Portable ventilator and control circuit

Abstract

The present application discloses a portable ventilator and a control circuit. The control circuit at least includes: a sawtooth voltage generator circuit and a window voltage comparator circuit; the output end of the 555 time base circuit chip is connected to the control end of the 555 time base circuit chip through a first resistor, the power supply end and the reset end are both connected to the first power supply, and the ground end is grounded; the first end of the first capacitor is respectively connected to the trigger input end, the threshold end and the discharge end of the 555 time base circuit chip and connected to the output end of the 555 time base circuit chip through a second resistor and a respiratory frequency setting potentiometer, and the second end is grounded; the window voltage comparator circuit is used to generate an exhalation control signal based on the sawtooth voltage to control the opening and closing of the exhalation solenoid valve to achieve exhalation, and to generate an inhalation control signal to control the opening and closing of the inhalation solenoid valve to achieve inhalation. Due to the widening of the sawtooth wave pulse amplitude, the breathing ratio adjustment range is larger.

Description

Technical Field

[0001] The present application relates to the technical field of ventilators, and in particular to a portable ventilator and a control circuit. Background Art

[0002] As a device that can support human breathing, ventilators are widely used in scenarios such as first aid.

[0003] Related technology, a control circuit of a ventilator includes a 555 time base circuit and a window comparator circuit, wherein the 555 time base circuit can generate a sawtooth wave voltage to output to the window comparator circuit, and the window comparator circuit generates a control signal for exhalation and inspiration based on the sawtooth wave voltage. The breathing ratio is the ratio of the time occupied by an exhalation and an inhalation, and is an important parameter in the ventilator. The breathing ratio of the ventilator is adjustable, but a common problem of most ventilators is that they are limited by the range of the sawtooth wave voltage, and the adjustment range of the breathing ratio is also narrow.

[0004] Therefore, how to achieve a breathing ratio with a wide adjustable range is a problem to be solved urgently in this field. Summary of the invention

[0005] The purpose of this application is to provide a portable ventilator and a control circuit to solve the problems in the related art.

[0006] The purpose of this application is achieved through the following technical solutions:

[0007] A control circuit is used in a portable ventilator, wherein the portable ventilator comprises a negative pressure bottle with an exhalation electromagnetic valve and an oxygen bottle with an inhalation electromagnetic valve; the control circuit comprises at least: a sawtooth voltage generator circuit and a window voltage comparator circuit;

[0008] The sawtooth wave voltage generator circuit at least includes a first capacitor, a first resistor, a second resistor, a breathing frequency setting potentiometer and a 555 time base circuit chip;

[0009] The output end of the 555 time base circuit chip is connected to the control end of the 555 time base circuit chip through the first resistor, the power end and the reset end are both connected to the first power supply, and the ground end is grounded;

[0010] The first end of the first capacitor is respectively connected to the trigger input end, the threshold end and the discharge end of the 555 time base circuit chip and connected to the output end of the 555 time base circuit chip through the second resistor and the breathing frequency setting potentiometer, and the second end is grounded;

[0011] The first end and the second end of the first capacitor are also connected to the window voltage comparator circuit, and are used to output a sawtooth wave voltage to the window voltage comparator circuit;

[0012] The window voltage comparator circuit is used to connect the exhalation solenoid valve and the inhalation solenoid valve respectively, generate an exhalation control signal based on the sawtooth wave voltage to control the opening and closing of the exhalation solenoid valve to achieve exhalation, and generate an inhalation control signal to control the opening and closing of the inhalation solenoid valve to achieve inhalation.

[0013] Optionally, the window voltage comparator circuit includes at least a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a first switch transistor, a second switch transistor, a first diode, a second diode, a breathing ratio setting potentiometer, and a first operational amplifier and a second operational amplifier;

[0014] The inverting input terminal of the first operational amplifier is respectively connected to the first end of the first capacitor and the non-inverting input terminal of the second operational amplifier, the non-inverting input terminal is connected to the first end of the fourth resistor and the first end of the breathing ratio setting potentiometer, and the output terminal is connected to the base of the second switch transistor through the sixth resistor;

[0015] The inverting input terminal of the second operational amplifier is respectively connected to the second end of the fourth resistor and the first end of the third resistor, and the output terminal is connected to the base of the first switch transistor through the fifth resistor;

[0016] The collector of the first switch transistor is connected to the anode of the first diode and is also used to connect to the first end of the interface of the air intake solenoid valve, and the emitter is grounded;

[0017] The collector of the second switch transistor is connected to the anode of the second diode and is also used to connect to the second end of the interface of the exhalation solenoid valve, and the emitter is grounded;

[0018] The second end of the breathing ratio setting potentiometer is grounded;

[0019] The cathode of the first diode, the cathode of the second diode, the first end of the interface of the exhalation solenoid valve, and the second end of the interface of the inhalation solenoid valve are all connected to a first power source;

[0020] When the sawtooth wave voltage is less than the set voltage of the non-inverting input terminal of the first operational amplifier, the output terminal of the first operational amplifier outputs a high level as a first exhalation control signal to drive the exhalation solenoid valve to open; when the sawtooth wave voltage is less than the set voltage of the non-inverting input terminal of the first operational amplifier, the first operational amplifier outputs a low level as a second exhalation control signal to close the exhalation solenoid valve;

[0021] When the sawtooth wave voltage is greater than the voltage at the inverting input terminal of the second operational amplifier, the output terminal of the second operational amplifier outputs a high level as a first air intake control signal, so that the air intake solenoid valve is opened; when the sawtooth wave voltage is greater than the threshold voltage of the 555 time-based circuit chip, the output terminal of the second operational amplifier outputs a low level as a second air intake control signal, so that the air intake solenoid valve is closed.

