Negative voltage generating circuit and device

Abstract

The utility model relates to the technical field of electronic circuits, and discloses a negative voltage generation circuit and device, a switch control circuit of the circuit is respectively connected with an input power supply and a PWM output device, an energy storage circuit is respectively connected with the switch control circuit and a voltage reversal circuit, and the switch control circuit is connected with the PWM output device; when the switch control circuit receives a high-level trigger signal output by the PWM output equipment, the connection between the input power supply and the energy storage circuit is conducted, so that the input power supply stores energy for the energy storage circuit; when the switch control circuit receives a low-level trigger signal output by the PWM output device, the energy storage circuit and the voltage inversion circuit are connected. When the voltage inversion circuit is connected and conducted with the energy storage circuit, the energy storage voltage output after energy storage of the energy storage circuit is received, the energy storage voltage is converted into the corresponding negative energy storage voltage, a DC-DC chip does not need to be additionally arranged, the circuit is effectively simplified, and the cost is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of electronic circuits, and in particular to a negative pressure generating circuit and a device. Background Art

[0002] At present, negative voltage power supply is used in some electronic products, such as the dual power supply method of operational amplifiers. The existing method is to set a DC-DC chip that can output negative voltage in the electronic product, and use the DC-DC chip to generate negative voltage to power the electronic product. However, under this method, an additional DC-DC chip needs to be set on the basis of the original circuit, which makes the circuit design complicated and the cost high.

[0003] The above contents are only used to assist in understanding the technical solution of the present utility model and do not constitute an admission that the above contents are prior art. Utility Model Content

[0004] The main purpose of the utility model is to provide a negative voltage generating circuit and device, aiming to solve the technical problem that the prior art needs to additionally set a DC-DC chip on the basis of the original circuit, resulting in complex circuit design and high cost.

[0005] To achieve the above object, the utility model provides a negative voltage generating circuit, the circuit comprising a switch control circuit, an energy storage circuit and a voltage reversal circuit;

[0006] The switch control circuit is connected to the input power supply and the PWM output device respectively, and the energy storage circuit is connected to the switch control circuit and the voltage inversion circuit respectively;

[0007] The switch control circuit is used to conduct the connection between the input power supply and the energy storage circuit when receiving the high-level trigger signal output by the PWM output device, so that the input power supply stores energy for the energy storage circuit;

[0008] The switch control circuit is further used to conduct the connection between the energy storage circuit and the voltage inversion circuit when receiving a low-level trigger signal output by the PWM output device;

[0009] The voltage inversion circuit is used to receive the energy storage voltage output by the energy storage circuit after energy storage when connected to the energy storage circuit and turned on, and convert the energy storage voltage into a corresponding negative energy storage voltage.

[0010] Optionally, the switch control circuit includes a first switch module and a second switch module;

[0011] The second switch module is connected to the first switch module, the input power supply and the energy storage circuit respectively, and the first switch module is connected to the PWM output device;

[0012] The first switch module is used to ground the control end of the second switch module when receiving the high-level trigger signal output by the PWM output device, so that the low-level driving signal is input to the control end of the second switch module;

[0013] The second switch module is used to conduct the connection between the input power supply and the energy storage circuit when receiving the low-level driving signal, so that the input power supply stores energy for the energy storage circuit.

[0014] Optionally, the first switch module is further configured to connect the input power supply to the control end of the second switch module when receiving the low level trigger signal output by the PWM output device, so that the input power supply outputs a power drive signal to the control end of the second switch module;

[0015] The second switch module is used to disconnect the energy storage circuit from the input power supply and connect the energy storage circuit to the voltage inversion circuit when receiving the power drive signal.

[0016] Optionally, the first switch module includes a first transistor;

[0017] The base of the first transistor is connected to the PWM output device, the emitter of the first transistor is grounded, and the collector of the first transistor is connected to the second switch module.

[0018] Optionally, the second switch module includes a first MOS tube;

[0019] The gate of the first MOS tube is respectively connected to the input power supply and the collector of the first transistor, the source of the first MOS tube is connected to the input power supply, and the drain of the first MOS tube is connected to the energy storage circuit.

