Fan control circuit

Abstract

The utility model provides a fan control circuit which comprises a charging interface USB1, a driving unit M1 and a control unit U1, the input end of the driving unit M1 is connected with the charging interface USB1, the output end of the driving unit M1 is connected with the control unit U1, the charging interface USB1 supplies power to the driving unit M1 and the control unit U1, and the control unit U1 supplies power to the driving unit M1 and the control unit U1. A voltage division protection circuit is connected between the driving unit M1 and the control unit U1, the voltage division protection circuit comprises a first resistor R13 and a third switch tube Q3, the control unit U1 sends a high level signal to a pin FAN2 to enable the third switch tube Q3 to be conducted, and normal work of the driving unit M1 is achieved; and the control unit U1 sends a low-level signal to a pin FAN2 to cut off the third switch tube Q3 and stop the driving unit M1, the control unit generates a signal to realize speed regulation, and the safety, the energy efficiency and the control flexibility are remarkably improved in combination with a voltage division protection circuit and an optimized voltage conversion module.

Description

Technical Field

[0001] This utility model belongs to the field of electronic circuit technology, and specifically relates to a fan control circuit. Background Technology

[0002] In actual production, traditional fans mostly use mechanical switches or fixed speed settings, which cannot achieve multi-level speed adjustment, resulting in a poor user experience. At the same time, the circuit often lacks real-time monitoring and dynamic response to overcurrent, overvoltage, and temperature anomalies, making it easy for components to be damaged due to stalling or power fluctuations. A single voltage power supply cannot meet the high power requirements of the motor and the low power consumption characteristics of the logic circuit, resulting in low overall efficiency. Utility Model Content

[0003] (1) Technical problems to be solved

[0004] This invention provides a fan control circuit designed to solve the problems of limited speed control function, lack of real-time monitoring and protection, and high energy consumption.

[0005] (2) Technical solution

[0006] This utility model provides a fan control circuit, including a charging interface USB1, a drive unit M1 and a control unit U1. The input end of the drive unit M1 is connected to the charging interface USB1, and the output end is connected to the control unit U1. The charging interface USB1 supplies power to the drive unit M1 and the control unit U1, and the control unit U1 controls the start and stop of the drive unit M1.

[0007] The driving unit M1 and the control unit U1 are connected by a voltage divider protection circuit. The voltage divider protection circuit includes a first resistor R13 and a third switch Q3. The drain D of the third switch Q3 is connected to the driving unit M1, the gate G is connected to the pin FAN2 of the control unit U1, and the source S is connected to the first resistor R13. The other end of the first resistor R13 is grounded. The pin DET2 of the control unit U1 is also connected to the resistor R13.

[0008] The control unit U1 sends a high-level signal to pin FAN2 to turn on the third switch Q3, enabling the drive unit M1 to operate normally. When pin DET2 of the control unit U1 detects that the voltage at the upper end of the resistor R13 is higher than the set threshold, the control unit U1 sends a low-level signal to pin FAN2 to turn off the third switch Q3 and stop the drive unit M1 from working.

[0009] Furthermore, the voltage divider protection circuit also includes a resistor R14, one end of which is connected to pin DET2 and the other end is connected to resistor R13. The third switch Q3 is an NMOSFET.

[0010] Furthermore, a voltage regulator U3 is provided between the output terminal of the charging interface USB1 and the control unit U1 to stabilize the input voltage of the control unit U1 at 3.3V.

[0011] Furthermore, a diode D6 is provided between pin DET2 of the control unit U1 and the output terminal of the voltage regulator U3, and the input terminal of the diode D6 is connected to pin DET2.

[0012] Furthermore, a boost circuit is connected between the charging interface USB1 and the driving unit M1, and the boost circuit includes an inductor L1, a control chip U4, and a capacitor C2.

[0013] Furthermore, a speed control circuit is provided between the boost circuit and the drive unit M1. The speed control circuit includes resistors R10, R11, R12 and R21 connected in series, and the output terminal of resistor R21 is grounded.

[0014] Furthermore, the speed control circuit also includes a fourth switching transistor Q4, the drain D of the fourth switching transistor Q4 is connected to the output terminal of the resistor R10, the source S is grounded, and the gate G is connected to the pin P14 of the control unit U1.

