Voltage conversion circuit

Abstract

The utility model discloses a voltage conversion circuit. The voltage conversion circuit comprises a power supply processing circuit and a step-down circuit. The input end of the power processing circuit is connected with a high-voltage direct-current power supply, the output end of the power processing circuit is connected with the input end of the step-down circuit, and the output end of the step-down circuit is connected with the power supply end of the single-chip microcomputer. Wherein the power supply processing circuit is used for carrying out reverse connection prevention protection, overcurrent protection, electromagnetic power supply interference suppression and voltage filtering processing on high-voltage direct-current voltage output by a high-voltage direct-current power supply to obtain processed high-voltage direct-current voltage, and the step-down circuit is used for carrying out step-down processing on the high-voltage direct-current voltage to obtain 3.3 V direct-current voltage. And the 3.3 V DC voltage is used for supplying power to the single-chip microcomputer.

Description

Technical Field

[0001] The utility model relates to the technical field of single-chip microcomputers, and particularly relates to a voltage conversion circuit. Background Art

[0002] At present, single-chip microcomputers are widely used in various industrial control fields to achieve data processing and functional requirements. Most single-chip microcomputers are powered by DC 3.3V because single-chip microcomputers usually work in cooperation with various DC devices with different voltage values. This diverse voltage requirement poses relatively high adaptability requirements for the power supply circuit of the single-chip microcomputer. A power supply circuit with good adaptability can not only effectively reduce costs, but also reduce the workload of on-site implementation, and improve the reliability and efficiency of the overall system.

[0003] In the prior art, the adaptability of the power supply circuit of the single-chip microcomputer still has deficiencies, resulting in the need for additional power conversion devices or complex power management circuits in actual applications, increasing the complexity and cost of the system; at the same time, the power supply adaptation problem between different voltage devices may also cause potential hazards to the stability and safety of the system, and the safety is poor. Summary of the Utility Model

[0004] Therefore, the embodiment of the utility model provides a voltage conversion circuit to solve the problem that the power supply adaptation problem between different voltage devices in the prior art may also cause potential hazards to the stability and safety of the system, and the safety is poor.

[0005] In order to achieve the above purpose, the embodiment of the utility model provides the following technical solutions:

[0006] A voltage conversion circuit, characterized by comprising a power supply processing circuit and a step-down circuit;

[0007] The input end of the power supply processing circuit is connected to a high-voltage DC power supply, the output end of the power supply processing circuit is connected to the input end of the step-down circuit, and the output end of the step-down circuit is connected to the power supply end of the single-chip microcomputer;

[0008] Wherein, the power supply processing circuit is used for performing reverse connection protection, overcurrent protection, electromagnetic power interference suppression and voltage filtering processing on the high-voltage DC voltage output by the high-voltage DC power supply to obtain a processed high-voltage DC voltage, and the step-down circuit is used for performing step-down processing on the high-voltage DC voltage to obtain a 3.3V DC voltage and supplying power to the single-chip microcomputer by using the 3.3V DC voltage.

[0009] Optionally, the power supply processing circuit includes a PCB terminal CN6, and the model of the PCB terminal is DB142V-5.08-3P-GN.

[0010] Optionally, the first pin of the PCB terminal is divided into eight paths. One path is connected to one end of the twenty-ninth capacitor C29, another path is connected to one end of the first resistor RV1, the third path is connected to one end of the twenty-first capacitor C21, the fourth path is connected to the anode of the seventh diode D7, the fifth path is connected to one end of the thirty-sixth capacitor C36, the sixth path is connected to the negative electrode of the eleventh capacitor C11, the seventh path is connected to one end of the thirty-seventh capacitor C37, and the eighth path is grounded; the second pin of the PCB terminal is connected to one end of the fuse F1; the third pin of the PCB terminal is left floating;

[0011] The other end of the fuse F1 is divided into four paths. One path is connected to one end of the twentieth capacitor C20, another path is connected to the other end of the first resistor RV1, the third path is connected to the other end of the twenty-first capacitor C21, and the fourth path is connected to the anode of the third diode D3;

