CN210990370U

CN210990370U - Ultrasonic drive circuit and ultrasonic lung function instrument

Info

Publication number: CN210990370U
Application number: CN201920737612.7U
Authority: CN
Inventors: 李坤耀; 周玉民; 田禾燊; 邓英强; 陈建民
Original assignee: Guangzhou Changhu Medical Instrument Co ltd
Current assignee: Guangzhou Changhu Medical Instrument Co ltd
Priority date: 2019-05-21
Filing date: 2019-05-21
Publication date: 2020-07-14
Anticipated expiration: 2029-05-21

Abstract

The utility model discloses an ultrasonic drive circuit and supersound lung function appearance, wherein drive circuit includes the treater, steps up drive module, first transmission receiving module, second transmission receiving module, signal amplification module and for the power module of each module power supply, the treater is connected with drive module, first transmission receiving module, second transmission receiving module and the signal amplification module that steps up respectively, step up drive module and be connected with first transmission receiving module and second transmission receiving module respectively, the signal amplification module is connected with first transmission receiving module and second transmission receiving module respectively. The utility model boosts the voltage provided by the power module into the driving voltage, and drives the first transmitting and receiving module and the second transmitting and receiving module to transmit ultrasonic waves by adopting the driving voltage, thereby greatly reducing the energy consumption of the driving circuit; meanwhile, the volume of the battery can be reduced, so that the volume of the equipment is reduced, and the ultrasonic generator can be widely applied to the technical field of ultrasonic waves.

Description

Ultrasonic drive circuit and ultrasonic lung function instrument

Technical Field

The utility model relates to an ultrasonic wave technical field especially relates to an ultrasonic drive circuit and supersound lung function appearance.

Background

With economic development, environmental pollution is becoming more severe, resulting in more and more people suffering from respiratory diseases. The lung function examination is one of necessary examinations of respiratory system diseases, and the lung function is measured by a lung function instrument, so that the purpose of detecting respiratory system abnormality is achieved. The kit has important guiding significance for early detection of lung and respiratory tract diseases, such as chronic bronchitis, emphysema, bronchial asthma, intermittent lung diseases and the like.

The core technology of the lung function instrument is sensor technology, and the key is a flow sensor. Most current pulmonary function meter flow measurements are made using turbine or differential pressure sensors. The principle of the turbine flowmeter is that the rotation speed of a rotating part (an impeller or a turbine) is directly proportional to the fluid speed to be measured. When the airflow passes through the impeller or the turbine, the impeller type adopts a photoelectric modulation principle, and through a photoelectric effect, the turbine type adopts a magnetoelectric modulation principle, and through the magnetoelectric effect, mechanical rotation signals of the impeller or the turbine are converted into electric signals to be output. Due to factors such as the motion inertia of the impeller, the friction torque between the rotating shaft and the bearing and the like, the precision of the sensor can be influenced. The differential pressure type flow sensor has high linearity, but the traditional differential pressure type flow velocity sensor adopts a metal screen, needs temperature and pressure compensation, is subjected to a plurality of interference factors and needs linear correction. When the flow is big, the pressure difference is also big, and respiratory resistance is also big, thereby steam condenses on it easily moreover and causes velocity of flow measuring error, still needs heating apparatus for avoiding the condensation of steam, nevertheless heats and can make gas expansion and measuring error bigger, and cleaning and disinfecting all need dry the back in addition and just can use.

In order to solve the above problems, it is now proposed to perform measurement using an ultrasonic flow sensor. The principle of the ultrasonic flow sensor is that ultrasonic waves must be transmitted by means of a medium, and the ultrasonic transmission is accelerated along the direction of flow; against the direction of flow, the ultrasound propagation will slow down. Then the time difference is the flow. The ultrasonic gas flow measurement technology has the advantages of high sensitivity (very sensitive to weak airflow), good linearity, accurate test, no influence of parameters such as density, viscosity, humidity, temperature and the like of exhaled gas, good repeatability, good stability, no calibration, small respiratory resistance, easy disinfection and avoidance of cross infection.

