Negative pressure detection circuit for negative pressure wound therapy

Abstract

The utility model relates to the technical field of negative pressure wound therapy, and provides a negative pressure detection circuit for negative pressure wound therapy, which comprises a power supply circuit and a master control MCU (Microprogrammed Control Unit) circuit which are connected with each other, and is characterized in that a voltage acquisition circuit is connected between the power supply circuit and the master control MCU circuit; the main control MCU circuit is connected with a negative pressure sensor circuit and a negative pressure pump circuit, the power supply circuit comprises an on-off and protection circuit, a front filter circuit and a rear filter circuit, and the main control MCU circuit comprises a crystal oscillator circuit, a reset circuit and a filter circuit. Negative pressure value monitoring is carried out through an amplification circuit structure in the negative pressure sensor circuit, the monitored negative pressure value is processed through the main control MCU circuit, so that the negative pressure pump circuit is controlled, negative pressure value adjustment is carried out through cooperation of a motor driving circuit structure and an amplifier circuit structure in the negative pressure pump circuit, accurate monitoring and accurate adjustment of the negative pressure value are achieved, and the negative pressure pump circuit is controlled. And the whole circuit is simple in structure, low in production and assembly cost, and suitable for mass production.

Description

Technical Field

[0001] The utility model relates to the technical field of negative pressure wound treatment, in particular to a negative pressure detection circuit for negative pressure wound treatment. Background Art

[0002] In a negative pressure wound treatment (NPWT) system, the negative pressure value at the wound is mainly reflected by monitoring the negative pressure value in the pipeline. Accurately monitoring the negative pressure value in negative pressure wound treatment is an important guarantee for accelerating the wound healing of patients. Accurately monitoring the negative pressure value can greatly improve the comfort of patients during the wound healing process.

[0003] The existing negative pressure wound treatment system mainly detects the magnitude of the negative pressure value in the pipeline through a negative pressure sensor. However, the pressure value cannot be adjusted and can only work at a single pressure value, resulting in inaccurate monitoring and a large error range. It cannot adjust the negative pressure value according to the patient's own situation and cannot be adjusted with the negative pressure value most suitable for the patient's wound healing during the patient's recovery process. Although there are adjustable negative pressure wound treatment systems in the prior art, they cannot accurately monitor the negative pressure value on the dressing. Each time the adjusted negative pressure value is large, it is difficult to accurately adjust the negative pressure value suitable for the patient's wound, and the price is expensive, which cannot meet all the requirements of clinical use. Summary of the Utility Model

[0004] Based on this, the purpose of the utility model is to provide a negative pressure detection circuit for negative pressure wound treatment in view of the deficiencies of the prior art.

[0005] To achieve the above purpose, the utility model adopts the following technical solutions:

[0006] A negative pressure detection circuit for negative pressure wound treatment includes a power supply circuit and a main control MCU circuit connected to each other. It is characterized in that a voltage acquisition circuit is connected between the power supply circuit and the main control MCU circuit, a negative pressure sensor circuit and a negative pressure pump circuit are connected to the main control MCU circuit, the power supply circuit includes a power on / off and protection circuit, a pre-filtering circuit and a post-filtering circuit, and the main control MCU circuit includes a crystal oscillator circuit, a reset circuit and a filtering circuit.

[0007] As a further improvement of the utility model, the negative pressure sensor circuit includes a negative pressure sensor U5. Interface 1 and interface 6 of the negative pressure sensor U5 are connected to the positive pole of amplifier U4.1 through resistor R34. Interface 3 of the negative pressure sensor U5 is connected to the negative pole of amplifier U4.1 through resistor R32. A resistor R31 is connected between the negative pole and the output end of the amplifier U4.1. Resistor R31 is in parallel with capacitor C26. The positive pole of the amplifier U4.1 is grounded through resistor R35.

[0008] As a further improvement of the present utility model, the negative pressure pump circuit includes a motor drive chip U2. The input terminal 6 of the motor drive chip U2 is connected to the IO interface PA10 of the main control MCU circuit. The output terminals 2 and 3 of the motor drive chip U2 are connected to the negative pressure pump P6. The ground terminal 4 of the motor drive chip U2 is grounded through a resistor R13. The ground terminal 4 of the motor drive chip U2 is connected to the positive electrode of the amplifier U4.2 through a resistor R11. The positive electrode of the amplifier U4.2 is grounded through a resistor R14. The resistor R14 is connected in parallel with a capacitor C16. The negative electrode of the amplifier U4.2 is grounded through a resistor R16. A resistor R15 is connected between the negative electrode of the amplifier U4.2 and the output terminal 7 of the amplifier U4.2. The resistor R15 is connected in parallel with a capacitor C18. The output terminal 7 of the amplifier U4.2 is connected to the IO interface PA6 of the main control MCU circuit through a resistor R12.

