Fan driving circuit and fan control assembly

Abstract

The utility model discloses a fan driving circuit and a fan control assembly, and relates to the technical field of fan control. The fan driving circuit comprises a first signal input end, a power input circuit, a fan interface, a PWM input circuit and a PWM control circuit. Wherein the power supply input circuit is used for inputting external power supply voltage, and the fan interface is used for being connected with a three-wire / four-wire fan. The PWM input circuit is used for outputting a corresponding PWM control signal according to a PWM signal input by the first signal input end when the fan interface is connected with the four-wire fan so as to adjust the rotating speed of the four-wire fan. The PWM control circuit is used for controlling the conduction state between the grounding pin of the fan interface and the ground according to a PWM signal input by the first signal input end when the fan interface is connected with the three-wire fan, so that the average input voltage of the three-wire fan is adjusted, and therefore the rotating speed of the three-wire fan is adjusted. Therefore, the rotating speed adjusting device can be compatible with rotating speed adjustment of a three-wire fan and a four-wire fan.

Description

TECHNICAL FIELD

[0001] The utility model relates to fan control technical field, especially a fan drive circuit and fan control assembly. BACKGROUND

[0002] With the continuous improvement of electronic equipment performance, the requirement of heat dissipation system also becomes more and more strict. As an important part of the heat dissipation fan, its efficiency and reliability directly affect the stability and service life of the system. The heat dissipation fan on the market mainly includes three-wire fan and four-wire fan. The speed regulation of three-wire fan is realized by changing voltage, usually requiring voltage conversion using digital-to-analog conversion chip (DAC), resulting in a relatively complex circuit structure. Four-wire fan adjusts the speed through PWM control (pulse width modulation) signal, and the circuit structure is relatively simple.

[0003] However, the existing fan drive circuit can usually only support one type of fan, and cannot be compatible with the use of three-wire and four-wire fans. This leads to the need to customize the drive circuit according to the fan type when designing the heat dissipation system. Due to the difference in fan type, the system often needs to redesign the drive circuit when replacing the fan or upgrading, which increases the development cost and reduces the flexibility of the system. SUMMARY

[0004] The main purpose of the utility model is to provide a fan drive circuit, which aims to be compatible with the speed regulation of three-wire fan and four-wire fan.

[0005] To achieve the above purpose, the fan drive circuit provided by the utility model comprises:

[0006] The first signal input end is used for inputting the PWM signal;

[0007] The power input circuit is connected with the external power input end at the power input end of the power input circuit, and the ground end of the power input circuit is grounded; the power input circuit is used for inputting external power voltage;

[0008] The fan interface has a power pin, a ground pin and a control pin, the power pin of the fan interface is connected with the first power end of the power input circuit, and the ground pin of the fan interface is connected with the second power end of the power input circuit; the fan interface is used for connecting three-wire fan or four-wire fan;

[0009] a PWM input circuit, an input end of the PWM input circuit being connected with the first signal input end, an output end of the PWM input circuit being connected with a control pin of the fan interface, and a power supply end of the PWM input circuit being connected with the first power supply end of the power supply input circuit; the PWM input circuit is configured to output a corresponding PWM control signal according to the PWM signal when the fan interface is connected with a four-wire fan;

[0010] a PWM control circuit, a controlled end of the PWM control circuit being connected with the first signal input end, a first end of the PWM control circuit being connected with a ground pin of the fan interface, and a second end of the PWM control circuit being grounded; the PWM control circuit is configured to control a conduction state between the ground pin of the fan interface and the ground according to the PWM signal when the fan interface is connected with a three-wire fan, so as to adjust a size of an average input voltage of the three-wire fan.

[0011] In an embodiment, the fan driving circuit further comprises a control interface, the control interface having a power supply pin, a ground pin, a detection pin and a control pin; the power supply pin of the control interface is connected with an external power supply input end, and the ground pin of the control interface is grounded; wherein the control pin of the control interface is the first signal input end.

[0012] the fan interface further has a detection pin, the detection pin of the fan interface being connected with the detection pin of the control interface, and the detection pin of the fan interface being configured to input a detection signal; the detection signal is configured to indicate rotation speed information of the fan.

