voltage conversion circuit in the embodiment of the present application;

[0042] Fig. 3f is another circuit topology of the voltage conversion circuit in the embodiment of the present application;

[0043] Fig. 3g is another circuit topology of the voltage conversion circuit in the embodiment of the present application;

[0044] Fig. 3h is another circuit topology of the voltage conversion circuit in the embodiment of the present application;

[0045] Fig. 4a is a signal timing diagram of the voltage conversion circuit in the normal mode in the embodiment of the present application;

[0046] Fig. 4b is another signal timing diagram of the voltage conversion circuit in the normal mode in the embodiment of the present application;

[0047] Fig. 5 is a circuit structure schematic diagram of the switching power supply device in the embodiment of the present application;

[0048] Fig. 6a is a signal timing diagram of the voltage conversion circuit in the light load mode in the embodiment of the present application;

[0049] Fig. 6b is another signal timing diagram of the voltage conversion circuit in the light load mode in the embodiment of the present application;

[0050] Fig. 7 is another signal timing diagram of the voltage conversion circuit in the light load mode in the embodiment of the present application;

[0051] Fig. 8 is another circuit structure schematic diagram of the switching power supply device in the embodiment of the present application;

[0052] Fig. 9 is another circuit structure schematic diagram of the switching power supply device in the embodiment of the present application.

[0053] Explanation of Reference Signs

[0054] 10 - communication device; 100 - power supply device; 110 - power supply device; 120 - switching power supply device; 121 - voltage conversion circuit; 122 - control circuit; 123 - first sampling circuit; 124 - second sampling circuit; 130 - input filter circuit; 140 - output filter circuit; 200 - power consuming device. DETAILED DESCRIPTION

[0055] In order to make the purposes, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings. The specific operation methods in the method embodiments can also be applied to the device embodiments or system embodiments. It should be noted that in the description of the present application, "at least one" refers to one or more, wherein more refers to two or more. In view of this, "more" in the embodiments of the present application can also be understood as "at least two". "And / or", which describes the association relationship of the associated objects, means that there can be three kinds of relationships, for example, A and / or B can represent: A exists alone, A and B exist together, and B exists alone. In addition, the character " / ", if not specially stated, generally represents that the associated objects before and after are in an "or" relationship. In addition, the words "first", "second", etc. are only used for the purpose of distinguishing the description and cannot be understood as indicating or implying relative importance. In addition, "connection" in the embodiments of the present application refers to electrical connection, and the connection between two electrical elements can be direct connection between the two electrical elements or indirect connection through an intermediate medium. For example, A is connected with B, which can be direct connection between A and B, or indirect connection between A and B through one or more other electrical elements, for example, A is connected with B, which can be direct connection between A and C, direct connection between C and B, and connection between A and B through C.

[0056] It should be noted that the same reference signs in the drawings of the present application represent the same or similar structures, so repeated description thereof will be omitted. The expressions of position and direction described in the present application are described with reference to the drawings, but changes can also be made as needed, and the changes made are included in the protection scope of the present application. The drawings of the present application are only used to show the relative positional relationship and do not represent the true proportion.

[0057] In order to facilitate the understanding of the switching power supply device, power supply device and communication device provided by the embodiments of the present application, the application scenarios thereof will be introduced first as follows.

[0058] The switching power supply device provided by the embodiments of the present application can be applied to any power supply device which converts voltage (for example, direct current (DC) voltage or alternating current (AC) voltage). The power supply device can be applied to a communication device (for example, a base station) to supply power to a power consuming device in the communication device. The power consuming device can be an AC power consuming device or a DC power consuming device. Exemplarily, the power consuming device can be a computer, a server, a power amplifier, a hardware single board, etc. The power supply device in the embodiments of the present application can also be applied to a scenario of supplying power to a family or an industry, for example, the power consuming device is an electrical device (for example, a refrigerator, an air conditioner, etc.). The power supply device in the embodiments of the present application can also be applied to a micro-grid, for example, a photovoltaic micro-grid. Of course, the power supply device can also be applied to other devices, which are not limited herein. The switching power supply device, the power supply device and the communication device provided by the embodiments of the present application are described below in combination with the drawings.

[0059] FIG. 1 is a structural block diagram of a communication device according to an embodiment of the present application. Referring to FIG. 1, the communication device 10 can include a power supply device 100 and a powered device 200. The power supply device 100 can include a power supply source device 110 and a switching power supply device 120. The switching power supply device 120 includes a voltage conversion circuit 121. An input terminal of the power supply source device 110 is connected to an input power source. An output terminal of the power supply source device 110 is connected to an input terminal of the voltage conversion circuit 121 in the switching power supply device 120 through a wire (e.g., Aus+, Aus-). An output terminal of the voltage conversion circuit 121 in the switching power supply device 120 is connected to the powered device 200. The switching power supply device 120 further includes a control circuit 122. The control circuit 122 can control the voltage conversion circuit 121 to work, so as to convert the voltage at the input terminal of the voltage conversion circuit 121 and output the converted voltage to the powered device 200 to supply power to the powered device 200. The control circuit 122 can be a field programmable gate array (FPGA), a general central processing unit (CPU), a general processor, a digital signal processing (DSP), an application specific integrated circuits (ASIC), or any other programmable logic device, transistor logic device, hardware component, or any combination thereof. The control circuit 122 can implement or execute various exemplary logical blocks, modules, and circuits described in connection with the present disclosure. The control circuit 122 can also be a combination of computing functions, such as one or more microprocessor combinations, combinations of DSP and microprocessor, and the like. In addition, it is worth mentioning that those skilled in the art can understand that the hardware structure of the communication device 10 shown in FIG. 1 does not constitute a limitation on the communication device 10. The communication device 10 according to an embodiment of the present application can include more or fewer components than those shown in the figure, can combine two or more components, or can have a different component configuration. In addition, the various components shown in FIG. 1 can be implemented in hardware, software, or a combination of hardware and software, including one or more signal processing and / or application specific integrated circuits.

[0060] In some embodiments of the present application, the switching power supply device 120 can be a direct current switching power supply device, the power supply device 110 can convert the alternating current or the direct current to output the direct current to the switching power supply device 120, when the electric device 200 is a direct current electric device, the voltage conversion circuit 121 can be set as a DC-DC conversion circuit to convert the direct current output by the power supply device 110 to output the direct current to the electric device 200 to supply power for the electric device 200. When the electric device 200 is an alternating current electric device, the voltage conversion circuit 121 can be set as a DC-AC conversion circuit to convert the direct current output by the power supply device 110 to output the alternating current to the electric device 200 to supply power for the electric device 200.

[0061] In some embodiments of the present application, the switching power supply device 120 can be a direct current switching power supply device, the power supply device 110 can convert the alternating current or the direct current to output the direct current to the switching power supply device 120, when the electric device 200 is a direct current electric device, the voltage conversion circuit 121 can be set as a DC-DC conversion circuit to convert the direct current output by the power supply device 110 to output the direct current to the electric device 200 to supply power for the electric device 200. When the electric device 200 is an alternating current electric device, the voltage conversion circuit 121 can be set as a DC-AC conversion circuit to convert the direct current output by the power supply device 110 to output the alternating current to the electric device 200 to supply power for the electric device 200.

[0062] In actual application, electromagnetic interference (EMI) has certain influence on normal work of a circuit. In the embodiment of the present application, in order to improve EMI filtering, referring to FIG. 2, which is a structural schematic diagram of a power supply device and a power consumption device provided in the embodiment of the present application, an input filter circuit 130 is arranged between the power supply device 110 and the voltage conversion circuit 121, EMI filtering is performed through the input filter circuit 130, and power smoothing can also be performed through the input filter circuit 130 to provide a stable input voltage for the voltage conversion circuit 121. Exemplarily, the input filter circuit 130 can be an LC (inductor-capacitor) filter network, and the input filter circuit 130 is connected between the wires Aus+ and Aus- and the switching power supply device 120. For example, the input filter circuit 130 includes capacitors C1-C8, resistors R1-R6 and filter inductors Lv1-Lv2, wherein the first ends of the capacitors C1-C8 and the wire Aus+ are connected to the positive input terminal Vin+ of the voltage conversion circuit 121, the second ends of the capacitors C1-C6 are connected to the first ends of the resistors R1-R6 in one-to-one correspondence, the second ends of the resistors R1-R3 and the first end of the filter inductor Lv1 are connected to the wire Aus-, the second ends of the resistors R4-R6, the second end of the filter inductor Lv1, the second end of the capacitor C7 and the first end of the filter inductor Lv2 are connected to each other, and the second end of the filter inductor Lv2 and the second end of the capacitor C8 are connected to the negative input terminal Vin- of the voltage conversion circuit 121. In a specific embodiment, the input filter circuit 130 can be arranged in the switching power supply device 120 to be integrated in the switching power supply device 120. Alternatively, the input filter circuit 130 can also be arranged outside the switching power supply device 120. It is worth mentioning that a person skilled in the art can understand that the hardware structure of the input filter circuit 130 shown in FIG. 2 does not constitute a limitation on the input filter circuit 130, and the input filter circuit 130 provided in the embodiment of the present application can include more or fewer components than those shown, can combine two or more components, or can have a different component configuration.

[0063] And, in order to smooth the current and voltage output by the switching power supply device 120 to provide a stable output voltage to the powered device, referring to FIG. 2, an output filter circuit 140 is arranged between the voltage conversion circuit 121 and the powered device 200, and the voltage output by the voltage conversion circuit 121 is filtered by the output filter circuit 140 to provide a stable input voltage to the powered device 200. Exemplarily, the output filter circuit 140 can be an LC filter network. For example, the output filter circuit 140 includes capacitors C9-C10 and a filter inductor Lv3, the first end of the capacitors C9-C10, the positive output end Vou+ of the voltage conversion circuit 121 and the positive input end of the powered device are connected to each other, the second end of the capacitor C9, the first end of the filter inductor Lv3 and the negative output end Vou- of the voltage conversion circuit 121 are connected to each other, and the second end of the capacitor C10, the second end of the filter inductor Lv3 and the negative input end of the powered device are connected to each other. In specific embodiments, the output filter circuit 140 can be arranged in the switching power supply device 120 or in the line between the switching power supply device 120 and the powered device 200. It is worth mentioning that those skilled in the art can understand that the hardware structure of the output filter circuit 140 shown in FIG. 2 does not constitute a limitation on the output filter circuit 140, and the output filter circuit 140 provided by the embodiments of the present application can include more or fewer components than shown, can combine two or more components, or can have a different component configuration.