[0009] As a further improvement of the present utility model, the voltage acquisition circuit includes a resistor R3 and a resistor R4. One end of the resistor R3 is connected to the battery VBAT - 3V. The other end of the resistor R3 is connected to the IO interface PA3. Both ends of the resistor R4 are respectively connected to the IO interface PA3 and the IO interface PA4. The resistor R4 is connected in parallel with a capacitor C11.

[0010] As a further improvement of the present utility model, the power - on / off and protection circuit includes a positive electrode interface P2 connected to the positive electrode of the battery VBAT - 3V, and a negative electrode interface P3 connected to the negative electrode of the battery VBAT - 3V. The positive electrode interface P2 is connected to the drain of the MOS transistor Q3. The negative electrode interface P3 is connected to the gate of the MOS transistor Q3 through a resistor R26. The source of the MOS transistor Q3 is connected to a fuse F1. The fuse F1 is connected to the source of the MOS transistor Q4. The drain of the MOS transistor Q4 is connected to the input terminals 1 and 14 of the power supply chip U3. The enable terminal 2 of the power supply chip U3 is connected to the input terminals 1 and 14 through a resistor R27. The fuse F1 is grounded through a zener diode D4. The drain of the MOS transistor Q4 is grounded through a TVS diode D3. The output terminals 9 and 10 of the power supply chip U3 are connected to the feedback voltage terminal 8 through a resistor R25. The feedback voltage terminal 8 is grounded through a resistor R30. The output terminals 9 and 10 of the power supply chip U3 are grounded through a TVS diode D5. The output voltage of the output terminals 9 and 10 of the power supply chip U3 is VCC - 3.3V.

[0011] As a further improvement of the present utility model, the power-on / off and protection circuit includes a connection between the output voltage VCC-3.3V and the first positive electrode of the double diode D2 through the resistor R20. The first positive electrode of the double diode D2 is connected to the IO interface PB15 of the main control MCU circuit. The negative electrode of the double diode D2 is connected to the key interface KEY-1. The second positive electrode of the double diode D2 is connected to the gate of the MOS transistor Q4 through the resistor R21. The gate of the MOS transistor Q4 is connected to the source of the MOS transistor Q4 through the resistor R24. The second positive electrode of the double diode D2 is connected to the collector of the triode Q2. The emitter of the triode Q2 is grounded. The base of the triode Q2 is connected to the emitter through the resistor R22. The base of the triode Q2 is connected to the IO interface PB14 of the main control MCU circuit through the resistor R23.

[0012] As a further improvement of the present utility model, the front filter circuit includes capacitors C20 and C21 connected to the input terminals 1 and 14 of the power supply chip U3. One ends of the capacitors C20 and C21 are grounded. The rear filter circuit includes capacitors C22, C23, and C24 connected to the output terminals 9 and 10 of the power supply chip U3. One ends of the capacitors C22, C23, and C24 are grounded.

[0013] As a further improvement of the present utility model, a buzzer circuit for prompting is connected to the main control MCU circuit. A storage circuit for storing data is connected to the main control MCU circuit. A key circuit for human-computer interaction is connected to the main control MCU circuit. An LED lamp circuit for displaying the operating state is connected to the main control MCU circuit.

[0014] As a further improvement of the present utility model, a serial port debugging circuit and a chip programming circuit are connected to the main control MCU circuit.

[0015] The beneficial effects of the present utility model are as follows:

[0016] 1. The present utility model provides a negative pressure detection circuit for negative pressure wound treatment. The negative pressure value is monitored through the amplifier circuit structure in the negative pressure sensor circuit, and the monitored negative pressure value is processed by the main control MCU circuit, thereby controlling the negative pressure pump circuit. The negative pressure value is adjusted through the cooperation of the motor drive circuit structure and the amplifier circuit structure in the negative pressure pump circuit, realizing accurate monitoring and accurate adjustment of the negative pressure value. Moreover, the overall circuit structure is simple, and the production and assembly costs are relatively low, which is suitable for mass production.

