Automatic fan speed regulating system based on triode temperature control
By using a transistor-based automatic fan speed control system, the temperature characteristics of the transistor are utilized to achieve automatic fan speed adjustment, solving the problems of high energy consumption and increased cost of DC fans in electronic devices, and providing a simple, reliable and efficient heat dissipation solution.
Patent Information
- Application Number
- CN202520292048.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-24
- Publication Date
- 2026-02-03
- Estimated Expiration
- 2035-02-24
AI Technical Summary
Existing DC fans cannot achieve automatic speed control in electronic devices, resulting in high energy consumption and increased costs.
An automatic fan speed control system based on transistor temperature control is adopted. By utilizing the temperature characteristics of the transistor, the fan speed is changed through heat conduction to achieve automatic speed control.
This technology enables the fan to automatically adjust its speed based on temperature changes, reducing energy consumption, simplifying circuit design, lowering costs, and improving heat dissipation efficiency.
Smart Images
Figure CN223868214U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of fan speed control technology, specifically to an automatic fan speed control system based on transistor temperature control. Background Technology
[0002] DC brushless fans are widely used in electronic products, playing a crucial role in heat dissipation, especially in high-power electronic devices such as high-power PoE switches. The heat generated by internal ICs and power modules in these devices needs to be dissipated by DC fans. Most current DC fans are powered by 12V. When a fixed 12VDC voltage is applied, the fan will always operate at maximum speed, resulting in high energy consumption. Controlling the fan speed requires an additional controller or CPLD circuit, increasing costs. Manually reducing the voltage is time-consuming and cannot accurately adjust the fan speed based on the actual heat generated by the product. Therefore, our question is: how can we achieve automatic fan speed control without requiring additional circuitry for controlling the fan speed? Utility Model Content
[0003] This invention provides a transistor-based automatic fan speed control system to solve the technical problem of how to achieve automatic speed control of a DC fan without using a circuit to control the fan speed.
[0004] The technical solution of this utility model to solve the above-mentioned technical problems is as follows:
[0005] An automatic fan speed control system based on transistor temperature control is provided. The system architecture is as follows: the positive terminal of a 12V DC power supply DC1 is connected to one end of voltage divider resistors R1 and R2. The other end of voltage divider resistor R1 is connected to one end of a sliding rheostat RX1 and the positive terminal of a rectifier diode D1. The other end of the sliding rheostat RX1 is connected to the negative terminal of the 12V DC power supply DC1. The negative terminal of the rectifier diode D1 is also connected to the negative terminal of the DC power supply DC1. The sliding rheostat RX1 and the rectifier diode D1 are connected in parallel. The other end of the voltage divider resistor R2 is connected to the positive terminal of the rectifier diode D2. The positive terminal of the rectifier diode D2 is connected to the collector of the transistor Q1, and the emitter of the transistor Q1 is connected to the negative terminal of the DC power supply DC1. The base of the transistor Q1 is connected to the slider of the sliding rheostat RX1. The positive terminal of the DC fan FAN1 is connected to the positive terminal of the DC power supply DC1, and the negative terminal of the DC fan FAN1 is connected to the negative terminal of the rectifier diode D2. When the speed control system is powered on, as the heat from the heat source device is conducted to the transistor Q1, the speed of the DC fan FAN1 automatically increases when the temperature rises and automatically decreases when the temperature drops.
[0006] Furthermore, the voltage divider resistor R1 has a resistance of 1KΩ, and the voltage divider resistor R2 has a resistance of 300Ω; the rectifier diodes D1 and D2 are both silicon rectifier diodes of type 1N4007 with a forward voltage drop of 0.7V; the maximum resistance of the sliding rheostat RX1 is 1KΩ; the transistor Q1 is a BC547 NPN bipolar junction transistor; the DC fan FAN1 is a PIA040F12L model fan, and the heat source device is located near the transistor Q1.
[0007] Furthermore, the slider position of the sliding rheostat RX1 can be adjusted according to the needs of the actual application scenario to optimize the initial speed of the DC fan FAN1 when it starts.
[0008] Furthermore, the transistor Q1 is installed in a heat-concentrated area next to the main chip or main power chip of the application product.