[0022] Optionally, the first operational amplifier and the second operational amplifier are operational amplifiers in the same dual operational amplifier chip.

[0023] Optionally, the portable ventilator further comprises a vacuum pump connected to the negative pressure bottle; the control circuit further comprises: a first pressure control circuit;

[0024] The first pressure control circuit is used to control the vacuum pump to evacuate the negative pressure bottle.

[0025] Optionally, the first pressure control circuit includes a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, a negative pressure setting potentiometer, a third operational amplifier, a third switching transistor, a third diode and a first pressure sensor for detecting the negative pressure in the negative pressure bottle;

[0026] The non-inverting input terminal of the third operational amplifier is respectively connected to the first end of the seventh resistor, the first end of the negative pressure setting potentiometer, and the first end of the tenth resistor, the inverting input terminal is respectively connected to the first end of the ninth resistor and the output end of the first pressure sensor, and the output terminal is connected to the second end of the tenth resistor and connected to the gate of the third switch transistor through the eighth resistor;

[0027] The source of the third switch transistor is grounded, the drain is connected to the anode of the third diode, and is also used to connect to the first end of the interface of the vacuum pump;

[0028] The second end of the negative pressure setting potentiometer and the second end of the ninth resistor are grounded;

[0029] The cathode of the third diode and the second end of the interface of the vacuum pump are both connected to the first power supply;

[0030] The voltage end of the first pressure sensor and the second end of the seventh resistor are both connected to a second power supply;

[0031] When the absolute value of the negative pressure in the negative pressure bottle detected by the first pressure sensor is less than a set absolute value, the output end of the third operational amplifier outputs a high level to drive the vacuum pump to work and evacuate the negative pressure bottle;

[0032] When the absolute value of the negative pressure in the negative pressure bottle detected by the first pressure sensor is greater than a set absolute value, the output end of the third operational amplifier outputs a low level to stop the vacuum pump from working.

[0033] Optionally, the portable ventilator further comprises a compressor connected to the oxygen cylinder; the control circuit further comprises: a second pressure control circuit;

[0034] The second pressure control circuit is used to control the compressor to compress air into the oxygen cylinder.

[0035] Optionally, the second pressure control circuit includes an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a positive pressure setting potentiometer, a fourth operational amplifier, a fourth switching transistor, a fourth diode and a second pressure sensor for detecting the pressure in the oxygen cylinder;

[0036] The in-phase input terminal of the fourth operational amplifier is respectively connected to the first end of the eleventh resistor, the first end of the thirteenth resistor and the first end of the positive pressure setting potentiometer, the inverting input terminal is respectively connected to the first end of the twelfth resistor and the output end of the second pressure sensor, and the output terminal is connected to the second end of the eleventh resistor and connected to the gate of the fourth switch transistor through the fourteenth resistor;

[0037] The source of the fourth switch transistor is grounded, the drain is connected to the anode of the fourth diode, and is also used to connect to the second end of the interface of the compressor;

[0038] The second end of the positive pressure setting potentiometer and the second end of the twelfth resistor are grounded;

[0039] The cathode of the fourth diode and the first end of the interface of the compressor are both connected to the first power supply;

[0040] The voltage end of the second pressure sensor and the second end of the eleventh resistor are both connected to a second power supply;

[0041] When the internal pressure in the oxygen cylinder detected by the second pressure sensor is lower than the set pressure value, the output terminal of the fourth operational amplifier outputs a high level to drive the compressor to work and compress the air into the oxygen cylinder;

[0042] When the internal pressure of the oxygen cylinder detected by the second pressure sensor is greater than a set pressure value, the output end of the fourth operational amplifier outputs a low level to stop the compressor.

[0043] Optionally, the third operational amplifier and the fourth operational amplifier are operational amplifiers in the same dual operational amplifier chip.

[0044] Optionally, the model of the 555 time base circuit chip includes LM555.

[0045] A portable ventilator comprises a negative pressure bottle with an exhalation electromagnetic valve, an oxygen bottle with an inhalation electromagnetic valve and a control circuit as described in any one of the above.

[0046] This application adopts the above technical solution, which has the following beneficial effects:

[0047] The circuit provided by the scheme of the present application is applied to a portable ventilator, and the output end of the 555 time base circuit chip is fed back to the control end through a positive feedback resistor, which greatly widens the sawtooth wave pulse amplitude. Due to the widening of the sawtooth wave, the slope voltage range is relatively large, which facilitates the adjustment of the window voltage within a wider range, thereby making the breathing ratio adjustment range larger and the adjustment more convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0049] Figure 1 A schematic diagram of the structure of a control circuit provided for one embodiment of the present application.

[0050] Figure 2 This is a partial structural diagram of a ventilator.

[0051] Figure 3 This is a waveform diagram of a sawtooth wave.

[0052] Figure 4 It is a structural schematic diagram of a control circuit provided in another embodiment of the present application.

[0053] Figure 5 It is a structural schematic diagram of a control circuit provided in another embodiment of the present application. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical solution and advantages of the present application clearer, the technical solution of the present application will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other implementation methods obtained by ordinary technicians in the field without creative work belong to the scope of protection of the present application.

[0055] Example

[0056] See also Figure 1 , Figure 1 It is a structural schematic diagram of a control circuit provided by an embodiment of the present application.

