A driving control circuit, circuit system and electronic device of a fan

Abstract

The utility model provides a kind of driving control circuit, circuit system and electronic equipment of fan, and the circuit includes: power module, temperature detection module, reference voltage module, hysteresis comparison module and drive control module.In the process of controlling fan circuit drive, each module is worked by the physical characteristics of its own hardware components, so the whole link does not need code execution or computing power support, thus avoiding the risk of software failure from the root.In addition, the power module integrated in the circuit can directly take power from the host device and store it, thus adapting to extreme scenarios without external power supply, expanding the application scenarios of the circuit.Finally, since the work of the driving control circuit does not require a program, it saves program editing and program debugging, thus reducing development costs.

Description

Technical Field

[0001] This utility model relates to the field of integrated circuits, and in particular to a fan drive control circuit, circuit system, and electronic device. Background Technology

[0002] Temperature control is a core technology in electronic devices, industrial machinery, and consumer appliances. Its core objective is to maintain critical components within a safe operating temperature range through heat dissipation or heating. With the increasing integration of electronic devices (such as 5G base stations and data center servers) and the development of industrial automation (such as smart factories and robots), the demand for heat dissipation exhibits the following trends: (1) High power density: Increased chip power consumption leads to the risk of local overheating (such as GPU temperature reaching above 90°C), requiring a rapid response temperature control solution; (2) Adaptability to extreme environments: Industrial equipment needs to operate stably in a wide temperature range of -40℃ to 85℃; (3) Low cost and high reliability: Consumer-grade devices (such as smart home and automotive electronics) require hardware solutions with no complex maintenance to avoid software vulnerabilities or crashes.

[0003] However, existing technologies for fan cooling control are usually based on the program logic of microcontrollers (such as MCUs). This not only requires external power supply, which limits the application scenarios, but is also susceptible to external environmental interference or code vulnerabilities (such as electromagnetic interference), resulting in insufficient reliability. Finally, because the control program requires corresponding sensor calibration and program debugging, it leads to long development time and high maintenance costs. Utility Model Content

[0004] This invention provides a fan drive control circuit, circuit system, and electronic device to solve the above-mentioned technical problems, so as to achieve low-cost, highly reliable, and wide-range application fan temperature control.

[0005] According to a first aspect of the present invention, a fan drive control circuit is provided, the drive control circuit comprising: The power supply module stores the input power supply voltage and converts it into a first power supply voltage and a second power supply voltage, respectively, and then outputs them. A temperature detection module is provided, wherein the power supply terminal of the temperature detection module is connected to the first power supply voltage, and the temperature detection module divides the first power supply voltage based on the ambient temperature to output a temperature detection voltage, wherein the temperature detection voltage is negatively correlated with the ambient temperature. A reference voltage module, wherein the power supply terminal of the reference voltage module is connected to the second power supply voltage, and the reference voltage module outputs a reference voltage based on the second power supply voltage; The hysteresis comparison module has its power supply terminal connected to the first power supply voltage, its first input terminal connected to the output terminal of the temperature detection module, and its second input terminal connected to the output terminal of the reference voltage module. The hysteresis comparison module outputs a drive control signal based on the magnitude relationship between the temperature detection voltage and the reference voltage. A drive control module is provided, wherein the power supply terminal of the drive control module is connected to the first power supply voltage, and the drive control module controls the operation or shutdown of the fan according to the drive control signal.

[0006] Optionally, the temperature detection module includes an NTC thermistor, a first voltage divider resistor, and a first filter capacitor; The first terminal of the NTC thermistor serves as the power supply terminal of the temperature detection module, and the second terminal of the NTC thermistor serves as the output terminal of the temperature detection module. It is also connected to the first terminal of the first voltage divider resistor and the first terminal of the first filter capacitor. The resistance value of the NTC thermistor is negatively correlated with the ambient temperature. The second terminals of the first voltage divider resistor and the first filter capacitor are both connected to ground.