[0009] Furthermore, the DC fan FAN1 operates at a voltage range of 12V to ensure stable operation under different voltage inputs; the positive terminal of the DC fan FAN1 is connected to the positive terminal of the DC power supply DC1, and the negative terminal of the DC fan FAN1 is connected to the negative terminal of the rectifier diode D2 to form a complete current loop; when the current of the rectifier diode D2 is adjusted, the speed of the DC fan FAN1 is dynamically adjusted.
[0010] Furthermore, the speed control system also includes a temperature sensor for real-time monitoring of temperature changes near the transistor Q1 and feeding the temperature data back to the control system.
[0011] Furthermore, the speed control system also includes a manual adjustment switch for emergency control of manually adjusting the speed of the DC fan FAN1.
[0012] The beneficial effects of this utility model are:
[0013] This invention provides a transistor-based automatic fan speed control system, which achieves automatic fan speed adjustment based on temperature changes through a simple circuit design. The system utilizes the temperature characteristics of a transistor to conduct heat to the transistor; as the temperature rises, the transistor's amplification factor increases, thereby changing the fan speed. This design not only eliminates the need for an additional controller or CPLD circuit, reducing system complexity and cost, but also enables the fan to automatically adjust its speed according to actual temperature requirements, thus significantly reducing energy consumption while ensuring effective heat dissipation. Furthermore, the system uses readily available standard components, has simple circuit connections, and is easy to manufacture and maintain, making it ideal for various electronic devices requiring efficient heat dissipation. It not only solves the problems of high cost and complexity in existing technologies but also provides a simple, reliable, and efficient automatic fan speed control solution. Attached Figure Description
[0014] Figure 1 This is the circuit diagram of this utility model. Detailed Implementation
[0015] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model. Furthermore, it should be understood that the specific embodiments described herein are merely for explaining this utility model and are not intended to limit this utility model.
[0016] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows for communication; 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. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.
[0017] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0018] The following disclosure provides numerous different embodiments or examples for implementing various structures of the present invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of the invention. 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, examples of various specific processes and materials are provided in this invention; however, those skilled in the art will recognize the application of other processes and / or the use of other materials.
[0019] The present invention provides the following preferred embodiments:
[0020] This invention provides a transistor-based automatic fan speed control system, aiming to achieve automatic fan speed adjustment based on temperature changes through a simple circuit design. This system requires no additional controller or complex circuitry. Utilizing the temperature characteristics of a transistor, heat is conducted to the transistor; as the temperature rises, the transistor's amplification factor increases, thereby altering the fan speed. The following is a detailed description of the system's implementation, outlining the connection relationships of each component and its working principle.
[0021] like Figure 1As shown, the speed control system is based on a 12V DC power supply DC1. It utilizes a circuit consisting of resistors, diodes, a variable resistor, a transistor, and a fan to achieve temperature sensing and fan speed control. Specifically, the positive terminal of the 12V DC power supply DC1 is connected to one end of voltage divider resistors R1 and R2. The other end of voltage divider resistor R1 is connected to one end of the variable resistor RX1 and the positive terminal of rectifier diode D1. The other end of the variable resistor RX1 is connected to the negative terminal of the 12V DC power supply DC1. The negative terminal of rectifier diode D1 is also connected to the negative terminal of DC1, and the variable resistor RX1 and rectifier diode D1 are connected in parallel. The other end of voltage divider resistor R2 is connected to the positive terminal of rectifier diode D2. The negative terminal of rectifier diode D2 is connected to the collector of transistor Q1, and the emitter of transistor Q1 is connected to the negative terminal of DC1. The base of transistor Q1 is connected to the slider of variable resistor RX1, the positive terminal of DC fan FAN1 is connected to the positive terminal of DC power supply DC1, and the negative terminal of DC fan FAN1 is connected to the negative terminal of rectifier diode D2.
[0022] Furthermore, when the system is powered on, as heat from the heat source is conducted to transistor Q1, the speed of DC fan FAN1 automatically increases when the temperature rises and automatically decreases when the temperature drops. This process is achieved through the temperature characteristics of transistor Q1. As the temperature rises, the amplification factor of transistor Q1 increases, and the collector current increases accordingly, which in turn leads to an increase in the negative voltage of rectifier diode D2, thereby increasing the speed of fan FAN1. Conversely, when the temperature decreases, the amplification factor of transistor Q1 decreases, the collector current decreases, and the speed of fan FAN1 also decreases.
