Soft switching circuit, control method thereof and power supply component

Abstract

The present application provides a soft switching circuit, including a switching voltage end, a main inductor, and a second voltage end, the switching voltage end being electrically connected to a first end of the main inductor, and the second voltage end being electrically connected to a second end of the main inductor, where the soft switching circuit further includes an auxiliary module and a first voltage end, the first end of the auxiliary module being electrically connected to the switching voltage end, and the second end of the auxiliary module being electrically connected to the first voltage end, where the auxiliary module is used to charge the auxiliary module using a first voltage input by the first voltage end to reduce a current flowing through the switching voltage end when the switching voltage end receives a first level signal, and the auxiliary module is further used to discharge the switching voltage end until the auxiliary module current crosses zero when the switching voltage end receives a second level signal, where the first level signal and the second level signal are different from each other. The present application further provides a power supply component including the soft switching circuit and a method for controlling the soft switching circuit.

Description

[Technical field]

[0001] [Cross reference] This application claims priority to a Chinese patent application bearing publication number CN202111669206.X and entitled "Soft switching circuit, control method thereof, and power supply component" filed with the State Intellectual Property Office on December 31, 2021, the entire contents of which are incorporated herein by reference.

[0002] [Technical field] The present embodiment relates to, but is not limited to, the field of microelectronics technology, and more particularly, to a soft switching circuit and a control method thereof, and a power supply component including the soft switch. [Background technology]

[0003] A soft switching circuit can reduce switching loss and improve switching frequency, and is widely used in various electronic devices. A soft switching circuit used in an isolated switching power supply is different from a soft switching circuit used in a non-isolated switching power supply. Therefore, in this field, soft switching applicable to both isolated switching power supplies and non-isolated switching power supplies is one of the research directions in this field. Summary of the Invention [Means for solving the problem]

[0004] The present embodiment provides a soft switching circuit, a control method thereof, and a power supply component including the soft switching circuit.

[0005] As a first aspect of the present application, there is provided a soft switching circuit including a switching voltage end, a main inductance, and a second voltage end, the switching voltage end being electrically connected to a first end of the main inductance, and the second voltage end being electrically connected to a second end of the main inductance, the soft switching circuit further including an auxiliary module and a first voltage end, the auxiliary module being connected in series between the switching voltage end and the first voltage end, the auxiliary module being configured to charge the auxiliary module using a first voltage input via the first voltage end when the switching voltage end receives a first level signal, thereby reducing a current flowing through the switching voltage end, and the auxiliary module being further configured to discharge to the switching voltage end when the switching voltage end receives a second level signal, the first level signal and the second level signal being different from each other.

[0006] As a second aspect of the present application, a power supply component is provided, the power supply component including a main circuit and a soft switching circuit. The soft switching circuit is the soft switching circuit according to the first aspect of the present application. The main circuit includes a power supply module, a total output capacitor, and a power supply output terminal, one output terminal of the power supply module and a first pole of the total output capacitor is electrically connected to the switching voltage terminal, the other output terminal of the power supply module and the first pole of the total output capacitor is electrically connected to the second voltage terminal, the anode of the power supply output terminal is electrically connected to the first pole of the total output capacitor, and the cathode of the power supply output terminal is electrically connected to the second pole of the total output capacitor.

[0007] As a third aspect of the present application, there is provided a control method for a soft switching circuit, the soft switching circuit being the soft switching circuit provided by the first aspect of the present application, comprising: when a switching voltage end receives a first level signal, controlling the auxiliary module to charge the auxiliary module with a first voltage input by the first voltage end, thereby reducing a current flowing through the switching voltage end; and when the switching voltage end receives a second level signal, controlling the auxiliary module to discharge to the switching voltage end. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic diagram of a first embodiment of a soft switching circuit provided by the present application; [Diagram 2] FIG. 2 is a schematic diagram of a second embodiment of a soft switching circuit provided by the present application. [Diagram 3] FIG. 1 is a schematic diagram of a first embodiment of a power supply component provided by the present application. [Figure 4] 4 is a schematic diagram showing a timing diagram of each signal in the power supply components shown in FIG. 3, a current flowing through a main inductor, and a current flowing through an auxiliary inductor. [Diagram 5] FIG. 2 is a schematic diagram of a second embodiment of a power supply component provided by the present application. [Figure 6] FIG. 2 is a schematic diagram of a third embodiment of a power supply component provided by the present application. [Figure 7] 7 is a schematic diagram showing a timing diagram of each signal in the power supply components shown in FIGS. 5 and 6, a current flowing through a main inductor, and a current flowing through an auxiliary inductor. FIG. [Figure 8] FIG. 13 is a schematic diagram of a fourth embodiment of a power supply component provided by the present application. [Figure 9] 9 is a timing chart showing signals in the power supply components shown in FIG. 8. [Figure 10] FIG. 9 is a schematic diagram showing a current flowing through a main inductance and a current flowing through an auxiliary inductance in the power supply component shown in FIG. 8. [Figure 11] FIG. 13 is a schematic diagram of a fifth embodiment of a power supply component provided by the present application. [Figure 12] FIG. 13 is a schematic diagram of a sixth embodiment of a power supply component provided by the present application. [Figure 13] FIG. 13 is a schematic diagram of a seventh embodiment of a power supply component provided by the present application. [Figure 14] FIG. 13 is a schematic diagram of an eighth embodiment of a power supply component provided by the present application. [Figure 15] FIG. 13 is a schematic diagram of a ninth embodiment of a power supply component provided by the present application. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] In order to make the technical solution of the present application easier to understand for those skilled in the art, the soft switching circuit and its control method as well as the power supply component including the soft switch provided by the present application are described in detail below in conjunction with the accompanying drawings.

[0010] In the following, exemplary embodiments are described in detail with reference to the drawings, but the exemplary embodiments described may be embodied in different ways and should not be construed as being limited to the embodiments described herein. Rather, the purpose of providing these embodiments is to make the present application thorough and complete so that those skilled in the art can fully appreciate the scope of the present application.

[0011] Unless contradictory, the embodiments and features of the embodiments in this application can be combined with each other in any combination.

[0012] As used herein, the term "and / or" includes any and all combinations of at least one of the associated listed items.

[0013] The terms used in this specification are merely for the purpose of describing particular embodiments and are not intended to limit the present application. In this specification, the singular forms "a" and "the" are intended to include the plural, unless otherwise clear from the context. In addition, when the terms "comprising" and / or "comprising" are used in this specification, they indicate the presence of certain features, wholes, steps, operations, elements, and / or components, but do not exclude the presence or addition of at least one other feature, whole, step, operation, element, component, and / or group thereof.