[0007] Optionally, the NTC thermistor has a resistance of 10kΩ at 25℃, a negative temperature coefficient of 3950 at 25℃, and an operating temperature range of -55℃ to 125℃. The first voltage divider resistor is a metal film resistor, and the resistance of the first voltage divider resistor is 10kΩ; The first filter capacitor is a ceramic capacitor with a capacitance of 100nF and an operating temperature range of -55℃ to 125℃.

[0008] Optionally, the reference voltage module includes a reference voltage source, a second voltage divider resistor, and a third voltage divider resistor; The cathode of the reference voltage source serves as the power supply terminal of the reference voltage module, the anode of the reference voltage source is connected to ground, and the reference terminal of the reference voltage source is connected to the second terminal of the second voltage divider resistor and the first terminal of the third voltage divider resistor, respectively. The first terminal of the second voltage divider resistor is connected to the cathode of the reference voltage source. The first terminal of the third voltage divider resistor serves as the output terminal of the reference voltage module, and the second terminal of the third voltage divider resistor is connected to ground.

[0009] Optionally, the reference voltage source is a TL431 and outputs a reference voltage of 2.5V based on the second supply voltage.

[0010] Optionally, the hysteresis comparison module includes a voltage comparator, a positive feedback resistor, and a pull-up resistor; The power supply pin of the voltage comparator serves as the power supply terminal of the hysteresis comparator module, the inverting input terminal of the voltage comparator serves as the first input terminal of the hysteresis comparator module, the non-inverting input terminal of the voltage comparator serves as the second input terminal of the hysteresis comparator module, and the output terminal of the voltage comparator serves as the output terminal of the hysteresis comparator module. The first end of the pull-up resistor is connected to the output terminal of the voltage comparator, and the second end of the pull-up resistor is connected to the power supply pin of the voltage comparator. The first end of the positive feedback resistor is connected to the output terminal of the voltage comparator, and the second end of the positive feedback resistor is connected to the non-inverting input terminal of the voltage comparator.

[0011] Optionally, the drive control module includes an NMOS transistor, a first current-limiting resistor, and a freewheeling diode; The gate of the NMOS transistor is connected to the second terminal of the first current-limiting resistor, the first terminal of the first current-limiting resistor is connected to the drive control signal, the drain of the NMOS transistor is connected to the negative terminal of the fan and the cathode of the freewheeling diode, and the source of the NMOS transistor is connected to ground. The anode of the freewheeling diode and the positive terminal of the fan are both connected to the first power supply voltage.

[0012] Optionally, the first supply voltage is 5V and the second supply voltage is 3.3V.

[0013] According to a second aspect of the present invention, a circuit system is provided, including a drive control circuit for the fan.

[0014] According to a third aspect of the present invention, an electronic device is provided, including the aforementioned circuit system.

[0015] Compared with the prior art, the technical solution of this utility model has the following beneficial effects: In the fan drive control circuit provided by this utility model, firstly, the power supply module stores the input power supply voltage and converts it into a first supply voltage and a second supply voltage, respectively, and outputs them. Therefore, it can still work normally without external power input, thus broadening the application scenarios of the drive control circuit. Furthermore, the temperature detection module divides the first supply voltage based on the ambient temperature to output a temperature detection voltage, which is negatively correlated with the ambient temperature. The reference voltage module outputs a reference voltage based on the second supply voltage. The hysteresis comparison module outputs a drive control signal based on the relationship between the temperature detection voltage and the reference voltage. The drive control module controls the fan to operate or stop according to the drive control signal. Since the drive control circuit can control the fan solely through hardware architecture, it eliminates the risks of software vulnerabilities and chip crashes at the physical level, improving circuit reliability. Finally, since the drive control circuit does not require any programming, it saves on program editing and debugging, thereby reducing development costs. In summary, the drive control circuit of this utility model achieves low-cost, highly reliable, and wide-range application fan temperature control. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only 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 This is a schematic diagram of the fan drive control circuit provided in this embodiment; Figures 2 to 7 The circuit structure diagrams of the fan drive control circuit provided in this embodiment are as follows: Figures 1 to 6 . Detailed Implementation

[0018] As described in the background section, however, existing technologies for fan cooling control are usually based on the program logic of microcontrollers (such as MCUs). This not only requires external power supply, which limits the application scenarios, but is also easily affected by external environmental interference or has code vulnerabilities (such as electromagnetic interference), resulting in insufficient reliability. Finally, because the control program requires corresponding sensor calibration and program debugging, it leads to problems such as long development time and high maintenance costs.

