Cooling fan control circuit and cooling fan

Abstract

The utility model discloses a cooling fan control circuit and a cooling fan, and the embodiment of the utility model can not start the fan under the condition of lower temperature, so that the condition that the fan is burnt out due to forced start of the fan when a bearing of the fan is frozen due to lower temperature is avoided, and the service life of the cooling fan is prolonged. The technical problem that in the prior art, when a fan is started under the condition of low temperature, the fan is prone to being burnt down is solved. When the temperature is high, the fan can be controlled to be started, the rotating speed of the fan can be automatically adjusted according to the temperature, the heat dissipation effect of the fan is guaranteed, the service life of the fan is prolonged, and the energy-saving effect is achieved.

Description

Technical Field

[0001] The utility model relates to the field of automation, in particular to a cooling fan control circuit and a cooling fan. Background Art

[0002] Currently, some circuit modules, such as high-power power supplies or high-performance chips, generate significant heat during operation. Relying solely on natural cooling within the circuit module housing would increase the module's size and weight, hindering miniaturization. Therefore, most cooling methods currently employed include water cooling or air cooling. Air cooling, in particular, has gained widespread adoption due to its ease of installation, excellent cooling performance, and its potential to reduce device size and weight.

[0003] However, when using air cooling, if the fan is not operating and the ambient temperature is low, the fan bearings may freeze. If the fan is started at this time, the fan motor needs to output greater torque to overcome the resistance, and the motor current increases, which can easily cause the fan to burn out. Utility Model Content

[0004] The utility model provides a heat dissipation fan control circuit and a heat dissipation fan, which are used to solve the technical problem in the prior art that the fan is easily burned when the fan is started under low temperature conditions.

[0005] In a first aspect, an embodiment of the present utility model provides a cooling fan control circuit, comprising a voltage output module, a voltage comparison module, and a voltage stabilization adjustment module;

[0006] The first end of the voltage output module is connected to the power supply, the second end of the voltage output module is connected to the first end of the voltage comparison module, and is used to output a reference voltage signal to the voltage comparison module; the third end of the voltage output module is connected to the second end of the voltage comparison module, and is used to output a first input voltage signal to the voltage comparison module;

[0007] The third terminal of the voltage comparison module is connected to the first terminal of the voltage stabilization adjustment module. The voltage comparison module is configured to convert the first input voltage signal into a second input voltage signal. When the reference voltage signal is greater than the second input voltage signal, the voltage comparison module outputs a low-level signal to the voltage stabilization adjustment module. When the reference voltage signal is less than the second input voltage signal, the voltage comparison module outputs a high-level signal to the voltage stabilization adjustment module. The voltage value of the second input voltage signal is positively correlated with the temperature value.

[0008] The second end of the voltage stabilization adjustment module is connected to the power supply, and the third end of the voltage stabilization adjustment module is connected to the control end of the fan. The voltage stabilization adjustment module is used to not output the control signal to the control end of the fan when receiving the low-level signal; and to output the control signal to the fan in real time according to the temperature when receiving the high-level signal, and the control signal is used to control the speed of the fan.

[0009] Wherein, the voltage output module includes a voltage stabilizing submodule and a voltage dividing submodule;

[0010] The first end of the voltage stabilizing submodule is connected to the power supply, and the second end of the voltage stabilizing submodule is connected to the first end of the voltage dividing submodule and the second end of the voltage comparison module. The voltage stabilizing submodule is configured to output a first input voltage signal with a constant voltage value to the voltage dividing submodule and the voltage comparison module after stabilizing the power supply voltage signal provided by the power supply;

[0011] The second end of the voltage dividing submodule is used to be connected to the first end of the voltage comparison module. The voltage dividing submodule is used to divide the first input voltage signal and then output the reference voltage signal to the voltage comparison module.

