Fan control circuit and air conditioner

Abstract

The application discloses a fan control circuit and an air conditioner. The fan control circuit is connected with a fan. The fan control circuit comprises a control module, a sampling module and a detection module. The control module outputs a fan current to control the start of the fan when the fan starts. The sampling module samples and amplifies the fan current to output an amplified signal. The detection module is used for outputting a first detection signal when the voltage of the amplified signal is less than or equal to a first threshold value, outputting a second detection signal when the voltage of the amplified signal is greater than the first threshold value and less than a second threshold value, and outputting a third detection signal when the voltage of the amplified signal is greater than or equal to the second threshold value. The control module further adjusts the fan current according to the first detection signal, the second detection signal or the third detection signal, can meet the start of the fan in different working modes, improves the test accuracy of the fan, and reduces the damage rate of the fan.

Description

Technical Field

[0001] This application relates to the field of electronic technology, specifically to a fan control circuit and an air conditioner. Background Technology

[0002] Currently, heating unit fans are mainly used for energy exchange between the system and the outside environment, adjusting water temperature to achieve heating or cooling. In practical applications, when the fan is started as a complete unit, the required starting torque is large due to the connection of the relatively large fan blades; however, during motherboard tooling testing, the fan is either unloaded or with small fan blades, resulting in insufficient actual starting torque, which affects the accuracy of hardware function testing. Utility Model Content

[0003] This application provides a fan control circuit and an air conditioner that can meet the startup requirements of the fan in different working modes, improve the testing accuracy of the fan, and reduce the damage rate of the fan.

[0004] In a first aspect, embodiments of this application provide a fan control circuit, the fan control circuit being connected to a fan, the fan control circuit comprising: a control module connected to the fan; the control module being configured to output a fan current to control the fan startup when the fan starts; a sampling module connected to the control module, the sampling module being configured to sample and amplify the fan current to output an amplified signal; and a detection module connected to both the sampling module and the control module; the detection module being configured to output a first detection signal when the voltage of the amplified signal is less than or equal to a first threshold, output a second detection signal when the voltage of the amplified signal is greater than the first threshold and less than a second threshold, and output a third detection signal when the voltage of the amplified signal is greater than or equal to the second threshold; the control module is further configured to adjust the fan current according to the first detection signal, the second detection signal, or the third detection signal.

[0005] In some embodiments, the detection module includes a first switching unit, a second switching unit, and a third switching unit; when the voltage of the amplified signal is less than or equal to a first threshold, the first switching unit is turned on, and the second switching unit and the third switching unit are turned off; when the voltage of the amplified signal is greater than the first threshold and less than the second threshold, the first switching unit and the second switching unit are turned on, and the third switching unit is turned off; when the voltage of the amplified signal is greater than or equal to the second threshold, the first switching unit, the second switching unit, and the third switching unit are all turned on.

[0006] In some embodiments, the first switching unit includes resistors R9, R6, and R12, and transistor T1; the first end of resistor R9 is connected to the sampling module, the second end of resistor R9 is connected to the base of transistor T1, the collector of transistor T1 is connected to the power supply through resistor R6, the emitter of transistor T1 is connected to the first end of resistor R12 and the control module, and the second end of resistor R12 is grounded.

[0007] In some embodiments, the second switching unit includes resistors R10, R7, and R13, and transistor T2; the first end of resistor R10 is connected to the first switching unit, the second end of resistor R10 is connected to the base of transistor T2, the collector of transistor T2 is connected to the power supply through resistor R7, the emitter of transistor T2 is connected to the first end of resistor R13 and the control module respectively, and the second end of resistor R13 is grounded.

[0008] In some embodiments, the third switching unit includes resistors R11, R8, and R14, and transistor T3; the first end of resistor R11 is connected to the second switching unit, the second end of resistor R11 is connected to the base of transistor T3, the collector of transistor T3 is connected to the power supply through resistor R8, the emitter of transistor T3 is connected to the first end of resistor R14 and the control module respectively, and the second end of resistor R14 is grounded.

[0009] In some embodiments, the sampling module includes a sampling unit and an amplification unit connected together. The sampling unit is also connected to the control module, and the amplification unit is also connected to the detection module. The sampling unit is used to sample the fan current and convert the fan current into a sampling voltage. The amplification unit is used to amplify the sampling voltage to output the amplified signal.

