Soft switching circuit, its control method 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 embodiments relate to, but are 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] Soft switching circuits can reduce switching losses and improve switching frequencies, and are widely used in various electronic devices. The soft switching circuits used in isolated switching power supplies are different from the soft switching circuits used in non-isolated switching power supplies. Therefore, in this field, soft switching that can be applied to both isolated 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] In a first aspect of the present application, there is provided a soft switching circuit including a switching voltage terminal, a main inductance, and a second voltage terminal, the switching voltage terminal being electrically connected to a first terminal of the main inductance and the second voltage terminal being electrically connected to a second terminal of the main inductance, the soft switching circuit further including an auxiliary module and a first voltage terminal, the auxiliary module being connected in series between the switching voltage terminal and the first voltage terminal, the auxiliary module being configured to charge the auxiliary module using a first voltage input via the first voltage terminal when the switching voltage terminal receives a first level signal, thereby reducing a current flowing through the switching voltage terminal, and the auxiliary module being further configured to discharge to the switching voltage terminal when the switching voltage terminal receives a second level signal, the first level signal and the second level signal being different from each other.

[0006] According to a second aspect of the present application, there is provided a power supply component, 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, wherein one output terminal of the power supply module and a first pole of the total output capacitor are 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 are electrically connected to the second voltage terminal, an anode of the power supply output terminal is electrically connected to the first pole of the total output capacitor, and a cathode of the power supply output terminal is electrically connected to the second pole of the total output capacitor.

[0007] A third aspect of the present application provides 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 the switching voltage end. [Brief explanation 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; [Figure 2] FIG. 2 is a schematic diagram of a second embodiment of a soft switching circuit provided by the present application. [Figure 3] 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 the timing of each signal in the power supply components shown in FIG. 3, the current flowing through the main inductor, and the current flowing through the auxiliary inductor. FIG. [Figure 5] FIG. 2 is a schematic diagram of a second embodiment of a power supply component provided by the present application. [Figure 6] FIG. 10 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 timing diagrams of signals in the power supply components shown in FIGS. 5 and 6, currents flowing through the main inductor, and currents flowing through the auxiliary inductance. FIG. [Figure 8] FIG. 10 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 the current flowing through the main inductance and the current flowing through the auxiliary inductance in the power supply components shown in FIG. 8. [Figure 11] FIG. 10 is a schematic diagram of a fifth embodiment of a power supply component provided by the present application. [Figure 12] FIG. 10 is a schematic diagram of a sixth embodiment of a power supply component provided by the present application. [Figure 13] FIG. 10 is a schematic diagram of a seventh embodiment of a power supply component provided by the present application. [Figure 14] FIG. 10 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 INVENTION

[0009] In order to help those skilled in the art better understand the technical solution of the present application, the soft switching circuit and control method thereof and the power supply components including the soft switch provided by the present application will be described in detail below in conjunction with the accompanying drawings.

[0010]

[0023] The following detailed description of exemplary embodiments is provided with reference to the drawings, but the described exemplary embodiments may be embodied in different forms and should not be construed as being limited to the embodiments set forth herein. Rather, the purpose of providing these examples is to provide a thorough and complete disclosure of the present application 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 the present application may 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 herein are for the purpose of describing particular embodiments only and are not intended to limit the present application. In this specification, the singular forms "a," "an," and "the" are intended to include the plural, unless the context clearly dictates otherwise. Furthermore, when used herein, the terms "comprising" and / or "consisting of" 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 (including technical and scientific terms) used in this specification have the same meaning as commonly understood by those skilled in the art. Furthermore, terms defined in commonly used 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, there is provided a soft switching circuit. As shown in Figure 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, and 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 the first level signal, the auxiliary module 100 uses the first voltage input by the first voltage end C to charge the auxiliary module 100 and reduce the current flowing through the switching voltage end A.

[0017] The auxiliary module 100 is further used to discharge the switching voltage end A when the switching voltage end A receives the second level signal, and 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; when the switching voltage A receives a second level signal, the auxiliary module discharges to the switching voltage end. That is, by changing the level signal supplied to the switching voltage end A, the switching voltage end A can be adjusted, thereby realizing the function of "soft switching".

[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, thereby realizing current adjustment at the switching voltage end A. 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 current at the switching voltage end can cross zero, ultimately realizing "soft" switching of the power circuit. In other words, the soft switching circuit provided in 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] In 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 the auxiliary inductance La so that both ends thereof are respectively connected to the first voltage end C and the switching voltage end, thereby realizing charging of the auxiliary inductance La. By charging the auxiliary inductance La, i.e., 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 between the auxiliary inductance La and the first voltage end C, and controlling the discharge of the auxiliary inductance La to the switching voltage end A, when the switching voltage end receives the second level signal and the auxiliary inductance La is to be discharged.