[0012] The voltage stabilizing submodule includes a first voltage stabilizing tube, a controllable precision voltage stabilizing source, a first resistor, a second resistor, a third resistor, a fourth resistor, and a fifth resistor;

[0013] The negative electrode of the first voltage-stabilizing diode is connected to the power supply, the positive electrode of the first voltage-stabilizing diode is connected to the first end of the first resistor, the second end of the first resistor is connected to the cathode of the controllable precision voltage-stabilizing source, the first end of the second resistor and the first end of the voltage divider module, the second end of the second resistor is connected to the reference level of the controllable precision voltage-stabilizing source and the first end of the third resistor; the anode of the controllable precision voltage-stabilizing source and the second end of the third resistor are grounded.

[0014] Among them, the voltage divider module includes a fourth resistor and a fifth resistor, the first end of the fourth resistor is connected to the second end of the voltage comparison module, the second end of the fourth resistor is connected to the first end of the voltage comparison module and the first end of the fifth resistor, and the second end of the fifth resistor is grounded.

[0015] Wherein, the voltage comparison module includes a first temperature-sensing resistor, a sixth resistor, a first comparator and a seventh resistor;

[0016] A first end of the first temperature-sensing resistor is connected to the third end of the voltage output module, a second end of the first temperature-sensing resistor is connected to the first end of the sixth resistor, the non-inverting input end of the first comparator, and the first end of the seventh resistor, and a second end of the sixth resistor is grounded;

[0017] The inverting input terminal of the first comparator is connected to the second terminal of the voltage output module, and the output terminal of the first comparator is connected to the second terminal of the seventh resistor and the first terminal of the voltage regulating module.

[0018] Wherein, the first temperature-sensitive resistor is a negative temperature coefficient resistor.

[0019] The voltage regulating and adjusting module includes a first diode, an eighth resistor, a ninth resistor, a linear low voltage difference voltage regulating circuit, a tenth resistor, a second temperature sensing resistor and a first capacitor;

[0020] The negative electrode of the first diode is connected to the third end of the voltage comparison module, the first end of the eighth resistor is connected to the power supply and the power supply end of the linear low voltage difference voltage regulator circuit, the second end of the eighth resistor is connected to the ninth resistor, the enable end of the linear low voltage difference voltage regulator circuit and the positive electrode of the first diode, the voltage regulation end of the linear low voltage difference voltage regulator circuit is connected to the first end of the second temperature-sensitive resistor and the second end of the tenth resistor, the first end of the tenth resistor is connected to the output end of the linear low voltage difference voltage regulator circuit, the first end of the first capacitor and the control end of the fan, the second end of the ninth resistor, the second end of the second temperature-sensitive resistor and the second end of the first capacitor are all grounded.

[0021] Wherein, the second temperature-sensitive resistor is a negative temperature coefficient resistor.

[0022] Wherein, the linear low voltage difference voltage stabilizing circuit is a MIC29302BU chip.

[0023] In a second aspect, an embodiment of the present invention provides a heat dissipation fan, comprising the heat dissipation fan control circuit described in the first aspect.

[0024] As described above, the present invention discloses a cooling fan control circuit and a cooling fan. Embodiments of the present invention are capable of not activating the fan when the temperature is low, thus preventing the fan from burning out due to forced activation when the fan bearing freezes at low temperatures. This resolves the prior art technical problem of fans easily burning out when activated at low temperatures. Furthermore, when the temperature is high, the present invention controls the fan to activate and automatically adjusts the fan speed based on the temperature to ensure effective cooling, while also extending the fan's service life and achieving energy savings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The present invention provides a schematic structural diagram of a cooling fan control circuit according to an embodiment of the present invention.

[0026] Figure 2 This is a structural diagram of another cooling fan control circuit provided by an embodiment of the present utility model.

[0027] Figure 3 This is a circuit schematic diagram of a cooling fan control circuit provided by an embodiment of the present utility model.

