Fan control circuit and electronic equipment

Abstract

The utility model relates to the technical field of heat dissipation of electronic equipment, and provides a fan control circuit which comprises a fan driving circuit, a sensor, an amplifying circuit and a first controller. The sensor is used for collecting wind speed information of the fan and environment temperature information of the fan. The amplifying circuit is used for amplifying the wind speed information collected by the sensor. The first controller is used for conducting analog-to-digital conversion on the environment temperature information collected by the sensor and the amplified wind speed information and sending an analog-to-digital conversion result to the second controller, and the second controller determines a duty ratio control signal used for being output to the fan driving circuit. And the fan driving circuit is used for setting a duty ratio for driving the fan to rotate based on the duty ratio control signal. The second controller is further used for adjusting the duty ratio control signal based on the rotating speed information fed back by the fan driving circuit. According to the fan control circuit, the fan can be accurately controlled, and the heat dissipation instantaneity of equipment is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electronic equipment heat dissipation, and in particular to a fan control circuit and an electronic equipment. BACKGROUND

[0002] Electronic equipment has been widely applied in various fields of daily life, work, study and the like. High temperature is a very key factor affecting the working stability / efficiency of electronic equipment. Therefore, electronic equipment is usually configured with a fan for heat dissipation.

[0003] The existing temperature sensor is generally arranged close to a heat source, and a fan control circuit controls the running state of the fan based on a temperature sensing signal of the temperature sensor. This kind of mode cannot inhibit temperature in the system temperature rising stage, and needs to wait until the temperature sensor detects a critical temperature to trigger the fan control circuit to control cooling, at which time the heat source has discharged a large amount of heat into the system, causing the power loss of the components of the system to increase, and a long time is needed to run the fan for cooling. Utility model content

[0004] In order to solve the problems in the prior art, the present application provides a fan control circuit and an electronic equipment, which can realize accurate control of the fan and improve the instantaneity of equipment heat dissipation.

[0005] The present application provides a fan control circuit, comprising: a fan driving circuit electrically connected to a fan, used for driving the fan to rotate; a sensor used for collecting wind speed information of the fan and environmental temperature information of the fan; an amplification circuit electrically connected to the sensor, used for amplifying the wind speed information collected by the sensor; a first controller electrically connected to the amplification circuit, used for performing analog-to-digital conversion on the environmental temperature information and the amplified wind speed information, obtaining digital sensing information of temperature and wind speed, and sending the digital sensing information of temperature and wind speed to a second controller, so that the second controller determines a duty cycle control signal used for output to the fan driving circuit based on the digital sensing information of temperature and wind speed, and the fan driving circuit is used for setting a duty cycle used for driving the fan to rotate based on the duty cycle control signal; the fan driving circuit is also electrically connected to the second controller, and the fan driving circuit is also used for feeding back rotation speed information of the fan to the second controller, so that the second controller adjusts the duty cycle control signal based on the rotation speed information.

[0006] The fan control circuit can collect the ambient temperature and the fan speed through the sensor, the second controller can control the duty cycle of the fan rotation based on the ambient temperature and the fan speed collected by the sensor, the temperature rise can be inhibited in the system temperature rising stage, the instantaneity of the heat dissipation of the electronic equipment can be improved, and the duty cycle of the fan rotation can be further controlled in a closed loop based on the feedback fan speed information, so that the fan can be accurately controlled.

[0007] In some possible implementation manners, the first controller is configured to send the digital sensing information of the temperature and the speed to the second controller through an Inter-Integrated Circuit (I2C) interface.

[0008] In some possible implementation manners, the first controller comprises a micro control unit (MCU), and the second controller comprises a motherboard heat dissipation management chip.

[0009] In some possible implementation manners, the amplification circuit comprises a first amplification unit, a second amplification unit and a first resistor, an input end of the first amplification unit is electrically connected to a first signal output end of the sensor, and an output end of the first amplification unit is electrically connected to the first controller; an input end of the second amplification unit is electrically connected to a second signal output end of the sensor, and an output end of the second amplification unit is electrically connected to the first controller; one end of the first resistor is electrically connected to the output end of the first amplification unit, and the other end of the first resistor is electrically connected to the output end of the second amplification unit.

