Auxiliary power supply
By adding two capacitors and two diodes to the secondary side rectifier circuit of the switch mode power converter, a voltage-stable auxiliary power supply is constructed, which solves the problem that the auxiliary power supply needs to introduce magnetic components in the prior art, and achieves the effect of reducing the power supply volume and cost.
Patent Information
- Application Number
- CN202411903950.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-23
- Publication Date
- 2025-04-25
AI Technical Summary
In the prior art, the auxiliary power supply needs to use a transformer or a boost inductor to meet the application situation, thereby introducing magnetic components, resulting in the problem of increasing volume weight.
By adding two capacitors and two diodes to the secondary side rectifier circuit of the switch mode power converter, a voltage-stable auxiliary power supply is constructed without adding magnetic components.
It realizes powering the synchronous rectified MOSFET driver chip without adding magnetic components, effectively reducing the power supply volume and cost.
Smart Images
Figure CN119891769A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of power electronics technology, and in particular to an auxiliary power supply. Background Art
[0002] For switching power supplies, synchronous rectification technology is often used in low-voltage, high-current output applications, that is, MOSFET is used to replace diodes. Since the on-state voltage drop of MOSFET is much smaller than that of diodes, the loss is greatly reduced, the power efficiency is increased, and the size of the heat sink is reduced, which is conducive to reducing the volume and cost of the power supply. However, the operation of MOSFET requires the driver chip to provide an on-off signal, so it is also necessary to add an auxiliary power supply to power the driver chip. The existing technology often adds a small-power auxiliary power supply, which can be powered from the input or the output. If the power is taken from the input, a transformer is required in occasions where isolation is required; if the power is taken from the output, due to the low output voltage (3.3V, 5V application occasions), the output voltage needs to be increased to a suitable voltage to make the MOSFET fully turned on (the MOSFET turn-on voltage threshold is 1-3V, the higher the driving voltage, the smaller the on-resistance), and a boost inductor is required at this time. Whether a transformer or a boost inductor is used, magnetic components will be introduced, resulting in an increase in volume and weight. Summary of the invention
[0003] In view of this, an embodiment of the present application provides an auxiliary power supply, which at least partially solves the problem in the prior art that the auxiliary power supply needs to use a transformer or a boost inductor to meet the application scenario, thereby introducing magnetic components and causing an increase in volume and weight.
[0004] An embodiment of the present application provides an auxiliary power supply, wherein the auxiliary power supply includes a switch mode power converter, wherein the switch mode power converter includes a primary circuit, a secondary rectifier circuit, and a transformer T connected between the primary circuit and the secondary rectifier circuit, wherein the secondary rectifier circuit is configured as a bridge rectifier structure, and the auxiliary power supply also includes a first capacitor C1, a second capacitor C2, a first diode D1, and a second diode D2, wherein an anode of the first diode D1 is connected to a positive electrode of an output terminal, a cathode of the first diode D1 is connected to an anode of the second diode D2, a cathode of the second diode D2 is connected to one end of the second capacitor C2, and the other end of the second capacitor C2 is connected to a negative electrode of the output terminal, one end of the first capacitor C1 is connected to a midpoint of any bridge arm of the bridge rectifier structure, and the other end of the first capacitor C1 is connected to a midpoint between the first diode D1 and the second diode D2.
[0005] According to a specific implementation of the embodiment of the present application, the bridge rectifier structure is set to a full-bridge rectifier structure, including a first switch tube Q1, a second switch tube Q2, a third switch tube Q3, a fourth switch tube Q4 and an output filter capacitor C3, the first switch tube Q1 and the second switch tube Q2 are connected in series and then connected in parallel to the positive electrode of the output terminal and the negative electrode of the output terminal, the drain of the first switch tube Q1 is connected to the positive electrode of the output terminal, and the source of the second switch tube Q2 is connected to the negative electrode of the output terminal; the third switch tube Q3 and the fourth switch The third switch tube Q4 is connected in series and then connected in parallel to the positive electrode of the output terminal and the negative electrode of the output terminal, the drain of the third switch tube Q3 is connected to the positive electrode of the output terminal, and the source of the fourth switch tube Q4 is connected to the negative electrode of the output terminal; one end of the secondary winding of the transformer T is connected to the middle point of the first switch tube Q1 and the second switch tube Q2, the other end of the secondary winding of the transformer T is connected to the middle point of the third switch tube Q3 and the fourth switch tube Q4, and the output filter capacitor C3 is connected in parallel to the positive electrode of the output terminal and the negative electrode of the output terminal.