[0017] 2. The negative pressure sensor circuit of the present utility model adopts a mutually cooperative negative pressure sensor U5 and amplifier U4.1. The circuit is current-limited through resistors R32, R34, and R33 to protect the amplifier U4.1 and the main control MCU chip U1. The amplification factor of the weak negative pressure value signal monitored by the negative pressure sensor U5 is adjusted through resistors R31 and R32, so that the negative pressure value signal falls within the detection range of the main control MCU circuit, and the precise monitoring of the negative pressure value is realized through the cooperation of high-precision resistors and the amplifier U4.1.

[0018] 3. The negative pressure pump circuit of the present utility model adopts a mutually cooperative motor drive chip U2 and amplifier U4.2. The negative pressure pump P6 is switched and controlled through the motor drive chip U2. The amplifier U4.2 is current-limited through resistors R11 and R12, and the resistor R13 is used for voltage division. The amplification factor of the signal monitored on the resistor R13 is adjusted through resistors R15 and R16, so that the voltage value signal falls within the detection range of the main control MCU circuit to ensure the normal operation of the negative pressure pump. The main control MCU circuit controls the motor drive chip U2 based on the negative pressure value monitored within the negative pressure sensor circuit, thereby controlling the rotation or stop of the negative pressure pump P6 to accurately adjust the negative pressure value.

[0019] 4. The power supply circuit of the present utility model adopts a power supply chip U3 with less ripple, and a pre-filter circuit and a post-filter circuit are adopted. The power supply system is stable, which ensures that the voltage signals collected by the negative pressure sensor circuit and the negative pressure pump circuit are more accurate. The battery power is collected through the cooperation of the voltage acquisition circuit and the main control MCU circuit to judge the remaining battery power and avoid power-off during use. Description of the Drawings

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0021] Attached Figure 1 is a schematic diagram of the circuit principle of the present utility model.

[0022] Attached Figure 2 is a schematic diagram of the main control MCU circuit module and its peripheral circuit structure of the present utility model.

[0023] Attached Figure 3 is a schematic diagram of the negative pressure sensor circuit structure of the present utility model.

[0024] Attached Figure 4 is a schematic diagram of the negative pressure pump circuit structure of the present utility model.

[0025] Attached Figure 5 is a schematic diagram of the power supply circuit structure of the present utility model.

[0026] Attached Figure 6 is a schematic diagram of the voltage acquisition circuit structure of the present utility model.

[0027] Attached Figure 7 is a schematic diagram of the buzzer circuit structure of the present utility model.

[0028] Attached Figure 8 is a schematic diagram of the storage circuit structure of the present utility model.

[0029] Attached Figure 9 is a schematic diagram of the key circuit structure of the present utility model.

[0030] Attached Figure 10 is a schematic diagram of the LED lamp circuit structure of the present utility model. Specific embodiments

[0031] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0032] As Figure 1 shown, a negative pressure detection circuit for negative pressure wound treatment includes a power supply circuit and a main control MCU circuit connected to each other. It is characterized in that a voltage acquisition circuit is connected between the power supply circuit and the main control MCU circuit, a negative pressure sensor circuit and a negative pressure pump circuit are connected to the main control MCU circuit, the power supply circuit includes a power on / off and protection circuit, a front filter circuit and a rear filter circuit, the main control MCU circuit includes a crystal oscillator circuit, a reset circuit and a filter circuit, and the power supply circuit supplies power to the main control MCU circuit and the peripheral circuits connected to the main control MCU circuit.

[0033] Preferably, the voltage supplied by the power supply circuit is 3.3V.

[0034] In a specific embodiment, further, the negative pressure sensor circuit includes a negative pressure sensor U5. Interface 1 and interface 6 of the negative pressure sensor U5 are connected to the positive electrode of amplifier U4.1 through resistor R34. Interface 3 of the negative pressure sensor U5 is connected to the negative electrode of amplifier U4.1 through resistor R32. A resistor R31 is connected between the negative electrode and the output end of the amplifier U4.1. The resistor R31 is connected in parallel with capacitor C26. The positive electrode of the amplifier U4.1 is grounded through resistor R35.