[0014] Unless otherwise specified, all terms used in this specification (including technical and scientific terms) have the same meaning as those commonly understood by those skilled in the art. Furthermore, terms defined in common dictionaries should be interpreted as having the same meaning as in the relevant art and the context of this application, and should not be interpreted as having an idealized meaning or an excessively formal meaning unless clearly limited in this specification.

[0015] As a first aspect of the present application, a soft switching circuit is provided. As shown in Fig. 1, the soft switching circuit includes a switching voltage end A, a main inductor L, and a second voltage end B, where the switching voltage end A is electrically connected to a first end of the main inductor L, and the second voltage end B is electrically connected to a second end of the main inductor L, where the soft switching circuit further includes an auxiliary module 100 and a first voltage end C, where the auxiliary module 100 is connected in series between the switching voltage end A and the first voltage end C.

[0016] When the switching voltage end A receives a first level signal, the auxiliary module 100 charges the auxiliary module 100 using the first voltage input by the first voltage end C to reduce the current flowing through the switching voltage end A.

[0017] The auxiliary module 100 is further used for discharging the switching voltage end A when the switching voltage end A receives a second level signal. By discharging the switching voltage end A, the current of the switching voltage end A can be increased.

[0018] Here, the first level signal and the second level signal are different from each other, that is, one of the first level signal and the second level signal is a high level signal and the other is a low level signal.

[0019] When the switching voltage A receives a first level signal, the switching voltage end can charge the auxiliary module and reduce the current of the switching voltage end, and when the switching voltage A receives a second level signal, the auxiliary module discharges to the switching voltage end. That is, the adjustment of the switching voltage end A can be realized by changing the level signal supplied to the switching voltage end A, and the function of "soft switching" can be realized.

[0020] In the present application, the auxiliary module 100 has a charging and discharging function. Therefore, by providing the auxiliary module 100, the current flowing through the main inductance L can be adjusted, and the current adjustment of the switching voltage end A can be realized. When the soft switching circuit is used in a switching power supply, whether the power circuit connected to the switching power supply is an isolated circuit or a non-isolated circuit, the switching voltage end current crosses zero, and finally the "soft" switching of the power circuit can be realized. That is, the soft switching circuit provided by the present application can be applied to both isolated and non-isolated switching power supplies.

[0021] In the present application, the specific structure of the auxiliary module 100 is not particularly limited, as long as the switching voltage end A can charge and discharge based on the received level signal, and the main inductance L can help adjust the current of the switching voltage end A.

[0022] As an alternative embodiment, as shown in FIG. 2, the auxiliary module 100 includes an auxiliary inductance La and a control unit 110 connected in series with each other.

[0023] When the switching voltage end A receives the first level signal, the control unit 110 controls both ends of the auxiliary inductance La to be conductive with the first voltage end C and the switching voltage end, respectively, to realize charging of the auxiliary inductance La. By charging the auxiliary inductance La, that is, by "charging the auxiliary module" as mentioned above, the current flowing through the switching voltage end A can be reduced.

[0024] The control unit 110 is further used for controlling the disconnection of the auxiliary inductance La from the first voltage end C and controlling the discharge of the auxiliary inductance La to the switching voltage end when the switching voltage end receives the second level signal.

[0025] The control unit 110 can control the switching of the auxiliary inductance La, the switching voltage end A, and the first voltage end C to control the charging and discharging of the auxiliary inductance La.

[0026] In the present application, there is no particular limitation on the timing of disconnecting the auxiliary inductance La and the first voltage end C. Optionally, the auxiliary module 100 may be further used to discharge the auxiliary inductance La when the switching voltage end A receives a second level signal, and the control unit 110 may be further used to control the disconnection of the auxiliary inductance La and the first voltage end when the discharge of the auxiliary inductance La crosses zero.

[0027] As an alternative embodiment, the auxiliary inductance La can be magnetically coupled to the main inductor L.

[0028] When the switching voltage terminal A receives the first level signal, both ends of the auxiliary inductance La are respectively connected to the first voltage terminal C and the switching voltage terminal A. The first voltage provided by the first voltage terminal C is superimposed on the coupling voltage generated by the main inductance L to charge the auxiliary inductance La, thereby reducing the current flowing through the switching voltage terminal A. When the current flowing through the auxiliary inductance La is greater than the current flowing through the main inductance L, the current at the switching voltage terminal A crosses zero, and "soft" switching is realized.

[0029] When the switching voltage end A receives the second level signal, the auxiliary inductance La is disconnected from the first voltage end C, and in the process of maintaining the second level signal, the switching voltage end A is conductive with the auxiliary inductance La. At this time, the voltage across the main inductance L is reversed, and the auxiliary inductance La is discharged to the switching voltage end due to the effect of superimposing the second level provided by the second voltage end A and the coupling voltage of the main inductance L. The auxiliary inductance La continues to discharge to the second voltage end A until the current in the auxiliary inductance crosses zero, thereby realizing zero current interruption.

[0030] The specific form of the auxiliary inductance La is not particularly limited as long as it is magnetically coupled to the main inductance L and capable of charging and discharging. As an optional embodiment, the auxiliary inductance La is wound around the magnetic core of the main inductance L to realize magnetic coupling.

[0031] In the embodiment shown in FIG. 2, there is a leakage inductance between the auxiliary inductance La and the main inductance.

[0032] In the present application, the specific structure of the control unit 110 is not particularly limited, and it is sufficient if it can control the switching between the auxiliary inductance La and the first voltage terminal C, and the switching between the auxiliary inductance La and the switching voltage terminal A as needed.

[0033] In an alternative embodiment, the control unit 110 comprises a controller and an auxiliary switching element 111 connected in series with an auxiliary inductance La.

[0034] The controller is used for generating a first control signal and outputting the first control signal when the switching voltage end A receives a first level signal, and the controller is further used for generating a second control signal and outputting the second control signal when the switching voltage end A receives a second level signal.

[0035] The control end of the auxiliary switching element 111 is electrically connected to the output end of the controller. The auxiliary switching element 111 is used for turning on when the control end of the auxiliary switching element 111 receives a first control signal, and the auxiliary switching element 111 is further used for turning off when the control end of the auxiliary switching element 111 receives a second control signal.

[0036] By providing an auxiliary switching element 111 and a controller that controls the auxiliary switching element 111, it is possible to control switching between the auxiliary inductance La and the first voltage end C, and switching between the auxiliary inductance La and the switching voltage end A, as needed.