[0010] In some possible implementation manners, the first amplification unit comprises a second resistor, one end of the second resistor is electrically connected to the first signal output end of the sensor, a first amplifier comprises a first input end, a second input end and an output end, the first input end of the first amplifier is grounded, the second input end of the first amplifier is electrically connected to the other end of the second resistor, the output end of the first amplifier is electrically connected to one end of the first resistor and the first controller, a third resistor is electrically connected between the second input end and the output end of the first amplifier; the second amplification unit comprises a second amplifier, the second amplifier comprises a first input end, a second input end and an output end, the first input end of the second amplifier is electrically connected to the second signal output end of the sensor, the output end of the second amplifier is electrically connected to the other end of the first resistor and the first controller, a fourth resistor has one end electrically connected to the second input end of the second amplifier and the other end grounded, and a fifth resistor is electrically connected between the second input end and the output end of the second amplifier.

[0011] In some possible implementation manners, the sensor comprises a temperature sensor, the first controller comprises a first analog-digital conversion acquisition pin, a second analog-digital conversion acquisition pin and a third analog-digital conversion acquisition pin, the first analog-digital conversion acquisition pin is electrically connected to the output end of the first amplifier, the second analog-digital conversion acquisition pin is electrically connected to the output end of the second amplifier, and the third analog-digital conversion acquisition pin is electrically connected to the temperature sensor, so that the first controller performs analog-digital conversion on the ambient temperature information.

[0012] In some possible implementation manners, the fan comprises an impeller and a motor driving the rotation of the impeller, and the fan driving circuit comprises a driving chip comprising a power supply pin, a ground pin, a pulse width modulation (PWM) pin and a feedback pin, the power supply pin is used for accessing a power supply voltage, and the ground pin is grounded; a sixth resistor having one end electrically connected to the PWM pin and the other end electrically connected to the motor and the second controller, and being used for outputting a PWM signal to drive the rotation of the motor and feeding back the rotation speed information to the second controller; a first voltage stabilizing diode having a positive electrode grounded and a negative electrode electrically connected to one end of the sixth resistor; a first capacitor having one end electrically connected to the negative electrode of the first voltage stabilizing diode and the other end grounded; a seventh resistor having one end electrically connected to the feedback pin and the other end electrically connected to the second controller, and being used for receiving the duty cycle control signal; a second capacitor having one end electrically connected to the other end of the seventh resistor and the other end grounded; and a second voltage stabilizing diode having a positive electrode grounded and a negative electrode electrically connected to one end of the second capacitor.

[0013] In some possible implementation manners, the fan driving circuit further comprises a voltage input unit, the voltage input unit comprises a first diode having a positive electrode used for accessing the power supply voltage and a negative electrode electrically connected to the power supply pin; a second diode connected in parallel with the first diode; a third diode having a positive electrode used for accessing the power supply voltage and a negative electrode electrically connected to a voltage reduction circuit, the voltage reduction circuit being used for reducing and converting the power supply voltage to supply power to the first controller; a third voltage stabilizing diode having a positive electrode grounded and a negative electrode electrically connected to the negative electrode of the first diode; an eighth resistor having one end electrically connected to the negative electrode of the third voltage stabilizing diode; a third capacitor having one end electrically connected to the other end of the eighth resistor and the other end grounded; and a fourth capacitor having one end electrically connected to one end of the eighth resistor and the other end grounded.

[0014] In some possible implementations, the sensor is fixedly connected to one side of the fan and located above an air outlet of the fan, and the sensor comprises a hot-wire anemometer.

[0015] The application further provides an electronic device comprising a fan, a second controller and the fan control circuit, wherein the fan and the second controller are electrically connected to the fan control circuit.

[0016] The electronic device can collect the ambient temperature and the fan speed through the sensor, and the second controller can control the duty cycle of the fan rotation based on the ambient temperature and the fan speed collected by the sensor, so that the temperature rise can be inhibited in the device system temperature rising stage, the instantaneity of the electronic device heat dissipation is improved, and the duty cycle of the fan rotation is further closed-loop controlled based on the feedback fan speed information, so that the fan is precisely controlled. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 FIG. 1 is a module structure schematic diagram of an embodiment of the electronic device of the application.

[0018] Figure 2 FIG. 2 is a module structure schematic diagram of an embodiment of the fan control circuit of the application.

[0019] Figure 3 FIG. 3 is a structure schematic diagram of a sensor installation position of an embodiment of the application.

[0020] Figure 4 FIG. 4 is a block structure schematic diagram of another embodiment of the fan control circuit of the application.

[0021] Figure 5 FIG. 5 is a circuit schematic diagram of an embodiment of the Wheatstone bridge circuit of the application.

[0022] Figure 6 FIG. 6 is a circuit schematic diagram of an embodiment of the fan control circuit of the application.

[0023] Figure 7 FIG. 7 is a circuit schematic diagram of another embodiment of the fan control circuit of the application.