[0006] According to a specific implementation of the embodiment of the present application, the switch mode power converter is set as a half-bridge LLC converter, and the primary circuit of the half-bridge LLC converter includes a fifth switch tube Q5, a sixth switch tube Q6, a first resonant inductor L r1 , the first resonant capacitor C r1 and the second resonant capacitor C r2 The drain of the fifth switch tube Q5 is connected to the positive electrode of the input terminal, the source of the fifth switch tube Q5 is connected to the drain of the sixth switch tube Q6, the source of the sixth switch tube Q6 is connected to the negative electrode of the input terminal, and the first resonant capacitor C r1 and the second resonant capacitor C r2 After being connected in series, they are then connected in parallel to the positive electrode of the input terminal and the negative electrode of the input terminal. The first resonant inductor L r1 One end of the first resonant inductor L is connected to the middle point of the fifth switch tube Q5 and the sixth switch tube Q6. r1 The other end of the primary winding of the transformer T is connected to one end of the primary winding of the transformer T, and the other end of the primary winding of the transformer T is connected to the first resonant capacitor C r1 and the second resonant capacitor C r2 The middle point.
[0007] According to a specific implementation of an embodiment of the present application, the switch mode power converter is configured as a full-bridge LLC converter, and the primary circuit of the full-bridge LLC converter includes a seventh switch tube Q7, an eighth switch tube Q8, a ninth switch tube Q9, and a tenth switch tube Q 10 , the second resonant inductor L r2 and the third resonant capacitor C r3The seventh switch tube Q7 and the eighth switch tube Q8 are connected in series and then connected in parallel to the positive electrode of the input terminal and the negative electrode of the input terminal. The drain of the seventh switch tube Q7 is connected to the positive electrode of the input terminal, and the source of the eighth switch tube Q8 is connected to the negative electrode of the input terminal; the ninth switch tube Q9 and the tenth switch tube Q 10 After being connected in series, they are connected in parallel to the positive electrode of the input terminal and the negative electrode of the input terminal. The drain of the ninth switch tube Q9 is connected to the positive electrode of the input terminal. 10 The source of the second resonant inductor L is connected to the negative electrode of the input terminal; r2 One end is connected to the ninth switch tube Q9 and the tenth switch tube Q 10 The middle point of the second resonant inductor L r2 The other end of the primary winding of the transformer T is connected to one end of the primary winding of the transformer T, and the other end of the primary winding of the transformer T is connected to the third resonant capacitor C r3 After being connected in series, they are connected to the middle point of the seventh switch tube Q7 and the eighth switch tube Q8.
[0008] According to a specific implementation of the embodiment of the present application, the switch mode power converter is configured as a dual active bridge converter, and the primary circuit of the dual active bridge converter includes an eleventh switch tube Q 11 , the twelfth switch tube Q 12 、Thirteenth switch tube Q 13 , the fourteenth switch tube Q 14 and the third resonant inductor L r3 , the eleventh switch tube Q 11 and the twelfth switch tube Q 12 After being connected in series, they are connected in parallel to the positive electrode of the input terminal and the negative electrode of the input terminal. The eleventh switch tube Q 11 The drain of the twelfth switch tube Q is connected to the positive electrode of the input terminal. 12 The source of the thirteenth switch tube Q is connected to the negative electrode of the input terminal; 13 and the fourteenth switch tube Q 14 After being connected in series, they are connected in parallel to the positive electrode of the input terminal and the negative electrode of the input terminal. The thirteenth switch tube Q 13 The drain of the fourteenth switch tube Q is connected to the positive electrode of the input terminal. 14 The source of is connected to the negative electrode of the input terminal; the third resonant inductor L r3 One end is connected to the thirteenth switch tube Q 13 and the fourteenth switch tube Q 14 The middle point of the third resonant inductor L r3 The other end of the primary winding of the transformer T is connected to one end of the primary winding of the transformer T, and the other end of the primary winding of the transformer T is connected to the eleventh switch tube Q 11 and the twelfth switch tube Q 12 The middle point.
[0009] According to a specific implementation of the embodiment of the present application, the first switch tube Q1, the second switch tube Q2, the third switch tube Q3 and the fourth switch tube Q4 are configured as MOS tubes.
