Protection circuit capable of rapidly cutting off fan and ventilation equipment

Abstract

The utility model provides a protection circuit capable of rapidly cutting off a fan. The protection circuit comprises a reference voltage circuit, a first operational amplifier, a second operational amplifier and a power management circuit. The first operational amplifier is electrically connected with the pressure sensor and the reference voltage circuit and used for receiving the air pressure voltage and the reference voltage and filtering the air pressure voltage and the reference voltage to obtain enhanced air pressure voltage and enhanced reference voltage. The second operational amplifier is electrically connected with the first operational amplifier and used for receiving the enhanced air pressure voltage and the enhanced reference voltage and comparing the enhanced air pressure voltage with the enhanced reference voltage, and when the enhanced air pressure voltage exceeds the enhanced reference voltage, the second operational amplifier outputs a first control signal; when the enhanced air pressure voltage does not exceed the enhanced reference voltage, a first control signal is output, and the second operational amplifier outputs a second control signal. The power management circuit is electrically connected with the second operational amplifier and used for receiving the first control signal or the second control signal, and when the first control signal is received, the power management circuit controls the fan to cut off a power supply; when the second control signal is received; and the power management circuit supplies power to the fan. In addition, the utility model further provides ventilation equipment.

Description

Technical Field

[0001] The utility model relates to the technical field of ventilation equipment, in particular to a protection circuit for quickly cutting off a fan and ventilation equipment. Background Art

[0002] Ventilation equipment, such as ventilators and oxygen therapy devices, often need to be connected to a fan outlet to receive the air pressure output by the fan to complete ventilation.

[0003] Ventilation equipment generally has a pressure sensor at the fan outlet to detect wind pressure, because excessive wind pressure can easily cause lung damage to the user of the ventilation equipment. Existing ventilation equipment generally issues an alarm when the wind pressure is detected to be too high, so that the user can adjust the wind pressure.

[0004] However, the existing wind pressure adjustment operation also requires a certain reaction time, and the impact of excessive wind pressure on the user's body is still inevitable. Utility Model Content

[0005] In view of this, the utility model provides a protection circuit and ventilation equipment for quickly cutting off the fan.

[0006] In the first aspect, the utility model provides a protection circuit for quickly cutting off a fan, which is applied to ventilation equipment. The ventilation equipment includes a fan and a pressure sensor arranged at the air outlet of the fan, the pressure sensor is used to detect the air pressure output by the fan to obtain an air pressure voltage, and the protection circuit for quickly cutting off the fan includes a reference voltage circuit, a first operational amplifier, a second operational amplifier and a power management circuit. The first operational amplifier is electrically connected to the pressure sensor and the reference voltage circuit, and is used to receive the air pressure voltage and the reference voltage, and filter the air pressure voltage and the reference voltage to obtain an enhanced air pressure voltage and an enhanced reference voltage. The second operational amplifier is electrically connected to the first operational amplifier, and is used to receive the enhanced air pressure voltage and the enhanced reference voltage, and compare the enhanced air pressure voltage and the enhanced reference voltage. When the enhanced air pressure voltage exceeds the enhanced reference voltage, the second operational amplifier outputs a first control signal; when the enhanced air pressure voltage does not exceed the enhanced reference voltage, the first control signal is output, and the second operational amplifier outputs a second control signal. The power management circuit is electrically connected to the second operational amplifier and is used to receive the first control signal or the second control signal. When the first control signal is received, the power management circuit controls the fan to cut off power; when the second control signal is received, the power management circuit supplies power to the fan.

[0007] Furthermore, the first operational amplifier includes a first operational amplifier unit, a second operational amplifier unit, and a third operational amplifier unit. The first operational amplifier unit and the second operational amplifier unit are electrically connected to the pressure sensor and the reference voltage circuit, respectively, and respectively receive the air pressure voltage and the reference voltage provided by the reference voltage circuit, and filter the air pressure voltage and the reference voltage to obtain an enhanced air pressure voltage and an enhanced reference voltage.

[0008] Furthermore, the first operational amplifier also includes a third operational amplifier unit, and the protection circuit for quickly cutting off the fan also includes a power supply circuit, the power supply circuit includes a voltage source, a first electronic switch, and an output end, and the output end of the third operational amplifier unit is electrically connected to the voltage source through the electronic switch. When the output end voltage of the third operational amplifier unit is greater than the voltage provided by the voltage source, the first electronic switch is turned on, and the output end of the power supply circuit outputs a working voltage to the second operational amplifier, so as to start the second operational amplifier.