However, when the existing ultrasonic flow sensor works, a continuous fixed driving signal needs to be generated, and in such a working mode, more energy needs to be consumed, so that the ultrasonic flow sensor needs to work under the condition of being connected with a mains supply, or a larger battery device needs to be worn on the ultrasonic flow sensor, so that the portability of the ultrasonic lung function instrument cannot be realized.

SUMMERY OF THE UTILITY MODEL

In order to solve the technical problem, the present invention provides an ultrasonic driving circuit and an ultrasonic lung function instrument.

The utility model discloses a first technical scheme who adopts is:

the utility model provides an ultrasonic drive circuit, includes treater, the drive module that steps up, first transmission receiving module, second transmission receiving module, signal amplification module and for the power module of each module power supply, the treater is connected with drive module, first transmission receiving module, second transmission receiving module and the signal amplification module that steps up respectively, the drive module that steps up is connected with first transmission receiving module and second transmission receiving module respectively, the signal amplification module is connected with first transmission receiving module and second transmission receiving module respectively.

Further, the first transmitting and receiving module comprises a first ultrasonic head, a first resistor, a second resistor, a first NMOS (N-channel metal oxide semiconductor) tube and a first capacitor;

the positive pole of first ultrasonic head is connected with the one end of first resistance, the one end of second resistance and the one end of first electric capacity respectively, the other end of first resistance is connected to driving voltage, the other end of second resistance is connected with the drain electrode of first NMOS pipe, the grid and the treater of first NMOS pipe are connected, the other end and the signal amplification module of first electric capacity are connected, the negative pole of first ultrasonic head and the source electrode of first NMOS pipe all ground connection.

The signal amplification module is connected with the electronic switch chip through the shielding circuit, and the processor is respectively connected with the signal shielding circuit and the electronic switch chip.

Further, the signal shielding circuit comprises a third resistor, a fourth resistor, a second NMOS transistor, a third NMOS transistor, a second capacitor and a third capacitor;

one end of the third resistor is connected with the first output end of the signal amplification module, the other end of the third resistor is respectively connected with the drain electrode of the second NMOS tube and one end of the second capacitor, and the other end of the second capacitor is connected with the first input end of the electronic switch chip;

one end of the fourth resistor is connected with the second output end of the signal amplification module, the other end of the fourth resistor is respectively connected with the drain electrode of the third NMOS tube and one end of the third capacitor, and the other end of the third capacitor is connected with the second input end of the electronic switch chip;

the processor is respectively connected with the grid electrode of the second NMOS tube and the grid electrode of the third NMOS tube, and the source electrode of the second NMOS tube and the source electrode of the third NMOS tube are both grounded.

Furthermore, a secondary signal amplification module is also arranged at the output end of the electronic switch chip.

Further, the boost driving module comprises a fifth resistor, a sixth resistor, a fourth capacitor, a fifth capacitor, an inductor, a fourth NMOS transistor, a diode and a sixth capacitor;

one end of the inductor is connected with the power module, one end of the fourth capacitor and one end of the fifth capacitor respectively, the other end of the inductor is connected with the drain electrode of the fourth NMOS tube and the anode of the diode respectively, the cathode of the diode is grounded through the sixth capacitor and obtains driving voltage from the cathode of the diode, the cathode of the diode is grounded through the fifth resistor and the sixth resistor in sequence and obtains voltage from the connecting point of the fifth resistor and the sixth resistor to be fed back to the processor, the grid electrode of the fourth NMOS tube is connected to the processor, and the source electrode of the fourth NMOS tube, the other end of the fourth capacitor and the other end of the fifth capacitor are grounded.

The utility model discloses the second technical scheme who adopts is:

an ultrasonic lung function instrument comprises an air blowing pipe and an ultrasonic driving circuit, wherein the ultrasonic driving circuit adopts the ultrasonic driving circuit.

Further, still include wireless communication module, wireless communication module is connected with ultrasonic drive circuit.