[0010] According to a specific implementation of the embodiment of the present application, each switch tube in the primary circuit is configured as a MOS tube.
[0011] Beneficial effects:
[0012] The auxiliary power supply in the embodiment of the present application can construct a voltage-stable auxiliary power supply by using only two capacitors and two diodes in the circuit. The auxiliary power supply is constructed without adding magnetic components to supply power to the synchronous rectification MOSFET driver chip, thereby effectively reducing the size and cost of the power supply. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0014] Figure 1 A circuit diagram of an auxiliary power supply using a half-bridge LLC converter according to an embodiment of the present invention;
[0015] Figure 2 A circuit diagram of an auxiliary power supply using a full-bridge LLC converter according to an embodiment of the present invention;
[0016] Figure 3 FIG. 4 is a circuit diagram of an auxiliary power supply using a dual active bridge converter according to an embodiment of the present invention. DETAILED DESCRIPTION
[0017] The embodiments of the present application are described in detail below with reference to the accompanying drawings.
[0018] The following describes the implementation methods of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the following embodiments and the features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.
[0019] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present application, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this device and / or practice this method.
[0020] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. The illustrations only show the components related to the present application rather than being drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed at will, and the component layout may also be more complicated.
[0021] Additionally, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the aspects described may be practiced without these specific details.
[0022] The present application embodiment provides an auxiliary power supply. Figures 1 to 3 Describe in detail.
[0023] In one embodiment, the auxiliary power supply includes a switch mode power converter, the switch mode power converter includes a primary circuit, a secondary rectifier circuit and a transformer T connected between the primary circuit and the secondary rectifier circuit, the secondary rectifier circuit is configured as a bridge rectifier structure, the auxiliary power supply also includes a first capacitor C1, a second capacitor C2, a first diode D1 and a second diode D2, the anode of the first diode D1 is connected to the positive electrode of the output terminal, the cathode of the first diode D1 is connected to the anode of the second diode D2, the cathode of the second diode D2 is connected to one end of the second capacitor C2, the other end of the second capacitor C2 is connected to the negative electrode of the output terminal, one end of the first capacitor C1 is connected to the midpoint of any bridge arm of the bridge rectifier structure, and the other end of the first capacitor C1 is connected to the midpoint of the first diode D1 and the second diode D2.
[0024] In a specific implementation, the bridge rectifier structure is set as a full-bridge rectifier structure, including a first switch tube Q1, a second switch tube Q2, a third switch tube Q3, a fourth switch tube Q4 and an output filter capacitor C3, the first switch tube Q1 and the second switch tube Q2 are connected in series and then connected in parallel to the positive electrode of the output terminal and the negative electrode of the output terminal, the drain of the first switch tube Q1 is connected to the positive electrode of the output terminal, and the source of the second switch tube Q2 is connected to the negative electrode of the output terminal; the third switch tube Q3 and the fourth switch tube Q4 are connected in series and then connected in parallel to the positive electrode of the output terminal and the negative electrode of the output terminal. Then connected in parallel to the positive electrode of the output terminal and the negative electrode of the output terminal, the drain of the third switch tube Q3 is connected to the positive electrode of the output terminal, and the source of the fourth switch tube Q4 is connected to the negative electrode of the output terminal; one end of the secondary winding of the transformer T is connected to the middle point of the first switch tube Q1 and the second switch tube Q2, the other end of the secondary winding of the transformer T is connected to the middle point of the third switch tube Q3 and the fourth switch tube Q4, and the output filter capacitor C3 is connected in parallel to the positive electrode of the output terminal and the negative electrode of the output terminal.
[0025] In this embodiment, the secondary side of the switch mode power converter is a full-bridge rectifier structure, and the diode is replaced by a MOSFET, wherein the first capacitor C1 can be connected to the midpoint of any bridge arm, that is, the drain of the second switch tube Q2 or the drain of the fourth switch tube Q4, the first diode D1, the second diode D2, and the second capacitor C2 are connected in series, the first capacitor C1 is connected to the midpoint of the first diode D1 and the second diode D2, the anode of the first diode D1 is connected to the positive electrode of the output terminal, and the second capacitor C2 is connected to the negative electrode of the output terminal. The working principle is as follows: when the secondary voltage of the transformer is positive, the first switch tube Q1 and the fourth switch tube Q4 are turned on, and the secondary voltage of the transformer is equal to the output voltage V o At the same time, when the first switch tube Q1 is turned on, the secondary winding of the transformer can charge the first capacitor C1 through the first diode D1, so the voltage across the first capacitor C1 is Vo When the transformer secondary voltage is negative, the second switch tube Q2 and the third switch tube Q3 are turned on, and the transformer secondary voltage is -V o At the same time, when the second switch tube Q2 is turned on, the secondary winding of the transformer can charge the second capacitor C2 through the first capacitor C1 and the second diode D2, so the voltage across the second capacitor C2 is 2V o Therefore, two capacitors and two diodes are added to the circuit, where the voltage V across the second capacitor C2 is aux It can provide driving voltage for MOSFET, and V aux =2V o .