[0019] In view of this, the technical solution of this utility model provides a new fan drive control circuit, including: a power supply module, a temperature detection module, a reference voltage module, a hysteresis comparison module, and a drive control module. During the fan control circuit operation, each module operates based on the physical characteristics of its own hardware components, thus requiring no code execution or computing power support throughout the entire process, fundamentally avoiding the risk of software failure. Furthermore, the integrated power supply module allows direct power drawing from and storage of data from the host device, adapting to extreme scenarios without external power and expanding the circuit's application scenarios. Finally, since the drive control circuit operates without any programming, it saves on program editing and debugging, thereby reducing development costs.

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0021] The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the utility model described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0022] The technical solution of this utility model will be described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0023] Figure 1 This is a schematic diagram of the fan drive control circuit provided in this embodiment.

[0024] Please refer to Figure 1 The fan drive control circuit provided in this embodiment includes: a power supply module 10, a temperature detection module 20, a reference voltage module 30, a hysteresis comparison module 40, and a drive control module 50.

[0025] The power module 10 stores the input power voltage VB and converts it into a first power supply voltage VCC1 and a second power supply voltage VCC2, respectively, and outputs them.

[0026] Figure 2 This is a schematic diagram of the circuit structure of the power module 10 provided in this embodiment.

[0027] Please refer to Figure 1 and Figure 2 Specifically, the power module 10 includes a 12V DC power input interface 11, a reverse polarity protection diode D1, a 5A self-resetting fuse 12, a 5V first voltage regulator chip 13, a 3.3V second voltage regulator chip 14, a second filter capacitor C2, and a third filter capacitor C3.

[0028] The positive input terminal of the DC power input interface 11 is connected to the anode of the reverse polarity protection diode D1, the first terminal of the resettable fuse 12, and the power input pin of the first voltage regulator chip 13. The output pin of the first voltage regulator chip 13 outputs a 5V voltage and is connected to the power input pin of the second voltage regulator chip 14 and the first terminal of the second filter capacitor C2. The output pin of the second voltage regulator chip 14 outputs a 3.3V voltage and is connected to the first terminal of the third filter capacitor C3. The negative input terminal of the DC power input interface 11, the cathode of the reverse polarity protection diode D1, the second terminal of the resettable fuse 12, the ground pin of the first voltage regulator chip 13, the ground pin of the second voltage regulator chip 14, the second terminal of the first filter capacitor C1, and the second terminal of the second filter capacitor C2 are all connected to the ground terminal.

[0029] Furthermore, the DC power input interface 11 has dimensions of 5.5mm*2.1mm.

[0030] Furthermore, the reverse polarity protection diode D1 is model 1N5822, the forward voltage drop of the reverse polarity protection diode D1 is 0.3V, and the maximum current flowing through the reverse polarity protection diode D1 is 3A.

[0031] Furthermore, the self-resetting fuse 12 is model JK-050, which automatically disconnects when the input current of the DC current input structure exceeds 5A to protect the circuit.

[0032] Furthermore, the first voltage regulator chip 13 is model LM1117, with an input voltage range of 6V~15V, an output voltage of 5V, an output current of 800mA, and the first power supply voltage VCC1 is equal to 5V.

[0033] Furthermore, the second voltage regulator chip 14 is model AMS1117, with an input voltage range of 4.5V~10V, an output voltage of 3.3V, an output current of 1A, and the second power supply voltage VCC2 equals 3.3V.

[0034] Furthermore, both the second filter capacitor C2 and the third filter capacitor C3 are composed of a 10μF electrolytic capacitor and a 100nF ceramic capacitor. The positive terminal of the electrode capacitor and one end of the ceramic capacitor together serve as the first terminal of the second filter capacitor C2 and the first terminal of the third filter capacitor C3. The negative terminal of the electrode capacitor and the other end of the ceramic capacitor together serve as the second terminal of the second filter capacitor C2 and the second terminal of the third filter capacitor C3.

