Miniature air pump

Abstract

The invention discloses a miniature air pump, and relates to the technical field of air pumps. The miniature air pump is applied to a medical detection instrument, and the medical detection instrument comprises a battery. A control device; the input end of the driving circuit is electrically connected with the output end of the battery, the controlled end is electrically connected with the control device, the output end is electrically connected with the input end of the motor, and the driving circuit is used for adjusting the driving power of the motor according to the driving signal output by the control device; the input end of the voltage detection circuit is electrically connected with the output end of the battery, the output end is electrically connected with the control device, and the voltage detection circuit is used for detecting the output voltage of the battery and outputting a voltage detection signal; the output end of the leakage detection circuit is electrically connected with the control device, and the leakage detection circuit is used for detecting the sealing state in the miniature air pump and outputting a leakage detection signal; the control device is used for outputting a corresponding driving signal to the driving circuit according to the voltage detection signal and the leakage detection signal. The working stability of the micro air pump is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of air pumps, and particularly to a micro air pump. Background Art

[0002] A portable blood pressure monitor is mainly used to measure the arterial blood pressure of the human body, which is one of the important indicators for evaluating cardiovascular health. When using a portable blood pressure monitor, a micro air pump inflates the cuff until the pressure inside the cuff is sufficient to temporarily block arterial blood flow. Then, the cuff gradually deflates, and at the same time, the built-in pressure sensor monitors the change in pressure inside the cuff. As the cuff pressure drops, blood begins to flow again, and the pulsation signal generated at this time is analyzed to determine the systolic and diastolic blood pressure values. If there is a leak in the micro air pump or the amount of air inflated into the cuff fails to reach the preset value, this will directly affect the working stability and efficiency of the portable blood pressure monitor. When there is a leak in the micro air pump or the amount of air inflated into the cuff fails to reach the preset value, the cuff cannot maintain the required stable pressure, resulting in too rapid a pressure drop during the measurement process or the inability to reach the required maximum pressure, which will lead to inaccurate blood pressure readings. In addition, the leak in the micro air pump will also cause the portable blood pressure monitor to take a longer time to reach the required maximum pressure.

[0003] In addition, a portable blood pressure monitor usually uses a battery to supply power to the motor in the micro air pump to meet the convenience requirement. However, since the output voltage of the battery changes with the battery level, it is difficult to stabilize the output power of the motor in the micro air pump, which in turn leads to difficulty in maintaining a stable output air flow of the micro air pump. When the micro air pump is powered by a battery, there will be a problem of inaccurate output air flow. Therefore, in a portable blood pressure monitor, how to ensure that the cuff pressure stably reaches the preset value has become one of the technical problems to be solved currently. Summary of the Invention

[0004] The main object of the present invention is to provide a micro air pump, aiming to improve the working stability of the micro air pump.

[0005] To achieve the above object, a micro air pump proposed by the present invention is applied to a medical detection instrument, and the medical detection instrument includes a battery. The micro air pump includes:

[0006] A motor;

[0007] A control device;

[0008] A driving circuit, the input end of the driving circuit is electrically connected to the output end of the battery, the controlled end of the driving circuit is electrically connected to the control device, and the output end of the driving circuit is electrically connected to the input end of the motor; the driving circuit is used to adjust the driving power of the motor according to the driving signal output by the control device;

[0009] A voltage detection circuit, the input end of the voltage detection circuit is electrically connected to the output end of the battery, the output end of the voltage detection circuit is electrically connected to the control device, and the voltage detection circuit is used to detect the output voltage of the battery and output a voltage detection signal;

[0010] A leakage detection circuit, the output end of the leakage detection circuit is electrically connected to the control device, and the leakage detection circuit is used to detect the sealing state inside the micro air pump and output a leakage detection signal;

[0011] Wherein, the control device is used to output a corresponding drive signal to the drive circuit according to the voltage detection signal and the leakage detection signal.

[0012] In one embodiment, the control device is used to output a corresponding PWM signal to the drive circuit according to the voltage detection signal and the leakage detection signal;

[0013] Wherein, the voltage value corresponding to the voltage detection signal is inversely proportional to the duty cycle of the PWM signal for driving the motor to work; the sealing state inside the micro air pump corresponding to the leakage detection signal is inversely proportional to the duty cycle of the PWM signal for driving the motor to work.

[0014] In one embodiment, the drive circuit includes:

[0015] A first switch circuit, the first end of the first switch circuit is electrically connected to the negative electrode of the motor, and the controlled end of the first switch circuit is electrically connected to the control device;

[0016] A second switch circuit, the first end of the second switch circuit is electrically connected to the second end of the first switch circuit, the second end of the second switch circuit is electrically connected to the ground terminal, and the controlled end of the second switch circuit is electrically connected to the controlled end of the first switch circuit;

[0017] Wherein, both the first switch circuit and the second switch circuit are used to conduct or disconnect the path between the negative electrode of the motor and the ground terminal.

