Negative pressure circuit, negative pressure module and negative pressure device

Abstract

The utility model is applied to the technical field of power supplies, and discloses a negative voltage circuit, a negative voltage module and a negative voltage device, the negative voltage circuit comprises a control chip, the input end of the control chip is connected with an input voltage end; the first end of the first capacitor is connected with the input voltage end, and the second end of the first capacitor is connected with the input ground end; the first end of the inductor is connected with the control end of the control chip, the second end of the inductor is connected with the input ground end, and the second end of the inductor serves as a first output end; the first end of the diode is connected with the first end of the inductor, and the second end of the diode is connected with the ground end of the control chip; the first end of the second capacitor is connected with the second end of the inductor, the second end of the second capacitor is connected with the ground end of the control chip, and the second end of the second capacitor serves as a second output end. Therefore, the technical problem of high cost of a traditional chip for generating negative voltage from positive voltage is solved.

Description

Technical Field

[0001] The present application relates to the field of power supply technology, and in particular to a negative pressure circuit, a negative pressure module and a negative pressure device. Background Art

[0002] AR smart glasses are derived from augmented reality (AR), a technology that can combine virtual information with the real world. With the improvement of the computing power of portable electronic products, the use of AR technology has become more and more extensive. The goal of this technology is to apply virtual information to the real world and superimpose computer-generated virtual objects, scenes or system prompts on real scenes, thereby enhancing reality.

[0003] Micro LED light machine is one of the display technologies. Micro LED is a technology that thins, miniaturizes and arrays LEDs. The components of the display array are LED light-emitting units with a size of 1 to 60μm. In the application of Micro LED light machine backlight negative pressure technology, it mainly involves the design and optimization of negative pressure control circuits. By reasonably designing the negative pressure control circuit, the brightness of the backlight source can be effectively adjusted, thereby achieving a more uniform lighting effect.

[0004] In traditional technology, the dedicated negative voltage DCDC (direct current to direct current conversion) is a chip model LMR70503, which directly generates negative voltage from positive voltage, thereby ensuring the power consumption and stability of the negative voltage control circuit, but the cost of the chip is very high. Utility Model Content

[0005] The main purpose of the present application is to provide a negative pressure circuit, a negative pressure module and a negative pressure device, aiming to solve the technical problem of high cost of traditional chips that generate negative pressure from positive pressure.

[0006] To achieve the above object, the present application provides a negative voltage circuit, the negative voltage circuit comprising:

[0007] A control chip, wherein an input terminal of the control chip is connected to an input voltage terminal;

[0008] A first capacitor, wherein a first end of the first capacitor is connected to the input voltage end, and a second end of the first capacitor is connected to the input ground end;

[0009] an inductor, wherein a first end of the inductor is connected to a control end of the control chip, a second end of the inductor is connected to an input ground end, and the second end of the inductor serves as a first output end;

[0010] a diode, wherein a first end of the diode is connected to a first end of the inductor, and a second end of the diode is connected to a ground terminal of the control chip;

[0011] A second capacitor, wherein a first end of the second capacitor is connected to the second end of the inductor, a second end of the second capacitor is connected to the ground end of the control chip, and the second end of the second capacitor serves as a second output end.

[0012] Optionally, the negative pressure circuit further includes:

[0013] A level conversion module is connected to the input voltage terminal and the enable terminal of the control chip respectively, and is used for receiving an enable signal and sending the signal to the enable terminal of the control chip after performing level conversion.

[0014] Optionally, the level conversion module includes: a first triode and a second triode;

[0015] A first transistor, wherein a first end of the first transistor is used to receive the enable signal, a second end of the first transistor is connected to the input voltage end, and a third end of the first transistor is connected to the input ground end;

[0016] A second transistor, wherein the first end of the second transistor is connected to the second end of the first transistor, the second end of the second transistor is respectively connected to the input voltage end and the enable end of the control chip, and the third end of the second transistor is connected to the ground end of the control chip.

[0017] Optionally, the level conversion module further includes:

[0018] A first resistor, wherein a first end of the first resistor is used to receive the enable signal, and a second end of the first resistor is connected to a first end of the first transistor;

[0019] a second resistor, wherein a first end of the second resistor is connected to the input voltage end, and a second end of the second resistor is connected to the second end of the first transistor;

[0020] A third resistor, wherein a first end of the third resistor is connected to the input voltage end, and a second end of the third resistor is connected to the second end of the second transistor.