[0013] In an embodiment, the PWM control circuit comprises a first switch tube, a controlled end of the first switch tube being connected with the first signal input end, a first end of the first switch tube being connected with the ground pin of the fan interface, and a second end of the first switch tube being grounded.

[0014] In an embodiment, the first switch tube is an NMOS tube, and the PWM control circuit further comprises a first resistor, one end of the first resistor being connected with the first signal input end, the other end of the first resistor being connected with a gate of the NMOS tube, a drain of the NMOS tube being connected with the ground pin of the fan interface, and a source of the NMOS tube being grounded.

[0015] In an embodiment, the PWM input circuit comprises a second resistor and a third resistor, one end of the second resistor being connected with the first power supply end of the power supply input circuit, the other end of the second resistor and one end of the third resistor being connected with the first signal input end, and the other end of the third resistor being connected with the control pin of the fan interface.

[0016] In an embodiment, the power input circuit comprises a first magnetic bead and a second magnetic bead, one end of the first magnetic bead is connected with an external power input end, the other end of the first magnetic bead is connected with a power pin of the fan interface; one end of the second magnetic bead is connected with the power pin of the fan interface, and the other end of the second magnetic bead is grounded.

[0017] In an embodiment, the power input circuit further comprises a first capacitor and a second capacitor; wherein one end of the first capacitor is connected with one end of the first magnetic bead, and the other end of the first capacitor is grounded; one end of the second capacitor is connected with the other end of the first magnetic bead, and the other end of the second capacitor is grounded.

[0018] The utility model also proposes a fan control assembly, including fan drive circuit as above, the fan control assembly further includes:

[0019] The controller is connected with the control interface of the fan drive circuit, and the controller is used for adjusting the duty cycle of the output PWM signal according to the detection signal.

[0020] The fan is connected with the fan interface of the fan drive circuit.

[0021] In an embodiment, the fan is a three-wire fan or a four-wire fan.

[0022] The utility model technical scheme adopts a fan drive circuit, which comprises a first signal input end, a power input circuit, a fan interface, a PWM input circuit and a PWM control circuit. The power input circuit can input an external power voltage. The fan interface can be connected with a three-wire fan or a four-wire fan. The PWM input circuit can output a corresponding PWM control signal according to a PWM signal when the fan interface is connected with a four-wire fan, so as to adjust the rotating speed of the four-wire fan. The PWM control circuit can control the conduction state of the ground pin of the fan interface and the ground according to a PWM signal when the fan interface is connected with a three-wire fan, so as to adjust the average input voltage of the three-wire fan, thereby adjusting the rotating speed of the three-wire fan. In this way, the utility model can adjust the rotating speed of the three-wire fan and the four-wire fan, the circuit structure is relatively simple, and the cost is relatively low. Even if the cooling system replaces the fan or is upgraded, the drive circuit does not need to be redesigned, and the compatibility and flexibility of the drive circuit are enhanced. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings described below only show some of the embodiments of the present application, and for those skilled in the art, other drawings can also be obtained according to the structures shown in these drawings without creative labor.

[0024] Figure 1 The structural schematic diagram of the fan driving circuit provided by the present application is shown in the figure.

[0025] Figure 2 The structural schematic diagram of the fan driving circuit provided by the present application is shown in the figure.

[0026] Figure 3 The electronic circuit diagram of the fan driving circuit provided by the present application is shown in the figure.

[0027] Explanation of the reference signs:

[0028] Reference Name Reference Name 01 Power input circuit 02 / FAN1 Fan interface 03 PWM input circuit 04 PWM control circuit 05 / J1 Control interface Q1 First switch tube R1~R3 First resistor~third resistor FB1~FB2 First magnetic bead~second magnetic bead D1 First diode C1~C2 First capacitor~second capacitor

[0029] The realization, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. Specific implementation

[0030] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0031] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present application are only used to explain the relative positional relationship, movement condition, etc. between the components in a certain posture (as shown in the drawings), and if the certain posture changes, the directional indications will also change accordingly.

[0032] In addition, the description of "first", "second" and the like in the present application is only for the purpose of description and cannot be understood as indicating or implying the relative importance of the technical features or implying the number of the technical features indicated. Therefore, the features limited by "first" and "second" can be explicitly or implicitly included at least one of the features. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the realization of ordinary skilled in the art, when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, and is not within the protection scope required by the present application.