[0028] Reference numerals:

[0029] Voltage output module 100, voltage comparison module 20, voltage regulation adjustment module 30, fan 40, power supply 50, voltage regulation sub-module 11, voltage divider sub-module 12, first voltage regulator D1, controllable precision voltage regulator U1, first resistor R1, second resistor R2, third resistor R3, fourth resistor R4, fifth resistor R5, first temperature-sensing resistor RT1, sixth resistor R6, first comparator U2, seventh resistor R7, first diode D2, eighth resistor R8, ninth resistor R9, linear low voltage difference voltage regulator circuit U3, tenth resistor R10, second temperature-sensing resistor RT2, first capacitor C1. DETAILED DESCRIPTION

[0030] To make the technical problems solved, the technical solutions adopted, and the technical effects achieved by the present invention more clearly understood, the technical solutions of the embodiments of the present invention are described in further detail below. Obviously, the embodiments described are only a portion of the embodiments of the present invention, not all of them. All other embodiments derived by those skilled in the art based on the embodiments of the present invention without creative effort are also within the scope of protection of the present invention.

[0031] In the description of this utility model, unless otherwise expressly specified or limited, the terms "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on the specific circumstances.

[0032] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0033] The present invention provides a cooling fan control circuit. Figure 1 As shown, Figure 1 1 is a schematic structural diagram of a cooling fan control circuit provided by an embodiment of the present utility model. The cooling fan control circuit provided by the embodiment of the present utility model includes a voltage output module 10 , a voltage comparison module 20 and a voltage regulation module 30 .

[0034] The first end of the voltage output module 10 is connected to the power supply 50, the second end of the voltage output module 10 is connected to the first end of the voltage comparison module 20, and is used to output a reference voltage signal to the voltage comparison module 20; the third end of the voltage output module 10 is connected to the second end of the voltage comparison module 20, and is used to output the first input voltage signal to the voltage comparison module 20.

[0035] In this embodiment, the voltage output module 10 is a module for outputting a voltage signal. Specifically, in this embodiment, the power supply 50 provides a power supply voltage for the voltage output module 10, and the voltage output module 10 then outputs a reference voltage signal and a first voltage input signal to the first end of the voltage comparison module 20 and the second end of the voltage comparison module 20 according to the power supply voltage provided by the power supply 50, respectively. The power supply 50 can be an independent voltage source or a voltage output by a power supply port of other circuits, etc., which will not be described in detail in this embodiment. Exemplarily, the voltage output module 10 can stabilize the power supply voltage and output the stabilized voltage signal as the first input voltage signal to the voltage comparison module 20; and after performing voltage conversion on the stabilized voltage signal, the converted voltage signal can be used as a reference voltage signal and output to the voltage comparison module 20.

[0036] The third end of the voltage comparison module 20 is connected to the first end of the voltage stabilization adjustment module 30. The voltage comparison module 20 is used to convert the first input voltage signal into a second input voltage signal. When the reference voltage signal is greater than the second input voltage signal, the voltage comparison module 20 outputs a low-level signal to the voltage stabilization adjustment module 30. When the reference voltage signal is less than the second input voltage signal, the voltage comparison module 20 outputs a high-level signal to the voltage stabilization adjustment module 30. The voltage value of the second input voltage signal is positively correlated with the temperature value.

[0037] In this embodiment, after the voltage output module 10 outputs the first input voltage signal and the reference voltage signal to the voltage comparison module 20, the voltage comparison module 20 converts the voltage value of the first input voltage signal to obtain a second input voltage signal, wherein the voltage value of the second voltage input signal is positively correlated with the temperature of the environment in which the voltage comparison module 20 is currently located, i.e., the higher the temperature, the higher the voltage value of the second voltage input signal, and the lower the temperature, the lower the voltage value of the second voltage input signal. It will also be understood that in this embodiment, the maximum voltage value of the second voltage input signal does not exceed the voltage value of the first input voltage signal.