[0020] Optionally, the energy storage circuit includes a first capacitor and a first diode;

[0021] The first end of the first capacitor is connected to the drain of the first MOS tube, the second end of the first capacitor is respectively connected to the anode of the first diode and the voltage inversion circuit, and the cathode of the first diode is grounded.

[0022] Optionally, the voltage inversion circuit includes a second capacitor, a second diode and a first resistor;

[0023] The first end of the second capacitor is connected to the anode of the second diode, the cathode of the second diode is respectively connected to the second end of the first capacitor and the anode of the first diode, the second end of the second capacitor and the first end of the first resistor are both grounded, and the second end of the first resistor is respectively connected to the drain of the first MOS tube and the first end of the first capacitor.

[0024] Optionally, the circuit further includes a first voltage divider circuit and a second voltage divider circuit;

[0025] The first voltage-dividing circuit is respectively connected to the PWM output device, the base of the first transistor and the emitter of the first transistor, and the second voltage-dividing circuit is respectively connected to the input power supply, the source of the first MOS transistor, the gate of the first MOS transistor and the collector of the first transistor;

[0026] The first voltage divider circuit is used for dividing the voltage of the PWM signal when the PWM signal output by the PWM output device is at a high level, and outputting the high level trigger signal to the base of the first transistor;

[0027] The first voltage divider circuit is further used for dividing the voltage of the PWM signal when the PWM signal output by the PWM output device is at a low level, and outputting the low-level trigger signal to the base of the first transistor;

[0028] The second voltage divider circuit is used to divide the power supply voltage output by the input power supply when the input power supply is connected to the energy storage circuit, so that the input power supply stores energy for the energy storage circuit through the divided power supply voltage.

[0029] Optionally, the first voltage divider circuit includes a second resistor and a third resistor; the second voltage divider circuit includes a fourth resistor and a fifth resistor;

[0030] The first end of the second resistor is connected to the PWM output device, the second end of the second resistor is respectively connected to the base of the first transistor and the first end of the third resistor, and the second end of the third resistor is grounded;

[0031] The first end of the fourth resistor is connected to the input power supply and the source of the first MOS tube respectively, the second end of the fourth resistor is connected to the gate of the first MOS tube and the first end of the fifth resistor respectively, and the second end of the fifth resistor is connected to the collector of the first transistor.

[0032] In addition, to achieve the above-mentioned purpose, the present invention also provides a negative pressure generating device, which includes the negative pressure generating circuit as described above.

[0033] The utility model provides a negative voltage generating circuit and device, the circuit includes a switch control circuit, an energy storage circuit and a voltage reversal circuit; the switch control circuit is respectively connected to an input power supply and a PWM output device, and the energy storage circuit is respectively connected to the switch control circuit and the voltage reversal circuit; when the switch control circuit of the utility model receives a high-level trigger signal output by the PWM output device, the connection between the input power supply and the energy storage circuit is turned on, so that the input power supply stores energy for the energy storage circuit; when the switch control circuit receives a low-level trigger signal output by the PWM output device, the connection between the energy storage circuit and the voltage reversal circuit is turned on; when the voltage reversal circuit is connected to the energy storage circuit and turned on, the energy storage voltage output by the energy storage circuit after energy storage is received, and the energy storage voltage is converted into a corresponding negative energy storage voltage. The utility model stores energy for the energy storage circuit through the input power supply, and when the voltage reversal circuit is connected to the energy storage circuit and turned on, the voltage reversal circuit converts the energy storage voltage output by the energy storage circuit after energy storage is converted into a corresponding negative energy storage voltage, without the need to set up an additional DC-DC chip, effectively simplifying the circuit and reducing the cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a structural schematic diagram of the first embodiment of the negative pressure generating circuit of the utility model;

[0035] Figure 2 It is a structural schematic diagram of the second embodiment of the negative pressure generating circuit of the utility model;

[0036] Figure 3 This is a circuit schematic diagram of a second embodiment of the negative pressure generating circuit of the utility model;

[0037] Figure 4 It is a structural schematic diagram of the third embodiment of the negative pressure generating circuit of the utility model;

[0038] Figure 5 This is a circuit schematic diagram of the third embodiment of the negative pressure generating circuit of the present utility model.

