Motor rotating speed control circuit, control method, motor, fan and heat exchange equipment

Abstract

The invention discloses a motor rotating speed control circuit, a control method, a motor, a fan and heat exchange equipment. The control circuit comprises a switch module, the input end of the switch module is connected with a voltage source, the output end of the switch module is connected with a motor interface, the control end of the switch module receives a first control signal, and the switch module is switched on or switched off under the control of a second control signal; the input end of the step-down chip is connected with a voltage source, the output end of the step-down chip is connected with the motor interface, the control end of the step-down chip receives a second control signal, and the step-down chip is put into work or stops working under the control of the first control signal; and the main controller is used for outputting the first control signal and the second control signal. According to the invention, the input voltage of the motor can be changed through a hardware circuit, speed regulation can be realized without changing the duty ratio of PWM waves, a speed regulation chip is not needed, the cost is reduced, the signal interference can be reduced, and the probability of control errors is reduced.

Description

Technical Field

[0001] The present invention relates to the field of electronic power technology, and in particular to a motor speed control circuit, a control method, a motor, a fan and a heat exchange device. Background Art

[0002] Based on the diverse needs of users and different operating conditions, the speed of the motor needs to be adjusted during operation. The existing motor speed regulation solution is to adjust the speed by adjusting the duty cycle of PWM, which requires the configuration of a speed regulation chip, increasing the cost, and the PWM signal is easily interfered, resulting in control errors.

[0003] In view of the problem that in the prior art, the motor needs to adjust the speed by adjusting the duty cycle of PWM through a speed regulating chip, which is costly and has poor anti-interference ability, no effective solution has been proposed yet. Summary of the invention

[0004] The embodiments of the present invention provide a motor speed control circuit, a control method, a motor, a fan and a heat exchange device to solve the problem in the prior art that the motor needs to adjust the speed by adjusting the duty cycle of PWM through a speed regulating chip, which is costly and has poor anti-interference ability.

[0005] In order to solve the above technical problems, the present invention provides a motor speed control circuit, which includes:

[0006] A switch module, whose input end is connected to a voltage source, whose output end is connected to a motor interface, whose control end receives a first control signal, and the switch module is turned on or off under the control of the second control signal;

[0007] A step-down chip, whose input end is connected to a voltage source, whose output end is connected to the motor interface, and whose control end receives a second control signal, and the step-down chip starts working or stops working under the control of the first control signal;

[0008] A main controller is used to output the first control signal and the second control signal.

[0009] Furthermore, the switch module comprises:

[0010] A first controllable switch, a first end of which is connected to the voltage source via a first resistor and a second resistor connected in series, a second end of which is connected to a reference ground, and a control end of which is connected to the main controller via a third resistor, for receiving the first control signal;

[0011] A second controllable switch has a first end connected to the voltage source, a second end connected to the motor interface, and a control end connected between the first resistor and the second resistor.

[0012] Furthermore, the switch module further includes:

[0013] A diode, a cathode of which is connected to the second end of the second controllable switch, and an anode of which is connected to the reference ground.

[0014] Furthermore, the voltage reduction chip includes:

[0015] A first pin, connected to the voltage source;

[0016] a second pin, the second pin being connected to the main controller via a fourth resistor and being used to receive the second control signal, the fourth resistor being further connected to a reference ground via a fifth resistor;

[0017] The third pin is connected to the motor interface through an energy storage inductor.

[0018] Furthermore, the voltage reduction chip further includes:

[0019] A fourth pin, the fourth pin being connected to the third pin via a first capacitor;

[0020] The fifth pin is connected to the motor interface through a sixth resistor, and the sixth resistor is also connected to a reference ground through a seventh resistor.

[0021] Furthermore, the voltage reduction chip further includes:

[0022] A second capacitor and a third capacitor, wherein the second capacitor and the third capacitor are arranged in parallel between the motor interface and a reference ground.

[0023] The present invention also provides a motor, comprising the motor speed control circuit.

[0024] The present invention also provides a fan, comprising the above motor.

[0025] The present invention also provides a heat exchange device, comprising the above-mentioned fan.

[0026] Furthermore, the heat exchange equipment includes at least one of the following: an air conditioner, a refrigerator.

[0027] The present invention also provides a control method, which is applied to the above motor speed control circuit, and the control method comprises:

[0028] Receive motor speed control instructions;

[0029] A first control signal and a second control signal are generated in response to the motor speed control instruction to control the on-off state of the switch module and the working state of the buck chip.

