Low-voltage fan control circuit

Abstract

The utility model belongs to the technical field of fans, and particularly relates to a low-voltage fan control circuit. A master control circuit is respectively connected with a low-power-consumption control circuit and a display circuit, the low-power-consumption control circuit is connected with a motor driving control circuit, and the display circuit is respectively connected with a switch circuit and a buzzer circuit. The main control circuit, the low-power-consumption control circuit and the motor driving control circuit are all powered by the battery management circuit, and after circuit voltage reduction, the USB port outputs voltage for power supply. According to the utility model, the motor is controlled to drive the fan to rotate under the power supply condition of a power adapter and solar energy.

Description

Technical Field

[0001] The utility model belongs to the technical field of fans, and particularly relates to a low-voltage fan control circuit. Background Art

[0002] Existing fans generally have a single function and limited usage environments. They cannot be used in areas with insufficient power supply during summer. However, fans are essential in summer, so there is a problem of incompatibility with the environment during user use. Moreover, the driving scheme of fan motors generally samples with sensor drive, which not only has a high cost, but also has low motor operating efficiency and large electromagnetic noise.

[0003] The utility model has the function of outdoor use, and at the same time can be compatible with solar power input, which is convenient to use and reduces energy loss and pollution; through sensorless magnetic field orientation control, the circuit cost is reduced, and at the same time, the fan is ensured to operate stably and efficiently; it has a USB output 5V voltage interface, which can meet the use of some peripheral electronic devices. Summary of the Utility Model

[0004] The utility model provides a low-voltage fan control circuit to enable the fan in low-voltage areas to be used normally, with high motor operating efficiency and no electromagnetic noise.

[0005] The utility model is realized through the following technical solutions:

[0006] A low-voltage fan control circuit, the control circuit includes a main control circuit, the main control circuit is respectively connected to a low-power consumption control circuit and a display circuit, the low-power consumption control circuit is connected to a motor drive control circuit, and the display circuit is respectively connected to a switch circuit and a buzzer circuit;

[0007] The main control circuit, the low-power consumption control circuit and the motor drive control circuit are all powered by a battery management circuit, and after the circuit voltage is stepped down, the USB port outputs voltage for power supply.

[0008] Further, the main control circuit includes a chip U2, one end of the 1st terminal of the chip U2 is respectively connected to one end of a capacitor C6, one end of a capacitor C5 and the voltage AVDD terminal, and the other end of the capacitor C6 and the other end of the capacitor C5 are connected to the 1st terminal of the chip U2 and then grounded;

[0009] The 3rd terminal of the chip U2 is respectively connected to one end of a capacitor C22 and one end of a resistor R24, the other end of the capacitor C22 is connected to one end of a capacitor C8 and then grounded, the other end of the capacitor C8 is connected to the 4th terminal of the chip U2, the other end of the resistor R24 is connected to the 2nd terminal of a chip U3 of the display circuit, and the 16th terminal of the chip U2 is grounded in series with a capacitor C7.

[0010] Further, the display circuit includes a chip U3. The 3rd terminal of the chip U3 is connected to one end of a capacitor C26. The other end of the capacitor C22 is connected to the 1st terminal of the chip U3 and then grounded. The 4th terminal of the chip U3 is connected to a USB output voltage circuit. The 7th terminal of the chip U3 is connected to a low-power control circuit. The 8th terminal of the chip U3 is connected in series with a resistor R29 and then connected to a 5V voltage. The 9th terminal of the chip U3 is connected to a battery management circuit. The 10th terminal of the chip U3 is connected to the SW1 terminal of a switch circuit. The 12th terminal of the chip U3 is connected to the SW2 terminal of the switch circuit. The 13th terminal of the chip U3 is connected to the SW3 terminal of the switch circuit;

[0011] The 11th terminal of the chip U3 is connected to a buzzer circuit;

[0012] The 14th terminal of the chip U3 is connected to one end of a resistor R19. The other end of the resistor R19 is connected to the 1st terminal of an SMG. The 16th terminal of the chip U3 is connected to one end of a resistor R20. The other end of the resistor R20 is connected to the 2nd terminal of the SMG. The 17th terminal of the chip U3 is connected to one end of a resistor R21. The other end of the resistor R21 is connected to the 3rd terminal of the SMG. The 18th terminal of the chip U3 is connected to one end of a resistor R22. The other end of the resistor R22 is connected to the 4th terminal of the SMG. The 19th terminal of the chip U3 is connected to one end of a resistor R23. The other end of the resistor R23 is connected to the 5th terminal of the SMG.