[0025] The control unit 110 controls the switching of the auxiliary inductance La, the switching voltage terminal A, and the first voltage terminal 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 at which the auxiliary inductance La is disconnected from 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 the second level signal, and the control unit 110 may be further used to control the disconnection of the auxiliary inductance La from the first voltage end when the discharge of the auxiliary inductance La crosses zero.

[0027] In 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 electrically connected to the first voltage terminal C and the switching voltage terminal A, respectively. The first voltage provided by the first voltage terminal C is superimposed on the coupling voltage generated by the main inductance L, thereby charging 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, realizing "soft" switching.

[0029] When the switching voltage terminal A receives the second level signal, the auxiliary inductance La disconnects from the first voltage terminal C, and while maintaining the second level signal, the switching voltage terminal A conducts with the auxiliary inductance La. At this time, the voltage across the main inductance L is reversed, and the second level provided by the second voltage terminal A is superimposed on the coupling voltage of the main inductance L, causing the auxiliary inductance La to discharge to the switching voltage terminal. The auxiliary inductance La continues to discharge to the second voltage terminal A until the current in the auxiliary inductance crosses zero, thereby achieving 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 is capable of charging and discharging. In an optional embodiment, the auxiliary inductance La is wound around the magnetic core of the main inductance L to achieve 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 to generate a first control signal and output the first control signal when the switching voltage end A receives a first level signal, and the controller is further used to generate a second control signal and output 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, and the auxiliary switching element 111 is turned on when the control end of the auxiliary switching element 111 receives a first control signal, and the auxiliary switching element 111 is turned 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 the switching between the auxiliary inductance La and the first voltage end C, and the switching between the auxiliary inductance La and the switching voltage end A, as needed.

[0037] To further simplify the calculation program executed in the controller, optionally, the control unit 110 may further include a unidirectional conducting 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 one-way conducting element 112, the controller can determine the timing for generating the second control signal.

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

[0040] In the above embodiment, the one-way conducting element 112 is used to allow 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 one-way conducting element 112 is not particularly limited. Optionally, the one-way conducting element 112 may be a diode. Such a one-way conducting 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, it is not particularly limited when the auxiliary module 100 stops discharging to the switching voltage terminal A. For example, the auxiliary module 100 may continue discharging to the switching voltage terminal A until the auxiliary module 100 crosses zero.

[0045] A second aspect of the present invention provides a power supply component. As shown in Figure 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 invention. The main circuit 200 includes a power supply module 210, a total output capacitor Co, and a power supply output terminal, where one output terminal of a first pole of the power module 210 and the total output capacitor Co is electrically connected to a switching voltage terminal A, and 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, so 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. Depending on the specific type of the main circuit, the power supply module and the first pole of the total output capacitor are electrically connected to the switching voltage end.

[0048] This application does not particularly limit 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] In 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 FIGS.

[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 free wheel 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 the 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, wherein the two input terminals of the inverter unit are electrically connected to the anode and cathode of the DC power supply unit 211, respectively, the input terminal of the transformer unit is electrically connected to the output terminal of the inverter unit, the output terminal of the transformer unit is electrically connected to the input terminal of the rectifier module, and the output terminal of the rectifier module is electrically connected to the switching voltage terminal.

[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 FIGS.

[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 (represented by switching element S1, switching element S2, switching element S3, and switching element S4 in FIG. 13), a first pole of the switching capacitor being electrically connected to an electrical connection node between the first switching element S1 and the second switching element S2 of the plurality of switching elements connected in series, and a second pole of the switching capacitor Cs being 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 second-to-last switching element (switching element S3 in FIG. 13) of 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) 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 the 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 Figure 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, respectively, in FIG. 14), a first pole of the switching capacitor Cs is electrically connected to an electrical connection node between the first switching element (switching element S1 in FIG. 14) and the 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 second-to-last 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) 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, respectively, in FIG. 15), a first pole of the switching capacitor Cs is electrically connected to an electrical connection node between the first switching element (switching element S1 in FIG. 15) and the 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 second-to-last switching element (switching element S3 in FIG. 15) of the plurality of switching elements connected in series.