[0021] Optionally, the negative pressure circuit further includes:

[0022] A feedback module is connected to the input ground terminal, the second terminal of the second capacitor and the feedback terminal of the control chip respectively.

[0023] Optionally, the feedback module includes:

[0024] a fourth resistor, a first end of the fourth resistor being connected to the second end of the inductor;

[0025] A fifth resistor, wherein a first end of the fifth resistor is connected to the second end of the fourth resistor, and a second end of the fifth resistor is connected to the second end of the second capacitor.

[0026] Optionally, the negative pressure circuit further includes:

[0027] A third capacitor, wherein a first end of the third capacitor is connected to the guide end of the control chip, and a second end of the third capacitor is connected to the first end of the inductor.

[0028] Optionally, the negative pressure circuit further includes:

[0029] A fourth capacitor, wherein a first end of the fourth capacitor is connected to the input ground end, and a second end of the fourth capacitor is connected to the feedback end of the control chip.

[0030] In addition, to achieve the above-mentioned purpose, the present application provides a negative pressure module, which includes the negative pressure circuit as described above.

[0031] In addition, to achieve the above objectives, the present application provides a negative pressure device, which includes the negative pressure module as described above.

[0032] The present application provides a negative voltage circuit, which includes: a control chip, wherein the input end of the control chip is connected to the input voltage end; a first capacitor, wherein the first end of the first capacitor is connected to the input voltage end, and the second end of the first capacitor is connected to the input ground end; an inductor, wherein the first end of the inductor is connected to the control end of the control chip, the second end of the inductor is connected to the input ground end, and the second end of the inductor serves as a first output end; a diode, wherein the first end of the diode is connected to the first end of the inductor, and the second end of the diode is connected to the ground end of the control chip; and a second capacitor, wherein the first end of the second capacitor is connected to the second end of the inductor, the second end of the second capacitor is connected to the ground end of the control chip, and the second end of the first capacitor serves as a second output end.

[0033] Compared with the BUCK circuit of the traditional technology, the ground of the input capacitor, the ground of the output capacitor, and the ground of the chip are all shared, and all the potentials inside the chip are referenced to this ground. The present application realizes that the negative electrode of the input capacitor (i.e., the first capacitor) is still connected to the negative electrode of the input power supply, i.e., the earth, and the output end of the inductor is also connected to the earth and serves as the first output end. At the same time, the negative electrode of the output capacitor (i.e., the second capacitor) is short-circuited with the ground of the chip to form a new potential as the second output end. Thus, a negative voltage is formed through the first output end and the second output end, and a DC positive voltage generates a negative voltage. No negative voltage chip is required, which greatly reduces the cost of generating negative voltage in DCDC (direct current to direct current conversion). BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A schematic diagram of the structure of a negative voltage circuit provided in one embodiment of the present application;

[0035] Figure 2 A schematic diagram of the structure of a negative voltage circuit provided by another embodiment of the present application;

[0036] Figure 3 A detailed structural diagram of a level conversion module in a negative voltage circuit provided by another embodiment of the present application;

[0037] Figure 4 A schematic diagram of a negative voltage circuit structure provided in yet another embodiment of the present application;

[0038] Figure 5 A detailed structural schematic diagram of a negative voltage circuit provided in yet another embodiment of the present application.

[0039] Description of Figure Numbers:

[0040] Label name Label name U1 Control chip C1 First capacitor C2 Second capacitor D1 diode L1 inductance VSYS Input voltage terminal EGND Input ground 10 Level conversion module Q1 The first transistor Q2 The second transistor R1-R5 The first to fifth resistors 20 Feedback module C3 The third capacitor C4 The fourth capacitor

[0041] The purpose, features and advantages of this application will be further described in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0042] 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.

[0043] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0044] It should be noted that all directional indications in the embodiments of the present application (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0045] In this application, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0046] In addition, in this application, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0047] AR smart glasses are derived from augmented reality (AR) technology, which is a technology that can combine virtual information with the real world. With the improvement of the computing power of portable electronic products, the use of AR technology has become more and more extensive. The goal of this technology is to apply virtual information to the real world and superimpose computer-generated virtual objects, scenes or system prompts on real scenes, thereby enhancing reality.