[0030] Further, in response to the motor speed control instruction, a first control signal and a second control signal are generated to control the on / off state of the switch module and the working state of the buck chip, including:

[0031] If the motor speed control instruction is to increase the speed, the first control signal is set to a high level signal and the second control signal is set to a low level control signal to control the switch module to be turned on and the buck chip to stop working;

[0032] If the motor speed control instruction is to reduce the speed, the first control signal is set to a low level signal and the second control signal is set to a high level control signal to control the switch module to turn off and control the buck chip to start working.

[0033] The present invention also provides a computer-readable storage medium on which a computer program is stored, and the program implements the above control method when executed by a processor.

[0034] The present invention also provides an electronic device, comprising:

[0035] one or more processors;

[0036] The storage device is used to store one or more programs, and when the one or more programs are executed by the one or more processors, the one or more processors implement the above-mentioned control method.

[0037] The technical solution of the present invention is applied, and the main controller outputs a first control signal to control the on-off state of the switch module, and outputs a second control signal to control the working state of the buck chip, so as to realize the control of the motor interface and the voltage source being directly connected, or the motor interface and the voltage source being indirectly connected through the buck chip. When the speed needs to be increased, the switch module is controlled to be turned on, and the buck chip stops working, so that the motor interface is directly connected to the voltage source, and then the motor interface inputs the voltage value provided by the voltage source, and then the speed of the motor is increased; when the speed needs to be increased, the switch module is controlled to be turned off, and the buck chip is controlled to be put into operation, so that the motor interface and the voltage source are indirectly connected through the buck chip, and then the motor interface inputs the voltage value provided by the voltage source after the voltage is stepped down, and then the speed of the motor is reduced. It is possible to change the voltage input to the motor through the hardware circuit, without realizing speed regulation by changing the duty cycle of the PWM wave, and without using a speed regulation chip, which can reduce the cost, reduce the interference of the signal, and reduce the probability of control error. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is a structural block diagram of a motor speed control circuit according to an embodiment of the present invention;

[0039] Figure 2is a circuit structure diagram of a switch module according to an embodiment of the present invention;

[0040] Figure 3 A circuit structure diagram of a voltage-reducing chip according to an embodiment of the present invention;

[0041] Figure 4 is a flow chart of a control method according to an embodiment of the present invention;

[0042] Figure 5 FIG. 4 is a schematic diagram of the hardware structure of an electronic device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings, and "multiple" generally includes at least two.

[0045] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0046] It should be understood that although the terms first, second, third, etc. may be used to describe resistors in embodiments of the present invention, these resistors should not be limited to these terms. These terms are only used to distinguish different resistors. For example, without departing from the scope of embodiments of the present invention, a first resistor may also be referred to as a second resistor, and similarly, a second resistor may also be referred to as a first resistor.

[0047] As used herein, the words "if" and "if" may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0048] It should also be noted that the term "includes", "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, so that a commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprising a ..." do not exclude the existence of other identical elements in the commodity or device including the elements.

[0049] The optional embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0050] Example 1

[0051] In the prior art, the speed is regulated by adjusting the duty cycle of PWM, which requires the configuration of a speed regulation chip, increasing the cost, and the PWM signal is easily interfered, resulting in control errors.

[0052] In view of the problem that the motor in the prior art needs to adjust the speed by adjusting the duty cycle of PWM through the speed regulating chip, which is costly and has poor anti-interference ability, this embodiment provides a motor speed control circuit. Figure 1 : is a structural block diagram of a motor speed control circuit according to an embodiment of the present invention, such as Figure 1 As shown, the circuit includes: a switch module 10, whose input end is connected to the voltage source VCC1, whose output end is connected to the motor interface VCC2, whose control end receives a first control signal, and the switch module 10 is turned on or off under the control of a second control signal; a buck chip 20, whose input end is connected to the voltage source VCC1, whose output end is connected to the motor interface VCC2, whose control end receives a second control signal, and the buck chip 20 is put into operation or stops working under the control of the first control signal; a main controller 30, which is used to output the above-mentioned first control signal and the second control signal.