[0010] In some embodiments, the sampling unit includes resistors RS1, RS2, RS3, R1, R2, R3, and capacitor C1; the first end of resistor RS1 is connected to the first end of resistor R2 and the control module; the first end of resistor RS2 is connected to the control module; the second end of resistor RS1 is connected to the second end of resistor RS2, the second end of resistor R1, and the first end of resistor RS3; the second end of resistor R1 is connected to the first end of capacitor C1 and the amplification unit; the second end of resistor R2 is connected to the second end of capacitor C1, the first end of resistor R3, and the amplification unit; the second end of resistor RS3 is grounded; and the second end of resistor R3 is connected to the power supply.

[0011] In some embodiments, the amplification unit includes a comparator U1, a resistor R4, a resistor R5, and a capacitor C2; the inverting input of the comparator U1 is connected to the second terminal of the resistor R1 and the first terminal of the resistor R4, the non-inverting input of the comparator U1 is connected to the second terminal of the resistor R2, the output of the comparator U1 is connected to the second terminal of the resistor R4 and the first terminal of the resistor R5, the second terminal of the resistor R5 is connected to the first terminal of the capacitor C2 and the detection module, and the second terminal of the capacitor C2 is grounded.

[0012] In some embodiments, the control module includes: a main control unit and a current control unit, the main control unit being connected to the current control unit and the current control unit being connected to the fan; the main control unit is used to output a main control signal when the fan starts; the current control unit is used to output a fan current according to the main control signal to control the fan to start.

[0013] Secondly, embodiments of this application also provide an air conditioner, which includes a fan and a fan control circuit as described above.

[0014] This application provides a fan control circuit and an air conditioner. The fan control circuit includes a control module, a sampling module, and a detection module. Specifically, when the fan needs to be started, the control module directly outputs an initial fan current to drive the fan to start operating. Next, the sampling module samples and amplifies the fan current to obtain an amplified signal. Then, the detection module divides the amplified signal into three levels and generates corresponding detection signals (first, second, and third detection signals). The control module adjusts the fan current based on the detection signals to achieve graded control, which can meet the starting requirements of the fan in different operating modes, improve the testing accuracy of the fan, and reduce the fan damage rate. Attached Figure Description

[0015] The technical solution and other beneficial effects of this application will become apparent from the following detailed description of specific embodiments in conjunction with the accompanying drawings.

[0016] Figure 1 This is a structural block diagram of the fan control circuit provided in an embodiment of this application.

[0017] Figure 2 This is a structural block diagram of the control module in the wind turbine control circuit provided in an embodiment of this application.

[0018] Figure 3 This is a structural block diagram of the sampling module in the wind turbine control circuit provided in an embodiment of this application.

[0019] Figure 4 This is a structural block diagram of the detection module in the fan control circuit provided in an embodiment of this application.

[0020] Figure 5 This is a schematic diagram of the circuit structure of the fan control circuit and the fan winding of the fan provided in the embodiments of this application. Detailed Implementation

[0021] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Features thus defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0023] Please see Figure 1 This application provides a fan control circuit 100, which is connected to a fan 200. The fan control circuit 100 includes a control module 10, a sampling module 20, and a detection module 30.

[0024] Among them, the control module 10 is connected to the fan 200, the sampling module 20 is connected to the control module 10, and the detection module 30 is connected to the sampling module 20 and the control module 10 respectively.

[0025] Specifically, the control module 10 is used to output the fan current to control the fan 200 to start when the fan 200 starts; the sampling module 20 is used to sample and amplify the fan current to output an amplified signal; the detection module 30 is used to output a first detection signal when the voltage of the amplified signal is less than or equal to a first threshold, output a second detection signal when the voltage of the amplified signal is greater than the first threshold and less than a second threshold, and output a third detection signal when the voltage of the amplified signal is greater than or equal to the second threshold; the control module 10 is also used to adjust the fan current according to the first detection signal, the second detection signal, or the third detection signal.