[0035] The working principle of the negative pressure sensor circuit is as follows: When the negative pressure sensor circuit operates, the power supply circuit supplies power to the negative pressure sensor U5 through the input interface 2 and supplies power to the amplifier U4.1 through the input interface 8. The negative pressure sensor U5 transmits the detected differential signal to the amplifier U4.1 through the resistors R32 and R34. The resistors R32, R34, and R33 are used for circuit current limiting to protect the amplifier U4.1 and the main control MCU chip U1. The resistors R31 and R32 are used to adjust the amplification factor of the weak negative pressure value signal monitored by the negative pressure sensor U5, and then the amplified signal is transmitted to the IO interface PA5 of the main control MCU circuit through the resistor R33.

[0036] In a specific embodiment, further, the negative pressure pump circuit includes a motor drive chip U2. The input terminal 6 of the motor drive chip U2 is connected to the IO interface PA10 of the main control MCU circuit. The output terminals 2 and 3 of the motor drive chip U2 are connected to the negative pressure pump P6. The ground terminal 4 of the motor drive chip U2 is grounded through the resistor R13. The ground terminal 4 of the motor drive chip U2 is connected to the positive electrode of the amplifier U4.2 through the resistor R11. The positive electrode of the amplifier U4.2 is grounded through the resistor R14. The resistor R14 is connected in parallel with the capacitor C16. The negative electrode of the amplifier U4.2 is grounded through the resistor R16. A resistor R15 is connected between the negative electrode of the amplifier and the output terminal 7 of the amplifier U4.2. The resistor R15 is connected in parallel with the capacitor C18. The output terminal 7 of the amplifier U4.2 is connected to the IO interface PA6 of the main control MCU circuit through the resistor R12.

[0037] The working principle of the negative pressure pump circuit is as follows: When the negative pressure pump circuit operates, the power supply circuit supplies power to the motor drive chip U2 through the input interface 8 and supplies power to the amplifier U4.2 through the same input interface 8 as the amplifier U4.1. The IO interface PA10 of the main control MCU circuit sends a control signal to the motor drive chip U2 through the input terminals 6 and 7 of the motor drive chip U2, thereby controlling the operation of the negative pressure pump P6 through the output terminals 2 and 3 of the motor drive chip U2. The on / off control of the negative pressure pump P6 is performed through the motor drive chip U2. The resistors R11 and R12 are used for current limiting protection of the amplifier U4.2. The resistor R13 is used for voltage division. The resistors R15 and R16 are used to adjust the amplification factor of the signal monitored on the resistor R13, and then the voltage signal is input to the IO interface PA6 of the main control MCU circuit. The main control MCU circuit processes the voltage signal, thereby adjusting the control signal sent to the motor drive chip U2, and then controlling the rotation or stop of the negative pressure pump P6 to accurately adjust the negative pressure value.

[0038] Preferably, the amplifiers U4.1 and U4.2 are of the same chip, and the input voltage and output voltage of the amplifiers U4.1 and U4.2 are rail-to-rail voltages.

[0039] In a specific embodiment, further, the voltage acquisition circuit includes a resistor R3 and a resistor R4. One end of the resistor R3 is connected to the battery VBAT - 3V, the other end of the resistor R3 is connected to the IO interface PA3, both ends of the resistor R4 are respectively connected to the IO interface PA3 and the IO interface PA4, and the resistor R4 is connected in parallel with the capacitor C11.

[0040] In a specific embodiment, further, the power - on / off and protection circuit includes a positive - pole interface P2 connected to the positive pole of the battery VBAT - 3V, a negative - pole interface P3 connected to the negative pole of the battery VBAT - 3V. The positive - pole interface P2 is connected to the drain of the MOS transistor Q3, the negative - pole interface P3 is connected to the gate of the MOS transistor Q3 through the resistor R26, the source of the MOS transistor Q3 is connected to the fuse F1. The MOS transistor Q3 is used to prevent reverse power connection. The fuse F1 is connected to the source of the MOS transistor Q4, the drain of the MOS transistor Q4 is connected to the input terminals 1 and 14 of the power - supply chip U3. The enable terminal 2 of the power - supply chip U3 is connected to the input terminals 1 and 14 through the resistor R27. The fuse F1 is grounded through the zener diode D4 to protect the circuit. The drain of the MOS transistor Q4 is grounded through the TVS diode D3 to protect the circuit. The output terminals 9 and 10 of the power - supply chip U3 are connected to the feedback voltage terminal 8 through the resistor R25. The feedback voltage terminal 8 is grounded through the resistor R30. The resistors R25 and R30 are used to adjust the output voltage. The output terminals 9 and 10 of the power - supply chip U3 are grounded through the TVS diode D5. The output voltage of the output terminals 9 and 10 of the power - supply chip U3 is VCC - 3.3V.

