Control circuit of inflator pump, inflator pump and pulmonary function instrument

Abstract

The embodiment of the utility model belongs to the field of electronic circuits, and relates to a control circuit of an inflator pump, which comprises a controller, a driving circuit and a power supply circuit of the inflator pump, the driving circuit comprises a push-pull circuit, and the input end and the output end of the push-pull circuit are respectively in coupling connection with the controller and the power supply circuit; the controller is used for outputting a pwm control signal; and the driving circuit is used for controlling the conduction state of the power supply circuit according to the pwm control signal. The utility model further relates to an inflator pump and a pulmonary function instrument. According to the technical scheme provided by the invention, the driving capability of the inflator pump control circuit can be improved.

Description

Technical Field

[0001] This application relates to the field of electronic circuit technology, and more specifically, to a control circuit for an air pump, an air pump, and a pulmonary function instrument. Background Technology

[0002] An air pump is a power device that converts mechanical energy into gas pressure energy, and it is widely used in medical, industrial, and automotive fields. In the medical field, air pumps focus on achieving precise, safe, and reliable gas power output. Therefore, air pumps often use pulse width modulation (PWM) signals from a microcontroller unit (MCU) for precise drive control.

[0003] However, using PWM signals places high demands on the driving capability of the air pump's control circuit. If the driving capability of the air pump's control circuit is insufficient, and the switching speed of the PWM signal sent by the MCU control unit is too fast, it may cause the control switch of the air pump's load circuit to overheat or even burn out. On the other hand, if the switching speed of the PWM signal sent by the MCU control unit is slow, below 20kHz, a sharp buzzing sound can be heard by the human ear, and electromagnetic interference problems such as EMI will be generated during the air pump's startup process. Utility Model Content

[0004] The technical problem to be solved by the embodiments of this application is how to improve the driving capability of the air pump control circuit.

[0005] To address the aforementioned technical problems, a first aspect of this application provides a control circuit for an air pump, comprising:

[0006] The power supply circuit for the controller, drive circuit, and air pump;

[0007] The driving circuit includes a push-pull circuit, the input and output terminals of which are coupled to the controller and the power supply circuit, respectively.

[0008] The controller is used to output PWM control signals;

[0009] The driving circuit is used to control the conduction state of the power supply circuit according to the PWM control signal.

[0010] Furthermore, the driving circuit also includes a transistor, the base of which is coupled to the control pin of the controller, and the collector of which is coupled to the input terminal of the push-pull circuit.

[0011] Furthermore, the power supply circuit includes a first field-effect transistor, and the output terminal of the push-pull circuit is connected to the gate of the first field-effect transistor.

[0012] Furthermore, the push-pull circuit includes a second field-effect transistor and a third field-effect transistor. The gates of the second and third field-effect transistors are connected and then connected in parallel with the collector of the transistor. The drains of the second and third field-effect transistors are connected and then connected with the gate of the first field-effect transistor.

[0013] Furthermore, the first and second field-effect transistors are NMOS transistors, and the third field-effect transistor is a PMOS transistor.

[0014] Furthermore, the driving circuit also includes a capacitor, one end of which is connected between the drain of the second field-effect transistor and the gate of the first field-effect transistor, and the other end of which is connected to ground.

[0015] Furthermore, a pull-up resistor is coupled between the control pin of the controller and the base of the transistor.

[0016] Furthermore, the power supply circuit is provided with a voltage sampling point, and the controller is coupled to the voltage sampling point. The controller is used to modulate the PWM control signal according to the voltage value of the voltage sampling point.

[0017] To address the aforementioned technical problems, a second aspect of this application provides an air pump, wherein the air pump includes the control circuit described in the first aspect and any one thereof.

[0018] To address the aforementioned technical problems, a third aspect of this application also provides a pulmonary function instrument, wherein the pulmonary function instrument includes an air pump as described in the second aspect.

[0019] Compared with the prior art, the embodiments of this application have the following main advantages:

[0020] In the control circuit of the air pump of this application, a push-pull circuit is introduced. Based on the principle that the two power transistors of the push-pull circuit work in a cycle within one PWM period, the characteristics of the power supply voltage and the power transistors can be fully utilized to improve the driving capability of the air pump control circuit. Attached Figure Description

[0021] To more clearly illustrate the solution of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 A circuit diagram of a control circuit for an air pump according to an embodiment of this application is shown;

[0023] Figure 2 A circuit design schematic diagram of a specific embodiment of the control circuit for an air pump is shown. Detailed Implementation

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this application are used to distinguish different objects, not to describe a particular order.

