A driving signal generating circuit and a fan control circuit

Abstract

The utility model relates to electronic circuit technical field discloses a kind of drive signal generation circuit and fan control circuit, comprising: control module, voltage division module and isolation module, wherein, the output end of control module is connected with the first end input of voltage division module, control module is used to output control voltage;The second input end of voltage division module inputs first external power supply voltage, the output end of voltage division module is connected with the input end of isolation module, voltage division module is used to output initial drive voltage after control voltage and first external power supply voltage voltage division;The output end of isolation module is connected with the control end of fan, isolation module is used to control the drive voltage of output amplitude following control voltage change after current one-way flow in control circuit, drive voltage is used to adjust the speed of fan.The utility model structure is simple, overall circuit cost is low, and anti-interference is strong.

Description

Technical Field

[0001] This utility model relates to the field of electronic circuit technology, specifically to a drive signal generation circuit and a fan control circuit. Background Technology

[0002] In related technologies, the processing of voltage signals for variable speed drive (VSP) fans often relies on traditional dual transistor push-pull circuits or similar complex level conversion architectures. These solutions require the integration of multiple functional components, such as transistors, Zener diodes, and isolation resistors. This not only presents high complexity in circuit design but also poses significant challenges to manufacturing due to the cumbersome circuit board layout and soldering processes. Furthermore, it necessitates greater investment in component selection, procurement, and inventory management, resulting in relatively high overall technical and cost barriers.

[0003] Traditional solutions also have significant functional limitations. To achieve level-following control, multiple transistors must be used to build a transistor pair circuit. Furthermore, to ensure circuit stability and safety, additional protective components such as voltage regulators and isolation devices are required. This results in a complex overall circuit and high material and production costs. On the one hand, its protection mechanism is relatively weak, lacking integrated defense against reverse interference voltages, often requiring additional dedicated protection devices, which further exacerbates the circuit's complexity and cost pressure. On the other hand, the rigid nature of the circuit structure makes its adaptability severely insufficient. When facing the different VSP voltage requirements of different wind turbine models, significant adjustments to component parameters are needed, and even redesign of the circuit topology is required. This results in significant shortcomings in flexibility and versatility, making it difficult to efficiently meet the diverse application scenarios. Utility Model Content

[0004] This invention provides a drive signal generation circuit and a fan control circuit to solve the problem of complex structure in traditional fan drive circuits.

[0005] In a first aspect, this utility model provides a drive signal generation circuit, comprising: a control module, a voltage divider module, and an isolation module. The output terminal of the control module is connected to the first input terminal of the voltage divider module, and the control module is used to output a control voltage. The second input terminal of the voltage divider module receives a first external power supply voltage, and the output terminal of the voltage divider module is connected to the input terminal of the isolation module. The voltage divider module is used to divide the control voltage and the first external power supply voltage and output an initial drive voltage. The output terminal of the isolation module is connected to the control terminal of the fan, and the isolation module is used to control the unidirectional flow of current in the circuit and output a drive voltage whose amplitude follows the change of the control voltage. The drive voltage is used to adjust the speed of the fan.

[0006] The drive signal generation circuit provided by this invention can stably generate an initial drive voltage that matches the fan speed control requirements by coordinating the control voltage output by the control module and the voltage divider module with the first external power supply voltage. Then, an isolation module enables unidirectional current flow control in the circuit, ultimately outputting a drive voltage whose amplitude changes synchronously with the control voltage to regulate the fan speed. This drive signal generation circuit not only accurately matches the voltage requirements of the fan for different speed controls, ensuring the stability and reliability of fan speed regulation, but also effectively blocks potential reverse interference voltage surges from the fan control terminal to the control module or voltage divider module by utilizing the unidirectional flow characteristic of the isolation module. This prevents damage to core circuit components due to reverse interference, significantly improving the overall circuit's anti-interference capability and operational safety. Simultaneously, the simplified functional coordination logic reduces circuit implementation complexity, helping to control production and application costs.

[0007] In one optional embodiment, the voltage divider module includes a first resistor and a second resistor, wherein a first end of the first resistor is connected to the output terminal of the control module, and a second end of the first resistor is connected to the first end of the second resistor and the input terminal of the isolation module; a first external power supply voltage is input to the second end of the second resistor.

[0008] In one alternative implementation, the isolation module includes a diode, wherein the anode of the diode is connected to the output terminal of the voltage divider module, and the cathode of the diode is connected to the control terminal of the fan.