The utility model has the advantages that: the utility model provides an ultrasonic drive circuit, through the voltage boost that provides power module for drive voltage to adopt drive voltage drive first transmission receiving module and second transmission receiving module transmission ultrasonic wave, need not to sample the drive signal of fixed frequency and drive, greatly reduce drive circuit's energy consumption, realize driving more energy-conservingly; meanwhile, the size of the battery can be reduced, and a large driving element is not needed, so that the size of the equipment is reduced, and the equipment is more portable.

Drawings

Fig. 1 is a block diagram of an ultrasonic driving circuit according to the present invention;

FIG. 2 is an electronic circuit diagram of a first transceiver module in an embodiment;

FIG. 3 is an electrical circuit diagram of a shielding circuit and an electronic switch chip in a particular embodiment;

FIG. 4 is an electronic circuit diagram of a boost driver module in an exemplary embodiment;

FIG. 5 is an electronic circuit diagram of a power module in an exemplary embodiment;

FIG. 6 is a schematic illustration of the calculated flow in an exemplary embodiment.

Detailed Description

As shown in fig. 1, this embodiment provides an ultrasonic driving circuit, which includes a processor, a boost driving module, a first transmit-receive module, a second transmit-receive module, a signal amplification module, and a power module for supplying power to each module, where the processor is connected to the boost driving module, the first transmit-receive module, the second transmit-receive module, and the signal amplification module, the boost driving module is connected to the first transmit-receive module and the second transmit-receive module, and the signal amplification module is connected to the first transmit-receive module and the second transmit-receive module, respectively.

The current ultrasonic driving is to generate a continuous fixed driving signal to drive the ultrasonic head by driving, for example, continuously generating 10 square waves of 200KHz, and the square waves enable the ultrasonic head to emit a waveform with a fixed frequency, such driving signal needs to output current, and thus needs to consume more energy. The driving circuit provided in this embodiment boosts the voltage provided by the power module to a driving voltage through the boost driving module, specifically, boosts the 5v voltage provided by the power module to a 208v voltage, and the driving voltage is always loaded on the ultrasonic head, and at this time, the ultrasonic head is similar to a capacitor and always loads a voltage, but does not consume energy, and the first transmitting and receiving module and the second transmitting and receiving module are provided with ultrasonic heads, and the ultrasonic heads can transmit ultrasonic waves and receive ultrasonic waves. Therefore, the energy consumption of the driving circuit can be reduced, the size of a battery to be worn is reduced, and a large driving component is not required, so that the size of the equipment is reduced, the cost is reduced, and the equipment is more portable.

Referring to fig. 2, further as a preferred embodiment, the first transmitting and receiving module includes a first ultrasonic head P1, a first resistor R1, a second resistor R2, a first NMOS transistor Q1, and a first capacitor C1;

the positive pole of first ultrasonic head P1 is connected with the one end of first resistance R1, the one end of second resistance R2 and the one end of first electric capacity C1 respectively, the other end of first resistance R1 is connected to drive voltage, the other end and the drain electrode of first NMOS pipe Q1 of second resistance R2 are connected, the grid and the treater of first NMOS pipe Q1 are connected, the other end and the signal amplification module of first electric capacity C1 are connected, the negative pole of first ultrasonic head P1 and the source electrode of first NMOS pipe Q1 all ground connection.

When the gas flow rate control device works, the first transmitting and receiving module is arranged at the upstream position where gas flows through, and the second transmitting and receiving module is arranged at the downstream position where gas flows through, namely, the gas flow rate firstly passes through the first transmitting and receiving module and then passes through the second transmitting and receiving module. In this embodiment, the second transceiver module is implemented by using the same circuit as the first transceiver module.

The specific working mode principle is as follows: when the downstream time is tested, namely the time between the first transmitting and receiving module transmitting and the second transmitting and receiving module receiving signals. The gate FireUp of the first NMOS transistor Q1 inputs a high level, the first NMOS transistor Q1 is turned on, the level of the 2-pin of the first ultrasonic probe P1 (hereinafter, referred to as the upstream ultrasonic probe) is pulled to the ground through R2, when the high level of the gate of the first NMOS transistor Q1 returns to the low level, the first NMOS transistor Q1 is turned off, the 2-pin of the upstream ultrasonic probe is connected to the ultrasonic probe driving voltage 208V through R1, the ultrasonic probe generates ultrasonic waves with corresponding frequencies in the process of receiving the high voltage from the low voltage, the frequencies are determined according to the characteristics of the ultrasonic probe, and the ultrasonic probe with 200KHz high voltage resistance is selected in this embodiment. The ultrasonic wave is propagated through the air to reach a downstream ultrasonic head, namely the ultrasonic head of the second transmitting and receiving module, and the ultrasonic wave is isolated by a capacitor (corresponding to the first capacitor C1 of the first transmitting and receiving module) and then sends a signal to a post-stage amplifying circuit for processing.

