Direct-current fan speed regulating device

By combining signal isolation, chopper output and filtering circuits with temperature detection circuits, the anti-interference and stability problems of DC fan speed control devices are solved, achieving precise speed control and noise reduction.

CN224032812UActive Publication Date: 2026-03-24HAIER HAISI XIAN CONTROL TECH CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Utility models(China)
Current Assignee / Owner
Filing Date
2025-05-09
Publication Date
2026-03-24

AI Technical Summary

Technical Problem

Existing DC fan speed control devices have weak anti-interference capabilities, poor stability, and high noise levels, making it difficult to achieve precise speed regulation.

Method used

It employs a signal isolation circuit, a chopper output circuit, an LC filter circuit, and a temperature detection circuit. It utilizes optocoupler isolation for speed control signals, insulated gate bipolar transistors for chopper output, and LC filtering to reduce noise. Combined with a thermistor to monitor temperature and adjust the speed in real time.

Benefits of technology

It improves the circuit's anti-interference capability, enhances stability, reduces noise, and achieves precise speed control of the DC fan.

✦ Generated by Eureka AI based on patent content.

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Abstract

The utility model discloses a direct-current fan speed regulation device which comprises a signal isolation circuit, an input end of which is connected with an external control signal and is used for opto-coupler isolation of a speed regulation control signal. And the chopping output circuit is respectively connected with the output end of the signal isolation circuit and the external power supply and is used for chopping the external power supply. And the LC filter circuit is respectively connected with the chopping output circuit and an external power supply and is used for outputting direct-current voltage through filtering. And the temperature detection circuit is connected with the + 3.3 V power supply and the direct current fan, and monitors the temperature of a heat dissipation part of the fan through a thermistor and a resistor. And the speed regulation control signal is subjected to optical coupling isolation, so that interference of an external power supply VCC is avoided, and the anti-interference capability of the circuit is improved. The chopping output circuit is more suitable for high-voltage and large-current occasions, and the stability is improved. And the direct-current fan is driven after filtering, so that the noise of the direct-current fan can be obviously reduced. The rotating speed of the direct-current fan is adjusted by adjusting the speed adjusting control signal in real time, and the purpose of accurately controlling the temperature is achieved.
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Description

TECHNICAL FIELD

[0001] The utility model relates to direct current fan speed regulation control technical field especially relates to a direct current fan speed regulation device. BACKGROUND

[0002] Direct current fan is a kind of electric appliance for heat dissipation, and is widely applied in industrial or electronic equipment field.In many industries and electronic equipment, the temperature of equipment needs to be accurately controlled to ensure the performance and life of equipment.

[0003] As the important execution element of temperature control, the rotating speed of direct current fan needs to be accurately regulated according to the temperature variation of equipment.The speed regulation of existing direct current fan generally adopts PWM (i.e.pulse width modulation) chopping voltage regulation to achieve the purpose of speed regulation.However, the direct current fan speed regulation device generally adopts field effect tube as power device, so that the existing direct current fan speed regulation device has the technical problems of weak anti-interference ability, poor stability and large noise. CONTENT OF UTILITY MODEL

[0004] In order to solve the above technical problems, the utility model provides a kind of direct current fan speed regulation device, the rotating speed of direct current fan is adjusted by signal isolation circuit, chopping output circuit, LC filter circuit and temperature detection circuit.

[0005] In order to achieve the above purpose, the utility model is realized by the following technical schemes:

[0006] A kind of direct current fan speed regulation device, comprising:

[0007] Signal isolation circuit, its input end is connected with external control signal, for photocoupler isolation speed regulation control signal;

[0008] Chopping output circuit is connected with the output end of signal isolation circuit, external power respectively, for chopping to external power;

[0009] LC filter circuit is connected with chopping output circuit, external power respectively, for filtering output direct current voltage;

[0010] Temperature detection circuit is connected with +3.3V power supply, direct current fan, the temperature of fan heat dissipation component is monitored by thermistor and resistance.

[0011] Compared with prior art, the utility model has the following advantages:

[0012] The speed control signal is optically coupled to avoid the interference of the external power supply VCC, and the anti-interference ability of the circuit is improved. The chopper output circuit uses an insulated gate bipolar transistor as a power device, which is more suitable for high-voltage and large-current occasions, and the stability is improved. The noise of the DC fan can be obviously reduced after the chopper output is filtered to drive the DC fan. Finally, the temperature of the heat dissipation component is monitored by using a thermistor, and the speed of the DC fan is adjusted in real time by adjusting the speed control signal to realize the purpose of accurate temperature control.