[0068] The switching voltage terminal is electrically connected to an electrical connection node between two switching elements (switching element S2 and switching element S3 in FIG. 15) at an intermediate position among a plurality of switching elements connected in series, the second voltage terminal is electrically connected to an anode of the DC power supply component, and the first voltage terminal is electrically connected to a 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 process 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. This embodiment employs a non-isolated buck 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 terminal A. The switching element S, the freewheeling diode D, the main inductance L, and the total output capacitor Co constitute a typical Buck-type buck 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, 0 (i.e., a second-level signal) and Vin (i.e., a first-level signal), which is then passed through a low-frequency filter including the main inductance L and the total output capacitor Co to obtain an output voltage Vo, thereby achieving a buck voltage conversion where 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 terminal A, and the level at the switching voltage terminal 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 terminal C in the soft switching circuit.

[0072] Since the freewheel diode D has a forward conduction voltage drop, in actual 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 achieve zero current cutoff of the diode, reduce reverse recovery loss, and also enable the switching unit S to turn on at a voltage close to zero.

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

[0075] Any of the freewheeling diodes referred to herein may be implemented with synchronous rectifiers. In controlling the soft switching circuit and implementing the waveforms, a synchronous rectifier will be referred to as the switching unit S. The switching unit S described herein is not limited to being implemented by a metal oxide field effect transistor (MOSFET). Preferably, the switching unit S is a MOSFET, and hereinafter the MOSFET will be referred to as the switching unit S. Note that a MOSFET device has a parasitic body diode and a parasitic output capacitor. The presence of the parasitic body diode allows the MOSFET device to act as a synchronous rectifier and take on one of the characteristics of a freewheeling diode. The parasitic output capacitor causes switching loss when the switching unit S switches. By discharging the electricity in the parasitic output capacitor and then controlling the turn-on of the switching unit S, one of the important means and purposes of the soft switching circuit is realized, and the switching loss is reduced.

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

[0079]

number

[0080] where 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.

[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 begins to decrease as the current iLa flowing through the auxiliary inductance La is subtracted from the current iL flowing through the main inductor L. Because the inductance of the auxiliary inductance La is small, its charging speed is fast, and when iLa is greater than iL, the current flowing through the freewheeling diode D becomes zero, allowing the reverse recovery loss of the freewheeling diode D to be significantly reduced.

[0082] If the auxiliary switching element 1111 is implemented as a synchronous rectifier, the synchronous rectifier starts to pass a reverse current. Then, the control signal Gd of the synchronous rectifier is turned off, and the parasitic output capacitor of the auxiliary switching element 111 is discharged with a reverse current. After discharging to zero, the parasitic body diode of the switching unit S starts to circulate. At this time, the voltage Vd across the switching unit S is 0, and Gs is controlled to a high level, thereby realizing zero-voltage conduction of the switching unit S.

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

[0084]

number

[0085] The step-down circuit is V in V o Because 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 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 cut-off loss.

[0086] As can be seen from the waveforms shown in Figure 4, the soft switching circuit of the present invention maintains a continuous current through the main power inductor L with a small ripple, which does not affect the RMS and peak current magnitudes and therefore does not affect the conduction and interruption losses of the switching circuit. At the same time, the auxiliary inductance current of the soft switching circuit only operates when the switching interval is relatively short, which reduces the unnecessary conduction loss of the soft switching circuit and allows the auxiliary inductance current to automatically discharge to zero, achieving zero current interruption and eliminating unnecessary interruption losses.

[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 as follows:

[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 shown in FIG. 5 is often used in general step-down applications where 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 achieving a better soft switching effect.

[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 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. By controlling the on / off of the switching element S to charge and discharge the main inductance L, 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 electrically connected between the switching unit S and the anode of the freewheeling diode D 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; 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 freewheeling diode D is a synchronous rectifier, and Ga is the control signal waveform of the auxiliary switching element 111. Vd is the voltage across both ends of 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 terminal becomes equal to the output voltage V o and the voltage across the main inductor L, 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 using 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, which greatly reduces the reverse recovery loss of the freewheeling diode D. If the freewheeling diode D is implemented as a synchronous rectifier, a reverse current begins to flow through the synchronous rectifier as the freewheeling diode D. After that, 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 until it discharges to zero, after which 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 zero, and Gs can be controlled to a high level to realize the zero-voltage turn-on of the switch unit S.

[0100] After the switch unit S is turned on, the switching voltage terminal A is grounded, the level of the switching voltage terminal A is 0, and the voltage V across the main inductor L 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 using 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 cut-off and has no cut-off loss.