[0024] Main element symbol explanation: electronic device - 100; fan - 10; fan control circuit - 20; fan driving circuit - 201; sensor - 202; amplification circuit - 203; first controller - 204; step-down circuit - 205; second controller - 30; first amplification unit 2031; second amplification unit 2032; first to thirteenth resistors R1~R13; first to third fixed resistors R21~R23; variable hot wire resistor R24; amplifier OP11; first amplifier - OP1; second amplifier - OP2; impeller - 2021; motor - 2022; driving chip - U1; step-down chip - U2; first to third zener diodes ZD1~ZD3; first to twelfth capacitors C1~C12; first to third diodes D1~D3; inductor L; thermistor RT.

[0025] The following detailed description will further describe the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0026] The following description will refer to the accompanying drawings to more fully describe the present application. The drawings show exemplary embodiments of the present application. However, the present application can be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth herein. These exemplary embodiments are provided so that this application will be thorough and complete, and will fully convey the scope of the present application to those skilled in the art. Like reference numerals refer to like elements throughout.

[0027] The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. Furthermore, to the extent that the terms "including", "includes", "having", "has", "a", "an", "one" or "said one" are used in this specification and / or claims, they are intended to be inclusive (meaning that there can be additional items) and / or they are intended to be quantitatively-satisfied by at least the recited item (meaning that any additional, non-recited items are not excluded).

[0028] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0029] It can be understood that the connection relationship described in the present application refers to direct or indirect connection. For example, A is connected with B, which can be that A is directly connected with B, or A is indirectly connected with B through one or more other electrical components. For example, A can be directly connected with C, and C is directly connected with B, so that A is connected with B through C. It can also be understood that "A is connected with B" described in the present application can be that A is directly connected with B, or A is indirectly connected with B through one or more other electrical components.

[0030] In the description of the present application, "first", "second" and the like are only used to distinguish different objects, and do not limit the quantity and execution order, and "first", "second" and the like do not necessarily mean different. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion.

[0031] The following will describe exemplary embodiments in conjunction with the accompanying drawings. It should be noted that the components depicted in the accompanying drawings are not necessarily shown to scale; and the same or similar components will be assigned the same or similar reference numerals or similar technical terms.

[0032] Please see Figure 1 An embodiment of the present application provides an electronic device 100. The electronic device 100 can include a fan 10, a fan control circuit 20 and a second controller 30. The fan control circuit 20 is electrically connected with the fan 10 and the second controller 30 respectively, and the fan control circuit 20 and the second controller 30 are used together to control the running state of the fan 10. The running state includes but is not limited to starting, stopping, speed adjustment and the like.

[0033] It can be understood that the structure shown in the embodiment does not constitute a specific limitation on the electronic device 100. In other embodiments, the electronic device 100 can include more components than shown. For example, the electronic device 100 can further include a mainboard circuit, a power supply circuit and the like. The second controller 30 can be arranged on the mainboard circuit.

[0034] In some embodiments, the electronic device 100 can be an electronic device with heat dissipation requirements, for example, the electronic device 100 can be a desktop computer host, an all-in-one computer, a notebook computer, a server, a projector and the like.

[0035] Please see Figure 2 An embodiment of the present application provides a fan control circuit 20. The fan control circuit 20 can include a fan driving circuit 201, a sensor 202, an amplification circuit 203 and a first controller 204. The fan driving circuit 201 is electrically connected to the fan 10, and is used to drive the fan 10 to rotate. For example, the fan 10 can include an impeller and a motor, and the fan driving circuit 201 can be electrically connected to the motor, and drive the motor to rotate, thereby driving the impeller to rotate.

[0036] The sensor 202 is configured to collect the wind speed information of the fan 10 and the ambient temperature information of the fan 10. The amplifier circuit 203 is electrically connected to the sensor 202, and the amplifier circuit 203 is configured to amplify the wind speed information collected by the sensor 202. The ambient temperature information can not need to be amplified.

[0037] In some embodiments, the sensor 202 can be fixedly arranged on one side of the fan 10 and above the air outlet of the fan 10, so as to accurately collect the wind speed information of the fan 10 and the ambient temperature information of the fan 10. The installation position of the sensor 202 can also be set according to the actual number of sensors and the data collection requirements, which is not limited in the embodiments of the present application.

[0038] The first controller 204 is electrically connected to the amplifier circuit 203 and the second controller 30. The first controller 204 is configured to perform analog-to-digital conversion on the ambient temperature information and the amplified wind speed information, to obtain digital sensing information of the temperature and the wind speed, and to send the digital sensing information of the temperature and the wind speed to the second controller 30. For example, the first controller 204 can send the digital sensing information of the temperature and the wind speed to the second controller 30 through an Inter-Integrated Circuit (I2C) interface. It can be understood that the first controller 204 can also send the digital sensing information of the temperature and the wind speed to the second controller 30 through other communication interfaces, which is not limited in the embodiments of the present application.

