Direct-current voltage and speed regulating circuit of one-way fan

Abstract

The utility model relates to the technical field of power supply voltage regulation circuits, and provides a one-way fan direct-current voltage regulation and speed regulation circuit which comprises a direct-current voltage reduction circuit connected with a PWM / DAC weight regulation circuit used for controlling the speed of a direct-current fan. And the step-down chip U1 is arranged in the direct-current step-down circuit and is used for realizing a step-down function in the direct-current step-down circuit. According to the circuit, a direct-current voltage reduction and speed regulation control strategy is optimized, continuity and stability of output voltage are ensured, the common voltage jitter problem in a traditional scheme is avoided, the circuit design effectively suppresses reverse electromotive force, the reliability and safety of a system are improved, meanwhile, the scheme improves the power conversion efficiency, heat is reduced, and the service life of the system is prolonged. The speed regulation control mode is simplified, smooth fan speed regulation is achieved, and the user experience and the energy utilization efficiency are remarkably improved.

Description

Technical Field

[0001] This utility model relates to the field of power supply voltage regulation circuit technology, specifically a unidirectional fan DC voltage regulation and speed control circuit. Background Technology

[0002] Since the application of unidirectional DC fans, with the continuous development of electronic devices and mechanical systems, the demand for heat dissipation solutions has also been growing. DC fans are widely used in various electrical devices due to their advantages such as high efficiency, low noise, and long lifespan. However, with product upgrades and technological advancements, users have increasingly higher performance requirements for DC fans, especially for speed control functions. Traditional DC fans usually operate at a fixed speed. Although this method is simple, it cannot adapt to different environmental conditions and load requirements, resulting in energy waste and a poor user experience.

[0003] Most existing DC fan speed control systems rely on fixed-frequency PWM signals or analog voltages for speed regulation. Such control systems have some limitations. On the one hand, due to the lack of effective voltage reduction and regulation mechanisms, the fan speed may become unstable when the input voltage fluctuates, affecting the heat dissipation effect and noise level. On the other hand, traditional designs often do not adequately consider overvoltage protection, which may cause damage to circuit components when faced with abnormal operating conditions. Utility Model Content

[0004] The present invention aims to address the shortcomings of the prior art by providing a unidirectional fan DC voltage regulation and speed control circuit, which can achieve continuous output without pressing the button, while reducing voltage fluctuations at both ends and preventing potential hazards such as fan vibration and reverse electromotive force.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a unidirectional fan DC voltage regulation and speed control circuit, comprising: a DC step-down circuit, wherein the DC step-down circuit is connected to a PWM / DAC weighting circuit, the PWM / DAC weighting circuit being used to control the speed of the DC fan; and a step-down chip U1, wherein the step-down chip U1 is disposed in the DC step-down circuit and is used to implement the step-down function in the DC step-down circuit.

[0006] Furthermore, the DC buck circuit includes input filter capacitors C1 and C5, a buck power inductor L1, and energy storage capacitors C2 and C3. The input filter capacitors C1 and C5 are connected in parallel between the input terminal VIN and ground to filter out high-frequency noise in the input power supply. The fourth pin of the buck chip U1 is connected to the input filter capacitors C1 and C5. The second pin of the buck chip U1 is connected to ground through resistors R1 and R3 to control the chip's on / off state. The second pin of the buck chip U1 is connected to resistor R2 for frequency setting. The first pin of the buck chip U1 is connected to a feedback network, which consists of resistors R4, R5A, and R5B. The fifth and sixth pins of the buck chip U1 are both connected to the buck power inductor L1. The other end of the buck power inductor L1 is connected to the energy storage capacitors C2 and C3. The energy storage capacitors C2 and C3 are connected in parallel between the output terminal OUT and ground to smooth the output voltage, and the output terminal OUT is connected to the load.

[0007] Furthermore, the PWM / DAC weighting circuit includes a unidirectional diode D1, a damping resistor R7, a PWM signal source, energy storage capacitors C7 and C8, and a resistor R8; one end of the unidirectional diode D1 is connected to the PWM signal source, and the other end is connected to the resistor R7; the resistor R7 is connected to the energy storage capacitors C7 and C8, and the energy storage capacitors C7 and C8 are connected to the resistor R8; the resistor R8 is connected to the feedback network, and the resistor R8 is connected to the first pin of the buck chip U1 through the feedback network to form a feedback loop.

[0008] Furthermore, the PWM signal source can be connected to an AD voltage converter to enable the input of analog and digital speed control signals.

[0009] Furthermore, the resistors R1 and R3 form an overvoltage protection structure, which can limit the current and prevent damage to the step-down chip U1.

[0010] Furthermore, the PWM / DAC weighting circuit is also equipped with a single-phase diode D1 to prevent current from flowing into the circuit in reverse and to protect the circuit from the influence of reverse voltage.

