Fan speed regulation circuit, control system and fan

Abstract

The utility model discloses a fan speed regulation circuit, a control system and a fan, the fan speed regulation circuit comprises an isolation control module, a power conversion module and a voltage clamping module, the isolation control module electrically isolates a first control signal and then outputs a second control signal; the power conversion module outputs a third control signal according to the second control signal, the voltage clamping module adjusts the power conversion module to output a starting signal after receiving the second control signal in the power-on process so as to control the fan to start to operate, and the voltage clamping module adjusts the power conversion module to output a starting signal after receiving the second control signal in the power-off process so as to control the fan to start to operate. The power conversion module is adjusted to output a stop signal before stopping receiving the second control signal so as to control the fan to stop running; according to the technical scheme, the problem of fan misoperation caused by delay or failure of establishment of the control signal can be effectively avoided, and in the power-on or power-off process, it can be ensured that the fan operates only under the conditions that the control signal is effective and power supply is stable, so that the safety and reliability of system operation are improved.

Description

Technical Field

[0001] This utility model relates to the field of electronic circuit technology, and in particular to a fan speed control circuit, a control system, and a fan. Background Technology

[0002] In electronic systems requiring heat dissipation, such as frequency converters and power modules, fans are one of the most common heat dissipation methods. Adjusting fan speed not only achieves effective heat dissipation but also improves overall system energy efficiency and reduces noise and energy consumption. Traditional fan speed control circuits often use PWM (Pulse Width Modulation) signals to control the fan's start, stop, and speed. However, in practical applications, using PWM signals for fan start, stop, and speed control can lead to situations where the control signal has not yet been established or has failed, while the fan power supply is still available. This can result in abnormal fan operation, uncontrolled rotation, or even malfunction. For example, during system power-on or power-off, if the control signal has failed but the power supply voltage has not completely disappeared, the fan may continue to run uncontrolled, posing a safety hazard. Utility Model Content

[0003] This utility model provides a fan speed control circuit, a control system, and a fan to solve the above-mentioned technical problems.

[0004] The first aspect of this utility model provides a fan speed control circuit, including:

[0005] An isolation control module is connected to the power supply voltage and the first control signal respectively. After electrically isolating the first control signal, it outputs the second control signal.

[0006] A power conversion module, which is connected to the output terminal of the isolation control module, is used to output a third control signal according to the second control signal, the third control signal including a start signal and a stop signal;

[0007] A voltage clamping module, which is connected to the power conversion module and the power supply voltage respectively, is used to adjust the power conversion module to output the start signal after receiving the second control signal during the power-on process, so as to control the fan to start running, and to adjust the power conversion module to output the stop signal before stopping receiving the second control signal during the power-off process, so as to control the fan to stop running.

[0008] Optionally, the isolation control module includes an input port and an output port. The input terminal of the input port receives a first voltage, the output terminal of the input port receives the first control signal, the input terminal of the output port receives the power supply voltage, and the output terminal of the output port is connected to the output terminal of the power conversion module.

[0009] In the power-on process, the isolation control module outputs a second control signal when the voltage value of the first control signal rises to a first preset voltage value;

[0010] In the power-off process, the isolation control module stops outputting the second control signal when the voltage value of the first control signal decreases to less than the first preset voltage value.

[0011] Optionally, the isolation control module comprises a first biasing module, a first switching module and an optical coupling module, the optical coupling module comprises a light-emitting diode and a photo triode, the anode of the light-emitting diode is the input end of the input port, the cathode of the light-emitting diode is connected to the input end of the first switching module, the control end of the first switching module and the first end of the first biasing module are commonly connected as the output end of the input port, the output end of the first switching module and the first end of the first biasing module are commonly connected to the ground, the collector of the photo triode is the input end of the output port, and the emitter of the photo triode is the output end of the output port.

[0012] Optionally, the first end of the voltage clamping module is connected to the power supply voltage, the second end of the voltage clamping module and the first end of the power conversion module are commonly connected as the output end of the isolation control module, the third end of the voltage clamping module and the second end of the power conversion module are commonly connected to the ground, and the control end of the power conversion module is connected to the output end of the isolation control module.

[0013] In the power-on process, after the voltage value of the first control signal rises to the first preset voltage value, the voltage clamping module outputs the start signal after performing pull-up clamping on the third control signal.

[0014] In the power-off process, before the voltage value of the first control signal decreases to less than the first preset voltage value, the voltage clamping module outputs the stop signal after performing pull-down clamping on the third control signal.

[0015] Optionally, the voltage clamping module comprises a first voltage clamping module and a second voltage clamping module, the first end of the first voltage clamping module and the first end of the second voltage clamping module are commonly connected as the first end of the voltage clamping module, the second end of the first voltage clamping module and the second end of the second voltage clamping module are commonly connected as the second end of the voltage clamping module, and the third end of the first voltage clamping module and the third end of the second voltage clamping module are commonly connected as the third end of the voltage clamping module.

[0016] In the power-on process, after the voltage value of the first control signal rises to the first preset voltage value, the first voltage clamping module outputs the start signal after performing pull-up clamping on the third control signal.

[0017] In the power-down process, the second voltage clamping module outputs the stop signal after pulling down and clamping the third control signal when the voltage value of the first control signal is reduced to less than a first preset voltage value.

[0018] Optionally, the first voltage clamping module comprises a first current limiting module, a first voltage stabilizing module and a second voltage stabilizing module, a first end of the first current limiting module is a first end of the first voltage clamping module, a second end of the first current limiting module is connected to an input end of the first voltage stabilizing module, an output end of the first voltage stabilizing module and an input end of the second voltage stabilizing module are commonly connected as a second end of the first voltage clamping module, and an output end of the second voltage stabilizing module is a third end of the first voltage clamping module.