[0053] For example, when the motor speed control instruction is to increase the speed and the motor needs to increase the speed, the first control signal can be set to a high level signal to control the switch module 10 to be turned on, and the second control signal can be set to a low level control signal to control the buck chip 20 to stop working. The buck chip 20 stops working so that the indirect connection between the voltage source VCC1 and the motor interface VCC2 is disconnected, and the switch module 10 is turned on so that the voltage source VCC1 and the motor interface VCC2 are directly connected. The voltage input to the motor interface VCC2 is the voltage provided by the voltage source VCC1, so that the motor runs at a relatively high voltage and the speed is increased.

[0054] When the motor speed control instruction is to reduce the speed and the motor needs to reduce the speed, the first control signal is set to a low level signal to control the switch module 10 to be turned off, and the second control signal is set to a high level control signal to control the buck chip 20 to start working. After the switch module 10 is turned off, the direct connection between the voltage source VCC1 and the motor interface VCC2 is disconnected, and the buck chip 20 is put into operation. The voltage source VCC1 is indirectly connected to the motor interface VCC2 through the buck chip 20, and the voltage input to the motor interface VCC2 is the voltage provided by the voltage source VCC1 after the voltage is stepped down, so that the motor runs at a relatively low voltage and reduces the speed.

[0055] Taking the voltage provided by the voltage source VCC1 as 12V and the voltage reduction range of the step-down chip 20 as 3V as an example, when the motor needs to be adjusted to a high speed, that is, the motor interface VCC2 needs to input a higher voltage value of 12V, at this time, the first control signal FAN1 is high level, so that the switch module 10 is turned on, and the second control signal FAN2 is low level, so that the step-down chip 20 stops working, and the input voltage value of the motor interface VCC2 is 12V provided by the voltage source VCC1; when the motor interface VCC2 needs to be adjusted to a low speed, that is, the motor interface VCC2 needs to input a lower voltage value of 9V, at this time, the first control signal FAN1 is high level, so that the switch module 10 is turned on, and the second control signal FAN2 is low level, so that the step-down chip 20 stops working, and the input voltage value of the motor interface VCC2 is 12V; when the motor interface VCC2 needs to be adjusted to a low speed, that is, the motor interface VCC2 needs to input a lower voltage value of 9V, The first control signal FAN1 is at a low level, turning off the switch module 10, the second control signal FAN2 is at a high level, the buck chip 20 starts working, and the input voltage value of the motor interface VCC2 is the voltage value 12V provided by the voltage source VCC1 and the voltage value 9V after being stepped down by the buck chip; when the motor needs to be adjusted to a stop state, that is, there is no voltage input (0V) to the motor interface VCC2, the first control signal FAN1 is at a low level, the second control signal FAN2 is at a low level, the switch module 10 is turned off, the buck chip 20 stops working, and the direct and indirect connections between the motor interface VCC2 and the voltage source VCC1 are cut off.

[0056] The motor speed control circuit of this embodiment outputs a first control signal through the main controller 30 to control the on-off state of the switch module 10, and outputs a second control signal to control the working state of the buck chip 20, so as to realize the control of direct conduction between the motor interface and the voltage source, or indirect conduction between the motor interface and the voltage source through the buck chip. When the speed needs to be increased, the switch module 10 is controlled to be turned on, and the buck chip 20 stops working, so that the motor interface VCC2 is directly connected to the voltage source, and then the motor interface VCC2 inputs the voltage value provided by the voltage source, thereby increasing the speed of the motor; when the speed needs to be increased, the switch module 10 is controlled to be turned off, and the buck chip 20 is controlled to be put into operation, so that the motor interface VCC2 is indirectly connected to the voltage source through the buck chip, and then the motor interface VCC2 inputs the voltage value provided by the voltage source after the voltage is stepped down, thereby reducing the speed of the motor. It is possible to control the on and off of the switch module 10 and the buck chip 20 by outputting high and low level control signals. There is no need to achieve speed regulation by changing the duty cycle of the PWM wave, and there is no need to use a speed regulation chip. While reducing costs, it can reduce signal interference and reduce the probability of control errors.

[0057] Figure 2 FIG. 1 is a circuit structure diagram of a switch module according to an embodiment of the present invention. In order to control the on-off state of the switch module by a first control signal, as shown in FIG. Figure 2 As shown, the switch module 10 includes: a first controllable switch Q1, a first end of which is connected to the voltage source VCC1 through a first resistor R1 and a second resistor R2 connected in series, a second end of which is connected to a reference ground, and a control end of which is connected to a main controller 30 through a third resistor R3 for receiving a first control signal; a second controllable switch Q2, a first end of which is connected to the voltage source VCC1, a second end of which is connected to a motor interface VCC2, and a control end of which is connected between the first resistor R1 and the second resistor R2.

