Anti-interference signal processing circuit and fan

Abstract

The utility model discloses an anti-interference signal processing circuit and a fan, the circuit comprises an acquisition signal reverse connection protection unit, an acquisition signal input filtering unit, a comparator unit, a voltage dividing unit and a signal output filtering unit, the acquisition signal reverse connection protection unit is used for carrying out reverse voltage protection on an acquired PWM signal; the acquisition signal input filtering unit is used for carrying out filtering processing on the acquired PWM signals, the comparator unit is used for carrying out voltage comparison processing and output on the acquired PWM signals, the voltage dividing unit is used for adjusting comparison voltage of the comparator unit, and the signal output filtering unit is used for filtering the PWM signals output by the comparator unit. According to the utility model, false levels in the signals can be effectively identified and eliminated, the high and low level states of the output PWM signals are ensured to be clear and stable, the problems of unstable rotating speed and the like caused by abnormal PWM signals due to input signal noise and PCB noise are solved, and the rotating speed of the fan is ensured to be stable.

Description

An anti-interference signal processing circuit and a fan Technical Field

[0001] This utility model relates to the field of fan technology, and in particular to an anti-interference signal processing circuit and a fan. Background Technology

[0002] Most fan speed controls on the market currently use PWM direct input control signals. ICs have a certain range for recognizing high and low levels of PWM input. During application, signal interference may cause the fan to malfunction in recognizing the PWM signal and control it abnormally, resulting in speed fluctuations and affecting the cooling function during use. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide an anti-interference signal processing circuit and fan, which aims to solve the problem of unstable fan speed caused by interference signals in the initially acquired PWM speed control signal.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] On one hand, this utility model provides an anti-interference signal processing circuit, including a signal reverse connection protection unit, a signal input filtering unit, a comparator unit, a voltage divider unit, and a signal output filtering unit. The signal reverse connection protection unit is used to protect the acquired PWM signal from reverse voltage. The signal input filtering unit is used to filter the acquired PWM signal. The comparator unit is used to perform voltage comparison processing and output the acquired PWM signal. The voltage divider unit is used to adjust the comparison voltage of the comparator unit. The signal output filtering unit is used to filter the PWM signal output by the comparator unit.

[0006] Furthermore, the comparator unit includes a comparator, which includes a non-inverting input terminal, an inverting input terminal, and an output terminal. The inverting input terminal is used to receive the PWM signal filtered by the acquisition signal input filtering unit, and the non-inverting input terminal is used to receive the reference voltage provided by the voltage divider unit.

[0007] Furthermore, when the voltage at the inverting input terminal of the comparator is less than the voltage at the non-inverting input terminal of the comparator, the output terminal of the comparator outputs a low level; when the voltage at the inverting input terminal of the comparator is greater than the voltage at the non-inverting input terminal of the comparator, the output terminal of the comparator outputs a high level.

[0008] Furthermore, the comparator unit also includes a resistor R4, one end of which is connected to the power supply voltage, and the other end of which is connected to the output terminal of the comparator.

[0009] Furthermore, the voltage divider unit includes resistors R2 and R3 connected in series between the power supply voltage and ground. The intermediate node of resistors R2 and R3 is connected to the non-inverting input terminal of the comparator to provide a reference voltage for the comparator.

[0010] Furthermore, the reverse connection protection unit for the acquired signal includes a diode D1, the anode of which is connected to the input terminal of the PWM signal, and the cathode of which is connected to the input filtering unit for the acquired signal.

[0011] Furthermore, the signal acquisition input filtering unit includes a resistor R1 and a capacitor C1 connected in series. The capacitor C1 is grounded, one end of the resistor R1 is connected to the cathode of the diode D1, and the intermediate node of the resistor R1 and the capacitor C1 is connected to the inverting input terminal of the comparator.