[0018] In one embodiment, the first switch circuit includes a first switch tube and a first resistor; the second switch circuit includes a second switch tube and a second resistor;

[0019] Wherein, a first end of the first resistor is electrically connected to the control device, and a second end of the first resistor is electrically connected to a controlled end of the first switching tube, a controlled end of the second switching tube, and a first end of the second resistor; a second end of the second resistor is electrically connected to a ground terminal; a first end of the first switching tube is electrically connected to a first end of the second switching tube and a negative electrode of the motor, and a second end of the first switching tube is electrically connected to a second end of the second switching tube.

[0020] In one embodiment, the voltage detection circuit includes a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a first operational amplifier, a first capacitor, and a second capacitor;

[0021] Wherein, a first end of the third resistor is electrically connected to a voltage output terminal of the battery, and a second end of the third resistor is electrically connected to a first end of the fourth resistor and a first end of the fifth resistor; a second end of the fourth resistor is grounded; a second end of the fifth resistor is electrically connected to a first end of the first capacitor and a non-inverting input terminal of the first operational amplifier; a second end of the first capacitor is grounded; an inverting input terminal of the first operational amplifier is electrically connected to an output terminal of the first operational amplifier and a first end of the sixth resistor; a second end of the sixth resistor is electrically connected to a first end of the second capacitor and the control device; a second end of the second capacitor is grounded.

[0022] In one embodiment, the leakage detection circuit includes at least one of a pressure detection circuit, a flow detection circuit, and a current detection circuit.

[0023] In one embodiment, the leakage detection circuit includes:

[0024] A pressure detection circuit, which is disposed in a chamber of the micro air pump, and an input end of the pressure detection circuit is electrically connected to the control device; the pressure detection circuit is configured to output a pressure detection signal;

[0025] A flow detection circuit, which is disposed at a gas output end of the micro air pump, and an output end of the flow detection circuit is electrically connected to the control device; the flow detection circuit is configured to output a flow detection signal;

[0026] A current detection circuit, an input end of the current detection circuit is electrically connected to an output terminal of the battery, and an output end of the current detection circuit is electrically connected to the control device; the current detection circuit is configured to output a current detection signal.

[0027] In one embodiment, the control device is further configured to match a leakage detection signal output by the leakage detection circuit with a preset leakage level, so as to output a corresponding drive signal to the drive circuit.

[0028] In one embodiment, the drive signal is a PWM signal; the control device is further configured to increase the duty cycle of the PWM signal by a first preset ratio under the condition that the leakage detection signal output by the leakage detection circuit matches a first preset leakage level; increase the duty cycle of the PWM signal by a second preset ratio under the condition that the leakage detection signal output by the leakage detection circuit matches a second preset leakage level; and stop outputting the drive signal to the drive circuit under the condition that the leakage detection signal output by the leakage detection circuit matches a third preset leakage level.

[0029] Wherein, the first preset leakage level is that under normal operating conditions of the micro air pump, the air pressure value inside the micro air pump is less than a first preset air pressure and greater than or equal to a second preset air pressure; the second preset leakage level is that under normal operating conditions of the micro air pump, the air pressure value inside the micro air pump is less than the second preset air pressure and greater than or equal to a third preset air pressure; the third preset leakage level is that under normal operating conditions of the micro air pump, the air pressure value inside the micro air pump is less than the third preset air pressure.

[0030] In one embodiment, the control device is further configured to stop outputting the drive signal to the drive circuit when the leakage detection signal output by the leakage detection circuit matches the first preset leakage level under the condition that the voltage value corresponding to the voltage detection signal matches a preset voltage value.

[0031] Wherein, under the condition that the voltage value corresponding to the voltage detection signal matches the preset voltage value, the duty cycle of the PWM signal output by the control device is the maximum value.

[0032] The technical solution of the present invention detects the voltage value output from the battery to the micro air pump in the medical device by using the voltage detection circuit provided in the micro air pump, and then confirms the working state of the battery. The control device controls the drive signal output to the drive circuit by receiving the voltage detection signal output by the voltage detection circuit, and then adjusts the drive power of the motor under the condition that the output voltage of the battery is changing, so that the drive power of the motor is within the preset drive power range. The control device also confirms the sealing state inside the micro air pump through the leakage detection signal output by the leakage detection circuit, and thus outputs a corresponding drive signal to the motor to adjust the drive power of the motor. The control device adjusts the drive power of the motor to make up for the problem of insufficient output gas flow of the micro air pump caused by leakage, thereby improving the working stability of the micro air pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0034] Figure 1 Structural schematic diagram of the micro air pump of the present invention;

[0035] Figure 2 Structural schematic diagram of an embodiment of the micro air pump of the present invention;

[0036] Figure 3 Circuit structural schematic diagram of an embodiment of the micro air pump of the present invention;

[0037] Figure 4 Circuit structural schematic diagram of another embodiment of the micro air pump of the present invention;

[0038] Figure 5 Structural schematic diagram of another embodiment of the micro air pump of the present invention.

[0039] Explanation of the reference numerals in the drawings:

[0040] 10. Control device; 20. Driving circuit; 21. First switch circuit; 22. Second switch circuit; 30. Voltage detection circuit; 40. Leakage detection circuit; 41. Pressure detection circuit; 42. Flow detection circuit; 43. Current detection circuit.