[0011] The advantages of this invention lie in its optimized DC-DC step-down and speed control strategy, ensuring the continuity and stability of the output voltage and avoiding the voltage jitter problem common in traditional solutions. The circuit design effectively suppresses back electromotive force, improving system reliability and safety. Simultaneously, this solution improves power conversion efficiency, reduces heat generation, simplifies speed control, achieves smooth fan speed adjustment, and significantly improves user experience and energy efficiency. Attached Figure Description

[0012] Figure 1This is a circuit diagram of the present invention.

[0013] Figure 1 In the middle: 1-DC step-down circuit; 2-PWM / DAC weighting circuit. Detailed Implementation

[0014] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0015] The following disclosure provides many different embodiments or examples for implementing different structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, various specific examples of processes and materials are provided in this application, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0016] This application provides a unidirectional fan DC voltage regulation and speed control circuit. This circuit optimizes the DC step-down and speed control strategies, ensuring the continuity and stability of the output voltage and avoiding the voltage jitter problem common in traditional solutions. The circuit design effectively suppresses back electromotive force, improving system reliability and safety. Simultaneously, this solution improves power conversion efficiency, reduces heat generation, simplifies speed control, and achieves smooth fan speed adjustment, significantly improving user experience and energy efficiency. The following provides a detailed description of this unidirectional fan DC voltage regulation and speed control circuit. It should be noted that the order of description of the following embodiments is not intended to limit the preferred order of embodiments.

[0017] The present application will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0018] Please see Figure 1 In this embodiment, a unidirectional fan DC voltage regulation and speed control circuit is provided, including: a DC step-down circuit 1, the DC step-down circuit 1 is connected to a PWM / DAC weighting circuit 2, the PWM / DAC weighting circuit 2 is used to control the speed of the DC fan; and a step-down chip U1, the step-down chip U1 is disposed in the DC step-down circuit 1, and is used to realize the step-down function in the DC step-down circuit 1.

[0019] During use, the DC step-down circuit 1 receives the input DC voltage and reduces it to a level suitable for driving the DC fan. At the same time, the PWM / DAC weighting circuit 2 is connected to the DC step-down circuit 1 to adjust the speed of the DC fan through PWM or DAC signals.

[0020] Furthermore, the DC buck circuit 1 includes input filter capacitors C1 and C5, a buck power inductor L1, and energy storage capacitors C2 and C3. The input filter capacitors C1 and C5 are connected in parallel between the input terminal VIN and ground to filter out high-frequency noise in the input power supply. The fourth pin of the buck chip U1 is connected to the input filter capacitors C1 and C5, and the second pin of the buck chip is connected to ground through resistors R1 and R3 to control the chip's on / off state. The second pin of the buck chip U1 is connected to resistor R2 for frequency setting. The first pin of the buck chip U1 is connected to the feedback network, which consists of resistors R4, R5A, and R5B. The fifth and sixth pins of the buck chip U1 are both connected to the buck power inductor L1. The other end of the buck power inductor L1 is connected to the energy storage capacitors C2 and C3. The energy storage capacitors C2 and C3 are connected in parallel between the output terminal OUT and ground to smooth the output voltage, and the output terminal OUT is connected to the load.

[0021] During operation, input filter capacitors C1 and C5, connected in parallel between the input terminal VIN and ground, are used to filter out high-frequency noise in the input power supply. The buck power inductor L1, together with energy storage capacitors C2 and C3, forms a stable output voltage system. Specifically, the fourth pin of the buck chip U1 is connected to the input filter capacitors C1 and C5 to receive the purified input voltage; the second pin is grounded through resistors R1 and R3 to control the chip's on / off state; the second pin is also connected to resistor R2 to set the operating frequency; the first pin is connected to the feedback network, which consists of resistors R4, R5A, and R5B, to regulate the output voltage; the fifth and sixth pins are both connected to the buck power inductor L1, and the other end of inductor L1 is connected to energy storage capacitors C2 and C3. These energy storage capacitors are connected in parallel between the output terminal OUT and ground, smoothing the final output voltage supplied to the load. This scheme ensures the purity of the input power supply and a stable output voltage supply, thus allowing for precise regulation of the output voltage.