When the reverse flow time is tested, namely the time between the second transmitting and receiving module transmitting and the first transmitting and receiving module receiving signals. Similarly, the downstream ultrasonic head generates ultrasonic waves with corresponding frequencies in the process of receiving high voltage from low voltage, the ultrasonic waves are propagated through air to reach the upstream ultrasonic head (the first ultrasonic head P1), and the upstream ultrasonic head receives signals, then the signals are isolated by the first capacitor C1, and then the signals are sent to the post-stage amplification circuit for processing.

The traditional driving method is to generate a fixed driving signal, such as a square wave or a sine wave of 200KHz to drive the ultrasonic head, and the waveform frequency generated by the ultrasonic head is the driving frequency, such as 200KHz, but this will generate current and more energy. In the embodiment, the driving mode is to continuously load a voltage on the ultrasonic head, and the voltage is pulled down at the moment of controlling the opening and closing of the NMOS tube, so that the ultrasonic head can resonate to generate a waveform with fixed frequency, namely, ultrasonic waves are emitted. The method can greatly save the electric energy consumed by driving, so that the equipment has the same endurance time, and only needs a battery with smaller capacity, thereby reducing the volume of the equipment.

Specifically, the forward flow time test and the reverse flow time test are alternately switched every 2.5ms (or 5ms, the shorter the time, the higher the precision, and the higher the requirement on the hardware processing speed), the time difference can be obtained by subtracting the forward flow time and the reverse flow time after the test, and then the flow rate value can be obtained by multiplying the time difference by the coefficient.

Referring to fig. 3, as a further preferred embodiment, the system further includes a signal shielding circuit and an electronic switch chip, the signal amplification module is connected to the electronic switch chip through the shielding circuit, and the processor is connected to the signal shielding circuit and the electronic switch chip respectively.

Referring to fig. 3, further as a preferred embodiment, the signal shielding circuit includes a third resistor R3, a fourth resistor R4, a second NMOS transistor Q2, a third NMOS transistor Q3, a second capacitor C2, and a third capacitor C3;

one end of the third resistor R3 is connected to the first output end of the signal amplification module, the other end of the third resistor R3 is connected to the drain of the second NMOS transistor Q2 and one end of the second capacitor C2, respectively, and the other end of the second capacitor C2 is connected to the first input end of the electronic switch chip U1;

one end of the fourth resistor R4 is connected to the second output end of the signal amplification module, the other end of the fourth resistor R4 is connected to the drain of the third NMOS transistor Q3 and one end of the third capacitor C3, respectively, and the other end of the third capacitor C3 is connected to the second input end of the electronic switch chip U1;

the processor is respectively connected with the grid electrode of a second NMOS transistor Q2 and the grid electrode of a third NMOS transistor Q3, and the source electrode of the second NMOS transistor Q2 and the source electrode of the third NMOS transistor Q3 are both grounded.

When the upstream ultrasonic head transmits ultrasonic waves when being driven, an interference signal generated by the upstream ultrasonic head is transmitted to the signal amplification module through the first capacitor, if the interference signal is not processed, the ultrasonic wave signal acquired by the downstream ultrasonic head generates a strong interference signal, and the interference signal and the ultrasonic wave signal acquired by the downstream ultrasonic head are input to the processor together, so that the acquired ultrasonic wave signal can be interfered.

The signal shielding circuit and the electronic switch chip U1 can well shield interference signals, thereby being more beneficial to subsequent calculation processing work and improving the quality of equipment.

Further as a preferred embodiment, a secondary signal amplification module is further disposed at the output end of the electronic switch chip.