[0009] Furthermore, the first electronic switch is a triode, the base of the first electronic switch is electrically connected to the positive output terminal of the third operational amplifier unit, the collector is electrically connected to the voltage source, the emitter is electrically connected to the negative input terminal of the third operational amplifier unit through a resistor, and the output terminal of the power supply circuit is located between the emitter and the resistor.

[0010] Furthermore, the first control signal is at a high level, and the second control signal is at a low level.

[0011] Furthermore, the power management circuit includes a second electronic switch and a third electronic switch, the second electronic switch and the third electronic switch are electrically connected, the third electronic switch is electrically connected to the fan power supply, and the second electronic switch is electrically connected to the output end of the second operational amplifier. When the output end of the second operational amplifier outputs the first control signal, the second electronic switch and the third electronic switch are turned off, and the fan power supply is cut off.

[0012] Further, the second electronic switch and the third electronic switch are a triode and a field effect transistor respectively, the drain of the second electronic switch is electrically connected to a voltage source, the source is grounded through a resistor, and the gate is electrically connected to the third electronic switch. The base of the third electronic switch is electrically connected to the output of the second operational amplifier as an input end of the power management circuit. The collector of the third electronic switch is electrically connected to the gate of the second electronic switch. The emitter E of the third electronic switch is grounded.

[0013] Furthermore, the first operational amplifier further includes a fourth operational amplifier unit, the fourth operational amplifier unit is idle, and the second operational amplifier only includes one operational amplifier unit.

[0014] Further, the positive input terminal of the first operational amplifier unit is electrically connected to the sensor for receiving the air pressure voltage, and the negative input terminal of the first operational amplifier unit is electrically connected to the output terminal; the positive input terminal of the second operational amplifier unit is electrically connected to the reference voltage circuit for receiving the reference voltage, and the negative input terminal of the second operational amplifier unit is electrically connected to the output terminal, and the output terminals of the first operational amplifier unit and the second operational amplifier unit are respectively electrically connected to the positive input terminal and the negative input terminal of the second operational amplifier.

[0015] In a second aspect, the utility model provides a ventilation device, comprising: a fan and a pressure sensor, and the ventilation device also includes the above-mentioned protection circuit for quickly cutting off the fan.

[0016] The above-mentioned quick-cut-off fan protection circuit and ventilation equipment can quickly cut off the fan protection circuit and automatically cut off the fan power supply when it is detected that the air pressure output by the fan is excessive, thereby avoiding the influence of excessive air pressure on the user's body caused by the ventilation equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0018] Figure 1 A schematic diagram of a protection circuit for quickly cutting off a fan provided in an embodiment of the utility model.

[0019] Figure 2 A circuit schematic diagram of a protection circuit for quickly cutting off a fan provided in an embodiment of the utility model.

[0020] Figure 3 A schematic diagram of a ventilation device provided in an embodiment of the utility model.

[0021] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.

[0023] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar planning objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate. In other words, the described embodiments are implemented according to a sequence other than that illustrated or described herein. In addition, the terms "including" and "having" and any of their variations may also include other content. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to only those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0024] It should be noted that the descriptions of "first", "second", etc. in this application are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0025] The present application provides a protection circuit for quickly cutting off the fan of a ventilation device. When it is detected that the fan output pressure is too high, the fan is automatically turned off and the fan is cut off from the ventilation device, thereby preventing the ventilation device from causing damage to the user's body due to excessive air pressure.

[0026] Please see Figure 1 and Figure 3 , Figure 1 A protection circuit 1 for quickly cutting off the fan is shown. Figure 3 Schematic diagram of a ventilation device using a protection circuit 1 for quickly cutting off the fan. The protection circuit 1 is applied to a ventilation device 100. The ventilation device 100 also includes a fan 2 and a pressure sensor 3. The pressure sensor 3 is arranged on the fan 2 and is used to detect the air pressure output by the fan 20 to obtain an air pressure voltage. The protection circuit 1 is used to cut off the fan 20 when the air pressure voltage detected by the pressure sensor 3 exceeds the reference voltage, so that the fan 20 stops working, that is, stops outputting air pressure. The pressure sensor 3 is a device that converts air pressure into an electrical signal. For example, a resistive pressure sensor, a ceramic pressure sensor, etc. The fan 20 is a turbine fan.