[0037] In order to further simplify the calculation program executed in the controller, optionally, the control unit 110 may further include a unidirectional conductive element 112 connected in series with the auxiliary switching element 111 to unidirectionally discharge the auxiliary inductance La, and the controller generates a second control signal when the current of the auxiliary inductance La is discharged to zero, and controls the auxiliary switching element 111 to be turned off.

[0038] By providing the unidirectional conducting element 112, the controller can determine the timing of generating the second control signal.

[0039] In the present application, there is no particular limitation on how the one-way conductive element 112 and the auxiliary switching element 111 are installed, and as an optional embodiment, the auxiliary switching element 111 and the one-way conductive element 112 are each connected in series to both ends of the auxiliary inductance La.

[0040] In the above embodiment, the unidirectional conducting element 112 is used to allow a current to flow from the auxiliary inductance La to the switching voltage terminal A when the auxiliary switching element 111 is turned off.

[0041] In the present application, the specific structure of the auxiliary switching element 111 is not particularly limited. For example, the auxiliary switching element 111 may be a MOS transistor, and the gate of the MOS transistor is the control end of the auxiliary switching element 111 .

[0042] In the present application, the specific structure of the unidirectional conductive element 112 is not particularly limited. Optionally, the unidirectional conductive element 112 may be a diode. Such a unidirectional conductive element can be turned on and off according to the potential across it, thereby reducing the loss of the soft switching circuit.

[0043] In the present application, there is no particular limitation on the specific locations of the auxiliary switching element 111 and the one-way conducting element 112. Optionally, the auxiliary switching element 111 may be connected in series between the auxiliary inductance La and the first voltage end C, and the one-way conducting element 112 may be connected in series between the auxiliary inductance La and the switching voltage end A.

[0044] In the present application, when the switching voltage terminal A receives the second level signal, there is no particular limitation on when the auxiliary module 100 stops discharging to the switching voltage terminal A. For example, the auxiliary module 100 may discharge to the switching voltage terminal A until the auxiliary module 100 crosses zero.

[0045] As a second aspect of the present application, a power supply component is provided. As shown in Fig. 3, the power supply component includes a main circuit 200 and a soft switching circuit 300, where the soft switching circuit 300 is the soft switching circuit provided by the first aspect of the present application, the main circuit 200 includes a power supply module 210, a total output capacitor Co and a power supply output terminal, one output terminal of the first pole of the power module 210 and the total output capacitor Co is electrically connected to a switching voltage terminal A, the other output terminal of the first pole of the power module 210 and the total output capacitor Co is electrically connected to a second voltage terminal A, the anode of the power supply output terminal is electrically connected to the first pole of the total output capacitor Co, and the cathode of the power supply output terminal is electrically connected to the ground terminal of the total output capacitor Co.

[0046] As mentioned above, the soft switching circuit can be used in an isolated power supply or a non-isolated power supply. Therefore, in the power supply component provided by the present application, the power supply module in the main circuit can be an isolated power supply or a non-isolated power supply.

[0047] In addition, the main circuit may be a step-up circuit or a step-down circuit. According to the specific type of the main circuit, determine which of the power supply module and the first pole of the total output capacitor are electrically connected to the switching voltage end.

[0048] In this application, there is no particular limitation on the specific structure of the power supply module 210. Optionally, the power supply module 210 includes a DC power supply unit 211, and the anode of the DC power supply unit 211 can supply power to the output end of the power supply module 210.

[0049] As an alternative embodiment, as shown in FIG. 3 and FIG. 5, the power supply module includes a DC power supply unit 211, a switching unit S and a free wheel diode D.

[0050] The anode of the DC power supply unit 211 is electrically connected to the first terminal of the switch unit S, and the cathode of the DC power supply unit 211 is electrically connected to the reference voltage terminal.

[0051] The second end of the switching unit S is electrically connected to the switching voltage end A, the anode of the freewheeling diode D is electrically connected to the reference voltage end, and the cathode of the freewheeling diode D is electrically connected to the switching voltage end A.

[0052] A first pole of the total output capacitor Co is electrically connected to a second voltage terminal B, a second pole of the total output capacitor Co is grounded, and the second voltage terminal B is electrically connected to the reference voltage terminal and one of the anodes of the DC power supply component.

[0053] As an alternative embodiment, the power supply module includes a DC power supply unit 211, a switching unit S and a freewheeling diode D, as shown in FIG.

[0054] The anode of the DC power supply unit 211 is electrically connected to the second voltage end B, and the cathode of the DC power supply unit 211 is electrically connected to the reference voltage end.

[0055] One end of the switch unit S is electrically connected to the switching voltage end A, and the other end of the switch unit S is electrically connected to the reference voltage end.

[0056] The anode of the freewheeling diode D is electrically connected to one end of the switching unit S, the cathode of the freewheeling diode D is electrically connected to a first pole of the total output capacitor Co, and the second pole of the total output capacitor Co is electrically connected to the reference voltage terminal; The first voltage terminal C is electrically connected to the reference voltage terminal.

[0057] As an optional embodiment, as shown in FIG. 8, the power supply module includes a DC power supply unit 211, an inverter unit, a transformer unit and a rectifier unit, the two input ends of the inverter unit are electrically connected to the anode and cathode of the DC power supply unit 211 respectively, the input end of the transformer unit is electrically connected to the output end of the inverter unit, the output end of the transformer unit is electrically connected to the input end of the rectifier module, and the output end of the rectifier module is electrically connected to the switching voltage end.

[0058] As an alternative embodiment, the power supply module includes a DC power supply unit 211, a switching unit S and a free wheel diode D, as shown in FIG.

[0059] The anode of the DC power supply unit 211 is electrically connected to the reference voltage terminal, the cathode of the DC power supply unit 211 is electrically connected to one end of the switch unit S, and the other end of the switch unit S is electrically connected to the switching voltage terminal A.

[0060] The anode of the freewheeling diode D is electrically connected to the switching voltage terminal A, and the cathode of the freewheeling diode D is electrically connected to the first pole of the total output capacitor Co.

[0061] The first voltage terminal C is electrically connected to one of the reference voltage terminal and the cathode of the DC power supply unit 211, and the second voltage terminal B is electrically connected to the reference voltage terminal. Specifically, in the embodiment shown in Fig. 11, the first voltage terminal C is electrically connected to the cathode of the DC power supply unit 211, and in the embodiment shown in Fig. 12, the first voltage terminal C is electrically connected to the reference voltage terminal.