[0038] After receiving the second input voltage signal, the voltage comparison module 20 compares the reference voltage signal with the second input voltage signal. If the reference voltage signal is greater than the second input voltage signal, the voltage comparison module 20 outputs a low-level signal to the voltage regulation and adjustment module 30. If the reference voltage signal is less than the second input voltage signal, the voltage comparison module 20 outputs a high-level signal to the voltage regulation and adjustment module 30. Since the voltage value of the second input voltage signal is positively correlated with the temperature value, that is, when the temperature value is a certain preset temperature value (or a certain preset temperature range), the voltage value of the second input voltage signal is equal to the voltage value of the reference voltage signal; when the temperature value is less than the preset temperature value (or a certain preset temperature range), the voltage value of the second input voltage signal is less than the voltage value of the reference voltage signal, and the voltage comparison module 20 outputs a low-level signal; when the temperature value is greater than the preset temperature value (or a certain preset temperature range), the voltage value of the second input voltage signal is greater than the voltage value of the reference voltage signal, and the voltage comparison module 20 outputs a high-level signal. The process of the voltage comparison module 20 comparing the reference voltage signal and the second input voltage signal can be implemented by a comparator.

[0039] The second end of the voltage stabilization and adjustment module 30 is connected to the power supply 50, and the third end of the voltage stabilization and adjustment module 30 is connected to the control end of the fan 40. The voltage stabilization and adjustment module 30 is used to not output a control signal to the control end of the fan 40 when a low-level signal is received; and to output a control signal to the fan 40 in real time according to the temperature when a high-level signal is received. The control signal is used to control the speed of the fan 40.

[0040] In this embodiment, the power supply 50 also supplies power to the voltage stabilization and adjustment module 30 to enable normal operation of the voltage stabilization and adjustment module 30. When the voltage stabilization and adjustment module 30 receives a low-level signal output by the voltage comparison module 20, it does not output a control signal to the control terminal of the fan 40, thereby disabling the fan 40. However, when the voltage stabilization and adjustment module 30 receives a high-level signal output by the voltage comparison module 20, it dynamically outputs a control signal to the fan 40 based on the current temperature change, thereby controlling the speed of the fan 40 in real time based on the temperature change. In this embodiment, since the voltage comparison module 20 outputs a low-level signal when the temperature is less than a preset temperature value (or within a preset temperature range), the preset temperature value can be set to a relatively low value, such as 0° (or the preset temperature range can be set to 0°-10°). Therefore, when the temperature is below 0°, the voltage stabilization and adjustment module 30 does not output a control signal to the fan 40, disabling the fan 40 from rotating. This prevents forced activation of the fan 40 when the bearings of the fan 40 freeze due to low temperatures, potentially causing the fan 40 to burn out. When the temperature is above 0° or above a certain temperature point, the voltage regulating and adjusting module 30 controls the fan 40 to start and automatically adjusts the operating voltage of the fan 40 according to the temperature, so that the speed of the fan 40 is kept within a certain range to ensure the heat dissipation effect of the fan 40.

[0041] Based on the above embodiment, the voltage output module 10 includes a voltage stabilizing submodule 11 and a voltage dividing submodule 12 .

[0042] The first end of the voltage stabilizing submodule 11 is connected to the power supply 50, and the second end of the voltage stabilizing submodule 11 is connected to the first end of the voltage dividing submodule 12 and the second end of the voltage comparison module 20. The voltage stabilizing submodule 11 is configured to stabilize the power voltage signal provided by the power supply 50 and output a first input voltage signal with a constant voltage value to the voltage dividing submodule 12 and the voltage comparison module 20.