[0012] Furthermore, the signal output filtering unit includes a resistor R5 and a capacitor C2. One end of the resistor R5 is connected to the output terminal of the comparator, and the other end of the resistor R5 is connected to one end of the capacitor C2 and the output terminal of the PWM signal. The other end of the capacitor C2 is grounded.

[0013] On the other hand, this utility model also provides a fan, including the aforementioned anti-interference signal processing circuit.

[0014] The beneficial effects of this utility model compared with the prior art are as follows: An anti-interference signal processing circuit includes a signal reverse connection protection unit, a signal input filtering unit, a comparator unit, a voltage divider unit, and a signal output filtering unit. The signal reverse connection protection unit is used to provide reverse voltage protection for the acquired PWM signal. The signal input filtering unit is used to filter the acquired PWM signal. The comparator unit is used to perform voltage comparison processing and output the acquired PWM signal. The voltage divider unit is used to adjust the comparison voltage of the comparator unit. The signal output filtering unit is used to filter the PWM signal output by the comparator unit. This utility model, through the coordinated operation of the voltage divider unit and the comparator unit, compares the fluctuating PWM signal with a stable reference voltage in real time using a provided reference voltage. This effectively identifies and eliminates false levels in the signal, ensuring that the high and low level states of the output PWM signal are clear and stable. This solves the problem of unstable fan speed caused by abnormal PWM signals due to input signal noise and PCB board noise, thereby ensuring stable fan speed.

[0015] The above description is only an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model, it can be implemented according to the contents of the specification. In order to make the above and other objectives, features and advantages of this utility model more obvious and easy to understand, the following are preferred embodiments, which are described in detail below. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 is a schematic diagram of an anti-interference signal processing circuit provided in a specific embodiment of the present invention;

[0018] Figure 2 is a circuit diagram of an anti-interference signal processing circuit provided in a specific embodiment of this utility model.

[0019] Figure Labels

[0020] 1. Reverse connection protection unit for acquired signals; 2. Input filtering unit for acquired signals; 3. Comparator unit; 4. Voltage divider unit; 5. Output filtering unit for signals. Detailed Implementation

[0021] The technical solution of this utility model will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0022] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0023] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0024] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0025] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0026] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0027] As shown in Figures 1 and 2, this embodiment of the present invention provides an anti-interference signal processing circuit, including a reverse connection protection unit 1 for the acquired signal, an input filtering unit 2 for the acquired signal, a comparator unit 3, a voltage divider unit 4, and a signal output filtering unit 5. The reverse connection protection unit 1 is used to protect the acquired PWM signal from reverse voltage. The input filtering unit 2 is used to filter the acquired PWM signal. The comparator unit 3 is used to perform voltage comparison processing and output the acquired PWM signal. The voltage divider unit 4 is used to adjust the comparison voltage of the comparator unit 3. The signal output filtering unit 5 is used to filter the PWM signal output by the comparator unit 3.

[0028] The reverse connection protection unit 1 for acquiring signals is used to protect the acquired PWM signal from reverse voltage. Specifically, it includes diode D1. In the actual circuit connection, the anode of diode D1 is connected to the input terminal of the PWM signal, and the cathode of diode D1 is connected to the acquisition signal input filter unit 2. Its working principle utilizes the unidirectional conductivity of the diode. When the PWM signal is normally connected, current flows from the anode to the cathode of diode D1, the diode conducts, and the PWM signal can smoothly pass through to the subsequent circuit. If the PWM signal is reversed, the cathode potential of the diode is higher than the anode potential, the diode is cut off, preventing reverse current from flowing, thus protecting the subsequent circuit components from damage by reverse voltage. For example, in a fan control system, the PWM signal is used to control the fan speed. If the PWM signal input line is reversed during installation or use, diode D1 can effectively prevent damage to the entire signal processing circuit caused by reverse voltage.