[0057] See also Figure 2 , Figure 2 This is a partial structural diagram of a ventilator.

[0058] like Figure 1 and Figure 2 As shown, a control circuit provided in this embodiment is applied to a portable ventilator, wherein the portable ventilator comprises a negative pressure bottle 100 having an exhalation solenoid valve J2 and an oxygen bottle 200 having an inhalation solenoid valve J1; the control circuit comprises at least: a sawtooth voltage generator circuit 300 and a window voltage comparator circuit 400;

[0059] The sawtooth wave voltage generator circuit 300 at least includes a first capacitor C1, a first resistor R1, a second resistor R2, a breathing frequency setting potentiometer RP1 and a 555 time base circuit chip U1;

[0060] The output terminal Q of the 555 time base circuit chip U1 is connected to the control terminal CVolt of the 555 time base circuit chip U1 through the first resistor R1, the power terminal VCC and the reset terminal R are both connected to the first power supply V1, and the ground terminal GND is grounded;

[0061] The first end of the first capacitor C1 is respectively connected to the trigger input terminal TRIG, the threshold terminal THR and the discharge terminal DIS of the 555 time base circuit chip U1 and connected to the output terminal Q of the 555 time base circuit chip U1 through the second resistor R2 and the breathing frequency setting potentiometer RP1, and the second end is grounded;

[0062] The first end and the second end of the first capacitor C1 are also connected to the window voltage comparator circuit 400, and are used to output a sawtooth wave voltage to the window voltage comparator circuit 400;

[0063] The window voltage comparator circuit 400 is used to connect the exhalation solenoid valve J2 and the inhalation solenoid valve J1 respectively, and generate an exhalation control signal based on the sawtooth wave voltage to control the opening and closing of the exhalation solenoid valve J2 to achieve exhalation, and generate an inhalation control signal to control the opening and closing of the inhalation solenoid valve J1 to achieve inhalation.

[0064] It should be noted that a general ventilator includes basic structures such as a negative pressure bottle 100, an oxygen bottle 200, and a vacuum pump 600 arranged on a ventilator body 000.

[0065] Among them, the first end of the negative pressure bottle 100 is provided with an exhalation solenoid valve J2, and the second end is connected to the vacuum pump 600. The negative pressure bottle 100 is used to generate a negative pressure environment under the action of the vacuum pump 600. When the exhalation solenoid valve J2 is opened, waste gas such as carbon dioxide exhaled by the human body is sucked into the negative pressure bottle 100 through the exhalation solenoid valve J2. The vacuum pump 600 is used to evacuate the negative pressure bottle 100 so that the negative pressure bottle 100 maintains a negative pressure environment and discharges the extracted waste gas.

[0066] An inhalation electromagnetic valve J1 is disposed at the first end of the oxygen cylinder 200. The oxygen cylinder 100 is used to provide oxygen to the human body when the inhalation electromagnetic valve J1 is opened.

[0067] In implementation, the inhalation solenoid valve J1 may be a normally closed solenoid valve; the exhalation solenoid valve J2 may also be a normally closed solenoid valve, and any suitable normally closed solenoid valve available on the market may be used.

[0068] The respiratory frequency setting potentiometer RP1 can adjust the respiratory frequency. Specifically, a linear potentiometer can be used. The available models include 3296W potentiometer. The potentiometer generally includes two fixed contacts and a moving contact. The moving contact is connected to one of the fixed contacts. The two ends of the above-mentioned respiratory frequency setting potentiometer RP1 refer to the two fixed contacts.

[0069] The implementation of the basic structures of the above-mentioned ventilators are all existing mature technologies, which can be implemented by referring to relevant technologies and will not be elaborated here. This application focuses on improving the control circuit in the ventilator.

[0070] The 555 time base circuit is a combination integrated circuit that cleverly combines analog functions and logic functions on the same silicon chip. For example, the LM555 time base circuit chip is powerful, flexible, and has a wide range of applications. It can be used to generate a variety of pulse signals. For a ventilator, a sawtooth wave voltage needs to be generated, such as Figure 3 The waveform of the sawtooth voltage shown, the horizontal axis is time t, and the vertical axis is voltage value V. It can be seen from the figure that the sawtooth wave can provide a ramp voltage to supply the window voltage comparator to distinguish the exhalation control signal and the inhalation control signal.

[0071] Generally, the 555 timing circuit chip includes 8 pins, which are introduced according to the pin numbers: pin 1 is the ground terminal GND, pin 2 is the trigger input terminal TRIG, pin 3 is the output terminal Q, pin 4 is the reset terminal R, pin 5 is the control terminal CVolt, pin 6 is the threshold terminal THR, pin 7 is the discharge terminal DIS, and pin 8 is the power supply terminal VCC.