[0019] Optionally, the second voltage clamping module comprises a first voltage dividing module, a second voltage dividing module, a third switch module, a second current limiting module and a fourth switch module, a first end of the first voltage dividing module and a first end of the second current limiting module are commonly connected as a first end of the second voltage clamping module, a second end of the first voltage dividing module is connected to a first end of the second voltage dividing module and a control end of the third switch module respectively, a second end of the second current limiting module is connected to a first end of the third switch module and a control end of the fourth switch module respectively, a first end of the fourth switch module is a second end of the second voltage clamping module, and a second end of the second voltage dividing module, a second end of the third switch module and a second end of the fourth switch module are commonly connected as a third end of the second voltage clamping module.

[0020] Optionally, the power conversion module comprises a second biasing module and a second switch module, a first end of the second biasing module and a control end of the second switch module are commonly connected as a control end of the power conversion module, a first end of the second switch module is a first end of the power conversion module, and a second end of the second biasing module and a second end of the second switch module are commonly connected as a second end of the power conversion module.

[0021] The utility model embodiment second aspect provides a fan control system, the fan control system includes the fan speed regulation circuit and control chip of first aspect, the control chip outputs first control signal to the isolation control module.

[0022] The utility model embodiment third aspect provides a fan, the fan includes the fan control system and executing mechanism of second aspect, and the executing mechanism receives the third control signal that the power conversion module outputs.

[0023] The technical effect of the embodiment of the utility model is: through setting isolation control module, power conversion module and voltage clamping module, the control management and abnormal state protection of fan start-stop are realized; compared with traditional PWM speed regulation circuit, the technical scheme can effectively avoid the fan misoperation problem caused by control signal establishment delay or failure, especially during power-on or power-off process, can ensure that the fan only runs under the condition that the control signal is effective and the power supply is stable, thereby improving the safety and reliability of system operation. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical scheme of the embodiment of the utility model, the drawings needed to be used in the description of the embodiment of the utility model will be briefly introduced, and obviously, the drawings in the following description are only some embodiments of the utility model, and other drawings can be obtained according to these drawings without creative labor for those skilled in the art.

[0025] Figure 1 It is a structural schematic diagram of a fan speed regulation circuit provided by the embodiment one of the utility model;

[0026] Figure 2 It is an interface schematic diagram of an isolation control module in a fan speed regulation circuit provided by the embodiment one of the utility model;

[0027] Figure 3 It is a structural schematic diagram of an isolation control module in a fan speed regulation circuit provided by the embodiment one of the utility model;

[0028] Figure 4 It is a structural schematic diagram of a power conversion module in a fan speed regulation circuit provided by the embodiment one of the utility model;

[0029] Figure 5 It is a connection schematic diagram of a power conversion module and a voltage clamping module in a fan speed regulation circuit provided by the embodiment one of the utility model;

[0030] Figure 6 It is a structural schematic diagram of a first voltage clamping module of a fan speed regulation circuit provided by the embodiment one of the utility model;

[0031] Figure 7 It is a structural schematic diagram of a second voltage clamping module of a fan speed regulation circuit provided by the embodiment one of the utility model;

[0032] Figure 8 It is a circuit diagram of a fan speed regulation circuit provided by the embodiment one of the utility model;

[0033] Figure 9The utility model embodiment one provides a fan speed regulation circuit upper electric process first control signal and voltage variation schematic diagram of power voltage.

[0034] Figure 10 The utility model embodiment one provides a fan speed regulation circuit lower electric process first control signal and voltage variation schematic diagram of power voltage.

[0035] Figure 11 The utility model embodiment two provides a fan control system's structure schematic diagram.

[0036] Figure 12 The utility model embodiment three provides a fan's structure schematic diagram.

[0037] In the drawing: 101, isolation control module;102, power conversion module;103, voltage clamping module;111, first bias module;112, first switch module;113, photocoupler module;121, second bias module;122, second switch module;131, first clamping module;132, second clamping module;141, first current limiting module;142, first voltage stabilizing module;143, second voltage stabilizing module;151, first voltage dividing module;152, second voltage dividing module;153, second current limiting module;154, third switch module;155, fourth switch module;200, control chip;300, actuating mechanism. DETAILED DESCRIPTION

[0038] The technical scheme in the utility model embodiments will be described clearly and completely below in conjunction with the drawings in the utility model embodiments, obviously, the described embodiments are a part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by the person skilled in the art without making creative efforts belong to the range of protection of the utility model.

[0039] It should be understood that the utility model can be implemented in different forms, and should not be interpreted as being limited to the embodiments presented here. On the contrary, the presentation of these embodiments will make the disclosure complete and complete, and will fully convey the scope of the utility model to the person skilled in the art. In the drawings, in order to be clear, the size and relative size of layers and regions may be exaggerated throughout the same reference signs represent the same elements.

[0040] It will be understood that when an element or layer is referred to as being "on", "adjacent", "connected to" or "coupled to" another element or layer, it can be directly on, adjacent, connected or coupled to the other element or layer, or intervening elements or layers can be present. In contrast, when an element is referred to as being "directly on", "directly adjacent", "directly connected to", or "directly coupled to" another element or layer, there are no intervening elements or layers present. It will be understood that, although the terms first, second, third, etc. can be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present application.

[0041] For a thorough understanding of the present application, reference will be made to the following detailed description, in conjunction with the accompanying drawings, in which:

[0042] Embodiment One

[0043] The embodiment one provides a fan speed regulation circuit, as shown in the figure, comprising: Figure 1

[0044] The isolation control module 101 is connected with the power voltage U0 and the first control signal K1 respectively, and outputs the second control signal K2 after electrically isolating the first control signal K1.

[0045] The power conversion module 102 is connected with the output end of the isolation control module 101, and is used for outputting the third control signal K3 according to the second control signal K2, wherein the third control signal K3 comprises a start signal and a stop signal.

[0046] The voltage clamping module 103 is connected with the power conversion module 102 and the power voltage U0 respectively, and is used for adjusting the power conversion module 102 to output the start signal after receiving the second control signal K2 in the power-on process, so as to control the fan to start running, and adjusting the power conversion module 102 to output the stop signal before stopping receiving the second control signal K2 in the power-off process, so as to control the fan to stop running.