[0033] The existing fan driving circuit usually only supports one type of fan, and cannot be compatible with different types of fans. Due to the difference in control mode of three-wire fans and four-wire fans, the existing fan driving circuit needs to be specially designed according to the fan type, which makes it necessary to redesign the driving circuit when replacing the fan type or upgrading the heat dissipation system, thereby increasing the development cost and reducing the flexibility of the system.

[0034] The utility model provides a fan driving circuit.

[0035] Please refer to Figure 1 In an embodiment of the present application, the fan driving circuit comprises:

[0036] The first signal input end is used for inputting a PWM signal.

[0037] The power input circuit 01 is connected with the external power input end at the power input end, and the ground end of the power input circuit 01 is grounded. The power input circuit 01 is used for inputting an external power voltage.

[0038] The fan interface 02 has a power pin, a ground pin and a control pin. The power pin of the fan interface 02 is connected with the first power end of the power input circuit 01, and the ground pin of the fan interface 02 is connected with the second power end of the power input circuit 01. The fan interface 02 is used for connecting a three-wire fan or a four-wire fan.

[0039] The PWM input circuit 03 is connected with the first signal input end at the input end, and the output end of the PWM input circuit 03 is connected with the control pin of the fan interface 02. The power end of the PWM input circuit 03 is connected with the first power end of the power input circuit 01. The PWM input circuit 03 is used for outputting a corresponding PWM control signal according to the PWM signal when the fan interface 02 is connected with a four-wire fan.

[0040] The PWM control circuit 04 is connected with the first signal input end, the first end of the PWM control circuit 04 is connected with the ground pin of the fan interface 02, and the second end of the PWM control circuit 04 is grounded. The PWM control circuit 04 is used for controlling the conduction state between the ground pin of the fan interface 02 and the ground according to the PWM signal when the fan interface 02 is connected with the three-wire fan, so as to adjust the average input voltage of the three-wire fan.

[0041] It should be noted that the power input circuit 01 can include a filter circuit and an anti-interference circuit. Specifically, the input power can be filtered to remove noise, suppress high-frequency noise and peak interference on the power line, and the like by using capacitors, magnetic beads and the like, so as to provide clean and stable power supply.

[0042] In the heat dissipation system, the existing heat dissipation fan is usually a three-wire fan or a four-wire fan. The three-wire fan includes a power supply pin, a ground pin and a detection pin. The four-wire fan further includes a control pin, and the speed of the four-wire fan can be directly adjusted by inputting a PWM control signal. In the embodiment, the fan interface 02 can be connected with a three-wire fan or a four-wire fan. The power supply pin, the ground pin and the control pin of the fan interface 02 are correspondingly connected with the power supply pin, the ground pin and the control pin of the fan, and can be compatible with the three-wire fan and the four-wire fan.

[0043] In the embodiment, the PWM input circuit 03 is connected with the power input circuit 01, and can provide a stable power supply voltage so that the output remains in a stable state. The PWM input circuit 03 can specifically include a plurality of resistors to form a voltage dividing network, and can convert the PWM signal into a PWM control signal. The voltage level of the PWM control signal input into the four-wire fan meets the requirements of the control pin of the four-wire fan, so that the signal can be correctly transmitted, and damage caused by voltage mismatch is avoided.

[0044] It should be noted that the average input voltage of the three-wire fan refers to the average voltage effectively input into the three-wire fan. Specifically, when the PWM signal is at a high level, the ground pin of the fan interface 02 is connected with the ground. When the PWM signal is at a low level, the ground pin is disconnected with the ground. Since the ground pin is periodically connected to the ground and disconnected, the three-wire fan actually receives a pulse signal. That is, the average voltage of the pulse signal input into the three-wire fan can be adjusted according to the duty cycle of the PWM signal in the embodiment, and the speed of the fan is adjusted.