[0103] FIG. 8 is a schematic diagram of a third embodiment of a 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. An inverter circuit consisting 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 a transformer T1 and then rectified by a bridge rectifier circuit consisting of rectifier diodes D1-D4 to obtain a secondary switching voltage. The secondary switching voltage is then low-pass filtered by a main inductance L and a main output capacitor Co to obtain an 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 terminal of the power supply component, the first pole of the main storage capacitor C0 is electrically connected to the second voltage terminal B of the soft switching circuit 300, and the second voltage terminal 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] Figure 9 shows the waveforms of control signals of a specific soft switching circuit according to the embodiment of the present invention shown in Figure 8. In Figure 9, G1 is the control signal waveform of the main switches S1 and S4, and G2 is the control signal waveform of the main switches S2 and S3. Gd1 is the control signal waveform when the secondary rectifier diodes D1 and D4 use synchronous rectifiers, and Gd2 is the control signal waveform when the secondary rectifier diodes D2 and D3 use 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 Figure 8.

[0106] Specifically, Fig. 10 shows waveforms realized in the specific soft switching circuit of the embodiment of the present invention shown in Fig. 8. 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 charging, and the current iLa through the auxiliary inductance La is greater than the current iL through the main inductance L, the current through the rectifier diodes D1-D4 becomes zero, significantly reducing the reverse recovery loss of the rectifier diodes. If the rectifier diodes are implemented as synchronous rectifiers, the synchronous rectifiers begin to pass a reverse current. Then, the control signal Gd2 for the synchronous rectifiers D2 and D3 is turned off. The reverse current is then transferred by D1 and D4 to the main winding through the isolation transformer T1, discharging the parasitic output capacitor of the main switching transistor S. 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 across the main switching transistors S1 and S4 is zero, and Gs is driven high, achieving zero-voltage turn-on of the main switching transistors S1 and S4. A similar process occurs in the next cycle, achieving zero-voltage turn-on of the main switches S2 and S3.

[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 equal to the output voltage V of the DC power supply unit 211. in The level of the switching voltage terminal A shown in Figure 8, which is the output of the 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.

[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 cut-off loss.

[0114] 11 and 12 are schematic diagrams of a fourth embodiment of a power supply component provided by the present application. The power supply component shown in Fig. 11 and 12 is a reverse non-isolated buck-boost circuit, in which the output voltage is reverse to the input voltage due to 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 supplied from the DC power supply unit 211. in (when the main switching unit S is on) and the output voltage V o The input voltage V is electrically connected to the switching voltage end A of the soft switching circuit 300 so that the voltage at the switching voltage end A switches between two levels (when the main switching unit S is off). 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. 12, the output voltage V 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 buck circuit, in which, when the main switching transistors S1 and S3 are on, the input voltage V inThe output inductor is powered by the switching capacitor Cs in series with the main switching transistors S2 and S4. When the main switching transistors S2 and S4 are on, the output inductor is powered by the switching capacitor Cs. The voltage of the switching capacitor Cs is half of the input voltage. Therefore, a multi-level switched-capacitor scheme 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 in (When S1 and S2 are on), 1 / 2V in It can be switched between three levels: zero (when S1, S3 or S2, S4 are on) and zero (when S3, S4 are on). The output voltage is the second voltage terminal B of the soft switching circuit 300. The input and output voltages are referenced to the first voltage terminal 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 multilevel boost circuit, similar to the embodiment shown in FIG. 13, in which the voltage of the switching capacitor Cs is half of the output voltage Vo, and the Vds voltage of the main switching transistors S1 to 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: (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 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 the 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, which is often used in communication systems. The operation method is similar to the embodiments shown in Figures 11 and 12, and the reverse direction of the output voltage is achieved by reverse charging and discharging of the main inductance L. Similar to the embodiments shown in Figures 13 and 14, the voltage of the switching capacitor Cs is half the input / output voltage difference, and the switching capacitor Cs reduces the Vds voltage of the main switching transistors S1 to S4 to (Vo-Vin) / 2. In the embodiment shown in Figure 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] 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 in the first aspect of the present application, and the control method comprising: When the switching voltage end receives a first level signal, controlling the auxiliary module to charge the auxiliary module with the 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 aspect, 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, systems, and functional modules / units in the devices disclosed above can be implemented as software, firmware, hardware, or any suitable combination thereof. In hardware embodiments, the division between 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, digital signal processor, or 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 desired information and that can be accessed by a computer. Additionally, those skilled in the art will know 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 can include any information delivery media.

[0122] Although illustrative embodiments are disclosed and specific terms are used herein, they are used in a general descriptive manner only and should be construed as such and not for purposes of limitation. It will be apparent to those skilled in the art that, unless expressly indicated otherwise, in some embodiments, features, characteristics, and / or elements described in connection with a particular embodiment can be used alone or in combination with features, characteristics, and / or elements described in connection with other embodiments. Accordingly, those skilled in the art will recognize that changes in form and detail may be made without departing from the scope of the present application, as defined by the appended claims.