[0012] The other end of the twentieth capacitor C20 is divided into two paths. One path is connected to the other end of the twenty-ninth capacitor C29, and the other path is connected to the PE network;

[0013] The cathode of the third diode D3 is divided into four paths. One path is connected to the cathode of the seventh diode D7, another path is connected to the other end of the thirty-sixth capacitor C36, the third path is connected to the positive electrode of the eleventh capacitor C11, and the fourth path is connected to one end of the first inductor L1. The other end of the first inductor L1 is divided into two paths. One path is connected to the other end of the thirty-seventh capacitor C37, and the other path is the output end of the power processing circuit.

[0014] Optionally, the buck circuit includes a first buck chip U8 and a second buck chip U7. The model of the first buck chip U8 is LM5013QDDARQ1, and the model of the second buck chip U7 is AMS1117-3.3.

[0015] Optionally, the first pin of the first step-down chip U8 is grounded; the second pin of the first step-down chip U8 is divided into three paths, one path is connected to one end of the thirty-fourth capacitor C34, another path is connected to one end of the thirty-third capacitor C33, and the third path is connected to the output end of the power supply processing circuit; the third pin of the first step-down chip U8 is connected to the second pin of the first step-down chip U8; the fourth pin of the first step-down chip U8 is grounded through the twenty-third resistor R23; the fifth pin of the first step-down chip U8 is divided into three paths, one path is connected to one end of the thirty-fifth capacitor C35, another path is connected to one end of the twenty-second resistor R22, and the third path is connected to one end of the twenty-fourth resistor R24; the sixth pin of the first step-down chip U8 is left floating; the seventh pin of the first step-down chip U8 is connected to one end of the thirtieth capacitor C30; the eighth pin of the first step-down chip U8 is divided into four paths, one path is connected to the other end of the thirtieth capacitor C30, another path is connected to the cathode of the fifth diode D5, the third path is connected to one end of the twenty-first resistor R21, and the fourth path is connected to one end of the second inductor L2;

[0016] The other end of the second inductor L2 is divided into four paths, one path is connected to one end of the thirty-second capacitor C32, another path is connected to the other end of the twenty-second resistor R22, the third path is grounded through the thirty-first capacitor C31, and the fourth path is connected to the +5V voltage output end;

[0017] The other end of the twenty-first resistor R21 is divided into two paths, one path is connected to the other end of the thirty-fifth capacitor C35, and the other path is connected to the other end of the thirty-second capacitor C32;

[0018] The other ends of the thirty-fourth capacitor C34, the thirty-third capacitor C33, and the twenty-fourth resistor R24 are all grounded; the anode of the fifth diode D5 is grounded.

[0019] Optionally, the first pin of the second step-down chip U7 is grounded; the second pin of the second step-down chip U7 is connected to the fourth pin of the second step-down chip U7; the third pin of the second step-down chip U7 is divided into three paths, one path is connected to one end of the thirty-eighth capacitor C38, another path is connected to one end of the twenty-fifth capacitor C25, and the third path is connected to the +5V voltage output end; the fourth pin of the second step-down chip U7 is divided into five paths, one path is connected to the positive electrode of the twenty-sixth capacitor C26, another path is connected to one end of the twenty-seventh capacitor C27, the third path is connected to one end of the twenty-eighth capacitor C28, the fourth path is connected to the cathode of the fourth diode D4, and the fifth path is connected to the power supply terminal of the single-chip microcomputer;

[0020] The other end of the thirty-eighth capacitor C38, the other end of the twenty-fifth capacitor C25, the negative electrode of the twenty-sixth capacitor C26, the other end of the twenty-seventh capacitor C27, the other end of the twenty-eighth capacitor C28, and the anode of the fourth diode D4 are all grounded.

[0021] Optionally, the first resistor RV1 is a 07D560K varistor.