[0064] In actual applications, the voltage conversion circuit 121 has an energy storage magnetic element, an energy storage switching assembly and an energy transmission switching assembly, and the energy storage switching assembly and the energy transmission switching assembly are respectively connected to the energy storage magnetic element. The connection can be an electrical connection, i.e., the energy storage switching assembly and the energy transmission switching assembly can be directly connected to the energy storage magnetic element or indirectly connected to the energy storage magnetic element through other components, or the connection can also mean a coupling connection. Moreover, when the voltage conversion circuit 121 is working, the energy storage switching assembly and the energy transmission switching assembly are alternately turned on, and when the energy storage switching assembly is turned on, the energy of the input end of the voltage conversion circuit 121 can be transmitted to the energy storage magnetic element. When the energy transmission switching assembly is turned on, the energy of the energy storage magnetic element can be transmitted to the powered device 200. Specifically, the energy of the input end of the voltage conversion circuit 121 can be transmitted to the powered device 200 and a capacitor (which can be the capacitor C9 in the output filter circuit 140, or the capacitor can also be other capacitors connected in parallel to the output end of the voltage conversion circuit 121, and the following is described by taking the capacitor C9 as an example) through the charging and discharging of the energy storage magnetic element. It is worth mentioning that the voltage conversion circuit 121 has various topologies, so that the energy storage switching assembly and the energy transmission switching assembly can each have one or more switches, and the following is described by taking the voltage conversion circuit 121 as a DC-DC conversion circuit as an example.

[0065] Fig. 3a is a circuit topology of the voltage conversion circuit in the embodiment of the present application. Referring to Fig. 3a, the voltage conversion circuit 121 can be set as an inverting Buck-Boost circuit 311, for example, which includes switches SA1 and SA2 and an inductor LA. The first end of the inductor LA, the positive input end Vin+ of the voltage conversion circuit 121 and the negative output end Vou- of the voltage conversion circuit 121 are connected to each other. The first end of the switch SA1 is connected to the negative input end Vin- of the voltage conversion circuit 121. The second end of the switch SA1, the first end of the switch SA2 and the second end of the inductor LA are connected to each other. The second end of the switch SA2 is connected to the positive output end Vou+ of the voltage conversion circuit 121. The control ends of the switches SA1 and SA2 are connected to the control circuit 122. When the inverting Buck-Boost circuit 311 is working, the control circuit 122 sends pulse width modulation (PWM) signals to the switches SA1 and SA2 respectively to control the conduction and disconnection of the switches SA1 and SA2. When the switch SA1 is conducting, the switch SA2 is disconnected, the current flowing through the inductor LA increases positively, and the energy at the input end of the voltage conversion circuit 121 can be transferred to the inductor LA. When the switch SA1 is disconnected, the switch SA2 is conducting, the current flowing through the inductor LA decreases positively, and the energy of the inductor LA can be transferred to the electric device 200 and the capacitor C9 to supply power to the electric device 200. Therefore, the switch SA1 can be used as an energy storage switch component, the switch SA2 can be used as an energy transmission switch component, and the inductor LA can be used as an energy storage magnetic element for charging and discharging.

[0066] Fig. 3b is another circuit topology of the voltage conversion circuit in the embodiment of the present application. Referring to Fig. 3b, the voltage conversion circuit 121 can be configured as a Buck circuit 312, which includes, for example, switches SB1 and SB2 and an inductor LB. The first terminal of the switch SB1 is connected to the positive input terminal Vin+ of the voltage conversion circuit 121, the first terminal of the switch SB2, the negative input terminal Vin- of the voltage conversion circuit 121 and the negative output terminal Vou- of the voltage conversion circuit 121 are connected to each other, the first terminal of the inductor LB, the second terminal of the switch SB1 and the second terminal of the switch SB2 are connected to each other, and the second terminal of the inductor LB is connected to the positive output terminal Vou+ of the voltage conversion circuit 121. Moreover, the control terminals of the switches SB1 and SB2 are connected to the control circuit 122, and the control circuit 122 sends PWM signals to the switches SB1 and SB2 to control the on and off of the switches SB1 and SB2 when the Buck circuit 312 is working. When the switch SB1 is on, the switch SB2 is off, the current flowing through the inductor LB increases in a positive direction, and the energy at the input terminal of the voltage conversion circuit 121 can be transferred to the inductor LB. When the switch SB1 is off, the switch SB2 is on, the current flowing through the inductor LB decreases in a positive direction, and the energy of the inductor LB can be transferred to the load 200 and the capacitor C9 to supply power to the load 200. Therefore, the switch SB1 can be used as an energy storage switch component, the switch SB2 can be used as an energy transmission switch component, and the inductor LB can be used as an energy storage magnetic element for charging and discharging.

[0067] Fig. 3c is another circuit topology of the voltage conversion circuit in the embodiment of the present application. Referring to Fig. 3c, the voltage conversion circuit 121 can be configured as a Boost circuit 313, which includes, for example, switches SC1 and SC2 and an inductor LC. The first terminal of the inductor LC is connected to the positive input terminal Vin+ of the voltage conversion circuit 121, the second terminal of the inductor LC is connected to the second terminal of the switch SC1 and the second terminal of the switch SC2, the first terminal of the switch SC1 is connected to the positive output terminal Vou+ of the voltage conversion circuit 121, and the first terminal of the switch SC2 is connected to the negative output terminal Vou- of the voltage conversion circuit 121. Based on this, when the Boost circuit 313 is working, the control terminals of the switches SC1 and SC2 receive PWM signals to control the on and off of the switches SC1 and SC2. When the switch SC2 is on, the switch SC1 is off, the current flowing through the inductor LC increases in a positive direction, and the energy at the input terminal of the voltage conversion circuit 121 can be transferred to the inductor LC. When the switch SC2 is off, the switch SC1 is on, the current flowing through the inductor LC decreases in a positive direction, and the energy of the inductor LC can be transferred to the load 200 and the capacitor C9 to supply power to the load 200. Therefore, the switch SC2 can be used as an energy storage switch component, the switch SC1 can be used as an energy transmission switch component, and the inductor LC can be used as an energy storage magnetic element for charging and discharging.

[0068] Fig. 3d is another circuit topology of the voltage conversion circuit in the embodiment of the present application. Referring to Fig. 3d, the voltage conversion circuit 121 can be configured as a Cuk circuit 314, which includes switches SD1 and SD2, inductors LD1 and LD2, and a capacitor CD. The first terminal of the switch SD1, the first terminal of the switch SD2, the positive input terminal Vin+ of the voltage conversion circuit 121, and the negative output terminal Vou- of the voltage conversion circuit 121 are connected to each other. The first terminal of the inductor LD1 is connected to the negative input terminal Vin- of the voltage conversion circuit 121. The second terminal of the inductor LD1, the first terminal of the capacitor CD, and the second terminal of the switch SD1 are connected to each other. The second terminal of the capacitor CD, the second terminal of the switch SD2, and the first terminal of the inductor LD2 are connected to each other. The second terminal of the inductor LD2 is connected to the positive output terminal Vou+ of the voltage conversion circuit 121. The control terminals of the switches SD1 and SD2 are connected to the control circuit 122. When the Cuk circuit 314 is working, the control circuit 122 sends PWM signals to the switches SD1 and SD2 to control the on and off of the switches SD1 and SD2. When the switch SD1 is on and the switch SD2 is off, the current flowing through the inductors LD1 and LD2 increases in a positive direction, and the energy at the input terminal of the voltage conversion circuit 121 can be transferred to the inductors LD1 and LD2. When the switch SD1 is off and the switch SD2 is on, the current flowing through the inductors LD1 and LD2 decreases in a positive direction, and the energy of the inductors LD1 and LD2 can be transferred to the load 200 and the capacitor C9 to supply power to the load 200. Therefore, the switch SD1 can be used as an energy storage switch component, the switch SD2 can be used as an energy transfer switch component, and the inductors LD1 and LD2 can be used as the energy storage magnetic elements for charging and discharging.

[0069] Fig. 3e is another circuit topology of the voltage conversion circuit in the embodiment of the present application. Referring to Fig. 3e, the voltage conversion circuit 121 can be configured as a Buck-Boost circuit 315, which includes switches SE1, SE2, SE3, SE4 and an inductor LE. The first terminal of the switch SE1 is connected to the positive input terminal Vin+ of the voltage conversion circuit 121, the first terminal of the switch SE2 is connected to the negative input terminal Vin- of the voltage conversion circuit 121, the first terminal of the inductor LE, the second terminal of the switch SE1 and the second terminal of the switch SE2 are connected to each other, the second terminal of the inductor LE, the second terminal of the switch SE3 and the second terminal of the switch SE4 are connected to each other, the first terminal of the switch SE3 is connected to the positive output terminal Vou+ of the voltage conversion circuit 121, and the first terminal of the switch SE4 is connected to the negative output terminal Vou- of the voltage conversion circuit 121. Moreover, the control terminals of the switches SE1-SE4 are connected to the control circuit 122, and the control circuit 122 sends PWM signals to the switches SE1-SE4 to control the conduction and disconnection of the switches SE1-SE4 when the Buck-Boost circuit 315 is working. When the switches SE1 and SE4 are turned on, the switches SE2 and SE3 are turned off, the current flowing through the inductor LE increases in a positive direction, and the energy at the input terminal of the voltage conversion circuit 121 can be transferred to the inductor LE. When the switches SE2 and SE3 are turned on, the switches SE1 and SE4 are turned off, the current flowing through the inductor LE decreases in a positive direction, and the energy of the inductor LE can be transferred to the electrical device 200 and the capacitor C9 to supply power to the electrical device 200. Therefore, the switches SE1 and SE4 can be used as energy storage switch components, the switches SE2 and SE3 can be used as energy transmission switch components, and the inductor LE can be used as an energy storage magnetic element for charging and discharging in the voltage conversion circuit. It can be understood that the switches SE1 and SE4 can be turned on at the same phase or turned on at different phases, and the switches SE2 and SE3 can be turned on at the same phase or turned on at different phases.