[0048] Micro LED light machine is one of the display technologies. Micro LED is a technology that thins, miniaturizes and arrays LEDs. The components of the display array are LED light-emitting units with a size of 1 to 60μm. In the application of Micro LED light machine backlight negative pressure technology, it mainly involves the design and optimization of negative pressure control circuits. By reasonably designing the negative pressure control circuit, the brightness of the backlight source can be effectively adjusted, thereby achieving a more uniform lighting effect.

[0049] In traditional technology, the dedicated negative voltage DCDC (direct current to direct current conversion) is a chip model LMR70503, which directly generates negative voltage from positive voltage, thereby ensuring the power consumption and stability of the negative voltage control circuit, but the cost of the chip is very high.

[0050] Based on this, the present application proposes a negative voltage circuit, a negative voltage module and a negative voltage device, wherein the negative voltage circuit includes: a control chip, a first capacitor, an inductor, a diode, and a second capacitor. The present application realizes that the negative electrode of the input capacitor is still connected to the negative electrode of the input power supply, that is, the ground, and the output end of the inductor is also connected to the ground and serves as the first output end. At the same time, the negative electrode of the output capacitor and the ground of the chip are short-circuited to form a new potential as the second output end. Thus, a negative voltage is formed through the first output end and the second output end, thereby realizing the generation of negative voltage from DC positive voltage, without the need for a negative voltage chip, and greatly reducing the cost of generating negative voltage by DCDC (direct current to direct current conversion).

[0051] The present application provides a negative voltage circuit, referring to Figure 1, Figure 1 This is a schematic diagram of the structure of a negative voltage circuit provided in an embodiment of the present application, wherein the negative voltage circuit comprises:

[0052] A control chip U1, wherein the input terminal VIN of the control chip U1 is connected to the input voltage terminal VSYS; the control chip U1 may be a SGM61230XTN6G / TR chip;

[0053] a first capacitor C1, wherein a first end of the first capacitor C1 is connected to the input voltage terminal VSYS, and a second end of the first capacitor C1 is connected to the input ground terminal EGND; an inductor L1, wherein a first end of the inductor L1 is connected to the control terminal SW of the control chip U1, and a second end of the inductor L1 is connected to the input ground terminal EGND, and the second end of the inductor L1 serves as a first output terminal;

[0054] A diode D1, wherein a first end of the diode D1 is connected to a first end of the inductor L1, and a second end of the diode D1 is connected to a ground terminal GND of the control chip U1;

[0055] A second capacitor C2, wherein a first end of the second capacitor C2 is connected to the second end of the inductor L1, a second end of the second capacitor C2 is connected to the ground terminal GND of the control chip U1, and a second end of the second capacitor C2 serves as a second output terminal.

[0056] In this embodiment, the input voltage includes a DC power supply consisting of an input voltage terminal VSYS and an input ground terminal GND. After the voltage of the input voltage terminal VSYS is sent to the input terminal VIN of the control chip U1, the voltage that powers all logic devices inside the control chip U1 is output to the ground terminal of the control chip U1, forming a new potential VCOM, i.e., the second output terminal, and the input ground terminal EGND is used as the first output terminal, thereby outputting a negative voltage through the first output terminal and the second output terminal, breaking away from the traditional practice of all voltages using the input ground terminal EGND as a reference voltage.