[0022] Furthermore, the PWM / DAC weighting circuit 2 includes a unidirectional diode D1, a damping resistor R7, a PWM signal source, energy storage capacitors C7 and C8, and a resistor R8; one end of the unidirectional diode D1 is connected to the PWM signal source, and the other end is connected to the resistor R7; the resistor R7 is connected to the energy storage capacitors C7 and C8, and the energy storage capacitors C7 and C8 are connected to the resistor R8; the resistor R8 is connected to the feedback network, and the resistor R8 is connected to the first pin of the buck chip U1 through the feedback network to form a feedback loop;

[0023] During operation, the PWM signal generated by the PWM signal source first passes through a unidirectional diode D1, which prevents current from flowing back into the circuit and protects internal components. The signal then passes through a damping resistor R7 and enters an RC filter network composed of energy storage capacitors C7 and C8, converting the PWM signal into an analog voltage signal. This analog voltage signal is connected to the feedback network through a resistor R8 and then fed back to the first pin of the step-down chip U1, forming a closed-loop control system. This achieves the conversion from PWM digital signal to analog voltage and continuously and adjustablely controls the output voltage of the main circuit through the feedback mechanism, thereby realizing the soft start and speed control of the DC fan.

[0024] Furthermore, the PWM signal source can be connected to an AD voltage converter to enable the input of analog and digital speed control signals. The PWM signal source can be connected to the AD voltage converter, so it can receive both PWM digital speed control signals and analog speed control signals, allowing users to choose the most suitable speed control method according to the actual application scenario. This flexible design enables effective control of DC fan speed, enhancing the system's compatibility and application range.

[0025] Furthermore, resistors R1 and R3 form an overvoltage protection structure, which can limit the current to prevent damage to the buck chip U1. By using resistors R1 and R3 together to form an overvoltage protection structure, when the input voltage exceeds the normal range, these two resistors limit the current flowing through the buck chip U1 to prevent the chip from being damaged due to overvoltage.

[0026] Furthermore, the PWM / DAC weighting circuit 2 is also equipped with a unidirectional diode D1 to prevent current from flowing into the circuit in reverse and to protect the circuit from the influence of reverse voltage. This unidirectional diode D1 not only prevents current from flowing into the circuit in reverse, but also provides reverse voltage protection. When external conditions may cause reverse current or voltage, the unidirectional diode D1 will automatically prevent such abnormal current flow and protect the entire circuit from potential damage.

[0027] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0028] The above provides a detailed description of a unidirectional fan DC voltage regulation and speed control circuit provided in the embodiments of this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the technical solutions and core ideas of this application. Those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A unidirectional fan DC voltage regulating speed control circuit, characterized by, The application relates to a DC voltage reduction circuit (1) connected with a PWM / DAC power regulating circuit (2) for controlling the speed of a DC fan. The DC voltage reduction circuit (1) comprises input filter capacitors C1 and C5, a voltage reduction power inductor L1, and energy storage capacitors C2 and C3. The input filter capacitors C1 and C5 are connected in parallel between an input terminal VIN and the ground, for filtering high-frequency noise in the input power supply.

2. The unidirectional fan DC voltage regulating speed control circuit according to claim 1, wherein, The fourth pin of the voltage reduction chip U1 is connected to the input filter capacitors C1 and C5, and the second pin of the voltage reduction chip is connected to the ground through resistors R1 and R3, for controlling the opening and closing of the chip. The second pin of the voltage reduction chip U1 is connected to a resistor R2, for frequency setting. The first pin of the voltage reduction chip U1 is connected to a feedback network composed of resistors R4, R5A and R5B. The fifth and sixth pins of the voltage reduction chip U1 are both connected to the voltage reduction power inductor L1. The other end of the voltage reduction power inductor L1 is connected to the energy storage capacitors C2 and C3. The energy storage capacitors C2 and C3 are connected in parallel between an output terminal OUT and the ground, for smoothing the output voltage, and the output terminal OUT is connected to a load. The PWM / DAC power regulating circuit (2) comprises a unidirectional diode D1, a damping resistor R7, a PWM signal source, energy storage capacitors C7 and C8, and a resistor R8. One end of the unidirectional diode D1 is connected to the PWM signal source, and the other end is connected to the resistor R7.

3. The unidirectional fan DC voltage regulating speed control circuit according to claim 2, wherein, The resistor R7 is connected to the energy storage capacitors C7 and C8, and the energy storage capacitors C7 and C8 are connected to the resistor R8. The resistor R8 is connected to the feedback network, and the resistor R8 is connected to the first pin of the voltage reduction chip U1 through the feedback network, forming a feedback loop. The PWM signal source can be connected to an AD voltage converter, for realizing the access of analog and digital speed regulating signals. The resistors R1 and R3 form an overvoltage protection structure, which can limit the current to prevent damage to the voltage reduction chip U1.

4. The unidirectional fan DC voltage regulating speed control circuit according to claim 3, wherein, The PWM / DAC power regulating circuit (2) further comprises a unidirectional diode D1 for preventing current from flowing reversely into the circuit, and protecting the circuit from reverse voltage.

5. The unidirectional fan DC voltage regulating speed control circuit according to claim 2, wherein, ​ 6. The unidirectional fan DC voltage regulating speed control circuit according to claim 3, wherein, ​

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