[0043] In one embodiment, if Figure 2 As shown, Figure 2 This is a structural diagram of another cooling fan control circuit provided by an embodiment of the present utility model. Figure 2The medium voltage output module 10 includes a voltage stabilizing submodule 11 and a voltage dividing submodule 12. The voltage stabilizing submodule 11 is used to stabilize the power supply voltage signal output by the power supply 50 to obtain a reference voltage signal with a constant voltage value, and then output a first input voltage signal to the voltage dividing submodule 12 and the voltage comparison module 20. Exemplarily, the voltage stabilizing submodule 11 includes a controllable precision voltage stabilizing source. Controllable precision voltage stabilizing sources are widely used as power supply voltage regulators in power supply voltage stabilization circuits. They can generate stable voltage outputs under different operating currents, ensuring that the power supply can maintain a constant output voltage when the load changes and the input voltage fluctuates, thereby achieving the output of a first input voltage signal with a constant voltage value.

[0044] On the basis of the above embodiment, the voltage stabilizing submodule 11 includes a first voltage stabilizing diode D1, a controllable precision voltage stabilizing source U1, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4 and a fifth resistor R5;

[0045] The negative electrode of the first voltage-stabilizing diode D1 is connected to the power supply 50, the positive electrode of the first voltage-stabilizing diode D1 is connected to the first end of the first resistor R1, the second end of the first resistor R1 is connected to the cathode of the controllable precision voltage-stabilizing source U1, the first end of the second resistor R2 and the first end of the voltage divider module 12, the second end of the second resistor R2 is connected to the reference level of the controllable precision voltage-stabilizing source U1 and the first end of the third resistor R3; the anode of the controllable precision voltage-stabilizing source U1 and the second end of the third resistor R3 are grounded.

[0046] In one embodiment, if Figure 3 As shown, Figure 3 The circuit schematic diagram of a cooling fan control circuit provided by an embodiment of the present utility model, the voltage stabilizing submodule 11 includes a first voltage stabilizing tube D1, a controllable precision voltage stabilizing source U1, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4 and a fifth resistor R5. Since the voltage value of the power supply voltage +VCC may be a relatively high value, it is possible to reduce the power consumption of the first resistor R1 by selecting whether to connect the first voltage stabilizing tube D1. The controllable precision voltage stabilizing source U1, the first resistor R1, the second resistor R2 and the third resistor R3 constitute the main part of the voltage stabilizing submodule 11, R1 is a load resistor, and the second resistor R2 and the third resistor R3 are voltage divider resistors of the voltage stabilizing submodule 11. In one embodiment, by selecting appropriate resistance values, the cathode voltage of the controllable precision voltage stabilizing source U1 can be 5V, that is, the first input voltage signal is 5V, and the formula is:

[0047]

[0048] Among them, 2.5V is the internal voltage reference benchmark of the controllable precision voltage regulator U1.

[0049] The above is the specific working principle of the voltage stabilizing submodule 11 .

[0050] The second end of the voltage divider module 12 is used to connect to the first end of the voltage comparison module 20 . The voltage divider module 12 is used to divide the first input voltage signal and then output a reference voltage signal to the voltage comparison module 20 .

[0051] In this embodiment, the voltage divider module 12 is used to divide the first input voltage signal to obtain a reference voltage signal. For example, the voltage divider resistor can be set in the voltage divider module 12 to divide the first input voltage signal to obtain a reference voltage signal. In one embodiment, Figure 3 As shown, the voltage divider submodule 12 includes a fourth resistor R4 and a fifth resistor R5. The first end of the fourth resistor R4 is connected to the second end of the voltage comparison module 20, the second end of the fourth resistor R4 is connected to the first end of the voltage comparison module 20 and the first end of the fifth resistor R5, and the second end of the fifth resistor R5 is connected to ground. The fourth resistor R4 and the fifth resistor R5 also form a voltage divider circuit, which further divides the 5V voltage generated by the voltage stabilization submodule 11 to obtain a 2.5V reference voltage signal. The calculation formula is:

[0052]

[0053] The above is the specific working principle of the voltage divider submodule 12 .