[0058] In this embodiment, the first controllable switch Q1 is an NPN transistor.

[0059] In order to prevent the voltage of the voltage source VCC1 from flowing to the reference ground, the switch module 10 further includes: a diode D1, whose cathode is connected to the second end of the second controllable switch Q2, and whose anode is connected to the reference ground, and utilizes the unidirectional conduction characteristic of the diode D to prevent the voltage of the voltage source VCC1 from flowing to the reference ground.

[0060] Figure 3: is a circuit structure diagram of a buck chip according to an embodiment of the present invention, the buck chip 20 includes: a first pin VIN, connected to a voltage source VCC1; a second pin EN, the second pin EN is connected to a main controller 30 through a fourth resistor R4, and is used to receive a second control signal, the fourth resistor R4 is also connected to a reference ground through a fifth resistor R5, the second pin EN is an enable pin, when the input is a high level, the buck chip 20 works, and when the input is a low level, the buck chip 20 stops working; a third pin SW, connected to a motor interface VCC2 through an energy storage inductor L1, the energy storage inductor L1 is used to cooperate with the opening and closing of the buck chip to achieve charging and discharging.

[0061] When the motor speed control instruction is to increase the speed and the motor needs to increase the speed, the first control signal is set to a high level signal to control the first controllable switch Q1 to be turned on, and then the second controllable switch Q2 is controlled to be turned on, and then the voltage source VCC1 is controlled to be directly connected to the motor interface VCC2, and the second control signal is set to a low level control signal to control the second pin EN of the buck chip 20 to input a low level, so that the buck chip 20 stops working. The buck chip 20 stops working so that the indirect connection between the voltage source VCC1 and the motor interface VCC2 is disconnected. Since the voltage source VCC1 and the motor interface VCC2 are directly connected, the voltage input to the motor interface VCC2 is the voltage provided by the voltage source VCC1, so that the motor runs at a relatively high voltage and the speed is increased.

[0062] When the motor speed control instruction is to reduce the speed and the motor needs to reduce the speed, the first control signal is set to a low-level signal to control the first controllable switch Q1 to turn off, and then control the second controllable switch Q2 to turn off, and then control the direct connection between the voltage source VCC1 and the motor interface VCC2 to be disconnected, and the second control signal is set to a high-level control signal to control the second pin EN of the buck chip 20 to input a high level, so that the buck chip 20 is put into operation. After the direct connection between the voltage source VCC1 and the motor interface VCC2 is disconnected, the voltage source VCC1 is indirectly connected to the motor interface VCC2 through the buck chip 20, and the voltage input to the motor interface VCC2 is the voltage provided by the voltage source VCC1 after the voltage is stepped down, so that the motor runs at a relatively low voltage and reduces the speed.

[0063] In order to provide the driving voltage required to step down the high-side switch, such as Figure 3 As shown, the buck chip 20 further includes: a fourth pin BOOST, and the fourth pin BOOST is connected to the third pin through a first capacitor C1.

[0064] In order to realize the feedback of the motor interface VCC2 input voltage, such as Figure 3As shown, the buck chip 20 also includes: a fifth pin FB, connected to the motor interface VCC2 through a sixth resistor R6, and the sixth resistor R6 is also connected to the reference ground through a seventh resistor R7. The sixth resistor R6 and the seventh resistor R7 are connected in series to divide the voltage and collect the input voltage of the motor interface VCC2.

[0065] In order to filter the output voltage of the buck chip, the buck chip 20 further includes: a second capacitor C2 and a third capacitor C3, and the second capacitor C2 and the third capacitor C3 are arranged in parallel between the motor interface VCC2 and the reference ground.

[0066] Example 2

[0067] This embodiment provides a motor, including the motor speed control circuit of the above embodiment, for reducing costs and reducing the probability of control errors.

[0068] Example 3

[0069] This embodiment provides a fan, including the motor of the above embodiment, for reducing costs and reducing the probability of control errors.

[0070] Example 4

[0071] This embodiment provides a heat exchange device, including the fan of the above embodiment.