[0009] In one optional implementation, the drive signal generation circuit further includes a filtering module, wherein a first terminal of the filtering module is connected to the output terminal of the isolation module, a second terminal of the filtering module is grounded, and the filtering module is used to filter out interference in the drive voltage.

[0010] In one optional implementation, the filtering module includes a capacitor, an electrolytic capacitor, and a third resistor, wherein the first end of the capacitor, electrolytic capacitor, and third resistor connected in parallel is connected to the output terminal of the isolation module, and the second end of the parallel connection is grounded.

[0011] In one optional embodiment, the drive signal generation circuit further includes a voltage regulator module, wherein a first terminal of the voltage regulator module receives a first external power supply voltage, a second terminal of the voltage regulator module is connected to the output terminal of the control module, and the voltage regulator module is used to limit the voltage at the output terminal of the control module.

[0012] Secondly, this utility model provides a fan control circuit, including: a speed feedback module and a drive signal generation circuit of the first aspect or any corresponding embodiment, wherein the input end of the speed feedback module is connected to the speed detection end of the fan, and the output end of the speed feedback module is connected to the input end of the control module in the drive signal generation circuit. The speed feedback module is used to convert the speed signal output by the fan into a pulse signal of a corresponding frequency and then send it to the control module.

[0013] The fan control circuit provided by this utility model achieves precise adjustment of the fan speed by using a drive signal generation circuit to stably output a drive voltage whose amplitude changes with the control module signal. Simultaneously, a speed feedback module converts the actual fan speed signal into a pulse signal of corresponding frequency and sends it back to the control module. This allows the control module to obtain the fan's operating status in real time, facilitating subsequent speed adjustment based on the real-time fan speed. Furthermore, the speed feedback module's conversion and processing of the speed signal ensures a clear and stable signal fed back to the control module, reducing the impact of signal interference on the control logic and further guaranteeing the reliability of the circuit operation. At the same time, the overall functional coordination logic balances speed adjustment accuracy and operational stability, meeting the efficient and stable control requirements of the fan in different scenarios.

[0014] In one optional implementation, the speed feedback module includes a switching unit and a current limiting unit, wherein the control terminal of the switching unit is connected to the speed detection terminal of the fan, the output terminal of the switching unit is connected to the first terminal of the current limiting unit, and the switching unit is used to output a pulse signal after switching the switching state based on the speed signal; the second terminal of the current limiting unit is connected to the input terminal of the control module, and the current limiting unit is used to limit the current magnitude of the pulse signal.

[0015] In one optional embodiment, the switching unit includes: a fourth resistor, a fifth resistor, and a controllable switch, wherein the first end of the fourth resistor is connected to the speed detection end of the fan, and the second end of the fourth resistor is connected to the control end of the controllable switch; the first end of the controllable switch is connected to the first end of the fifth resistor and the first end of the current limiting unit, and the second end of the controllable switch is grounded; the second end of the fifth resistor receives a second external power supply voltage.

[0016] In one alternative implementation, the current limiting unit includes a sixth resistor, wherein a first end of the sixth resistor is connected to the output terminal of the switching unit, and a second end of the sixth resistor is connected to the input terminal of the control module. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a composition diagram of the drive signal generation circuit according to an embodiment of the present utility model; Figure 2 This is a detailed circuit diagram of the drive signal generation circuit according to an embodiment of the present utility model; Figure 3 This is a composition diagram of the fan control circuit according to an embodiment of the present utility model; Figure 4 This is a detailed circuit diagram of the fan control circuit according to an embodiment of the present utility model. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0020] It is understood that before using the technical solutions disclosed in the various embodiments of this utility model, users should be informed of the types, scope of use, and usage scenarios of the personal information involved in this utility model in an appropriate manner in accordance with relevant laws and regulations, and user authorization should be obtained.

[0021] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0022] This embodiment provides a drive signal generation circuit, such as Figure 1 As shown, it includes: control module 11, voltage divider module 12 and isolation module 13.

[0023] Figure 1 In this circuit, the output terminal of the control module 11 is connected to the first input terminal of the voltage divider module 12, and the control module 11 is used to output the control voltage.

[0024] Specifically, Figure 1 In this system, the control module 11 serves as the core control unit, and the magnitude of its output control voltage directly determines the basic logic of the fan speed regulation. This control voltage is transmitted to the first input terminal of the voltage divider module 12 to provide a reference control signal for the generation of the subsequent drive voltage.