[0035] The power supply terminal of the temperature detection module 20 is connected to the first power supply voltage VCC1. The temperature detection module 20 divides the first power supply voltage VCC1 based on the ambient temperature to output a temperature detection voltage Vsense. The temperature detection voltage Vsense is negatively correlated with the ambient temperature.

[0036] Please continue to refer to this. Figure 1 and Figure 3 Specifically, the temperature detection module 20 includes an NTC thermistor RNTC, a first voltage divider resistor R1, and a first filter capacitor C1.

[0037] The first terminal of the NTC thermistor RNTC serves as the power supply terminal of the temperature detection module 20, and the second terminal of the NTC thermistor RNTC serves as the output terminal of the temperature detection module 20. Both terminals are connected to the first terminal of the first voltage divider resistor R1 and the first terminal of the first filter capacitor C1. The resistance of the NTC thermistor RNTC is negatively correlated with the ambient temperature. This can be understood as follows: when the ambient temperature rises, the resistance of the NTC thermistor RNTC decreases, thereby reducing the magnitude of the temperature detection voltage Vsense; when the ambient temperature decreases, the resistance of the NTC thermistor RNTC increases, thereby increasing the magnitude of the temperature detection voltage Vsense. For example, when the ambient temperature is 50℃, the temperature detection voltage Vsense is 0.9V. When the ambient temperature is 40℃, the temperature detection voltage Vsense is 1.2V. The second terminals of both the first voltage divider resistor R1 and the first filter capacitor C1 are connected to ground.

[0038] Furthermore, the NTC thermistor RNTC is of the MF52 series, the resistance of the NTC thermistor RNTC at 25℃ is 10kΩ, the negative temperature coefficient of the NTC thermistor RNTC at 25℃ is 3950, and the operating temperature range of the NTC thermistor RNTC is -55℃ to 125℃.

[0039] Furthermore, the first voltage divider resistor R1 is a metal film resistor, and the resistance of the first voltage divider resistor R1 is 10kΩ.

[0040] Furthermore, the first filter capacitor C1 is a ceramic capacitor with a capacitance of 100nF and an operating temperature range of -55℃ to 125℃. Because the 100nF ceramic capacitor can filter out high-frequency noise, the accuracy of the temperature detection voltage Vsense is improved, thereby enhancing the accuracy of fan control based on ambient temperature.

[0041] Because the NTC thermistor RNTC supports normal operation within a temperature range of -55℃ to 125℃, and has a negative temperature coefficient of 3950 at room temperature, it is suitable for extreme industrial environments, thus further expanding the application scenarios of the circuit. Examples include extreme scenarios such as those around industrial ovens or outdoors.

[0042] The power supply terminal of the reference voltage module 30 is connected to the second power supply voltage VCC2, and the reference voltage module 30 outputs a reference voltage Vref based on the second power supply voltage VCC2.

[0043] Please continue to refer to this. Figure 1 and Figure 4 Specifically, the reference voltage module 30 includes a reference voltage source 31, a second voltage divider resistor R2, and a third voltage divider resistor R3; the cathode of the reference voltage source 31 serves as the power supply terminal of the reference voltage module 30, the anode of the reference voltage source 31 is connected to ground, and the reference terminal of the reference voltage source 31 is connected to the second terminal of the second voltage divider resistor R2 and the first terminal of the third voltage divider resistor R3, respectively; the first terminal of the second voltage divider resistor R2 is connected to the cathode of the reference voltage source 31; the first terminal of the third voltage divider resistor R3 serves as the output terminal of the reference voltage module 30, and the second terminal of the third voltage divider resistor R3 is connected to ground.

[0044] Furthermore, the reference voltage source 31 is a TL431, and outputs a reference voltage of 2.5V based on the second supply voltage VCC2. The temperature drift of the reference voltage source 31 is ±0.5% / ℃.

[0045] Based on the principle of voltage divider, and according to the output voltage of the reference voltage source 31, the resistance value of the second voltage divider resistor R2 and the resistance value of the third voltage divider resistor R3, the reference voltage Vref is approximately equal to 1.1V, and this 1.1V represents the set temperature of 40℃ when the fan stops working.