[0057] It should be noted that this application is based on the BUCK (step-down) circuit, split into a BUCK-BOOST circuit and generates negative voltage, but it is different from the traditional BUCK-BOOST (step-down-boost) circuit. Since the output end of the inductor L1 is connected to the input ground end EGND, a negative voltage is output, which is suitable for negative voltage output scenarios, such as operational amplifiers or backlight circuits that require positive and negative voltage power supply in the system. If the output voltage between the first output end and the second output end is V0, the input voltage Vin and the output voltage VO need to be less than the maximum withstand voltage of the control end SW. In this negative voltage circuit, the voltage of the control terminal SW refers to the ground terminal GND of the control chip U1. If the withstand voltage of the control terminal SW is analyzed, it needs to be performed under the premise that the lower tube of the control chip U1 is turned off and the upper tube is turned on. The upper tube and the lower tube are switch tubes in the control chip U1. When the upper tube is turned on, the voltage of the control terminal SW relative to the ground is Vin-V0. Since V0 is a negative voltage, the voltage difference between the control terminal SW and the ground terminal GND of the control chip U1 is Vin+|V0|. Therefore, when performing negative voltage conversion, it is necessary to pay attention to the maximum input voltage, and at the same time, the maximum output voltage must be selected to determine whether the control chip U1 is reliable. Since the ground terminal GND of the control chip U1 is different from the input ground terminal EGND, when the control chip U1 is powered on, the input voltage Vin is output to the ground of the control chip U1 through the LDO that powers all logic devices inside the control chip U1, and then passes through the diode D1 and the inductor L1, and finally flows to the input ground terminal EGND. Therefore, the minimum input voltage applied to the input terminal VIN of the control chip U1 at this time needs to be higher than the sum of the undervoltage protection point UVLO of the control chip and the conduction voltage drop VD of the freewheeling diode.

[0058] The present application can generate negative voltage through a negative voltage circuit, and can be suitable for application scenarios such as power amplifier negative voltage circuit and backlight negative voltage circuit. In addition, the output voltage can be adjusted within a certain range, including positive voltage and negative voltage, so that the negative voltage circuit can adapt to the voltage requirements of more different devices, and by adjusting the on and off of the switch tube, it operates in different working modes, thereby improving the utilization and stability of the power supply.

[0059] Optionally, in some feasible embodiments, refer to Figure 2 , Figure 2 A schematic diagram of a negative voltage circuit provided in another embodiment of the present application, wherein the negative voltage circuit further comprises:

[0060] The level conversion module 10 is respectively connected to the input voltage terminal VSYS, the enable terminal EN of the control chip U1 and the ground terminal GND of the control chip U1, and is used for receiving an enable signal and sending it to the enable terminal EN of the control chip U1 after level conversion.

[0061] In this embodiment, since the ground of the MCU and the power ground are grounded, it is necessary to realize power supply to the enable terminal EN of the control chip U1 through the level conversion module 10. When the level conversion module 10 receives the enable signal sent by the MCU of the system, it performs level conversion and supplies power to the enable terminal EN of the control chip U1. When the level conversion module 10 receives a high level, it pulls down the enable terminal EN of the control chip U1, and when the level conversion module 10 receives a low level, it raises the enable terminal EN of the control chip U1, so that the enable signal sent by the MCU of the system matches the enable terminal EN of the control chip U1.

[0062] Optionally, in some feasible embodiments, refer to Figure 3 , Figure 3 This is a detailed structural diagram of a level conversion module in a negative voltage circuit provided in another embodiment of the present application, wherein the level conversion module 10 further includes:

[0063] The level conversion module includes: a first transistor Q1 and a second transistor Q2;

[0064] a first transistor Q1, wherein a first end of the first transistor Q1 is used to receive the enable signal, a second end of the first transistor Q1 is connected to the input voltage end VSYS, and a third end of the first transistor Q1 is connected to the input ground end EGND;

[0065] A second transistor Q2, wherein the first end of the second transistor Q2 is connected to the second end of the first transistor Q1, the second end of the second transistor Q2 is respectively connected to the input voltage end VSYS and the enable end EN of the control chip U1, and the third end of the second transistor Q2 is connected to the ground end GND of the control chip U1.

[0066] In this embodiment, when the MCU of the system has no signal output, the first end of the first transistor Q1 does not receive the enable signal, and the first transistor Q1 is not turned on. At this time, the voltage of the first end of the second transistor Q2 cannot be pulled down, that is, the voltage of the input voltage end VSYS is given to the first end of the second transistor Q2, so that the second transistor Q2 is turned on. When the second transistor Q2 is turned on, the second end voltage of the second transistor Q2 is pulled down through the ground end GND of the control chip U1, and then the enable end EN of the control chip U1 is pulled down, so that the enable signal received by the enable end EN of the control chip U1 is a low-level signal. When the MCU of the system has a signal output, the first end of the first transistor Q1 receives the enable signal, and the first transistor Q1 is turned on, thereby pulling down the first end voltage of the second transistor Q2 through the input ground end EGND, so that the second transistor Q2 is turned off. At this time, the voltage of the input voltage end VSYS is given to the enable end EN of the control chip U1, so that the enable signal received by the enable end EN of the control chip U1 is a high-level signal.