[0039] The second controller 30 is electrically connected to the fan driving circuit 201, and the second controller 30 is configured to determine a duty cycle control signal for output to the fan driving circuit 201 based on the digital sensing information of the temperature and the wind speed. The fan driving circuit 201 is configured to set a duty cycle for driving the fan to rotate based on the duty cycle control signal.

[0040] The fan driving circuit 201 is also configured to feed back the rotation speed information of the fan 10 to the second controller 30, and the second controller 30 is also configured to adjust the duty cycle control signal output to the fan driving circuit 201 based on the rotation speed information, to realize closed-loop control of the fan 10.

[0041] In some embodiments, the fan driving circuit 201 can be powered by configuring a power supply voltage. For example, the power supply voltage can be provided by a mainboard circuit, and the power supply voltage can be a 12V direct current voltage. The fan control circuit 20 can also include a voltage reduction circuit 205, which can be configured to reduce and convert the power supply voltage to obtain a first voltage. For example, the first voltage can be used to power the first controller 204 and the like. The voltage value of the first voltage can be 3.3V, 5V, etc.

[0042] In some embodiments, the first controller 204 can include a micro controller unit (MCU) or other chip with analog-to-digital conversion function, and the second controller 30 can include a motherboard heat dissipation management chip. That is, the second controller 30 can be arranged on the motherboard circuit and implemented by multiplexing the controller in the motherboard circuit to save the chip cost of the electronic device. For example, the second controller can be a power supply management chip, an embedded controller chip (EC), a super input output chip (Super I / O), etc.

[0043] The fan control circuit described above can accurately collect the ambient temperature and the fan speed by fixing the sensor to one side of the fan and above the air outlet of the fan, and the second controller can control the duty cycle of the fan rotation based on the ambient temperature and the fan speed collected by the sensor, so that the temperature rise can be inhibited in the system temperature rising stage, the instantaneity of the heat dissipation of the electronic device is improved, and the duty cycle of the fan rotation is further controlled in a closed loop based on the feedback fan speed information, so that the fan is accurately controlled.

[0044] Please refer to Figure 3 The installation schematic diagram of the sensor 202 provided by an embodiment of the present application is shown in Figure 3 (a) is a top view of the fan 10, Figure 3 (b) is a bottom view of the fan 10, Figure 3 (c) is a front view of the fan 10. The sensor 202 is fixedly installed on one side edge of the fan 10 through the sensor support 101.

[0045] The sensor support 101 can be integrally formed with the side edge of the fan 10 or fixed to the side edge of the fan 10 by means of locking screws / buckles, etc. The sensor 202 can be fixed in the sensor support 101 by means of interference fit, point gluing, etc.

[0046] In some embodiments, the sensor 202 can be located directly above the air outlet of the fan 10 and as close to the outer diameter of the fan blade as possible. The size of the sensor support 101 can be matched with the size of the sensor 202, which is not limited in the embodiments of the present application. For example, the length, width and height of the sensor support 101 are 27.30 mm x 18.00 mm x 18.35 mm, respectively.

[0047] In some embodiments, the speed regulation of the fan 10 can be divided into four modes: a low temperature segment, a normal temperature segment, a high temperature segment and an overheat protection segment.

[0048] In the low temperature section, the temperature is low, the system heat dissipation demand is small, the fan rotating speed can keep low level. The control strategy can be: the fan rotating speed is constant as a small preset value, to realize the effect of reducing noise and saving energy.

[0049] In the normal temperature section, the temperature is in the normal range, the fan rotating speed can be linearly adjusted according to the temperature change. The control strategy can be: using a quadratic equation with a large slope to define the relationship between the fan rotating speed and the temperature, to realize keeping the system temperature constant.

[0050] In the high temperature section, the temperature is high, the system heat dissipation demand increases sharply, the fan rotating speed needs to be quickly raised, the control strategy can be: using a quadratic equation with a curved upward curve to define the relationship between the fan rotating speed and the temperature, to realize rapid cooling.

[0051] In the overheating protection section, the temperature is too high, the fan runs at the maximum speed, and the alarm (additional sound / light alarm unit) is triggered. The control strategy can be: the fan rotating speed is constant as a preset maximum value, to realize protecting the system.