[0045] In the embodiment, the power input circuit 01 can input an external power supply voltage. The fan interface 02 can be connected with a three-wire fan or a four-wire fan. The PWM input circuit 03 can output a corresponding PWM control signal according to a PWM signal when the fan interface 02 is connected with the four-wire fan, so as to adjust the rotating speed of the four-wire fan. The PWM control circuit 04 can control the conduction state between the ground pin of the fan interface 02 and the ground according to the PWM signal when the fan interface 02 is connected with the three-wire fan, so as to adjust the actual power supply time of the three-wire fan, the size of the average input voltage, and the rotating speed of the three-wire fan. In this way, the embodiment can be compatible with the rotating speed adjustment of the three-wire fan and the four-wire fan, the circuit structure is relatively simple, and the cost is relatively low. Even if the heat dissipation system replaces the fan or is upgraded, the driving circuit does not need to be redesigned, and the compatibility and flexibility of the driving circuit are enhanced.

[0046] In the embodiment, the power input circuit 01 can input an external power supply voltage. The fan interface 02 can be connected with a three-wire fan or a four-wire fan. The PWM input circuit 03 can output a corresponding PWM control signal according to a PWM signal when the fan interface 02 is connected with the four-wire fan, so as to adjust the rotating speed of the four-wire fan. The PWM control circuit 04 can control the conduction state between the ground pin of the fan interface 02 and the ground according to the PWM signal when the fan interface 02 is connected with the three-wire fan, so as to adjust the actual power supply time of the three-wire fan, the size of the average input voltage, and the rotating speed of the three-wire fan. In this way, the embodiment can be compatible with the rotating speed adjustment of the three-wire fan and the four-wire fan, the circuit structure is relatively simple, and the cost is relatively low. Even if the heat dissipation system replaces the fan or is upgraded, the driving circuit does not need to be redesigned, and the compatibility and flexibility of the driving circuit are enhanced.

[0047] Please refer to Figure 2 In the embodiment of the utility model, fan drive circuit still includes control interface 05, control interface 05 has power supply pin, ground pin, detection pin and control pin, control interface 05's power supply pin is connected with external power input, control interface 05's ground pin is grounded, wherein, control interface 05 is first signal input end,

[0048] Fan interface 02 still has detection pin, fan interface 02's detection pin is connected with control interface 05's detection pin, and fan interface 02's detection pin is used to input detection signal, and detection signal is used to indicate the rotating speed information of fan.

[0049] In an implementation, the fan driving circuit is applied to a fan control assembly which further comprises a controller and a three-wire / four-wire fan. The control interface 05 is used for connecting the controller, and the power supply pin of the control interface 05 can input stable and clean power supply to the controller to maintain the normal operation of the controller. The controller can output PWM signals with different duty cycles to the fan driving circuit through the control pin of the control interface 05 to adjust the rotating speed of the three-wire / four-wire fan. The detection pin of the fan interface 02 is connected with the detection pin of the three-wire / four-wire fan, and then the fan can output a detection signal for indicating the rotating speed information of the fan, the controller can acquire the detection signal, analyze the rotating speed information of the fan, and perform feedback adjustment, that is, according to the detection signal, the duty cycle of the output PWM signal is adjusted to make the rotating speed of the fan meet the expected setting. Thus, the rotating speed of the three-wire / four-wire fan can be accurately adjusted. Moreover, the detection signal can be used to quickly identify the situation such as fan jamming, abnormal speed drop, etc., so as to control the fan to stop rotating.

[0050] It should be noted that in the heat dissipation system, the controller can be connected with the temperature detection circuit, and the ambient temperature can be detected through the temperature detection circuit, and the rotating speed of the fan can be adjusted according to the ambient temperature, for example, a PWM signal with a larger duty cycle is output when the temperature is high to control the rotating speed of the fan to increase and accelerate heat dissipation, and a PWM signal with a smaller duty cycle is output when the temperature is low to control the rotating speed of the fan to decrease or even stop rotating, thereby saving electric energy while dissipating heat. Thus, automatic heat dissipation control can be realized.

[0051] Please refer to Figure 3 In an embodiment of the utility model, PWM control circuit 04 includes first switch tube Q1, the controlled end of first switch tube Q1 is connected with first signal input end, the first end of first switch tube Q1 is connected with the ground pin of fan interface 02, and the second end of first switch tube Q1 is grounded.

[0052] In an implementation, the first switch tube Q1 is an NMOS tube, and the PWM control circuit 04 further comprises a first resistor R1, one end of the first resistor R1 is connected with the first signal input end, the other end of the first resistor R1 is connected with the gate of the NMOS tube, the drain of the NMOS tube is connected with the ground pin of the fan interface 02, and the source of the NMOS tube is grounded.