[0022] Optionally, the third diode D3 is an SS58 Schottky diode.

[0023] Optionally, the seventh diode D7 is an SMBJ60A unidirectional TVS diode.

[0024] Optionally, the fourth diode D4 is an SMAJ3.3A unidirectional TVS diode.

[0025] The present utility model has at least the following beneficial effects: Through the combined design of the power supply processing circuit and the buck circuit, this voltage conversion circuit can effectively process high-voltage DC power supplies and convert them into 3.3V DC voltage, providing stable power support for the single-chip microcomputer. The power supply processing circuit includes functions such as reverse connection protection, overcurrent protection, electromagnetic interference suppression, and voltage filtering, enabling it to adapt to various high-voltage DC power supply environments, ensuring the normal operation of the single-chip microcomputer under different working conditions, and realizing a circuit that improves the adaptability of the input voltage of the single-chip microcomputer power supply circuit, with a minimum DC input of 10V, a maximum DC input of 60V, a fixed DC output of 3.3V, and a maximum current of 800mA at the 3.3V voltage terminal. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the prior art and the present utility model, the following will briefly introduce the drawings required for the description of the prior art and the embodiments of the present utility model. Obviously, the drawings in the following description are only exemplary, and those of ordinary skill in the art can also obtain other drawings based on the provided drawings without creative efforts.

[0027] The structures, ratios, sizes, etc. illustrated in this specification are only used to cooperate with the content disclosed in the specification for those familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present utility model. Any modification of the structure, change in the proportional relationship, or adjustment of the size, without affecting the effects that the present utility model can produce and the purposes that can be achieved, should still fall within the scope covered by the technical content disclosed in the present utility model.

[0028] Figure 1 It is a circuit principle block diagram of a voltage conversion circuit provided by an embodiment of the present utility model;

[0029] Figure 2 One of the circuit schematic diagrams of a voltage conversion circuit provided by an embodiment of the present invention;

[0030] Figure 3 Another circuit schematic diagram of a voltage conversion circuit provided by an embodiment of the present invention;

[0031] Figure 4 The third circuit schematic diagram of a voltage conversion circuit provided by an embodiment of the present invention. Detailed implementation manners

[0032] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0033] In the description of the present invention, unless otherwise specified, the meaning of "a plurality of" is two or more. Terms such as "first", "second", "third", "fourth", etc. (if any) in the description and claims of the present invention and the above-mentioned drawings are intended to distinguish the objects being referred to. For a solution with a time sequence process, such a term expression does not necessarily need to be understood as describing a specific order or sequence. For a solution of a device structure, such a term expression also does not distinguish the importance degree, positional relationship, etc.

[0034] In addition, terms such as "include", "have" and any of their variations are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device including a series of steps or units does not necessarily need to be limited to those clearly listed steps or units, but may also include other steps or units inherent to these processes, methods, products or devices that are not clearly listed, or steps or units added by further optimized solutions based on the concept of the present invention.

[0035] This embodiment provides a voltage conversion circuit, including a power supply processing circuit and a step-down circuit;

[0036] The input end of the power supply processing circuit is connected to a high-voltage DC power supply, the output end of the power supply processing circuit is connected to the input end of the step-down circuit, and the output end of the step-down circuit is connected to the power supply end of the single-chip microcomputer;

[0037] Among them, the power supply processing circuit is used to perform reverse connection protection, over-current protection, electromagnetic power interference suppression and voltage filtering processing on the high-voltage DC voltage output by the high-voltage DC power supply to obtain a processed high-voltage DC voltage. The step-down circuit is used to step down the high-voltage DC voltage to obtain a 3.3V DC voltage and supply power to the single-chip microcomputer using the 3.3V DC voltage.

[0038] In this embodiment, the power supply processing circuit includes a PCB terminal CN6, and the model of the PCB terminal is DB142V-5.08-3P-GN.