[0025] It should be noted that the process of the control module outputting the control voltage to set the target speed of the wind turbine relies on mature wind turbine speed regulation software in the existing technology. That is, this embodiment only protects the specific structure of the drive signal generation circuit, and does not protect the control method inside the control module.

[0026] Figure 1 In the process, the second input terminal of the voltage divider module 12 receives the first external power supply voltage, and the output terminal of the voltage divider module 12 is connected to the input terminal of the isolation module 13. The voltage divider module 12 is used to divide the control voltage and the first external power supply voltage and output the initial drive voltage.

[0027] Specifically, Figure 1 In the process, the second input terminal of the voltage divider module 12 is connected to the first external power supply voltage. This external power supply provides the necessary voltage support for the generation of the drive voltage. Based on its own working characteristics, the voltage divider module 12 performs coordinated voltage division processing on the input control voltage and the first external power supply voltage. By reasonably allocating the ratio of the two voltages, it finally outputs the initial drive voltage that meets the initial drive requirements of the wind turbine, ensuring that the initial voltage can not only adapt to the control logic of the wind turbine, but also reserve a suitable amplitude space for subsequent voltage adjustment.

[0028] Figure 1 In the middle, the output terminal of the isolation module 13 is connected to the control terminal of the fan. The isolation module 13 is used to control the current in the circuit to flow in one direction and output a drive voltage whose amplitude follows the change of the control voltage. The drive voltage is used to adjust the speed of the fan.

[0029] Specifically, Figure 1 In this circuit, the isolation module 13 serves as a crucial protection element. Internally, it utilizes unidirectional conductive devices to allow current to flow unidirectionally from the voltage divider module 12 to the control terminal of the fan, thereby outputting the final drive voltage. Due to the unidirectional conduction characteristic of the isolation module 13, the amplitude of its output drive voltage will have a fixed voltage drop based on the initial drive voltage, but its variation pattern and trend completely follow the control voltage issued by the control module 11. Therefore, when the control voltage increases or decreases, the drive voltage also changes proportionally, thus precisely achieving linear regulation of the fan speed.

[0030] Specifically, Figure 1In this system, the isolation module 13, with its unidirectional conductivity, constructs an effective electrical barrier that completely prevents current or voltage signals from back-interfering from the wind turbine's control terminal to the upstream voltage divider module 12 and control module 11. This inherent unidirectional isolation mechanism effectively blocks induced electromotive force, voltage surges, or other electromagnetic interference that may be generated on the wind turbine's load side, thereby protecting sensitive control signal sources from damage and greatly improving the overall system's anti-interference capability and long-term operational reliability.

[0031] The drive signal generation circuit provided in this embodiment can stably generate an initial drive voltage that matches the fan speed control requirements by coordinating the control voltage output by the control module and the voltage divider module with the first external power supply voltage. Then, the isolation module enables unidirectional current flow control in the circuit, ultimately outputting a drive voltage whose amplitude changes synchronously with the control voltage to adjust the fan speed. This drive signal generation circuit not only accurately matches the voltage requirements of the fan for different speed controls, ensuring the stability and reliability of fan speed regulation, but also effectively blocks potential reverse interference voltage surges from the fan control terminal to the control module or voltage divider module by utilizing the unidirectional flow characteristic of the isolation module. This prevents damage to core circuit components due to reverse interference, significantly improving the overall circuit's anti-interference capability and operational safety. Simultaneously, the simplified functional coordination logic reduces circuit implementation complexity, helping to control production and application costs.

[0032] In some alternative implementations, such as Figure 2 As shown, the voltage divider module 12 includes a first resistor R1 and a second resistor R2. The first end of the first resistor R1 is connected to the output terminal of the control module 11, and the second end of the first resistor R1 is connected to the first end of the second resistor R2 and the input terminal of the isolation module 13. The second end of the second resistor R2 is input with a first external power supply voltage (i.e., +15V).

[0033] Specifically, Figure 2 In this circuit, the first external power supply voltage acts as a fixed pull-up source, influencing the network through the second resistor R2; while the variable control voltage output by the control module 11 is injected into the network through the first resistor R1. The two voltages are superimposed and divided at the common node of the first resistor R1 and the second resistor R2. (1) When the control voltage is high, the high level raises the potential of the first end of the first resistor R1, so that the initial drive voltage of the output node is the sum of the voltage division of the first external power supply voltage in the series circuit of R1 and R2 and the voltage division of the control voltage in the series circuit of R2 and R1.