[0015] Furthermore, the speed control circuit also includes a fifth switching transistor Q5, the drain D of the fifth switching transistor Q5 is connected to the output terminal of the resistor R12, the source S is grounded, and the gate G is connected to the pin P16 of the control unit U1.

[0016] Furthermore, a charging circuit is provided between the charging interface USB1 and the boost circuit. The charging circuit includes a battery BAT1 and a first switching transistor Q1. The drain D of the first switching transistor Q1 is connected to the battery BAT1, and the source S and gate G are respectively connected to the output terminal of the charging interface USB1.

[0017] Furthermore, the charging circuit also includes a charging chip U2, the output terminal of the charging interface USB1 is connected to the VCC pin of the charging chip U2, and the BAT pin of the charging chip U2 is connected to the battery BAT1.

[0018] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0019] 1. Speed ​​regulation is achieved by generating signals through the control unit. Combined with voltage divider protection circuit and optimized voltage conversion module, safety, energy efficiency and control flexibility are significantly improved.

[0020] 2. By setting up pressure divider detection and temperature monitoring, a multi-level protection system is formed.

[0021] 3. The boost and buck circuits operate independently, respectively meeting the high power requirements of the motor and the low power consumption requirements of the logic circuit, thereby improving overall energy efficiency. Attached Figure Description

[0022] Figure 1 This is a flowchart of the present invention.

[0023] Figure 2 This is a schematic diagram of the overall circuit of this utility model.

[0024] Figure 3 This is a schematic diagram of the power supply circuit of this utility model.

[0025] Figure 4 This is a schematic diagram of the boost circuit of this utility model.

[0026] Figure 5 This is a schematic diagram of the voltage divider protection circuit of this utility model.

[0027] Figure 6 This is a schematic diagram of the voltage regulator and control unit of this utility model.

[0028] Figure 7 This is a schematic diagram of the speed control circuit of this utility model.

[0029] Figure 8 This is a schematic diagram of the first-stage speed regulation of this utility model.

[0030] Figure 9 This is a schematic diagram of the two-stage speed regulation of this utility model.

[0031] Figure 10 This is a schematic diagram of the three-stage speed regulation of this utility model.

[0032] Figure 11 This is a schematic diagram of the button connection of this utility model.

[0033] Figure 12 This is a schematic diagram of the charging circuit of this utility model.

[0034] Figure 13 This is a schematic diagram of the charging indicator light of this utility model.

[0035] Figure 14 This is a schematic diagram of the detection circuit of this utility model.

[0036] Figure labels: 1-Charging circuit, 2-Voltage divider protection circuit, 3-Detection circuit, 4-Boost circuit, 5-Speed ​​control circuit. Detailed Implementation

[0037] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention.

[0038] like Figure 1-14 As shown, this utility model discloses a fan control circuit, including a charging interface USB1, a drive unit M1 and a control unit U1. The input end of the drive unit M1 is connected to the charging interface USB1, and the output end is connected to the control unit U1. The charging interface USB1 supplies power to the drive unit M1 and the control unit U1, and the control unit U1 controls the start and stop of the drive unit M1.

[0039] In this embodiment, as Figure 2-4 As shown, the charging interface USB is a Type-C interface, and the external power supply is 5V. In use, the external power supply powers the charging interface USB1 to drive the drive unit M1 to operate the fan and output air. A fuse F1 is connected between the charging interface USB1 and the drive unit M1. In this embodiment, the rated current of the fuse F1 is 1A and the rated voltage is 6V. By setting the fuse F1, the resistance increases to limit the current in case of abnormal overcurrent, preventing the drive unit M1 from being damaged due to accidental overload. A diode D4 is also provided between the external power supply and ground. The diode D4 is a transient voltage suppression device used to suppress instantaneous voltage and protect circuit components.