[0062] As an optional embodiment, as shown in FIG. 13, the power supply module includes a DC power supply unit 211, a switch capacitor Cs, and a plurality of switching elements connected in series (switching element S1, switching element S2, switching element S3, and switching element S4 in FIG. 13), a first pole of the switching capacitor is electrically connected to an electrical connection node between a first switching element S1 and a second switching element S2 among the plurality of switching elements connected in series, and a second pole of the switching capacitor Cs is electrically connected to an electrical connection node between the last one of the plurality of switching elements connected in series (switching element S4 in FIG. 13) and the penultimate switching element (switching element S3 in FIG. 13) among the plurality of switching elements connected in series.

[0063] The switching voltage terminal A is electrically connected to an electrical connection node between two switching elements (switching element S2 and switching element S3 in FIG. 13) located at the middle position among a plurality of switching elements connected in series, the second voltage terminal B is electrically connected to a first pole of a total output capacitor Co, and the first voltage terminal is electrically connected to a reference voltage terminal.

[0064] The anode of the DC power supply unit 211 is electrically connected to one end of the first of the multiple switching elements connected in series (switching element S1 in FIG. 13), and the cathode of the DC power supply unit 211 is electrically connected to the reference voltage terminal.

[0065] As an optional embodiment, as shown in FIG. 14, the power supply module includes a DC power supply unit 211, a switching capacitor Cs, and a plurality of switching elements connected in series (switching elements S1, S2, S3, and S4 in FIG. 14), a first pole of the switching capacitor Cs is electrically connected to an electrical connection node between a first switching element (switching element S1 in FIG. 14) and a second switching element (switching element S2 in FIG. 14) of the plurality of switching elements connected in series, and a second pole of the switching capacitor Cs is electrically connected to an electrical connection node between the last one (switching element S4 in FIG. 14) and the penultimate switching element (switching element S3 in FIG. 14) of the plurality of switching elements connected in series.

[0066] The switching voltage terminal A is electrically connected to an electrical connection node between two switching elements (switching element S2 and switching element S3 in FIG. 14) located at the middle position among a plurality of switching elements connected in series, the second voltage terminal B is electrically connected to the anode of the DC power supply unit 211, and the first voltage terminal C is electrically connected to the reference voltage terminal.

[0067] The cathode of the DC power supply unit 211 is electrically connected to the reference voltage terminal. As an optional embodiment, as shown in FIG. 15, the power supply module includes a DC power supply unit 211, a switching capacitor Cs, and a plurality of switching elements connected in series (switching elements S1, S2, S3, and S4 in FIG. 15), a first pole of the switching capacitor Cs is electrically connected to an electrical connection node between a first switching element (switching element S1 in FIG. 15) and a second switching element (switching element S2 in FIG. 15) of the plurality of switching elements connected in series, and a second pole of the switching capacitor Cs is electrically connected to an electrical connection node between the last one (switching element S4 in FIG. 15) and the penultimate switching element (switching element S3 in FIG. 15) of the plurality of switching elements connected in series.

[0068] The switching voltage end is electrically connected to an electrical connection node between two switching elements (switching element S2 and switching element S3 in FIG. 15) located in the middle among a plurality of switching elements connected in series, the second voltage end is electrically connected to the anode of the DC power supply component, and the first voltage end is electrically connected to the cathode of the DC power supply component.

[0069] The anode of the DC power supply unit 211 is electrically connected to the reference voltage terminal. The operation processes and principles of the soft switching circuits in different types of main circuits will be described below with reference to FIGS.

[0070] FIG. 3 is a schematic diagram of a first embodiment of a power supply component provided by the present application. Such an embodiment adopts a non-isolated step-down power supply. In the embodiment shown in FIG. 3, the main circuit further includes a freewheeling diode D, and the power supply module 210 includes a DC power supply unit 211 and a switching unit S, the anode of the freewheeling diode D is grounded, and the cathode of the freewheeling diode D is electrically connected to the switching voltage end A. The switching element S, the freewheeling diode D, the main inductance L and the total output capacitor Co constitute a typical Buck-type step-down circuit. By controlling the on / off of the switching unit S, the input voltage Vin provided by the DC power supply unit 211 is converted into a two-level switching voltage of 0 (i.e., the second level signal) and Vin (i.e., the first level signal), and the output voltage Vo is obtained through the low-frequency filter of the main inductance L and the total output capacitor Co, thereby realizing a step-down voltage conversion in which Vo is smaller than Vin.

[0071] 3, the node to which the switching element S and the freewheeling diode D are connected is the switching voltage end A, and the level at the switching voltage end A switches between two levels: Vin (when the switching element S is on) and zero (when the switching element S is off). The first pole of the total output capacitor Co is electrically connected to the second voltage node B of the soft switching circuit, and in this embodiment, the reference voltage of the input / output voltage is the voltage input to the first voltage end C in the soft switching circuit.

[0072] Since the freewheel diode D has a forward conduction voltage drop, in practical applications, a synchronous rectifier can be used instead of the freewheel diode D to reduce losses. That is, the soft switching circuit of the present application can be applied when a diode flywheel and a synchronous rectifier flywheel are used.

[0073] When using the freewheeling diode D for freewheeling, the soft switching circuit provided by the present application can realize zero current cutoff of the diode and reduce reverse recovery loss, and the switching unit S can also realize a turn-on close to zero voltage.

[0074] When synchronous rectifier freewheeling is applied, the soft switching circuit provided in this application can realize zero reverse recovery of the synchronous rectifier body diode, and the switching unit S can also realize zero voltage turn-on.

[0075] Any of the freewheeling diodes referred to in this application may be implemented with a synchronous rectifier. In controlling the soft switching circuit and implementing the waveform, a synchronous rectifier is described as a switching unit S. The switch unit S described in this application is not limited to being implemented by a metal oxide field effect transistor (MOSFET), and preferably, the switch unit S is a MOSFET, and hereinafter, the MOSFET is described as a switch unit S. It should be noted that in a MOSFET device, a parasitic body diode and a parasitic output capacitor exist, and due to the existence of the parasitic body diode, the MOSFET device can replace one of the characteristics of a freewheeling diode as a synchronous rectifier, and the parasitic output capacitor causes switching loss when the switching unit S is switched, and the parasitic output capacitor is discharged, and then the switching unit S is turned on, thereby realizing one of the important means and purposes of the soft switching circuit, and reducing the switching loss.