[0034] (2) When the control voltage is low or zero, the voltage of the output node is basically equal to the simple voltage division of the first external power supply voltage across R1 and R2. Therefore, the amplitude of the initial drive voltage output by the voltage divider module 12 is determined by both the first external power supply voltage and the control voltage, and precisely follows the change of the control voltage.

[0035] Specifically, Figure 2 In this circuit, isolation module 13 includes a diode D1. The anode of diode D1 is connected to the output terminal of voltage divider module 12, and the cathode of diode D1 is connected to the control terminal (VSP-FAN terminal) of the fan (i.e., the DC-FAN module). Diode D1 utilizes its forward conduction characteristic to level-shift the initial drive voltage generated by voltage divider module 12. Due to the forward voltage drop of the diode, the final drive voltage output to the fan control terminal will be reduced by approximately 0.7V from the initial drive voltage. Additionally, diode D1 also serves as isolation protection; its unidirectional conductivity effectively prevents current from flowing backward from the fan control terminal into the upstream circuit. When the fan generates a reverse electromotive force due to electromagnetic interference or sudden load changes, diode D1 immediately enters a reverse cutoff state, forming an electrical isolation barrier to prevent abnormal high voltage or interference signals from impacting voltage divider module 12 and control module 11, thereby ensuring the stability and reliability of the entire control system. This design achieves necessary level conversion and provides an inherent protection mechanism for the circuit.

[0036] Figure 2 The drive signal generation circuit further includes a filter module 14, wherein the first terminal of the filter module 14 is connected to the output terminal of the isolation module 13, and the second terminal of the filter module 14 is grounded. The filter module 14 is used to filter out interference in the drive voltage. The filter module 14 is used to purify the final drive voltage that is about to be sent to the fan, filtering out high-frequency noise and interference that may be introduced during transmission, ensuring the purity and stability of the drive signal, thereby improving the accuracy of fan speed control and the smoothness of operation.

[0037] Specifically, Figure 2 In this circuit, the filter module 14 includes a capacitor C1, an electrolytic capacitor E1, and a third resistor R3. The first terminal of the parallel connection of capacitor C1, electrolytic capacitor E1, and third resistor R3 is connected to the output terminal of the isolation module 13, and the second terminal is grounded. Capacitor C1 primarily absorbs and bypasses high-frequency interference components in the drive voltage signal; electrolytic capacitor E1, with its large capacitance, focuses on filtering out low-frequency ripple and providing local transient current compensation; the third resistor R3 acts as a damper in this parallel circuit, effectively suppressing resonance peaks that may be caused by the capacitor and line inductance, further enhancing the stability of the filtering effect. This composite filter network, composed of components with different characteristics, collectively ensures that the drive voltage signal output to the fan control terminal has extremely high quality.

[0038] Figure 2 In the driving signal generation circuit, there is also a voltage regulator module 15, wherein the first terminal of the voltage regulator module 15 is input with a first external power supply voltage, the second terminal of the voltage regulator module 15 is connected to the output terminal of the control module 11, and the voltage regulator module 15 is used to limit the voltage of the output terminal of the control module 11.

[0039] Specifically, Figure 2 In this circuit, the voltage regulator module 15 includes a diode D2. When the voltage at the output terminal of the control module 11 suddenly rises due to external interference or circuit abnormality, and the voltage at the output terminal of the control module 11 exceeds the sum of the first external power supply voltage and the forward voltage drop of diode D2, diode D2 immediately conducts forward, forming a current discharge path from the output terminal of the control module 11 to the first external power supply. This effectively clamps the highest voltage at the output terminal of the control module 11 to the level of the first external power supply voltage plus the forward voltage drop of the diode, providing reliable overvoltage protection for the control module 11.

[0040] For example, refer to Figure 2 The first resistor R1 is 10KΩ and the second resistor R2 is 1KΩ.