[0067] Optionally, in some feasible embodiments, refer to Figure 3 , the level conversion module 10 further includes:

[0068] A first resistor R1, wherein a first end of the first resistor R1 is used to receive the enable signal, and a second end of the first resistor R1 is connected to a first end of the first transistor Q1;

[0069] a second resistor R2, wherein a first end of the second resistor R2 is connected to the input voltage end VSYS, and a second end of the second resistor R2 is connected to the second end of the first transistor Q1;

[0070] A third resistor R3 , wherein a first end of the third resistor R3 is connected to the input voltage end VSYS, and a second end of the third resistor R3 is connected to the second end of the second transistor Q2 .

[0071] In this embodiment, the first resistor R1, the second resistor R2 and the third resistor R3 play a role in voltage regulation, so that when the MCU of the system sends an enable signal, the voltage for turning on the first transistor Q1 is reached, and when the MCU of the system does not send an enable signal, the first transistor Q1 cannot be turned on. When the first transistor Q1 is turned on, the voltage of the first end of the second transistor Q2 is pulled down by the second resistor R2, so that the second transistor cannot be turned on, and when the first transistor Q1 is not turned on, the turn-on voltage of the second transistor Q2 is reached. Through the third resistor R3, when the second transistor Q2 is not turned on, the voltage given to the enable terminal EN of the control chip U1 is a high level, and when the second transistor Q2 is turned on, the voltage given to the enable terminal EN of the control chip U1 is a low level.

[0072] Optionally, in some feasible embodiments, refer to Figure 4 , Figure 4 A schematic diagram of a negative voltage circuit structure provided in another embodiment of the present application, wherein the negative voltage circuit further comprises:

[0073] The feedback module 20 is connected to the input ground terminal EGND, the second end of the second capacitor C2 and the feedback terminal FB of the control chip U1 respectively.

[0074] In this embodiment, the feedback module 20 is respectively connected to the input ground terminal EGND and the second end of the second capacitor C2, collects the voltage between the first output terminal and the second output terminal, and sends the voltage to the feedback terminal FB of the control chip U1, thereby adjusting the output voltage of the control chip U1.

[0075] Optionally, in some feasible embodiments, refer to Figure 5 , Figure 5A detailed structural diagram of a negative pressure circuit provided in another embodiment of the present application, wherein the feedback module 20 includes:

[0076] a fourth resistor R4, wherein a first end of the fourth resistor R4 is connected to a second end of the inductor L1;

[0077] A fifth resistor R5, wherein a first end of the fifth resistor R5 is connected to a second end of the fourth resistor R4, and a second end of the fifth resistor R5 is connected to a second end of the second capacitor C2.

[0078] In this embodiment, the output voltage is sent to the feedback terminal FB of the control chip U1 through the fourth resistor R4 and the fifth resistor R5, so that the control chip U1 adjusts the output voltage based on the feedback voltage, thereby improving the accuracy of the output voltage.

[0079] Optionally, in some feasible embodiments, refer to Figure 5 , the negative voltage circuit further includes:

[0080] A third capacitor C3 , wherein a first end of the third capacitor C3 is connected to the boot terminal BOOT of the control chip U1 , and a second end of the third capacitor C3 is connected to the first end of the inductor L1 .

[0081] In this embodiment, the third capacitor C3 plays the role of a voltage-changing capacitor, plays the role of driving the high-voltage side and internal regulation of the control chip U1 , and plays the role of guiding the control terminal SW of the control chip U1 .

[0082] Optionally, in some feasible embodiments, refer to Figure 5 , the negative voltage circuit further includes:

[0083] A fourth capacitor C4, a first end of the fourth capacitor C4 is connected to the input ground end EGND, and a second end of the fourth capacitor C4 is connected to the feedback end FB of the control chip U1.

[0084] In this embodiment, the fourth capacitor C4 serves to improve the transient response of the load.