[0026] Therefore, as long as the secondary side of the converter adopts a bridge rectification method, this connection method can be used to construct an auxiliary power supply, and a voltage-stable auxiliary power supply can be constructed by using only two capacitors and two diodes. It has no magnetic components, is simple and reliable, and effectively reduces the size and cost.
[0027] In one embodiment, the switch mode power converter can be set as a half-bridge LLC converter, a full-bridge LLC converter or a dual active bridge converter. It should be noted that the switch mode power converters listed here are only exemplary and have no limitations. They can be adjusted to other forms of switch mode power converters according to actual application conditions, that is, the primary circuit can be set in various forms according to actual application conditions.
[0028] Specifically, refer to Figure 1 The switch mode power converter adopts a half-bridge LLC converter, and the primary circuit of the half-bridge LLC converter includes a fifth switch tube Q5, a sixth switch tube Q6, a first resonant inductor L r1 , the first resonant capacitor C r1 and the second resonant capacitor C r2 The drain of the fifth switch tube Q5 is connected to the positive electrode of the input terminal, the source of the fifth switch tube Q5 is connected to the drain of the sixth switch tube Q6, the source of the sixth switch tube Q6 is connected to the negative electrode of the input terminal, and the first resonant capacitor C r1 and the second resonant capacitor C r2 After being connected in series, they are then connected in parallel to the positive electrode of the input terminal and the negative electrode of the input terminal. The first resonant inductor L r1 One end of the first resonant inductor L is connected to the middle point of the fifth switch tube Q5 and the sixth switch tube Q6. r1 The other end of the primary winding of the transformer T is connected to one end of the primary winding of the transformer T, and the other end of the primary winding of the transformer T is connected to the first resonant capacitor C r1 and the second resonant capacitor C r2 The middle point.
[0029] Specifically, refer to Figure 2 The switch mode power converter adopts a full-bridge LLC converter, and the primary circuit of the full-bridge LLC converter includes a seventh switch tube Q7, an eighth switch tube Q8, a ninth switch tube Q9, and a tenth switch tube Q 10 , the second resonant inductor L r2 and the third resonant capacitor C r3 The seventh switch tube Q7 and the eighth switch tube Q8 are connected in series and then connected in parallel to the positive electrode of the input terminal and the negative electrode of the input terminal. The drain of the seventh switch tube Q7 is connected to the positive electrode of the input terminal, and the source of the eighth switch tube Q8 is connected to the negative electrode of the input terminal; the ninth switch tube Q9 and the tenth switch tube Q 10 After being connected in series, they are connected in parallel to the positive electrode of the input terminal and the negative electrode of the input terminal. The drain of the ninth switch tube Q9 is connected to the positive electrode of the input terminal. 10 The source of the second resonant inductor L is connected to the negative electrode of the input terminal; r2 One end is connected to the ninth switch tube Q9 and the tenth switch tube Q 10 The middle point of the second resonant inductor L r2 The other end of the primary winding of the transformer T is connected to one end of the primary winding of the transformer T, and the other end of the primary winding of the transformer T is connected to the third resonant capacitor C r3 After being connected in series, they are connected to the middle point of the seventh switch tube Q7 and the eighth switch tube Q8.