[0013] Further, the buzzer circuit includes a triode Q3. The 1st terminal of the triode Q3 is connected in series with a resistor R34 and then connected to the 11th terminal of the chip U3. The 2nd terminal of the triode Q3 is connected in series with a resistor R35 and then connected to one end of a buzzer. The other end of the buzzer is connected to a 5V voltage;

[0014] The 3rd terminal of the triode Q3 is grounded.

[0015] Further, the low-power control circuit includes a resistor R17. One end of the resistor R17 is connected to the 7th terminal of the chip U3. The other end of the resistor R17 is respectively connected to one end of a resistor R18 and the 2nd terminal of a field-effect transistor Q2A. The 7th and 8th terminals of the field-effect transistor Q2A are both connected to one end of a resistor R16. The other end of the resistor R16 is respectively connected to one end of a resistor R15 and the 4th terminal of a field-effect transistor Q2B. The 3rd terminal of the field-effect transistor Q2A is respectively connected to the other end of the resistor R15, a voltage of 12V, and one end of a capacitor C18. The other end of the capacitor C18 is grounded. The 5th and 5th terminals of the field-effect transistor Q2A are both connected to a voltage of 12V and one end of a capacitor CE3. The other end of the capacitor CE3 is respectively connected to the 1st terminal of the field-effect transistor Q2A and the other end of the resistor R18 and then grounded.

[0016] Further, the motor drive control circuit includes a motor drive chip M1, a motor drive chip M2, and a motor drive chip M3. The 4th terminal of the motor drive chip M1 is respectively connected to one end of a capacitor C12 and one end of a resistor R10. The other end of the resistor R10 is connected to the 5th terminal of the chip U2. The 3rd terminal of the motor drive chip M1 is respectively connected to the other end of the capacitor C12 and one end of a capacitor C9. The other end of the capacitor C9 is grounded;

[0017] The 2nd terminal of the motor drive chip M1 is respectively connected to one end of a capacitor C13 and one end of a resistor R9. The other end of the resistor R9 is connected to the 6th terminal of the chip U2. The 1st terminal of the motor drive chip M1 is respectively connected to the other end of the capacitor C13, one end of a resistor RB1, one end of a capacitor C10, and the 13th terminal of the chip U2;

[0018] The 5th terminal, the 6th terminal, the 7th terminal, and the 8th terminal of the motor drive chip M1 are all connected to the 1st terminal of the stator MOTO;

[0019] The 4th terminal of the motor drive chip M2 is respectively connected to one end of a capacitor C14 and one end of a resistor R12. The other end of the resistor R12 is connected to the 7th terminal of the chip U2. The 3rd terminal of the motor drive chip M2 is respectively connected to the other end of the capacitor C14 and a voltage of 12V-1;

[0020] The 2nd terminal of the motor drive chip M2 is respectively connected to one end of a capacitor C15 and one end of a resistor R11. The other end of the resistor R11 is connected to the 8th terminal of the chip U2. The 1st terminal of the motor drive chip M2 is respectively connected to the other end of the capacitor C15, one end of a resistor RB2, one end of a capacitor C11, and the 11th terminal of the chip U2;

[0021] The 5th terminal, 6th terminal, 7th terminal, and 8th terminal of the motor drive chip M2 are all connected to the 2nd terminal of the stator MOTO;

[0022] The 4th terminal of the motor drive chip M3 is respectively connected to one end of the capacitor C16 and one end of the resistor R14. The other end of the resistor R14 is connected to the 9th terminal of the chip U2. The 3rd terminal of the motor drive chip M3 is respectively connected to the other end of the capacitor C16 and the voltage 12V-1;

[0023] The 2nd terminal of the motor drive chip M3 is respectively connected to one end of the capacitor C17 and one end of the resistor R13. The other end of the resistor R13 is connected to the 10th terminal of the chip U2. The 1st terminal of the motor drive chip M3 is respectively connected to the other end of the capacitor C17, the other end of the resistor RB2, the other end of the capacitor C11, the other end of the resistor RB1, the other end of the capacitor C10, the 12th terminal of the chip U2, and one end of the resistor RB3. One end of the resistor RB3 is grounded;

[0024] The 5th terminal, 6th terminal, 7th terminal, and 8th terminal of the motor drive chip M3 are all connected to the 2nd terminal of the stator MOTO.