[0041] The realization, functional features and advantages of the object of the present invention will be further described with reference to the embodiments and the accompanying drawings. Specific embodiments

[0042] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0043] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present invention are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the drawings). If the specific posture changes, the directional indications will also change accordingly.

[0044] In addition, the descriptions involving "first", "second", etc. in the present invention are for descriptive purposes only, and should not be construed as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions between various embodiments may be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions 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 invention.

[0045] A portable blood pressure monitor is mainly used to measure the arterial blood pressure of the human body, which is one of the important indicators for evaluating cardiovascular health. When using a portable blood pressure monitor, a micro air pump inflates the cuff until the pressure in the cuff is sufficient to temporarily block arterial blood flow. Then, the cuff gradually deflates, and at the same time, the built-in pressure sensor monitors the change in the pressure in the cuff. As the cuff pressure drops, blood begins to flow again, and the pulsation signal generated at this time is analyzed to determine the systolic and diastolic blood pressure values. If there is a leak in the micro air pump or the amount of air inflated into the cuff fails to reach the preset value, this will directly affect the working stability and efficiency of the portable blood pressure monitor. When there is a leak in the micro air pump or the amount of air inflated into the cuff fails to reach the preset value, the cuff cannot maintain the required stable pressure, resulting in too rapid a pressure drop or failure to reach the required maximum pressure during the measurement process, which will lead to inaccurate blood pressure readings. In addition, the leak in the micro air pump will also cause the portable blood pressure monitor to take a longer time to reach the required maximum pressure.

[0046] In addition, a portable blood pressure monitor usually uses a battery to supply power to the motor in the micro air pump to meet the convenience requirement. However, since the output voltage of the battery changes with the battery level, it is difficult to stabilize the output power of the motor in the micro air pump, which in turn leads to difficulty in maintaining a stable output air flow of the micro air pump. As a result, when the micro air pump is powered by a battery, there will be a problem of inaccurate output air flow. Therefore, in a portable blood pressure monitor, how to ensure that the cuff pressure stably reaches the preset value has become one of the technical problems to be solved currently.

[0047] Therefore, referring to Figures 1 to 5 , the technical solution of the present application proposes a micro air pump applied to a medical detection device, the medical detection device including a battery, and the micro air pump includes:

[0048] A motor;

[0049] A control device 10;

[0050] A drive circuit 20, the input end of the drive circuit 20 is electrically connected to the output end of the battery, the controlled end of the drive circuit 20 is electrically connected to the control device 10, and the output end of the drive circuit 20 is electrically connected to the input end of the motor; the drive circuit 20 is used to adjust the drive power of the motor according to the drive signal output by the control device 10;

[0051] A voltage detection circuit 30, the input end of the voltage detection circuit 30 is electrically connected to the output end of the battery, the output end of the voltage detection circuit 30 is electrically connected to the control device 10, and the voltage detection circuit 30 is used to detect the output voltage of the battery and output a voltage detection signal;

[0052] A leakage detection circuit 40, the output end of the leakage detection circuit 40 is electrically connected to the control device 10, and the leakage detection circuit 40 is used to detect the sealing state inside the micro air pump and output a leakage detection signal;

[0053] Wherein, the control device 10 is used to output a corresponding drive signal to the drive circuit 20 according to the voltage detection signal and the leakage detection signal.

[0054] In this embodiment, medical detection instruments using a micro air pump include a blood pressure monitor, a spirometer, etc. Among them, in a blood pressure monitor, the micro air pump is used to inflate and deflate the cuff to measure the blood pressure of a patient; in a spirometer, the micro air pump can help generate a stable air flow for accurate measurement by the spirometer.

[0055] In this embodiment, the type of motor used in the micro air pump mainly depends on application requirements, such as power, efficiency, volume limitation, noise requirements, etc. Specifically, a brushless DC motor, a stepper motor, a brushed DC motor, a piezoelectric motor, etc. can be selected. The micro air pump drives its internal mechanical structure through the motor to realize the inhalation and discharge of air, thereby completing the functions of inflation or air extraction. Therefore, the control device 10 can indirectly control the inhalation and discharge of air in the micro air pump by controlling the drive of the motor.