[0025] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0026] The following reference Figure 1 , Figure 1 A circuit diagram of a control circuit for an air pump according to an embodiment of this application is shown. As shown in the figure, the control circuit for the air pump includes:

[0027] The system includes a controller, a drive circuit, and a power supply circuit for the air pump. The controller can be an ARM-Cortex M7 series microcontroller, such as the STM32F767VIT6, used to output PWM control signals. Since the initial PWM control signal level of the controller is often insufficient to directly drive the air pump's control circuit, a drive circuit is also included in the power supply circuits of both the controller and the air pump. This drive circuit converts the PWM control signal into the drive signal required by the power supply circuit, providing sufficient current or power to drive the load circuit and thus controlling the conduction state of the air pump's power supply circuit.

[0028] It should be noted that conventional drive circuits have limited driving capability. To further improve the driving capability of the drive circuit, the drive circuit in this embodiment includes a push-pull circuit. The input and output terminals of this push-pull circuit are coupled to the controller and the power supply circuit, respectively. This push-pull circuit may include two symmetrical power transistors, which operate alternately. In one cycle, only one transistor is on, while the other is off, avoiding power supply short-circuit losses caused by both transistors conducting simultaneously. Therefore, it has high efficiency, especially at high power output, where the efficiency advantage is more obvious. In addition, since the two transistors provide current to the load alternately, the characteristics of the power supply voltage and the power transistors can be fully utilized to output greater power.

[0029] Compared with the prior art, the embodiments of this application have the following main advantages:

[0030] In the control circuit of the air pump of this application, a push-pull circuit is introduced. Based on the principle that the two power transistors of the push-pull circuit work in a cycle within one PWM period, the characteristics of the power supply voltage and the power transistors can be fully utilized to improve the driving capability of the air pump control circuit.

[0031] Furthermore, based on Figure 1 The circuit diagram of the air pump control circuit shown is for reference only. Figure 2 , Figure 2 A circuit design schematic diagram of a specific embodiment of the control circuit for an air pump is shown.

[0032] In this specific embodiment, the control circuit of the air pump includes a controller, a power supply circuit for the air pump, and a drive circuit located between the controller and the power supply circuit.

[0033] like Figure 2 As shown in the circuit diagram, Pump_ctrol is the output pin of the controller, representing the controller. VCC_Pump provides the drive power for the air pump motor. The power supply circuit for the air pump includes capacitor C253, capacitor C47, inductor L22, capacitor C254, capacitor C255, diode D11, first field-effect transistor Q6, and resistor R141, etc. Pumb_VCC represents the positive power output of the pump motor, and Pumb_GND represents the ground terminal of the pump motor. The drive circuit includes transistor Q31, second field-effect transistor Q33, third field-effect transistor Q32, resistor R262, resistor R116, resistor R46, and capacitor C262.

[0034] Furthermore, the second field-effect transistor Q33 and the third field-effect transistor Q32 form a push-pull circuit. The base of transistor Q31 is coupled to the control pin Pump_ctrol of the controller, and the collector of transistor Q31 is coupled to the input terminal of the push-pull circuit, i.e., the common gate point of the second field-effect transistor Q33 and the third field-effect transistor Q32. In addition, the output terminal of the push-pull circuit, i.e., the common drain point of the second field-effect transistor Q33 and the third field-effect transistor Q32, is connected to the gate of the first field-effect transistor Q6. Furthermore, both the first field-effect transistor Q6 and the second field-effect transistor Q33 are NMOS transistors, and the third field-effect transistor Q32 is a PMOS transistor.

[0035] Therefore, the circuit principle of this control circuit is explained as follows: The MCU control pin Pump_Ctrol sends a PWM wave signal. When Pump_Ctrol sends a low level, transistor Q31 is turned off, the second MOSFET Q33 is turned on, the third MOSFET Q32 is turned off, and the first MOSFET Q6 is turned on, at which time the power supply circuit of the air pump is on. When Pump_Ctrol sends a high level, transistor Q31 is turned on, the second MOSFET Q33 is turned off, the third MOSFET Q32 is turned on, and the first MOSFET Q6 is turned off, at which time the power supply circuit of the air pump is off. Since the second MOSFET Q33 and the third MOSFET Q32 in the circuit work in a cycle within one PWM waveform, only one transistor is on and the other is off within one cycle. This avoids the power short-circuit loss caused by both transistors being on at the same time, and can make full use of the power supply voltage and the characteristics of the power transistors to output greater power, increasing the driving capability. Thus, it solves the problem of the first MOSFET Q6 overheating when the PWM speed is high.