[0025] Furthermore, the battery management circuit provides a 12V voltage. The battery management circuit reduces the 12V voltage to 5V through a buck circuit, and the 5V is then output through a USB output voltage circuit.

[0026] Furthermore, the main control circuit is also equipped with a programming port.

[0027] The beneficial effects of the present utility model are as follows:

[0028] The present utility model is convenient to operate. The fan speed gears and battery power are clearly displayed. The circuit integration degree is high, reducing the circuit cost. It has multiple protections, is safe and reliable, has a low-power standby mode, reducing power consumption, extending the battery usage time, and can be used outdoors or in a pure battery-powered mode.

[0029] The present utility model can not only use ordinary power supplies but also use solar clean energy.

[0030] The present utility model can prevent safety hazards caused by excessive current. Description of the Drawings

[0031] Figure 1 It is the circuit block diagram of the present utility model.

[0032] Figure 2It is the USB output voltage circuit diagram of the present utility model, where (a) is the USB interface circuit and (b) is the USB step-down circuit.

[0033] Figure 3 It is the low-power consumption control circuit diagram of the present utility model.

[0034] Figure 4 It is the battery management circuit diagram of the present utility model.

[0035] Figure 5 It is the motor drive control circuit diagram of the present utility model.

[0036] Figure 6 It is the buzzer circuit diagram of the present utility model.

[0037] Figure 7 It is the step-down circuit diagram of the present utility model.

[0038] Figure 8 It is the switch circuit diagram of the present utility model.

[0039] Figure 9 It is the programming port diagram of the present utility model.

[0040] Figure 10 It is the display circuit diagram of the present utility model.

[0041] Figure 11 It is the main control circuit diagram of the present utility model. Detailed implementation manners

[0042] In the following description, for the purpose of illustration rather than limitation, specific details such as specific system architectures, technologies, etc. are proposed to thoroughly understand the embodiments of the present application. However, those skilled in the art should clearly understand that the present application can also be implemented in other embodiments without these specific details. In other cases, the detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid unnecessary details from interfering with the description of the present application.

[0043] It should be understood that when used in this specification and the appended claims, the term "comprising" indicates the presence of the described features, wholes, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their combinations.

[0044] It should also be understood that the terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the specification of the present application and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" are intended to include the plural forms.

[0045] The following clearly and completely describes the technical solutions in the embodiments of the present application with reference to the accompanying drawings of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0046] Many specific details are set forth in the following description to facilitate a thorough understanding of the present application, but the present application may be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the connotation of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0047] According to Figure 1 As shown, a low-voltage fan control circuit, the control circuit includes a main control circuit, the main control circuit is respectively connected to a low-power consumption control circuit and a display circuit, the low-power consumption control circuit is connected to a motor drive control circuit, and the display circuit is respectively connected to a switch circuit and a buzzer circuit;

[0048] The main control circuit, the low-power consumption control circuit and the motor drive control circuit are all powered by a battery management circuit. After the circuit is stepped down, the USB port outputs voltage for power supply. The voltage output by the USB port is mainly used for external low-voltage charging, such as power banks, mobile phones, table lamps, etc.

[0049] Further, the main control circuit includes a chip U2. One end of the 1st terminal of the chip U2 is respectively connected to one end of a capacitor C6, one end of a capacitor C5 and the voltage AVDD terminal. The other end of the capacitor C6 and the other end of the capacitor C5 are connected to the 1st terminal of the chip U2 and then grounded;

[0050] The 3rd terminal of the chip U2 is respectively connected to one end of a capacitor C22 and one end of a resistor R24. The other end of the capacitor C22 is connected to one end of a capacitor C8 and then grounded. The other end of the capacitor C8 is connected to the 4th terminal of the chip U2. The other end of the resistor R24 is connected to the 2nd terminal of the chip U3 of the display circuit. The 16th terminal of the chip U2 is grounded in series with a capacitor C7.