[0039] Description of Figure Numbers:

[0040] Label name Label name Q1 The first transistor Q2 The first MOS tube C1 First capacitor C2 Second capacitor D1 The first diode D2 The second diode R1 First resistor R2 Second resistor R3 The third resistor R4 The fourth resistor R5 Fifth resistor VIN Input Power VOUT Output voltage

[0041] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with 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 invention, and are not used to limit the present invention.

[0043] The technical solution of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0044] It should be noted that the descriptions of "first", "second", etc. in the embodiments of the present utility model are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. 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 the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.

[0045] Reference Figure 1 , Figure 1 It is a structural schematic diagram of the first embodiment of the negative pressure generating circuit of the utility model.

[0046] like Figure 1 As shown, in this embodiment, the negative voltage generating circuit includes a switch control circuit 100 , a storage circuit 200 and a voltage reversal circuit 300 .

[0047] The switch control circuit 100 is connected to the input power source VIN and the PWM output device 400 respectively, and the energy storage circuit 200 is connected to the switch control circuit 100 and the voltage inversion circuit 300 respectively.

[0048] The switch control circuit 100 is used to connect the input power source VIN to the energy storage circuit 200 when receiving a high level trigger signal output by the PWM output device 400 , so that the input power source VIN stores energy for the energy storage circuit 200 .

[0049] It should be noted that the PWM output device 400 may be a device that outputs a PWM signal, such as a system on chip (SOC) or a single-chip microcomputer (MCU).

[0050] It is understandable that the above-mentioned high-level trigger signal can be a PWM signal whose voltage reaches a preset threshold, wherein the preset threshold can be set based on actual needs. For example, when the voltage of the input power supply VIN is 12V, the above-mentioned preset threshold can be 3.5V, and the voltage of the above-mentioned high-level trigger signal can also be 3.5V.

[0051] In a specific implementation, the above-mentioned switch control circuit 100 can be equivalent to a switch device controlled by a PWM signal. The switch control circuit 100 is closed when receiving a high-level trigger signal output by the PWM output device 400, and the connection between the input power supply VIN and the energy storage circuit 200 is turned on. The input power supply VIN is connected to the energy storage circuit 200 to form a charging circuit with the energy storage circuit 200. The input power supply VIN can store energy for the energy storage circuit 200 based on the charging circuit.

[0052] The switch control circuit 100 is further configured to connect the energy storage circuit 200 to the voltage inversion circuit 300 when receiving a low level trigger signal output by the PWM output device 400 .

[0053] It should be noted that the low-level trigger signal may be a PWM signal whose voltage is lower than a preset threshold, wherein, for example, the preset threshold may be 3.5V, and the voltage of the low-level trigger signal may also be 0V.

[0054] In a specific implementation, the switch control circuit 100 is disconnected when receiving a low-level trigger signal output by the PWM output device 400, disconnecting the connection between the input power supply VIN and the energy storage circuit 200, so that the connection between the energy storage circuit 200 that has stored electrical energy and the voltage reversal circuit 300 is turned on. If the energy storage circuit 200 is fully charged, the energy storage voltage of the energy storage circuit 200 is the power supply voltage of the input power supply VIN. After the energy storage circuit 200 stores electrical energy and is disconnected from the input power supply VIN, it can be connected to the voltage reversal circuit 300 for discharge, that is, the energy storage circuit 200 is equivalent to a power supply to supply power to the voltage reversal circuit 300.

[0055] The voltage inversion circuit 300 is used to receive the energy storage voltage output by the energy storage circuit 200 after energy storage when connected to the energy storage circuit 200 and turned on, and convert the energy storage voltage into a corresponding negative energy storage voltage.

[0056] In a specific implementation, after the voltage reversal circuit 300 is connected to the energy storage circuit 200 and turned on, it receives the energy storage voltage output by the energy storage circuit 200 after energy storage. When the voltage reversal circuit 300 is fully charged, the potential difference between the input and output ends of the voltage reversal circuit 300 is the energy storage voltage. The input end of the voltage reversal circuit 300 is consistent with the high potential of the energy storage circuit 200. At this time, the high potential of the energy storage circuit 200 is grounded, that is, the potential of the input end of the voltage reversal circuit 300 is 0V. Since the potential difference is the energy storage voltage, the output end of the voltage reversal circuit 300 will generate a negative energy storage voltage, that is, the output voltage VOUT of the voltage reversal circuit 300 is a negative energy storage voltage, so as to ensure that the potential difference is the energy storage voltage, and the energy storage voltage can be converted into a corresponding negative energy storage voltage without a DC-DC chip.