[0039] In this embodiment, the first pin of the PCB terminal is divided into eight paths. One path is connected to one end of the twenty-ninth capacitor C29, another path is connected to one end of the first resistor RV1, the third path is connected to one end of the twenty-first capacitor C21, the fourth path is connected to the anode of the seventh diode D7, the fifth path is connected to one end of the thirty-sixth capacitor C36, the sixth path is connected to the negative electrode of the eleventh capacitor C11, the seventh path is connected to one end of the thirty-seventh capacitor C37, and the eighth path is grounded; the second pin of the PCB terminal is connected to one end of the fuse F1; the third pin of the PCB terminal is left floating;

[0040] The other end of the fuse F1 is divided into four paths. One path is connected to one end of the twentieth capacitor C20, another path is connected to the other end of the first resistor RV1, the third path is connected to the other end of the twenty-first capacitor C21, and the fourth path is connected to the anode of the third diode D3;

[0041] The other end of the twentieth capacitor C20 is divided into two paths. One path is connected to the other end of the twenty-ninth capacitor C29, and the other path is connected to the PE network;

[0042] The cathode of the third diode D3 is divided into four paths. One path is connected to the cathode of the seventh diode D7, another path is connected to the other end of the thirty-sixth capacitor C36, the third path is connected to the positive electrode of the eleventh capacitor C11, and the fourth path is connected to one end of the first inductor L1. The other end of the first inductor L1 is divided into two paths. One path is connected to the other end of the thirty-seventh capacitor C37, and the other path is the output end of the power supply processing circuit.

[0043] In this embodiment, the buck circuit includes a first buck chip U8 and a second buck chip U7. The model of the first buck chip U8 is LM5013QDDARQ1, and the model of the second buck chip U7 is AMS1117-3.3.

[0044] In this embodiment, the first pin of the first step-down chip U8 is grounded; the second pin of the first step-down chip U8 is divided into three paths, one path is connected to one end of the thirty-fourth capacitor C34, another path is connected to one end of the thirty-third capacitor C33, and the third path is connected to the output end of the power supply processing circuit; the third pin of the first step-down chip U8 is connected to the second pin of the first step-down chip U8; the fourth pin of the first step-down chip U8 is grounded through the twenty-third resistor R23; the fifth pin of the first step-down chip U8 is divided into three paths, one path is connected to one end of the thirty-fifth capacitor C35, another path is connected to one end of the twenty-second resistor R22, and the third path is connected to one end of the twenty-fourth resistor R24; the sixth pin of the first step-down chip U8 is floating; the seventh pin of the first step-down chip U8 is connected to one end of the thirtieth capacitor C30; the eighth pin of the first step-down chip U8 is divided into four paths, one path is connected to the other end of the thirtieth capacitor C30, another path is connected to the cathode of the fifth diode D5, the third path is connected to one end of the twenty-first resistor R21, and the fourth path is connected to one end of the second inductor L2;

[0045] The other end of the second inductor L2 is divided into four paths, one path is connected to one end of the thirty-second capacitor C32, another path is connected to the other end of the twenty-second resistor R22, the third path is grounded through the thirty-first capacitor C31, and the fourth path is connected to the +5V voltage output terminal;

[0046] The other end of the twenty-first resistor R21 is divided into two paths, one path is connected to the other end of the thirty-fifth capacitor C35, and the other path is connected to the other end of the thirty-second capacitor C32;

[0047] The other ends of the thirty-fourth capacitor C34, the thirty-third capacitor C33, and the twenty-fourth resistor R24 are all grounded; the anode of the fifth diode D5 is grounded.