[0030] Specifically, refer to Figure 3 The switch mode power converter adopts a dual active bridge converter, wherein the primary circuit of the dual active bridge converter includes an eleventh switch tube Q 11 , the twelfth switch tube Q 12 、Thirteenth switch tube Q 13 , the fourteenth switch tube Q 14 and the third resonant inductor L r3 , the eleventh switch tube Q 11 and the twelfth switch tube Q 12 After being connected in series, they are connected in parallel to the positive electrode of the input terminal and the negative electrode of the input terminal. The eleventh switch tube Q 11 The drain of the twelfth switch tube Q is connected to the positive electrode of the input terminal. 12 The source of the thirteenth switch tube Q is connected to the negative electrode of the input terminal; 13 and the fourteenth switch tube Q 14 After being connected in series, they are connected in parallel to the positive electrode of the input terminal and the negative electrode of the input terminal. The thirteenth switch tube Q 13 The drain of the fourteenth switch tube Q is connected to the positive electrode of the input terminal. 14 The source of is connected to the negative electrode of the input terminal; the third resonant inductor L r3 One end is connected to the thirteenth switch tube Q 13and the fourteenth switch tube Q 14 The middle point of the third resonant inductor L r3 The other end of the primary winding of the transformer T is connected to one end of the primary winding of the transformer T, and the other end of the primary winding of the transformer T is connected to the eleventh switch tube Q 11 and the twelfth switch tube Q 12 The middle point.
[0031] In one embodiment, the first switch tube Q1, the second switch tube Q2, the third switch tube Q3 and the fourth switch tube Q4 are configured as MOS tubes.
[0032] In one embodiment, each switch tube in the primary circuit is configured as a MOS tube.
[0033] In the embodiment provided by the present invention, two capacitors and two diodes are added to the secondary rectifier circuit. When the secondary voltage of the transformer is positive, the first switch tube Q1 and the fourth switch tube Q4 are turned on, and the secondary voltage of the transformer is equal to the output voltage V o At the same time, when the first switch tube Q1 is turned on, the secondary winding of the transformer can charge the first capacitor C1 through the first diode D1, so the voltage across the first capacitor C1 is V o When the transformer secondary voltage is negative, the second switch tube Q2 and the third switch tube Q3 are turned on, and the transformer secondary voltage is -V o At the same time, when the second switch tube Q2 is turned on, the secondary winding of the transformer can charge the second capacitor C2 through the first capacitor C1 and the second diode D2, so the voltage across the second capacitor C2 is 2V o Therefore, two capacitors and two diodes are added to the circuit, where the voltage V across the second capacitor C2 is aux It can provide driving voltage for MOSFET, and V aux =2V o Therefore, the present application can construct a voltage-stable auxiliary power supply by only using two capacitors and two diodes, without magnetic components, which is simple and reliable, and effectively reduces the volume and cost.
[0034] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.
Claims
1. An auxiliary power supply, characterized in that: The auxiliary power supply includes a switch mode power converter, which includes a primary circuit, a secondary rectifier circuit and a transformer T connected between the primary circuit and the secondary rectifier circuit. The secondary rectifier circuit is set to a bridge rectifier structure. The auxiliary power supply also includes a first capacitor C1, a second capacitor C2, a first diode D1 and a second diode D2. The anode of the first diode D1 is connected to the positive electrode of the output terminal, the cathode of the first diode D1 is connected to the anode of the second diode D2, the cathode of the second diode D2 is connected to one end of the second capacitor C2, the other end of the second capacitor C2 is connected to the negative electrode of the output terminal, one end of the first capacitor C1 is connected to the midpoint of any bridge arm of the bridge rectifier structure, and the other end of the first capacitor C1 is connected to the midpoint of the first diode D1 and the second diode D2.
2. The auxiliary power supply according to claim 1, characterized in that: The bridge rectifier structure is set as a full-bridge rectifier structure, including a first switch tube Q1, a second switch tube Q2, a third switch tube Q3, a fourth switch tube Q4 and an output filter capacitor C3, the first switch tube Q1 and the second switch tube Q2 are connected in series and then connected in parallel to the positive electrode of the output terminal and the negative electrode of the output terminal, the drain of the first switch tube Q1 is connected to the positive electrode of the output terminal, and the source of the second switch tube Q2 is connected to the negative electrode of the output terminal; the third switch tube Q3 and the fourth switch tube Q4 are connected in series and then connected in parallel to the positive electrode of the output terminal and the negative electrode of the output terminal, the drain of the third switch tube Q3 is connected to the positive electrode of the output terminal, and the source of the fourth switch tube Q4 is connected to the negative electrode of the output terminal; one end of the secondary winding of the transformer T is connected to the middle point of the first switch tube Q1 and the second switch tube Q2, the other end of the secondary winding of the transformer T is connected to the middle point of the third switch tube Q3 and the fourth switch tube Q4, and the output filter capacitor C3 is connected in parallel to the positive electrode of the output terminal and the negative electrode of the output terminal.