[0057] For example, when the voltage obtained by storing energy in the energy storage circuit 200 is 12V, the voltage reversal circuit 300 can receive the energy stored in the energy storage circuit 200. When the energy storage is completed, the potential difference between the input and output ends of the voltage reversal circuit 300 is 12V. When the input end of the voltage reversal circuit 300 is grounded, that is, the input end is 0V, in order to achieve a potential difference of 12V, the output end of the voltage reversal circuit 300 will output an output voltage VOUT of -12V, thereby realizing the conversion of the energy storage voltage into the corresponding negative energy storage voltage.

[0058] The negative voltage generating circuit of this embodiment includes a switch control circuit, an energy storage circuit and a voltage reversal circuit; the energy storage circuit is connected to the input power supply, the switch control circuit and the voltage reversal circuit respectively, and the switch control circuit is connected to the PWM output device; when the switch control circuit of this embodiment receives a high-level trigger signal output by the PWM output device, it conducts the connection between the input power supply and the energy storage circuit so that the input power supply stores energy for the energy storage circuit; when the switch control circuit receives a low-level trigger signal output by the PWM output device, it conducts the connection between the energy storage circuit and the voltage reversal circuit; when the voltage reversal circuit is connected to the energy storage circuit and is turned on, it receives the energy storage voltage output by the energy storage circuit after energy storage, and converts the energy storage voltage into a corresponding negative energy storage voltage. In this embodiment, the input power supply is used to store energy for the energy storage circuit, and when the voltage reversal circuit is connected to the energy storage circuit and is turned on, the voltage reversal circuit converts the energy storage voltage output by the energy storage circuit after energy storage into a corresponding negative energy storage voltage, and no additional DC-DC chip is required, which effectively simplifies the circuit and reduces the cost.

[0059] refer to Figure 2 , Figure 2 It is a structural schematic diagram of the second embodiment of the negative pressure generating circuit of the utility model.

[0060] Based on the above first embodiment, in this embodiment, the switch control circuit 100 includes a first switch module 101 and a second switch module 102 .

[0061] The second switch module 102 is connected to the first switch module 101 , the input power source VIN and the energy storage circuit 200 respectively, and the first switch module 101 is connected to the PWM output device 400 .

[0062] The first switch module 101 is used to ground the control end of the second switch module 102 when receiving the high-level trigger signal output by the PWM output device 400 , so that a low-level driving signal is input to the control end of the second switch module 102 .

[0063] It should be noted that the control end of the second switch module 102 is connected to the first switch module 101 , so that the first switch module 101 can output a corresponding driving signal to control the conduction state of the second switch module 102 .

[0064] For ease of understanding, refer to Figure 3 This is for illustration only, but does not limit this solution. Figure 3 1 is a circuit diagram of the second embodiment of the negative voltage generating circuit of the utility model. In this embodiment, the first switch module 101 includes a first transistor Q1.

[0065] The base of the first transistor Q1 is connected to the PWM output device 400 , the emitter of the first transistor Q1 is grounded, and the collector of the first transistor Q1 is connected to the second switch module 102 .

[0066] The second switch module 102 includes a first MOS transistor Q2.

[0067] The gate of the first MOS transistor Q2 is connected to the input power source VIN and the collector of the first transistor Q2 respectively, the source of the first MOS transistor Q2 is connected to the input power source VIN, and the drain of the first MOS transistor Q2 is connected to the energy storage circuit 200 .

[0068] In a specific implementation, the first transistor Q1 may be a PNP transistor, the first MOS transistor Q2 may be a PMOS transistor, and the PWM output device 400 may output a high-level trigger signal to the base of the first transistor Q1, turn on the first transistor Q1, and ground the gate of the first MOS transistor Q2 (i.e., the control end of the second switch module 102), so that a low-level driving signal is input to the gate of the first MOS transistor Q2.

[0069] The second switch module 102 is used to conduct the connection between the input power source VIN and the energy storage circuit 200 when receiving the low-level driving signal, so that the input power source VIN stores energy for the energy storage circuit 200 .