[0041] In a specific embodiment, further, the power - on / off and protection circuit includes a connection between the output voltage VCC - 3.3V and the first positive pole of the double - diode D2 through the resistor R20. The first positive pole of the double - diode D2 is connected to the IO interface PB15 of the main - control MCU circuit. The negative pole of the double - diode D2 is connected to the key interface KEY - 1. The second positive pole of the double - diode D2 is connected to the gate of the MOS transistor Q4 through the resistor R21. The gate of the MOS transistor Q4 is connected to the source of the MOS transistor Q4 through the resistor R24. The second positive pole of the double - diode D2 is connected to the collector of the triode Q2. The emitter of the triode Q2 is grounded. The base of the triode Q2 is connected to the emitter through the resistor R22. The base of the triode Q2 is connected to the IO interface PB14 of the main - control MCU circuit through the resistor R23.

[0042] In a specific embodiment, further, the pre-filter circuit includes capacitors C20 and C21 connected to input terminal 1 and input terminal 14 of power supply chip U3. One ends of capacitors C20 and C21 are grounded. The post-filter circuit includes capacitors C22, C23, and C24 connected to output terminal 9 and output terminal 10 of power supply chip U3. One ends of capacitors C22, C23, and C24 are grounded.

[0043] In a specific embodiment, further, a buzzer circuit for prompting is connected to the main control MCU circuit, a storage circuit for storing data is connected to the main control MCU circuit, a key circuit for human-computer interaction is connected to the main control MCU circuit, and an LED lamp circuit for displaying the operating state is connected to the main control MCU circuit.

[0044] In a specific embodiment, further, a serial port debugging circuit and a chip programming circuit are connected to the main control MCU circuit.

[0045] It can be understood that the above specific description of the present invention is only used to illustrate the present invention and is not limited by the technical solutions described in the embodiments of the present invention. Those of ordinary skill in the art should understand that the present invention can still be modified or equivalently replaced to achieve the same technical effects; as long as the use requirements are met, they are all within the protection scope of the present invention.

[0046] It should also be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover a non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, the elements defined by the statement "including..." do not exclude the presence of additional identical elements in the process, method, article or device including the said elements.

Claims

1. A negative pressure detection circuit for negative pressure wound treatment, comprising a power supply circuit and a main control MCU circuit connected to each other, characterized in that, A voltage acquisition circuit is connected between the power supply circuit and the main control MCU circuit. A negative pressure sensor circuit and a negative pressure pump circuit are connected to the main control MCU circuit. The power supply circuit includes a power-on / off and protection circuit, a front filter circuit, and a rear filter circuit. The main control MCU circuit includes a crystal oscillator circuit, a reset circuit, and a filter circuit; The negative pressure sensor circuit uses a mutually cooperative negative pressure sensor U5 and amplifier U4.

1. Resistors R32, R34, and R33 are used for circuit current limiting to protect amplifier U4.1 and the main control MCU chip U1. Resistors R31 and R32 are used to adjust the amplification factor of the weak negative pressure value signal monitored by the negative pressure sensor U5; The negative pressure pump circuit uses a mutually cooperative motor drive chip U2 and amplifier U4.

2. The motor drive chip U2 is used to control the switch of the negative pressure pump P6. Resistors R11 and R12 are used for current limiting protection of the amplifier U4.

2. Resistor R13 is used for voltage division. Resistors R15 and R16 are used to adjust the amplification factor of the signal monitored on resistor R13.

2. The negative pressure detection circuit for negative pressure wound treatment according to claim 1, wherein The negative pressure sensor circuit includes a negative pressure sensor U5. Interface 1 and interface 6 of the negative pressure sensor U5 are connected to the positive pole of the amplifier U4.1 through resistor R34. Interface 3 of the negative pressure sensor U5 is connected to the negative pole of the amplifier U4.1 through resistor R32. A resistor R31 is connected between the negative pole and the output terminal of the amplifier U4.

1. Resistor R31 is in parallel with capacitor C26. The positive pole of the amplifier U4.1 is grounded through resistor R35.