[0026] In this embodiment, the first threshold and the second threshold are voltage values ​​used in the detection module 30 to divide the amplified signal voltage range, and the first threshold is less than the second threshold. The first threshold and the second threshold are critical values ​​set based on the current demand of the wind turbine operation.

[0027] In practical applications, when the voltage of the amplified signal is less than or equal to the first threshold, the corresponding fan current is at the first level, indicating that the current fan current and starting torque are too low, and the fan is in test mode. At this time, the fan only needs to start with a small torque, but the current starting parameters of the fan are too high, so the starting parameters need to be reduced. When the first threshold is less than the voltage of the amplified signal and less than the second threshold, the corresponding fan current is at the second level, indicating that the current fan current and starting torque are appropriate, and the fan is in working mode. At this time, the fan can start according to the current starting parameters. When the voltage of the amplified signal is greater than or equal to the second threshold, the corresponding fan current is at the third level, indicating that the current fan current and starting torque are too high, and the fan is in abnormal mode, requiring the triggering of fault protection (e.g., controlling the immediate stop of the fan's operation). In this embodiment, through this voltage threshold-based conduction logic difference, the detection module 30 divides the amplified signal into three levels and generates corresponding detection signals, providing a basis for the control module 10 to adjust the fan current. This enables the control module 10 to accurately regulate the fan according to different current ranges, realizing a graded control function to dynamically adapt to the operating requirements of the fan 200.

[0028] Please see Figure 2 In some embodiments, the control module 10 includes a main control unit 11 and a current control unit 12. The main control unit 11 is connected to the current control unit 12, and the current control unit 12 is connected to the fan 200. Specifically, the main control unit 11 outputs a main control signal when the fan 200 starts; the current control unit 12 outputs fan current according to the main control signal to control the fan 200 to start.

[0029] Specifically, the main control unit 11 can be an MCU (Micro Control Unit). Of course, in other embodiments, a control device with the same function can also be selected, and this application does not limit this. The main control unit 11 is used to output main control signals such as SPWM (Sinusoidal Pulse Width Modulation) to the switching transistor of the current control unit 12 according to preset parameters when the fan 200 starts, thereby driving the fan 200 to start. After that, the main control unit 11 adjusts the start-up parameters based on the detection signal fed back by the detection module 30, and adjusts the duty cycle of its output main control signal to realize graded control of the fan current and ensure stable operation.

[0030] Please see Figure 3 In some embodiments, the sampling module 20 includes a sampling unit 21 and an amplification unit 22 connected together. The sampling unit 21 is also connected to the control module 10, and the amplification unit 22 is also connected to the detection module 30.

[0031] Specifically, sampling unit 21 is used to sample the fan current and convert the fan current into a sampling voltage. Amplification unit 22 is used to amplify the sampling voltage to output an amplified signal.

[0032] In practical applications, the sampling unit 21 first collects the fan current from the control module 10 and converts it into a sampling voltage; the amplification unit 22 amplifies the sampling voltage, generates an amplified signal, and finally outputs the amplified signal to the detection module 30.

[0033] Please see Figure 4 In some embodiments, the detection module 30 includes a first switching unit 31, a second switching unit 32, and a third switching unit 33.

[0034] Specifically, when the voltage of the amplified signal is less than or equal to the first threshold, the first switching unit 31 is turned on, and the second switching unit 32 and the third switching unit 33 are turned off. When the voltage of the amplified signal is greater than the first threshold and less than the second threshold, the first switching unit 31 and the second switching unit 32 are turned on, and the third switching unit 33 is turned off. When the voltage of the amplified signal is greater than or equal to the second threshold, the first switching unit 31, the second switching unit 32, and the third switching unit 33 are all turned on.

[0035] In this embodiment, when the voltage of the amplified signal is less than or equal to a first threshold, the first switching unit 31 is configured to be turned on, while the second switching unit 32 and the third switching unit 33 are both configured to be turned off. At this time, the detection module 30 outputs a first detection signal to the control module 10. When the voltage of the amplified signal is greater than the first threshold and less than the second threshold, the first switching unit 31 and the second switching unit 32 are both configured to be turned on, and the third switching unit 33 is configured to be turned off. At this time, the detection module 30 outputs a second detection signal to the control module 10. When the voltage of the amplified signal is greater than or equal to the second threshold, the first switching unit 31, the second switching unit 32, and the third switching unit 33 are all configured to be turned on. At this time, the detection module 30 outputs a third detection signal to the control module 10.