[0048] In this embodiment, the first pin of the second step-down chip U7 is grounded; the second pin of the second step-down chip U7 is connected to the fourth pin of the second step-down chip U7; the third pin of the second step-down chip U7 is divided into three paths, one path is connected to one end of the thirty-eighth capacitor C38, another path is connected to one end of the twenty-fifth capacitor C25, and the third path is connected to the +5V voltage output terminal; the fourth pin of the second step-down chip U7 is divided into five paths, one path is connected to the positive electrode of the twenty-sixth capacitor C26, another path is connected to one end of the twenty-seventh capacitor C27, the third path is connected to one end of the twenty-eighth capacitor C28, the fourth path is connected to the cathode of the fourth diode D4, and the fifth path is connected to the power supply terminal of the single-chip microcomputer;

[0049] The other end of the 38th capacitor C38, the other end of the 25th capacitor C25, the negative electrode of the 26th capacitor C26, the other end of the 27th capacitor C27, the other end of the 28th capacitor C28, and the anode of the fourth diode D4 are all grounded.

[0050] In this embodiment, the first resistor RV1 is a 07D560K varistor.

[0051] In this embodiment, the third diode D3 is an SS58 Schottky diode.

[0052] In this embodiment, the seventh diode D7 is a SMBJ60A unidirectional TVS diode.

[0053] In this embodiment, the fourth diode D4 is a SMAJ3.3A unidirectional TVS diode.

[0054] In this embodiment, the circuit consists of the following parts:

[0055] High-voltage DC power input and processing circuit: This part of the circuit performs reverse connection protection, overcurrent protection, electromagnetic power interference suppression, and voltage filtering on the input high-voltage direct current.

[0056] As Figure 2 shown, pin 1 of the connector with the part number CN6 of DB142V-5.08-3P-GN is connected to one end of the safety ceramic capacitor with the part number C29, one end of the varistor with the part number RV1 of 07D560K, one end of the safety capacitor with the part number C21, the anode of the unidirectional TVS diode with the part number D7 of SMBJ60A, one end of the chip capacitor with the part number C36, the negative electrode of the chip electrolytic capacitor with the part number U11, one end of the chip capacitor with the part number C37, and is commonly connected to the GND network. Pin 2 is connected to one end of the chip fuse with the part number F1, and pin 3 is left floating; one end of the chip fuse with the part number F1 is connected to one end of the safety ceramic capacitor with the part number C20, one end of the varistor with the part number RV1 of 07D560K, one end of the safety capacitor with the part number C21, and the anode of the Schottky diode with the part number D3 of SS58; one end of the safety ceramic capacitor with the part number C20 is connected to one end of the safety ceramic capacitor with the part number C29 and is commonly connected to the PE network; the cathode of the Schottky diode with the part number D3 of SS58 is connected to the cathode of the unidirectional TVS diode with the part number D7 of SMBJ60A, one end of the chip capacitor with the part number C36, the positive electrode of the chip electrolytic capacitor with the part number U11, and one end of the chip inductor with the part number L1; one end of the chip inductor with the part number L1 is connected to one end of the chip capacitor with the part number C37 and is commonly connected to the VIN network.

[0057] Step-down the high-voltage direct current to 3.3V DC voltage and supply it to the microcontroller circuit: For this part, two IC chips can be used to step down the high-voltage direct current processed by the high-voltage DC power input circuit to a fixed DC 3.3V and supply it to the microcontroller.