[0072] In some embodiments of the present invention, the heat exchange device includes at least one of the following: an air conditioner, a refrigerator.

[0073] Example 5

[0074] This embodiment provides a control method, which is applied to the above motor speed control circuit. Figure 4 is a flow chart of a control method according to an embodiment of the present invention, as shown in Figure 4 As shown, the control method includes:

[0075] S101, receiving a motor speed control instruction.

[0076] In a specific implementation, the above speed control instruction is generated based on user operation, or automatically generated after certain parameters meet pre-set conditions.

[0077] S102, generating a first control signal and a second control signal in response to a motor speed control instruction to control the on-off state of the switch module and the working state of the buck chip.

[0078] The control method of this embodiment controls the on-off state of the switch module through a first control signal, and controls the working state of the buck chip through a second control signal, thereby controlling the motor interface to be directly connected to the voltage source, or the motor interface to be indirectly connected to the voltage source through the buck chip, thereby controlling the motor input to have a higher voltage or a lower voltage, thereby achieving motor speed regulation. There is no need to achieve speed regulation by changing the duty cycle of the PWM wave, and there is no need to use a speed regulation chip. While reducing costs, it can reduce signal interference and reduce the probability of control errors.

[0079] Specifically, in response to the motor speed control instruction, a first control signal and a second control signal are generated to control the on-off state of the switch module and the working state of the buck chip, including: if the motor speed control instruction is to increase the speed, the first control signal is set to a high-level signal and the second control signal is set to a low-level control signal to control the switch module to be turned on and the buck chip to be stopped; when the buck chip stops working, the indirect connection between the voltage source and the motor interface is disconnected, and the switch module is turned on to directly connect the voltage source and the motor interface, and the voltage input to the motor interface is the voltage provided by the voltage source, so that the motor runs at a relatively high voltage and the speed is increased.

[0080] If the motor speed control instruction is to reduce the speed, the first control signal is set to a low level signal and the second control signal is set to a high level control signal to control the switch module to be turned off and the buck chip to be put into operation. After the switch module is turned off, the direct connection between the voltage source and the motor interface is disconnected, and the buck chip is put into operation. The voltage source is indirectly connected to the motor interface through the buck chip, and the voltage input to the motor interface is the voltage provided by the voltage source after the voltage is stepped down, so that the motor runs at a relatively low voltage and reduces the speed.

[0081] Example 6

[0082] This embodiment provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the control method of the above embodiment is implemented.

[0083] Example 7

[0084] This embodiment provides an electronic device, including:

[0085] one or more processors;

[0086] The storage device is used to store one or more programs, and when the one or more programs are executed by the one or more processors, the one or more processors implement the control method of the above embodiment.

[0087] Figure 5FIG. 1 is a schematic diagram of the hardware structure of an electronic device according to an embodiment of the present invention. Figure 5 As shown, the electronic device includes:

[0088] One or more processors 510 and memory 520, Figure 5 A processor 510 is taken as an example.

[0089] The electronic device may further include: an input device 530 and an output device 540 .

[0090] The processor 510, the memory 520, the input device 530 and the output device 540 may be connected via a bus or other means. Figure 5 The example of connecting through bus is taken in the following.

[0091] The memory 520 is a non-volatile computer-readable storage medium that can be used to store non-volatile software programs, non-volatile computer executable programs and modules, such as program instructions / modules corresponding to the control method in the embodiment of the present invention. The processor 510 executes various functional applications and data processing of the server by running the non-volatile software programs, instructions and modules stored in the memory 520, that is, implementing the above method embodiment.

[0092] The memory 520 may include a program storage area and a data storage area, wherein the program storage area may store an application required for operating the device and at least one function; the data storage area may store data created according to the use of the control method, etc. In addition, the memory 520 may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one disk storage device, a flash memory device, or other non-volatile solid-state storage devices.

[0093] The input device 530 can receive input digital or character information and generate key signal input related to user settings and function control of the electronic device. The output device 540 can include a display device such as a display screen.

[0094] The one or more modules are stored in the memory 520, and when executed by the one or more processors 510, perform the control method in any of the above method embodiments.

[0095] The electronic device can execute the method provided by the embodiment of the present invention, and has the functional modules and beneficial effects corresponding to the execution method. For technical details not described in detail in this embodiment, please refer to the method provided by the embodiment of the present invention.