[0036] Please see Figure 5 , Figure 5 This is a schematic diagram of the circuit structure of the fan control circuit 100 and the fan winding 201 of the fan 200 provided in the embodiments of this application.

[0037] like Figure 5As shown, in some embodiments, the fan 200 includes a fan winding 201, which includes a U-phase winding, a V-phase winding, and a W-phase winding. The current control unit 12 includes a U-phase upper arm switch Q1, a V-phase upper arm switch Q2, a W-phase upper arm switch Q3, a U-phase lower arm switch Q4, a V-phase lower arm switch Q5, a W-phase lower arm switch Q6, diodes D1, D2, D3, D4, D5, and D6.

[0038] The control terminals of the upper U-phase switch Q1 and the lower U-phase switch Q4 are respectively connected to the main control unit 11. The input terminal of the upper U-phase switch Q1 is connected to the negative terminal of diode D1 and connected to the power supply. The output terminal of the upper U-phase switch Q1 is connected to the positive terminal of diode D1, the input terminal of the lower U-phase switch Q4, and the U-phase winding. The input terminal of the lower U-phase switch Q4 is also connected to the negative terminal of diode D4. The output terminal of the lower U-phase switch Q4 is connected to the positive terminal of diode D4 and the sampling module 20. The control terminals of the upper V-phase switch Q2 and the lower V-phase switch Q5 are respectively connected to the main control unit 11. The input terminal of the upper V-phase switch Q2 is connected to the negative terminal of diode D1 and connected to the power supply. The output terminal of the upper V-phase switch Q2 is connected to the positive terminal of diode D2, the input terminal of the lower V-phase switch Q5, and the V-phase winding. The input terminal of the lower V-phase switch Q5 is also connected to the negative terminal of diode D5. The output terminal of the lower V-phase switch Q5 is connected to the positive terminal of diode D5 and the sampling module 20. The control terminals of the upper arm switch Q3 and the lower arm switch Q6 of phase W are respectively connected to the main control unit 11. The input terminal of the upper arm switch Q3 of phase W is connected to the negative terminal of diode D3 and connected to the power supply. The output terminal of the upper arm switch Q3 of phase W is connected to the positive terminal of diode D3, the input terminal of the lower arm switch Q6 of phase W, and the phase W winding. The input terminal of the lower arm switch Q6 of phase W is also connected to the negative terminal of diode D6. The output terminal of the lower arm switch Q6 of phase W is connected to the positive terminal of diode D6 and the sampling module 20.

[0039] In this embodiment, a three-phase bridge circuit is formed by the upper and lower arm switching transistors (Q1 to Q6) of the U, V, and W phases and freewheeling diodes (D1 to D6). The control terminals of the switching transistors Q1 to Q6 are connected to the main control unit 11 and are controlled to turn on or off by its main control signal. By controlling the conduction combination of different phase switching transistors, the corresponding fan current is output to the U, V, and W phase windings of the fan winding 201 of the fan 200, driving the fan winding 201 to work. The freewheeling diodes (D1 to D6) are used to provide a freewheeling path when the corresponding switching transistors are turned off, thus protecting the circuit.

[0040] like Figure 5 As shown, in some embodiments, the sampling unit 21 includes resistors RS1, RS2, RS3, R1, R2, R3, and capacitor C1.

[0041] The first end of resistor RS1 is connected to the first end of resistor R2 and the current control unit 12. The first end of resistor RS2 is connected to the current control unit 12. The second end of resistor RS1 is connected to the second end of resistor RS2, the second end of resistor R1 and the first end of resistor RS3. The second end of resistor R1 is connected to the first end of capacitor C1 and the amplification unit 22. The second end of resistor R2 is connected to the second end of capacitor C1, the first end of resistor R3 and the amplification unit 22. The second end of resistor RS3 is grounded and connected to the power supply.

[0042] In this embodiment, the sampling unit 21 samples the current output by the U-phase lower arm switch (i.e., the fan current) through resistor RS1, and converts the fan current into a sampling voltage (following Ohm's law U=IR). At the same time, current limiting protection is achieved through resistors R1 and R2, capacitor C1 is used for filtering, and resistor R3 is connected to the power supply to raise the voltage to a range suitable for subsequent component processing to achieve bias.