[0052] For example, the low temperature section is below 20℃, the fan rotating speed is constant as a small preset value. The normal temperature section is 20℃-35℃, the quadratic equation is: Y=31.25X 2 -33.75X+531.2. Wherein, Y is the fan rotating speed, X is the temperature. The high temperature section is: 35℃-55℃, the quadratic equation is: Y=125X 2 -15X+875. The overheating protection section is above 55℃, the fan rotating speed is constant as a preset maximum value.

[0053] Please refer to Figure 4 , the amplification circuit 203 can include a first amplification unit 2031, a second amplification unit 2032 and a first resistor R1. The input end of the first amplification unit 2031 is electrically connected to the first signal output end of the sensor 202, and the output end of the first amplification unit 2031 is electrically connected to the first controller 204. The input end of the second amplification unit 2032 is electrically connected to the second signal output end of the sensor 202, and the output end of the second amplification unit 2032 is electrically connected to the first controller 204. One end of the first resistor R1 is electrically connected to the output end of the first amplification unit 2031, and the other end is electrically connected to the output end of the second amplification unit 2032. The embodiment of the present application realizes the function of bridge operational amplifier by the first amplification unit 2031, the second amplification unit 2032 and the first resistor R1, and realizes the amplification processing of the wind speed information collected by the sensor 202.

[0054] Please refer to Figure 5 , the embodiment of the present application provides a circuit diagram of a Wheatstone bridge circuit for processing the signal output by the sensor 202.

[0055] Sensor 202 may include a hot-wire anemometer. The hot-wire anemometer determines wind speed by measuring the cooling rate of a heating element in the airflow. The hot-wire anemometer has a built-in temperature sensor and can transmit temperature and temperature difference signals using its circuit design. The transmitted temperature signal (i.e., ambient temperature information) can be directly transmitted to the first controller 204 for analog-to-digital conversion, and the transmitted temperature difference signal can be input to the amplifier circuit 203 for amplification, thus amplifying the sensed wind speed information. For example, the hot-wire anemometer can use a Wheatstone bridge circuit for signal processing, and the processed signal is then input to the amplifier circuit 203 for further amplification.

[0056] like Figure 5 As shown, the Wheatstone bridge circuit may include a first fixed resistor R21, a second fixed resistor R22, a third fixed resistor R23, a variable hot-wire resistor R24, and an amplifier OP11. The first signal output terminal and the second signal output terminal of the sensor 202 may be electrically connected to one end of the first fixed resistor R21 and one end of the second fixed resistor R22, respectively.

[0057] Please see Figure 6 The following is a circuit diagram of a fan control circuit 20 provided in one embodiment of this application.

[0058] The first amplification unit 2031 may include a second resistor R2, a first amplifier OP1, and a third resistor R3. One end of the second resistor R2 is electrically connected to the first signal output terminal I+ of the sensor 202. The first amplifier OP1 includes a first input terminal, a second input terminal, and an output terminal. The first input terminal of the first amplifier OP1 is grounded, the second input terminal of the first amplifier OP1 is electrically connected to the other end of the second resistor R2, and the output terminal of the first amplifier OP1 is electrically connected to one end of the first resistor R1 and the first analog-to-digital conversion acquisition pin PB1 of the first controller 204. The third resistor R3 is electrically connected between the second input terminal and the output terminal of the first amplifier OP1. The second amplification unit 2032 may include a second amplifier OP2, a fourth resistor R4, and a fifth resistor R5. The second amplifier OP2 includes a first input terminal, a second input terminal, and an output terminal. The first input terminal of the second amplifier OP2 is electrically connected to the second signal output terminal I- of the sensor 202, and the output terminal of the second amplifier OP2 is electrically connected to the other end of the first resistor R1 and the second analog-to-digital conversion acquisition pin PB2 of the first controller 204. One end of the fourth resistor R4 is electrically connected to the second input terminal of the second amplifier OP2, and the other end of the fourth resistor R4 is grounded. The fifth resistor R5 is electrically connected between the second input terminal and the output terminal of the second amplifier OP2.

[0059] In some embodiments, the first input terminal of the first amplifier OP1 and the first input terminal of the second amplifier OP2 can be positive input terminals, and the second input terminal of the first amplifier OP1 and the second input terminal of the second amplifier OP2 can be negative input terminals.

[0060] It can be understood that the circuit structure of the first amplification unit 2031 and the second amplification unit 2032 can also be transformed according to actual amplification multiple requirements, and is not limited to the above circuit structure. The above circuit structure is only an example.