And the secondary signal amplification module transmits the amplified signal to a processor for further calculation processing. The second-stage signal amplification module adopts a gain-variable second-stage signal amplification circuit, the signals are subjected to second-stage amplification after passing through an electronic switch, and the ultrasonic signals received by the electronic switch are weaker as the flow speed of the blowing air is higher, so that the gain of the second-stage amplification circuit is adjustable, and when the detected flow speed is higher, the signal amplification factor is larger, the flow speed is slower, and the amplification factor is smaller.

When the initialization is carried out, the gain of the amplifying circuit is slowly adjusted from low to high, the values of the first peak and the second peak are detected by the mode of whether the stopping time is increased by one waveform period or not, and therefore a reasonable gain value is set after the initialization is finished, and the voltage value of the fixed threshold value just falls in the middle of the first peak and the second peak.

Referring to fig. 4, further as a preferred embodiment, the boost driving module includes a fifth resistor R5, a sixth resistor R6, a fourth capacitor C4, a fifth capacitor C5, an inductor L1, a fourth NMOS transistor Q4, a diode D1, and a sixth capacitor C6;

one end of the inductor L1 is connected to the power module, one end of the fourth capacitor C4 and one end of the fifth capacitor C5, the other end of the inductor L1 is connected to the drain of the fourth NMOS transistor Q4 and the anode of the diode D1, the cathode of the diode D1 is grounded through the sixth capacitor C6, the cathode of the diode D1 obtains a driving voltage, the cathode of the diode D1 is grounded through the fifth resistor R5 and the sixth resistor R6 in sequence, the voltage is obtained from the connection point of the fifth resistor R5 and the sixth resistor R6 and fed back to the processor, the gate of the fourth NMOS transistor Q4 is connected to the processor, and the source of the fourth NMOS transistor Q4, the other end of the fourth capacitor C4 and the other end of the fifth capacitor C5 are all grounded.

In the present embodiment, the 5v voltage of the power supply module is boosted to 208v voltage. The fourth capacitor C4 and the fifth capacitor C5 are used for filtering noise in 5v voltage.

The power supply module may be implemented using a circuit as shown in fig. 5.

Example two

The embodiment provides an ultrasonic pulmonary function instrument, which comprises an air blowing pipe and an ultrasonic driving circuit, wherein the ultrasonic driving circuit adopts the ultrasonic driving circuit in the first embodiment.

The present embodiment and the first embodiment have a one-to-one correspondence relationship, and therefore, have functions and advantageous effects corresponding to the first embodiment.

Further preferably, the ultrasonic driving circuit further comprises a wireless communication module, and the wireless communication module is connected with the ultrasonic driving circuit.

The ultrasonic lung function instrument is connected with the intelligent terminal through the wireless communication module, so that a user can check a test result of the ultrasonic lung function instrument by means of a display screen of the intelligent terminal, the display screen does not need to be installed on the ultrasonic lung function instrument, and the size of the ultrasonic lung function instrument is greatly reduced.

The above-mentioned ultrasonic operation principle will be explained in detail with reference to fig. 6.

Referring to fig. 6, the ultrasonic pulmonary function apparatus adopts the basic principle of the time difference method: when the sound wave propagates in the fluid, the sound wave propagation speed in the downstream direction is increased, the sound wave propagation speed in the upstream direction is reduced, and the same propagation distance has different propagation times. The flow velocity is obtained by using the relation between the propagation time difference and the flow velocity of the measured fluid, and the flow velocity multiplied by the sectional area of the pipeline is the flow.