[0058] As Figure 2 and Figure 3 shown, pin 1 of the DC-DC chip with the model number LM5013QDDARQ1 at the reference designator U8 is connected to the GND network, pin 2 is connected to pin 3, one end of the chip capacitor C34, and one end of the chip capacitor C33, and they are jointly connected to the VIN network. Pin 4 is connected to one end of the chip resistor R23. Pin 5 is connected to one end of the chip capacitor C35, one end of the chip resistor R22, and one end of the chip resistor R24. Pin 6 is left floating. Pin 7 is connected to one end of the chip capacitor C30. Pin 8 is connected to one end of the chip capacitor C30, the cathode of the Schottky diode B560C at the reference designator D5, one end of the chip inductor L2, and one end of the chip resistor R21. One end of the chip capacitor C33 is connected to one end of the chip capacitor C34 and they are jointly connected to the GND network. One end of the chip resistor R23 is connected to the GND network. One end of the chip inductor L2 is connected to one end of the chip capacitor C32, one end of the chip resistor R22, and one end of the chip capacitor C31, and they are jointly connected to the 5V network. The chip resistor R21 is connected to one end of the chip capacitor C32 and one end of the chip capacitor C35. One end of the chip resistor R22 is connected to one end of the chip resistor R24, and one end of the chip resistor R24 is connected to the GND network. Pin 1 of the linear voltage regulator chip with the model number AMS1117-3.3 at the reference designator U7 is connected to the GND network, pin 2 is connected to pin 4, the positive electrode of the electrolytic capacitor C26, one end of the chip capacitor C27, one end of the chip capacitor C28, and the cathode of the unidirectional TVS diode SMAJ3.3A at the reference designator D4, and they jointly supply power to the microcontroller through the 3.3V network. One end of the chip capacitor C25 is connected to one end of the chip capacitor C38 and they are jointly connected to the GND network. One end of the electrolytic capacitor C26 is connected to one end of the chip capacitor C27, one end of the chip capacitor C28, and the anode of the unidirectional TVS diode SMAJ3.3A at the reference designator D4, and they are jointly connected to the GND network.

[0059] The above several specific embodiments can be combined with each other. For the same or similar concepts or processes, they may not be repeated in some embodiments.

[0060] The technical features of the above embodiments can be combined arbitrarily (as long as there is no contradiction in the combination of these technical features). For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described; these embodiments not explicitly written out should also be considered to be within the scope described in this specification.

[0061] In the foregoing, the present utility model has been described in a relatively specific and detailed manner through general descriptions and specific embodiments. It should be noted that, without departing from the concept of the present utility model, it is obvious that several modifications and improvements can still be made to these specific embodiments, and these all belong to the protection scope of this application. Therefore, the protection scope of the patent of this application shall be subject to the appended claims.

Claims

1. A voltage conversion circuit, characterized in that, It includes a power supply processing circuit and a step-down circuit; The input end of the power supply processing circuit is connected to a high-voltage DC power supply, the output end of the power supply processing circuit is connected to the input end of the step-down circuit, and the output end of the step-down circuit is connected to the power supply end of the single-chip microcomputer; Among them, the power supply processing circuit is used to perform reverse connection protection, overcurrent protection, electromagnetic power interference suppression and voltage filtering processing on the high-voltage DC voltage output by the high-voltage DC power supply to obtain a processed high-voltage DC voltage. The step-down circuit is used to step down the high-voltage DC voltage to obtain a 3.3V DC voltage and supply power to the single-chip microcomputer using the 3.3V DC voltage.

2. The voltage conversion circuit according to claim 1, wherein The power supply processing circuit includes a PCB terminal CN6, and the model of the PCB terminal is DB142V-5.08-3P-GN.

3. The voltage conversion circuit according to claim 2, wherein The first pin of the PCB terminal is divided into eight paths. One path is connected to one end of the twenty-ninth capacitor C29, another path is connected to one end of the first resistor RV1, the third path is connected to one end of the twenty-first capacitor C21, the fourth path is connected to the anode of the seventh diode D7, the fifth path is connected to one end of the thirty-sixth capacitor C36, the sixth path is connected to the negative electrode of the eleventh capacitor C11, the seventh path is connected to one end of the thirty-seventh capacitor C37, and the eighth path is grounded; the second pin of the PCB terminal is connected to one end of the fuse F1; the third pin of the PCB terminal is left floating; The other end of the fuse F1 is divided into four paths. One path is connected to one end of the twentieth capacitor C20, another path is connected to the other end of the first resistor RV1, the third path is connected to the other end of the twenty-first capacitor C21, and the fourth path is connected to the anode of the third diode D3; The other end of the twentieth capacitor C20 is divided into two paths. One path is connected to the other end of the twenty-ninth capacitor C29, and the other path is connected to the PE network; The cathode of the third diode D3 is divided into four paths. One path is connected to the cathode of the seventh diode D7, another path is connected to the other end of the thirty-sixth capacitor C36, the third path is connected to the positive electrode of the eleventh capacitor C11, and the fourth path is connected to one end of the first inductor L1. The other end of the first inductor L1 is divided into two paths. One path is connected to the other end of the thirty-seventh capacitor C37, and the other path is the output end of the power supply processing circuit.