[0061] The fan 10 can include an impeller 1001 and a motor 1002 driving the impeller 1001 to rotate. The fan driving circuit 201 can include a driving chip U1, a sixth resistor R6, a first zener diode ZD1, a first capacitor C1, a seventh resistor R7, a second capacitor C2, and a second zener diode ZD2.

[0062] The driving chip U1 can include a first output pin OUT1, a second output pin OUT2, a power supply pin VDD, a ground pin GND, a pulse width modulation PWM pin PWM1, and a feedback pin FG1. The power supply pin VDD is used to access a power supply voltage VCC1, and the ground pin GND is grounded. For example, the power supply voltage VCC1 can be a direct current voltage of 12V.

[0063] One end of the sixth resistor R6 is electrically connected to the PWM pin PWM1 of the driving chip U1, and the other end of the sixth resistor R6 is electrically connected to the motor 1002, for outputting a PWM signal to drive the motor 1002 to rotate. The other end of the sixth resistor R6 is also electrically connected to the feedback pin FG2 of the second controller 30, to feed back the speed information to the second controller 30. The positive electrode of the first zener diode ZD1 is grounded, and the negative electrode of the first zener diode ZD1 is electrically connected to one end of the sixth resistor R6. One end of the first capacitor C1 is electrically connected to the negative electrode of the first zener diode ZD1, and the other end of the first capacitor C1 is grounded.

[0064] One end of the seventh resistor R7 is electrically connected to the feedback pin FG1 of the driving chip U1, and the other end of the seventh resistor R7 is electrically connected to the PWM pin PWM2 of the second controller 30, for receiving the duty cycle control signal output by the second controller 30. One end of the second capacitor C2 is electrically connected to the other end of the seventh resistor R7, and the other end of the second capacitor C2 is grounded. The positive electrode of the second zener diode ZD2 is grounded, and the negative electrode of the second zener diode ZD2 is electrically connected to one end of the second capacitor C2.

[0065] Sensor 202 may also include an eighth resistor R8 and a thermistor RT. One end of the eighth resistor R8 is used to receive the first voltage VCC2, and the other end of the eighth resistor R8 is electrically connected to one end of the thermistor RT, the other end of the thermistor RT being grounded. For example, sensor 202 is a hot-wire anemometer, which has a built-in temperature sensor, and the temperature sensor can be composed of the eighth resistor R8 and the thermistor RT.

[0066] In some embodiments, the thermistor RT can be a thermistor with a negative temperature coefficient or a thermistor with a positive temperature coefficient.

[0067] In some embodiments, the common connection terminal of the eighth resistor R8 and the thermistor RT can also serve as the third signal output terminal of the sensor 202. The ambient temperature information is output from the third signal output terminal to the third analog-to-digital conversion acquisition pin PB3 of the first controller 204, so that the first controller 204 can perform analog-to-digital conversion on the ambient temperature information.

[0068] It is understood that the circuit structure of the fan drive circuit 201 can be modified according to requirements and is not limited to the circuit structure described above. The circuit structure described above is only an example. For example, a capacitor can be added in parallel with the first capacitor C1, and a capacitor can be added in parallel with the second capacitor C2.

[0069] In some embodiments, the driver chip U1 and the first controller 204 can be electrically connected to the motherboard circuit via the connector COM, that is, the driver chip U1 and the first controller 204 can be electrically connected to the second controller 30 via the connector COM.

[0070] like Figure 7 As shown, the fan drive circuit 201 also includes a voltage input unit 2011. The voltage input unit 2011 may include a first diode D1, a second diode D2, a third diode D3, a third Zener diode ZD3, a ninth resistor R9, a third capacitor C3, and a fourth capacitor C4.

[0071] The anode of the first diode D1 is connected to the power supply voltage VCC1, and the cathode of the first diode D1 is electrically connected to the power supply pin VDD of the driver chip U1. The second diode D2 is connected in parallel with the first diode D1, thereby increasing the circuit's overcurrent capability. The anode of the third diode D3 is electrically connected to the anode of the first diode D1, and the cathode of the third diode D3 is electrically connected to the buck converter 205 to power the buck converter 205. The anode of the third Zener diode ZD3 is grounded, and the cathode of the third Zener diode ZD3 is electrically connected to the cathode of the first diode D1. One end of the ninth resistor R9 is electrically connected to the cathode of the third Zener diode ZD3. One end of the third capacitor C3 is electrically connected to the other end of the ninth resistor R9, and the other end of the third capacitor C3 is grounded. One end of the fourth capacitor C4 is electrically connected to one end of the ninth resistor R9, and the other end of the fourth capacitor C4 is grounded.