[0076] Fig. 4 is a waveform diagram of signals that control the soft switching circuit in Fig. 3. In Fig. 4, Gs is a control signal waveform for the switch unit S, and when it is at a high level, the switch unit S is turned on, and when it is at a low level, the switch unit S is turned off. Gd is a control signal waveform when the freewheel diode D shown in Fig. 3 employs a synchronous rectifier, and Ga is a control signal waveform for the auxiliary switching element 111. Vd is the voltage across the switching unit S, iL is the current waveform of the main inductance L, and iLa is the current waveform of the auxiliary inductance La.

[0077] Before the auxiliary switching element 111 is turned on, the freewheeling diode D is turned on, the level of the switching voltage terminal is 0 (equal to the reference voltage), and the voltage V across the main inductance L L is -Vo, and since the main inductance L is large, the change in the current flowing through the main inductance L at the time of switching is not large.

[0078] When the auxiliary switching element 111 is on, the voltage V across the auxiliary inductance La is calculated using the following formula: La Calculate.

[0079]

number

[0080] Here, V L is the voltage across the main inductor, N is the ratio of the number of turns that the auxiliary inductance and the main inductance combine together.

[0081] When the auxiliary switching element 111 is turned on, the auxiliary inductance La starts to charge, and the current flowing through the freewheeling diode D starts to decrease as the current iLa flowing through the auxiliary inductance La is subtracted from the current iL flowing through the main inductor L. Since the inductance of the auxiliary inductance La is small, the charging speed is fast, and when iLa is larger than iL, the current flowing through the freewheeling diode D becomes zero, and the reverse recovery loss of the freewheeling diode D can be significantly reduced.

[0082] When the auxiliary switching element 1111 is realized by a synchronous rectifier, the synchronous rectifier starts to flow a reverse current. Then, the control signal Gd of the synchronous rectifier is turned off, the parasitic output capacitor of the auxiliary switching element 111 is discharged by the reverse current, and after discharging to zero, the parasitic body diode of the switching unit S performs a reflux, at this time, the voltage Vd between both ends of the switching unit S is 0, and Gs is controlled to a high level to realize the zero voltage conduction of the switching unit S.

[0083] After the switch unit S is turned on, the switch voltage level is Vin, and the voltage across the main inductor L is V L At this time, the voltage V across the auxiliary inductance La is La is as follows:

[0084]

number

[0085] The step-down circuit is V in V o Because it is larger, when the auxiliary inductance La starts to discharge and the current flowing through the auxiliary inductance La drops to zero, the one-way conducting element 112 is cut off, the current of the auxiliary inductance La becomes intermittent, and the auxiliary switching element 111 can achieve zero current cut-off, that is, the auxiliary switching element 111 has no cutting loss.

[0086] As can be seen from the waveform shown in Figure 4, according to the soft switching circuit described in the present invention, the current of the main power inductor L is maintained continuously, and the ripple is small, so that it does not affect the effective value and peak value of the current, and therefore does not affect the conduction loss and interruption loss of the switching circuit. At the same time, the auxiliary inductance current of the soft switching circuit only works when the switching timing is relatively short, so that the extra conduction loss of the soft switching circuit is small, and the auxiliary inductance current can be automatically discharged to zero, realizing zero current interruption and no extra interruption loss.

[0087] 5 is a circuit diagram of a second embodiment of the power supply component provided by the present application. The difference between the power supply component shown in FIG. 5 and the power supply component shown in FIG. 3 is that the first voltage end C of the soft switching circuit 300 is electrically connected to the anode of the DC power supply unit 211.

[0088] In the power supply component shown in FIG. 5, when the level of the switching voltage terminal A is 0 (equal to the reference voltage), the auxiliary switching element 111 is turned on, and the resulting charging voltage of the auxiliary inductance La is:

[0089]

number

[0090] The level of the switching voltage terminal A is V in Then, the discharge voltage of the auxiliary inductance La is as follows:

[0091]

number

[0092] The power supply component disclosed in FIG. 5 is often used in general step-down applications in which the duty ratio is small and the input / output voltage is relatively large, and the charge / discharge voltage of the auxiliary inductance La is relatively balanced, thereby enabling a better soft switching effect to be achieved.

[0093] FIG. 6 is a circuit diagram of a third embodiment of a power supply component provided by the present application. The power supply component in FIG. 6 is a non-isolated boost type power supply component. In FIG. 6, a switching unit S, a freewheeling diode D, a main inductance L and a total output capacitor Co constitute a typical Boost type step-down circuit. The output voltage V o is the input voltage V in This realizes a boost voltage conversion that is greater than

[0094] In this embodiment, the node at which the switching unit S and the anode of the freewheeling diode D are electrically connected is electrically connected to the switching voltage end A of the soft switching circuit 300, and the voltage of the switching voltage end A is between zero (when the switching unit S is on) and V o (when the switching unit S is off). The anode of the DC power supply unit 211 is electrically connected to the second voltage end B of the soft switching circuit 300, and the first voltage end C is electrically connected to the reference voltage end.

[0095] Fig. 7 is a timing diagram and a current schematic diagram of the control signal of the switching unit circuit in the power supply component shown in Fig. 6. In Fig. 7, Gs is the control signal waveform of the switch unit S, and when the control signal is at a high level, the switch unit S turns on, and when the control signal is at a low level, the switch unit S turns off. Gd is the control signal waveform when the freewheel diode D is a synchronous rectifier, and Ga is the control signal waveform of the auxiliary switching element 111. Vd is the voltage across the switching unit S, iL is the current waveform of the main inductance L, and iLa is the current waveform of the auxiliary inductance La.

[0096] Before the auxiliary switching element 111 is turned on, the freewheeling diode D is turned on, and the level of the switching voltage end becomes equal to the output voltage V o and the voltage across the main inductor L is V L V in -V o Since the inductance of the main inductor L is large, the change in the current flowing through the main inductor L at the time of switching is not large.

[0097] When the auxiliary switching element 111 is on, the voltage VLa across the auxiliary inductance La is calculated by the following formula.

[0098]

number

[0099] When the auxiliary inductance La starts to charge, and the current iLa flowing through the auxiliary inductance La is greater than the current iL flowing through the main inductance L, the current flowing through the freewheeling diode D becomes zero, and the reverse recovery loss of the freewheeling diode D can be greatly reduced. When the freewheeling diode D is realized by a synchronous rectifier, a reverse current begins to flow through the synchronous rectifier as the freewheeling diode D. Then, the control signal Gd of the synchronous rectifier used for the freewheeling diode D is turned off, and the reverse current discharges the parasitic output capacitor of the switch unit S, and after discharging to zero, it is circulated by the parasitic body diode of the switch unit S. At this time, the voltage Vd across the switch unit S is 0, and the zero-voltage turn-on of the switch unit S can be realized by controlling Gs to a high level.