[0054] On the basis of the above embodiment, the voltage comparison module 20 includes a first temperature-sensing resistor RT1, a sixth resistor R6, a first comparator U2 and a seventh resistor R7;

[0055] A first end of the first temperature-sensing resistor RT1 is connected to the third end of the voltage output module 10, a second end of the first temperature-sensing resistor RT1 is connected to the first end of the sixth resistor R6, the non-inverting input end of the first comparator U2, and the first end of the seventh resistor R7, and a second end of the sixth resistor R6 is grounded;

[0056] The inverting input terminal of the first comparator U2 is connected to the second terminal of the voltage output module 10 , and the output terminal of the first comparator U2 is connected to the second terminal of the seventh resistor R7 and the first terminal of the voltage regulating and adjusting module 30 .

[0057] In one embodiment, if Figure 3As shown, the voltage comparison module 20 includes a first temperature-sensing resistor RT1, a sixth resistor R6, a first comparator U2, and a seventh resistor R7. The first temperature-sensing resistor RT1 and the sixth resistor R6 form a voltage divider circuit. The first temperature-sensing resistor RT1 is a negative temperature coefficient resistor, that is, a resistor whose resistance decreases as the temperature increases. The voltage value VR6 divided by the sixth resistor R6 is also the voltage obtained at the non-inverting input terminal of the first comparator U2, and the calculation formula is:

[0058]

[0059] Therefore, in this embodiment, by appropriately selecting the resistance values ​​of the first temperature-sensing resistor RT1 and the sixth resistor R6, when the ambient temperature is 0°C, VR6 is lower than the 2.5V reference voltage at the inverting input of the first comparator U2, causing the first comparator U2 to output a low-level signal. When the ambient temperature exceeds 10°C, the resistance value of RT1 decreases, and VR6 increases, causing VR6 to exceed the 2.5V reference voltage at the inverting input of the first comparator U2, causing the first comparator U2 to output a high-level signal. Furthermore, the seventh resistor R7, which sets the input hysteresis voltage, is appropriately selected to maintain a relatively stable output state for the first comparator U2 when the temperature is around 10°C.

[0060] Based on the above embodiment, the voltage regulating and adjusting module 30 includes a first diode D2, an eighth resistor R8, a ninth resistor R9, a linear low voltage difference voltage regulating circuit U3, a tenth resistor R10, a second temperature sensing resistor RT2 and a first capacitor C1;

[0061] The negative electrode of the first diode D2 is connected to the third end of the voltage comparison module 20, the first end of the eighth resistor R8 is connected to the power supply 50 and the power supply end of the linear low voltage difference voltage regulator circuit U3, the second end of the eighth resistor R8 is connected to the ninth resistor R9, the enable end of the linear low voltage difference voltage regulator circuit U3 and the positive electrode of the first diode D2, the voltage adjustment end of the linear low voltage difference voltage regulator circuit U3 is connected to the first end of the second temperature sensing resistor RT2 and the second end of the tenth resistor R10, the first end of the tenth resistor R10 is connected to the output end of the linear low voltage difference voltage regulator circuit U3, the first end of the first capacitor C1 and the control end of the fan 40, the second end of the ninth resistor R9, the second end of the second temperature sensing resistor RT2 and the second end of the first capacitor C1 are all grounded.

[0062] In this embodiment, the voltage regulation module 30 includes a first diode D2, an eighth resistor R8, a ninth resistor R9, a linear low-voltage-dropout voltage regulator circuit U3, a tenth resistor R10, a second temperature-sensitive resistor RT2, and a first capacitor C1. The second temperature-sensitive resistor RT2 is a negative temperature coefficient resistor, and the linear low-voltage-dropout voltage regulator circuit U3 is a MIC29302BU chip. When the voltage comparison module 20 outputs a low-level signal, the clamping action of the first diode D2 causes the anode voltage of the first diode D2 to be clamped at 0.7V. This means that the voltage at the enable terminal (ENB) of the MIC29302BU chip is 0.7V, which is unable to reach the voltage threshold for enabling the MIC29302BU chip. The MIC29302BU chip maintains a no-voltage output state, meaning that there is no control signal at this time, and the fan 40 does not rotate. This prevents the fan 40 from burning out when it is activated after freezing at temperatures below 0°C.