[0046] Since the set temperature when the fan stops working can be adjusted according to requirements, the output voltage of the reference voltage source 31, the resistance value of the second voltage divider resistor R2, and the resistance value of the third voltage divider resistor R3 can also be adaptively adjusted to match the set temperature when the fan stops working, and no limitation is made here.

[0047] The power supply terminal of the hysteresis comparison module 40 is connected to the first power supply voltage VCC1. The first input terminal of the hysteresis comparison module 40 is connected to the output terminal of the temperature detection module 20. The second input terminal of the hysteresis comparison module 40 is connected to the output terminal of the reference voltage module 30. The hysteresis comparison module 40 outputs a drive control signal Vout based on the magnitude relationship between the temperature detection voltage Vsense and the reference voltage Vref.

[0048] Please continue to refer to this. Figure 1 and Figure 5 Specifically, the hysteresis comparator module 40 includes a voltage comparator CMP, a positive feedback resistor R5, and a pull-up resistor R4. The power supply pin of the voltage comparator CMP serves as the power supply terminal of the hysteresis comparator module 40. The inverting input terminal of the voltage comparator CMP serves as the first input terminal of the hysteresis comparator module 40, the non-inverting input terminal of the voltage comparator CMP serves as the second input terminal of the hysteresis comparator module 40, and the output terminal of the voltage comparator CMP serves as the output terminal of the hysteresis comparator module 40. The first end of the pull-up resistor R4 is connected to the output terminal of the voltage comparator CMP, and the second end of the pull-up resistor R4 is connected to the power supply pin of the voltage comparator CMP. The first end of the positive feedback resistor R5 is connected to the output terminal of the voltage comparator CMP, and the second end of the positive feedback resistor R5 is connected to the non-inverting input terminal of the voltage comparator CMP.

[0049] Furthermore, the voltage comparator CMP is model LM393, operates on a single 5V power supply, and has an open-drain output structure. The voltage comparator CMP has a temperature range of -40℃ to 85℃.

[0050] Furthermore, the pull-up resistor R4 is used to enable the open-drain output to output a high level.

[0051] When the temperature detection voltage Vsense is less than or equal to the reference voltage Vref, it indicates that the ambient temperature is greater than the set temperature at which the fan stops working, i.e., the ambient temperature is greater than or equal to 50°C. Therefore, the voltage comparator CMP outputs a high level to turn on the NMOS transistor N1 in the drive control module 50, thereby enabling the fan to operate normally.

[0052] When the temperature detection voltage Vsense is greater than or equal to the reference voltage Vref, it indicates that the ambient temperature is less than or equal to the set temperature at which the fan stops working, i.e., the ambient temperature is less than or equal to 40°C. Therefore, the voltage comparator CMP outputs a low level to turn off the NMOS transistor N1 in the drive control module 50, thereby stopping the fan from running.

[0053] Meanwhile, to prevent the fan from frequently starting and stopping due to fluctuations in ambient temperature, the positive feedback resistor R5 will pull the input voltage of the non-inverting input terminal of the voltage comparator CMP from 1.1V to 1.2V after the voltage comparator CMP outputs a high level. This prevents the temperature sensing voltage Vsense from frequently switching its output due to fluctuations around 1.1V caused by ambient temperature variations. The positive feedback resistor R5 will also pull the input voltage of the non-inverting input terminal of the voltage comparator CMP from 1.1V or 1.2V to 1.0V after the voltage comparator CMP outputs a low level. This prevents the temperature sensing voltage Vsense from frequently switching its output due to fluctuations around 1.1V or 1.2V caused by ambient temperature variations.

[0054] Therefore, by adjusting the input voltage at the non-inverting input of the comparator when the comparator outputs a high or low level, the start-up and stop thresholds of the fan can be adjusted, thereby improving the circuit's anti-interference capability, avoiding frequent fan start-ups and stops, and thus greatly extending the fan's lifespan.