[0100] After the switch unit S is turned on, the switching voltage end A is grounded, the level of the switching voltage end A is 0, and the voltage across the main inductor L is V L is the voltage V output by the DC power supply component in At this time, the voltage V across the auxiliary inductance La La is calculated according to the following formula:

[0101]

number

[0102] Thereafter, when the auxiliary inductance La starts to discharge and the current flowing through the auxiliary inductance La drops to zero, the one-way conducting element 112 is cut off, the current flowing through the auxiliary inductance La becomes intermittent, and the auxiliary switching element 111 achieves zero current cutoff and has no cutoff loss.

[0103] Fig. 8 is a schematic diagram of the third embodiment of the power supply component provided by the present application. This embodiment is an isolated power supply component. In the embodiment shown in Fig. 8, the main power part is a typical full-bridge isolated circuit, and the inverter circuit composed of main switches S1-S4 converts the DC voltage input from the DC power supply unit 211 into a high-frequency AC switching voltage, which is isolated by the transformer T1 and then rectified by the bridge rectifier circuit composed of rectifier diodes D1-D4 to obtain the switching voltage of the secondary side, which is low-pass filtered by the main inductance L and the main output capacitor Co to obtain the isolated output voltage.

[0104] In the embodiment shown in FIG. 8, the output terminal of the secondary side rectifier circuit is electrically connected to the switching voltage terminal A of the soft switching circuit 300, and the voltage output from the output terminal of the secondary side rectifier circuit is zero (refer to the output voltage) and V in / N T1 where N T1 is the ratio of the number of turns of the main side and the sub-side of the isolation transformer T1. The first pole of the main storage capacitor C0 is the output end of the power supply component, the first pole of the main storage capacitor C0 is electrically connected to the second voltage end B of the soft switching circuit 300, and the second voltage end C of the soft switching circuit 300 is electrically connected to a reference voltage (in this embodiment, the reference voltage is the ground voltage).

[0105] FIG. 9 is a specific waveform of the control signal of the soft switching circuit of the embodiment shown in FIG. 8 of the present invention. In FIG. 9, G1 is the control signal waveform of the main side main switches S1 and S4, and G2 is the control signal waveform of the main side main switches S2 and S3. Gd1 is the control signal waveform when the sub-side rectifier diodes D1 and D4 adopt synchronous rectifiers, and Gd2 is the control signal waveform when the sub-side rectifier diodes D2 and D3 adopt synchronous rectifiers. Ga is the control signal waveform of the auxiliary switch tube. Vsw is the switching voltage node waveform in the embodiment shown in FIG. 8.

[0106] Specifically, Fig. 10 shows waveforms realized in the specific soft switching circuit of the embodiment shown in Fig. 8 of the present invention. Vds is the voltage across the main switch S4, iL is the current waveform of the main inductor L, and iLa is the auxiliary inductance current waveform.

[0107] Before the auxiliary switching element 111 is turned on, the secondary rectifier diodes D1 to D4 are turned on, the switching voltage level is the secondary reference voltage 0, and the voltage V across the main inductance L L is (0-Vo), and since the inductance of the main inductance L is large, the change in the current flowing through the main inductance L at the switching timing is not large.

[0108] When the auxiliary switching element 111 is turned on, the voltage VLa across the auxiliary inductance La is calculated by the following formula.

[0109]

number

[0110] When the auxiliary inductance La starts to charge, and the current iLa flowing through the auxiliary inductance La is greater than the current iL flowing through the main inductance L, the current flowing through the rectifier diodes D1 to D4 becomes zero, and the reverse recovery loss of the rectifier diodes can be greatly reduced. If the rectifier diodes are realized by synchronous rectifiers, the synchronous rectifiers start to flow a reverse current. Then, the control signal Gd2 of the synchronous rectifiers D2 and D3 is turned off, and the reverse current is mapped to the main side winding through the isolation transformer T1 by D1 and D4, discharging the parasitic output capacitor of the main side switching transistor S, and after discharging to zero, it is circulated by the parasitic body diodes of the main switching transistors S1 and S4. At this time, the voltage Vds at both ends of the main switching transistors S1 and S4 is 0, and Gs is controlled to a high level, and the zero-voltage turn-on of the main switching transistors S1 and S4 can be realized. In the same process, the zero-voltage turn-on of the main switches S2 and S3 can be realized in the next period.

[0111] After S1 and S4 are turned on, the main winding of the transformer is connected to the anode of the DC power supply unit 211, and the voltage is the output voltage V in The level of the switching voltage terminal A shown in Figure 8, which is the output of the secondary side rectifier circuit, is V in / N T1 and the voltage V across the main inductance L L is V in / N T1 -V o The voltage across the auxiliary inductance V is calculated using the following formula: La Get the.

[0112]

number

[0113] Then, when the auxiliary inductance La starts to discharge and the current flowing through the auxiliary inductance La drops to zero, the one-way conducting element 112 is cut off, the current flowing through the auxiliary inductance La becomes intermittent, and the auxiliary switching element 111 can achieve zero current cut-off, that is, the auxiliary switching element 111 has no cutting loss.

[0114] 11 and 12 are schematic diagrams of a fourth embodiment of the power supply component provided by the present application. The power supply component shown in Fig. 11 and Fig. 12 is a non-isolated reverse step-up / step-down circuit, in which the output voltage is reversed to the input voltage by the reverse charging and discharging of the main inductance L.

[0115] 11 and 12, the connection node between the main switching unit S and the anode of the diode D is connected to the input voltage V in (When the main switching unit S is on) and the output voltage V o (when the main switching unit S is off) and the switching voltage end A of the soft switching circuit 300 is electrically connected to the switching voltage end A so that the voltage at the switching voltage end A switches between two levels. in and the output voltage V o The reference voltage V is the voltage at the first voltage end of the soft switching circuit 300. In FIG. in is the voltage at the first voltage end A of the soft switching circuit 300. In FIG. o The voltage is the voltage at the first voltage end A of the soft switching circuit 300.