[0070] Fig. 3f is another circuit topology of the voltage conversion circuit in the embodiment of the present application. Referring to Fig. 3f, the voltage conversion circuit 121 can be configured as a half-bridge-full-wave circuit 316, which includes switches SF1, SF2, SF3, SF4, capacitors CF1, CF2, CF3, an inductor LF, and a transformer TF. The first terminal of the switch SF1 and the first terminal of the capacitor CF1 are both connected to the positive input terminal Vin+ of the voltage conversion circuit 121. The first terminal of the switch SF2 and the first terminal of the capacitor CF2 are both connected to the negative input terminal Vin- of the voltage conversion circuit 121. The second terminal of the switch SF1, the second terminal of the switch SF2, and the first terminal of the primary winding of the transformer TF are connected to each other. The second terminal of the capacitor CF1, the second terminal of the capacitor CF2, and the second terminal of the primary winding of the transformer TF are connected to each other. The first terminal of the switch SF3 is connected to the first terminal of the secondary winding of the transformer TF. The first terminal of the switch SF4 is connected to the second terminal of the secondary winding of the transformer TF. The second terminal of the switch SF3, the second terminal of the switch SF4, and the first terminal of the inductor LF are connected to each other. The second terminal of the inductor LF and the first terminal of the capacitor CF3 are both connected to the positive output terminal Vou+ of the voltage conversion circuit 121. The middle tap of the secondary winding of the transformer TF and the second terminal of the capacitor CF3 are connected to the negative output terminal Vou- of the voltage conversion circuit 121. The control terminals of the switches SF1-SF4 are connected to the control circuit 122. When the half-bridge-full-wave circuit 316 is working, the control circuit 122 sends PWM signals to the switches SF1-SF4 to control the conduction and disconnection of the switches SF1-SF4. When the switches SF1 and SF2 are conducting and the switches SF3 and SF4 are disconnected, the energy at the input terminal of the voltage conversion circuit 121 can be transferred to the transformer TF, and the current in the primary winding of the transformer TF can be increased in a positive direction. The primary winding of the transformer TF and the secondary winding of the transformer TF are coupled to each other, so that the energy can be coupled to the secondary winding of the transformer TF, thereby causing the secondary winding to generate a current and increasing the current in a positive direction. When the switches SF3 and SF4 are conducting and the switches SF1 and SF2 are disconnected, the current in the secondary winding can be decreased in a positive direction, and the energy of the transformer TF can be transferred to the electrical device 200 and the capacitor C9 to supply power to the electrical device 200. Therefore, the switches SF1 and SF2 can be used as energy storage switch components, the switches SF3 and SF4 can be used as energy transmission switch components, and the transformer TF can be used as an energy storage magnetic element for charging and discharging in the voltage conversion circuit. It can be understood that the switches SF1 and SF2 can be conducting at the same phase or at different phases, and the switches SF3 and SF4 can also be conducting at the same phase or at different phases.

[0071] Fig. 3g is another circuit topology of the voltage conversion circuit in the embodiment of the present application. Referring to Fig. 3g, the voltage conversion circuit 121 can be provided as a full-bridge-full-wave circuit 317, which includes switches SG1, SG2, SG3, SG4, SG5, SG6, capacitors CG1, CG2, an inductor LG, and a transformer TG. The first end of the switch SG1 and the first end of the switch SG3 are connected to the positive input terminal Vin+ of the voltage conversion circuit 121, and the first end of the switch SG2 and the first end of the switch SG4 are connected to the negative input terminal Vin- of the voltage conversion circuit 121. The second end of the switch SG1, the second end of the switch SG2, and the first end of the capacitor CG1 are connected to each other, and the second end of the capacitor CG1 is connected to the second end of the primary winding of the transformer TG. The second end of the switch SG3, the second end of the switch SG4, and the first end of the primary winding of the transformer TG are connected to each other. The first end of the switch SG5 is connected to the first end of the secondary winding of the transformer TG, and the first end of the switch SG6 is connected to the second end of the secondary winding of the transformer TG. The second end of the switch SG5, the second end of the switch SG6, and the first end of the capacitor CG2 are connected to the negative output terminal Vou- of the voltage conversion circuit 121. The middle tap of the secondary winding of the transformer TG is connected to the first end of the inductor LG, and the second end of the inductor LG and the second end of the capacitor CG2 are connected to the positive output terminal Vou+ of the voltage conversion circuit 121. Furthermore, the control terminals of the switches SG1-SG6 are connected to the control circuit 122. When the full-bridge-full-wave circuit 317 is working, the control circuit 122 sends PWM signals to the switches SG1-SG6 to control the conduction and disconnection of the switches SG1-SG6. When the switches SG1, SG4 are turned on, the switches SG2, SG3, SG5, SG6 are disconnected, the current of the primary winding increases positively, and the energy of the input terminal of the voltage conversion circuit 121 is transmitted to the transformer TG. The primary winding and the secondary winding of the transformer TG are coupled to each other, so that the secondary winding generates a current and the current increases positively. Then, the switches SG5, SG6 are turned on, and the switches SG1, SG2, SG3, SG4 are disconnected. The current of the secondary winding decreases positively, and the energy of the transformer TG is transmitted to the electrical equipment 200 and the capacitor C9 to supply power to the electrical equipment 200. Then, when the switches SG2, SG3 are turned on, the switches SG1, SG4, SG5, SG6 are disconnected, the current of the primary winding increases positively again, and the energy of the input terminal of the voltage conversion circuit 121 is transmitted to the transformer TG. The primary winding and the secondary winding of the transformer TG are coupled to each other, so that the secondary winding generates a current and the current increases positively. Then, the switches SG5, SG6 are turned on, and the switches SG1, SG2, SG3, SG4 are disconnected. The current of the secondary winding decreases positively, and the energy of the transformer TG is transmitted to the electrical equipment 200 and the capacitor C9 to supply power to the electrical equipment 200.Therefore, the switches SG1-SG4 can be used as energy storage switch components, the switches SG5, SG6 can be used as energy transmission switch components, and the transformer TG can be used as an energy storage magnetic element for charging and discharging in the voltage conversion circuit. It can be understood that the switches SG1, SG4 can be simultaneously turned on in phase or simultaneously turned on out of phase, the switches SG2, SG3 can also be simultaneously turned on in phase or simultaneously turned on out of phase, and the switches SG5, SG6 can also be simultaneously turned on in phase or simultaneously turned on out of phase.

[0072] Fig. 3h is another circuit topology of the voltage conversion circuit in the embodiment of the present application. Referring to Fig. 3h, the voltage conversion circuit 121 can be provided as a full-bridge-full-bridge circuit 318, wherein the full-bridge-full-bridge circuit 318 comprises switches SH1, SH2, SH3, SH4, SH5, SH6, SH7, SH8, a capacitor CH1 and a transformer TH, the first end of the switch SH1 and the first end of the switch SH3 are connected with the positive input terminal Vin+ of the voltage conversion circuit 121, the first end of the switch SH2 and the first end of the switch SH4 are connected with the negative input terminal Vin- of the voltage conversion circuit 121, the second end of the switch SH1, the second end of the switch SH2 and the first end of the capacitor CH are connected with each other, the second end of the capacitor CH is connected with the first end of the primary winding of the transformer TH, the second end of the switch SH3, the second end of the switch SH4 and the second end of the primary winding of the transformer TH are connected with each other, the first end of the switch SH5 and the first end of the switch SH7 are connected with the positive output terminal Vou+ of the voltage conversion circuit 121, the first end of the switch SH6 and the first end of the switch SH8 are connected with the negative output terminal Vou- of the voltage conversion circuit 121, the second end of the switch SH5 and the second end of the switch SH6 are connected with the first end of the secondary winding of the transformer TH, the second end of the switch SH7 and the second end of the switch SH8 are connected with the second end of the secondary winding of the transformer TH. Moreover, the control terminals of the switches SH1-SH8 are connected with the control circuit 122, and the control circuit 122 sends PWM signals to the switches SH1-SH8 to control the on and off of the switches SH1-SH8 when the full-bridge-full-bridge circuit 318 works. Wherein, the switches SH1 and SH4 are on, the switches SH2, SH3 and SH5-SH8 are off, the current of the primary winding of the transformer TH increases positively, and the energy of the input terminal of the voltage conversion circuit 121 can be transmitted to the transformer TH. The primary winding and the secondary winding of the transformer TH are coupled with each other, so that the current of the secondary winding is generated and increases positively. Then, the switches SH5 and SH8 are on, the switches SH1-SH4, SH6 and SH7 are off, the current of the secondary winding decreases positively, and the energy of the transformer TH can be transmitted to the electric device 200 and the capacitor C9 to supply power for the electric device 200. Then, the switches SH2 and SH3 are on, the switches SH1, SH4 and SH5-SH8 are off, the current of the primary winding increases positively again, and the energy of the input terminal of the voltage conversion circuit 121 can be transmitted to the transformer TH. The primary winding and the secondary winding of the transformer TH are coupled with each other, so that the current of the secondary winding is generated and increases positively. Then, the switches SH6 and SH7 are on, the switches SH1-SH4, SH5 and SH8 are off, the current of the secondary winding decreases positively, and the energy of the transformer TH can be transmitted to the electric device 200 and the capacitor C9 to supply power for the electric device 200.Therefore, the switches SH1-SH4 can be used as the energy storage switch assembly, the switches SH5-SH8 can be used as the energy transmission switch assembly, and the transformer TH can be used as the energy storage magnetic element in the voltage conversion circuit. It should be understood that the switches SH1 and SH4 can be turned on at the same phase or turned on at the opposite phase, the switches SH2 and SH3 can be turned on at the same phase or turned on at the opposite phase, the switches SH5 and SH8 can be turned on at the same phase or turned on at the opposite phase, and the switches SH6 and SH7 can be turned on at the same phase or turned on at the opposite phase.

[0073] It should be noted that the switches in the embodiments of the present application can be one or more of various types of switching devices such as a relay, a metal oxide semiconductor field effect transistor (MOSFET), a bipolar junction transistor (BJT), an insulated gate bipolar transistor (IGBT), a silicon carbide (SiC) MOSFET, a GaN semiconductor device, a Schottky diode, etc. The embodiments of the present application do not list them one by one. Each switch can include a first end, a second end, and a control end, wherein the control end is used to control the on or off of the switch. When the switch is on, current can pass between the first end and the second end of the switch. When the switch is off, current cannot pass between the first end and the second end of the switch. Taking the MOSFET as an example, the control end of the switch is the gate, the first end of the switch can be the source, and the second end can be the drain, or the first end can be the drain, and the second end can be the source.