[0043] like Figure 5 As shown, in some embodiments, the amplification unit 22 includes a comparator U1, a resistor R4, a resistor R5, and a capacitor C2.

[0044] The inverting input of comparator U1 is connected to the second end of resistor R1 and the first end of resistor R4. The non-inverting input of comparator U1 is connected to the second end of resistor R2. The output of comparator U1 is connected to the second end of resistor R4 and the first end of resistor R5. The second end of resistor R5 is connected to the first end of capacitor C2 and the detection module 30. The second end of capacitor C2 is grounded.

[0045] In this embodiment, in the amplification unit 22, the comparator U1 constitutes an operational amplifier circuit. Its inverting input and non-inverting input respectively receive the sampled voltage, and a negative feedback is formed through resistor R4 to linearly amplify the sampled voltage and output an amplified signal. Furthermore, resistor R5 and capacitor C2 form an RC filter circuit to further filter out the noise introduced during the amplification process and output a smooth and stable amplified signal to the detection module.

[0046] like Figure 5 As shown, in some embodiments, the first switching unit 31 includes resistors R9, R6, and R12, and transistor T1. The first end of resistor R9 is connected to the sampling module 20, the second end of resistor R9 is connected to the base of transistor T1, the collector of transistor T1 is connected to the power supply through resistor R6, the emitter of transistor T1 is connected to the first end of resistor R12 and the control module 10, and the second end of resistor R12 is grounded.

[0047] In some embodiments, the second switching unit 32 includes resistors R10, R7, and R13, and transistor T2. The first end of resistor R10 is connected to the first switching unit 31, the second end of resistor R10 is connected to the base of transistor T2, the collector of transistor T2 is connected to the power supply through resistor R7, the emitter of transistor T2 is connected to the first end of resistor R13 and the control module 10, and the second end of resistor R13 is grounded.

[0048] In some embodiments, the third switching unit 33 includes resistors R11, R8, and R14, and transistor T3. The first end of resistor R11 is connected to the second switching unit 32, the second end of resistor R11 is connected to the base of transistor T3, the collector of transistor T3 is connected to the power supply through resistor R8, the emitter of transistor T3 is connected to the first end of resistor R14 and the control module 10, and the second end of resistor R14 is grounded.

[0049] Specifically, such as Figure 5 As shown, when the voltage of the amplified signal is less than or equal to the first threshold, the voltage between the base and emitter of transistor T1 is greater than the turn-on voltage of transistor T1 (e.g., 0.7V), while the voltage between the base and emitter of transistor T2 is less than the turn-on voltage of transistor T2, and the voltage between the base and emitter of transistor T3 is less than the turn-on voltage of transistor T3. Therefore, at this time, transistor T1 is turned on, and transistors T2 and T3 are turned off. Consequently, the current flows sequentially through resistor R9, the base of transistor T1, the emitter of transistor T1, resistor R12, and finally to ground.

[0050] When the voltage of the amplified signal is greater than the first threshold and less than the second threshold, the voltage between the base and emitter of transistor T1 is greater than the turn-on voltage of transistor T1, the voltage between the base and emitter of transistor T2 is greater than the turn-on voltage of transistor T2, and the voltage between the base and emitter of transistor T3 is less than the turn-on voltage of transistor T3. Therefore, transistors T1 and T2 are turned on at this time, while transistor T3 is turned off. Consequently, current flows sequentially through resistor R9, the base of transistor T1, the emitter of transistor T1, and resistor R12, finally reaching ground; and the current also flows sequentially through resistor R9, resistor R10, the base of transistor T2, the emitter of transistor T2, and resistor R13, finally reaching ground.