[0070] In a specific implementation, the gate of the first MOS tube Q2 is grounded, that is, it is closed when receiving a low-level driving signal, and the input power supply VIN is connected to the energy storage circuit 200, and the charging loop between the input power supply VIN and the energy storage circuit 200 is turned on, so that the input power supply VIN stores energy for the energy storage circuit.

[0071] like Figure 3 As shown, in this embodiment, the energy storage circuit 200 includes a first capacitor C1 and a first diode D1.

[0072] The first end of the first capacitor C1 is connected to the drain of the first MOS transistor Q2 , the second end of the first capacitor C1 is connected to the anode of the first diode D1 and the voltage inversion circuit 300 , respectively, and the cathode of the first diode D1 is grounded.

[0073] It should be noted that when the first MOS tube Q2 is closed, the input power supply VIN is connected to the first capacitor C1, and the charging circuit composed of the input power supply VIN, the first capacitor C1 and the first diode D1 is turned on. The input power supply VIN charges the first capacitor C1 through the charging circuit, and the current direction of the charging circuit flows from the anode of the first diode D1 to the cathode of the first diode D1.

[0074] Furthermore, in this embodiment, the first switch module 101 is also used to connect the input power supply VIN to the control end of the second switch module 102 when receiving the low-level trigger signal output by the PWM output device 400, so that the input power supply VIN outputs a power drive signal to the control end of the second switch module 102.

[0075] It should be noted that the power driving signal may be a high-level signal in which the voltage output by the input power source VIN is the power source voltage.

[0076] In the specific implementation, refer to Figure 3 When the gate of the first transistor Q1 does not receive the low-level trigger signal output by the PWM output device 400, the gate of the first transistor Q1 receives the power driving signal output by the input power source VIN and is disconnected, thereby disconnecting the input power source VIN from the first capacitor C1.

[0077] The second switch module 102 is used to disconnect the energy storage circuit 200 from the input power source VIN and connect the energy storage circuit 200 to the voltage inversion circuit 300 when receiving the power driving signal.

[0078] like Figure 3As shown, in this embodiment, the voltage inversion circuit 300 includes a second capacitor C2, a second diode D2 and a first resistor R1.

[0079] The first end of the second capacitor C2 is connected to the anode of the second diode D2, the cathode of the second diode D2 is respectively connected to the second end of the first capacitor C1 and the anode of the first diode D1, the second end of the second capacitor C2 and the first end of the first resistor R1 are both grounded, and the second end of the first resistor R1 is respectively connected to the drain of the first MOS tube Q2 and the first end of the first capacitor C1.

[0080] In the specific implementation, Figure 3 As shown, the gate of the first MOS tube Q1 is disconnected after receiving the power drive signal, so that the connection between the first capacitor C1 and the input power supply VIN is disconnected. At this time, the first capacitor C1 forms a path with the first resistor R1, the second capacitor C1 and the second diode D2. The first capacitor C1 discharges the stored energy storage voltage through the path, and charges the second capacitor C2 based on the energy storage voltage. The second capacitor C2 can charge the energy of the energy storage voltage, and the potential difference between the positive and negative electrodes of the second capacitor C2 is the energy storage voltage. Since the first end of the first capacitor C1 is grounded through the first resistor R1, the potential of the first end of the first capacitor C1 is pulled down, and the positive electrode of the second capacitor C2 is also grounded. In order to make the potential difference between the positive and negative electrodes of the second capacitor C2 the energy storage voltage, the negative electrode of the second capacitor C2 will generate a negative energy storage voltage, that is, the output voltage VOUT of the second capacitor C2 outputs a negative energy storage voltage, thereby achieving accurate voltage reversal and generating a stable negative voltage.

[0081] refer to Figure 4 , Figure 4 It is a structural schematic diagram of the third embodiment of the negative pressure generating circuit of the utility model.

[0082] Based on the above second embodiment, in this embodiment, the negative voltage generating circuit further includes a first voltage dividing circuit 501 and a second voltage dividing circuit 502 .

[0083] The first voltage divider circuit 501 is respectively connected to the PWM output device 400, the base of the first transistor Q1 and the emitter of the first transistor Q1, and the second voltage divider circuit 502 is respectively connected to the input power supply VIN, the source of the first MOS transistor Q2, the gate of the first MOS transistor Q2 and the collector of the first transistor Q1.