[0074] It should be understood that based on the above-mentioned topology, in some topologies of the voltage conversion circuit with a physical inductor, the physical inductor can be used as the energy storage magnetic element in the voltage conversion circuit, and in another topology of the voltage conversion circuit with a transformer, the physical inductor can not be provided, and the transformer can be used as the energy storage magnetic element in the voltage conversion circuit. In addition, the above is only an example of some topologies of the voltage conversion circuit, and in specific implementation, the topology of the voltage conversion circuit is not limited to the above-mentioned topologies provided by the embodiments of the present application, and can also be other topologies known to those skilled in the art. In addition, for the energy storage switch assembly, the energy transmission switch assembly, and the energy storage magnetic element in other topologies, the same can be applied by analogy, and details are not described herein. The working process of the switching power supply device in the embodiments of the present application is described below taking the topology shown in FIG. 3a as an example.

[0075] In practical applications, taking the power amplifier in the base station as an example, the power amplifier transmits radio frequency signals and communicates with the terminal device. However, the power amplifier transmits radio frequency signals more frequently in a part of the 24 hours, has a higher load rate, and consumes more energy. In another part of the 24 hours, the power amplifier transmits radio frequency signals less frequently, has a lower load rate, and consumes less energy. Based on this, in order to enable the voltage conversion circuit to work efficiently with low energy consumption, the mode of the voltage conversion circuit 121 can be controlled according to the size of the load rate of the power-using device 200. For example, one way of controlling the mode of the voltage conversion circuit 121 according to the size of the load rate of the power-using device 200 is as follows: by setting a second load rate threshold, the load rate of the power-using device 200 is compared with the second load rate threshold. When the load rate of the power-using device 200 is greater than the second load rate threshold, it indicates that the load rate of the power-using device 200 is high and the energy consumption is high. In order to meet the power supply demand of the power-using device 200, the voltage conversion circuit 121 can be controlled to work in the normal mode, so that the voltage conversion circuit 121 transmits more energy to the power-using device 200 side and ensures that the power-using device 200 works efficiently.

[0076] Specifically, when the voltage conversion circuit 121 works in the normal mode, the control circuit 122 can control the switches SA1 and SA2 to work in the third working state, and in the third working state, the switches SA1 and SA2 are complementary on. In specific implementation, the PWM signal output by the control circuit 122 to the voltage conversion circuit 121 has a switching frequency (i.e. the reciprocal of the switching period) and a duty cycle. Since the duty cycle represents how much energy is transmitted by the voltage conversion circuit 121 from the input end to the output end, i.e. the higher the duty cycle, the more energy the voltage conversion circuit 121 transmits, and vice versa, the lower the duty cycle, the less energy the voltage conversion circuit 121 transmits. Therefore, the on-off state of the switch in the voltage conversion circuit 121 can be adjusted by adjusting the duty cycle to adjust how much energy the voltage conversion circuit 121 transmits. Based on this, when the voltage conversion circuit works in the normal mode, the control circuit 122 can calculate the duty cycle D1 of the switch SA1 according to the average voltage of the capacitor C9 and the target voltage, send the PWM signal to the switches SA1 and SA2 based on the duty cycle D1, control the switches SA1 and SA2 to be complementary on, and provide sufficient energy for the power-using device 200. Moreover, since the switches SA1 and SA2 are complementary on, the duty cycle of the switch SA2 can be 1-D1.

[0077] Next, taking FIG. 3a as an example, the working process of the voltage conversion circuit 121 when working in the normal mode is described in detail in combination with FIG. 4a. FIG. 4a is a signal timing diagram of the voltage conversion circuit in the normal mode in the embodiment of the application. Wherein, P SA1 represents the PWM signal output by the control circuit 122 to the switch SA1, PSA2 PWM signal outputted by the control circuit 122 to the switch SA2, i LA represents the current flowing through the inductor LA, T1, T2, T3, T4 represent four continuous switch periods. Each switch period T1-T4 includes a t11 stage and a t12 stage. Specifically, in the t11 stage, the PWM signal P SA1 controls the switch SA1 to be turned on, the PWM signal P SA2 controls the switch SA2 to be turned off, the inductor LA is charged, and the current i LA increases in a positive direction. In the t12 stage, the PWM signal P SA1 controls the switch SA1 to be turned off, the PWM signal P SA2 controls the switch SA2 to be turned on, the inductor LA is discharged, and the current i LA decreases in a positive direction. In the following switch period, the working process of the t11 stage and the t12 stage is repeated. In addition, in the present application, the current i LA is positive, and represents the current i LA flows into the positive input terminal of the voltage conversion circuit 121, and then flows through the positive input terminal of the voltage conversion circuit 121 and into the inductor LA.

[0078] In order to avoid directly controlling the switch SA1 and the switch SA2 to be turned on complementarily, which causes the voltage ripple of the output terminal of the voltage conversion circuit 121 to be large, in some embodiments of the present application, the process of controlling the switch SA1 and the switch SA2 to be turned on complementarily in the third working state can include: in at least two switch periods, the turn-on duration of the switch SA1 and the turn-on duration of the switch SA2 are sequentially increased until the switch SA1 and the switch SA2 are turned on complementarily. The working process of the voltage conversion circuit 121 when working in the normal mode is described in detail in combination with FIG. 4b. In FIG. 4b, P SA1 represents the PWM signal outputted by the control circuit 122 to the switch SA1, P SA2The PWM signal outputted by the representative control circuit 122 to the switch SA2 is represented by T1, T2, T3, T4, which represent four continuous switch periods. In the switch period T4, the switch SA1 and the switch SA2 are complementary on. In the switch period T1, the on duration of the switch SA1 is ta1, in the switch period T2, the on duration of the switch SA1 is ta2, in the switch period T3, the on duration of the switch SA1 is ta3, and in the switch period T4, the on duration of the switch SA1 is ta4, and ta1<ta2<ta3<ta4. In the switch period T1, the on duration of the switch SA2 is tb1, in the switch period T2, the on duration of the switch SA2 is tb2, in the switch period T3, the on duration of the switch SA2 is tb3, and in the switch period T4, the on duration of the switch SA2 is tb4, and tb1<tb2<tb3<tb4. Then, the working process of the switch period T4 is repeated.

[0079] In actual application, the power consumed by the electrical equipment 200 is not always large, but sometimes small. Therefore, according to the size of the load rate of the electrical equipment 200, another mode of mode control of the voltage conversion circuit 121 is that the first load rate threshold can be set, and the first load rate threshold is smaller than the second load rate threshold. Based on this, the load rate of the electrical equipment 200 can be compared with the first load rate threshold. When the load rate of the electrical equipment 200 is smaller than or equal to the first load rate threshold, it can be indicated that the load rate of the electrical equipment 200 is low, and the power consumed is small. In actual application, during the process that the energy at the input end of the voltage conversion circuit 121 is transmitted to the output end of the voltage conversion circuit 121, the current on the inductor LA will increase positively when the switch SA1 is turned on, and will decrease positively when the switch SA2 is turned on. When the current is negative, it indicates that the energy is backflowed, that is, the energy stored in the capacitor C9 (or called the energy on the electrical equipment 200 side) is transmitted to the inductor LA, resulting in energy waste. For example, if the switch SA1 and the switch SA2 continue to be controlled to work in the third working state, when the switch SA1 is turned on, the energy is transmitted from the input end of the voltage conversion circuit 121 to the output end of the voltage conversion circuit 121, and the energy will be accumulated on the capacitor C9. When the switch SA2 is turned on, the energy is also transmitted from the input end of the voltage conversion circuit 121 to the output end of the voltage conversion circuit 121 at the beginning, however, when the load rate of the electrical equipment 200 is smaller than or equal to the first load rate threshold, the electrical equipment 200 consumes less energy and cannot completely consume the energy transmitted by the voltage conversion circuit 121. For example, the electrical equipment 200 only needs to consume 1 part of energy, but the voltage conversion circuit 121 totally transmits 5 parts of energy to the capacitor C9, of which 1 part of energy is consumed by the electrical equipment 200, and the remaining 4 parts of energy cannot be consumed. In this way, when the switch SA2 is turned on, the 4 parts of energy stored in the capacitor C9 will backflow to the inductor LA, which is embodied by the reverse increase of the current of the inductor LA, thereby resulting in energy waste. Therefore, in order to improve the problem of energy waste, when the load rate of the electrical equipment 200 is smaller than or equal to the first load rate threshold, the control circuit 122 can control the voltage conversion circuit 121 to work in the light load mode, so as to realize the low-energy and high-efficiency working of the voltage conversion circuit 121.

[0080] Exemplarily, when the voltage conversion circuit 121 works in the light load mode, the control circuit 122 can control the working states of the switch SA1 and the switch SA2 according to the size relationship between the average voltage of the capacitor C9 and the target voltage. For example, when the average voltage of the capacitor C9 decreases to be less than or equal to the target voltage, the control circuit 122 can control the switch SA1 and the switch SA2 to work in the first working state. Specifically, in the first working state, the switch SA1 and the switch SA2 are sequentially turned on, that is, first, the switch SA1 is turned on, the switch SA2 is turned off, the current flowing through the inductor LA increases in a positive direction, and the energy at the input end of the voltage conversion circuit 121 is transferred to the side of the electrical equipment 200 to charge the capacitor C9. Then, the switch SA2 is turned on, the switch SA1 is turned off, the current flowing through the inductor LA decreases in a positive direction, and the energy at the input end of the voltage conversion circuit 121 is also transferred to the side of the electrical equipment 200, so that the energy at the input end of the voltage conversion circuit 121 can be transferred to the electrical equipment 200 and the capacitor C9 through the current flowing through the inductor LA. Moreover, when the current flowing through the inductor LA decreases in a positive direction to be close to zero, the switch SA1 and the switch SA2 can be both turned off to avoid the energy stored in the capacitor C9 from flowing back. Based on this, when the switch SA1 and the switch SA2 work in the first working state, the direction of energy transfer is from the input end of the voltage conversion circuit 121 to the output end of the voltage conversion circuit 121, so that energy backflow can be avoided, energy waste can be reduced, and thus the loss can be reduced and the conversion efficiency of the voltage conversion circuit 121 can be improved.