The specific calculation method comprises the following steps: the ultrasonic downstream is transmitted from the upstream ultrasonic transducer to the downstream ultrasonic transducer, and is accelerated by the fluid flow velocity:

L/t21＝C+v*cosθ (1)

the ultrasonic reverse flow is transmitted from the downstream ultrasonic transducer to the upstream ultrasonic transducer, and is slowed down by the flow velocity of the fluid into:

L/t12＝C-v*cosθ (2)

finishing by (1) to (2) to obtain:

v＝L/(2*cosθ)*[(t12-t21)/(t21*t12)](3)

since the measured forward and backward propagation times t12, t21 include the inherent electroacoustic delays г 12, г 21 caused by circuits, cables, transducers, etc. with their influence subtracted, equation (3) can be rewritten as:

v＝L/(2*cosθ)*{[(t12-г12)-(t21-г21)]/[(t21-г21)*(t12-г12)]} (4)

since the circuits of the two ultrasonic waves are substantially identical, г 12 being г 21, and t12 and t21 being of the order of hundreds of us and г 12 and г 21 being of the order of several ns, the effects of г 12 and г 21 can be neglected theoretically.

The actual fluid flow velocity has flow velocity distribution on the pipeline loading surface due to friction and viscosity action of the pipe wall and the fluid inside, the measured flow velocity v of the single-channel ultrasonic flowmeter on the central line is actually the linear average velocity on the inner diameter of the pipeline section, and the measured flow requires the surface average flow velocity vm of the pipeline section, which are not equal. According to the theory of fluid mechanics, when the reynolds number is larger than 4000, the fluid is in a turbulent state, and a dynamic factor K exists in the relationship between the linear average flow velocity and the surface average flow velocity, namely:

Vm＝v/K (5)

the diameter of the pipe is D, so that the instantaneous volume flow can be obtained:

q instant vm pi (D/2)2 v pi (D/2)2/K (6)

Substitute (3) into (6)

Q instantaneously pi x (D/2)2 x L x (1/t21-1/t12)/(2 x cos θ K) (7)

The flow rate Q transient can be obtained only by measuring t21 and t12, and in continuous measurement, the accumulated flow rate Q in any time period can be obtained by only integrating the measured Q transient with time.

Ultrasonic transducers are commonly integrated into a transmitting-receiving type, and transducers integrated into a transmitting-receiving type and a transmitter-receiver type can transmit ultrasonic waves and receive the ultrasonic waves, so that measurement of forward flow and reverse flow is facilitated.

While the preferred embodiments of the present invention have been described, the present invention is not limited to the above embodiments, and those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and such equivalent modifications or substitutions are intended to be included within the scope of the present invention as defined by the appended claims.

Claims

1. The utility model provides an ultrasonic drive circuit, its characterized in that, includes treater, the drive module that steps up, first transmission receiving module, second transmission receiving module, signal amplification module and for the power module of each module power supply, the treater is connected with drive module, first transmission receiving module, second transmission receiving module and the signal amplification module that steps up respectively, the drive module that steps up is connected with first transmission receiving module and second transmission receiving module respectively, the signal amplification module is connected with first transmission receiving module and second transmission receiving module respectively.

2. The ultrasonic driving circuit according to claim 1, wherein the first transmitting and receiving module comprises a first ultrasonic head, a first resistor, a second resistor, a first NMOS transistor and a first capacitor;

3. The ultrasonic driving circuit according to claim 1, further comprising a signal shielding circuit and an electronic switch chip, wherein the signal amplification module is connected to the electronic switch chip through the shielding circuit, and the processor is connected to the signal shielding circuit and the electronic switch chip respectively.

4. The ultrasonic driving circuit according to claim 3, wherein the signal shielding circuit comprises a third resistor, a fourth resistor, a second NMOS transistor, a third NMOS transistor, a second capacitor and a third capacitor;

5. An ultrasonic driving circuit according to claim 3, wherein a secondary signal amplifying module is further provided at the output end of the electronic switch chip.

6. The ultrasonic driving circuit according to claim 1, wherein the boost driving module comprises a fifth resistor, a sixth resistor, a fourth capacitor, a fifth capacitor, an inductor, a fourth NMOS transistor, a diode, and a sixth capacitor;

7. An ultrasonic pulmonary function instrument, which is characterized by comprising an air blowing pipe and an ultrasonic driving circuit, wherein the ultrasonic driving circuit adopts an ultrasonic driving circuit as claimed in any one of claims 1 to 6.

8. The ultrasonic pulmonary function device of claim 7, further comprising a wireless communication module, wherein the wireless communication module is connected to the ultrasonic driving circuit.