3. The auxiliary power supply according to claim 1, characterized in that: The switch mode power converter is configured as a half-bridge LLC converter. The primary circuit of the half-bridge LLC converter includes a fifth switch tube Q5, a sixth switch tube Q6, a first resonant inductor L r1 , the first resonant capacitor C r1 and the second resonant capacitor C r2 The drain of the fifth switch tube Q5 is connected to the positive electrode of the input terminal, the source of the fifth switch tube Q5 is connected to the drain of the sixth switch tube Q6, the source of the sixth switch tube Q6 is connected to the negative electrode of the input terminal, and the first resonant capacitor C r1 and the second resonant capacitor C r2 After being connected in series, they are then connected in parallel to the positive electrode of the input terminal and the negative electrode of the input terminal. The first resonant inductor L r1 One end of the first resonant inductor L is connected to the middle point of the fifth switch tube Q5 and the sixth switch tube Q6. r1 The other end of the primary winding of the transformer T is connected to one end of the primary winding of the transformer T, and the other end of the primary winding of the transformer T is connected to the first resonant capacitor C r1 and the second resonant capacitor C r2 The middle point.
4. The auxiliary power supply according to claim 1, characterized in that: The switch mode power converter is configured as a full-bridge LLC converter, and the primary circuit of the full-bridge LLC converter includes a seventh switch tube Q7, an eighth switch tube Q8, a ninth switch tube Q9, a tenth switch tube Q 10 , the second resonant inductor L r2 and the third resonant capacitor C r3 The seventh switch tube Q7 and the eighth switch tube Q8 are connected in series and then connected in parallel to the positive electrode of the input terminal and the negative electrode of the input terminal. The drain of the seventh switch tube Q7 is connected to the positive electrode of the input terminal, and the source of the eighth switch tube Q8 is connected to the negative electrode of the input terminal; the ninth switch tube Q9 and the tenth switch tube Q 10 After being connected in series, they are connected in parallel to the positive electrode of the input terminal and the negative electrode of the input terminal. The drain of the ninth switch tube Q9 is connected to the positive electrode of the input terminal. 10 The source of the second resonant inductor L is connected to the negative electrode of the input terminal; r2 One end is connected to the ninth switch tube Q9 and the tenth switch tube Q 10 The middle point of the second resonant inductor L r2 The other end of the primary winding of the transformer T is connected to one end of the primary winding of the transformer T, and the other end of the primary winding of the transformer T is connected to the third resonant capacitor C r3 After being connected in series, they are connected to the middle point of the seventh switch tube Q7 and the eighth switch tube Q8.
5. The auxiliary power supply according to claim 1, characterized in that: The switch mode power converter is configured as a dual active bridge converter, and the primary circuit of the dual active bridge converter includes an eleventh switch tube Q 11 , the twelfth switch tube Q 12 、Thirteenth switch tube Q 13 , the fourteenth switch tube Q 14 and the third resonant inductor L r3 , the eleventh switch tube Q 11 and the twelfth switch tube Q 12 After being connected in series, they are connected in parallel to the positive electrode of the input terminal and the negative electrode of the input terminal. The eleventh switch tube Q 11 The drain of the twelfth switch tube Q is connected to the positive electrode of the input terminal. 12 The source of the thirteenth switch tube Q is connected to the negative electrode of the input terminal; 13 and the fourteenth switch tube Q 14 After being connected in series, they are connected in parallel to the positive electrode of the input terminal and the negative electrode of the input terminal. The thirteenth switch tube Q 13 The drain of the fourteenth switch tube Q is connected to the positive electrode of the input terminal. 14 The source of is connected to the negative electrode of the input terminal; the third resonant inductor L r3 One end is connected to the thirteenth switch tube Q 13 and the fourteenth switch tube Q 14 The middle point of the third resonant inductor L r3 The other end of the primary winding of the transformer T is connected to one end of the primary winding of the transformer T, and the other end of the primary winding of the transformer T is connected to the eleventh switch tube Q 11 and the twelfth switch tube Q 12 The middle point.
6. The auxiliary power supply according to claim 2, characterized in that: The first switch tube Q1, the second switch tube Q2, the third switch tube Q3 and the fourth switch tube Q4 are configured as MOS tubes.
7. The auxiliary power supply according to any one of claims 3 to 5, characterized in that: Each switch tube in the primary circuit is configured as a MOS tube.