[0047] ​The isolation control module 101 is configured to receive the first control signal K1 from the control chip or the master control unit, and perform electrical isolation processing on the first control signal K1 to output a second control signal K2 for driving a subsequent circuit. The isolation control module 101 includes but is not limited to the following structure: an optical coupling isolation circuit, which turns on a light-sensitive transistor through an LED to realize signal isolation transmission; a digital isolator, such as a digital isolation chip, which has faster response and longer service life. The power conversion module 102 is configured to receive the second control signal K2 after isolation, and output a third control signal K3 according to the state thereof, which includes a fan start signal and a fan stop signal, and is used for directly controlling the working state of the fan or generating a PWM speed regulation signal; the power conversion module 102 includes but is not limited to the following structure: a power MOSFET or IGBT driving circuit, which receives the isolated control signal to control the conduction / cutoff of a power switching device; a PWM speed regulation circuit, which controls the fan speed by changing the duty cycle of the PWM; a driving IC, which integrates driving logic and overcurrent protection functions. The voltage clamping module 103 is configured to delay the start action of the power conversion module 102 when the power supply voltage U0 is established or drops, to ensure that the fan start signal is output after the second control signal K2 is valid; and to pull down the PWM signal in advance when the power supply voltage U0 drops, to ensure that the fan stops running before the control signal is invalid, thereby avoiding fan operation under abnormal voltage or control state. The voltage clamping module 103 includes but is not limited to the following structure: an RC delay circuit, which uses a resistor-capacitor combination to form a charging and discharging time delay, so that a delay response is generated when the third control signal K3 is generated during the process in which the second control signal K2 reaches the power conversion module 102, thereby preventing the fan from starting immediately when the power supply is unstable; a Zener diode and a transient voltage suppressor (TVS): used for clamping the input voltage to prevent the power module from malfunctioning under a surge voltage or incomplete power-off; a comparator reference voltage circuit: used for detecting whether the power supply voltage U0 is stable or high enough to allow the start signal to be transmitted; and used for maintaining the stop signal for a period of time when the voltage drops but does not completely disappear.

[0048] The working process of the embodiment is as follows:

[0049] S1. Power-on stage: the power supply voltage U0 is connected, power supply starts, the isolation control module 101 receives the first control signal K1 from the external controller (such as the on / off instruction from the MCU or the temperature control module); the isolation control module 101 completes electrical isolation through an optical coupler or a digital isolation chip, and converts the first control signal K1 into the second control signal K2 after isolation. The voltage clamping module 103 only makes the power conversion module 102 output the third control signal K3 after the voltage reaches a certain threshold value (through RC delay, comparator judgment, etc.), so as to avoid abnormal start of the fan due to voltage fluctuation when the power is just turned on; once the condition is met, the start signal in the third control signal K3 output by the power conversion module 102 drives the actuator to turn on, and the fan motor starts to run, entering the normal running state.

[0050] S2. Normal running stage: the power conversion module 102 continuously outputs the control signal according to the characteristics of the second control signal K2, which may be a constant level or a PWM signal, to realize different speed control of the fan, and the fan keeps running until a stop signal is received.

[0051] S3. Power-off stage: when the system is powered off or the external controller issues a shutdown instruction, the first control signal K1 gradually decreases; the isolation control module 101 correspondingly gradually stops outputting the second control signal K2; the voltage clamping module 103 adjusts the power conversion module 102 to output a stop signal before stopping receiving the second control signal, and the fan is powered off and stopped.

[0052] The technical effect of the technical solution provided by the embodiment one is that by setting the isolation control module 101, the power conversion module 102 and the voltage clamping module 103, the control and management of fan start and stop and the abnormal state protection are realized; compared with the traditional PWM speed regulation circuit, the technical solution can effectively avoid the fan misoperation problem caused by the delay or failure of the control signal, especially during power-on or power-off, and can ensure that the fan runs only when the control signal is valid and the power supply is stable, thereby improving the safety, reliability and energy efficiency of system operation.

[0053] As an embodiment of the isolation control module 101, as shown in Figure 2 the isolation control module 101 includes an input port and an output port, the input end of the input port receives the first voltage U1, the output end of the input port receives the first control signal K1, the input end of the output port receives the power supply voltage U0, and the output end of the output port is connected to the output end of the power conversion module 102;

[0054] During power-on, the isolation control module 101 outputs the second control signal K2 when the voltage value of the first control signal K1 rises to a first preset voltage value;

[0055] In the power-off process, the isolation control module 101 stops outputting the second control signal K2 when the voltage value of the first control signal K1 decreases to less than the first preset voltage value.

[0056] The isolation control module 101 is used to realize electrical isolation between the control signal and the power output, and includes an input port and an output port: the input end of the input port receives a first voltage U1, which is preferably the working voltage on the control chip side; the output end of the input port receives a first control signal K1, which is usually a PWM signal or a high-low level signal output by the control chip, used to control the start-stop or speed regulation of the fan; the input end of the output port receives a power supply voltage U0, for example, a 24V power supply voltage; and the output end of the output port is connected to the control port of the power conversion module 102, used to output a second control signal K2. The isolation control module 101 includes but is not limited to an optoelectronic coupler to realize electrical isolation, and the input side can be a light-emitting diode receiving the first control signal, and the output side is a light-dependent triode outputting the second control signal K2. In the system power-on process, as the voltage of the first control signal K1 gradually increases, when it reaches the set first preset voltage value, the input side of the isolation control module 101 is turned on, the output end starts to output the effective second control signal K2, and the voltage clamping module 103 adjusts to drive the power conversion module 102 to output a start signal after receiving the second control signal K2, so that the fan starts to run, realizing that the fan starts only when the control signal is stable and effective, preventing misoperation. In the system power-off process, when the voltage of the first control signal K1 decreases and is lower than the first preset voltage value, the input side of the isolation control module 101 is cut off, the output end stops outputting the second control signal K2, causing the power conversion module 102 to stop outputting the third control signal K3, and the voltage clamping module 103 outputs a stop signal before the power conversion module 102 stops receiving the second control signal K2, for example, a threshold is set when the power supply voltage U0 gradually decreases, and the fan stops running when the threshold is reached. In this way, the fan can be actively turned off before the control signal fails, preventing it from continuing to run when the control fails but the power supply is still available, improving the safety and stability of the system.