[0063] When the voltage comparison module 20 outputs a high-level signal, due to the isolation effect of the first diode D2, the high-level signal cannot be applied to the enable terminal (ENB) of the MIC29302BU chip. However, the voltage at the enable terminal of the MIC29302BU chip is controlled by the eighth resistor R8 and the ninth resistor R9. By reasonably setting the resistance values ​​of the eighth resistor R8 and the ninth resistor R9 so that the voltage value of the ninth resistor R9 is higher than the turn-on threshold of the enable terminal (ENB) of the MIC29302BU chip, the MIC29302BU chip can output a control signal to the fan 40 to start the fan 40.

[0064] In addition, the tenth resistor R10 and the second temperature-sensing resistor RT2 form the feedback network of the output voltage of the MIC29302BU chip, and the first capacitor C1 is a filtering and energy storage capacitor. The relationship between the output voltage Uo of the output terminal of the MIC29302BU chip and the tenth resistor R10 and the second temperature-sensing resistor RT2 is as follows:

[0065]

[0066] Since the second temperature-sensing resistor RT2 is a negative temperature coefficient resistor, that is, the resistance value decreases as the temperature rises, the output voltage Uo of the MIC29302BU chip increases, and the speed of the fan 40 increases, thereby improving the cooling effect of the fan 40.

[0067] As described above, the present invention provides a cooling fan control circuit. This circuit prevents the fan from starting when the temperature is low, preventing the fan from burning out when the fan bearings freeze due to forced fan startup. This circuit addresses the prior art issue of fans burning out when starting at low temperatures. Furthermore, when the temperature is high, the present invention controls the fan to start and automatically adjusts its speed based on the temperature to ensure effective cooling, extend the fan's lifespan, and save energy.

[0068] The present invention also provides a cooling fan comprising the aforementioned cooling fan control circuit. This embodiment of the present invention prevents the fan from activating when the temperature is low, thus preventing the fan from burning out when the fan bearings freeze due to forced activation. This resolves the prior art technical issue of fans being easily burned out when activated at low temperatures. Furthermore, when the temperature is high, this embodiment of the present invention controls the fan to activate and automatically adjusts the fan speed based on the temperature to ensure effective cooling, extend the fan's operating life, and achieve energy savings.

[0069] The specific embodiments described above further illustrate the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A cooling fan control circuit, characterized in that: It includes a voltage output module, a voltage comparison module and a voltage regulation module; The first end of the voltage output module is connected to the power supply, the second end of the voltage output module is connected to the first end of the voltage comparison module, and is used to output a reference voltage signal to the voltage comparison module; the third end of the voltage output module is connected to the second end of the voltage comparison module, and is used to output a first input voltage signal to the voltage comparison module; The third terminal of the voltage comparison module is connected to the first terminal of the voltage stabilization adjustment module. The voltage comparison module is configured to convert the first input voltage signal into a second input voltage signal. When the reference voltage signal is greater than the second input voltage signal, the voltage comparison module outputs a low-level signal to the voltage stabilization adjustment module. When the reference voltage signal is less than the second input voltage signal, the voltage comparison module outputs a high-level signal to the voltage stabilization adjustment module. The voltage value of the second input voltage signal is positively correlated with the temperature value. The second end of the voltage stabilization adjustment module is connected to the power supply, and the third end of the voltage stabilization adjustment module is connected to the control end of the fan. The voltage stabilization adjustment module is used to not output the control signal to the control end of the fan when receiving the low-level signal; and to output the control signal to the fan in real time according to the temperature when receiving the high-level signal, and the control signal is used to control the speed of the fan.