[0056] In this embodiment, the control device 10 can be implemented by a main controller, such as a DSP (Digital Signal Process, digital signal processing chip), an FPGA (Field Programmable Gate Array, programmable logic gate array chip), an MCU (Microcontroller Unit, micro control unit), an SOC (System On Chip, system-level chip), etc. Among them, the control device 10 receives the voltage detection signal and the leakage detection signal, so as to confirm the working state of the battery and the sealing state inside the micro air pump under the condition that the micro air pump is working normally, and then outputs a corresponding drive signal to the drive circuit 20, so that the drive circuit 20 drives the motor to work at a corresponding speed. It can be understood that when the micro air pump works continuously, the battery power will gradually decrease, and the output voltage of the battery will gradually decrease due to the decrease in power. If the control device 10 always outputs the same drive signal to the micro air pump, the speed of the motor will gradually decrease, and then the gas volume output by the micro air pump at an instant will gradually decrease. Therefore, the control device 10 needs to make corresponding adjustments to the drive signal output to the drive circuit 20 to ensure the stability of the gas volume output by the micro air pump at an instant. Further, under the condition that the micro air pump has different degrees of leakage, the technical effect of the control device 10 outputting a corresponding drive signal to the drive circuit 20 according to the voltage detection signal will be reduced due to the leakage inside the micro air pump, that is, under the condition that the micro air pump has different degrees of leakage, the gas volume output by the micro air pump at an instant will still fluctuate because some gas overflows after the gas output end of the micro air pump. Therefore, the control device 10 also needs to confirm the leakage state inside the micro air pump according to the leakage detection signal output by the leakage detection circuit 40, so as to further adjust the drive signal output to the drive circuit 20 to make the gas volume output by the micro air pump at an instant more stable.

[0057] In this embodiment, the selection of the drive circuit 20 of the drive motor depends on the motor type and its application scenario. For example, when the motor is selected as a DC brushed motor, a DC brushed motor can be used; when the motor is selected as a DC brushless motor, a three-phase inverter drive circuit 20 can be used; when the motor is a piezoelectric motor, a high-voltage drive circuit 20 can be used to implement it. Among them, the input end of the drive circuit 20 is electrically connected to the output end of the battery, the controlled end of the drive circuit 20 is electrically connected to the control device 10, and the output end of the drive circuit 20 is electrically connected to the motor. The drive circuit 20 adjusts the drive power output to the motor by receiving the drive signal output by the control device 10. Further, the drive circuit 20 can be implemented by multiple switch circuits, and the on and off of the switch circuits are controlled by the PWM signal output by the control device 10. The ratio of the on and off of the switch circuits in a cycle is controlled by the duty cycle of the PWM signal. Specifically, the drive circuit 20 includes: a first switch circuit 21, the first end of the first switch circuit 21 is electrically connected to the negative electrode of the motor, and the controlled end of the first switch circuit 21 is electrically connected to the main control circuit; a second switch circuit 22, the first end of the second switch circuit 22 is electrically connected to the second end of the first switch circuit 21, the second end of the second switch circuit 22 is electrically connected to the ground terminal, and the controlled end of the second switch circuit 22 is electrically connected to the controlled end of the first switch circuit 21; wherein, both the first switch circuit 21 and the second switch circuit 22 are used to conduct or disconnect the path between the negative electrode of the motor and the ground terminal. Further, the first switch circuit 21 includes a first switch tube Q1 and a first resistor R1; the second switch circuit 22 includes a second switch tube Q2 and a second resistor R2; wherein, the first end of the first resistor R1 is electrically connected to the main control circuit, and the second end of the first resistor R1 is electrically connected to the controlled end of the first switch tube Q1, the controlled end of the second switch tube Q2, and the first end of the second resistor R2; the second end of the second resistor R2 is electrically connected to the ground terminal; the first end of the first switch tube Q1 is electrically connected to the first end of the second switch tube Q2 and the negative electrode of the motor, and the second end of the first switch tube Q1 is electrically connected to the second end of the second switch tube Q2. The switch tube can be implemented by, for example, a MOS tube, an IGBT tube, a thyristor, a triode, a power tube, etc. It can be understood that the first ends of the first switch tube Q1 and the second switch tube Q2 are electrically connected to the negative electrode of the motor, and the second ends of the first switch tube Q1 and the second switch tube Q2 are electrically connected to the ground terminal. Among them, the first switch tube Q1 and the second switch tube Q2 are arranged in parallel to achieve the technical effect of shunt conduction. In addition, by setting the first switch tube Q1 and the second switch tube Q2, the working stability of the switch tube is effectively improved, and the possibility of the switch tube being damaged is greatly reduced.The controlled terminals of the first switching transistor Q1 and the second switching transistor Q2 are turned on or off through the driving signals output by the receiving control device 10 to conduct or disconnect the path between the negative electrode of the motor and the ground terminal, thereby realizing the control of the motor power supply path and further realizing the regulation of the motor driving power.