[0072] It is understood that the circuit structure of the voltage input unit 2011 can be modified according to requirements and is not limited to the circuit structure described above. The circuit structure described above is only an example. For example, the second diode D2 and the fourth capacitor C4 can be omitted.

[0073] like Figure 7 As shown, the step-down circuit 205 can be used to step down the power supply voltage VCC1 to obtain a first voltage VCC2. The first voltage VCC2 can be used to power the first controller 204, etc. The step-down circuit 205 may include a step-down chip U2, fifth to twelfth capacitors C5~C12, tenth to thirteenth resistors R10~R13, and inductor L.

[0074] The voltage reduction chip U2 includes a first end to a sixth end. The first end of the voltage reduction chip U2 is electrically connected to a negative electrode of the third diode D3. One end of the fifth capacitor C5 is electrically connected to the negative electrode of the third diode D3. The other end of the fifth capacitor C5 is grounded. One end of the sixth capacitor C6 is electrically connected to the one end of the fifth capacitor C5. The other end of the sixth capacitor C6 is grounded. One end of the seventh capacitor C7 is electrically connected to the one end of the sixth capacitor C6 and the first end of the voltage reduction chip U2. The other end of the seventh capacitor C7 is grounded. The second end of the voltage reduction chip U2 is electrically connected to one end of the inductor L. The other end of the inductor L is used to output the first voltage VCC2. The third end of the voltage reduction chip U2 is grounded. The fourth end of the voltage reduction chip U2 is electrically connected to one end of the tenth resistor R10. The other end of the tenth resistor R10 is electrically connected to one end of the eighth capacitor C8. The other end of the eighth capacitor C8 is electrically connected to the one end of the inductor L. The fifth end of the voltage reduction chip U2 is electrically connected to one end of the eleventh resistor R11. The other end of the eleventh resistor R11 is electrically connected to the one end of the fifth capacitor C5. The sixth end of the voltage reduction chip U2 is electrically connected to one end of the twelfth resistor R12 and one end of the thirteenth resistor R13. The other end of the twelfth resistor R12 is electrically connected to the other end of the inductor L. The other end of the thirteenth resistor R13 is grounded. The ninth capacitor C9 is connected in parallel with the twelfth resistor R12.

[0075] One end of the tenth capacitor C10 is electrically connected to the other end of the inductor L. The other end of the tenth capacitor C10 is grounded. One end of the eleventh capacitor C11 is electrically connected to the one end of the tenth capacitor C10. The other end of the eleventh capacitor C11 is grounded. One end of the twelfth capacitor C12 is electrically connected to the one end of the eleventh capacitor C11. The other end of the twelfth capacitor C12 is grounded.

[0076] In some embodiments, the first voltage VCC2 can be used to supply power for the first controller 204 and the like. The voltage value of the first voltage VCC2 can be 3.3V, 5V, or the like.

[0077] It can be understood that the circuit structure of the voltage reduction circuit 205 can also be deformed according to requirements, and is not limited to the above-described circuit structure. For example, the seventh capacitor C7, the twelfth capacitor C12, and the like can be omitted.

[0078] In the foregoing, the specific embodiments of the present application are described with reference to the accompanying drawings. However, those skilled in the art can understand that various changes and replacements can be made to the specific embodiments of the present application without departing from the spirit and scope of the present application. These changes and replacements are within the scope defined by the present application.

Claims

1. A fan control circuit, characterized by, The fan control circuit comprises: a fan driving circuit electrically connected to the fan and configured to drive the fan to rotate; a sensor configured to collect wind speed information of the fan and ambient temperature information in which the fan is located; an amplification circuit electrically connected to the sensor and configured to amplify the wind speed information collected by the sensor; a first controller electrically connected to the amplification circuit, configured to perform analog-to-digital conversion on the ambient temperature information and the amplified wind speed information to obtain digital sensing information of temperature and wind speed, and send the digital sensing information of temperature and wind speed to a second controller, so that the second controller determines a duty cycle control signal for output to the fan driving circuit based on the digital sensing information of temperature and wind speed, and the fan driving circuit is configured to set a duty cycle for driving the fan to rotate based on the duty cycle control signal; the fan driving circuit is also electrically connected to the second controller, and the fan driving circuit is further configured to feed back the rotating speed information of the fan to the second controller, so that the second controller adjusts the duty cycle control signal based on the rotating speed information.

2. The fan control circuit of claim 1, wherein, The first controller is configured to send the digital sensing information of temperature and wind speed to the second controller through an inter-integrated circuit (I2C) bus interface.

3. The fan control circuit of claim 1, wherein, The first controller comprises a micro control unit (MCU), and the second controller comprises a mainboard heat dissipation management chip.