[0027] The protection circuit 1 includes a first operational amplifier 10, a second operational amplifier 20, a power supply circuit 40, a reference voltage circuit 50, and a power management circuit 60. The first operational amplifier 10 is electrically connected to the pressure sensor 3, the power supply circuit 40, and the reference voltage circuit 50. The second operational amplifier 20 is connected to the first operational amplifier 10 and the power management circuit 60. The pressure sensor 3 is used to detect the air pressure output by the fan 2 and convert it into an air pressure voltage V d0 The reference voltage circuit 50 is used to provide a reference voltage V f0 The power supply circuit 40 is used to provide the second operational amplifier 20 with an operating voltage V y The power management circuit 40 is electrically connected to the fan 2 and is used to power on or off the fan 2 .

[0028] The first operational amplifier 10 is used to receive the air pressure voltage V provided by the pressure sensor 3 d0 and the reference voltage V provided by the reference voltage circuit 50 f0 , and the air pressure voltage V d0 And the reference voltage V f0 After filtering, the enhanced air pressure voltage V is obtained d1 And enhance the reference voltage V f1 The first operational amplifier 10 is also used to provide a voltage V y The voltage is stabilized to keep the power supply circuit 40 always providing a constant voltage V y .

[0029] The second operational amplifier 20 provides a voltage V y The second operational amplifier 20 is used to receive the enhanced gas pressure voltage V output by the first operational amplifier 10. d1 And enhance the reference voltage V f1 , and compare the enhanced gas pressure voltage V d1 And enhance the reference voltage V f1 When the pressure voltage V d1 Exceeds the enhanced reference voltage V f1 , then the first control signal is output. When the pressure voltage V d1 Does not exceed the enhanced reference voltage V f1 , then the second control signal is output.

[0030] The power management circuit 40 controls the fan 2 to be powered off according to the first control signal. The power management circuit 40 controls the fan 2 to be powered on according to the second control signal.

[0031] Please refer to Figure 2 , Figure 2The circuit schematic diagram of the protection circuit 1 is shown. The first operational amplifier 10 is an LM324DG4 amplifier. The first operational amplifier 10 includes four AND operational amplifier units. Specifically, the first operational amplifier 10 includes a first operational amplifier unit 11, a second operational amplifier unit 12, a third operational amplifier unit 13, and a fourth operational amplifier unit 14. Among them, the fourth operational amplifier unit 14 is idle.

[0032] The positive input terminal I1 of the first operational amplifier unit 11 is electrically connected to the pressure sensor 3 and is used to receive the air pressure voltage V provided by the pressure sensor 3. d0 , and the gas pressure voltage V d0 After filtering, the enhanced air pressure voltage V d1 . Enhance the gas pressure voltage V d1 The signal is outputted through the output terminal O1 of the first operational amplifier unit 11 .

[0033] The positive input terminal I2 of the second operational amplifier unit 12 is electrically connected to the reference voltage circuit 50 for receiving the reference voltage V provided by the reference voltage circuit 50. f0 , and the gas pressure voltage V d0 After filtering, the reference voltage V f1 . The reference voltage V f1 The signal is outputted through the output terminal O2 of the second operational amplifier unit 12 .

[0034] The negative input terminal I of the third operational amplifier unit 13 3- Electrically connected to the power supply circuit 40, used to make the power supply circuit 40 output a constant voltage V y The positive input terminal I3 of the third operational amplifier unit 13 is electrically connected to the reference voltage circuit 50 . The output terminal O3 of the third operational amplifier unit 13 is electrically connected to the power supply circuit 40 .

[0035] The power supply circuit 40 includes a first electronic switch Q1 and a voltage source V CC1 The first electronic switch Q1 is electrically connected to the output terminal O3 of the third operational amplifier unit 13, the voltage source V CC1 , and is electrically connected to the negative input terminal I3 of the third operational amplifier unit 13 through the resistor R1. CC1 The voltage is V C When the output voltage V o Greater than the voltage source V CC1 The voltage V C When the first electronic switch Q1 is turned on, the output terminal O4 of the power supply circuit 40 outputs a voltage V y The output terminal O4 of the power supply circuit 40 is located between the first electronic switch Q1 and the resistor R1.