[0051] Specifically, the chip U2 reconstructs the motor state by collecting signals such as the motor bus voltage and phase current, estimates the current position of the motor rotor magnetic field, and controls the amplitude and frequency of the output stator voltage through the output signal to achieve accurate control of the motor operation. The sampling sensorless field-oriented control (FOC) method is adopted. This control circuit has the advantages of high operating efficiency, low noise, and stable output torque. The motor control has multiple protection functions: hardware overcurrent protection, software overcurrent protection, sampling error protection, undervoltage protection, overvoltage protection, open-phase protection, stall protection, start-up protection, monitoring protection of the maximum and minimum speeds, and maximum output power limit protection. The control of the motor rotation direction is achieved by controlling the direction of the conduction current of the stator U, V, and W phases.

[0052] Further, the display circuit includes the chip U3. The 3rd terminal of the chip U3 is connected to one end of the capacitor C26. The other end of the capacitor C22 is connected to the 1st terminal of the chip U3 and then grounded. The 4th terminal of the chip U3 is connected to the USB output voltage circuit. The 7th terminal of the chip U3 is connected to the low-power control circuit. The 8th terminal of the chip U3 is connected in series with the resistor R29 and then connected to the 5V voltage. The 9th terminal of the chip U3 is connected to the battery management circuit. The 10th terminal of the chip U3 is connected to the SW1 terminal of the switch circuit. The 12th terminal of the chip U3 is connected to the SW2 terminal of the switch circuit. The 13th terminal of the chip U3 is connected to the SW3 terminal of the switch circuit.

[0053] The 11th terminal of the chip U3 is connected to the buzzer circuit.

[0054] The 14th terminal of the chip U3 is connected to one end of the resistor R19. The other end of the resistor R19 is connected to the 1st terminal of the SMG. The 16th terminal of the chip U3 is connected to one end of the resistor R20. The other end of the resistor R20 is connected to the 2nd terminal of the SMG. The 17th terminal of the chip U3 is connected to one end of the resistor R21. The other end of the resistor R21 is connected to the 3rd terminal of the SMG. The 18th terminal of the chip U3 is connected to one end of the resistor R22. The other end of the resistor R22 is connected to the 4th terminal of the SMG. The 19th terminal of the chip U3 is connected to one end of the resistor R23. The other end of the resistor R23 is connected to the 5th terminal of the SMG.

[0055] Specifically, the chip U3 realizes precise control of battery charging by detecting DCIN_ADC and BAT_ADC; the chip U3 identifies the change in the level of the SW3 button, sends an instruction signal to the motor drive main control chip U2, and the chip U2 realizes the turning on and off of the fan according to the received instruction signal; the chip U3 identifies the changes in the levels of SW1 and SW2, sends corresponding instructions to the main control chip U2, and realizes the control of the fan speed; the chip U3 simultaneously outputs corresponding signals to the digital tube SMG to display the corresponding fan speed and battery power.

[0056] Further, the buzzer circuit includes a triode Q3. The 1st terminal of the triode Q3 is connected to the 11th terminal of the chip U3 after being connected in series with the resistor R34. The 2nd terminal of the triode Q3 is connected to one end of the buzzer after being connected in series with the resistor R35. The other end of the buzzer is connected to the 5V voltage.

[0057] The 3rd terminal of the triode Q3 is grounded.

[0058] Further, the low-power consumption control circuit includes a resistor R17. One end of the resistor R17 is connected to the 7th terminal of the chip U3. The other end of the resistor R17 is respectively connected to one end of the resistor R18 and the 2nd terminal of the field effect transistor Q2A. The 7th and 8th terminals of the field effect transistor Q2A are both connected to one end of the resistor R16. The other end of the resistor R16 is respectively connected to one end of the resistor R15 and the 4th terminal of the field effect transistor Q2B. The 3rd terminal of the field effect transistor Q2A is respectively connected to the other end of the resistor R15, the 12V voltage, and one end of the capacitor C18. The other end of the capacitor C18 is grounded. The 5th and 6th terminals of the field effect transistor Q2A are both connected to the 12V voltage and one end of the capacitor CE3. The other end of the capacitor CE3 is respectively connected to the 1st terminal of the field effect transistor Q2A and the other end of the resistor R18 and then grounded.