[0057] The technical effect of the embodiment is that, through the setting of the isolation control module 101, the second control signal K2 can be output only after the first control signal K1 reaches the preset voltage threshold in the system power-on process, thereby avoiding the fan from starting too early when the control signal is not stable; in the system power-off process, the second control signal K2 can be actively stopped from being output before the control signal is lower than the preset threshold, preventing the fan from continuing to run when the control signal has failed but the power supply is still available. This design significantly improves the safety and controllability of the fan operation, ensuring the stability and reliability of the entire system during power switching.

[0058] As an example of the isolation control module 101, as shown inFigure 3 As shown, the isolation control module 101 comprises a first biasing module 111, a first switching module 112, and an optocoupler module 113, the optocoupler module 113 comprising a light-emitting diode and a photo triode, the anode of the light-emitting diode being the input end of the input port, the cathode of the light-emitting diode being connected to the input end of the first switching module 112, the control end of the first switching module 112 and the first end of the first biasing module 111 being commonly connected as the output end of the input port, the output end of the first switching module 112 and the first end of the first biasing module 111 being commonly connected to the ground, the collector of the photo triode being the input end of the output port, and the emitter of the photo triode being the output end of the output port.

[0059] The optocoupler module 113 comprises a light-emitting diode and a photo triode, the light-emitting diode being configured to receive an input current and emit a light signal, and the photo triode being configured to receive the light signal emitted by the light-emitting diode and turn on, thereby outputting a second control signal K2 and achieving electrical isolation between the input end and the output end. The first biasing module 111 is configured to provide a voltage bias or trigger level for the control end of the first switching module 112, and is usually composed of a voltage division network composed of one or more resistors or a pull-up / pull-down resistor; the first end of the first biasing module 111 is commonly connected to the control end of the first switching module 112 to ensure that the input control signal can accurately control the switching action. The first switching module 112 is configured to control whether the light-emitting diode in the optocoupler turns on or not according to the level state of the first control signal K1, and can be composed of an NPN triode or a MOSFET; when the first control signal K1 reaches a certain voltage value (i.e., a first preset voltage value), the first switching module 112 turns on, making the light-emitting diode turn on, and the photo triode turns on after receiving the light signal, thereby outputting the second control signal K2; when the first control signal K1 is lower than the voltage value, the first switching module 112 is cut off, the light-emitting diode does not emit light, and the photo triode remains in an off state, and the output end has no second control signal K2 output. By setting the control threshold value through the first biasing module 111, the first control signal K1 drives the first switching module 112 to control whether the light-emitting diode turns on or not; and then the second control signal K2 is output or interrupted through the on-off state of the photo triode, thereby achieving precise control and safe isolation between the control side and the power side.

[0060] The technical effect of the embodiment is that by arranging the first biasing module 111, the first switching module 112, and the optocoupler module 113 in the isolation control module 101, the on-off state of the optocoupler can be accurately controlled when the first control signal K1 reaches the set voltage threshold, thereby achieving reliable isolation and transmission of the control signal; this structure not only improves the stability and accuracy of the control signal response, but also effectively avoids the problem of false triggering caused by level fluctuation or interference, thereby ensuring the controlled operation of the fan during power-on and power-off processes and improving the safety, reliability, and anti-interference ability of the circuit.

[0061] As an example of the connection relationship between the voltage clamping module 103 and the power conversion module 102, the first terminal of the voltage clamping module 103 is connected to the power supply voltage U0, the second terminal of the voltage clamping module 103 and the first terminal of the power conversion module 102 are both connected to the output terminal of the isolation control module 101, the third terminal of the voltage clamping module 103 and the second terminal of the power conversion module 102 are both connected to ground, and the control terminal of the power conversion module 102 is connected to the output terminal of the isolation control module 101. During the power-on process, after the voltage value of the first control signal K1 rises to the first preset voltage value, the voltage clamping module 103 pulls up and clamps the third control signal K3 and outputs a start signal. During the power-off process, before the voltage value of the first control signal K1 drops to less than the first preset voltage value, the voltage clamping module 103 pulls down and clamps the third control signal K3 and outputs a stop signal.

[0062] The voltage clamping module 103 has its first terminal connected to the power supply voltage U0 (e.g., 24V) to monitor the fan's power supply voltage status. Its second terminal is connected to both the first terminal of the power conversion module 102 and the output terminal of the isolation control module 101, and is used for voltage clamping control of the PWM control signal. Its third terminal is grounded with the second terminal of the power conversion module 102, forming a complete current loop. The control terminal of the power conversion module 102 receives the second control signal K2 output from the isolation control module 101 and outputs a third control signal K3 based on this signal, thereby driving the fan to start and stop. Its first and second terminals are respectively connected to the second and third terminals of the voltage clamping module 103 to output the third control signal K3 (PWM control signal), which is the fan's start or stop signal. During power-on, the voltage of the first control signal K1 output by the control chip gradually increases. When it reaches a preset threshold (e.g., 2.7V), the isolation control module 101 is turned on and outputs the second control signal K2. At this point, the first control signal K1 has stabilized, and the voltage clamping module 103 pulls up the third control signal K3, causing the power conversion module 102 to output a high-level signal as the fan's start signal. This delayed pull-up design ensures that the fan only starts running after the control signal has stabilized, preventing malfunctions before the control signal is established. During power-down, before the first control signal K1 begins to decay but has yet to drop to the failure level (i.e., below the first preset voltage value), the voltage clamping module 103 acts in advance based on the power supply voltage, actively pulling down the third control signal K3 to a reference potential (such as ground potential), thereby outputting a fan stop signal in advance, ensuring the fan safely stops operating before control failure. This solution effectively prevents the fan from continuing to run after the control signal disappears.