[0036] In this embodiment, the first electronic switch Q1 is a transistor Q １。 Transistor Q １ The base b is electrically connected to the output terminal O3 of the third operational amplifier unit 13, and the collector c is electrically connected to the voltage source V CC1 The emitter electrode e is electrically connected to the negative input terminal I of the third operational amplifier unit 13 through the resistor R1. 3- The output terminal O4 of the power supply circuit 40 is located between the emitter e and the resistor R1. In some feasible embodiments, the first electronic switch Q1 can also be a field effect transistor. Since the voltage V output by the output terminal O3 of the third operational amplifier unit 13 o is constant, therefore, the voltage source V CC1 Output voltage V y It is also constant.

[0037] The second operational amplifier 20 includes a power input terminal V DD , positive input terminal I5, negative input terminal I -5、 And output terminal O5. Power input terminal V DD The positive input terminal I5 and the negative input terminal I -5 are electrically connected to the output terminal O1 and the output terminal O2 of the first operation unit 10, respectively, and are used to receive the enhanced gas pressure voltage V d1 And enhance the reference voltage V f1 , and to enhance the gas pressure voltage V d1 And enhance the reference voltage V f1 For comparison, when the pressure voltage V d1 Exceeding the boost pressure voltage V f1 When the pressure voltage V d1 Does not exceed the enhanced gas pressure voltage V f1 When the first control signal is high, the output terminal O5 of the second operational amplifier 20 outputs the second control signal. In this embodiment, the first control signal is at a high level, and the second control signal is at a low level. In this embodiment, the second operational amplifier 20 includes only one operational amplifier unit.

[0038] The power management circuit 40 is used for the fan power supply V CC2 Supply power to fan 2 or cut off the fan power supply V CC2 Specifically, the power management circuit 40 includes an input terminal I6, a second electronic switch Q2, and a third electronic switch Q3. The input terminal I6 is electrically connected to the output terminal O5 of the second operational amplifier 20. The second electronic switch Q2 is electrically connected to the fan power supply V CC2The second electronic switch Q2 is also electrically connected to the third electronic switch Q3. The third electronic switch Q3 is also electrically connected to the input terminal I6, and is used to receive the first control signal or the second control signal output by the second operational amplifier 20. When the first control signal is received, that is, when a high level is received, the third electronic switch Q3 and the second electronic switch Q2 are not turned on. At this time, the fan power supply VCC2 On the contrary, when the second control signal is received, that is, when a low level is received, the third electronic switch Q3 and the second electronic switch Q2 are turned on. At this time, the fan power supply VCC2 The fan 2 is powered and operates normally. In this embodiment, the second electronic switch Q2 is a field effect transistor. The third electronic switch Q3 is an NPN transistor. The drain D of the second electronic switch Q2 is electrically connected to a voltage source. VCC2 , the source S is grounded through a resistor, and the gate G is electrically connected to the third electronic switch Q3. The base b of the third electronic switch Q3 is electrically connected to the output terminal O5 of the second operational amplifier 20 as the input terminal I6 of the power management circuit 40. The collector C of the third electronic switch Q3 is electrically connected to the gate G of the second electronic switch Q2. The emitter E of the third electronic switch Q3 is grounded. It can be understood that the first control signal and the second control signal can also be represented by other levels. For example, the first control signal is a low level and the second control signal is a high level. It only needs to change the type or connection relationship of the second electronic switch Q2 and the third electronic switch Q3 accordingly.

[0039] The above-mentioned quick-cut-off fan protection circuit and ventilation equipment can quickly cut off the fan protection circuit and automatically cut off the fan power supply when it is detected that the air pressure output by the fan is excessive, thereby avoiding the influence of excessive air pressure on the user's body caused by the ventilation equipment.

[0040] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

[0041] The above examples are only preferred embodiments of the present application, and certainly cannot be used to limit the scope of rights of the present application. Therefore, equivalent changes made according to the claims of the present application still fall within the scope covered by the present application.

Claims

1. A protection circuit for quickly cutting off a fan, applied to ventilation equipment, the ventilation equipment comprising a fan and a pressure sensor arranged at the air outlet of the fan, the pressure sensor being used to detect the air pressure output by the fan to obtain an air pressure voltage, It is characterized in that The protection circuit for quickly cutting off the fan comprises: A reference voltage circuit, used for providing a reference voltage; a first operational amplifier, electrically connected to the pressure sensor and the reference voltage circuit, for receiving the air pressure voltage and the reference voltage, and filtering the air pressure voltage and the reference voltage to obtain an enhanced air pressure voltage and an enhanced reference voltage; a second operational amplifier, electrically connected to the first operational amplifier, for receiving the enhanced air pressure voltage and the enhanced reference voltage, and comparing the enhanced air pressure voltage and the enhanced reference voltage, and when the enhanced air pressure voltage exceeds the enhanced reference voltage, the second operational amplifier outputs a first control signal; when the enhanced air pressure voltage does not exceed the enhanced reference voltage, the first control signal is output, and the second operational amplifier outputs a second control signal; The power management circuit is electrically connected to the second operational amplifier and is used to receive the first control signal or the second control signal. When the first control signal is received, the power management circuit controls the fan to cut off power; when the second control signal is received, the power management circuit supplies power to the fan.