[0041] When the control voltage output by control module 11 is high, such as 5V, the voltage V0 at the voltage divider point of R1 and R2 is calculated using the following formula: V0=(15V 5V)×[R2 / (R1+R2)]+5V=10V×[1K / (1K+10K)]+5V=5.9V (1) The voltage at the voltage divider point, after passing through the approximately 0.7V forward voltage drop of diode D1, yields the driving voltage VSP as follows: VSP=V0 0.7V = 5.9V 0.7V = 5.2V (2) When the control voltage output by control module 11 is low, such as 0V, the voltage V0 at the voltage divider point of R1 and R2 is calculated using the following formula: V0=15V×[R2 / (R1+R2)]=15V×[1K / (1K+10K)]=1.36V (3) The voltage at the voltage divider point, after passing through the approximately 0.7V forward voltage drop of diode D1, yields the driving voltage VSP as follows: VSP=V0 0.7V = 1.36V 0.7V = 0.66V (4) In other words, this embodiment utilizes a very simple circuit structure to achieve effective tracking of the driving voltage VSP and the control voltage. Simultaneously, diode D1 plays a dual role in the circuit: it is both a key component for voltage conversion and a protective device to prevent backflow of interference from the output to the input, thus eliminating the need for additional protection circuitry and achieving a unified function and protection.

[0042] This embodiment provides a fan control circuit, such as Figure 3 As shown, it includes: a speed feedback module 2 and a drive signal generation circuit 1 of the first aspect or any corresponding embodiment described above, wherein the input end of the speed feedback module 2 is connected to the speed detection end of the fan, and the output end of the speed feedback module 2 is connected to the input end of the control module 11 in the drive signal generation circuit 1. The speed feedback module 2 is used to convert the speed signal output by the fan into a pulse signal of a corresponding frequency and then send it to the control module 11.

[0043] Specifically, Figure 3 In the middle, the speed feedback module 2 is used to realize the conversion and transmission of signal form. By continuously monitoring the original electrical signal output by the fan speed detection terminal, it converts it into a pulse signal with a clear frequency characteristic through the internal circuit and inputs it to the control module 11. The frequency of these pulse signals maintains a strict correspondence with the actual speed of the fan, thereby accurately reflecting the operating status of the fan. This allows the control module 11 to adjust the output control voltage based on the real-time speed of the fan using existing mature feedback control software in a closed loop, thereby stabilizing the fan speed within the normal operating speed range.

[0044] The wind turbine control circuit provided in this embodiment achieves precise adjustment of the wind turbine speed by using a drive signal generation circuit to stably output a drive voltage whose amplitude changes with the control module signal. Simultaneously, a speed feedback module converts the actual wind turbine speed signal into a pulse signal of corresponding frequency and sends it back to the control module. This allows the control module to obtain the wind turbine's operating status in real time, facilitating subsequent speed adjustment based on the real-time wind turbine speed. Furthermore, the speed feedback module's conversion and processing of the speed signal ensures a clear and stable signal fed back to the control module, reducing the impact of signal interference on the control logic and further guaranteeing the reliability of the circuit operation. At the same time, the overall functional coordination logic balances speed adjustment accuracy and operational stability, meeting the high-efficiency and stable control requirements of the wind turbine in different scenarios.

[0045] In some optional implementations, the speed feedback module 2 includes a switching unit 21 and a current limiting unit 22. The control terminal of the switching unit 21 is connected to the speed detection terminal (i.e., the FG-FAN terminal) of the fan, and the output terminal of the switching unit 21 is connected to the first terminal of the current limiting unit 22. The switching unit 21 is used to switch the switching state based on the speed signal and then output a pulse signal. The second terminal of the current limiting unit 22 is connected to the input terminal of the control module 11, and the current limiting unit 22 is used to limit the current magnitude of the pulse signal.

[0046] Specifically, Figure 4 In the switch unit 21, there are: a fourth resistor R4, a fifth resistor R5 and a controllable switch Q1. The first end of the fourth resistor R4 is connected to the speed detection terminal of the fan, and the second end of the fourth resistor R4 is connected to the control terminal of the controllable switch Q1. The first end of the controllable switch Q1 is connected to the first end of the fifth resistor R5 and the first end of the current limiting unit 22, and the second end of the controllable switch Q1 is grounded. The second end of the fifth resistor R5 receives the second external power supply voltage.

[0047] Specifically, Figure 4 In the current limiting unit 22, there is a sixth resistor R6, wherein the first end of the sixth resistor R6 is connected to the output end of the switching unit 21, and the second end of the sixth resistor R6 is connected to the input end of the control module 11.