[0058] In this embodiment, the voltage detection circuit 30 can be implemented by a voltage division circuit, a differential amplifier circuit, a comparator circuit, etc. Among them, the voltage division circuit divides the voltage by connecting two or more resistors in series, reducing the voltage to be measured proportionally to the input range suitable for a measuring instrument (such as an ADC). For example, when using two resistors in series and the measurement point is between the two resistors, the voltage drop calculated by Ohm's law is a part of the voltage to be measured. The differential amplifier circuit is suitable for accurately measuring the potential difference between two points in a circuit. Especially when there is a common-mode voltage interference, the differential amplifier circuit is very useful. The differential amplifier has two input terminals, which are respectively connected to the positive and negative terminals of the voltage to be measured, and can effectively suppress the common-mode noise, amplify the differential-mode signal, and improve the measurement accuracy. By adopting the voltage detection circuit 30, the output voltage of the battery can be effectively detected, and then the control device 10 outputs an accurate drive signal to the drive circuit 20, effectively controlling the rotational speed of the motor, so as to realize the control of the output gas of the micro air pump. Specifically, the voltage detection circuit 30 includes a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a first operational amplifier, a first capacitor C1, and a second capacitor C2; among them, the first terminal of the third resistor R3 is electrically connected to the voltage output terminal of the battery, and the second terminal of the third resistor R3 is electrically connected to the first terminal of the fourth resistor R4 and the first terminal of the fifth resistor R5; the second terminal of the fourth resistor R4 is grounded; the second terminal of the fifth resistor R5 is electrically connected to the first terminal of the first capacitor C1 and the non-inverting input terminal of the first operational amplifier; the second terminal of the first capacitor C1 is grounded; the inverting input terminal of the first operational amplifier is electrically connected to the output terminal of the first operational amplifier and the first terminal of the sixth resistor R6; the second terminal of the sixth resistor R6 is electrically connected to the first terminal of the second capacitor C2 and the control device 10; the second terminal of the second capacitor C2 is grounded. The input voltage is divided by the third resistor R3 and then connected in parallel with the fifth resistor R5 to facilitate adjusting the magnitude of the input voltage to adapt to the input range of the operational amplifier. The adjusted input voltage enters the non-inverting input terminal of the first operational amplifier through the fifth resistor R5. Among them, the first operational amplifier is a non-inverting operational amplifier, and its output voltage is in phase with and equal to the input voltage. Therefore, the output voltage of the operational amplifier is in phase with and equal to the input voltage. After the output voltage is filtered by the second filter, it is output to the control device 10. The function of the second capacitor C2 is to filter out high-frequency noise and ensure the accuracy of the voltage detection signal obtained by the control device 10. The sixth resistor R6 and the second capacitor C2 form an RC low-pass filter, which can further filter out high-frequency noise and improve the signal quality. The fifth resistor R5 and the second capacitor C2 also form an RC time constant, which determines the cut-off frequency of the filter. The lower the cut-off frequency, the better the filtering effect, but the response speed will also slow down. The values of the fifth resistor R5 and the second capacitor C2 can be adjusted according to actual needs to achieve the best filtering effect and response speed.The fourth resistor R4 and the first capacitor C1 form an RC filter for suppressing power supply noise. Power supply noise may affect the performance of the operational amplifier, so it needs to be suppressed. The values of the fourth resistor R4 and the first capacitor C1 can also be adjusted according to actual needs to achieve the best filtering effect and response speed.

[0059] In this embodiment, the leak detection circuit 40 can be implemented by at least one of the pressure detection circuit 41, the flow detection circuit 42, and the current detection circuit 43. The leak detection circuit 40 is electrically connected to the control device 10 and outputs a corresponding leak detection signal to the control device 10 under the condition that the micro air pump is working normally. The control device 10 obtains the leak detection signal and matches it with a preset leak level. Among them, the preset leak level will be set according to the air pressure value inside the micro air pump under normal working conditions and good airtight conditions. For example, under normal working conditions of the micro air pump and good airtight conditions, the air pressure value inside it is 100%. When the micro air pump drives the motor to rotate with the same driving power, the internal air pressure value corresponding to the detection signal output by the leak detection circuit 40 is 90%, and when there is a corresponding internal air pressure value of 90% in the preset leak level, the control device 10 can confirm the sealing state inside the micro air pump through the matching relationship between the leak detection signal of the leak detection circuit 40 and the preset leak level.

[0060] By using the voltage detection circuit 30 provided in the micro air pump to detect the voltage value output from the battery to the micro air pump in the medical device, the working state of the battery is further confirmed. The control device 10 controls the driving signal output to the driving circuit 20 by receiving the voltage detection signal output by the voltage detection circuit 30, and then adjusts the driving power of the motor under the condition that the output voltage of the battery is changing, so that the driving power of the motor is within the preset driving power range. The control device 10 also confirms the sealing state inside the micro air pump through the leak detection signal output by the leak detection circuit 40, and then outputs a corresponding driving signal to the motor to adjust the driving power of the motor. The control device 10 adjusts the driving power of the motor to make up for the problem of insufficient output gas flow of the micro air pump due to leakage, thereby improving the working stability of the micro air pump.

[0061] In an embodiment of the present invention, the control device 10 is configured to output a corresponding PWM signal to the driving circuit 20 according to the voltage detection signal and the leak detection signal;

[0062] Wherein, the voltage value corresponding to the voltage detection signal is inversely proportional to the duty cycle of the PWM signal for driving the motor to work; the sealing state inside the micro air pump corresponding to the leak detection signal is inversely proportional to the duty cycle of the PWM signal for driving the motor to work.