[0096] The electronic device of the embodiment of the present invention exists in various forms, including but not limited to:

[0097] (1) Mobile communication devices: These devices are characterized by their mobile communication functions and their main purpose is to provide voice and data communications. These terminals include: smart phones (such as iPhone), multimedia phones, functional phones, and low-end phones.

[0098] (2) Ultra-mobile personal computer devices: These devices fall into the category of personal computers, have computing and processing capabilities, and generally also have mobile Internet access features. These terminals include: PDA, MID and UMPC devices, such as iPad.

[0099] (3) Portable entertainment devices: These devices can display and play multimedia content. They include audio and video players (such as iPods), handheld game consoles, e-books, smart toys, and portable car navigation devices.

[0100] (4) Server: A device that provides computing services. The server consists of a processor, hard disk, memory, device bus, etc. The server is similar to a general computer architecture, but because it needs to provide highly reliable services, it has higher requirements in terms of processing power, stability, reliability, security, scalability, and manageability.

[0101] (5) Other electronic devices with data interaction functions, such as televisions, large-screen cars, etc.

[0102] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A motor speed control circuit, characterized in that: The circuit comprises: A switch module, whose input end is connected to a voltage source, whose output end is connected to a motor interface, whose control end receives a first control signal, and the switch module is turned on or off under the control of the second control signal; A step-down chip, whose input end is connected to the voltage source, whose output end is connected to the motor interface, whose control end receives a second control signal, and the step-down chip starts working or stops working under the control of the first control signal; A main controller is used to output the first control signal and the second control signal.

2. The circuit according to claim 1, characterized in that The switch module comprises: A first controllable switch, a first end of which is connected to the voltage source via a first resistor and a second resistor connected in series, a second end of which is connected to a reference ground, and a control end of which is connected to the main controller via a third resistor, for receiving the first control signal; A second controllable switch has a first end connected to the voltage source, a second end connected to the motor interface, and a control end connected between the first resistor and the second resistor.

3. The circuit according to claim 2, characterized in that The switch module also includes: A diode, a cathode of which is connected to the second end of the second controllable switch, and an anode of which is connected to the reference ground.

4. The circuit according to claim 1, characterized in that The step-down chip comprises: A first pin, connected to the voltage source; a second pin, the second pin being connected to the main controller via a fourth resistor and being used to receive the second control signal, the fourth resistor being further connected to a reference ground via a fifth resistor; The third pin is connected to the motor interface through an energy storage inductor.

5. The circuit according to claim 4, characterized in that The step-down chip further includes: A fourth pin, the fourth pin being connected to the third pin via a first capacitor; The fifth pin is connected to the motor interface through a sixth resistor, and the sixth resistor is also connected to a reference ground through a seventh resistor.

6. The circuit according to claim 4, characterized in that The step-down chip further includes: A second capacitor and a third capacitor, wherein the second capacitor and the third capacitor are arranged in parallel between the motor interface and a reference ground.

7. A motor, characterized in that: The invention comprises the motor speed control circuit according to any one of claims 1 to 6.

8. A fan, characterized in that: Comprising the motor as claimed in claim 7.

9. A heat exchange device, characterized in that: Including the fan as described in claim 8.

10. The heat exchange device according to claim 9, characterized in that: The heat exchange equipment includes at least one of the following: an air conditioner, a refrigerator.

11. A control method, applied to the motor speed control circuit according to any one of claims 1 to 6, characterized in that: The control method comprises: Receive motor speed control instructions; A first control signal and a second control signal are generated in response to the motor speed control instruction to control the on-off state of the switch module and the working state of the buck chip.

12. The control method according to claim 11, characterized in that: In response to the motor speed control instruction, a first control signal and a second control signal are generated to control the on / off state of the switch module and the working state of the buck chip, including: If the motor speed control instruction is to increase the speed, the first control signal is set to a high level signal and the second control signal is set to a low level control signal to control the switch module to be turned on and the buck chip to stop working; If the motor speed control instruction is to reduce the speed, the first control signal is set to a low level signal and the second control signal is set to a high level control signal to control the switch module to turn off and control the buck chip to start working.

13. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the control method according to claim 11 or 12 is implemented.

14. An electronic device, characterized in that: include: one or more processors; A storage device for storing one or more programs, when the one or more programs are executed by the one or more processors, enables the one or more processors to implement the control method as claimed in claim 11 or 12.

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