[0055] The power supply terminal of the drive control module 50 is connected to the first power supply voltage VCC1, and the drive control module 50 controls the operation or shutdown of the fan according to the drive control signal Vout.

[0056] Please continue to refer to this. Figure 1 and Figure 6 The drive control module 50 includes an NMOS transistor N1, a first current-limiting resistor R5, and a freewheeling diode D2. The gate of the NMOS transistor N1 is connected to the second terminal of the first current-limiting resistor R5, the first terminal of the first current-limiting resistor R5 is connected to the drive control signal Vout, the drain of the NMOS transistor N1 is connected to the negative terminal of the fan and the cathode of the freewheeling diode D2, and the source of the NMOS transistor N1 is connected to ground. The anode of the freewheeling diode D2 and the positive terminal of the fan are both connected to the first power supply voltage VCC1.

[0057] Furthermore, the resistance of the first current-limiting resistor R5 is 1KΩ.

[0058] Furthermore, the forward voltage drop of the freewheeling diode D2 is 0.4V, and the maximum current flowing through the freewheeling diode D2 is 1A.

[0059] Please continue to refer to this. Figure 1 and Figure 7 In other embodiments, the drive control module 50 further includes a green LEDD3, a red LEDD4, a second current-limiting resistor R6, and a third current-limiting resistor R7. The anode of the green LEDD3 is connected to the first supply voltage VCC1, the cathode of the green LEDD3 is connected to the first terminal of the second current-limiting resistor R6, and the second terminal of the second current-limiting resistor R6 is connected to the drain of the NMOS transistor N1. When the voltage comparator CMP outputs a high level and the NMOS transistor N1 is turned on, the green LEDD3 is lit.

[0060] The anode of the red LEDD4 is connected to the first terminal of the third current-limiting resistor R7, the second terminal of the third current-limiting resistor R7 is connected to the first supply voltage VCC1, and the cathode of the red LEDD4 is connected to the output terminal of the voltage comparator CMP. When the voltage comparator CMP outputs a low level, the red LEDD4 is lit.

[0061] Furthermore, the resistance of the second current-limiting resistor R6 is 56Ω, and the resistance of the third current-limiting resistor R7 is 82Ω.

[0062] In summary, the fan drive control circuit provided in this embodiment achieves the "temperature acquisition → threshold judgment → fan start / stop" process using only discrete components such as NTC thermistors, voltage comparators, NMOS transistors, reference voltage sources, and resistors. This physically eliminates risks such as software vulnerabilities and chip crashes, increasing the mean time between failures (MTBF) to over 100,000 hours and significantly improving circuit reliability. Furthermore, since no program editing or debugging is required, the development cost of the circuit is reduced. Finally, the power supply module stores the input power voltage and converts it into a first supply voltage and a second supply voltage for output, allowing it to operate normally even without external power input, thus broadening the circuit's application scenarios.

[0063] Furthermore, since the core components of the circuit are all industrial-grade models, such as the NTC thermistor supporting temperature measurement from -55℃ to 125℃, the voltage comparator operating temperature from -40℃ to 85℃, and the MOSFET temperature resistance... - With a temperature range of 55℃ to 150℃, it is suitable for extreme industrial environments, thereby further expanding the application scenarios of the circuit.

[0064] Furthermore, the hysteresis characteristics provided by the hysteresis comparison module suppress small fluctuations in ambient temperature, and the first filter capacitor filters high-frequency noise, thereby greatly improving the circuit's anti-dampness capability and extending the fan's lifespan.

[0065] Other embodiments also provide a circuit system including the drive control circuit for the fan.

[0066] Other embodiments also provide an electronic device including the circuit system.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, 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 or all of the technical features therein. Such 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 utility model.