[0023] Furthermore, the specific parameters of each component in the system are as follows: the voltage divider resistor R1 has a resistance of 1KΩ, and the voltage divider resistor R2 has a resistance of 300Ω; rectifier diodes D1 and D2 are both 1N4007 silicon rectifier diodes with a forward voltage drop of 0.7V; the maximum resistance of the sliding rheostat RX1 is 1KΩ; the transistor Q1 is a BC547 NPN bipolar junction transistor; the DC fan FAN1 is a PIA040F12L model fan, and the heat source is located near the transistor Q1. The selection of these components ensures the stability and reliability of the system under different temperature conditions.
[0024] Understandably, the slider position of the variable resistor RX1 can be adjusted according to the needs of the actual application scenario to optimize the initial speed of the DC fan FAN1 during startup. By adjusting the slider position of the variable resistor RX1, the voltage range between the base and emitter of the transistor Q1 can be changed, thereby affecting the initial operating state of the fan FAN1. In some applications, it may be necessary for the fan to maintain a low speed during startup to reduce noise and energy consumption; while in other applications, it may be necessary for the fan to quickly enter a high-speed state for rapid heat dissipation.
[0025] Furthermore, transistor Q1 is installed in a heat-concentrated area near the main chip or main power chip of the application product to ensure that it can promptly sense temperature changes. The installation position of transistor Q1 determines its sensitivity to temperature changes, thus directly affecting the response speed and accuracy of fan FAN1. By installing transistor Q1 in critical heat-generating components, it can be ensured that fan FAN1 can respond to temperature changes in the first instance, improving the overall heat dissipation efficiency of the system.
[0026] The working process of this utility model is described in detail below:
[0027] When the 12V DC power supply DC1 is powered on, the current is first shunted through the voltage divider resistors R1 and R2. Part of the current returns to the negative terminal of the power supply through the variable resistor RX1 and the rectifier diode D1, while the other part flows through the voltage divider resistor R2 and the rectifier diode D2 into the collector of transistor Q1. At this time, the base of transistor Q1 receives a certain bias voltage through the slider of the variable resistor RX1, causing transistor Q1 to be in a conducting state. Since the emitter of transistor Q1 is directly connected to the negative terminal of the power supply, its collector current flows into the negative terminal of the DC fan FAN1 through the negative terminal of the rectifier diode D2, forming a complete current loop.
[0028] As the product operates for longer periods, the heat generated by the main chip or main power chip is gradually conducted to transistor Q1, causing the temperature to rise and increasing the amplification factor of transistor Q1. According to the characteristics of transistors, the increased amplification factor leads to an increase in collector current, which in turn increases the negative voltage of rectifier diode D2, thereby increasing the speed of DC fan FAN1. When the temperature decreases, the amplification factor of transistor Q1 decreases, the collector current decreases, the negative voltage of rectifier diode D2 also decreases, and the speed of fan FAN1 decreases accordingly. This process is continuous and reversible, ensuring that the fan can automatically adjust its speed according to temperature changes.
[0029] Furthermore, to improve system reliability and flexibility, the system can also include a temperature sensor to monitor temperature changes near transistor Q1 in real time and feed the temperature data back to the control system. The introduction of the temperature sensor allows the system to more accurately control the speed of fan FAN1, avoiding misjudgments caused by temperature fluctuations. In addition, the temperature sensor can also be used for fault detection, ensuring that the system can take timely measures under abnormal temperature conditions, guaranteeing the safe operation of the equipment.
[0030] Furthermore, the system may also include a manual adjustment switch for emergency control, allowing manual adjustment of the DC fan FAN1 speed. The introduction of the manual adjustment switch provides users with an emergency control mechanism; in case the automatic speed control function fails or special operations are required, users can quickly adjust the speed of fan FAN1 to ensure normal equipment operation. In addition, the manual adjustment switch can also be used during commissioning and maintenance to help engineers better understand the system's performance and behavior.
[0031] Taking a high-power switch as an example, this switch generates a significant amount of heat during prolonged operation, especially in the main chip and power module. By installing the transistor-based automatic fan speed control system of this invention in these critical heat-generating components, the fan can automatically adjust its speed according to temperature changes without adding additional control circuitry. The transistor Q1 in the system is installed near the main chip and power module to ensure timely temperature sensing. The slider position of the variable resistor RX1 can be adjusted according to actual needs to optimize the initial fan speed upon startup. During system operation, the temperature sensor monitors temperature changes in real time and feeds the data back to the control system, ensuring the fan can accurately adjust its speed based on temperature variations. Furthermore, a manual adjustment switch provides emergency control in special circumstances to ensure the normal operation of the equipment.