2. The protection circuit for rapidly cutting off the fan as claimed in claim 1, It is characterized in that The first operational amplifier includes a first operational amplifier unit, a second operational amplifier unit, and a third operational amplifier unit. The first operational amplifier unit and the second operational amplifier unit are electrically connected to the pressure sensor and the reference voltage circuit, respectively, receive the air pressure voltage and the reference voltage provided by the reference voltage circuit, and filter the air pressure voltage and the reference voltage to obtain an enhanced air pressure voltage and an enhanced reference voltage.

3. The protection circuit for rapidly cutting off the fan as claimed in claim 2, It is characterized in that The first operational amplifier also includes a third operational amplifier unit, and the protection circuit for quickly cutting off the fan also includes a power supply circuit, the power supply circuit includes a voltage source, a first electronic switch, and an output end. The output end of the third operational amplifier unit is electrically connected to the voltage source through the electronic switch. When the output end voltage of the third operational amplifier unit is greater than the voltage provided by the voltage source, the first electronic switch is turned on, and the output end of the power supply circuit outputs a working voltage to the second operational amplifier, so as to start the second operational amplifier.

4. The protection circuit for rapidly cutting off the fan as claimed in claim 3, It is characterized in that The first electronic switch is a triode, the base of the first electronic switch is electrically connected to the positive output terminal of the third operational amplifier unit, the collector is electrically connected to the voltage source, the emitter is electrically connected to the negative input terminal of the third operational amplifier unit through a resistor, and the output terminal of the power supply circuit is located between the emitter and the resistor.

5. The protection circuit for rapidly cutting off the fan as claimed in claim 3, It is characterized in that The first control signal is at a high level, and the second control signal is at a low level.

6. The protection circuit for rapidly cutting off the fan as claimed in claim 5, It is characterized in that The power management circuit includes a second electronic switch and a third electronic switch, the second electronic switch and the third electronic switch are electrically connected, the third electronic switch is electrically connected to the fan power supply, and the second electronic switch is electrically connected to the output end of the second operational amplifier. When the output end of the second operational amplifier outputs the first control signal, the second electronic switch and the third electronic switch are turned off, and the fan power supply is cut off.

7. The protection circuit for rapidly cutting off the fan as claimed in claim 6, It is characterized in that The second electronic switch and the third electronic switch are respectively a triode and a field effect transistor, the drain of the second electronic switch is electrically connected to a voltage source, the source is grounded through a resistor, and the gate is electrically connected to the third electronic switch; the base of the third electronic switch is electrically connected to the output of the second operational amplifier as an input end of the power management circuit, the collector of the third electronic switch is electrically connected to the gate of the second electronic switch, and the emitter of the third electronic switch is grounded.

8. The protection circuit for rapidly cutting off the fan as claimed in claim 1, It is characterized in that The first operational amplifier further includes a fourth operational amplifier unit, the fourth operational amplifier unit is idle, and the second operational amplifier includes only one operational amplifier unit.

9. The protection circuit for rapidly cutting off the fan as claimed in claim 2, It is characterized in that The positive input terminal of the first operational amplifier unit is electrically connected to the sensor for receiving the air pressure voltage, and the negative input terminal of the first operational amplifier unit is electrically connected to the output terminal; the positive input terminal of the second operational amplifier unit is electrically connected to the reference voltage circuit for receiving the reference voltage, and the negative input terminal of the second operational amplifier unit is electrically connected to the output terminal, and the output terminals of the first operational amplifier unit and the second operational amplifier unit are electrically connected to the positive input terminal and negative input terminal of the second operational amplifier, respectively.

10. A ventilation device, include: The fan and pressure sensor are characterized in that the ventilation equipment also includes a protection circuit for quickly cutting off the fan as described in any one of claims 1 to 9.

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