[0063] It can be understood that the output voltage of the battery will directly affect the working power of the motor in the micro air pump. Therefore, a preset correspondence relationship is built into the control device 10, that is, there is a correspondence relationship between the output voltage of the battery and the driving signal for driving the motor to work. Further, the driving of the motor can be achieved by means such as PWM signal control, direct voltage change control, resistance control, current chopping control, etc. Taking the driving signal of the motor as a PWM signal as an example, the adjustment of the motor driving can be achieved by changing the duty cycle and output frequency of the PWM signal. Among them, it is not difficult to understand that as the micro air pump continues to work, the output voltage of the battery will gradually decrease, that is, the power supply voltage of the motor will gradually decrease. And increasing the duty cycle of the PWM signal means that within a PWM cycle, the proportion of the high level increases. Although the voltage of a single pulse is still the output voltage of the battery after reduction, due to the longer high level time, the effective average voltage passing through the motor will increase. In this way, the average input power of the motor can be increased without significantly increasing the instantaneous current, thereby maintaining the rotational speed of the motor. Among them, the voltage value corresponding to the voltage detection signal is inversely proportional to the duty cycle of the PWM signal for driving the motor to work, that is, the larger the voltage value corresponding to the voltage detection signal, the smaller the duty cycle of the PWM signal for driving the motor to work; the smaller the voltage value corresponding to the voltage detection signal, the larger the duty cycle of the PWM signal for driving the motor to work. In addition, to ensure that the gas volume output by the micro air pump at any instant is in a stable state, it is necessary to adjust the driving signal output to the driving circuit 20 according to the sealing state inside the micro air pump, so that the driving power of the motor can be correspondingly adjusted. It can be understood that to ensure that the gas volume output by the micro air pump at any instant is stable, when there is a low leakage situation inside the micro air pump, the control device 10 will obtain a leakage detection signal according to the leakage detection circuit 40 and confirm this leakage situation, so as to correspondingly increase the duty cycle of the PWM signal output to the driving circuit 20, so that the rotational speed of the motor can be increased, thereby making up for the gas volume leaked out due to the internal leakage of the micro air pump. Therefore, the worse the sealing state inside the micro air pump corresponding to the leakage detection signal, the larger the duty cycle of the PWM signal for driving the motor to work; the better the sealing state inside the micro air pump corresponding to the leakage detection signal, the smaller the duty cycle of the PWM signal for driving the motor to work. Among them, the sealing state inside the micro air pump can be confirmed by a preset leakage level in the control device 10.

[0064] Reference Figure 5 , in an embodiment of the present invention, the leakage detection circuit 40 includes at least one of a pressure detection circuit 41, a flow detection circuit 42, and a current detection circuit 43.

[0065] In this embodiment, the pressure detection circuit 41 can be implemented using a pressure sensor, such as a piezoresistive pressure sensor, a capacitive pressure sensor, etc. The flow detection circuit 42 can be implemented using a turbine flowmeter, an ultrasonic flowmeter, etc. The current detection circuit 43 can be implemented using a shunt resistor, a Hall effect sensor, a current transformer, etc.

[0066] Furthermore, the leakage detection circuit includes:

[0067] A pressure detection circuit 41, which is disposed in the chamber of the micro air pump. The input end of the pressure detection circuit 41 is electrically connected to the control device 10; the pressure detection circuit 41 is used to output a pressure detection signal.

[0068] A flow detection circuit 42, which is disposed at the gas output end of the micro air pump. The output end of the flow detection circuit 42 is electrically connected to the control device 10; the flow detection circuit 42 is used to output a flow detection signal.

[0069] A current detection circuit 43, the input end of which is electrically connected to the output end of the battery, and the output end of the current detection circuit 43 is electrically connected to the control device 10; the current detection circuit 43 is used to output a current detection signal.

[0070] Among them, when the leakage detection circuit 40 uses the pressure detection circuit 41 and there is a leakage inside the micro air pump, the internal pressure will drop. Therefore, the control device 10 can confirm the internal sealing state of the micro air pump during normal operation through the pressure detection signal output by the pressure detection circuit 41 disposed in the chamber of the micro air pump. When the leakage detection circuit 40 uses the flow detection circuit 42 and the flow detection circuit 42 is disposed at the gas output end, if the actual flow rate is lower than the expected value and other factors (such as blockage of the inlet filter) have been excluded, the control device 10 can confirm the existence of leakage of the micro air pump through the flow detection signal. When the leakage detection circuit 40 uses the current detection circuit 43, for a motor-driven micro air pump, the working current of the motor is directly related to the load. For example, during liquid transportation, if a leakage occurs and the load decreases, the motor current will also decrease accordingly. Therefore, by monitoring the change in the motor current, it is possible to indirectly determine whether a leakage has occurred.

[0071] In an embodiment of the present invention, the control device 10 is further configured to match the leakage detection signal output by the leakage detection circuit 40 with a preset leakage level, so as to output a corresponding drive signal to the drive circuit 20.

[0072] Furthermore, the drive signal is a PWM signal; the control device 10 is further configured to increase the duty cycle of the PWM signal by a first preset ratio under the condition that the leakage detection signal output by the leakage detection circuit 40 matches the first preset leakage level; increase the duty cycle of the PWM signal by a second preset ratio under the condition that the leakage detection signal output by the leakage detection circuit 40 matches the second preset leakage level; and stop outputting the drive signal to the drive circuit 20 under the condition that the leakage detection signal output by the leakage detection circuit 40 matches the third preset leakage level.