[0029] The signal input filtering unit 2 is used to filter the acquired PWM signal. It includes a resistor R1 and a capacitor C1 connected in series. Capacitor C1 is grounded, one end of resistor R1 is connected to the cathode of diode D1, and the midpoint between resistor R1 and capacitor C1 is connected to the inverting input of the comparator. This signal input filtering unit 2 constitutes an RC low-pass filter circuit. Its working principle is as follows: when the PWM signal is input, because capacitor C1 has low capacitive reactance for high-frequency signals, high-frequency interference signals can more easily flow to ground through capacitor C1, while low-frequency PWM signals can smoothly reach the inverting input of the comparator through resistor R1. For example, assuming the PWM signal frequency is 100Hz, and there is a 10kHz high-frequency interference signal in the circuit, the 10kHz high-frequency interference signal will be significantly attenuated by this RC low-pass filter circuit, while the 100Hz PWM signal can be transmitted to the subsequent circuit with almost no loss, thereby effectively filtering out high-frequency interference in the PWM signal and improving signal quality.

[0030] Voltage divider unit 4 is used to adjust the comparison voltage of comparator unit 3. Specifically, it includes resistors R2 and R3 connected in series between the power supply voltage and ground. The midpoint of resistors R2 and R3 is connected to the non-inverting input of the comparator to provide a reference voltage. According to the principle of resistor voltage divider, the reference voltage is the power supply voltage. For example, when the power supply voltage is 5V, resistor R2 is 10kΩ, and resistor R3 is 10kΩ, the reference voltage Vref = 5 × 10 + 1010 = 2.5V. By adjusting the resistance ratio of resistors R2 and R3, the reference voltage value provided to the non-inverting input of the comparator can be flexibly changed to adapt to different PWM signal processing requirements. For example, in different application scenarios, the amplitude range of the PWM signal may be different. By adjusting the resistance values ​​of the voltage divider resistors, the reference voltage of the comparator can be matched to this range, thereby achieving accurate voltage comparison.

[0031] Comparator unit 3 is used to perform voltage comparison processing and output of the acquired PWM signal. This unit includes a comparator and resistor R4. The comparator includes a non-inverting input, an inverting input, and an output. The inverting input receives the PWM signal filtered by the acquisition signal input filtering unit 2, and the non-inverting input receives the reference voltage provided by the voltage divider unit 4. When the voltage at the inverting input of the comparator is less than the voltage at the non-inverting input, the comparator outputs a low level; when the voltage at the inverting input is greater than the voltage at the non-inverting input, the comparator outputs a high level. One end of resistor R4 is connected to the power supply voltage, and the other end is connected to the output of the comparator. Resistor R4 acts as a pull-up resistor. For some comparators with open collector (OC) or open drain (OD) output structures, they cannot directly output a high level and need to be connected to the power supply externally. After connecting R4, when the comparator outputs a high level, the power supply voltage is obtained through R4 to achieve a high-level output; when the output is low, the current flows to the comparator output through R4. For example, in a certain type of comparator chip, this connection method can ensure that the comparator outputs stable high and low level signals, thereby accurately processing the PWM signal.

[0032] The signal output filtering unit 5 is used to filter the PWM signal output by the comparator unit 3. This unit includes a resistor R5 and a capacitor C2. One end of the resistor R5 is connected to the output terminal of the comparator, and the other end of the resistor R5 is connected to one end of the capacitor C2 and the output terminal of the PWM signal. The other end of the capacitor C2 is grounded. This also constitutes an RC low-pass filter circuit. When the PWM signal output by the comparator passes through the resistor R5, any high-frequency interference signals that may exist in it flow to ground through the capacitor C2, while the low-frequency PWM signal is output to the output terminal of the PWM signal. For example, even after the previous processing, if there is still a small amount of high-frequency noise in the PWM signal output by the comparator, the signal output filtering unit 5 can further filter out this noise, making the final output PWM signal purer and more stable, meeting the signal stability requirements of subsequent applications.