[0040] like Figure 4As shown, since the voltage provided by the charging interface USB1 is insufficient to drive the driving unit M1, a boost circuit 4 is connected between the charging interface USB1 and the driving unit M1. The boost circuit 4 includes an inductor L1, a control chip U4, a capacitor C2, and a diode D2. One end of the inductor L1 is connected to the output terminal of the charging interface USB1, and the other end is connected to the capacitor C2. The other end of the capacitor C2 is grounded. The pin SW of the control chip U4 is connected between the inductor L1 and the capacitor C2. When the pin SW of the control chip U4 is turned on, the inductor L1 stores energy. When pin SW of the control chip U4 is cut off, the input voltage is increased to a higher output voltage by combining the unidirectional conductivity of diode D2. The inductor L1 releases energy to the capacitor C2 to achieve voltage boost. By setting the voltage provided by the boost circuit 4 to be large enough to drive the drive unit M1 to rotate, and by setting the boost circuit 4 to provide a stable high voltage output when the power supply voltage is unstable, the device can operate stably. Since the voltage is increased, the current is smaller, and the loss during transmission is smaller, which saves energy and improves the transmission efficiency. In this embodiment, the 5V input voltage is boosted to 9V to provide 9V voltage to the drive unit M1, so as to obtain enough power to maintain the fan rotation.

[0041] like Figure 5 As shown, in order to protect the drive unit M1, prevent the drive unit M1 from being over-voltaged or damaged, and improve the service life of the drive unit M1, a voltage divider protection circuit 2 is connected between the drive unit M1 and the control unit U1. The voltage divider protection circuit 2 includes a first resistor R13 and a third switch Q3. The drain D of the third switch Q3 is connected to the drive unit M1, the gate G is connected to the pin FAN2 of the control unit U1, and the source S is connected to the first resistor R13. The other end of the first resistor R13 is grounded, and the pin DET2 of the control unit U1 is also connected to the resistor R13.

[0042] In operation, the control unit U1 sends a high-level signal to pin FAN2 to turn on the third switch Q3, enabling the normal operation of the drive unit M1. When pin DET2 of the control unit U1 detects that the voltage across resistor R13 is higher than a set threshold, the control unit U1 sends a low-level signal to pin FAN2 to turn off the third switch Q3 and stop the drive unit M1 from working. The drive unit M1 is also protected by the voltage divider protection circuit 2. Pin DET2 determines whether the voltage detected by resistor R13 is abnormal, such as overvoltage or undervoltage, and controls the switching of the third switch Q3 to protect the drive circuit M1. When resistor R13... When the voltage drop across the two ends exceeds a certain value, pin DET2 will trigger overvoltage protection, controlling the third switch Q3 to turn off, cutting off the power supply to drive unit M1, and preventing the motor from being damaged by overvoltage; when the voltage across resistor R13 drops below a certain value, pin DET2 signal will trigger undervoltage protection, controlling the third switch Q3 to turn off, cutting off the power supply to drive unit M1, and preventing drive unit M1 from operating under voltage.

[0043] Furthermore, the voltage divider protection circuit 2 also includes a resistor R14. One end of the resistor R14 is connected to the pin DET2, and the other end is connected to the resistor R13. By setting the resistor R14, the current flowing through the third switching transistor Q3 is limited to prevent excessive current from burning out the third switching transistor Q3. The third switching transistor Q3 is an NMOSFET.

[0044] A diode D6 is provided between pin DET2 of the control unit U1 and the output terminal of the voltage regulator U3. The input terminal of the diode D6 is connected to pin DET2. By setting the diode D6, a current path is provided. When an overvoltage surge occurs, the diode D6 conducts, clamping the voltage at point DET2 to about 4V, so that the reverse electromotive force generated by motor M1 can be safely released. This keeps the voltage across M1 within a safe range, preventing excessive voltage from damaging the third switching transistor Q3 in the circuit.

[0045] Preferably, the voltage divider protection circuit 2 further includes a capacitor C7, which is connected between the stepped-down power supply 3.3V and ground to filter out high-frequency noise, provide a stable power supply voltage, and further stabilize the voltage at point DET2.

[0046] Furthermore, it also includes a 3D3 diode, specifically a 1N5819 Schottky diode. The anode of the 3D3 diode is connected to the drain D of the third switching transistor Q3, and the cathode is connected to the input voltage. In use, by designing the 3D3 diode, specifically, when the load connected in the circuit, such as the control unit M1, is de-energized, a reverse electromotive force may be generated due to the inductive characteristics. This reverse electromotive force may damage the third switching transistor Q3 in the circuit. The 3D3 diode can provide a discharge path for the reverse electromotive force, clamping the reverse electromotive force to a lower level, thereby protecting other components in the circuit from reverse voltage surges.