[0048] Specifically, Figure 4 In the fan, the built-in speed measurement circuit outputs a speed signal as the fan blades rotate. For example, the fan outputs a fixed number of pulses per revolution, such as 12 pulses per revolution. The high and low level changes of these pulses cause the controllable switch Q1 to switch between on and off states. When the speed signal is high, the second external power supply voltage provides a bias voltage to the control terminal of the controllable switch Q1 through the fifth resistor R5, causing it to conduct. At this time, the output node is pulled to a low level. When the speed signal is low, the pull-down current generated by the low level reduces the voltage at the control terminal of the controllable switch Q1 through the fourth resistor R4, causing Q1 to turn off. At this time, the output node is pulled to a high level through the fifth resistor R5.

[0049] After this cycle, each pulse of the fan speed signal corresponds to a switching of the controllable switch Q1 between on and off states, thereby generating a digital pulse sequence at the output that is strictly synchronized with the speed, thus realizing a reliable conversion from the speed signal to the standard pulse signal.

[0050] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A driving signal generation circuit, characterized in that, include: The control module, voltage divider module, and isolation module are included. The output terminal of the control module is connected to the first input terminal of the voltage divider module, and the control module is used to output control voltage; The second input terminal of the voltage divider module receives the first external power supply voltage, and the output terminal of the voltage divider module is connected to the input terminal of the isolation module. The voltage divider module is used to divide the control voltage and the first external power supply voltage and output the initial drive voltage. The output terminal of the isolation module is connected to the control terminal of the fan. The isolation module is used to control the current in the circuit to flow in one direction and output a driving voltage whose amplitude follows the change of the control voltage. The driving voltage is used to adjust the speed of the fan.

2. The drive signal generation circuit according to claim 1, characterized in that, The voltage divider module includes: a first resistor and a second resistor, wherein... The first end of the first resistor is connected to the output terminal of the control module, and the second end of the first resistor is connected to the first end of the second resistor and the input terminal of the isolation module. The second terminal of the second resistor is input with the first external power supply voltage.

3. The drive signal generation circuit according to claim 1, characterized in that, The isolation module includes: a diode, wherein, The anode of the diode is connected to the output terminal of the voltage divider module, and the cathode of the diode is connected to the control terminal of the fan.

4. The drive signal generation circuit according to claim 1, characterized in that, Also includes: The filtering module, in which, The first end of the filtering module is connected to the output end of the isolation module, and the second end of the filtering module is grounded. The filtering module is used to filter out interference in the driving voltage.

5. The drive signal generation circuit according to claim 4, characterized in that, The filtering module includes: a capacitor, an electrolytic capacitor, and a third resistor, wherein, The first end of the parallel connection of the capacitor, the electrolytic capacitor, and the third resistor is connected to the output end of the isolation module, and the second end of the parallel connection is grounded.

6. The drive signal generation circuit according to claim 1, characterized in that, Also includes: Voltage regulator module, among which, The first terminal of the voltage regulator module receives a first external power supply voltage, and the second terminal of the voltage regulator module is connected to the output terminal of the control module. The voltage regulator module is used to limit the voltage at the output terminal of the control module.

7. A fan control circuit, characterized in that, include: The speed feedback module and the drive signal generation circuit according to any one of claims 1 to 6, wherein, The input terminal of the speed feedback module is connected to the speed detection terminal of the fan, and the output terminal of the speed feedback module is connected to the input terminal of the control module in the drive signal generation circuit. The speed feedback module is used to convert the speed signal output by the fan into a pulse signal of corresponding frequency and then send it to the control module.

8. The fan control circuit according to claim 7, characterized in that, The speed feedback module includes: a switching unit and a current limiting unit, wherein... The control terminal of the switching unit is connected to the speed detection terminal of the fan, and the output terminal of the switching unit is connected to the first terminal of the current limiting unit. The switching unit is used to switch the switching state based on the speed signal and then output a pulse signal. The second end of the current limiting unit is connected to the input end of the control module, and the current limiting unit is used to limit the current magnitude of the pulse signal.

9. The fan control circuit according to claim 8, characterized in that, The switching unit includes: a fourth resistor, a fifth resistor, and a controllable switch, wherein... The first end of the fourth resistor is connected to the speed detection end of the fan, and the second end of the fourth resistor is connected to the control end of the controllable switch. The first terminal of the controllable switch is connected to the first terminal of the fifth resistor and the first terminal of the current limiting unit, and the second terminal of the controllable switch is grounded. The second terminal of the fifth resistor receives the second external power supply voltage.

10. The fan control circuit according to claim 8, characterized in that, The current limiting unit includes: a sixth resistor, wherein, The first end of the sixth resistor is connected to the output end of the switching unit, and the second end of the sixth resistor is connected to the input end of the control module.

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