[0059] Specifically, during standby, the chip U3 outputs a control signal to control the MOS Q2B to disconnect, cutting off the current of the motor drive main control and control circuits to reduce current consumption and extend the battery usage time.

[0060] Further, the motor drive control circuit includes a motor drive chip M1, a motor drive chip M2, and a motor drive chip M3. The 4th terminal of the motor drive chip M1 is respectively connected to one end of the capacitor C12 and one end of the resistor R10. The other end of the resistor R10 is connected to the 5th terminal of the chip U2. The 3rd terminal of the motor drive chip M1 is respectively connected to the other end of the capacitor C12 and one end of the capacitor C9. The other end of the capacitor C9 is grounded.

[0061] The second terminal of the motor drive chip M1 is respectively connected to one end of the capacitor C13 and one end of the resistor R9. The other end of the resistor R9 is connected to the sixth terminal of the chip U2. The first terminal of the motor drive chip M1 is respectively connected to the other end of the capacitor C13, one end of the resistor RB1, one end of the capacitor C10, and the thirteenth terminal of the chip U2;

[0062] The fifth terminal, the sixth terminal, the seventh terminal, and the eighth terminal of the motor drive chip M1 are all connected to the first terminal of the stator MOTO;

[0063] The fourth terminal of the motor drive chip M2 is respectively connected to one end of the capacitor C14 and one end of the resistor R12. The other end of the resistor R12 is connected to the seventh terminal of the chip U2. The third terminal of the motor drive chip M2 is respectively connected to the other end of the capacitor C14 and the voltage 12V-1;

[0064] The second terminal of the motor drive chip M2 is respectively connected to one end of the capacitor C15 and one end of the resistor R11. The other end of the resistor R11 is connected to the eighth terminal of the chip U2. The first terminal of the motor drive chip M2 is respectively connected to the other end of the capacitor C15, one end of the resistor RB2, one end of the capacitor C11, and the eleventh terminal of the chip U2;

[0065] The fifth terminal, the sixth terminal, the seventh terminal, and the eighth terminal of the motor drive chip M2 are all connected to the second terminal of the stator MOTO;

[0066] The fourth terminal of the motor drive chip M3 is respectively connected to one end of the capacitor C16 and one end of the resistor R14. The other end of the resistor R14 is connected to the ninth terminal of the chip U2. The third terminal of the motor drive chip M3 is respectively connected to the other end of the capacitor C16 and the voltage 12V-1;

[0067] The second terminal of the motor drive chip M3 is respectively connected to one end of the capacitor C17 and one end of the resistor R13. The other end of the resistor R13 is connected to the tenth terminal of the chip U2. The first terminal of the motor drive chip M3 is respectively connected to the other end of the capacitor C17, the other end of the resistor RB2, the other end of the capacitor C11, the other end of the resistor RB1, the other end of the capacitor C10, the twelfth terminal of the chip U2, and one end of the resistor RB3. One end of the resistor RB3 is grounded;

[0068] The fifth terminal, the sixth terminal, the seventh terminal, and the eighth terminal of the motor drive chip M3 are all connected to the second terminal of the stator MOTO.

[0069] Furthermore, the battery management circuit provides a 12V voltage, and the battery management circuit reduces the 12V voltage to 5V through a step-down circuit, and the 5V is output through a USB output voltage circuit.

[0070] Furthermore, the main control circuit is also equipped with a burning port.

[0071] Furthermore, the output voltage of the solar panel or 13.5V power adapter of the battery management circuit is connected to the charging circuit through the DC_IN port, and the stable output voltage of 12V can be achieved through the precise control of the chip U1. This voltage is input to the battery port BAT to charge the battery;

[0072] Chip U1 detects the current battery voltage through the FB pin. When it is lower than the set threshold, it starts charging the battery. When the high voltage threshold is reached, it shuts off charging.