[0081] Moreover, since the capacitor C9 is connected in parallel with the output end of the voltage conversion circuit 121, during the energy transfer process of the voltage conversion circuit 121, the capacitor C9 can be charged, so that the voltage on the capacitor C9 gradually increases. When the average voltage of the capacitor C9 is greater than the target voltage, it indicates that the energy transferred by the voltage conversion circuit 121 to the capacitor C9 is sufficient to power the electrical equipment 200, and the control circuit 122 can control the switch SA1 and the switch SA2 to be both turned off to temporarily stop the energy transfer process of the voltage conversion circuit 121, so that the loss can be reduced and the capacitor C9 can be prevented from overshooting. Moreover, since the capacitor C9 has the function of storing energy, when the switch SA1 and the switch SA2 are both turned off, the electrical equipment 200 can be powered by the energy stored in the capacitor C9 to avoid power failure of the electrical equipment 200.

[0082] Based on this, when the load rate of the electrical equipment 200 is less than or equal to the first load rate threshold, the voltage conversion circuit 121 is controlled in the light load mode, so that the switch power supply device can work more efficiently.

[0083] It is worth mentioning that the current flowing through the inductor LA close to zero can be that the difference between the value of the current flowing through the inductor LA and zero is between ±ΔI. Wherein, ΔI can be equal to 0, or ΔI can not be equal to 0, but a value close to zero, for example, ΔI can be 0.001, -0.01, 0.1, 0.3A, etc. Those skilled in the art can understand that the purpose of detecting whether the current flowing through the inductor LA is close to zero is to determine when to switch the switch SA2 from on to off, so that the switches SA1 and SA2 are both off, to avoid the current flowing through the inductor LA reversing, and to avoid energy backflow. Therefore, it can be understood that in the actual process, those skilled in the art can set the specific value according to the control accuracy of the control circuit 122 or according to the needs of the actual application scene on the premise of meeting the purpose, which is not limited in this application.

[0084] In the embodiment of the application, the target voltage can be the rated voltage of the electrical equipment 200, the actual demand voltage of the electrical equipment 200, the rated voltage of the capacitor C9 or other voltages, which can be determined according to the actual application scene, which is not limited here. And the average voltage of the capacitor C9 can be the average voltage of the capacitor C9 in a period of time. For example, a voltage sampling circuit is provided in the switching power supply device, the voltage of the capacitor C9 in a period of time can be collected by the voltage sampling circuit, and the average value of the voltage in the period of time is calculated to obtain the average voltage of the capacitor C9. And the average voltage of the capacitor C9 is sent to the control circuit 122, so that the control circuit 122 can obtain the average voltage of the capacitor C9, so that the working state of the switch SA1 and the switch SA2 can be controlled according to the size relationship between the average voltage of the capacitor C9 and the target voltage.

[0085] And, the load of the electric device 200 can be or include the amount of data needed to be transmitted through the electric device 200 per unit time, then the load rate of the electric device 200 can also be called the utilization rate of the electric device 200, which can refer to the ratio of the amount of data needed to be transmitted through the electric device 200 per unit time to the maximum amount of data that the electric device 200 can transmit per unit time. As an example, when the load rate of the electric device 200 is in the interval [0, 2%], the load state of the electric device 200 is an idle state. When the load rate of the electric device 200 is in the interval (2%, 50%], the load state of the electric device 200 is a light load state. When the load rate of the electric device 200 is in the interval (50%, 75%], the load state of the electric device 200 is a regular state. When the load rate of the electric device 200 is in the interval (75%, 100%], the load state of the electric device 200 is a heavy load state. Based on this, the first load rate threshold can be set to 2%, and the second load rate threshold can be set to 50%. In addition, the above first load rate threshold is set to 2% and the second load rate threshold is set to 50% is only an example, because the specific values of the first load rate threshold and the second load rate threshold required by different application scenarios are different, therefore the specific values of the first load rate threshold and the second load rate threshold can be determined according to the relationship that the second load rate threshold is greater than the first load rate threshold, and according to the actual application scenario, which is not limited here.

[0086] In addition, the above-mentioned voltage conversion circuit 121 is exemplified by taking the topology shown in Fig. 3a as an example. When the voltage conversion circuit 121 takes the topology shown in Fig. 3b, the current flowing through the energy storage magnetic element decreasing to near zero in the positive direction can be that the current flowing through the inductor LB decreases to near zero in the positive direction, and the control energy storage switch assembly and the energy transfer switch assembly being both off can be that the control switches SB1 and SB2 are both off. When the voltage conversion circuit 121 takes the topology shown in Fig. 3c, the current flowing through the energy storage magnetic element decreasing to near zero in the positive direction can be that the current flowing through the inductor LC decreases to near zero in the positive direction, and the control energy storage switch assembly and the energy transfer switch assembly being both off can be that the control switches SC1 and SC2 are both off. When the voltage conversion circuit 121 takes the topology shown in Fig. 3d, the current flowing through the energy storage magnetic element decreasing to near zero in the positive direction can be that the current flowing through the inductor LD1 decreases to near zero in the positive direction, and the control energy storage switch assembly and the energy transfer switch assembly being both off can be that the control switches SD1 and SD2 are both off. When the voltage conversion circuit 121 takes the topology shown in Fig. 3e, the current flowing through the energy storage magnetic element decreasing to near zero in the positive direction can be that the current flowing through the inductor LE decreases to near zero in the positive direction, and the control energy storage switch assembly and the energy transfer switch assembly being both off can be that the control switches SE1-SE4 are all off. When the voltage conversion circuit 121 takes the topology shown in Fig. 3f, the current flowing through the energy storage magnetic element decreasing to near zero in the positive direction can be that the current flowing through the secondary winding of the transformer TF decreases to near zero in the positive direction, and the control energy storage switch assembly and the energy transfer switch assembly being both off can be that the control switches SF1-SF4 are all off. When the voltage conversion circuit 121 takes the topology shown in Fig. 3g, the current flowing through the energy storage magnetic element decreasing to near zero in the positive direction can be that the current flowing through the secondary winding of the transformer TG decreases to near zero in the positive direction, and the control energy storage switch assembly and the energy transfer switch assembly being both off can be that the control switches SG1-SG6 are all off. When the voltage conversion circuit 121 takes the topology shown in Fig. 3h, the current flowing through the energy storage magnetic element decreasing to near zero in the positive direction can be that the current flowing through the secondary winding of the transformer TH decreases to near zero in the positive direction, and the control energy storage switch assembly and the energy transfer switch assembly being both off can be that the control switches SH1-SH8 are all off. Based on this, for the working process of the voltage conversion circuit 121 taking other topologies, it can be deduced accordingly, and will not be described here.

[0087] In a specific implementation, when the voltage conversion circuit 121 works in the light load mode, when the average voltage of the capacitor C9 is less than or equal to the target voltage, the control circuit 122 can calculate the duty ratio D2 corresponding to the switch SA1 according to the average voltage of the capacitor C9 and the target voltage, and output a PWM signal to the switch SA1 according to the duty ratio D2 to control the conduction and disconnection of the switch SA1. Therefore, the switch SA1 can be controlled without additional devices, and the hardware structure of the switching power supply device does not need to be additionally designed, thereby reducing the design cost. For example, D2 can be the same as or different from D1. For example, when the power consumption of the electrical equipment is low, the voltage conversion circuit 121 can deliver less energy, so that D2 is less than D1, so that the conduction time of the switch SA1 working in the first working state is less than the conduction time of the switch SA1 working in the third working state, thereby enabling the voltage conversion circuit 121 to work in low energy and high efficiency. Further, the value range of D1 is usually (1%, 100%], and the value range of D2 can be (5%, 10%] or (5%, 6%]. Therefore, the voltage conversion circuit 121 can deliver less energy in the light load mode than in the normal mode, thereby further achieving low energy and high efficiency.

[0088] In the embodiment of the present application, when the switch SA1 and the switch SA2 work in the first working state, during the conduction of the switch SA2, the switch SA2 and the switch SA1 can be controlled to be disconnected when the current flowing through the inductor LA decreases to near zero. Therefore, the energy transmission switch assembly can be controlled without additional devices, and the hardware structure of the switching power supply device does not need to be additionally designed, thereby reducing the design cost. In the first working state, the signal for controlling the switch SA2 to be disconnected can be obtained by detecting the current flowing through the inductor LA or by an algorithm, which will be described below.

[0089] The first mode: the current flowing through the inductor LA is detected, and according to the detection result, when the current flowing through the inductor LA is reduced to near zero in the positive direction, the switch SA1 and the switch SA2 are both turned off. For example, referring to FIG. 5, which is a schematic diagram of a circuit structure of a switching power supply device in an embodiment of the present application, the switching power supply device further includes a first sampling circuit 123 for detecting the current flowing through the inductor LA. For example, the first end of the inductor LA is connected in series with a second sampling resistor RA, so that the first end of the inductor LA is connected to the positive input terminal Vin+ and the negative output terminal Vou- of the voltage conversion circuit 121 through the second sampling resistor RA, and the first sampling circuit 123 is connected to both ends of the second sampling resistor RA, so that the current flowing through the inductor LA can be detected based on the second sampling resistor RA. In addition, the control circuit 122 can be directly wired or connected in communication with the first sampling circuit 123, so that the first sampling circuit 123 sends the detected current of the inductor LA to the control circuit 122, or the first sampling circuit 123 sends a data signal representing the detected current of the inductor LA to the control circuit 122. Based on this, for the process of turning off the switch SA1 and the switch SA2 when the current flowing through the inductor LA is near zero, the control circuit 122 can determine to turn off the switch SA1 and the switch SA2 when the current flowing through the inductor LA is detected to be near zero based on the information sent by the first sampling circuit 123, so as to ensure that the current flowing through the inductor LA is all in the positive direction, avoid energy backflow, and reduce loss. For example, the first sampling circuit 123 includes but is not limited to a Hall sensor or a current transformer. In addition, the control circuit 122 can also perform a series of protection operations based on the current detected by the first sampling circuit 123, to improve the reliability of the voltage conversion circuit.