Claims

1. A fan drive control circuit, characterized in that, The drive control circuit includes: a power supply module that stores the input power supply voltage and converts it into a first power supply voltage and a second power supply voltage, and outputs them respectively; a temperature detection module whose power supply terminal is connected to the first power supply voltage, and which divides the first power supply voltage based on the ambient temperature to output a temperature detection voltage, wherein the temperature detection voltage and the ambient temperature are negatively correlated; a reference voltage module whose power supply terminal is connected to the second power supply voltage, and which outputs a reference voltage based on the second power supply voltage; a hysteresis comparator module whose power supply terminal is connected to the first power supply voltage, whose first input terminal is connected to the output terminal of the temperature detection module, whose second input terminal is connected to the output terminal of the reference voltage module, and which outputs a drive control signal based on the magnitude relationship between the temperature detection voltage and the reference voltage; and a drive control module whose power supply terminal is connected to the first power supply voltage, and which controls the operation or shutdown of the fan according to the drive control signal.

2. The fan drive control circuit according to claim 1, characterized in that, The temperature detection module includes an NTC thermistor, a first voltage divider resistor, and a first filter capacitor. The first terminal of the NTC thermistor serves as the power supply terminal of the temperature detection module, and the second terminal of the NTC thermistor serves as the output terminal of the temperature detection module. It is also connected to the first terminal of the first voltage divider resistor and the first terminal of the first filter capacitor. The resistance value of the NTC thermistor is negatively correlated with the ambient temperature. The second terminals of the first voltage divider resistor and the first filter capacitor are both connected to ground.

3. The fan drive control circuit according to claim 2, characterized in that, The NTC thermistor has a resistance of 10kΩ at 25℃, a negative temperature coefficient of 3950 at 25℃, and an operating temperature range of -55℃ to 125℃. The first voltage divider resistor is a metal film resistor, and the resistance of the first voltage divider resistor is 10kΩ; The first filter capacitor is a ceramic capacitor with a capacitance of 100nF and an operating temperature range of -55℃ to 125℃.

4. The fan drive control circuit according to claim 1, characterized in that, The reference voltage module includes a reference voltage source, a second voltage divider resistor, and a third voltage divider resistor; The cathode of the reference voltage source serves as the power supply terminal of the reference voltage module, the anode of the reference voltage source is connected to the ground terminal, and the reference terminal of the reference voltage source is connected to the second terminal of the second voltage divider resistor and the first terminal of the third voltage divider resistor, respectively. The first terminal of the second voltage divider resistor is connected to the cathode of the reference voltage source; The first end of the third voltage divider resistor serves as the output terminal of the reference voltage module, and the second end of the third voltage divider resistor is connected to ground.

5. The fan drive control circuit according to claim 4, characterized in that, The reference voltage source is a TL431, and it outputs a reference voltage of 2.5V based on the second supply voltage.

6. The fan drive control circuit according to claim 1, characterized in that, The hysteresis comparison module includes a voltage comparator, a positive feedback resistor, and a pull-up resistor; The power supply pin of the voltage comparator serves as the power supply terminal of the hysteresis comparator module, the inverting input terminal of the voltage comparator serves as the first input terminal of the hysteresis comparator module, the non-inverting input terminal of the voltage comparator serves as the second input terminal of the hysteresis comparator module, and the output terminal of the voltage comparator serves as the output terminal of the hysteresis comparator module. The first end of the pull-up resistor is connected to the output terminal of the voltage comparator, and the second end of the pull-up resistor is connected to the power supply pin of the voltage comparator. The first end of the positive feedback resistor is connected to the output terminal of the voltage comparator, and the second end of the positive feedback resistor is connected to the non-inverting input terminal of the voltage comparator.

7. The fan drive control circuit according to claim 1, characterized in that, The drive control module includes an NMOS transistor, a first current-limiting resistor, and a freewheeling diode. The gate of the NMOS transistor is connected to the second terminal of the first current-limiting resistor, the first terminal of the first current-limiting resistor is connected to the drive control signal, the drain of the NMOS transistor is connected to the negative terminal of the fan and the cathode of the freewheeling diode, and the source of the NMOS transistor is connected to ground. The anode of the freewheeling diode and the positive terminal of the fan are both connected to the first power supply voltage.

8. The fan drive control circuit according to any one of claims 1 to 7, characterized in that, The first supply voltage is 5V, and the second supply voltage is 3.3V.

9. A circuit system, characterized in that, Includes the drive control circuit for the fan as described in any one of claims 1 to 8.

10. An electronic device, characterized in that, Includes the circuit system described in claim 9.

Images