[0047] Furthermore, such as Figure 6 As shown, since the control unit U1 is a logic circuit, it needs to be stepped down to optimize power consumption and compatibility, while the drive unit M1 requires high voltage to obtain sufficient power. A voltage regulator U3 is provided between the output terminal of the charging interface USB1 and the control unit U1. The voltage regulator U3 is model XC6206P332MR, which steps down the 5V input from USB1 or the 9V after passing through the boost circuit 4 to 3.3V to power the control unit U1 and other logic circuits, so that the input voltage of the control unit U1 is stabilized at 3.3V.

[0048] Specifically, such as Figure 7 As shown, in order for users to adjust the fan speed according to actual needs during use, reduce fan energy consumption, thereby saving energy and extending battery life, a speed control circuit 5 is provided between the boost circuit 4 and the drive unit M1. The speed control circuit 5 includes resistors R10, R11, R12 and R21 connected in series. The output terminal of resistor R21 is grounded. The speed control circuit 5 also includes a fourth switch Q4. The drain D of the fourth switch Q4 is connected to the output terminal of resistor R10, the source S is grounded, and the gate G is connected to pin P14 of the control unit U1. The speed control circuit 5 also includes a fifth switch Q5. The drain D of the fifth switch Q5 is connected to the output terminal of resistor R12, the source S is grounded, and the gate G is connected to pin P16 of the control unit U1.

[0049] Furthermore, both the fourth switch Q4 and the fifth switch Q5 are NMOSFETs.

[0050] It should be noted that the NMOSEFT transistor is turned on when the gate voltage (G) of the NMOSFET is higher than the source voltage (S), and is turned off when the gate voltage (G) of the NMOSFET is lower than the source voltage (S).

[0051] like Figure 8As shown, during use, when pin P14 of control unit U1 outputs a high level and pin P16 outputs a low level, it is the first level of wind speed. The fourth switch Q4 is turned on and the fifth switch Q5 is turned off. Therefore, the boosted voltage of 9V passes through resistors R10 and R11 and then reaches the fourth switch Q4, and finally reaches the drive unit M1 to drive the drive unit M1 to rotate. Since only resistors R10 and R11 flow through, the voltage is relatively small and the rotation speed is slow.

[0052] like Figure 9 As shown, when pin P14 of control unit U1 outputs a low level and pin P16 outputs a high level, the fifth switch Q5 is turned on and the fourth switch Q4 is turned off, resulting in a secondary wind speed. The boosted voltage of 9V passes through resistors R10, R11, and R12 and then reaches the fifth switch Q5, finally reaching the drive unit M1 to drive the drive unit M1 to rotate. Because the voltage flows through resistors R10, R11, and R12, the voltage is larger and the rotation speed is faster. The primary wind speed is slower than the secondary wind speed.

[0053] like Figure 10 As shown, when both pins P14 and P16 of the control unit U1 are low, the fan speed is at level three. Since the fourth switch Q4 and the fifth switch Q5 are both NMOSFETs, they are both cut off when the gate G input is low. Therefore, the boosted voltage of 9V passes through resistors R10, R11, R12, and R21, and then reaches the drive unit M1, finally grounding to form a loop. Because the resistance is the largest, the voltage is the highest, and the speed of the drive unit M1 is the fastest at this time. Therefore, by setting the fourth switch Q4 and the fifth switch Q5, the speed of the drive unit M1 can be controlled by the level output of the control unit U1, thereby achieving three speed levels. Users can adjust the airflow according to their actual needs.

[0054] Furthermore, such as Figure 11 As shown, it also includes a button SW1, used to trigger a control signal. Functional control is achieved by changing the level of the KEY pin of the control unit U1. Pressing button SW1 adjusts the fan speed. In use, when the operator presses button SW1, the control unit U1 detects the input signal and starts outputting a level signal to control the conduction and cutoff of the fourth switch Q4 and the fifth switch Q5.

[0055] Specifically, such as Figure 12As shown, to make the fan convenient for users to carry around and applicable to various occasions, the drive unit M1 can rotate and output air even without an external power supply. A charging circuit 1 is provided between the charging interface USB1 and the boost circuit 4. The charging circuit 1 includes a battery BAT1 and a first switching transistor Q1. The drain D of the first switching transistor Q1 is connected to the battery BAT1, and the source S and gate G are respectively connected to the output terminal of the charging interface USB1. When the battery BAT1 outputs a high level, the first switching transistor Q1 is turned on, and the battery BAT1 can supply power to the drive unit M1; when the battery BAT1 outputs a low level, the first switching transistor Q1 is turned off, and the battery BAT1 cannot supply power to the drive unit M1. This setting can prevent the battery BAT1 from consuming energy, further protect the battery BAT1, and achieve energy saving and multi-level power supply. The rotation of the drive unit M1 can be powered by the battery BAT1 without the need for an external power supply.