[0053] In the embodiment, when the PWM signal is high, the NMOS is turned on, and the ground pin of the fan interface 02 is connected with the ground; when the PWM signal is low, the NMOS is turned off, and the ground pin of the fan interface 02 is disconnected with the ground. In this way, the duty cycle of the PWM signal can be changed to control the on time of the MOS, thereby controlling the on time between the ground pin of the fan interface 02 and the ground, adjusting the average voltage input to the three-wire fan, and further adjusting the rotation speed of the fan. The first resistor R1 can be used to limit the current and protect the normal work of the NMOS.

[0054] Referring to Figure 3 In an embodiment of the utility model, the PWM input circuit 03 includes the second resistor R2 and the third resistor R3, one end of the second resistor R2 is connected with the first power supply end of the power input circuit 01, the other end of the second resistor R2 and one end of the third resistor R3 are connected with the first signal input end, and the other end of the third resistor R3 is connected with the control pin of the fan interface 02.

[0055] In the embodiment, the voltage level of the input PWM signal is adjusted by the voltage division network formed by the second resistor R2 and the third resistor R3, so that the voltage level of the PWM control signal transmitted to the control pin of the fan interface 02 is ensured to be within a proper range.

[0056] Referring to Figure 3 In an embodiment of the utility model, the power input circuit 01 includes the first magnetic bead FB1 and the second magnetic bead FB2, one end of the first magnetic bead FB1 is connected with the external power input end, and the other end of the first magnetic bead FB1 is connected with the power pin of the fan interface 02; one end of the second magnetic bead FB2 is connected with the power pin of the fan interface 02, and the other end of the second magnetic bead FB2 is grounded.

[0057] In an embodiment, the power input circuit 01 further includes the first capacitor C1 and the second capacitor C2; one end of the first capacitor C1 is connected with one end of the first magnetic bead FB1, and the other end of the first capacitor C1 is grounded; one end of the second capacitor C2 is connected with the other end of the first magnetic bead FB1, and the other end of the second capacitor C2 is grounded.

[0058] In the embodiment, the first magnetic bead FB1 and the second magnetic bead FB2 have high impedance to high-frequency signals, can absorb and suppress high-frequency noise and peak interference on the power line. The first capacitor C1 and the second capacitor C2 can filter out ripples and noise on the power line and smooth the power voltage. In this way, the stability of the power input is ensured.

[0059] Referring to Figure 3In an embodiment of the utility model, fan drive circuit still includes first diode D1, the positive pole of first diode D1 is connected with the ground pin of fan interface 02, the negative pole of first diode D1 is connected with the power supply pin of fan interface 02.

[0060] Need to explain, when PWM control circuit 04 disconnects the ground pin of fan interface 02 and the connection of ground, the inductance in fan motor can try to maintain current flow, generates reverse electromotive force.This reverse electromotive force easily leads to voltage spike, damages MOS tube or other circuit elements.In this embodiment, when MOS tube is cut off, diode can provide low impedance path, allows current to continue to flow, thereby eliminating the voltage spike brought by reverse electromotive force, protects the safe work of MOS tube and other circuit elements.

[0061] The utility model also proposes a fan control assembly, the fan control assembly includes controller, fan and fan drive circuit, the specific structure of the fan drive circuit refers to the above-mentioned embodiment, because the fan control assembly of the utility model adopts all technical schemes of the above-mentioned all embodiments, therefore at least has all beneficial effects brought by the technical scheme of the above-mentioned embodiment, here will not repeat one by one.

[0062] Among them, the controller is connected with the control interface 05 of fan drive circuit, and the controller is used for adjusting the duty cycle of the output PWM signal according to the detection signal.The fan is connected with the fan interface 02 of fan drive circuit.Among them, the fan can be three-wire fan or four-wire fan.In the utility model, the fan control assembly can be compatible with the speed regulation of three-wire / four-wire fan, and can realize the accurate regulation of the speed of three-wire / four-wire fan.