[0072] In the solution of the present application, the conventional wiring of the 555 time base circuit chip is creatively changed, and the output end is fed back to the control end through a positive feedback resistor (i.e., the first resistor R1R1), so that the voltage of the control end is not a constant 2 / 3Vcc when the output end outputs a high level and a low level, while if no positive feedback is added, the voltage of the control end is constant at 2 / 3Vcc. When the positive feedback resistor is added, the voltage of the control end of the 555 time base circuit chip is greater than 2 / 3Vcc when the output end outputs a high level, and the voltage of the control end is less than 2 / 3Vcc when the output end outputs a low level, thereby widening the amplitude of the sawtooth wave. Because the sawtooth wave constructed by the conventional connection 555 time base circuit chip is 1 / 3vcc-2 / 3Vcc, that is, the net amplitude is 1 / 3Vcc, that is, the lowest voltage of the sawtooth wave is 1 / 3Vcc, and the highest voltage is 2 / 3Vcc. The trigger level of the trigger input terminal of the 555 time base circuit chip is 1 / 2 of the voltage value of the control terminal, and the threshold of the threshold terminal is the voltage value of the control terminal. When we increase the positive feedback resistor, we can control the control terminal voltage to 9 / 10Vcc when the output terminal outputs a high level and 1 / 10Vcc when the output is a low level, thereby controlling the sawtooth wave to 1 / 20Vcc-9 / 10Vcc, that is, the net amplitude is 8.5 / 10Vcc, which greatly widens the sawtooth wave pulse amplitude. Due to the widening of the sawtooth wave, the slope voltage range is relatively large, which is convenient for adjusting the window voltage in a wider range, so that the breathing ratio adjustment range is larger and the adjustment is more convenient.

[0073] It should be noted that the first power supply can be a battery or a DC regulated power supply, which are directly available on the market and are not described in detail here. The voltage value of the first power supply can be set according to the actual needs of the 555 time base circuit chip, such as 12V, etc.

[0074] There are many specific structures of the above-mentioned window voltage comparator circuit. In some embodiments, Figure 4 As shown, the window voltage comparator circuit at least includes a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a first switch transistor VT1, a second switch transistor VT2, a first diode D1, a second diode D2, a breathing ratio setting potentiometer RP2 and a first operational amplifier U2A and a second operational amplifier U2B;

[0075] The inverting input terminal of the first operational amplifier U2A is respectively connected to the first end of the first capacitor C1 and the non-inverting input terminal of the second operational amplifier U2B, the non-inverting input terminal is connected to the first end of the fourth resistor R4 and the first end of the breathing ratio setting potentiometer RP2, and the output terminal is connected to the base of the second switch transistor VT2 through the sixth resistor R6;

[0076] The inverting input terminal of the second operational amplifier U2B is respectively connected to the second end of the fourth resistor R4 and the first end of the third resistor R3, and the output terminal is connected to the base of the first switch transistor VT1 through the fifth resistor R5;

[0077] The collector of the first switch transistor VT1 is connected to the anode of the first diode D1 and is also used to connect to the first end of the interface of the air intake solenoid valve J1, and the emitter is grounded;

[0078] The collector of the second switch transistor VT2 is connected to the anode of the second diode D2 and is also used to connect to the second end of the interface of the exhalation solenoid valve J2, and the emitter is grounded;

[0079] A second end of the breathing ratio setting potentiometer RP2 is grounded;

[0080] The cathode of the first diode D1, the cathode of the second diode D2, the first end of the interface of the exhalation solenoid valve J2, and the second end of the interface of the inhalation solenoid valve J1 are all connected to a first power source;

[0081] When the sawtooth wave voltage is less than the set voltage of the non-inverting input terminal of the first operational amplifier U2A, the output terminal of the first operational amplifier U2A outputs a high level as a first exhalation control signal to drive the exhalation solenoid valve J2 to open; when the sawtooth wave voltage is less than the set voltage of the non-inverting input terminal of the first operational amplifier U2A, the first operational amplifier U2A outputs a low level as a second exhalation control signal to close the exhalation solenoid valve J2;

[0082] When the sawtooth wave voltage is greater than the voltage at the inverting input terminal of the second operational amplifier U2B, the output terminal of the second operational amplifier U2B outputs a high level as the first air intake control signal, so that the air intake solenoid valve J1 is opened; when the sawtooth wave voltage is greater than the threshold voltage of the 555 time base circuit chip, the output terminal of the second operational amplifier U2B outputs a low level as the second air intake control signal, so that the air intake solenoid valve J1 is closed.

[0083] There are many types of the first switch transistor VT1 and the second switch transistor VT2, for example, they may be triodes, or field effect transistors, such as MOS transistors, and so on.

[0084] To simplify the circuit design, the first operational amplifier U2A and the second operational amplifier U2B are operational amplifiers in the same dual operational amplifier chip U2. The model of the dual operational amplifier chip U2 may include LM358. Based on this model, a window voltage comparator circuit is constructed. Based on this, the second operational amplifier U2A is also connected to the first power supply and ground.

[0085] The non-inverting input terminal of the first operational amplifier U2A provides a set voltage.