[0013] Further preferably, the signal isolation circuit comprises:

[0014] A first resistor, one end of which is connected with an external control signal.

[0015] An optocoupler, a third pin of which is connected with the other end of the first resistor, and a second resistor and a first capacitor are arranged between the third pin and a second pin of the optocoupler, the second resistor and the first capacitor are connected in parallel, one end of the parallel connection is connected with a power supply +3.3V, and the other end of the parallel connection is connected with the third pin of the optocoupler; a first pin and a fourth pin of the optocoupler are connected with a ground GND, the second pin is connected with the power supply +3.3V, a fifth pin is connected with a ground COM, and an eighth pin is connected with an external power supply.

[0016] By adopting the above technical solution, the signal isolation circuit composed of the first resistor, the second resistor, the first capacitor and the optocoupler optically couples the speed control signal to avoid the interference of the external power supply on the speed control signal, and the anti-interference ability of the power supply is improved.

[0017] Further preferably, the chopper output circuit comprises:

[0018] A third resistor, an insulated gate bipolar transistor, a fourth resistor, a transient suppression diode, a second capacitor, a fifth resistor and a diode, one end of the third resistor is connected with a sixth pin and a seventh pin of the optocoupler respectively, and the other end is connected with a first pin of the insulated gate bipolar transistor.

[0019] The fourth resistor, the transient suppression diode and the first capacitor are connected in parallel, one end of the parallel connection is connected with a first pin of the insulated gate bipolar transistor, and the other end is connected with a third pin of the insulated gate bipolar transistor.

[0020] The fifth resistor and the diode are connected in parallel, one end of the parallel connection is connected with an external power supply, and the other end is connected with a second pin of the insulated gate bipolar transistor.

[0021] By adopting the above technical solution, the chopper output circuit composed of the third resistor, the fourth resistor, the fifth resistor, the second capacitor, the transient suppression diode, the diode and the insulated gate bipolar transistor chops the external power supply through the insulated gate bipolar transistor, and the anti-interference ability of the circuit is improved.

[0022] Further preferably, the LC filter circuit comprises:

[0023] an inductor, one end of which is connected to the external power supply VCC and the other end of which is connected to the output signal FAN1_L;

[0024] a third capacitor, the positive electrode of which is connected to the output signal FAN1_L and the negative electrode of which is connected to the second pin of the insulated gate bipolar transistor and the output signal FAN1_N respectively.

[0025] By the above technical solution, the LC filter circuit composed of the inductor L1 and the third capacitor is used to filter the chopping and drive the DC fan, thereby reducing the noise.

[0026] Further preferably, the temperature detection circuit comprises a sixth resistor and a thermistor, one end of the sixth resistor is connected to the power supply +3.3V and the other end of the sixth resistor is connected to the ground GND through the thermistor, and the connection point of the sixth resistor and the thermistor is connected to the output signal NTC_OUT.

[0027] By the above technical solution, the thermistor is used to detect the temperature of the heat dissipation component of the DC fan, thereby providing a temperature basis for adjusting the speed control signal to control the speed of the DC fan in real time.

[0028] Further preferably, the optocoupler is of the TLP250 type.

[0029] By the above technical solution, the optocoupler of this type can quickly respond to signal changes and has the effect of preventing interference, improving circuit stability and reliability.

[0030] Further preferably, the insulated gate bipolar transistor is of the AOD482 type.

[0031] By the above technical solution, the insulated gate bipolar transistor of this type has the characteristics of high voltage and large current processing capability and low driving power, so that the circuit is suitable for high voltage and large current application occasions. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 The figure is a circuit schematic diagram of the embodiment.

[0033] Figure 2 The figure is a schematic diagram of the temperature detection circuit in the embodiment.

[0034] Signs: 1 - signal isolation circuit; R1 - first resistance; R2 - second resistance; C1 - first capacitor; OP1 - optical coupling; 2 - chopper output circuit; R3 - third resistance; R4 - fourth resistance; R5 - fifth resistance; C1 - second capacitor; D1 - transient suppression diode; D2 - diode; Q1 - insulated gate bipolar transistor; 3 - LC filter circuit; L1 - inductor; C3 - third capacitor; 4 - temperature detection circuit; R6 - sixth resistance; NTC1 - thermistor; MCU_PWM - external control signal; VCC - external power supply. DETAILED DESCRIPTION

[0035] The following will be described in detail below Figures 1-2 The utility model is further described in detail.

[0036] A DC fan speed regulating device, as shown in the figure, comprises: Figure 1 Signal isolation circuit 1, the input end thereof is connected with external control signal MCU_PWM, and is used for optical coupling OP1 isolation of speed regulating control signal.