3. The negative pressure detection circuit for negative pressure wound treatment according to claim 1, wherein The negative pressure pump circuit includes a motor drive chip U2. The input terminal 6 of the motor drive chip U2 is connected to the IO interface PA10 of the main control MCU circuit. The output terminals 2 and 3 of the motor drive chip U2 are connected to the negative pressure pump P6. The ground terminal 4 of the motor drive chip U2 is grounded through resistor R13. The ground terminal 4 of the motor drive chip U2 is connected to the positive pole of the amplifier U4.2 through resistor R11. The positive pole of the amplifier U4.2 is grounded through resistor R14. Resistor R14 is in parallel with capacitor C16. The negative pole of the amplifier U4.2 is grounded through resistor R16. A resistor R15 is connected between the negative pole and the output terminal 7 of the amplifier U4.

2. Resistor R15 is in parallel with capacitor C18. The output terminal 7 of the amplifier U4.2 is connected to the IO interface PA6 of the main control MCU circuit through resistor R12.

4. The negative pressure detection circuit for negative pressure wound treatment according to claim 1, wherein, The voltage acquisition circuit includes resistors R3 and R4. One end of resistor R3 is connected to the battery VBAT - 3V. The other end of resistor R3 is connected to the IO interface PA3. Both ends of resistor R4 are respectively connected to the IO interface PA3 and the IO interface PA4. Resistor R4 is in parallel with capacitor C11.

5. The negative pressure detection circuit for negative pressure wound treatment according to claim 1, characterized in that, The power-on / off and protection circuit includes a positive electrode interface P2 connected to the positive electrode of the battery VBAT - 3V, a negative electrode interface P3 connected to the negative electrode of the battery VBAT - 3V. The positive electrode interface P2 is connected to the drain of MOS transistor Q3. The negative electrode interface P3 is connected to the gate of MOS transistor Q3 through resistor R26. The source of MOS transistor Q3 is connected to fuse F1. Fuse F1 is connected to the source of MOS transistor Q4. The drain of MOS transistor Q4 is connected to input terminals 1 and 14 of power supply chip U3. The enable terminal 2 of power supply chip U3 is connected to input terminals 1 and 14 through resistor R27. Fuse F1 is grounded through zener diode D4. The drain of MOS transistor Q4 is grounded through TVS diode D3. Output terminals 9 and 10 of power supply chip U3 are connected to the feedback voltage terminal 8 through resistor R25. The feedback voltage terminal 8 is grounded through resistor R30. Output terminals 9 and 10 of power supply chip U3 are grounded through TVS diode D5. The voltage output at output terminals 9 and 10 of power supply chip U3 is VCC - 3.3V.

6. The negative pressure detection circuit for negative pressure wound treatment according to claim 5, characterized in that, The power-on / off and protection circuit includes being connected to the first positive electrode of double diode D2 through resistor R20 with the output voltage VCC - 3.3V. The first positive electrode of double diode D2 is connected to the IO interface PB15 of the main control MCU circuit. The negative electrode of double diode D2 is connected to the key interface KEY - 1. The second positive electrode of double diode D2 is connected to the gate of MOS transistor Q4 through resistor R21. The gate of MOS transistor Q4 is connected to the source of MOS transistor Q4 through resistor R24. The second positive electrode of double diode D2 is connected to the collector of triode Q2. The emitter of triode Q2 is grounded. The base of triode Q2 is connected to the emitter through resistor R22. The base of triode Q2 is connected to the IO interface PB14 of the main control MCU circuit through resistor R23.

7. The negative pressure detection circuit for negative pressure wound treatment according to claim 5, characterized in that, The front filter circuit includes capacitors C20 and C21 connected to input terminals 1 and 14 of power supply chip U3. One end of capacitors C20 and C21 is grounded. The rear filter circuit includes capacitors C22, C23, and C24 connected to output terminals 9 and 10 of power supply chip U3. One end of capacitors C22, C23, and C24 is grounded.

8. The negative pressure detection circuit for negative pressure wound treatment according to claim 1, characterized in that A buzzer circuit for prompting, a storage circuit for storing data, a key circuit for human-computer interaction, and an LED lamp circuit for displaying the operating state are connected to the main control MCU circuit.

9. The negative pressure detection circuit for negative pressure wound treatment according to claim 1, wherein A serial port debugging circuit and a chip programming circuit are connected to the main control MCU circuit.

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