[0086] When the sawtooth wave voltage (that is, the terminal voltage of the first capacitor C1) is less than the set voltage of the in-phase input terminal of the first operational amplifier U2A, the output terminal of the first operational amplifier U2A outputs a high level as an exhalation control signal, and the second switch transistor VT2 obtains the base current and is saturated and turned on, driving the exhalation solenoid valve J2 to open, so that the negative pressure in the negative pressure bottle quickly discharges waste gases such as carbon dioxide exhaled by the human body. With the increase of the terminal voltage of the first capacitor C1, when the sawtooth wave voltage is greater than the set voltage of the in-phase input terminal of the first operational amplifier U2A, the output terminal of the first operational amplifier U2A outputs a low level, and the exhalation solenoid valve J2 is closed. At this time, because of the existence of the fourth resistor R4, the voltage of the inverting input terminal of the second operational amplifier U2B is still greater than the voltage of its in-phase input terminal, so the second operational amplifier U2B also outputs a low level, simulating a short stay time of human breathing after exhalation. Adjusting the value of the fourth resistor R4 can adjust this pause time. Subsequently, as the terminal voltage of the first capacitor C1 continues to rise, when the sawtooth wave voltage rises to a voltage greater than the voltage of the inverting input terminal of the second operational amplifier U2B, the output terminal of the second operational amplifier U2B outputs a high level, and the first switching transistor VT1 obtains the base current and is saturated and turned on, driving the inhalation solenoid valve J1 to open, and the gas in the oxygen cylinder enters the breathing channel through the inhalation solenoid valve J1 to supply the human body. As the terminal voltage of the first capacitor C1 continues to increase, the output end of the second operational amplifier U2B continues to output a high level. When the terminal voltage of the first capacitor C1 increases to about 9 / 10Vcc, which is greater than the threshold voltage of the 555 time-base circuit chip U1, the output end of the 555 time-base circuit chip U1 flips to output a low level. At this time, the internal discharge transistor of the 555 time-base circuit chip U1 is saturated and turned on, and the first capacitor C1 is quickly discharged to about 1 / 20Vcc through the discharge end. At the same time, the output end of the second operational amplifier U2B outputs a low level, the output end of the first operational amplifier U2A outputs a high level, and the output end of the 555 time-base circuit chip U1 immediately jumps to output a high level. Through the second resistor R2, the breathing frequency setting potentiometer RP1 charges the first capacitor C1 so that the terminal voltage of the first capacitor C1 begins to rise again. In this way, the terminal voltage of the first capacitor C1 is a sawtooth wave pulse.

[0087] Among them, R2 is a protective resistor, and its function is to prevent the breathing frequency setting potentiometer RP1 from being adjusted to a resistance of 0, thereby protecting the 555 time base circuit.

[0088] The breathing ratio setting potentiometer RP2 can adjust the breathing ratio. Specifically, a linear potentiometer can be used, and the available models include a 3296W potentiometer.

[0089] If the power supply voltage is 12V, the LM555 time base circuit chip is used, the value of the first resistor R1 is 2K ohms, the value of the second resistor R2 is 2K ohms, the value of the third resistor R3 is 10K ohms, the value of the fourth resistor R4 is 2K ohms, the value of the fifth resistor R5 is 2K ohms, the value of the sixth resistor R6 is 2K ohms, the value of the breathing frequency setting potentiometer RP1 is 500K ohms, the value of the breathing ratio setting potentiometer RP2 is 20K ohms, the value of the first capacitor C1 is 22uF, the first switch transistor VT1 and the second switch transistor VT2 are triodes of model SS8050. At this time, a comparator is implemented to determine whether the voltage at the input end is within the range of 2V to 3.6V. When the input voltage is below 2V and above 3.6V, the output end is low potential, and when the input voltage is within the range of 2V to 3.6V, the output end is high potential.

[0090] When the portable ventilator further includes a vacuum pump 600 connected to the negative pressure bottle 100, Figure 5As shown, the control circuit may further include: a first pressure control circuit 700; the first pressure control circuit 700 is used to control the vacuum pump 600 to evacuate the negative pressure bottle 100, and specifically includes a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a negative pressure setting potentiometer RP3, a third operational amplifier U3A, a third switch transistor VT3, a third diode D3 and a first pressure sensor U4 for detecting the negative pressure in the negative pressure bottle; the in-phase input terminal of the third operational amplifier U3A is respectively connected to the first end of the seventh resistor R7 and the first end of the negative pressure setting potentiometer RP3 and the first end of the tenth resistor R10, the inverting input terminal is respectively connected to the first end of the ninth resistor R9 and the output terminal OUT of the first pressure sensor U4, the output terminal is connected to the second end of the tenth resistor R10 and is connected to the gate of the third switch transistor VT3 through the eighth resistor R8; the third switch transistor The source of the body tube VT3 is grounded, and the drain is connected to the positive electrode of the third diode D3, and is also used to connect the first end of the interface of the vacuum pump 600; the second end of the negative pressure setting potentiometer RP3 and the second end of the ninth resistor R9 are grounded; the cathode of the third diode D3 and the second end of the interface of the vacuum pump 600 are both connected to the first power supply V1; the voltage end VDD of the first pressure sensor U4 and the second end of the seventh resistor R7 are both connected to the second power supply V2; when the absolute value of the negative pressure in the negative pressure bottle 100 detected by the first pressure sensor U4 is less than the set absolute value, the output end of the third operational amplifier U3A outputs a high level to drive the vacuum pump 600 to work and evacuate the negative pressure bottle 100; when the absolute value of the negative pressure in the negative pressure bottle 100 detected by the first pressure sensor U4 is greater than the set absolute value, the output end of the third operational amplifier U3A outputs a low level to stop the vacuum pump 600 from working.

[0091] In addition, the ground terminal GND of the first pressure sensor U4 is grounded. The first pressure sensor U4 can be, but is not limited to, a pressure sensor of model XGZP6857020KPGN, and its applicable range is -20KPa-0KPa. As a home ventilator, a negative pressure of about -10KPA can meet the requirements.

[0092] The vacuum pump 600 may be a small silent vacuum pump 600 with a DC voltage of 12V and a flow rate of about 15L.

[0093] The third switch transistor can be, but is not limited to, a field effect transistor such as a triode or a MOS transistor.

[0094] The non-inverting input terminal of the third operational amplifier U3A provides a set voltage.