[0063] The technical effect of the embodiment is that the voltage clamping module 103 can pull up or pull down the output of the power conversion module 102 when the control signal reaches or is lower than the preset voltage threshold, so as to realize accurate control of the fan start signal and the stop signal. The technical solution effectively avoids the problems of early start of the fan when the control signal is not stable during power-on and continuous operation of the fan after the control signal is invalid during power-off, and significantly improves the safety, response accuracy and system stability of the fan operation.

[0064] As an embodiment, as shown in Figure 4 The power conversion module 102 includes a second biasing module 121 and a second switching module 122. The first end of the second biasing module 121 and the control end of the second switching module 122 are connected together as the control end of the power conversion module 102. The first end of the second switching module 122 is the first end of the power conversion module 102. The second end of the second biasing module 121 and the second end of the second switching module 122 are connected together as the second end of the power conversion module 102.

[0065] The power conversion module 102 of the fan speed regulation circuit includes a second biasing module 121 and a second switching module 122. The second biasing module 121 is used to control the conduction or non-conduction of the third control signal K3 according to the second control signal K2 output by the isolation control module 101, so as to realize the start-stop control of the fan. Specifically, the first end of the second biasing module 121 and the control end of the second switching module 122 are connected together to form the control end of the power conversion module 102, which receives the second control signal K2 output by the isolation control module 101. The second biasing module 121 is used to provide a level bias for the second switching module 122 to control the conduction and non-conduction of the second switching module 122. The second biasing module 121 can be composed of a group of pull-up or pull-down resistors, filter capacitors, or resistor networks to ensure that the second switching module 122 remains in the off state when the control signal is invalid. The second switching module 122 is a power switching device, such as an NPN triode or an N-type MOSFET tube. The first end of the second switching module 122 is the first end of the power conversion module 102, which is connected to the voltage clamping module 103 and the PWM control signal path. The second end of the second switching module 122 is the second end of the power conversion module 102, which is connected to the ground. The control end of the second switching module 122 is connected to the second biasing module 121 to receive and respond to the second control signal K2. When the control end receives the valid second control signal K2 from the isolation control module 101, the second switching module 122 is turned on, and the third control signal K3 forms an effective start signal to drive the fan to run. When the second control signal K2 is invalid or at a low level, the second switching module 122 is turned off, and the output end is pulled low to form a stop signal for the fan, thereby realizing the disconnection control of the fan.

[0066] The technical effect of the embodiment is that: by setting the second biasing module 121 and the second switching module 122, the fan starting and stopping signals can be quickly responded and stably controlled; the second biasing module 121 provides a level reference, effectively avoiding false triggering; the second switching module 122 realizes accurate conduction or cut-off according to the control signal, thereby ensuring the fan to run under controlled conditions; the technical solution improves the control reliability, response speed and anti-interference ability of the fan speed regulation circuit, and ensures the system to stably and safely drive the fan to work during power-on and power-off processes.

[0067] As an embodiment, as shown in Figure 5 The voltage clamping module 103 includes a first voltage clamping module 131 and a second voltage clamping module 132, the first end of the first voltage clamping module 131 and the first end of the second voltage clamping module 132 are commonly connected as the first end of the voltage clamping module 103, the second end of the first voltage clamping module 131 and the second end of the second voltage clamping module 132 are commonly connected as the second end of the voltage clamping module 103, and the third end of the first voltage clamping module 131 and the third end of the second voltage clamping module 132 are commonly connected as the third end of the voltage clamping module 103; during the power-on process, after the voltage value of the first control signal K1 rises to the first preset voltage value, the first voltage clamping module 131 outputs the starting signal after pulling up and clamping the third control signal K3; during the power-off process, before the voltage value of the first control signal K1 decreases to less than the first preset voltage value, the second voltage clamping module 132 outputs the stopping signal after pulling down and clamping the third control signal K3.

[0068] The voltage clamping module 103 includes a first voltage clamping module 131 and a second voltage clamping module 132, which are used to pull up or pull down the fan control signal during system power-on and power-off, respectively, to prevent the fan from starting or continuously running in an abnormal state. During power-on, as the first control signal K1 output by the control chip increases in voltage, when it reaches a set first preset voltage value (such as 2.7V), the first voltage clamping module 131 responds, releases the pull-up path, pulls up the third control signal K3 to the effective level, and thus outputs the fan start signal, ensuring that the fan only runs after the control signal is stable and effective. During power-off, when the system gradually powers off and the first control signal K1 has not completely failed (still higher than the first preset voltage value), the second voltage clamping module 132 actively triggers during the power supply voltage U0 drop, pulls down the third control signal K3 through the pull-down path, outputs the fan stop signal, and ensures that the fan is powered off in time to prevent abnormal continuous operation due to delayed control signal failure. The first voltage clamping module 131 can include components such as a voltage stabilizing diode and a pull-up resistor, and the voltage stabilizing tube sets the voltage threshold, which is released only when the system voltage reaches a stable state. The second voltage clamping module 132 is usually composed of a voltage dividing resistor network, a comparison component (such as a transistor or an operational amplifier), etc., to realize the conduction of the pull-down path when the power supply voltage U0 drops to a preset value.

[0069] The technical effect of the embodiment is that by setting the first voltage clamping module 131 and the second voltage clamping module 132, the power-on pull-up clamping and power-off pull-down clamping control of the third control signal K3 are realized in the fan speed regulation circuit, ensuring that the fan only starts after the first control signal K1 reaches the set voltage threshold, avoiding misoperation when the control signal is unstable; and the control signal can be pulled down in time before power-off, realizing the advance power-off of the fan, effectively improving the controllability and response accuracy of fan start and stop, and enhancing the safety, reliability and anti-interference ability of the circuit in a dynamic power environment.

[0070] As an embodiment, as shown in Figure 6 The first voltage clamping module 131 includes a first current limiting module 141, a first voltage stabilizing module 142, and a second voltage stabilizing module 143. The first end of the first current limiting module 141 is the first end of the first voltage clamping module 131, the second end of the first current limiting module 141 is connected to the input end of the first voltage stabilizing module 142, the output end of the first voltage stabilizing module 142 and the input end of the second voltage stabilizing module 143 are commonly connected as the second end of the first voltage clamping module 131, and the output end of the second voltage stabilizing module 143 is the third end of the first voltage clamping module 131.