[0056] Furthermore, it also includes a diode D1, which is connected to the source S and drain D of the first switching transistor Q1 respectively. By setting the diode D1 to place the reverse current, the first switching transistor Q1 is protected against reverse connection.

[0057] Furthermore, the charging circuit 1 also includes a charging chip U2. The output terminal of the charging interface USB1 is connected to the VCC pin of the charging chip U2. The BAT pin of the charging chip U2 is connected to the battery BAT1 to supply power to the battery BAT1. In this embodiment, the battery BAT1 is a lithium-ion battery. The model of the charging chip U2 is TP4056.

[0058] Furthermore, it also includes fuse F2, one end of which is connected to the input power supply -5V, and the other end is connected to the VCC pin of the charging chip U2. The rated current of fuse F2 is 2A and the rated voltage is 6V, thereby realizing overcurrent protection for the charging chip U2.

[0059] Furthermore, it also includes a charging indicator LED1, the anode of which is connected to the output terminal of the control unit U1, and is used to control the charging indicator LED1 to turn on or off by changing the level of the input control unit U1.

[0060] Furthermore, such as Figure 13As shown, the charging chip U2 also includes pin CHRG and pin STDBY, which are used to indicate the charging status. In this embodiment, when charging is in progress, pin CHRG of the charging chip U2 outputs a low level, lighting up the charging indicator LED1. When charging is complete, pin CHRG outputs a high level, and the charging indicator LED1 turns off.

[0061] Preferably, the charging chip U2 further includes a pin PROG, and the external resistor R3 connected to the pin PROG sets the charging current.

[0062] Preferably, the charging chip U2 includes a TEMP pin, which is connected to the temperature detection resistor R7 of the battery BAT1 to monitor the temperature of the battery BAT1 and ensure the safety of the charging process.

[0063] Specifically, such as Figure 14 As shown, a detection circuit 3 is provided between the control unit U1 and the charging chip U2. One end of the detection circuit 3 is connected to the control unit U1, and the other end is connected to the CE pin of the charging chip U2. The detection circuit 3 includes a second switch Q2. The gate G of the second switch Q2 is connected to the CE pin, the drain D is connected to the control unit U1, and the source S is grounded. When the CE pin of the charging chip U2 outputs a high level, the second switch Q2 is turned on. The CHK pin of the control unit U1 is connected to the drain D of the second switch Q2. When a high-level signal is received, the battery BAT1 is detected to be fully charged. At this time, the charging indicator LED1 is constantly lit. When the CE pin of the charging chip U2 outputs a low level, the second switch Q2 is turned off. The CHK pin of the control unit U1 is connected to the drain D of the second switch Q2. When a low-level signal is received, the battery BAT1 is detected to be charging. At this time, the charging indicator LED1 flashes.

[0064] The following is a detailed explanation of the working principle of this utility model;

[0065] The charging interface USB1 supplies power to the drive unit M1 and the control unit U1, while the control unit U1 controls the start and stop of the drive unit M1. A boost circuit 4 is connected between the charging interface USB1 and the drive unit M1 to provide a 9V voltage to the drive unit M1, obtaining sufficient power to maintain fan rotation. The pin DET2 determines whether the voltage detected by the resistor R13 is abnormal, such as overvoltage or undervoltage, thereby controlling the third switch Q3 to turn on and off to protect the drive circuit M1. A speed control circuit 5 is provided between the boost circuit 4 and the drive unit M1, which controls the speed of the drive unit M1 by controlling the level output of the control unit U1, realizing three speed levels. Users can adjust the airflow according to actual needs. A charging circuit 1 is provided between the charging interface USB1 and the boost circuit 4. The charging circuit 1 includes a battery BAT1 and a first switch Q1. When the first switch Q1 is turned on, the battery BAT1 can supply power to the drive unit M1, realizing multi-level power supply. The drive unit M1 can also rotate and output air without an external power source.