[0063] The above-mentioned only is the exemplary implementation of the utility model, and does not limit the patent range of the utility model, and the equivalent structure transformation made with the utility model specification and attached drawing contents, or direct / indirect application in other related technical fields all include in the patent protection range of the utility model.

Claims

1. A fan driving circuit, characterized in that: include: A first signal input terminal, used for inputting a PWM signal; a power input circuit, wherein the power input terminal of the power input circuit is connected to the external power input terminal, and the ground terminal of the power input circuit is grounded; the power input circuit is used to input the external power supply voltage; A fan interface, the fan interface having a power pin, a ground pin, and a control pin, the power pin of the fan interface being connected to the first power terminal of the power input circuit, and the ground pin of the fan interface being connected to the second power terminal of the power input circuit; the fan interface being used for connecting a three-wire fan or a four-wire fan; a PWM input circuit, wherein an input end of the PWM input circuit is connected to the first signal input end, an output end of the PWM input circuit is connected to a control pin of the fan interface, and a power end of the PWM input circuit is connected to a first power end of the power input circuit; the PWM input circuit is configured to output a corresponding PWM control signal according to the PWM signal when the fan interface is connected to a four-wire fan; A PWM control circuit, wherein a controlled end of the PWM control circuit is connected to the first signal input end, a first end of the PWM control circuit is connected to a ground pin of the fan interface, and a second end of the PWM control circuit is grounded; the PWM control circuit is configured to control the conduction state between the ground pin of the fan interface and the ground according to the PWM signal when the fan interface is connected to a three-wire fan, so as to adjust the average input voltage of the three-wire fan.

2. The fan driving circuit according to claim 1, wherein: The fan drive circuit further includes a control interface having a power pin, a ground pin, a detection pin, and a control pin; the power pin of the control interface is connected to an external power input terminal, and the ground pin of the control interface is grounded; wherein the control pin of the control interface is the first signal input terminal; The fan interface further has a detection pin, which is connected to the detection pin of the control interface. The detection pin of the fan interface is used to input a detection signal; the detection signal is used to indicate the rotation speed information of the fan.

3. The fan driving circuit according to claim 2, wherein: The PWM control circuit includes a first switch tube, a controlled end of the first switch tube is connected to the first signal input end, a first end of the first switch tube is connected to the ground pin of the fan interface, and a second end of the first switch tube is grounded.

4. The fan driving circuit according to claim 3, wherein: The first switching tube is an NMOS tube, and the PWM control circuit also includes a first resistor, one end of the first resistor is connected to the first signal input end, the other end of the first resistor is connected to the gate of the NMOS tube, the drain of the NMOS tube is connected to the ground pin of the fan interface, and the source of the NMOS tube is grounded.

5. The fan driving circuit according to claim 2, wherein: The PWM input circuit includes a second resistor and a third resistor, one end of the second resistor is connected to the first power supply end of the power input circuit, the other end of the second resistor and one end of the third resistor are connected to the first signal input end, and the other end of the third resistor is connected to the control pin of the fan interface.

6. The fan driving circuit according to claim 2, wherein: The power input circuit includes a first magnetic bead and a second magnetic bead, one end of the first magnetic bead is connected to the external power input end, and the other end of the first magnetic bead is connected to the power pin of the fan interface; one end of the second magnetic bead is connected to the power pin of the fan interface, and the other end of the second magnetic bead is grounded.

7. The fan driving circuit according to claim 2, wherein: The fan driving circuit further includes a first diode, wherein an anode of the first diode is connected to a ground pin of the fan interface, and a cathode of the first diode is connected to a power pin of the fan interface.

8. The fan driving circuit according to claim 6, wherein: The power input circuit also includes a first capacitor and a second capacitor; wherein, one end of the first capacitor is connected to one end of the first magnetic bead, and the other end of the first capacitor is grounded; one end of the second capacitor is connected to the other end of the first magnetic bead, and the other end of the second capacitor is grounded.

9. A fan control assembly, characterized in that: The fan drive circuit according to any one of claims 2 to 8, wherein the fan control component further comprises: a controller connected to a control interface of the fan drive circuit, and configured to adjust a duty cycle of an output PWM signal according to the detection signal; A fan is connected to the fan interface of the fan driving circuit.

10. The fan control assembly according to claim 9, wherein: The fan is a three-wire fan or a four-wire fan.

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