[0071] The first voltage clamping module 131 comprises a first current limiting module 141, a first voltage stabilizing module 142 and a second voltage stabilizing module 143, and is configured to perform pull-up clamping control on the fan control signal during system power-on, so as to realize controlled delay triggering of fan starting. The first end of the first current limiting module 141 is connected to the fan power voltage U0 (for example, 24V), constituting the first end of the first voltage clamping module 131, and is configured to limit the input current to prevent current mutation from damaging the subsequent components. The output end of the first voltage stabilizing module 142 is connected to the input end of the second voltage stabilizing module 143, constituting the second end of the first voltage clamping module 131, and is connected to the power conversion module 102 and the third control signal K3 path. The first voltage stabilizing module 142 is configured to perform pull-up control on the third control signal K3 path after the voltage of the first control signal K1 reaches a first preset voltage value (for example, 2.7V), and output a starting signal. The output end of the second voltage stabilizing module 143 constitutes the third end of the first voltage clamping module 131, and is configured to output a stable pull-up voltage in cooperation with the first voltage stabilizing module 142. During power-on, the first control signal K1 output by the control chip gradually rises, and when the voltage rises to the first preset voltage value, the first voltage stabilizing module 142 starts to output a stable voltage, and after a certain delay, applies a clamping voltage to the third control signal K3 in a pull-up manner, so as to ensure that the fan starts to run only after the control signal is stable, and avoid misstarting caused by transient jitter or power supply fluctuation. In particular, the action time of the first voltage stabilizing module 142 is later than the time when the first control signal K1 rises to the preset value, that is, it has a certain delay characteristic, so as to further improve the robustness of the control and the system stability.

[0072] The technical effect of the embodiment is that, by means of current limiting protection, hierarchical voltage stabilization and delay pull-up, the delay and stable starting control of the fan during power-on are realized, the mistriggering problem in the initial unstable stage of the control signal is effectively avoided, and the safety, response accuracy and operation reliability of the fan speed regulation system in a dynamic power supply environment are improved.

[0073] As an embodiment, as Figure 7As shown, the second voltage clamping module 132 includes a first voltage dividing module 151, a second voltage dividing module 152, a third switch module 154, a second current limiting module 153, and a fourth switch module 155. The first end of the first voltage dividing module 151 and the first end of the second current limiting module 153 are connected together as the first end of the second voltage clamping module 132. The second end of the first voltage dividing module 151 is connected to the first end of the second voltage dividing module 152 and the control end of the third switch module 154, respectively. The second end of the second current limiting module 153 is connected to the first end of the third switch module 154 and the control end of the fourth switch module 155, respectively. The first end of the fourth switch module 155 is the second end of the second voltage clamping module 132. The second end of the second voltage dividing module 152, the second end of the third switch module 154, and the second end of the fourth switch module 155 are connected together as the third end of the second voltage clamping module 132.

[0074] The first voltage dividing module 151 is used for preliminary voltage division of the 24V power supply voltage U0 to obtain a reference voltage varying with the power supply voltage U0. The first voltage dividing module 151 can be composed of a resistor network (such as R7) and is connected in series with the second voltage dividing module 152 to form a detection path. The second voltage dividing module 152 is connected in series with the first voltage dividing module 151 and is used for setting a power-off threshold of the detection system. The power-off threshold is designed according to the effective voltage of the first control signal K1 and is greater than the effective voltage of the first control signal K1. The second voltage dividing module 152 and the first voltage dividing module 151 constitute a complete voltage divider, and the output end thereof determines the level logic used for controlling the pull-down action. The control end of the third switch module 154 is connected to the voltage dividing output. When it is detected that the power supply voltage U0 is higher than the power-off threshold, the third switch module 154 is turned on. When the power supply voltage U0 is lower than the power-off threshold, the third switch module 154 is automatically turned off. The control logic ensures that the third switch module 154 is turned on to pull the pull-down path when the power supply is stable. The control is automatically released when the power supply is powered off, and the pull-down is started. The third switch module 154 can be an NPN transistor, an NMOS or the like. The second current limiting module 153 provides current limiting protection for the control path of the third switch module 154 and the fourth switch module 155 to prevent overcurrent from impacting the control end during the power-off process. The second current limiting module 153 is usually a current limiting resistor. The control end of the fourth switch module 155 is connected between the second current limiting module 153 and the third switch module 154. When the third switch module 154 is turned off, the potential at the control end thereof is pulled high, thereby turning on the fourth switch module 155. After being turned on, the PWM signal is pulled down to the reference ground (COM), and the output stop signal is output. The third switch module 154 can be an NPN transistor or an NMOS device. When the system is normally powered, the 24V voltage forms a control level higher than the threshold through the first voltage dividing module 151 and the second voltage dividing module 152, maintains the third switch module 154 turned on, and turns off the fourth switch module 155, so that the fan normally operates. During the system power-off process, the 24V voltage is reduced to below the threshold set by the voltage division. The third switch module 154 is turned off due to insufficient voltage at the control end. At this time, the second current limiting module 153 and the fourth switch module 155 form a conduction loop, the fourth switch module 155 is turned on, the PWM signal line is forced to be pulled down to the COM potential, and the fan stop signal is output. Although the first control signal K1 can still be valid at this time, the fan stops operating due to the pull-down of the PWM signal. The whole process is still completed in a controllable state, and the fan is prevented from malfunctioning due to abnormal power supply before the control signal is invalid.

[0075] The technical effect of the embodiment is that the power-off threshold is set by the first voltage dividing module 151 and the second voltage dividing module 152, and the dynamic response circuit is constructed by the switch control structure, so that the fan control signal can be automatically pulled down when the power supply voltage U0 drops below the safety threshold, the fan is turned off in advance, and the misoperation problem caused by the delayed failure of the control signal is avoided; the technical scheme improves the safety, accuracy and power-off response speed of the fan control, and has good engineering practical value.