Claims

1. A soft switching circuit, comprising: The soft switching circuit includes a switching voltage terminal, a main inductance, and a second voltage terminal, wherein the switching voltage terminal is electrically connected to a first terminal of the main inductance, and the second voltage terminal is electrically connected to a second terminal of the main inductance; the soft switching circuit further includes an auxiliary module and a first voltage terminal, wherein the auxiliary module is connected in series between the switching voltage terminal and the first voltage terminal; The auxiliary module includes an auxiliary inductor and a control unit connected in series with the auxiliary inductor, the auxiliary inductor being magnetically coupled to the main inductor and superimposing a coupling voltage on the main inductor; The auxiliary module is configured to charge the auxiliary module using a superposition of a first voltage input by the first voltage end and the coupling voltage with the main inductance 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, the first level signal and the second level signal being different from each other; The control unit includes an auxiliary switching element, and the auxiliary switching element is connected in series between the auxiliary inductance and the first voltage end. Soft switching circuit.

2. 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, thereby charging the auxiliary inductance; The control unit is further configured to control disconnection of 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 is wound around the core of the main inductance.

2. The soft switching circuit of claim 1.

4. The control unit further includes a controller; 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; 3. The soft switching circuit of claim 2.

5. the control unit further includes a unidirectional conducting element connected in series with the auxiliary switching element, the unidirectional conducting 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, and control the auxiliary switching element to be turned off.

5. The soft switching circuit of claim 4.

6. The unidirectional conducting element is a diode.

6. The soft switching circuit of claim 5.

7. 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 for discharge.

3. The soft switching circuit of claim 2.

8. A power supply component including a body circuit and a soft switching circuit, The soft switching circuit is a soft switching circuit according to claim 1, The main circuit includes a power supply module, a total output capacitor, and a power supply output terminal, wherein 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, and 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, and 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 supply components.

9. 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 switching 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 electrically connected to the switching voltage end, an anode of the freewheeling diode electrically connected to the reference voltage end, and a cathode of the freewheeling diode 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 first voltage terminal is electrically connected to the reference voltage terminal and electrically connected to one of the anodes of the DC power supply unit; 9. The power supply component of claim 8.

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 second voltage terminal, and the cathode of the DC power supply unit is electrically connected to a reference voltage terminal; One end of the switching unit is electrically connected to the switching voltage end, and the other end of the switching unit is electrically connected to a reference voltage end; an anode of the freewheeling diode electrically connected to one end of the switching unit, and a cathode of the freewheeling diode electrically connected to a first pole of the total output capacitor; the first voltage terminal is electrically connected to the reference voltage terminal; 9. The power supply component of claim 8.

11. The power supply module includes a DC power supply unit, an inverter unit, a transformer unit, and a rectifier unit, wherein the two input ends of the inverter unit are electrically connected to the anode and cathode of the DC power supply unit, 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 unit; and the output end of the rectifier unit is electrically connected to the switching voltage end; 9. The power supply component of claim 8.

12. 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 electrically connected to a reference voltage terminal, a cathode of the DC power supply unit electrically connected to one end of the switching unit, and another end of the switching unit electrically connected to the switching voltage terminal; The anode of the freewheeling diode is electrically connected to the switching voltage terminal, and the 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 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; 9. The power supply component of claim 8.

13. 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; an anode of the DC power supply unit electrically connected to one end of a first of a plurality of switching elements connected in series, and a cathode of the DC power supply unit electrically connected to the reference voltage terminal; 9. The power supply component of claim 8.

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 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 one of the plurality of switching elements connected in series and a second to last switching element; the switching voltage terminal is electrically connected to an electrical connection node between two switching elements located at an intermediate position among a plurality of switching elements connected in series, the second voltage terminal is electrically connected to an anode of the DC power supply unit, and the first voltage terminal is electrically connected to a reference voltage terminal; The cathode of the DC power supply unit is electrically connected to the reference voltage terminal; 9. The power supply component of claim 8.

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 one of the plurality of switching elements connected in series and a second to last switching element; the switching voltage end is electrically connected to an electrical connection node between two switching elements located at an intermediate 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; 9. The power supply component of claim 8.

16. 1. A method for controlling a soft switching circuit, comprising: The soft switching circuit is a soft switching circuit according to claim 1, 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; When the switching voltage end receives a second level signal, controlling the auxiliary module to discharge the switching voltage end. A method for controlling a soft switching circuit.

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