[0090] The second mode: based on the voltage at the input terminal of the voltage conversion circuit 121, the voltage at the output terminal of the voltage conversion circuit 121, and the on duration of the switch SA1, the current flowing through the inductor LA is determined to be near zero by using an algorithm to control the switch SA1 and the switch SA2 to be turned off. For example, referring to FIG. 5, the control circuit 122 can obtain the on duration of the switch SA1 (i.e. the switching period*D2) through D2, and then combine the voltage at the input terminal of the voltage conversion circuit 121 and the voltage at the output terminal of the voltage conversion circuit 121 to calculate the required on duration of the switch SA2. Based on this, after the switch SA1 is turned off, the control circuit 122 can control the switch SA2 to be turned on according to the calculated on duration, so as to control the switch SA2 to be turned off when the current flowing through the inductor LA is near zero, ensure that the current flowing through the inductor LA is all in the positive direction, avoid energy backflow, and reduce loss.

[0091] In some examples, when the topology of the voltage conversion circuit 121 is the topology shown in FIG. 3a, the on duration FSA2 The following relationship can be satisfied: F SA2 = F SA1 * Vi / Vo, F SA1 represents the on duration of switch SA1, Vi represents the voltage at the input terminal of voltage conversion circuit 121, and Vo represents the voltage at the output terminal of voltage conversion circuit 121.

[0092] In yet another example, when the topology of voltage conversion circuit 121 is the topology shown in Fig. 3b, the on duration F SA2 The following relationship can be satisfied: F SA2 = F SA1 * Vi / (Vo - Vi).

[0093] In yet another example, when the topology of voltage conversion circuit 121 is the topology shown in Fig. 3f, the on duration F SA2 The following relationship can be satisfied: F SA2 = F SA1 * (2Vi / N) / (Vo - 2Vi / N). N represents the ratio of the number of turns of the primary winding to the number of turns of the secondary winding of transformer TF.

[0094] In yet another example, when the topology of voltage conversion circuit 121 is the topology shown in Fig. 3g, the on duration F SA2 The following relationship can be satisfied: F SA2 = F SA1 * (Vi / N) / (Vo - Vi / N). N represents the ratio of the number of turns of the primary winding to the number of turns of the secondary winding of transformer TG.

[0095] For other topologies of voltage conversion circuit 121, the on duration F SA2 The on duration of switch SA2 can be obtained by analogy, and is not described here.

[0096] Since the PWM signal is a periodic control signal, in some embodiments of the present application, when the voltage conversion circuit 121 works in the light load mode, the switch SA1 and the switch SA2 can work in one switching period or sequentially appearing multiple switching periods, so that in at least one switching period, the switch SA1 is turned on first and the switch SA2 is turned on later. For example, referring to FIG. 5 and FIG. 6a, which is a signal timing diagram of the voltage conversion circuit working in the light load mode in the embodiments of the present application, taking three switching periods T1, T2, T3 appearing sequentially as an example, the switching period T1 can include sequentially appearing first stage t1a and second stage t1b, and the switching period T2 can include sequentially appearing first stage t2a and second stage t2b. Wherein, the control circuit 122 sends the PWM signal P SA1 to the switch SA1 and the PWM signal P SA2 to the switch SA2, based on which, in the first stage t1a, the PWM signal P SA1 controls the switch SA1 to be turned on, the PWM signal P SA2 controls the switch SA2 to be turned off, the inductor LA is charged and the current i LA flowing through the inductor LA increases positively, so that the energy at the input end of the voltage conversion circuit 121 can be transferred to the inductor LA. Then, the PWM signal P SA2 controls the switch SA2 to be turned on, the PWM signal P SA1 controls the switch SA1 to be turned off, the inductor LA is discharged, and the current i LA flowing through the inductor LA decreases positively, and when the current i LA flowing through the inductor LA decreases to near zero, the control PWM signal P SA2 controls the switch SA2 to be turned off, so that the current i LA flowing through the inductor LA is all positive, and the energy of the inductor LA is transferred to the electrical equipment and the capacitor C9, realizing one-time energy transfer and supplementing the energy of the electrical equipment 200 and the capacitor C9. In the second stage t1b, the PWM signal P SA1 controls the switch SA1 to be turned off, and the PWM signal P SA2 controls the switch SA2 to be turned off. In the first stage t2a, the PWM signal P SA1 controls the switch SA1 to be turned on, the PWM signal P SA2 controls the switch SA2 to be turned off, the inductor LA is charged and the current i LA flowing through the inductor LA increases positively, so that the energy at the input end of the voltage conversion circuit 121 can be transferred to the inductor LA. Then, the PWM signal P SA2 controls the switch SA2 to be turned on, the PWM signal P SA1 controls the switch SA1 to be turned off, the inductor LA is discharged, and the current i LA flowing through the inductor LA decreases positively, and when the current iLA The forward direction is reduced to near zero, and the PWM signal P SA2 The control switch SA2 is turned off, and the current i LA All are forward directions, and the energy of the inductor LA is transmitted to the electrical device and the capacitor C9, realizing energy transmission again and supplementing the electrical device and the capacitor C9 with energy again. In the second stage t2b, the PWM signal P SA1 The control switch SA1 is turned off, and the PWM signal P SA2 The control switch SA2 is turned off. After the end of the first stage t2a of the switching cycle T2, it can be detected that the average voltage of the capacitor C9 is greater than the target voltage, and the control circuit 122 can control the control switch SA1 and the control switch SA2 to be directly turned off to close the energy transmission channel, so that the control switch SA1 and the control switch SA2 are both turned off in the switching cycle T3. In addition, in the switching cycles T1-T2, there is not only a time period in which the control switch SA1 and the control switch SA2 are both turned on, but also a time period in which the control switch SA1 and the control switch SA2 are both turned off, so that energy can be supplemented in a short time and the loss is further reduced. Moreover, the present application takes the example of the control switch SA1 and the control switch SA2 being both turned off in the switching cycle T3. The skilled person can know that when the energy stored in the capacitor C9 is less consumed by the electrical device 200 in the switching cycle T3, the average voltage of the capacitor C9 will continue to be greater than the target voltage, and in the case where the load rate of the electrical device 200 is less than or equal to the first load rate threshold, the control switch SA1 and the control switch SA2 can also be controlled to be turned off for one, two, three, four or more switching cycles, so as to further realize low-energy and high-efficiency operation.

[0097] Referring to FIG. 6a, in the first working state, the conduction time of the control switch SA1 and the control switch SA2 can be maintained unchanged respectively, and the energy is transmitted to the capacitor C9 to charge the capacitor C9, so that the average voltage of the capacitor C9 is greater than the target voltage. That is, t1 represents the conduction time of the control switch SA1 in the switching cycle T1, and t2 represents the conduction time of the control switch SA1 in the switching cycle T2. By making t1=t2, the conduction time of the control switch SA1 can be unchanged. Moreover, the conduction time t3 of the control switch SA2 in the switching cycle T1 and the conduction time t4 of the control switch SA2 in the switching cycle T2 also satisfy t3=t4. Thus, the control difficulty of the PWM signal can be reduced, and the performance requirement of the control circuit 122 will not be particularly high, so that a control circuit with appropriate demand can be adopted, which is conducive to cost control.

[0098] However, in the first working state, when the on durations of the switches SA1 and SA2 remain unchanged, when it is determined that the average voltage of the capacitor C9 is greater than the target voltage, the control circuit 122 can directly control the switches SA1 and SA2 to be turned off, directly closing the energy transmission channel. However, this can cause the energy in the capacitor C9 to suddenly change. Therefore, in some embodiments of the present application, the on durations of the switches SA1 and SA2 in at least two consecutive switching periods can be controlled to decrease in turn, so that, based on the on durations of the switches SA1 and SA2 decreasing in turn, the maximum current flowing through the inductor LA decreases in turn, so that the energy transmitted also decreases in turn, thereby gradually reducing the energy supplied to the capacitor C9, avoiding sudden changes in the output voltage, and improving the stability of the output voltage. Exemplarily, referring to FIG. 6b, which is another signal timing diagram of the voltage conversion circuit in a light load mode in an embodiment of the present application, taking three switching periods T1, T2, T3 appearing in turn as an example, t1 represents the on duration of the switch SA1 in the switching period T1, t2 represents the on duration of the switch SA1 in the switching period T2, by making t1 < t2, the on duration of the switch SA1 can be made to decrease in turn, and the maximum current flowing through the inductor can be made to decrease in turn. Moreover, the on duration t3 of the switch SA2 in the switching period T1 and the on duration t4 of the switch SA2 in the switching period T2 also satisfy t3 < t4. It can be understood that, in the inverting Buck-Boost circuit, the case of t1 < t3 and t2 < t4 can occur. In other topologies, the relationship between t1 and t3 and the relationship between t2 and t4 can be determined according to the actual topology, which is not limited herein. Moreover, the on durations of the switches SA1 and SA2 in at least two consecutive switching periods can be controlled to decrease in turn in two, three, four or more consecutive switching periods, which is not limited herein.

[0099] In some other embodiments of the present application, when the voltage conversion circuit 121 works in the light load mode, the switches SA1 and SA2 can also be controlled in a control phase-based manner instead of a switching period-based manner. For example, referring to FIG. 7, which is another signal timing diagram of the voltage conversion circuit in a light load mode in an embodiment of the present application, taking three control phases WZ1, WZ2, WZ3 appearing in turn as an example. In the control phase WZ1, first, the PWM signal P SA1 The switch SA1 is controlled to be turned on, the inductor LA is charged, and the current i LA increases in a forward direction. Then, the PWM signal P SA2 The switch SA2 is controlled to be turned on, the inductor LA is discharged, and the current i LA decreases in a forward direction, and the current i LABefore the positive signal decreases to zero or zero, control the PWM signal P. SA2 Control switch SA2 is open, causing the current i flowing through inductor LA to... LA All are positive. In the control phase WZ2, firstly, the PWM signal P... SA1 When control switch SA1 is turned on, inductor LA is charged and the current i flowing through inductor LA is... LA It increases positively. Afterwards, the PWM signal P... SA2 Control switch SA2 is turned on, inductor LA is discharged, and the current i flowing through inductor LA... LA The positive direction decreases, and the current i flowing through the inductor LA decreases. LA Before the positive signal decreases to zero or zero, control the PWM signal P. SA2 Control switch SA2 is open, causing the current i flowing through inductor LA to... LA All are positive. Therefore, the operation of control phase WZ1 can be the same as that of phase t1a, and the operation of control phase WZ2 can be the same as that of phase t2a. There are no phases t1b and t2b. After control phases WZ1 and WZ2, the average voltage of capacitor C9 is greater than or equal to the target voltage, and control phase WZ3 begins, with the PWM signal P... SA1 Control switch SA1 is open, PWM signal P SA2 The control switch SA2 is turned off, so that the current flowing through the inductor LA is zero.