[0116] 13 is a schematic diagram of a fifth embodiment of a power supply component provided by the present application. The power supply component in FIG. 13 is a switching capacitor multilevel step-down circuit, in which the input voltage V inWhen the main switching transistors S2 and S4 are on, the switching capacitor Cs supplies power to the output inductor. The voltage of the switching capacitor Cs is half the input voltage, so a multi-level scheme of switched capacitors is adopted, and the Vds voltage of the main switching transistors S1 to S4 is V in 13, the connection node of the main switches S2 and S3 is electrically connected to the switching voltage end A of the soft switching circuit 300, and the level of the switching voltage end A is the input voltage V in (When S1 and S2 are on), 1 / 2V in It can be switched between three levels: (when S1, S3 or S2, S4 are on) and zero (when S3, S4 are on). The output voltage is the second voltage end B of the soft switching circuit 300. The input and output voltages are referenced to the first voltage end A of the voltage soft switching circuit.

[0117] 14 is a schematic diagram of a sixth embodiment of a power supply component provided by the present application. The power supply component shown in FIG. 14 is a multi-level boost circuit, similar to the embodiment shown in FIG. 13, in which the voltage of the switching capacitor Cs is half the output voltage Vo, and the Vds voltage of the main switching transistors S1-S4 of the boost circuit is V o 14, the connection node of the main switches S2 and S3 is the switching voltage end A of the soft switching circuit 300, and the voltage at the switching voltage end A is the output voltage V o (When S1 and S2 are on), 1 / 2V o It can be switched between three levels: zero (when S1, S3 or S2, S4 are on) and zero (when S3, S4 are on). The voltage at the second voltage end B of the voltage soft switching circuit 300 is input. The input / output voltage reference voltage is the voltage at the first voltage end C of the soft switching circuit 300.

[0118] FIG. 15 is a schematic diagram of a seventh embodiment of a power supply component provided by the present application. The power supply component is an application example in an inverse multilevel buck-boost circuit. In FIG. 15, the input voltage V in is a negative voltage, for example, −48V that is often used in communication systems, and the operation method is similar to the embodiment shown in FIG. 11 and FIG. 12, and the reverse direction of the output voltage is realized by reverse charging and discharging of the main inductance L. Similar to the embodiment shown in FIG. 13 and FIG. 14, the voltage of the switching capacitor Cs is half the input / output voltage difference, and the Vds voltage of the main switching transistors S1 to S4 is reduced to (Vo-Vin) / 2 by the switching capacitor Cs. In the embodiment shown in FIG. 15, the connection node of the main switches S2 and S3 is connected to the switching voltage end A of the soft switching circuit 300, and the voltage of the switching voltage end A is the output voltage Vo (when S1 and S2 are on), 1 / 2 (V o +V in ) (when S1, S3 or S2, S4 are on) and input voltage Vin (when S3, S4 are on). The input / output voltage reference voltage is the voltage at the second voltage end B of the soft switching circuit 300. The input / output voltage is the voltage at the first voltage end A of the soft switching circuit 300.

[0119] According to a third aspect of the present application, there is provided a control method for a soft switching circuit, the soft switching circuit being the soft switching circuit provided in the first aspect of the present application, the control method comprising: When the switching voltage end receives a first level signal, control the auxiliary module to charge the auxiliary module with a first voltage input by the first voltage end, thereby reducing the current flowing through the switching voltage end; and controlling the auxiliary module to discharge to the switching voltage end when the switching voltage end receives a second level signal.

[0120] The control method is for controlling the soft switching circuit of the power supply component provided in the second embodiment, and its working principle has been described in detail above, so it will not be described again here.

[0121] Those skilled in the art will understand that all or part of the steps in the methods, the functional modules / units in the systems, the devices disclosed above may be implemented as software, firmware, hardware, and appropriate combinations thereof. In hardware embodiments, the division between the functional modules / units mentioned in the above description does not necessarily correspond to the division of physical components. For example, one physical component may have multiple functions, or one function or step may be performed by several physical components in cooperation. Some or all of the physical components may be implemented as software executed by a processing unit (e.g., a central processing unit, a digital signal processor, or a microprocessor), as hardware, or as an integrated circuit such as a dedicated integrated circuit. Such software may be located on a computer-readable medium, which may include computer storage media (or non-transitory media) and communication media (or transitory media). As is well known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information such as computer-readable commands, data structures, program modules, or other data. Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and that can be accessed by a computer. Additionally, those skilled in the art will appreciate that communication media typically include computer readable commands, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

[0122] Although exemplary embodiments are disclosed and specific terms are used herein, they are merely used for general description and should be interpreted as such, and are not intended to be limiting. It will be apparent to those skilled in the art that, unless expressly indicated otherwise, in some embodiments, the features, characteristics and / or elements described in connection with a particular embodiment may be used alone or in combination with the features, characteristics and / or elements described in connection with other embodiments. Thus, those skilled in the art will appreciate that changes in various forms and details may be made without departing from the scope of the present application as defined by the appended claims.

Claims

1. The soft switching circuit includes a switching voltage end, a main inductance, and a second voltage end, the switching voltage end is electrically connected to a first end of the main inductance, and the second voltage end is electrically connected to a second end of the main inductance; the soft switching circuit further includes an auxiliary module and a first voltage end, the auxiliary module is connected in series between the switching voltage end and the first voltage end; The auxiliary module is configured to charge the auxiliary module using a first voltage input by the first voltage end when the switching voltage end receives a first level signal, thereby reducing the current flowing through the switching voltage end; The auxiliary module is further configured to discharge the switching voltage end when the switching voltage end receives a second level signal, and the first level signal and the second level signal are different from each other. Soft switching circuit.

2. The auxiliary module includes an auxiliary inductance and a control unit connected in series with each other; The control unit is configured to control both ends of the auxiliary inductance to be conductive to the first voltage end and the switching voltage end, respectively, when the switching voltage end receives the first level signal, to charge the auxiliary inductance; The control unit is further configured to control a disconnection between the auxiliary inductance and the first voltage end when discharging the auxiliary inductance in a state where the switching voltage end receives the second level signal.

2. The soft switching circuit of claim 1.

3. The auxiliary inductance can be magnetically coupled to the main inductance.

3. The soft switching circuit of claim 2.

4. The auxiliary inductor is wound around the core of the main inductor.

4. The soft switching circuit of claim 3.

5. The control unit includes a controller and an auxiliary switching element, the auxiliary switching element being connected in series with the auxiliary inductance; The controller is configured to generate and output a first control signal when the switching voltage end receives a first level signal, and the controller is configured to generate and output a second control signal when the switching voltage end receives a second level signal; a control end of the auxiliary switching element is electrically connected to an output end of the controller, and the auxiliary switching element is configured to be turned on when the control end of the auxiliary switching element receives the first control signal, and to be turned off when the control end of the auxiliary switching element receives the second control signal; A soft switching circuit according to any one of claims 2 to 4.