[0066] The innovation of this utility model lies in achieving speed regulation by generating signals through the control unit, and significantly improving safety, energy efficiency and control flexibility by combining a voltage divider protection circuit and an optimized voltage conversion module; a multi-level protection system is formed by setting voltage divider detection and temperature monitoring; the boost and buck circuits work independently to meet the high power requirements of the motor and the low power consumption requirements of the logic circuit respectively, thereby improving overall energy efficiency.

[0067] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style of the specification is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other implementations that can be understood by those skilled in the art.

[0068] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A fan control circuit, characterized by, It includes charging interface (USB1), drive unit (M1) and control unit (U1), the input end of drive unit (M1) is connected with charging interface (USB1), the output end is connected with control unit (U1), charging interface (USB1) is the power supply for drive unit (M1) and control unit (U1), control unit (U1) controls the start-stop of drive unit (M1); Wherein, the drive unit (M1) and the control unit (U1) are connected with the voltage division protection circuit (2), the voltage division protection circuit (2) includes the first resistance R13 and the third switch tube (Q3), the drain (D) of the third switch tube (Q3) is connected with the drive unit (M1), the gate (G) is connected with the pin (FAN2) of the control unit (U1), the source (S) is connected with the first resistance (R13), the other end of the first resistance (R13) is grounded, and the pin (DET2) of the control unit (U1) is also connected with the resistance (R13); The control unit (U1) sends high level signal to pin (FAN2) to make the third switch tube (Q3) conduct, to realize the normal work of drive unit (M1); When the pin (DET2) of the control unit (U1) detects that the voltage of the upper end of the resistance (R13) is higher than the set threshold, the control unit (U1) sends low level signal to pin (FAN2) to make the third switch tube (Q3) cut off, and makes drive unit (M1) stop working.

2. The fan control circuit of claim 1, wherein, The voltage division protection circuit (2) further includes resistance (R14), one end of the resistance (R14) is connected with pin (DET2), the other end is connected with resistance (R13), and the third switch tube (Q3) is NMOSFET tube.

3. The fan control circuit of claim 2, wherein, The output end of the charging interface (USB1) is provided with voltage stabilizer (U3) between the control unit (U1), to make the input voltage of the control unit (U1) stable at 3.3V.

4. The fan control circuit of claim 3, wherein, The pin (DET2) of the control unit (U1) is provided with diode six (D6) between the output end of the voltage stabilizer (U3), and the input end of the diode six (D6) is connected with the pin (DET2).

5. The fan control circuit of claim 1, wherein, The charging interface (USB1) is connected with boost circuit (4) between the drive unit (M1), and the boost circuit (4) includes inductance (L1), control chip (U4) and capacitor (C2).

6. The fan control circuit of claim 5, wherein, The boost circuit (4) is provided with speed regulation circuit (5) between the drive unit (M1), and the speed regulation circuit (5) includes resistance (R10), resistance (R11), resistance (R12) and resistance (R21) arranged in series, and the output end of the resistance (R21) is grounded.

7. The fan control circuit of claim 6, wherein, The speed regulation circuit (5) further includes fourth switch tube (Q4), the drain (D) of the fourth switch tube (Q4) is connected with the output end of the resistance (R10), the source (S) is grounded, and the gate (G) is connected with the pin (P14) of the control unit (U1).

8. The fan control circuit of claim 7, wherein, The speed regulation circuit (5) further comprises a fifth switch tube (Q5), the drain (D) of the fifth switch tube (Q5) is connected with the output end of the resistor (R12), the source (S) is grounded, and the gate (G) is connected with the pin (P16) of the control unit (U1).

9. The fan control circuit of claim 5, wherein, A charging circuit (1) is arranged between the charging interface (USB1) and the voltage boosting circuit (4), the charging circuit (1) comprises a battery (BAT1) and a first switch tube (Q1), the drain (D) of the first switch tube (Q1) is connected with the battery (BAT1), and the source (S) and the gate (G) are respectively connected with the output end of the charging interface (USB1).

10. The fan control circuit of claim 9, wherein, The charging circuit (1) further comprises a charging chip (U2), the output end of the charging interface (USB1) is connected with the pin (VCC) of the charging chip (U2), and the pin (BAT) of the charging chip (U2) is connected with the battery (BAT1).

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