[0073] Chip U1 can limit the charging current through the voltage of the CSP pin to prevent safety hazards caused by excessive current.

[0074] Furthermore, the chip U4 of the USB output voltage circuit reduces the 12V voltage to 5V through the DC-DC BUCK, and has an output current capacity of 1A. This port can supply power to devices with an operating voltage of 5V, such as charging a mobile phone.

[0075] The utility model has the function of outdoor use and is compatible with solar power generation input. It is easy to use and reduces energy loss and pollution. Through non-inductive magnetic field directional control, the circuit cost is reduced while ensuring stable and efficient operation of the fan. It has a USB output 5V voltage interface to meet the use of some peripheral electronic equipment.

[0076] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A low voltage fan control circuit, characterized in that: The control circuit includes a main control circuit, the main control circuit is connected to the low power consumption control circuit, the switch circuit, the buzzer and the display circuit respectively, and the low power consumption control circuit is connected to the motor drive control circuit; The main control circuit, low power consumption control circuit and motor drive control circuit are all powered by a battery management circuit. After the power supply of the battery management circuit is stepped down by the circuit, the USB port outputs the voltage for power supply.

2. A low voltage fan control circuit according to claim 1, characterized in that: The main control circuit includes a chip U2, and terminal 1 of the chip U2 is respectively connected to one end of a capacitor C6, one end of a capacitor C5 and a voltage AVDD terminal, and the other end of the capacitor C6 and the other end of the capacitor C5 are connected to terminal 1 of the chip U2 and then grounded; Terminal 3 of the chip U2 is respectively connected to one end of the capacitor C22 and one end of the resistor R24, the other end of the capacitor C22 is connected to one end of the capacitor C8 and then grounded, the other end of the capacitor C8 is connected to terminal 4 of the chip U2, the other end of the resistor R24 ​​is connected to terminal 2 of the chip U3 of the display circuit, and terminal 16 of the chip U2 is connected in series with the capacitor C7 and then grounded.

3. A low voltage fan control circuit according to claim 2, characterized in that: The display circuit includes a chip U3, a terminal 3 of the chip U3 is connected to one end of a capacitor C26, the other end of the capacitor C22 is connected to a terminal 1 of the chip U3 and then grounded, a terminal 4 of the chip U3 is connected to a USB output voltage circuit, a terminal 7 of the chip U3 is connected to a low power consumption control circuit, a terminal 8 of the chip U3 is connected in series with a resistor R29 and then connected to a 5V voltage, a terminal 9 of the chip U3 is connected to a battery management circuit, a terminal 10 of the chip U3 is connected to a terminal SW1 of a switch circuit, a terminal 12 of the chip U3 is connected to a terminal SW2 of a switch circuit, and a terminal 13 of the chip U3 is connected to a terminal SW3 of a switch circuit; Terminal 11 of the chip U3 is connected to the buzzer circuit; Terminal 14 of the chip U3 is connected to one end of the resistor R19, and the other end of the resistor R19 is connected to terminal 1 of SMG. Terminal 16 of the chip U3 is connected to one end of the resistor R20, and the other end of the resistor R20 is connected to terminal 2 of SMG. Terminal 17 of the chip U3 is connected to one end of the resistor R21, and the other end of the resistor R21 is connected to terminal 3 of SMG. Terminal 18 of the chip U3 is connected to one end of the resistor R22, and the other end of the resistor R22 is connected to terminal 4 of SMG. Terminal 19 of the chip U3 is connected to one end of the resistor R23, and the other end of the resistor R23 is connected to terminal 5 of SMG.

4. A low voltage fan control circuit according to claim 3, characterized in that: The buzzer circuit includes a transistor Q3, wherein terminal 1 of the transistor Q3 is connected in series with a resistor R34 and then connected to terminal 11 of the chip U3, terminal 2 of the transistor Q3 is connected in series with a resistor R35 and then connected to one end of the buzzer, and the other end of the buzzer is connected to a 5V voltage; Terminal 3 of the transistor Q3 is grounded.