[0073] Wherein, the first preset leakage level is that when the micro air pump is under normal working conditions, the air pressure value in the micro air pump is less than the first preset air pressure and greater than or equal to the second preset air pressure; the second preset leakage level is that when the micro air pump is under normal working conditions, the air pressure value in the micro air pump is less than the second preset air pressure and greater than or equal to the third preset air pressure; the third preset leakage level is that when the micro air pump is under normal working conditions, the air pressure value in the micro air pump is less than the third preset air pressure.

[0074] As can be seen from the above, the sealing state inside the miniature air pump corresponding to the leakage detection signal is inversely proportional to the duty cycle of the PWM signal for the operation of the drive motor. Therefore, after the control device 10 receives the leakage detection signal output by the leakage detection circuit 40, it will further process the leakage detection signal and confirm the current leakage state of the miniature air pump by matching the leakage detection signal with a preset leakage level. Among them, it is the normal pressure value obtained through pressure detection under the normal operating conditions of the miniature air pump. R & D personnel can use this normal pressure value as a reference standard to set corresponding first preset air pressure, second preset air pressure, and third preset air pressure, and set corresponding preset leakage levels according to the first preset air pressure, second preset air pressure, and third preset air pressure. It can be understood that the first preset leakage level, second preset leakage level, and third preset leakage level all correspond to different air pressure range values. The control device 10 can correspond the leakage detection signal output by the leakage detection circuit 40 with the actual air pressure value in the miniature air pump according to the corresponding mapping relationship, so as to achieve the matching of the leakage detection signal with the preset leakage level. Under the condition that the leakage detection signal output by the leakage detection circuit 40 matches the first preset leakage level, the duty cycle of the PWM signal is increased by a first preset ratio. At this time, the rotational speed of the motor will also increase correspondingly, so as to make up for the gas volume overflowing due to internal leakage of the miniature air pump, and further ensure the stability of the gas output of the miniature gas. Under the condition that the leakage detection signal output by the leakage detection circuit 40 matches the third preset leakage level, the control device 10 will stop outputting the drive signal to the drive circuit 20 and output a corresponding control signal to the prompt circuit, so that the prompt circuit outputs a corresponding prompt signal. It can be understood that under the condition that the leakage detection signal output by the leakage detection circuit 40 matches the third preset leakage level, the control device 10 will confirm that the sealing state inside the miniature air pump is poor and the gas output of the miniature air pump cannot be stabilized by adjusting the duty cycle of the PWM signal.

[0075] Optionally, the control device 10 is further configured to stop outputting the drive signal to the drive circuit 20 when the leakage detection signal output by the leakage detection circuit 40 matches the first preset leakage level under the condition that the voltage value corresponding to the voltage detection signal matches the preset voltage value;

[0076] Among them, under the condition that the voltage value corresponding to the voltage detection signal matches the preset voltage value, the duty cycle of the PWM signal output by the control device 10 is the maximum value.

[0077] In this embodiment, the continuous operation of the micro air pump will cause the battery power to decrease, and the decrease in battery power will cause the output voltage of the battery to decrease. Therefore, the control device 10 will detect the output voltage of the battery through the voltage detection circuit 30 and output a corresponding voltage detection signal. The control device 10 obtains this voltage detection signal to confirm the output voltage of the battery, and adjusts the duty cycle of the PWM signal output to the drive circuit 20 according to the adjustment relationship between the voltage value corresponding to the preset voltage detection signal and the duty cycle of the PWM signal. It can be understood that when the output voltage of the battery drops to the preset voltage value, the control device 10 will control the duty cycle of the output PWM signal to be the maximum value. At this time, when the leakage detection circuit 40 outputs a leakage detection signal to the control device 10, after the control device 10 confirms that there is a leakage inside the micro air pump, it will stop outputting a drive signal to the drive circuit 20 and output a corresponding control signal to the prompt circuit, so that the prompt circuit outputs a corresponding prompt signal. Through this prompt signal, the user can confirm that there is a leakage problem with the micro air pump currently, and the battery power is at a relatively low value, and the gas cannot be stably output by self-adjustment.

[0078] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention. Any equivalent structural transformation made by using the content of the specification and drawings of the present invention under the inventive concept of the present invention, or direct / indirect application in other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A micro air pump, used in medical testing equipment, characterized in that: The medical detection device comprises a battery, and the micro air pump comprises: Motor; Control devices; A drive circuit, wherein the input end of the drive circuit is electrically connected to the output end of the battery, the controlled end of the drive circuit is electrically connected to the control device, and the output end of the drive circuit is electrically connected to the input end of the motor; the drive circuit is used to adjust the drive power of the motor according to the drive signal output by the control device; a voltage detection circuit, wherein an input end of the voltage detection circuit is electrically connected to an output end of the battery, an output end of the voltage detection circuit is electrically connected to the control device, and the voltage detection circuit is used to detect the output voltage of the battery and output a voltage detection signal; A leakage detection circuit, wherein an output end of the leakage detection circuit is electrically connected to the control device, and the leakage detection circuit is used to detect the sealing state inside the micro air pump and output a leakage detection signal; Wherein, the control device is used to output a corresponding driving signal to the driving circuit according to the voltage detection signal and the leakage detection signal.