[0100] In some embodiments of the present application, after the switch SA1 and the switch SA2 enter the second working state for a predetermined length of time, i.e., after the switch SA1 and the switch SA2 are both disconnected for a predetermined length of time, the mode control of the voltage conversion circuit 121 can be performed again according to the size of the load rate of the electrical equipment 200, so as to realize the cyclic control of the mode of the voltage conversion circuit 121, so that the voltage conversion circuit 121 can work further low-energy and high-efficiently. Based on this, the mode control of the voltage conversion circuit 121 according to the size of the load rate of the electrical equipment 200 can include: when the load rate of the electrical equipment 200 is less than or equal to the first load rate threshold, the above-mentioned light load mode control is performed. When the load rate of the electrical equipment 200 is greater than the second load rate threshold, the above-mentioned normal mode control is performed. When the load rate of the electrical equipment 200 is greater than the first load rate threshold and less than or equal to the second load rate threshold, the mode of the voltage conversion circuit 121 is controlled to be the same as the previous mode, for example, the mode of the voltage conversion circuit 121 in the next switching cycle is controlled to be the same as the mode in the previous switching cycle. When the mode of the voltage conversion circuit 121 in the previous switching cycle is the normal mode, then the mode of the voltage conversion circuit 121 in the next switching cycle is also the normal mode. Or, when the mode of the voltage conversion circuit 121 in the previous switching cycle is the light load mode, then the mode of the voltage conversion circuit 121 in the next switching cycle is also the light load mode. By setting in this way, when the load rate is between the first load rate threshold and the second load rate threshold, the working of the voltage conversion circuit 121 is controlled based on the previous mode, which can reduce the ripple of the output voltage of the voltage conversion circuit 121 caused by mode conversion, and improve the stability of the output voltage.

[0101] And, when the first load rate threshold and the second load rate threshold are equal, due to the limitation of sampling accuracy, the mode of the voltage conversion circuit can be controlled to switch all the time, causing the output voltage of the voltage conversion circuit to oscillate. For example, if the first load rate threshold and the second load rate threshold are both 2, and the actual load rate of the electrical device is 2, due to the sampling accuracy of ±0.05, the collected load rate of the electrical device can be 2.05 or 1.95, and when the collected load rate of the electrical device is 2.05, the voltage conversion circuit is controlled in the normal mode. When the collected load rate of the electrical device is 1.95, the voltage conversion circuit is controlled in the light load mode. This will cause the voltage conversion circuit to frequently switch between the light load mode and the normal mode, causing the output voltage of the voltage conversion circuit to oscillate. Therefore, in the embodiments of the present application, the second load rate threshold is greater than the first load rate threshold. If the first load rate threshold is 1.5 and the second load rate threshold is 2.5, the actual load rate of the electrical device is 2, and the sampling accuracy is ±0.05, then the collected load rate of the electrical device can be 2.05 or 1.95. When the collected load rate of the electrical device is 2.05 or 1.95, the voltage conversion circuit can be controlled based on the last mode, which can reduce the ripple of the output voltage of the voltage conversion circuit and improve the stability of the output voltage.

[0102] It is worth mentioning that for the predetermined time length, the skilled person in the art can select a suitable value based on performance needs (such as the ripple of the output voltage of the voltage conversion circuit 121) and some cost considerations. For example, the predetermined time length can be set to 0.1-1000 switching periods. In actual application, if the predetermined time length is too short, after the switches SA1 and SA2 are both disconnected in the second working state, the process of controlling the mode of the voltage conversion circuit 121 according to the size of the load rate of the electrical device 200 is performed soon. In order to meet the performance requirements of this mode, a controller with good performance is needed, resulting in increased cost. If the predetermined time length is too long, after the switches SA1 and SA2 are both disconnected in the second working state, the process of controlling the mode of the voltage conversion circuit 121 according to the size of the load rate of the electrical device 200 is performed after a long wait. This will cause the ripple of the output voltage of the voltage conversion circuit 121 to be too large, affecting the performance. Therefore, considering the influence of cost and performance, in the embodiments of the present application, the first set time length is set to 5-20 switching periods to balance the influence of cost and performance. For example, the first set time length can be 5, 7, 9, 10, 12, 15, 18 or 20 switching periods, etc., which is not limited here.

[0103] Further, one or more voltage conversion circuits 121 can be provided in the switching power supply device. When multiple voltage conversion circuits 121 are provided, the input ends of the multiple voltage conversion circuits 121 are connected in parallel, and the output ends of the multiple voltage conversion circuits 121 are connected in parallel. For example, referring to FIG. 8, which is a schematic diagram of another circuit structure of the switching power supply device according to an embodiment of the present application, two voltage conversion circuits 121a and 121b are provided in the switching power supply device, the input ends of the voltage conversion circuits 121a and 121b are connected in parallel, and the output ends of the voltage conversion circuits 121a and 121b are also connected in parallel. The control circuit 122 is connected to the voltage conversion circuits 121a and 121b, and can control the voltage conversion circuits 121a and 121b to work in the above-mentioned mode according to an embodiment of the present application. Alternatively, the control circuit 122 can control the voltage conversion circuit 121a to work in the above-mentioned working process according to an embodiment of the present application, and control the voltage conversion circuit 121b to stop working, when the load rate of the electric device is less than or equal to the third load rate threshold, so that only part of the voltage conversion circuits 121 are used to supply power to the electric device, and the loss is further reduced. Thus, the third load rate threshold can be used to determine whether all the voltage conversion circuits 121 are used to realize multi-phase working, or part of the voltage conversion circuits 121 are used to realize partial-phase working, or one voltage conversion circuit 121 is used to realize single-phase working. As an example, the third load rate threshold can be set to 75% based on the above description. Of course, since the specific value of the third load rate threshold varies in different application scenarios, the specific value of the third load rate threshold can be determined according to the relationship that the third load rate threshold is greater than the second load rate threshold, which is greater than the first load rate threshold, and according to the actual application scenario, which is not limited herein.

[0104] In a specific implementation, the load rate of the electric device and the size relationship among the first load rate threshold, the second load rate threshold, and the third load rate threshold can have multiple determination manners, which are exemplified as follows.

[0105] The first determination manner: the load rate of the electrical equipment and the size relationship among the first load rate threshold, the second load rate threshold and the third load rate threshold can be determined based on the size relationship between the current at the input end of the electrical equipment and the load current threshold. The load current threshold can include the first load current threshold, the second load current threshold and the third load current threshold which increase in value in sequence. When the current at the input end of the electrical equipment is less than or equal to the first load current threshold, it is determined that the load rate of the electrical equipment is less than or equal to the first load rate threshold. When the current at the input end of the electrical equipment is greater than the first load current threshold and less than or equal to the second load current threshold, it is determined that the load rate of the electrical equipment is greater than the first load rate threshold and less than or equal to the second load rate threshold. When the current at the input end of the electrical equipment is greater than the third load current threshold, it is determined that the load rate of the electrical equipment is greater than the third load rate threshold. It can be understood that the specific values of the first load current threshold, the second load current threshold and the third load current threshold can be determined according to the requirements of specific application scenarios, which are not limited herein.

[0106] In order to obtain the current at the input end of the electrical equipment, the second sampling circuit can be arranged in the switching power supply device to detect the current at the input end of the electrical equipment. For example, referring to FIG. 9, which is another circuit structure schematic diagram of the switching power supply device in the embodiment of the present application, the switching power supply device further includes a second sampling circuit 124, wherein the second sampling circuit 124 is connected between the output end of the voltage conversion circuit 121 and the electrical equipment 200. Further, when the output filter circuit 140 is arranged, the second sampling circuit 124 is connected between the output filter circuit 140 and the electrical equipment 200. Based on this, the second sampling circuit 124 can detect the current at the input end of the electrical equipment 200, so that the control circuit 122 can determine the size relationship between the load rate of the electrical equipment and different load rate thresholds based on the current at the input end of the electrical equipment detected by the second sampling circuit. As an example, the second sampling circuit 124 can include an operational amplifier OP and a first sampling resistor RC, and the first sampling resistor RC is connected between the output end of the voltage conversion circuit 121 and the input end of the electrical equipment 200. The input end of the operational amplifier OP is connected to both ends of the first sampling resistor RC, and the output end of the operational amplifier OP is connected to the control circuit 122. Because the current at the input end of the electrical equipment 200 suddenly increases, the voltage difference between both ends of the first sampling resistor RC will increase, and the signal output by the operational amplifier OP will change. Based on this arrangement, a simple structure can be used, i.e., the control circuit 122 can identify the current at the input end of the electrical equipment 200 based on the signal output by the operational amplifier OP, and then determine the size relationship between the load rate of the electrical equipment 200 and different load rate thresholds according to the identified current at the input end of the electrical equipment 200.

[0107] In a specific implementation, the first sampling resistor RC is connected between the positive output terminal Vou+ of the voltage conversion circuit 121 and the positive input terminal of the electrical device 200. Further, when the output filter circuit 140 is provided, in order to accurately detect the current at the input terminal of the electrical device 200, the first sampling resistor RC can be connected between the output filter circuit 140 and the input terminal of the electrical device 200. For example, the second terminal of the capacitor C10 and the second terminal of the filter inductor Lv3 are connected to each other and then connected to the positive input terminal of the electrical device 200 through the first sampling resistor RC.