[0051] When the voltage of the amplified signal is greater than or equal to the second threshold, the voltage between the base and emitter of transistor T1 is greater than the turn-on voltage of transistor T1, the voltage between the base and emitter of transistor T2 is greater than the turn-on voltage of transistor T2, and the voltage between the base and emitter of transistor T3 is greater than the turn-on voltage of transistor T3. Therefore, transistors T1, T2, and T3 are all turned on at this time. Consequently, the current flows sequentially through resistor R9, the base of transistor T1, the emitter of transistor T1, and resistor R12, finally to ground; and the current also flows sequentially through resistor R9, resistor R10, the base of transistor T2, the emitter of transistor T2, and resistor R13, finally to ground; and the current also flows sequentially through resistor R9, resistor R10, resistor R11, the base of transistor T3, the emitter of transistor T3, and resistor R14, finally to ground.

[0052] In the embodiments of this application, such as Figure 5 As shown, the connection between the detection module 30 and the control module 10 is... Figure 5 At point AD-U in the circuit. When the voltage of the amplified signal is less than or equal to the first threshold, transistor T1 turns on and outputs a current signal, while transistors T2 and T3 are both turned off. At this time, the signal output by the detection unit 32 to the control module 10 is the first detection signal, which indicates that the fan is in test mode. At this time, the fan only needs to start with a small torque, but the current starting parameters of the fan are relatively large, so the control module 10 needs to reduce the starting parameters (e.g., the duty cycle of the SPWM signal). When the first threshold is less than the voltage of the amplified signal and less than the second threshold, transistor T1 turns on and outputs a current signal, transistor T2 also turns on and outputs a current signal, and transistor T3 is turned off. At this time, the signal output by the detection module 30 to the control module 10 is the second detection signal, which indicates that the fan is in working mode. At this time, the control module 10 controls the fan to start according to the current starting parameters (e.g., the duty cycle of the SPWM signal). When the voltage of the amplified signal is greater than or equal to the second threshold, transistors T1, T2, and T3 all conduct and output current signals. At this time, the signal output from the detection module 30 to the control module 10 is the third detection signal. The third detection signal indicates that the fan is in an abnormal mode, and the control module 10 needs to trigger fault protection (e.g., immediately stopping the fan). The current of the first detection signal is less than the current of the second detection signal, which is less than the current of the third detection signal. Therefore, the control module 10 can determine the current detection signal as the specific detection signal among the first, second, and third detection signals based on the current values ​​of each detection signal. This embodiment of the application, through this voltage threshold-based conduction logic difference, divides the amplified signal into three levels and generates corresponding detection signals, providing a basis for the control module to adjust the fan current. This allows the control module to precisely control the fan according to different current ranges, achieving a graded control function.

[0053] Meanwhile, in the control module 10, the main control unit 11 adjusts the start-up parameters based on the detection signal fed back by the detection module 30, that is, it adjusts the duty cycle of the main control signal (SPWM signal) output by the main control unit 11 to the current control unit 12. Thus, the fan current output by the current control unit 12 is adjusted accordingly, so that the fan 200 completes the start-up operation based on the fan current.

[0054] This application provides a fan control circuit 100, which includes a control module 10, a sampling module 20, and a detection module 30. When the fan needs to be started, the control module 10 directly outputs the initial fan current to drive the fan to start operating. Then, the sampling module 20 samples and amplifies the fan current to obtain an amplified signal. Next, the detection module 30 divides the amplified signal into three levels and generates corresponding detection signals (first, second, and third detection signals). The control module 10 adjusts the fan current based on the detection signals to achieve graded control, which can meet the starting requirements of the fan in different operating modes, improve the testing accuracy of the fan, and reduce the damage rate of the fan.

[0055] This application embodiment also provides an air conditioner, which includes a fan 200 and a fan control circuit 100 as described above.

[0056] The fan 200 may include a stator, rotor, controller, and sensors (not shown in the figure). The stator includes a fan winding 201, which is a three-phase winding (U, V, and W phases).

[0057] Specifically, the specific structure and working principle of the fan control circuit 100 can be referred to the above embodiments, and will not be repeated here.

[0058] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0059] The fan control circuit and air conditioner provided in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the technical solutions and core ideas of this application. Those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A fan control circuit, characterized in that, The fan control circuit is connected to the fan, and the fan control circuit includes: A control module is connected to the fan; the control module is used to output fan current to control the fan to start when the fan starts. A sampling module, connected to the control module, is used to sample and amplify the fan current to output an amplified signal; The detection module is connected to the sampling module and the control module respectively. The detection module is used to output a first detection signal when the voltage of the amplified signal is less than or equal to a first threshold, output a second detection signal when the voltage of the amplified signal is greater than the first threshold and less than a second threshold, and output a third detection signal when the voltage of the amplified signal is greater than or equal to the second threshold. The control module is also used to adjust the fan current according to the first detection signal, the second detection signal, or the third detection signal.