6. the control unit further includes a unidirectional conductive element connected in series with the auxiliary switching element, the unidirectional conductive element discharging the auxiliary inductance in one direction, and the controller is configured to generate a second control signal when the auxiliary inductance current is discharged to zero to control the auxiliary switching element to be turned off. A soft switching circuit according to any one of claims 2 to 4.

7. The unidirectional conducting element is a diode.

7. The soft switching circuit of claim 6.

8. The auxiliary module is further configured to discharge the auxiliary inductance when the switching voltage end receives a second level signal, and the control unit controls the disconnection of the auxiliary inductance and the first voltage end when the auxiliary inductance crosses zero discharge. A soft switching circuit according to any one of claims 2 to 4.

9. A power supply component including a body circuit and a soft switching circuit, The soft switching circuit is a soft switching circuit according to any one of claims 1 to 8, The main circuit includes a power supply module, a total output capacitor, and a power supply output terminal, the power supply module and one output terminal of a first pole of the total output capacitor are electrically connected to the switching voltage terminal, the power supply module and the other output terminal of the first pole of the total output capacitor are electrically connected to the second voltage terminal, the anode of the power supply output terminal is electrically connected to the first pole of the total output capacitor, and the cathode of the power supply output terminal is electrically connected to the second pole of the total output capacitor; Power components.

10. The power supply module includes a DC power supply unit, a switching unit and a freewheeling diode; The anode of the DC power supply unit is electrically connected to the first end of the switch unit, and the cathode of the DC power supply unit is electrically connected to a reference voltage end; A second end of the switching unit is electrically connected to the switching voltage end, an anode of the freewheeling diode is electrically connected to the reference voltage end, and a cathode of the freewheeling diode is electrically connected to the switching voltage end; A first pole of the total output capacitor is electrically connected to the second voltage terminal, and the second voltage terminal is electrically connected to the reference voltage terminal and electrically connected to one of the anodes of the DC power supply unit; 10. The power supply component of claim 9.

11. The power supply module includes a DC power supply unit, a switching unit and a freewheeling diode; The anode of the DC power supply unit is electrically connected to the second voltage end, and the cathode of the DC power supply unit is electrically connected to a reference voltage end; One end of the switch unit is electrically connected to the switching voltage end, and the other end of the switch unit is electrically connected to a reference voltage end; an anode of the freewheeling diode is electrically connected to one end of the switching unit, and a cathode of the freewheeling diode is electrically connected to a first pole of the total output capacitor; The first voltage terminal is electrically connected to the reference voltage terminal.

10. The power supply component of claim 9.

12. The power supply module includes a DC power supply unit, an inverter unit, a transformer unit, and a rectifier unit, the two input ends of the inverter unit are respectively electrically connected to the anode and the cathode of the DC power supply unit, the input end of the transformer unit is electrically connected to the output end of the inverter unit, the output end of the transformer unit is electrically connected to the input end of the rectifier module, and the output end of the rectifier module is electrically connected to the switching voltage end; 10. The power supply component of claim 9.

13. The power supply module includes a DC power supply unit, a switching unit, and a freewheeling diode; An anode of the DC power supply unit is electrically connected to a reference voltage end, a cathode of the DC power supply unit is electrically connected to one end of the switch unit, and the other end of the switch unit is electrically connected to the switching voltage end; an anode of the freewheeling diode is electrically connected to the switching voltage terminal, and a cathode of the freewheeling diode is electrically connected to a first pole of the sum output capacitor; The first voltage terminal is electrically connected to one of the reference voltage terminal and the cathode of the DC power supply unit, and the second voltage terminal is electrically connected to the reference voltage terminal.

10. The power supply component of claim 9.

14. The power supply module includes a DC power supply unit, a switching capacitor, and a plurality of switching elements connected in series, a first pole of the switching capacitor being electrically connected to an electrical connection node between a first switching element and a second switching element of the plurality of switching elements connected in series, and a second pole of the switching capacitor being electrically connected to an electrical connection node between a last switching element and a penultimate switching element of the plurality of switching elements connected in series. the switching voltage terminal is electrically connected to an electrical connection node between two switching elements located at a middle position among a plurality of switching elements connected in series, the second voltage terminal is electrically connected to a first pole of the total output capacitor, and the first voltage terminal is electrically connected to a reference voltage terminal; The anode of the DC power supply unit is electrically connected to one end of a first one of a plurality of switching elements connected in series, and the cathode of the DC power supply unit is electrically connected to the reference voltage terminal.

10. The power supply component of claim 9.

15. The power supply module includes a DC power supply unit, a switching capacitor, and a plurality of switching elements connected in series, a first pole of the switching capacitor being electrically connected to an electrical connection node between a first switching element and a second switching element among the plurality of switching elements connected in series, and a second pole of the switching capacitor being electrically connected to an electrical connection node between a last switching element and a penultimate switching element among the plurality of switching elements connected in series, the switching voltage end is electrically connected to an electrical connection node between two switching elements located at a middle position among a plurality of switching elements connected in series, the second voltage end is electrically connected to an anode of the DC power supply unit, and the first voltage end is electrically connected to a reference voltage end; The cathode of the DC power supply component is electrically connected to the reference voltage terminal; 10. The power supply component of claim 9.

16. The power supply module includes a DC power supply unit, a switching capacitor, and a plurality of switching elements connected in series, a first pole of the switching capacitor being electrically connected to an electrical connection node between a first switching element and a second switching element among the plurality of switching elements connected in series, and a second pole of the switching capacitor being electrically connected to an electrical connection node between a last switching element and a penultimate switching element among the plurality of switching elements connected in series, The switching voltage end is electrically connected to an electrical connection node between two switching elements located at a middle position among a plurality of switching elements connected in series, the second voltage end is electrically connected to an anode of the DC power supply unit, and the first voltage end is electrically connected to a cathode of the DC power supply unit; The anode of the DC power supply unit is electrically connected to a reference voltage terminal; 10. The power supply component of claim 9.

17. 1. A method for controlling a soft switching circuit, comprising: The soft switching circuit is a soft switching circuit according to any one of claims 1 to 8, When a switching voltage end receives a first level signal, control the auxiliary module to charge the auxiliary module with a first voltage input by the first voltage end, thereby reducing the current flowing through the switching voltage end; When the switching voltage end receives a second level signal, the auxiliary module is controlled to discharge the switching voltage end. A method for controlling a soft switching circuit.

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