[0108] The second determination manner: the load rate of the electrical device and the size relationship among the first load rate threshold, the second load rate threshold and the third load rate threshold can be determined based on the size relationship between the current flowing through the inductor LA and the magnetic element current threshold. The magnetic element current threshold can include the first magnetic element current threshold, the second magnetic element current threshold and the third magnetic element current threshold which are sequentially increased in value. When the current flowing through the inductor LA is less than or equal to the first magnetic element current threshold, it is determined that the load rate of the electrical device is less than or equal to the first load rate threshold. When the current flowing through the inductor LA is greater than the first magnetic element current threshold and less than or equal to the second magnetic element current threshold, it is determined that the load rate of the electrical device is greater than the first load rate threshold and less than or equal to the second load rate threshold. When the current flowing through the inductor LA is greater than the third magnetic element current threshold, it is determined that the load rate of the electrical device is greater than the third load rate threshold. It can be understood that the specific values of the first magnetic element current threshold, the second magnetic element current threshold and the third magnetic element current threshold can be determined according to the requirements of specific application scenarios, which are not limited herein.

[0109] Exemplarily, referring to FIG. 8, the control circuit 122 can identify the current flowing through the inductor LA based on the information sent by the first sampling circuit 123, and then determine the size relationship among the load rate of the electrical device and different load rate thresholds according to the size relationship between the current flowing through the inductor LA and the magnetic element current threshold described above.

[0110] The third determination manner: the control circuit 122 can also communicate with the electrical device 200. The control circuit 122 can determine the size relationship among the load rate of the electrical device and different load rate thresholds according to the trigger signal sent by the electrical device 200 directly to the control circuit 122.

[0111] Exemplarily, the power consuming device 200 can send a trigger signal to the control circuit 122 based on the amount of data it transmits. For example, the amount of data transmitted by the power consuming device 200 increases, indicating that the load rate thereof increases. Specifically, a data amount threshold value can be set, and the power consuming device 200 can compare the amount of data it transmits with the size of the data amount threshold value, and determine the size relationship between the load rate of the power consuming device and the first load rate threshold value, the second load rate threshold value and the third load rate threshold value according to the size relationship between the amount of data it transmits and the data amount threshold value. The data amount threshold value can include a first data amount threshold value, a second data amount threshold value and a third data amount threshold value which increase in value in sequence. When the amount of data transmitted by the power consuming device 200 is less than or equal to the first data amount threshold value, it is determined that the load rate of the power consuming device is less than or equal to the first load rate threshold value. When the amount of data transmitted by the power consuming device 200 is greater than the first data amount threshold value and less than or equal to the second data amount threshold value, it is determined that the load rate of the power consuming device is greater than the first load rate threshold value and less than or equal to the second load rate threshold value. When the amount of data transmitted by the power consuming device 200 is greater than the third data amount threshold value, it is determined that the load rate of the power consuming device is greater than the third load rate threshold value. It can be understood that the specific values of the first data amount threshold value, the second data amount threshold value and the third data amount threshold value can be determined according to the requirements of specific application scenarios, which are not limited herein.

[0112] The above merely illustrates the specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which shall be covered within the protection scope of the present application.

Claims

1. A switching power supply device, characterized by comprising: The switching power supply device comprises a voltage conversion circuit and a control circuit, an input end of the voltage conversion circuit is configured to receive an input voltage, an output end of the voltage conversion circuit is configured to be connected to an electrical device, and the output end of the voltage conversion circuit is further connected in parallel with a capacitor; The voltage conversion circuit comprises an energy storage magnetic device, an energy storage switching assembly, and an energy transmission switching assembly, the energy storage switching assembly and the energy transmission switching assembly are respectively connected to the energy storage magnetic device, the energy storage switching assembly is configured to transmit energy at the input end of the voltage conversion circuit to the energy storage magnetic device, and the energy transmission switching assembly is configured to transmit energy at the energy storage magnetic device to the electrical device and the capacitor; The control circuit is configured to: when the load rate of the electrical device is less than or equal to the first load rate threshold, perform light load mode control on the voltage conversion circuit, and the light load mode control comprises: when the average voltage of the capacitor is less than or equal to a target voltage, control the energy storage switching assembly and the energy transmission switching assembly to work in a first working state; wherein, in the first working state, the energy storage switching assembly is first turned on, and the energy transmission switching assembly is turned on later, so that the energy at the input end of the voltage conversion circuit is transmitted to the electrical device and the capacitor through the current flowing through the energy storage magnetic device, and during the process of turning on the energy transmission switching assembly, when the current flowing through the energy storage magnetic device approaches zero, the energy storage switching assembly and the energy transmission switching assembly are both turned off; when the average voltage of the capacitor is greater than the target voltage, control the energy storage switching assembly and the energy transmission switching assembly to work in a second working state, wherein, in the second working state, the energy storage switching assembly and the energy transmission switching assembly are kept off.

2. The switching power supply apparatus according to claim 1, wherein In the first working state, the turn-on time of the energy storage switching assembly and the energy transmission switching assembly in at least two consecutive switching periods decreases in turn.

3. The switching power supply device according to claim 1 or 2, wherein The control circuit is further configured to: after controlling the energy storage switching assembly and the energy transmission switching assembly to be both off for a predetermined time length, perform mode control on the voltage conversion circuit according to the size of the load rate of the electrical device; wherein, the mode control on the voltage conversion circuit according to the size of the load rate of the electrical device comprises: when the load rate of the electrical device is less than or equal to the first load rate threshold, perform the light load mode control.

4. The switching power supply apparatus according to claim 3, wherein The predetermined time length is 5 switching periods to 20 switching periods.

5. The switching power supply device according to any one of claims 1 to 4, wherein The switching power supply device further comprises a first sampling circuit, the first sampling circuit is configured to detect the current flowing through the energy storage magnetic device, and the control circuit is connected to the first sampling circuit; The control of the energy storage switching assembly and the energy transmission switching assembly to be both off when the current flowing through the energy storage magnetic device approaches zero comprises: the control circuit controls the energy storage switching assembly and the energy transmission switching assembly to be both off when the first sampling circuit detects that the current flowing through the energy storage magnetic device approaches zero.

6. The switching power supply device according to any one of claims 1 to 4, wherein The control of the energy storage switching assembly and the energy transmission switching assembly to be both off when the current flowing through the energy storage magnetic device approaches zero comprises: The control circuit determines that the current flowing through the energy storage magnetic device is close to zero, and controls the energy storage switch assembly and the energy transmission switch assembly to be both turned off according to the voltage at the input end of the voltage conversion circuit, the voltage at the output end of the voltage conversion circuit, and the conduction duration of the energy storage switch assembly.

7. The switching power supply device according to any one of claims 1 to 6, wherein The voltage conversion circuit comprises an inductor, the energy storage switch assembly and the energy transmission switch assembly are connected to the inductor, the energy storage magnetic device is the inductor, and the current flowing through the energy storage magnetic device is the current flowing through the inductor. Alternatively, the voltage conversion circuit comprises a transformer, the energy storage switch assembly is connected to the primary winding of the transformer, the energy transmission switch assembly is connected to the secondary winding of the transformer, the energy storage magnetic device is the transformer, and the current flowing through the energy storage magnetic device is the current flowing through the secondary winding of the transformer. The mode control of the voltage conversion circuit according to the size of the load rate of the electrical equipment further comprises:

8. A switched mode power supply apparatus as claimed in any of claims 3 to 7, wherein, When the load rate of the electrical equipment is greater than a second load rate threshold, normal mode control is performed; the second load rate threshold is greater than the first load rate threshold. The normal mode control comprises: controlling the energy storage switch assembly and the energy transmission switch assembly to work in a third working state, wherein in the third working state, the energy storage switch assembly and the energy transmission switch assembly are complementary to be turned on. In the third working state, the energy storage switch assembly and the energy transmission switch assembly are complementary to be turned on, comprising:

9. The switching power supply apparatus according to claim 8, wherein In at least two switching periods, the conduction duration of the energy storage switch assembly and the energy transmission switch assembly is controlled to be sequentially increased until the energy storage switch assembly and the energy transmission switch assembly are complementary to be turned on. The mode control of the voltage conversion circuit according to the size of the load rate of the electrical equipment comprises:

10. A switched mode power supply apparatus as claimed in any of claims 3 to 9, wherein, When the load rate of the electrical equipment is greater than the first load rate threshold and less than or equal to the second load rate threshold, the mode of the voltage conversion circuit is controlled to be the same as the previous mode, and the second load rate threshold is greater than the first load rate threshold. The size relationship between the load rate of the electrical equipment and different load rate thresholds is determined based on the following manners:

11. The switching power supply device according to any one of claims 1 to 10, wherein The size relationship between the current detected by the first sampling circuit in the switching power supply device and a magnetic element current threshold; or The size relationship between the current at the input end of the electrical equipment detected by the second sampling circuit in the switching power supply device and a load current threshold; or The trigger signal sent by the electrical equipment. The second sampling circuit is arranged in the switching power supply, and the second sampling circuit is connected between the output end of the voltage conversion circuit and the electrical equipment.

12. The switching power supply apparatus according to claim 11, wherein The second sampling circuit comprises an operational amplifier and a first sampling resistor.

13. The switching power supply apparatus according to claim 12, wherein The first sampling resistor is connected between the output end of the voltage conversion circuit and the electrical equipment. The input end of the operational amplifier is connected to both ends of the first sampling resistor, and the output end of the operational amplifier is connected to the control circuit. The trigger signal is determined according to the amount of data transmitted by the electrical equipment.

14. The switching power supply apparatus of claim 11, wherein ​ 15. The switching power supply device according to any one of claims 1 to 14, wherein The switching power supply device comprises a plurality of voltage conversion circuits connected in parallel with each other; When the load rate of the electrical equipment is less than or equal to a third load rate threshold, the control circuit is further configured to: control a part of the plurality of voltage conversion circuits to work and control another part of the plurality of voltage conversion circuits to stop working, the third load rate threshold is greater than the second load rate threshold, and the second load rate threshold is greater than the first load rate threshold.

16. A power supply device, comprising: comprise: a power supply device and one or more switching power supply devices according to any one of claims 1-15; an input end of the power supply device is configured to receive a power supply voltage, an output end of the power supply device is connected with an input end of the switching power supply device, and an output end of the switching power supply device is configured to be connected with electrical equipment. comprise electrical equipment and one or more switching power supply devices according to any one of claims 1-15, and an output end of the switching power supply device is connected with the electrical equipment.

17. A communication device, characterized by ​

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