5. A low voltage fan control circuit according to claim 3, characterized in that: The low power consumption control circuit includes a resistor R17, one end of which is connected to terminal 7 of chip U3, the other end of which is respectively connected to one end of resistor R18 and terminal 2 of field effect tube Q2A, terminals 7 and 8 of field effect tube Q2A are respectively connected to one end of resistor R16, the other end of which is respectively connected to one end of resistor R15 and terminal 4 of field effect tube Q2B, terminal 3 of field effect tube Q2A is respectively connected to the other end of resistor R15, voltage 12V and one end of capacitor C18, the other end of capacitor C18 is grounded, terminals 5 and 5 of field effect tube Q2A are respectively connected to voltage 12V and one end of capacitor CE3, the other end of capacitor CE3 is respectively connected to terminal 1 of field effect tube Q2A and the other end of resistor R18 and then grounded.

6. A low voltage fan control circuit according to claim 5, characterized in that: The motor drive control circuit includes a motor drive chip M1, a motor drive chip M2 and a motor drive chip M3, wherein terminal 4 of the motor drive chip M1 is respectively connected to one end of a capacitor C12 and one end of a resistor R10, the other end of the resistor R10 is connected to terminal 5 of the chip U2, terminal 3 of the motor drive chip M1 is respectively connected to the other end of the capacitor C12 and one end of the capacitor C9, and the other end of the capacitor C9 is grounded; Terminal 2 of the motor driving chip M1 is respectively connected to one end of the capacitor C13 and one end of the resistor R9, the other end of the resistor R9 is connected to terminal 6 of the chip U2, and terminal 1 of the motor driving chip M1 is respectively connected to the other end of the capacitor C13, one end of the resistor RB1, one end of the capacitor C10 and terminal 13 of the chip U2; Terminal 5 of the motor drive chip M1, terminal 6 of the motor drive chip M1, terminal 7 of the motor drive chip M1 and terminal 8 of the motor drive chip M1 are all connected to terminal 1 of the stator MOTO; Terminal 4 of the motor driving chip M2 is connected to one end of the capacitor C14 and one end of the resistor R12 respectively, the other end of the resistor R12 is connected to terminal 7 of the chip U2, and terminal 3 of the motor driving chip M2 is connected to the other end of the capacitor C14 and the voltage 12V-1 respectively; Terminal 2 of the motor driving chip M2 is respectively connected to one end of the capacitor C15 and one end of the resistor R11, the other end of the resistor R11 is connected to terminal 8 of the chip U2, and terminal 1 of the motor driving chip M2 is respectively connected to the other end of the capacitor C15, one end of the resistor RB2, one end of the capacitor C11 and terminal 11 of the chip U2; Terminal 5 of the motor drive chip M2, terminal 6 of the motor drive chip M2, terminal 7 of the motor drive chip M2 and terminal 8 of the motor drive chip M2 are all connected to terminal 2 of the stator MOTO; Terminal 4 of the motor driving chip M3 is connected to one end of the capacitor C16 and one end of the resistor R14 respectively, the other end of the resistor R14 is connected to terminal 9 of the chip U2, and terminal 3 of the motor driving chip M3 is connected to the other end of the capacitor C16 and the voltage 12V-1 respectively; Terminal 2 of the motor driving chip M3 is respectively connected to one end of the capacitor C17 and one end of the resistor R13, the other end of the resistor R13 is connected to terminal 10 of the chip U2, terminal 1 of the motor driving chip M3 is respectively connected to the other end of the capacitor C17, the other end of the resistor RB2, the other end of the capacitor C11, the other end of the resistor RB1, the other end of the capacitor C10, terminal 12 of the chip U2 and one end of the resistor RB3, and one end of the resistor RB3 is grounded; Terminal 5 of the motor driving chip M3, terminal 6 of the motor driving chip M3, terminal 7 of the motor driving chip M3 and terminal 8 of the motor driving chip M3 are all connected to terminal 2 of the stator MOTO.

7. A low voltage fan control circuit according to claim 3, characterized in that: The battery management circuit provides a 12V voltage, and the battery management circuit reduces the 12V voltage to 5V through a step-down circuit, and the 5V is then output through a USB output voltage circuit.

8. The low voltage fan control circuit according to claim 1, characterized in that: The main control circuit is also equipped with a burning port.

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