[0085] The present application also proposes a negative pressure module, which includes a negative pressure circuit. The specific structure of the negative pressure module refers to the above-mentioned embodiment. Since the optimized negative pressure module adopts all the technical solutions of all the above-mentioned embodiments, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be repeated here one by one.

[0086] The present application also proposes a negative pressure device, which includes a negative pressure circuit. The specific structure of the negative pressure circuit in the negative pressure device refers to the above-mentioned embodiment. Since the negative pressure device adopts all the technical solutions of all the above-mentioned embodiments, it at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here.

[0087] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or system. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or system including the element.

[0088] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0089] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a computer storage medium (such as Flash memory, ROM / RAM, disk, CD), and includes several instructions for enabling a controller in a terminal device (which can be a mobile phone, computer, server, or network device, etc.) to control the storage medium to perform data read and write operations to execute the methods described in each embodiment of the present application.

[0090] The above are only preferred embodiments of the present application, and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A negative voltage circuit, characterized in that: The negative pressure circuit comprises: A control chip, wherein an input terminal of the control chip is connected to an input voltage terminal; A first capacitor, wherein a first end of the first capacitor is connected to the input voltage end, and a second end of the first capacitor is connected to the input ground end; an inductor, wherein a first end of the inductor is connected to a control end of the control chip, a second end of the inductor is connected to an input ground end, and the second end of the inductor serves as a first output end; a diode, wherein a first end of the diode is connected to a first end of the inductor, and a second end of the diode is connected to a ground terminal of the control chip; A second capacitor, wherein a first end of the second capacitor is connected to the second end of the inductor, a second end of the second capacitor is connected to the ground end of the control chip, and the second end of the second capacitor serves as a second output end.

2. The negative voltage circuit according to claim 1, characterized in that: The negative pressure circuit also includes: A level conversion module is connected to the input voltage terminal and the enable terminal of the control chip respectively, and is used for receiving an enable signal and sending the signal to the enable terminal of the control chip after performing level conversion.

3. The negative voltage circuit according to claim 2, characterized in that: The level conversion module comprises: A first transistor, wherein a first end of the first transistor is used to receive the enable signal, a second end of the first transistor is connected to the input voltage end, and a third end of the first transistor is connected to the input ground end; A second transistor, wherein the first end of the second transistor is connected to the second end of the first transistor, the second end of the second transistor is respectively connected to the input voltage end and the enable end of the control chip, and the third end of the second transistor is connected to the ground end of the control chip.

4. The negative voltage circuit according to claim 3, characterized in that: The level conversion module also includes: A first resistor, wherein a first end of the first resistor is used to receive the enable signal, and a second end of the first resistor is connected to a first end of the first transistor; a second resistor, wherein a first end of the second resistor is connected to the input voltage end, and a second end of the second resistor is connected to the second end of the first transistor; A third resistor, wherein a first end of the third resistor is connected to the input voltage end, and a second end of the third resistor is connected to the second end of the second transistor.

5. The negative voltage circuit according to claim 4, characterized in that: The negative pressure circuit also includes: A feedback module is connected to the input ground terminal, the second terminal of the second capacitor and the feedback terminal of the control chip respectively.

6. The negative voltage circuit according to claim 5, characterized in that: The feedback module comprises: a fourth resistor, a first end of the fourth resistor being connected to the second end of the inductor; A fifth resistor, wherein a first end of the fifth resistor is connected to the second end of the fourth resistor, and a second end of the fifth resistor is connected to the second end of the second capacitor.

7. The negative voltage circuit according to claim 6, characterized in that: The negative pressure circuit also includes: A third capacitor, wherein a first end of the third capacitor is connected to the guide end of the control chip, and a second end of the third capacitor is connected to the first end of the inductor.

8. The negative voltage circuit according to claim 7, characterized in that: The negative pressure circuit also includes: A fourth capacitor, wherein a first end of the fourth capacitor is connected to the input ground end, and a second end of the fourth capacitor is connected to the feedback end of the control chip.

9. A negative pressure module, characterized in that: The negative pressure module comprises the negative pressure circuit as described in any one of claims 1 to 8.

10. A negative pressure device, characterized in that: The negative pressure device comprises the negative pressure module as claimed in claim 9.

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