[0033] This embodiment of the invention also provides a fan, including the aforementioned anti-interference signal processing circuit. Apart from the anti-interference signal processing circuit, the remaining structure of the fan is the same as that in the prior art, and will not be described in detail here.

[0034] It should be noted that the fan provided by this utility model includes the above-mentioned anti-interference signal processing circuit, and therefore has all the beneficial effects of the anti-interference signal processing circuit, which will not be repeated here.

[0035] In summary, this invention, through the coordinated operation of the voltage divider unit 4 and the comparator unit 3, compares the fluctuating PWM signal with the stable reference voltage in real time using the provided reference voltage. This effectively identifies and eliminates false levels in the signal, ensuring that the high and low level states of the output PWM signal are clear and stable. It solves the problem of unstable fan speed caused by abnormal PWM signals due to input signal noise and PCB board noise, thereby ensuring stable fan speed.

[0036] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this utility model, and these modifications or substitutions should all be covered within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope of the claims.

Claims

1. An interference-immune signal processing circuit, characterized by comprising: The system includes a reverse connection protection unit for the acquired signal, an input filtering unit for the acquired signal, a comparator unit, a voltage divider unit, and a signal output filtering unit. The reverse connection protection unit for the acquired signal is used to provide reverse voltage protection for the acquired PWM signal. The input filtering unit for the acquired signal is used to filter the acquired PWM signal. The comparator unit for the acquired PWM signal is used to perform voltage comparison processing and output. The voltage divider unit for the acquired signal is used to adjust the comparison voltage of the comparator unit. The signal output filtering unit for the acquired signal is used to filter the PWM signal output by the comparator unit.

2. The anti-jamming signal processing circuit according to claim 1, characterized in that, The comparator unit includes a comparator, which includes a non-inverting input, an inverting input, and an output. The inverting input is used to receive the PWM signal after being filtered by the acquisition signal input filtering unit, and the non-inverting input is used to receive the reference voltage provided by the voltage divider unit.

3. The interference-immune signal processing circuit according to claim 2, wherein When the voltage at the inverting input terminal of the comparator is less than the voltage at the non-inverting input terminal of the comparator, the output terminal of the comparator outputs a low level; when the voltage at the inverting input terminal of the comparator is greater than the voltage at the non-inverting input terminal of the comparator, the output terminal of the comparator outputs a high level.

4. The anti-jamming signal processing circuit of claim 2, wherein, The comparator unit also includes a resistor R4, one end of which is connected to the power supply voltage, and the other end of which is connected to the output terminal of the comparator.

5. The tamper-resistant signal processing circuit of claim 2, wherein, The voltage divider unit includes resistors R2 and R3 connected in series between the power supply voltage and ground. The midpoint between resistors R2 and R3 is connected to the non-inverting input of the comparator to provide a reference voltage for the comparator.

6. The anti-jamming signal processing circuit of claim 2, wherein, The reverse connection protection unit for the acquired signal includes a diode D1, the anode of which is connected to the input terminal of the PWM signal, and the cathode of which is connected to the input filtering unit for the acquired signal.

7. An interference-immune signal processing circuit according to claim 6, characterized in that, The signal input filtering unit includes a resistor R1 and a capacitor C1 connected in series. The capacitor C1 is grounded, one end of the resistor R1 is connected to the cathode of the diode D1, and the middle node of the resistor R1 and the capacitor C1 is connected to the inverting input terminal of the comparator.

8. The anti-jamming signal processing circuit of claim 2, wherein, The signal output filtering unit includes a resistor R5 and a capacitor C2. One end of the resistor R5 is connected to the output terminal of the comparator, and the other end of the resistor R5 is connected to one end of the capacitor C2 and the output terminal of the PWM signal. The other end of the capacitor C2 is grounded.

9. A fan, characterized by The signal processing circuit includes the anti-interference circuit described in any one of claims 1-8.

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