4. The fan control circuit of claim 1, wherein, The amplification circuit comprises a first amplification unit, a second amplification unit and a first resistor, an input end of the first amplification unit is electrically connected to a first signal output end of the sensor, and an output end of the first amplification unit is electrically connected to the first controller; an input end of the second amplification unit is electrically connected to a second signal output end of the sensor, and an output end of the second amplification unit is electrically connected to the first controller; one end of the first resistor is electrically connected to the output end of the first amplification unit, and the other end of the first resistor is electrically connected to the output end of the second amplification unit.

5. The fan control circuit of claim 4, wherein, The first amplification unit comprises: a second resistor having one end electrically connected to the first signal output end of the sensor; a first amplifier comprising a first input end, a second input end and an output end, the first input end of the first amplifier is grounded, the second input end of the first amplifier is electrically connected to the other end of the second resistor, and the output end of the first amplifier is electrically connected to one end of the first resistor and the first controller; a third resistor electrically connected between the second input end and the output end of the first amplifier; The second amplification unit comprises: a second amplifier comprising a first input end, a second input end and an output end, the first input end of the second amplifier is electrically connected to the second signal output end of the sensor, and the output end of the second amplifier is electrically connected to the other end of the first resistor and the first controller; a fourth resistor having one end electrically connected to the second input end of the second amplifier and the other end grounded; a fifth resistor electrically connected between the second input end and the output end of the second amplifier.

6. The fan control circuit of claim 5, wherein, The sensor comprises a temperature sensor, the first controller comprises a first analog-digital conversion acquisition pin, a second analog-digital conversion acquisition pin and a third analog-digital conversion acquisition pin, the first analog-digital conversion acquisition pin is electrically connected to the output end of the first amplifier, the second analog-digital conversion acquisition pin is electrically connected to the output end of the second amplifier, and the third analog-digital conversion acquisition pin is electrically connected to the temperature sensor, so that the first controller performs analog-digital conversion on the ambient temperature information.

7. The fan control circuit of claim 1, wherein, The fan comprises an impeller and a motor for driving the impeller to rotate, and the fan driving circuit comprises: a driving chip comprising a power supply pin, a ground pin, a pulse width modulation (PWM) pin and a feedback pin, the power supply pin is used for connecting a power supply voltage, and the ground pin is grounded; a sixth resistor having one end electrically connected to the PWM pin and the other end electrically connected to the motor and the second controller, and being used for outputting a PWM signal to drive the motor to rotate and feeding back the rotating speed information to the second controller; a first voltage stabilizing diode, a positive electrode of the first voltage stabilizing diode being grounded, and a negative electrode of the first voltage stabilizing diode being electrically connected to one end of the sixth resistor; a first capacitor having one end electrically connected to the negative electrode of the first voltage stabilizing diode and the other end grounded; a seventh resistor having one end electrically connected to the feedback pin and the other end electrically connected to the second controller, and being used for receiving the duty cycle control signal; a second capacitor having one end electrically connected to the other end of the seventh resistor and the other end grounded; a second voltage stabilizing diode, a positive electrode of the second voltage stabilizing diode being grounded, and a negative electrode of the second voltage stabilizing diode being electrically connected to one end of the second capacitor.

8. The fan control circuit of claim 7, wherein, The fan driving circuit further comprises a voltage input unit, and the voltage input unit comprises: a first diode, a positive electrode of the first diode being used for connecting the power supply voltage, and a negative electrode of the first diode being electrically connected to the power supply pin; a second diode connected in parallel with the first diode; a third diode, a positive electrode of the third diode being used for connecting the power supply voltage, and a negative electrode of the third diode being electrically connected to a voltage reduction circuit, the voltage reduction circuit being used for reducing and converting the power supply voltage to supply power to the first controller; a third voltage stabilizing diode, a positive electrode of the third voltage stabilizing diode being grounded, and a negative electrode of the third voltage stabilizing diode being electrically connected to the negative electrode of the first diode; an eighth resistor having one end electrically connected to the negative electrode of the third voltage stabilizing diode; a third capacitor having one end electrically connected to the other end of the eighth resistor and the other end grounded; a fourth capacitor having one end electrically connected to one end of the eighth resistor and the other end grounded.

9. The fan control circuit of any one of claims 1 to 8, wherein, The sensor is fixedly connected to one side of the fan and located above an air outlet of the fan, and the sensor comprises a hot-wire anemometer.

10. An electronic device, comprising: The fan, the second controller and the fan control circuit according to any one of claims 1 to 9 are electrically connected to each other.

Images