[0037] Chopper output circuit 2 is connected with the output end of signal isolation circuit 1 and external power supply VCC respectively, and is used for chopping external power supply VCC.

[0038] LC filter circuit 3 is connected with chopper output circuit 2 and external power supply VCC respectively, and is used for filtering output DC voltage.

[0039] Temperature detection circuit 4 is connected with +3.3V power supply and DC fan, and the temperature of fan heat dissipation component is monitored through thermistor NTC1 and resistance.

[0040] Speed regulating control signal is isolated through optical coupling OP1, the interference of external power supply VCCVCC is avoided, and the anti-interference ability of the circuit is improved.

[0041] Specifically, as shown in the figure, signal isolation circuit 1 in the embodiment comprises: Figure 1

[0042] First resistance R1, one end of which is connected with external control signal MCU_PWM.

[0043] ​The third pin of the optical coupler OP1 is connected with the other end of the first resistor R1, the second resistor R2 and the first capacitor C1 are arranged between the third pin and the second pin of the optical coupler OP1, the second resistor R2 is connected with the first capacitor C1 in parallel, one end of the parallel connection is connected with the power supply +3.3V, and the other end of the parallel connection is connected with the third pin of the optical coupler OP1; the first pin and the fourth pin of the optical coupler OP1 are connected with the ground GND, the second pin is connected with the power supply +3.3V, the fifth pin is connected with the ground COM, and the eighth pin is connected with the external power supply VCC.

[0044] The signal isolation circuit 1 composed of the first resistor R1, the second resistor R2, the first capacitor C1 and the optical coupler OP1 performs optical coupling OP1 isolation on the speed control signal, avoids the interference of the external power supply VCC on the speed control signal, and improves the anti-interference ability of the power supply.

[0045] Specifically, as shown in the figure, Figure 1 As shown in the figure, the chopper output circuit 2 in the embodiment includes:

[0046] The third resistor R3, the insulated gate bipolar transistor Q1, the fourth resistor R4, the transient suppression diode D2D1, the second capacitor C2, the fifth resistor R5 and the diode D2, one end of the third resistor R3 is connected with the sixth pin and the seventh pin of the optical coupler OP1, and the other end is connected with the first pin of the insulated gate bipolar transistor Q1;

[0047] The fourth resistor R4, the transient suppression diode D2D1 and the first capacitor C1 are connected in parallel, one end of the parallel connection is connected with the first pin of the insulated gate bipolar transistor Q1, and the other end is connected with the third pin of the insulated gate bipolar transistor Q1;

[0048] The fifth resistor R5 and the diode D2 are connected in parallel, one end of the parallel connection is connected with the external power supply VCC, and the other end is connected with the second pin of the insulated gate bipolar transistor Q1.

[0049] The chopper output circuit 2 composed of the third resistor R3, the fourth resistor R4, the fifth resistor R5, the second capacitor C2, the transient suppression diode D2D1, the diode D2 and the insulated gate bipolar transistor Q1 chops the external power supply VCC through the insulated gate bipolar transistor Q1, thereby improving the anti-interference ability of the circuit.

[0050] Specifically, as shown in the figure, Figure 1 As shown in the figure, the LC filter circuit 3 in the embodiment includes:

[0051] The inductor L1 has one end connected with the external power supply VCCVCC and the other end connected with the output signal FAN1_L;

[0052] A third capacitor C3 has a positive pole connected to the output signal FAN1_L and a negative pole connected to the second pin of the insulated gate bipolar transistor Q1 and the output signal FAN1_N.

[0053] The LC filter circuit 3 composed of the inductor L1 and the third capacitor C3 filters the chopping and drives the DC fan, thereby reducing the noise.

[0054] Specifically, as shown in Figure 2 In the embodiment, the temperature detection circuit 4 includes a sixth resistor R6 and a thermistor NTC1. One end of the sixth resistor R6 is connected to the power supply +3.3V, and the other end is connected to the ground GND through the thermistor NTC1. The connection point of the sixth resistor R6 and the thermistor NTC1 is connected to the output signal NTC_OUT.

[0055] The thermistor NTC1 detects the temperature of the heat dissipation component of the DC fan, thereby providing a temperature basis for controlling the speed of the DC fan in real time by adjusting the speed control signal.

[0056] Specifically, as shown in Figure 1 In the embodiment, the optocoupler OP1 is of the TLP250 type. The optocoupler OP1 of this type can quickly respond to signal changes and has the functions of preventing interference and improving the stability and reliability of the circuit.