[0095] As the exhaust gas enters the negative pressure bottle, the absolute value of the negative pressure in the negative pressure bottle becomes smaller. When the absolute value of the negative pressure in the negative pressure bottle detected by the first pressure sensor U4 is less than the set absolute value, the voltage at the output terminal OUT of the first pressure sensor U4 is less than the set voltage, so that the voltage at the in-phase input terminal of the third operational amplifier U3A is greater than the voltage at the inverting input terminal. The output terminal of the third operational amplifier U3A outputs a high level, and the third switching transistor VT3 obtains the gate G driving voltage and is saturated and turned on, driving the vacuum pump 600 to work. As the vacuum pump 600 works, the inside of the negative pressure bottle The pressure decreases. When the absolute value of the negative pressure is greater than the set absolute value, the voltage output by the output terminal OUT of the first pressure sensor U4 is greater than the set voltage, so that the voltage at the inverting input terminal of the third operational amplifier U3A is greater than the voltage at its non-inverting input terminal. The third operational amplifier U3A outputs a low level, and the vacuum pump 600 stops working. At this time, due to the addition of the positive feedback resistor (i.e., the twelfth resistor R12), the voltage at the non-inverting input terminal of the third operational amplifier U3A is reduced. In this way, the vacuum pump 600 can be prevented from frequently starting near the set absolute value.

[0096] The negative pressure setting potentiometer RP3 can adjust the absolute value of the absolute value of the negative pressure. Specifically, a linear potentiometer can be used, and the models that can be used include a 3296W potentiometer.

[0097] The gas provided by the oxygen cylinder can be pure oxygen, of course, or compressed air. Based on this, in practice, the air can also be compressed into the oxygen cylinder by the compressor 800 for human breathing. At this time, Figure 2 As shown, the portable ventilator also includes a compressor 800 connected to the oxygen cylinder; Figure 5As shown, the control circuit also includes: a second pressure control circuit 900; the second pressure control circuit 900 is used to control the compressor to compress air into the oxygen cylinder, and specifically may include an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, a positive pressure setting potentiometer RP4, a fourth operational amplifier U3B, a fourth switch transistor VT4, a fourth diode and a second pressure sensor U5 for detecting the pressure in the oxygen cylinder; the in-phase input terminal of the fourth operational amplifier U3B is respectively connected to the first end of the eleventh resistor R11, the first end of the thirteenth resistor R13 and the first end of the positive pressure setting potentiometer RP4, the inverting input terminal is respectively connected to the first end of the twelfth resistor R12 and the output terminal OUT of the second pressure sensor U5, the output terminal is connected to the second end of the eleventh resistor R11 and is connected to the gate of the fourth switch transistor VT4 through the fourteenth resistor R14; the The source of the fourth switch transistor VT4 is grounded, the drain is connected to the anode of the fourth diode, and is also used to connect the second end of the interface of the compressor 800; the second end of the positive pressure setting potentiometer RP4 and the second end of the twelfth resistor R12 are grounded; the cathode of the fourth diode D4 and the first end of the interface of the compressor 800 are both connected to the first power supply; the voltage end VDD of the second pressure sensor U5 and the second end of the eleventh resistor R11 are both connected to the second power supply V2; when the internal pressure in the oxygen cylinder 200 detected by the second pressure sensor U5 is less than the set pressure value, the output end of the fourth operational amplifier U3B outputs a high level to drive the compressor 800 to work and compress air into the oxygen cylinder 200; when the internal pressure of the oxygen cylinder 200 detected by the second pressure sensor U5 is greater than the set pressure value, the output end of the fourth operational amplifier U3B outputs a low level to stop the compressor 800 from working.

[0098] In addition, the ground terminal GND of the second pressure sensor U5 is grounded. The second pressure sensor U5 can be, but is not limited to, a pressure sensor of model XGZP6857020KPG, and its applicable range is 0-20KPa.

[0099] To simplify circuit design, the third operational amplifier U3A and the fourth operational amplifier U3B are operational amplifiers in the same dual operational amplifier chip U3, the model of which may include LM358. Based on this, the third operational amplifier U3A is also connected to the first power supply and ground.

[0100] The non-inverting input terminal of the fourth operational amplifier U3B provides a set voltage.

[0101] As the gas in the oxygen cylinder is discharged, the pressure gradually decreases. When the internal pressure of the oxygen cylinder detected by the second pressure sensor U5 is less than the set pressure value, the voltage of the output terminal OUT of the second pressure sensor U5 is less than the set voltage, the voltage of the inverting input terminal of the fourth operational amplifier U3B is less than the voltage of the non-inverting input terminal, the fourth operational amplifier U3B outputs a high level, the fourth switch transistor VT4 obtains the gate G driving voltage and is saturated and turned on, the compressor 800 working power is turned on to make the compressor 800 work, and the compressor 800 compresses air into the oxygen cylinder. When the compressor 800 works to make the internal pressure of the oxygen cylinder rise to the set pressure value, the voltage of the output terminal OUT of the second pressure sensor U5 is greater than the set voltage, so that the voltage of the inverting input terminal of the fourth operational amplifier U3B is greater than the voltage of the non-inverting input terminal, and the fourth operational amplifier U3B outputs a low level. At this time, due to the action of the positive feedback resistor (i.e., the thirteenth resistor R13), the voltage of the non-inverting input terminal is reduced, which can ensure that the compressor 800 will not be frequently started near the set pressure value.

[0102] The positive pressure setting potentiometer RP4 can adjust the set pressure value of the oxygen cylinder. Specifically, a linear potentiometer can be used, and the models that can be used include a 3296W potentiometer.

[0103] Compressor 800 can choose a silent air compressor, and multiple compressors can be selected to work in parallel to reduce noise during operation. For example, two compressors with a flow rate of 10L can be used to work in parallel.