4. A voltage conversion circuit according to claim 1, characterized in that, The step-down circuit includes a first step-down chip U8 and a second step-down chip U7. The model of the first step-down chip U8 is LM5013QDDARQ1, and the model of the second step-down chip U7 is AMS1117-3.

3.

5. A voltage conversion circuit according to claim 4, characterized in that, The first pin of the first step-down chip U8 is grounded; the second pin of the first step-down chip U8 is divided into three paths, one path is connected to one end of the thirty-fourth capacitor C34, another path is connected to one end of the thirty-third capacitor C33, and the third path is connected to the output end of the power supply processing circuit; the third pin of the first step-down chip U8 is connected to the second pin of the first step-down chip U8; the fourth pin of the first step-down chip U8 is grounded through the twenty-third resistor R23; the fifth pin of the first step-down chip U8 is divided into three paths, one path is connected to one end of the thirty-fifth capacitor C35, another path is connected to one end of the twenty-second resistor R22, and the third path is connected to one end of the twenty-fourth resistor R24; the sixth pin of the first step-down chip U8 is floating; the seventh pin of the first step-down chip U8 is connected to one end of the thirtieth capacitor C30; the eighth pin of the first step-down chip U8 is divided into four paths, one path is connected to the other end of the thirtieth capacitor C30, another path is connected to the cathode of the fifth diode D5, the third path is connected to one end of the twenty-first resistor R21, and the fourth path is connected to one end of the second inductor L2; The other end of the second inductor L2 is divided into four paths, one path is connected to one end of the thirty-second capacitor C32, another path is connected to the other end of the twenty-second resistor R22, the third path is grounded through the thirty-first capacitor C31, and the fourth path is connected to the +5V voltage output terminal; The other end of the twenty-first resistor R21 is divided into two paths, one path is connected to the other end of the thirty-fifth capacitor C35, and the other path is connected to the other end of the thirty-second capacitor C32; The other ends of the thirty-fourth capacitor C34, the thirty-third capacitor C33, and the twenty-fourth resistor R24 are all grounded; the anode of the fifth diode D5 is grounded.

6. The voltage conversion circuit according to claim 5, characterized in that, The first pin of the second step-down chip U7 is grounded; the second pin of the second step-down chip U7 is connected to the fourth pin of the second step-down chip U7; the third pin of the second step-down chip U7 is divided into three paths, one path is connected to one end of the thirty-eighth capacitor C38, another path is connected to one end of the twenty-fifth capacitor C25, and the third path is connected to the +5V voltage output terminal; the fourth pin of the second step-down chip U7 is divided into five paths, one path is connected to the positive electrode of the twenty-sixth capacitor C26, another path is connected to one end of the twenty-seventh capacitor C27, the third path is connected to one end of the twenty-eighth capacitor C28, the fourth path is connected to the cathode of the fourth diode D4, and the fifth path is connected to the power supply terminal of the single-chip microcomputer; The other ends of the thirty-eighth capacitor C38, the twenty-fifth capacitor C25, the negative electrode of the twenty-sixth capacitor C26, the other ends of the twenty-seventh capacitor C27, the other ends of the twenty-eighth capacitor C28, and the anode of the fourth diode D4 are all grounded.

7. A voltage conversion circuit according to claim 3, characterized in that The first resistor RV1 is a 07D560K varistor.

8. A voltage conversion circuit according to claim 3, characterized in that, The third diode D3 is an SS58 Schottky diode.

9. A voltage conversion circuit according to claim 3, wherein, The seventh diode D7 is an SMBJ60A unidirectional TVS diode.

10. A voltage conversion circuit according to claim 6, wherein The fourth diode D4 is a SMAJ3.3A unidirectional TVS diode.

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