[0032] The advantage of this invention lies in providing a transistor-based automatic fan speed control system. Through a simple circuit design, it achieves automatic fan speed adjustment based on temperature changes. This system requires no additional controller or complex circuitry. Utilizing the temperature characteristics of the transistor, heat is conducted to the transistor; as the temperature rises, the transistor's amplification factor increases, thereby altering the fan speed. The selection of components ensures stability and reliability under different temperature conditions, and the introduction of a temperature sensor and a manual adjustment switch further enhances the system's reliability and flexibility. This system is suitable for various electronic devices requiring efficient heat dissipation, significantly reducing energy consumption, extending device lifespan, and improving heat dissipation efficiency without affecting device performance.
[0033] The beneficial effects of this utility model are specifically reflected in the fact that the above description is only a preferred embodiment of this utility model and is not intended to limit this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.
Claims
1. A fan automatic speed control system based on transistor temperature control, characterized in that, The speed control system is structured as follows: the positive terminal of the 12V DC power supply DC1 is connected to one end of voltage divider resistors R1 and R2 respectively; the other end of voltage divider resistor R1 is connected to one end of a sliding rheostat RX1 and the positive terminal of rectifier diode D1 respectively; the other end of the sliding rheostat RX1 is connected to the negative terminal of the 12V DC power supply DC1; the negative terminal of rectifier diode D1 is also connected to the negative terminal of the DC power supply DC1; the sliding rheostat RX1 and the rectifier diode D1 are connected in parallel; the other end of voltage divider resistor R2 is connected to the positive terminal of rectifier diode D2; the rectifier diode D1... The negative terminal of diode D2 is connected to the collector of transistor Q1, and the emitter of transistor Q1 is connected to the negative terminal of DC power supply DC1; the base of transistor Q1 is connected to the slider of sliding rheostat RX1; the positive terminal of DC fan FAN1 is connected to the positive terminal of DC power supply DC1, and the negative terminal of DC fan FAN1 is connected to the negative terminal of rectifier diode D2; when the speed control system is powered on, as the heat from the heat source device is conducted to transistor Q1, the speed of DC fan FAN1 automatically increases when the temperature rises, and automatically decreases when the temperature drops.
2. The automatic fan speed control system based on transistor temperature control according to claim 1, characterized in that, The voltage divider resistor R1 has a resistance of 1KΩ, and the voltage divider resistor R2 has a resistance of 300Ω; the rectifier diodes D1 and D2 are both silicon rectifier diodes of type 1N4007 with a forward voltage drop of 0.7V; the maximum resistance of the sliding rheostat RX1 is 1KΩ; the transistor Q1 is a BC547 NPN bipolar junction transistor; the DC fan FAN1 is a PIA040F12L fan, and the heat source device is located near the transistor Q1.
3. The automatic fan speed control system based on transistor temperature control according to claim 1, characterized in that, The slider position of the sliding rheostat RX1 can be adjusted according to the needs of the actual application scenario to optimize the initial speed of the DC fan FAN1 when it starts.
4. The automatic fan speed control system based on transistor temperature control according to claim 1, characterized in that, The transistor Q1 is installed in the heat-concentrated area next to the main chip or main power chip of the application product.
5. The automatic fan speed control system based on transistor temperature control according to claim 1, characterized in that, The DC fan FAN1 operates at a voltage range of 12V to ensure stable operation under different voltage inputs. The positive terminal of the DC fan FAN1 is connected to the positive terminal of the DC power supply DC1, and the negative terminal of the DC fan FAN1 is connected to the negative terminal of the rectifier diode D2 to form a complete current loop. When the current of the rectifier diode D2 is adjusted, the speed of the DC fan FAN1 is dynamically adjusted.
6. The automatic fan speed control system based on transistor temperature control according to claim 1, characterized in that, The speed control system also includes a temperature sensor for real-time monitoring of temperature changes near the transistor Q1 and feeding the temperature data back to the control system.
7. The automatic fan speed control system based on transistor temperature control according to claim 1, characterized in that, The speed control system also includes a manual adjustment switch for emergency control to manually adjust the speed of the DC fan FAN1.