[0104] It should be noted that the second power supply can be obtained directly from the first power supply using a voltage stabilizing circuit, or an independent power supply can be directly used, such as a battery or a DC regulated power supply. The voltage value of the second power supply can be set according to actual needs. For the pressure sensor models listed above, a 5V power supply can be selected.

[0105] In a specific implementation, in a possible embodiment, the model of the first pressure sensor is XGZP6857020KPGN, the value of the seventh resistor R7 can be 10K ohms, the value of the eighth resistor R8 can be 2K ohms, the value of the ninth resistor can be 10K ohms, the resistance value of the tenth resistor can be 47K ohms, the maximum resistance value of the negative pressure setting potentiometer RP3 can be 100K ohms, the third switch transistor VT3 is a MOS tube with a model of 2N60C, and the model of the second pressure sensor is XGZP6857020KPG, the value of the eleventh resistor R11 can be 10K ohms, the value of the twelfth resistor R12 can be 10K ohms, the value of the thirteenth resistor R13 can be 47K ohms, the resistance value of the fourteenth resistor R14 can be 2K ohms, the maximum resistance value of the positive pressure setting potentiometer RP4 can be 100K ohms, the fourth switch transistor VT4 is a MOS tube of model 2N60C, and accordingly, the voltage of the first power supply is 12V, and the voltage of the second power supply is 5V. Here, an example of a possible parameter value of the device is given, which is not limited.

[0106] The function of D1 to D4 above is to protect the switching transistor, because the solenoid valve and the motor are both inductive loads, which will generate reverse electromotive force when turned off.

[0107] Traditional ventilators are always in a continuous oxygen supply state regardless of the exhalation or inhalation phase. In the solution of the present application, because inhalation and exhalation do not work at the same time, the exhalation solenoid valve is turned off during inhalation, and the inhalation solenoid valve is turned off during exhalation. At this time, the gas in the oxygen cylinder will not flow out, because there is no need for oxygen supply during exhalation. This can reduce unnecessary waste, especially when the oxygen cylinder supplies pure oxygen, the oxygen supply time can be extended. In places where there is no oxygen supply, oxygen cylinders of 5L or more can be used to supply oxygen to ensure sufficient gas.

[0108] The solution of the present application introduces negative pressure to help breathing, and adopts a discontinuous air supply method during the inhalation process. The solenoid valve is opened to supply air only during the inhalation stage, thereby saving compressed air. The advantage of this discontinuous air supply is that a relatively small power compressor can be used to reduce the working noise of the air compressor. The small power compressor is smaller in size, which also reduces the volume and weight of the whole machine, thereby achieving the purpose of portability.

[0109] Another embodiment of the present application further provides a portable ventilator, comprising a negative pressure bottle with an exhalation solenoid valve, an oxygen bottle with an inhalation solenoid valve, and a control circuit as described in any of the above embodiments.

[0110] The derivation process of the beneficial effects of this embodiment is generally similar to the derivation process of the beneficial effects brought about by the above-mentioned control circuit, and will not be repeated here.

[0111] The specific implementation scheme of this embodiment can refer to the relevant description in the embodiment of the above control circuit, which will not be repeated here.

[0112] It can be understood that the same or similar parts of the above embodiments can be referenced to each other, and the contents not described in detail in some embodiments can refer to the same or similar contents in other embodiments.

[0113] It should be noted that, in the description of this application, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In addition, in the description of this application, unless otherwise specified, the meaning of "plurality" refers to at least two.

[0114] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0115] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A control circuit, characterized in that: Applicable to a portable ventilator, the portable ventilator comprising a negative pressure bottle with an exhalation solenoid valve and an oxygen bottle with an inhalation solenoid valve; The control circuit at least includes: a sawtooth voltage generator circuit and a window voltage comparator circuit; The sawtooth wave voltage generator circuit at least includes a first capacitor, a first resistor, a second resistor, a breathing frequency setting potentiometer and a 555 time base circuit chip; The output end of the 555 time base circuit chip is connected to the control end of the 555 time base circuit chip through the first resistor, the power end and the reset end are both connected to the first power supply, and the ground end is grounded; The first end of the first capacitor is respectively connected to the trigger input end, the threshold end and the discharge end of the 555 time base circuit chip and connected to the output end of the 555 time base circuit chip through the second resistor and the breathing frequency setting potentiometer, and the second end is grounded; The first end and the second end of the first capacitor are also connected to the window voltage comparator circuit, and are used to output a sawtooth wave voltage to the window voltage comparator circuit; The window voltage comparator circuit is used to connect the exhalation solenoid valve and the inhalation solenoid valve respectively, generate an exhalation control signal based on the sawtooth wave voltage to control the opening and closing of the exhalation solenoid valve to achieve exhalation, and generate an inhalation control signal to control the opening and closing of the inhalation solenoid valve to achieve inhalation; Wherein, the window voltage comparator circuit at least includes a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a first switch transistor, a second switch transistor, a first diode, a second diode, a breathing ratio setting potentiometer and a first operational amplifier and a second operational amplifier; The inverting input terminal of the first operational amplifier is respectively connected to the first end of the first capacitor and the non-inverting input terminal of the second operational amplifier, the non-inverting input terminal is connected to the first end of the fourth resistor and the first end of the breathing ratio setting potentiometer, and the output terminal is connected to the base of the second switch transistor through the sixth resistor; The inverting input terminal of the second operational amplifier is respectively connected to the second end of the fourth resistor and the first end of the third resistor, and the output terminal is connected to the base of the first switch transistor through the fifth resistor; The collector of the first switch transistor is connected to the anode of the first diode and is also used to connect to the first end of the interface of the air intake solenoid valve, and the emitter is grounded; The collector of the second switch transistor is connected to the anode of the second diode and is also used to connect to the second end of the interface of the exhalation solenoid valve, and the emitter is grounded; The second end of the breathing ratio setting potentiometer is grounded; The cathode of the first diode, the cathode of the second diode, the first end of the interface of the exhalation solenoid valve, and the second end of the interface of the inhalation solenoid valve are all connected to a first power source; When the sawtooth wave voltage is less than the set voltage of the non-inverting input terminal of the first operational amplifier, the output terminal of the first operational amplifier outputs a high level as a first exhalation control signal to drive the exhalation solenoid valve to open; when the sawtooth wave voltage is less than the set voltage of the non-inverting input terminal of the first operational amplifier, the first operational amplifier outputs a low level as a second exhalation control signal to close the exhalation solenoid valve; When the sawtooth wave voltage is greater than the voltage at the inverting input terminal of the second operational amplifier, the output terminal of the second operational amplifier outputs a high level as a first air intake control signal, so that the air intake solenoid valve is opened; when the sawtooth wave voltage is greater than the threshold voltage of the 555 time-based circuit chip, the output terminal of the second operational amplifier outputs a low level as a second air intake control signal, so that the air intake solenoid valve is closed.