[0084] The first voltage divider circuit 501 is used to divide the voltage of the PWM signal when the PWM signal output by the PWM output device 400 is at a high level, and output the high level trigger signal to the base of the first transistor Q1.

[0085] In a specific implementation, in order to prevent the PWM output device 400 or the input power source VIN from damaging the device due to voltage mismatch or excessive voltage output, the first voltage divider circuit 501 and the second voltage divider circuit 502 may be provided.

[0086] like Figure 5 As shown, Figure 5 1 is a circuit diagram of the third embodiment of the negative voltage generating circuit of the present invention. In this embodiment, the first voltage dividing circuit 501 includes a second resistor R2 and a third resistor R3.

[0087] The second voltage divider circuit 502 includes a fourth resistor R4 and a fifth resistor R5.

[0088] The first end of the second resistor R2 is connected to the PWM output device 400 , the second end of the second resistor R2 is respectively connected to the base of the first transistor Q1 and the first end of the third resistor R3 , and the second end of the third resistor R3 is grounded.

[0089] The first end of the fourth resistor R4 is connected to the input power supply VIN and the source of the first MOS transistor Q2 respectively, the second end of the fourth resistor R4 is connected to the gate of the first MOS transistor Q2 and the first end of the fifth resistor R5 respectively, and the second end of the fifth resistor R5 is connected to the collector of the first transistor Q1.

[0090] It should be noted that when the PWM signal output by the PWM output device 400 is at a high level, the second resistor R2 and the third resistor R3 can divide the voltage of the high-level PWM signal to obtain the above-mentioned high-level trigger signal, and then output the high-level trigger signal obtained by the voltage division to the base of the first transistor Q1, thereby avoiding damage to the first transistor Q1 caused by voltage mismatch or excessive voltage of the PWM signal output by the PWM output device 400, thereby improving circuit stability.

[0091] The first voltage divider circuit 502 is further used to divide the voltage of the PWM signal when the PWM signal output by the PWM output device 400 is at a low level, and output the low level trigger signal to the base of the first transistor Q1.

[0092] In a specific implementation, when the PWM signal output by the PWM output device 400 is at a low level, the second resistor R2 and the third resistor R3 may also divide the voltage of the low-level PWM signal to obtain the above-mentioned high-level trigger signal, and then output the high-level trigger signal obtained by the voltage division to the base of the first transistor Q1, so that the voltage of the PWM signal output by the PWM output device 400 is low enough to avoid damage to the first transistor Q1 and improve circuit stability.

[0093] The second voltage divider circuit 502 is used to divide the power supply voltage output by the input power supply 400 when the input power supply VIN is connected to the energy storage circuit 200, so that the input power supply VIN stores energy for the energy storage circuit 200 through the divided power supply voltage.

[0094] In the specific implementation, Figure 5 As shown, when the first MOS tube Q2 is turned on and the input power supply VIN is connected to the first capacitor C1, the fourth resistor R4 and the fifth resistor R5 can divide the power supply voltage output by the input power supply VIN, so that the input power supply VIN stores energy for the first capacitor C1 through the divided power supply voltage, so as to avoid damage to the first capacitor C1 caused by mismatch of the power supply voltage output by the input power supply VIN or excessive power supply voltage, thereby improving circuit stability.

[0095] In addition, an embodiment of the present utility model further provides a negative pressure generating device, which includes the negative pressure generating circuit described above.

[0096] Other embodiments or specific implementations of the negative pressure generating device of the present invention may refer to the above-mentioned negative pressure generating circuit embodiment, which will not be described in detail here.

[0097] 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.

[0098] The serial numbers of the above-mentioned embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0099] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A negative voltage generating circuit, characterized in that: The circuit includes a switch control circuit, an energy storage circuit and a voltage reversal circuit; The switch control circuit is connected to the input power supply and the PWM output device respectively, and the energy storage circuit is connected to the switch control circuit and the voltage inversion circuit respectively; The switch control circuit is used to conduct the connection between the input power supply and the energy storage circuit when receiving the high-level trigger signal output by the PWM output device, so that the input power supply stores energy for the energy storage circuit; The switch control circuit is further used to conduct the connection between the energy storage circuit and the voltage inversion circuit when receiving a low-level trigger signal output by the PWM output device; The voltage inversion circuit is used to receive the energy storage voltage output by the energy storage circuit after energy storage when connected to the energy storage circuit and turned on, and convert the energy storage voltage into a corresponding negative energy storage voltage.