[0036] Furthermore, the driving circuit also includes capacitor C262. One end of capacitor C262 is connected between the drain of the second field-effect transistor Q33 and the gate of the first field-effect transistor Q6, and the other end of capacitor C262 is grounded. This capacitor C262 serves to filter and stabilize the voltage, preventing voltage fluctuations from affecting subsequent circuits.

[0037] Furthermore, a pull-up resistor R185 is coupled between the controller's control pin Pump_ctrol and the base of transistor Q31. VCC33 is 3.3V, which is the MCU's matching level. The pull-up resistor R185 can limit current to prevent the air pump from turning on momentarily when Pump_ctrol is initialized to a low level.

[0038] Furthermore, a voltage sampling point, Pumb_Check, is set in the power supply circuit. The controller is coupled to the voltage sampling point Pumb_Check and modulates the PWM control signal based on the voltage value of the voltage sampling point Pumb_Check. Specifically, VCC_Pump is 24V and VCC_12 Pump is 12V. Because the Vgs (Vg-Vs) of Q6 cannot exceed 20V, Pump_Current here converts current to voltage. After the voltage is sampled, it flows into the subsequent operational amplifier and then into the ADC unit of the controller. The voltage calculation formula is: V=0.03R*Ia*Au (Au is the operational amplifier multiple, and 0.03R is the sampling resistor). If the current that the MCU needs to protect is set to Ia, the Pumb_Check protection voltage is 0.03R*Ia*Au V. After the MCU receives this value and it is within the set range, it can monitor the magnitude of the air pump current to achieve the protection effect.

[0039] To address the aforementioned technical problems, this application also provides an air pump, which includes as follows: Figure 1 or Figure 2 The control circuit of the air pump is shown.

[0040] To address the aforementioned technical problems, this application also provides a pulmonary function instrument, which includes the aforementioned air pump.

[0041] Specifically, the pulmonary function instrument can be a desktop pulmonary function instrument, and the air pump can be applied to the plethysmography chamber in the desktop pulmonary function instrument to control the chamber pressure.

[0042] Obviously, the embodiments described above are only some embodiments of this application, not all embodiments. The accompanying drawings show preferred embodiments of this application, but do not limit the patent scope of this application. This application can be implemented in many different forms; rather, the purpose of providing these embodiments is to provide a more thorough and comprehensive understanding of the disclosure of this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing specific embodiments, or make equivalent substitutions for some of the technical features. Any equivalent structures made using the content of this application's specification and drawings, directly or indirectly applied to other related technical fields, are similarly within the scope of patent protection of this application.

Claims

1. A control circuit for an air pump, characterized in that, include: The power supply circuit for the controller, drive circuit, and air pump; The driving circuit includes a push-pull circuit, the input and output terminals of which are coupled to the controller and the power supply circuit, respectively. The controller is used to output PWM control signals; The driving circuit is used to control the conduction state of the power supply circuit according to the PWM control signal; the driving circuit also includes a transistor, the base of which is coupled to the control pin of the controller, and the collector of which is coupled to the input terminal of the push-pull circuit.

2. The control circuit according to claim 1, characterized in that, The power supply circuit includes a first field-effect transistor, and the output terminal of the push-pull circuit is connected to the gate of the first field-effect transistor.

3. The control circuit according to claim 2, characterized in that, The push-pull circuit includes a second field-effect transistor and a third field-effect transistor. The gates of the second and third field-effect transistors are connected and then connected in parallel with the collector of the transistor. The drains of the second and third field-effect transistors are connected and then connected to the gate of the first field-effect transistor.

4. The control circuit according to claim 3, characterized in that, The first and second field-effect transistors are NMOS transistors, and the third field-effect transistor is a PMOS transistor.

5. The control circuit according to claim 4, characterized in that, The driving circuit also includes a capacitor, one end of which is connected between the drain of the second field-effect transistor and the gate of the first field-effect transistor, and the other end of which is connected to ground.

6. The control circuit according to any one of claims 1-4, characterized in that, A pull-up resistor is also coupled between the control pin of the controller and the base of the transistor.

7. The control circuit according to any one of claims 1-4, characterized in that, The power supply circuit is provided with a voltage sampling point, and the controller is coupled to the voltage sampling point. The controller is used to modulate the PWM control signal according to the voltage value of the voltage sampling point.

8. An air pump, characterized in that, The air pump includes the control circuit as described in any one of claims 1-7.

9. A pulmonary function instrument, characterized in that, The pulmonary function instrument includes the air pump as described in claim 8.

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