2. The cooling fan control circuit according to claim 1, wherein: The voltage output module includes a voltage stabilizing submodule and a voltage dividing submodule; The first end of the voltage stabilizing submodule is connected to the power supply, and the second end of the voltage stabilizing submodule is connected to the first end of the voltage dividing submodule and the second end of the voltage comparison module. The voltage stabilizing submodule is configured to output a first input voltage signal with a constant voltage value to the voltage dividing submodule and the voltage comparison module after stabilizing the power supply voltage signal provided by the power supply; The second end of the voltage dividing submodule is used to be connected to the first end of the voltage comparison module. The voltage dividing submodule is used to divide the first input voltage signal and then output the reference voltage signal to the voltage comparison module.

3. The cooling fan control circuit according to claim 2, wherein: The voltage stabilizing submodule includes a first voltage stabilizing tube, a controllable precision voltage stabilizing source, a first resistor, a second resistor, a third resistor, a fourth resistor and a fifth resistor; The negative electrode of the first voltage-stabilizing diode is connected to the power supply, the positive electrode of the first voltage-stabilizing diode is connected to the first end of the first resistor, the second end of the first resistor is connected to the cathode of the controllable precision voltage-stabilizing source, the first end of the second resistor and the first end of the voltage divider module, the second end of the second resistor is connected to the reference level of the controllable precision voltage-stabilizing source and the first end of the third resistor; the anode of the controllable precision voltage-stabilizing source and the second end of the third resistor are grounded.

4. The cooling fan control circuit according to claim 2, wherein: The voltage divider module includes a fourth resistor and a fifth resistor, the first end of the fourth resistor is connected to the second end of the voltage comparison module, the second end of the fourth resistor is connected to the first end of the voltage comparison module and the first end of the fifth resistor, and the second end of the fifth resistor is grounded.

5. The cooling fan control circuit according to claim 1, wherein: The voltage comparison module includes a first temperature-sensing resistor, a sixth resistor, a first comparator and a seventh resistor; A first end of the first temperature-sensing resistor is connected to the third end of the voltage output module, a second end of the first temperature-sensing resistor is connected to the first end of the sixth resistor, the non-inverting input end of the first comparator, and the first end of the seventh resistor, and a second end of the sixth resistor is grounded; The inverting input terminal of the first comparator is connected to the second terminal of the voltage output module, and the output terminal of the first comparator is connected to the second terminal of the seventh resistor and the first terminal of the voltage regulating module.

6. The cooling fan control circuit according to claim 5, characterized in that: The first temperature-sensitive resistor is a negative temperature coefficient resistor.

7. The cooling fan control circuit according to claim 1, wherein: The voltage stabilization and adjustment module includes a first diode, an eighth resistor, a ninth resistor, a linear low voltage difference voltage stabilization circuit, a tenth resistor, a second temperature-sensitive resistor, and a first capacitor; The negative electrode of the first diode is connected to the third end of the voltage comparison module, the first end of the eighth resistor is connected to the power supply and the power supply end of the linear low voltage difference voltage regulator circuit, the second end of the eighth resistor is connected to the ninth resistor, the enable end of the linear low voltage difference voltage regulator circuit and the positive electrode of the first diode, the voltage regulation end of the linear low voltage difference voltage regulator circuit is connected to the first end of the second temperature-sensitive resistor and the second end of the tenth resistor, the first end of the tenth resistor is connected to the output end of the linear low voltage difference voltage regulator circuit, the first end of the first capacitor and the control end of the fan, the second end of the ninth resistor, the second end of the second temperature-sensitive resistor and the second end of the first capacitor are all grounded.

8. The cooling fan control circuit according to claim 7, wherein: The second temperature-sensitive resistor is a negative temperature coefficient resistor.

9. The cooling fan control circuit according to claim 7, wherein: The linear low voltage difference voltage stabilizing circuit is a MIC29302BU chip.

10. A cooling fan, characterized in that: The cooling fan control circuit comprises the cooling fan control circuit according to any one of claims 1 to 9.

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