2. The negative voltage generating circuit according to claim 1, characterized in that: The switch control circuit includes a first switch module and a second switch module; The second switch module is connected to the first switch module, the input power supply and the energy storage circuit respectively, and the first switch module is connected to the PWM output device; The first switch module is used to ground the control end of the second switch module when receiving the high-level trigger signal output by the PWM output device, so that the low-level driving signal is input to the control end of the second switch module; The second switch module is used to conduct the connection between the input power supply and the energy storage circuit when receiving the low-level driving signal, so that the input power supply stores energy for the energy storage circuit.

3. The negative voltage generating circuit according to claim 2, characterized in that: The first switch module is further configured to connect the input power supply to the control end of the second switch module when receiving the low level trigger signal output by the PWM output device, so that the input power supply outputs a power drive signal to the control end of the second switch module; The second switch module is used to disconnect the energy storage circuit from the input power supply and connect the energy storage circuit to the voltage inversion circuit when receiving the power drive signal.

4. The negative voltage generating circuit according to claim 3, characterized in that: The first switch module includes a first transistor; The base of the first transistor is connected to the PWM output device, the emitter of the first transistor is grounded, and the collector of the first transistor is connected to the second switch module.

5. The negative voltage generating circuit according to claim 4, characterized in that: The second switch module includes a first MOS tube; The gate of the first MOS tube is connected to the input power supply and the collector of the first transistor respectively, the source of the first MOS tube is connected to the input power supply, and the drain of the first MOS tube is connected to the energy storage circuit.

6. The negative voltage generating circuit according to claim 5, characterized in that: The energy storage circuit includes a first capacitor and a first diode; The first end of the first capacitor is connected to the drain of the first MOS tube, the second end of the first capacitor is respectively connected to the anode of the first diode and the voltage inversion circuit, and the cathode of the first diode is grounded.

7. The negative voltage generating circuit according to claim 6, characterized in that: The voltage inversion circuit includes a second capacitor, a second diode and a first resistor; The first end of the second capacitor is connected to the anode of the second diode, the cathode of the second diode is respectively connected to the second end of the first capacitor and the anode of the first diode, the second end of the second capacitor and the first end of the first resistor are both grounded, and the second end of the first resistor is respectively connected to the drain of the first MOS tube and the first end of the first capacitor.

8. The negative voltage generating circuit according to any one of claims 5 to 7, characterized in that: The circuit also includes a first voltage divider circuit and a second voltage divider circuit; The first voltage-dividing circuit is respectively connected to the PWM output device, the base of the first transistor and the emitter of the first transistor, and the second voltage-dividing circuit is respectively connected to the input power supply, the source of the first MOS transistor, the gate of the first MOS transistor and the collector of the first transistor; The first voltage divider circuit is used for dividing the voltage of the PWM signal when the PWM signal output by the PWM output device is at a high level, and outputting the high level trigger signal to the base of the first transistor; The first voltage divider circuit is further used for dividing the voltage of the PWM signal when the PWM signal output by the PWM output device is at a low level, and outputting the low-level trigger signal to the base of the first transistor; The second voltage divider circuit is used to divide the power supply voltage output by the input power supply when the input power supply is connected to the energy storage circuit, so that the input power supply stores energy for the energy storage circuit through the divided power supply voltage.

9. The negative voltage generating circuit according to claim 8, characterized in that: The first voltage divider circuit includes a second resistor and a third resistor; The second voltage divider circuit includes a fourth resistor and a fifth resistor; The first end of the second resistor is connected to the PWM output device, the second end of the second resistor is respectively connected to the base of the first transistor and the first end of the third resistor, and the second end of the third resistor is grounded; The first end of the fourth resistor is connected to the input power supply and the source of the first MOS tube respectively, the second end of the fourth resistor is connected to the gate of the first MOS tube and the first end of the fifth resistor respectively, and the second end of the fifth resistor is connected to the collector of the first transistor.

10. A negative pressure generating device, characterized in that: The device comprises the negative pressure generating circuit according to any one of claims 1 to 9.

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