[0076] The working process of the circuit structure provided by the technical scheme will be described below. Figure 8 The working process of the circuit structure provided by the technical scheme will be described below.

[0077] The isolation control module 101 includes a first bias module 111, a first switch module 112, and an optocoupler module 113. The first bias module 111 includes a resistor R2 and a capacitor C1. The first switch module 112 is a transistor Q1. The optocoupler module 113 is an optocoupler PC1. The isolation control module 101 also includes resistors R1, C2, R3, R4, R5, and C3. The power conversion module 102 includes capacitor C4, resistor R10, transistor Q2, and capacitor C5. The voltage clamping module 103 includes resistors R6, R7, R8, R9, and R11, Zener diodes Z1 and Z2, and capacitors C6 and C7. C7, transistor Q3, and transistor Q4; the connections of each device are as follows: the first terminal of resistor R1 receives the first control signal K1; the second terminal of resistor R1 is connected to the first terminal of resistor R2, the first terminal of capacitor C1, and the base of transistor Q1; the collector of transistor Q1 is connected to the first terminal of capacitor C2 and the first terminal of resistor R3; the second terminals of resistor R2, capacitor C1, the emitter of transistor Q1, and capacitor C2 are grounded; the second terminal of resistor R3 is connected to the second terminal of resistor R4, the second terminal of capacitor C3, and the cathode of the light-emitting diode in optocoupler PC1; the first terminals of resistor R4, capacitor C3, and the optocoupler... In device PC1, the anode of the LED is connected to a 5V voltage. The collector of the phototransistor in optocoupler PC1 is connected to the first terminal of resistor R5. The second terminals of resistor R5, the first terminals of resistors R6 and R7, and the first terminal of resistor R8 are connected to a 24V power supply. The emitter of the phototransistor in optocoupler PC1 is connected to the first terminal of capacitor C4, the first terminal of resistor R10, and the base of transistor Q2. The collector of transistor Q2, the first terminal of capacitor C5, the anode of Zener diode Z1, the cathode of Zener diode Z2, and the collector of transistor Q4 are connected to output a PWM control signal. The second terminal of resistor R6 is connected to the [missing information - likely a specific resistor or component]. The cathode is connected to the first terminal of resistor R9. The second terminal of resistor R9 is connected to the first terminals of resistors R11 and R12. The second terminal of resistor R12 is connected to the first terminal of capacitor C6 and the base of transistor Q3. The second terminal of resistor R8 is connected to the collector of transistor Q3, the first terminal of capacitor C7, and the base of transistor Q4. The second terminals of capacitor C4, resistor R10, transistor Q2 emitter, capacitor C5, Zener diode Z2 anode, resistor R11, capacitor C6, transistor Q3 emitter, capacitor C7, and transistor Q4 are all connected to ground.

[0078] The working process of the circuit structure is as follows: the fan control signal Control output by the control chip controls the conduction and shutdown of the primary side diode of the optocoupler PC1 through the transistor Q1. When Control is at a low level, the primary side diode of the optocoupler PC1 is off, the secondary side transistor of the optocoupler PC1 is not conductive, and thus the transistor Q2 is not conductive. Under the action of the stabilizing tube Z1 and the stabilizing tube Z2, the PWM signal is output at a 5.1V level, and at this time, the fan is running. When Control is at a high level, the primary side diode of the optocoupler PC1 is conductive, the secondary side transistor of the optocoupler PC1 is conductive, the transistor Q2 is conductive, and the PWM signal is pulled down to the COM potential, and the fan stops running. By inputting a pulse Control signal with a duty cycle change, the high and low levels of the PWM output can be controlled, and thus the fan speed can be controlled. The Control signal is output by the control chip, and the level is mostly 3.3V. As shown in Figure 9 , during the system power-on process, the voltage of the Control signal rises to 2.7V as an effective high level, and at this time, the 24V power supply voltage rises from 0 to 13-15V to output a high level, that is, the fan can be driven to run. As shown in Figure 9 , during the system power-down process, when the voltage of the Control signal drops from 3.3V to below the effective high level of 2.7V, the 24V power supply voltage drops to 17-19V; and when the Control signal is at a low level, the PWM control signal is at a high level, so there is an uncontrolled situation of fan running during the power-on and power-down processes. As shown in Figure 8 , in order to solve the technical problem, in the power-on process, the 24V power supply voltage must reach the stabilizing value VZ of the stabilizing tube Z1 to pull up the level of the PWM control signal, and when the 24V power supply voltage reaches the stabilizing value VZ of the stabilizing tube Z1, the voltage of the Control signal has reached the effective voltage 2.7V, and the high level has been established, at this time, the fan is controlled and will not run abnormally. In the power-down process, the remaining voltage of the 24V power supply voltage is detected through the voltage dividing resistor R7, the resistor R9 and the resistor R11, the dropout threshold VD of the 24V power supply voltage is designed by adjusting the resistance values of the resistor R7, the resistor R9 and the resistor R11, when the remaining voltage of the 24V power supply voltage reaches the dropout threshold VD, the transistor Q3 is off, the transistor Q4 is conductive, the PWM level is pulled down to the COM potential, and the fan stops running, and at this time, the voltage of the Control signal is still above the effective voltage 2.7V, and the high level still exists, and the fan is controlled.

[0079] Embodiment Two

[0080] The utility model embodiment second aspect provides a fan control system, as shown in Figure 11 , the fan control system includes the fan speed regulation circuit and control chip 200 of first aspect, and the control chip 200 outputs the first control signal to the isolation control module 101.

[0081] Wherein, on the basis of the fan speed regulation circuit provided in the first aspect, the control chip 200 is further integrated, the control chip 200 is used as a core control unit, and a first control signal is output to the isolation control module 101 according to the system operation state or the heat dissipation demand, so that precise control of fan start-stop and speed is realized. By using the control chip 200 in cooperation with the fan speed regulation circuit, not only automatic and intelligent fan control can be realized, but also the response speed and control accuracy of the overall system can be improved.