2. The control circuit according to claim 1, characterized in that: The first operational amplifier and the second operational amplifier are operational amplifiers in the same dual operational amplifier chip.

3. The control circuit according to claim 1, characterized in that: The portable ventilator further comprises a vacuum pump connected to the negative pressure bottle; the control circuit further comprises: a first pressure control circuit; The first pressure control circuit is used to control the vacuum pump to evacuate the negative pressure bottle.

4. The control circuit according to claim 3, characterized in that: The first pressure control circuit includes a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, a negative pressure setting potentiometer, a third operational amplifier, a third switching transistor, a third diode and a first pressure sensor for detecting the negative pressure in the negative pressure bottle; The non-inverting input terminal of the third operational amplifier is respectively connected to the first end of the seventh resistor, the first end of the negative pressure setting potentiometer, and the first end of the tenth resistor, the inverting input terminal is respectively connected to the first end of the ninth resistor and the output end of the first pressure sensor, and the output terminal is connected to the second end of the tenth resistor and connected to the gate of the third switch transistor through the eighth resistor; The source of the third switch transistor is grounded, the drain is connected to the anode of the third diode, and is also used to connect to the first end of the interface of the vacuum pump; The second end of the negative pressure setting potentiometer and the second end of the ninth resistor are grounded; The cathode of the third diode and the second end of the interface of the vacuum pump are both connected to the first power supply; The voltage end of the first pressure sensor and the second end of the seventh resistor are both connected to a second power supply; When the absolute value of the negative pressure in the negative pressure bottle detected by the first pressure sensor is less than a set absolute value, the output end of the third operational amplifier outputs a high level to drive the vacuum pump to work and evacuate the negative pressure bottle; When the absolute value of the negative pressure in the negative pressure bottle detected by the first pressure sensor is greater than a set absolute value, the output end of the third operational amplifier outputs a low level to stop the vacuum pump from working.

5. The control circuit according to claim 4, characterized in that: The portable ventilator further comprises a compressor connected to the oxygen cylinder; the control circuit further comprises: a second pressure control circuit; The second pressure control circuit is used to control the compressor to compress air into the oxygen cylinder.

6. The control circuit according to claim 5, characterized in that: The second pressure control circuit includes an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a positive pressure setting potentiometer, a fourth operational amplifier, a fourth switching transistor, a fourth diode and a second pressure sensor for detecting the pressure in the oxygen cylinder; The in-phase input terminal of the fourth operational amplifier is respectively connected to the first end of the eleventh resistor, the first end of the thirteenth resistor and the first end of the positive pressure setting potentiometer, the inverting input terminal is respectively connected to the first end of the twelfth resistor and the output end of the second pressure sensor, and the output terminal is connected to the second end of the eleventh resistor and connected to the gate of the fourth switch transistor through the fourteenth resistor; The source of the fourth switch transistor is grounded, the drain is connected to the anode of the fourth diode, and is also used to connect to the second end of the interface of the compressor; The second end of the positive pressure setting potentiometer and the second end of the twelfth resistor are grounded; The cathode of the fourth diode and the first end of the interface of the compressor are both connected to the first power supply; The voltage end of the second pressure sensor and the second end of the eleventh resistor are both connected to a second power supply; When the internal pressure in the oxygen cylinder detected by the second pressure sensor is lower than the set pressure value, the output terminal of the fourth operational amplifier outputs a high level to drive the compressor to work and compress the air into the oxygen cylinder; When the internal pressure of the oxygen cylinder detected by the second pressure sensor is greater than a set pressure value, the output end of the fourth operational amplifier outputs a low level to stop the compressor.

7. The control circuit according to claim 6, characterized in that: The third operational amplifier and the fourth operational amplifier are operational amplifiers in the same dual operational amplifier chip.

8. The control circuit according to claim 1, characterized in that: The models of the 555 time base circuit chip include LM555.

9. A portable ventilator, characterized in that: The invention comprises a negative pressure bottle with an exhalation electromagnetic valve, an oxygen bottle with an inhalation electromagnetic valve and a control circuit as claimed in any one of claims 1 to 8.

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