[0057] Specifically, as shown in Figure 1 In the embodiment, the insulated gate bipolar transistor Q1 is of the AOD482 type. The insulated gate bipolar transistor Q1 of this type has the characteristics of high voltage and large current processing capability and low driving power, so that the circuit is suitable for high voltage and large current application occasions.

[0058] Please refer to Figure 1 and Figure 2 The working principle of the embodiment is as follows: the speed control signal is isolated by the signal isolation circuit 1, the external power supply VCC is chopped by the driving insulated gate bipolar transistor Q1, the chopped output is filtered by the LCLC filter circuit 3, the required DC voltage is obtained, and the DC voltage drives the DC fan to work. The size of the output voltage is adjusted by changing the duty cycle of the control signal, so as to achieve the purpose of speed regulation of the DC fan.

[0059] In summary, the circuit has the characteristics of simple structure and strong anti-interference ability, and can achieve the purposes of precise speed control and noise reduction.

[0060] This specific embodiment is only an explanation of the utility model, and is not a limitation of the utility model. Those skilled in the art can make modifications to the embodiment without creative contribution after reading the specification, but as long as it is within the protection scope of the utility model, it is protected by the patent law.

Claims

1. A DC fan speed regulating device, characterized by, The application relates to a signal isolation circuit, which comprises the following parts: a signal isolation circuit (1) connected with an external control signal (MCU_PWM) for optically coupling and isolating a speed control signal; a chopper output circuit (2) connected with the output end of the signal isolation circuit (1) and an external power supply for chopping the external power supply; an LC filter circuit (3) connected with the chopper output circuit (2) and an external power supply (VCC) for filtering and outputting a direct current voltage; a temperature detection circuit (4) connected with a +3.3V power supply and a direct current fan for monitoring the temperature of a fan heat dissipation component through a thermistor and a resistor.

2. The DC fan speed regulation device of claim 1, wherein The signal isolation circuit (1) comprises: a first resistor (R1) with one end connected with the external control signal (MCU_PWM); an optocoupler (OP1) with the other end of the first resistor (R1) connected with the third pin, the second resistor (R2) and the first capacitor (C1) arranged between the third pin and the second pin, the second resistor (R2) and the first capacitor (C1) being connected in parallel, one end of the parallel connection being connected with the power supply +3.3V, the other end of the parallel connection being connected with the third pin of the optocoupler (OP1), the first pin and the fourth pin of the optocoupler (OP1) being connected with the ground GND, the second pin being connected with the power supply +3.3V, the fifth pin being connected with the ground COM, and the eighth pin being connected with the external power supply (VCC).

3. The DC fan speed regulation device of claim 2, wherein The chopper output circuit (2) comprises: a third resistor (R3), an insulated gate bipolar transistor (Q1), a fourth resistor (R4), a transient voltage suppressor (D1), a second capacitor (C2), a fifth resistor (R5) and a diode (D2), one end of the third resistor (R3) being connected with the sixth pin and the seventh pin of the optocoupler (OP1), the other end being connected with the first pin of the insulated gate bipolar transistor (Q1); the fourth resistor (R4), the transient voltage suppressor (D1) and the first capacitor (C1) being connected in parallel, one end of the parallel connection being connected with the first pin of the insulated gate bipolar transistor (Q1), the other end being connected with the third pin of the insulated gate bipolar transistor (Q1); the fifth resistor (R5) and the diode (D2) being connected in parallel, one end of the parallel connection being connected with the external power supply (VCC), the other end being connected with the second pin of the insulated gate bipolar transistor (Q1).

4. The device according to claim 3, wherein The LC filter circuit (3) comprises: an inductor (L1) with one end connected with the external power supply (VCC) and the other end connected with an output signal FAN1_L; a third capacitor (C3) with the positive pole connected with the output signal FAN1_L, the negative pole connected with the second pin of the insulated gate bipolar transistor (Q1) and an output signal FAN1_N.

5. The device according to claim 2, wherein The temperature detection circuit (4) comprises a sixth resistor (R6) and a thermistor (NTC1), one end of the sixth resistor (R6) being connected with the power supply +3.3V, the other end being connected with the ground GND through the thermistor (NTC1); the connection point of the sixth resistor (R6) and the thermistor (NTC1) being connected with an output signal NTC_OUT.

6. The device of claim 2 wherein the DC fan speed control is further characterized by: The optical coupler (OP1) is selected from TLP250 type.

7. The device according to claim 3, wherein The insulated gate bipolar transistor (Q1) is selected from AOD482 type.