[0082] Embodiment three

[0083] The utility model embodiment third aspect provides a fan, such as Figure 12 As shown, the fan includes the fan control system and the actuating mechanism 300 of the second aspect, and the actuating mechanism 300 receives the third control signal output by the power conversion module 102.

[0084] Wherein, the actuating mechanism 300 is the drive unit of the fan, such as motor and related driving parts, for receiving the third control signal output by the power conversion module 102, and realizing the start-stop and speed regulation control of the fan.

[0085] Through the above structure, the fan not only has basic speed regulation and start-stop function, but also can realize safety protection during system power fluctuation or power-on and power-off process, and the reliability and intelligence of fan operation are improved.

[0086] The above embodiments are only used to illustrate the technical solutions of the utility model, and not to limit them; although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the utility model, and all should be included in the protection scope of the utility model.

Claims

1. A fan speed regulation circuit, characterized by, include: An isolation control module is connected to the power supply voltage and the first control signal respectively. After electrically isolating the first control signal, it outputs the second control signal. A power conversion module, which is connected to the output terminal of the isolation control module, is used to output a third control signal according to the second control signal, the third control signal including a start signal and a stop signal; A voltage clamping module, which is connected to the power conversion module and the power supply voltage respectively, is used to adjust the power conversion module to output the start signal after receiving the second control signal during the power-on process, so as to control the fan to start running, and to adjust the power conversion module to output the stop signal before stopping receiving the second control signal during the power-off process, so as to control the fan to stop running.

2. The fan speed regulation circuit of claim 1, wherein, The isolation control module includes an input port and an output port. The input terminal of the input port receives a first voltage, the output terminal of the input port receives a first control signal, the input terminal of the output port receives the power supply voltage, and the output terminal of the output port is connected to the output terminal of the power conversion module. During the power-on process, the isolation control module outputs a second control signal when the voltage value of the first control signal rises to a first preset voltage value; During the power-down process, the isolation control module stops outputting the second control signal when the voltage value of the first control signal drops below the first preset voltage value.

3. The fan speed regulation circuit of claim 2, wherein, The isolation control module includes a first bias module, a first switch module, and an optocoupler module. The optocoupler module includes a light-emitting diode (LED) and a phototransistor. The anode of the LED is the input terminal of the input port, and the cathode of the LED is connected to the input terminal of the first switch module. The control terminal of the first switch module and the first terminal of the first bias module are jointly connected to the output terminal of the input port. The output terminal of the first switch module and the first terminal of the first bias module are jointly connected to ground. The collector of the phototransistor is the input terminal of the output port, and the emitter of the phototransistor is the output terminal of the output port.

4. The fan speed regulation circuit of claim 2, wherein, The first terminal of the voltage clamping module is connected to the power supply voltage. The second terminal of the voltage clamping module and the first terminal of the power conversion module are both connected to the output terminal of the isolation control module. The third terminal of the voltage clamping module and the second terminal of the power conversion module are both connected to ground. The control terminal of the power conversion module is connected to the output terminal of the isolation control module. During the power-on process, when the voltage value of the first control signal rises to the first preset voltage value, the voltage clamping module then pulls up and clamps the third control signal before outputting the start signal; During the power-down process, before the voltage value of the first control signal drops below the first preset voltage value, the voltage clamping module pulls down and clamps the third control signal before outputting the stop signal.

5. The fan speed regulation circuit of claim 4, wherein, The voltage clamping module comprises a first voltage clamping module and a second voltage clamping module, a first end of the first voltage clamping module and a first end of the second voltage clamping module are connected to a first end of the voltage clamping module, a second end of the first voltage clamping module and a second end of the second voltage clamping module are connected to a second end of the voltage clamping module, and a third end of the first voltage clamping module and a third end of the second voltage clamping module are connected to a third end of the voltage clamping module. In the power-on process, when the voltage value of the first control signal rises to a first preset voltage value, the first voltage clamping module performs pull-up clamping on the third control signal and then outputs the start signal. In the power-off process, when the voltage value of the first control signal decreases to less than the first preset voltage value, the second voltage clamping module performs pull-down clamping on the third control signal and then outputs the stop signal.

6. The fan speed regulation circuit of claim 5, wherein, The first voltage clamping module comprises a first current limiting module, a first voltage stabilizing module, and a second voltage stabilizing module, a first end of the first current limiting module is a first end of the first voltage clamping module, a second end of the first current limiting module is connected to an input end of the first voltage stabilizing module, an output end of the first voltage stabilizing module and an input end of the second voltage stabilizing module are connected to a second end of the first voltage clamping module, and an output end of the second voltage stabilizing module is a third end of the first voltage clamping module.

7. The fan speed regulation circuit of claim 5, wherein, The second voltage clamping module comprises a first voltage dividing module, a second voltage dividing module, a third switch module, a second current limiting module, and a fourth switch module, a first end of the first voltage dividing module and a first end of the second current limiting module are connected to a first end of the second voltage clamping module, a second end of the first voltage dividing module is connected to a first end of the second voltage dividing module and a control end of the third switch module respectively, a second end of the second current limiting module is connected to a first end of the third switch module and a control end of the fourth switch module respectively, a first end of the fourth switch module is a second end of the second voltage clamping module, and a second end of the second voltage dividing module, a second end of the third switch module, and a second end of the fourth switch module are connected to a third end of the second voltage clamping module.

8. The fan speed regulation circuit of claim 4, wherein, The power conversion module comprises a second biasing module and a second switch module, a first end of the second biasing module and a control end of the second switch module are connected to a control end of the power conversion module, a first end of the second switch module is a first end of the power conversion module, and a second end of the second biasing module and a second end of the second switch module are connected to a second end of the power conversion module.

9. A fan control system, characterized by The fan control system comprises the fan speed regulation circuit and the control chip according to any one of claims 1 to 8, and the control chip outputs a first control signal to the isolation control module.

10. A fan, characterized by The fan comprises the fan control system according to claim 9 and an execution mechanism, and the execution mechanism receives a third control signal output by the power conversion module.

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