2. The blower control circuit of claim 1, wherein, The detection module includes a first switching unit, a second switching unit, and a third switching unit; When the voltage of the amplified signal is less than or equal to the first threshold, the first switching unit is turned on, and the second switching unit and the third switching unit are turned off; When the voltage of the amplified signal is greater than the first threshold and less than the second threshold, the first switching unit and the second switching unit are turned on, and the third switching unit is turned off; When the voltage of the amplified signal is greater than or equal to the second threshold, the first switching unit, the second switching unit, and the third switching unit are all turned on.

3. The fan control circuit according to claim 2, characterized in that, The first switching unit includes resistors R9, R6, and R12, as well as transistor T1; The first end of the resistor R9 is connected to the sampling module, the second end of the resistor R9 is connected to the base of the transistor T1, the collector of the transistor T1 is connected to the power supply through the resistor R6, the emitter of the transistor T1 is connected to the first end of the resistor R12 and the control module respectively, and the second end of the resistor R12 is grounded.

4. The blower control circuit of claim 2, wherein, The second switching unit includes resistors R10, R7, and R13, as well as transistor T2; The first end of the resistor R10 is connected to the first switching unit, the second end of the resistor R10 is connected to the base of the transistor T2, the collector of the transistor T2 is connected to the power supply through the resistor R7, the emitter of the transistor T2 is connected to the first end of the resistor R13 and the control module respectively, and the second end of the resistor R13 is grounded.

5. The fan control circuit of claim 2, wherein, The third switching unit includes resistors R11, R8, and R14, as well as transistor T3; The first end of the resistor R11 is connected to the second switching unit, the second end of the resistor R11 is connected to the base of the transistor T3, the collector of the transistor T3 is connected to the power supply through the resistor R8, the emitter of the transistor T3 is connected to the first end of the resistor R14 and the control module respectively, and the second end of the resistor R14 is grounded.

6. The blower control circuit of claim 1, wherein, The sampling module includes a sampling unit and an amplification unit connected together. The sampling unit is also connected to the control module, and the amplification unit is also connected to the detection module. The sampling unit is used to sample the fan current and convert the fan current into a sampling voltage; The amplification unit is used to amplify the sampled voltage to output the amplified signal.

7. The fan control circuit according to claim 6, characterized in that, The sampling unit includes resistors RS1, RS2, RS3, R1, R2, R3, and capacitor C1; The first end of resistor RS1 is connected to the first end of resistor R2 and the control module. The first end of resistor RS2 is connected to the control module. The second end of resistor RS1 is connected to the second end of resistor RS2, the second end of resistor R1, and the first end of resistor RS3. The second end of resistor R1 is connected to the first end of capacitor C1 and the amplification unit. The second end of resistor R2 is connected to the second end of capacitor C1, the first end of resistor R3, and the amplification unit. The second end of resistor RS3 is grounded and connected to the power supply.

8. The fan control circuit of claim 7, wherein, The amplification unit includes a comparator U1, a resistor R4, a resistor R5, and a capacitor C2; The inverting input of comparator U1 is connected to the second terminal of resistor R1 and the first terminal of resistor R4. The non-inverting input of comparator U1 is connected to the second terminal of resistor R2. The output of comparator U1 is connected to the second terminal of resistor R4 and the first terminal of resistor R5. The second terminal of resistor R5 is connected to the first terminal of capacitor C2 and the detection module. The second terminal of capacitor C2 is grounded.

9. The fan control circuit of claim 1, wherein, The control module includes: The system includes a main control unit and a current control unit, which are connected to each other, and the current control unit is connected to the fan. The main control unit is used to output a main control signal when the fan starts. The current control unit is used to output the fan current according to the main control signal to control the fan to start.

10. An air conditioner characterized by comprising: The air conditioner includes a fan and a fan control circuit as described in any one of claims 1-9.

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