2. The micro air pump according to claim 1, characterized in that: The control device is used to output a corresponding PWM signal to the drive circuit according to the voltage detection signal and the leakage detection signal; Among them, the voltage value corresponding to the voltage detection signal is inversely proportional to the duty cycle of the PWM signal that drives the motor to work; the sealing state inside the micro air pump corresponding to the leakage detection signal is inversely proportional to the duty cycle of the PWM signal that drives the motor to work.

3. The micro air pump according to claim 1, characterized in that: The driving circuit comprises: a first switch circuit, wherein a first end of the first switch circuit is electrically connected to a negative electrode of the motor, and a controlled end of the first switch circuit is electrically connected to the control device; a second switch circuit, wherein a first end of the second switch circuit is electrically connected to a second end of the first switch circuit, a second end of the second switch circuit is electrically connected to a ground end, and a controlled end of the second switch circuit is electrically connected to a controlled end of the first switch circuit; The first switch circuit and the second switch circuit are both used to open or close the path between the negative pole of the motor and the ground terminal.

4. The micro air pump according to claim 3, characterized in that: The first switch circuit includes a first switch tube and a first resistor; the second switch circuit includes a second switch tube and a second resistor; Among them, the first end of the first resistor is electrically connected to the control device, the second end of the first resistor is electrically connected to the controlled end of the first switch tube, the controlled end of the second switch tube, and the first end of the second resistor; the second end of the second resistor is electrically connected to the ground end; the first end of the first switch tube is electrically connected to the first end of the second switch tube and the negative pole of the motor, and the second end of the first switch tube is electrically connected to the second end of the second switch tube.

5. The micro air pump according to claim 1, characterized in that: The voltage detection circuit includes a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a first operational amplifier, a first capacitor, and a second capacitor; Among them, the first end of the third resistor is electrically connected to the voltage output end of the battery, the second end of the third resistor is electrically connected to the first end of the fourth resistor and the first end of the fifth resistor; the second end of the fourth resistor is grounded; the second end of the fifth resistor is electrically connected to the first end of the first capacitor and the non-inverting input end of the first operational amplifier; the second end of the first capacitor is grounded; the inverting input end of the first operational amplifier is electrically connected to the output end of the first operational amplifier and the first end of the sixth resistor; the second end of the sixth resistor is electrically connected to the first end of the second capacitor and the control device; the second end of the second capacitor is grounded.

6. The micro air pump according to claim 1, characterized in that: The leakage detection circuit includes at least one of a pressure detection circuit, a flow detection circuit, and a current detection circuit.

7. The micro air pump according to claim 6, characterized in that: The leakage detection circuit comprises: A pressure detection circuit, wherein the pressure detection circuit is disposed in the chamber of the micro air pump, and an input end of the pressure detection circuit is electrically connected to the control device; the pressure detection circuit is used to output a pressure detection signal; A flow detection circuit, wherein the flow detection circuit is arranged at the gas output end of the micro air pump, and the output end of the flow detection circuit is electrically connected to the control device; the flow detection circuit is used to output a flow detection signal; A current detection circuit, wherein the input end of the current detection circuit is electrically connected to the output end of the battery, and the output end of the current detection circuit is electrically connected to the control device; the current detection circuit is used to output a current detection signal.

8. The micro air pump according to claim 1, characterized in that: The control device is also used to match the leakage detection signal output by the leakage detection circuit with a preset leakage level to output a corresponding driving signal to the driving circuit.

9. The micro air pump according to claim 8, characterized in that: The driving signal is a PWM signal; the control device is further used to increase the duty cycle of the PWM signal according to a first preset ratio under the condition that the leakage detection signal output by the leakage detection circuit matches the first preset leakage level; increase the duty cycle of the PWM signal according to a second preset ratio under the condition that the leakage detection signal output by the leakage detection circuit matches the second preset leakage level; and stop outputting the driving signal to the driving circuit under the condition that the leakage detection signal output by the leakage detection circuit matches the third preset leakage level; Among them, the first preset leakage level means that under normal working conditions of the micro air pump, the air pressure value inside the micro air pump is less than the first preset air pressure and is greater than or equal to the second preset air pressure; the second preset leakage level means that under normal working conditions of the micro air pump, the air pressure value inside the micro air pump is less than the second preset air pressure and is greater than or equal to the third preset air pressure; the third preset leakage level means that under normal working conditions of the micro air pump, the air pressure value inside the micro air pump is less than the third preset air pressure.

10. The micro air pump according to claim 9, characterized in that: The control device is also used to stop outputting the drive signal to the drive circuit when the leakage detection signal output by the leakage detection circuit matches the first preset leakage level under the condition that the voltage value corresponding to the voltage detection signal matches the preset voltage value; Wherein, under the condition that the voltage value corresponding to the voltage detection signal matches the preset voltage value, the duty cycle of the PWM signal output by the control device is the maximum value.

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