Portable fan, driving circuit for portable fan, and handheld fan

Abstract

A portable fan, comprising an air duct portion (10), an air blowing portion (20) and a handheld portion (30). The air duct portion comprises a body, wherein an air guide cavity (13) is provided inside the body; an air outlet (121) and an air inlet (111) are provided at two opposite ends of the air duct portion, and both the air outlet and the air inlet are in communication with the air guide cavity; and a positioning projecting column (122) is provided in the body. The air blowing portion comprises rotary blades (21) and a driving portion (22) that is in drive connection with the rotary blades, wherein the rotary blades are rotatably mounted in the air guide cavity and are arranged towards the air outlet; and the driving portion comprises a stator (221) and a rotor (222) sleeved on the outside of the stator, with the rotor being fixedly mounted on the rotary blades and being coaxially arranged with the rotary blades, and the stator being fixedly sleeved on the positioning projecting column.

Description

Portable fan, portable fan driving circuit and handheld fan Technical Field

[0001] The present application relates to the technical field of fans, and in particular to a portable fan, a driving circuit for a portable fan, and a handheld fan. Background Art

[0002] Fans are common household appliances in our daily lives, creating air circulation and dissipating heat. Portable fans are popular for their light weight and portability, requiring them to be as short and compact as possible. However, existing portable fans use motors with an increasing number of coils mounted on their stator frames, leaving them with limited internal space.

[0003] Summary of the Invention

[0004] The main purpose of the present application is to provide a portable fan, comprising: an air duct part, a blowing part and a hand-held part, wherein the air duct part comprises a main body, an air guide cavity is arranged inside the main body, an air outlet and an air inlet are arranged at opposite ends of the air duct part, the air outlet and the air inlet are both connected to the air guide cavity, and a positioning boss is arranged in the main body; the blowing part comprises a rotating fan blade and a driving part connected to the rotating fan blade, the rotating fan blade is rotatably installed in the air guide cavity and is arranged toward the air outlet; the driving part comprises a stator and a rotor sleeved outside the stator, the rotor is fixedly mounted on the rotating fan blade and is coaxially arranged with the rotating fan blade, and the stator is fixedly sleeved on the positioning boss. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] This application will illustrate the embodiments with reference to the accompanying drawings. The drawings in this application are only used to describe the embodiments for illustrative purposes. Without departing from the principles of this application, those skilled in the art can easily make other embodiments according to the steps described below by following the description.

[0006] FIG1-1 is a schematic structural diagram of a fan provided in an embodiment of the present application.

[0007] 1-2 is a schematic structural diagram of a fan with some parts removed provided in an embodiment of the present application.

[0008] 1-3 are schematic structural diagrams of a fan from another perspective provided in an embodiment of the present application.

[0009] 1-4 are cross-sectional views of the fan provided in an embodiment of the present application.

[0010] 1-5 are cross-sectional views of the fan from another perspective provided in an embodiment of the present application.

[0011] 1-6 are cross-sectional views of the fan provided in an embodiment of the present application.

[0012] 1-7 is a cross-sectional view of a fan from another perspective provided in an embodiment of the present application.

[0013] FIG2-1 is a schematic diagram of a charging and power supply circuit of a portable fan provided in an embodiment of the present application.

[0014] Figure 2-2 is a schematic diagram of a fan driving circuit of a portable fan provided in an embodiment of the present application.

[0015] 2-3 are schematic diagrams of the main control circuit of the portable fan provided in an embodiment of the present application.

[0016] FIG3-1 is a circuit diagram of a main control chip of a main control circuit of a portable fan driving circuit provided in an embodiment of the present application.

[0017] FIG3-2 is a schematic structural diagram of a three-phase drive circuit and a current detection circuit of a portable fan drive circuit provided in an embodiment of the present application.

[0018] FIG3-3 is a schematic structural diagram of a reverse electromotive force detection circuit of a portable fan driving circuit provided in an embodiment of the present application.

[0019] 3-4 are schematic structural diagrams of the interface circuit and charging management circuit of the portable fan driving circuit provided in an embodiment of the present application.

[0020] 3-5 are schematic structural diagrams of an auxiliary chip of a main control circuit of a portable fan driving circuit provided in an embodiment of the present application.

[0021] 3-6 are schematic diagrams of the circuit structure of the indicator light branch and buttons of the portable fan driving circuit provided in an embodiment of the present application.

[0022] 3-7 are schematic structural diagrams of a first speed control component of a portable fan driving circuit provided in an embodiment of the present application.

[0023] 3-8 are schematic structural diagrams of a second speed control device of a portable fan driving circuit provided in an embodiment of the present application.

[0024] 3-9 is a schematic structural diagram of the main control circuit of the portable fan driving circuit provided in an embodiment of the present application.

[0025] 3-10 are schematic structural diagrams of a three-phase drive circuit and a current detection circuit of a portable fan drive circuit provided in an embodiment of the present application.

[0026] 3-11 is a schematic structural diagram of a reverse electromotive force detection circuit of a portable fan driving circuit provided in an embodiment of the present application.

[0027] 3-12 is a schematic diagram of a transistor temperature detection circuit of a portable fan driving circuit provided in an embodiment of the present application.

[0028] 3-13 is a schematic diagram of a battery voltage detection circuit of a portable fan driving circuit provided in an embodiment of the present application.

[0029] 3-14 is a schematic diagram of the burning interface of the portable fan driving circuit provided in an embodiment of the present application.

[0030] FIG3-15 is a schematic structural diagram of a main control chip of a main control circuit of a portable fan driving circuit provided in an embodiment of the present application.

[0031] 3-16 is a schematic structural diagram of a three-phase drive circuit and a battery voltage and current detection circuit of a portable fan drive circuit provided in an embodiment of the present application.

[0032] FIG3-17 is a schematic structural diagram of three three-phase control chips of the main control circuit of the portable fan drive circuit provided in an embodiment of the present application.

[0033] FIG3-18 is a schematic diagram of the structure of the signal amplifying circuit of the portable fan driving circuit provided in an embodiment of the present application.

[0034] FIG3-19 is a schematic structural diagram of a transistor temperature detection circuit of a portable fan driving circuit provided in an embodiment of the present application.

[0035] FIG3-20 is a schematic diagram of the structure of the lighting control circuit of the portable fan driving circuit provided in an embodiment of the present application.

[0036] FIG3-21 is a schematic structural diagram of a Hall detection circuit of a portable fan driving circuit provided in an embodiment of the present application.

[0037] FIG3-22 is a schematic structural diagram of a switch control circuit of a portable fan driving circuit provided in an embodiment of the present application.

[0038] FIG3-23 is a schematic structural diagram of a DC conversion circuit of a portable fan driving circuit provided in an embodiment of the present application.

[0039] Figure 3-24 is a schematic diagram of the block structure of the portable fan provided in an embodiment of the present application.

[0040] FIG4-1 is a schematic structural diagram of a handheld fan provided in an embodiment of the present application.

[0041] FIG4-2 is a schematic structural diagram of a mounting frame in a handheld fan provided in an embodiment of the present application.

[0042] FIG4-3 is a schematic structural diagram of a handheld portion of a handheld fan provided in an embodiment of the present application.

[0043] Figure 4-4 is a structural schematic diagram of a wiring opening in a handheld fan provided in an embodiment of the present application.

[0044] FIG4-5 is a structural schematic diagram 1 of a wire duct in a handheld fan provided in an embodiment of the present application.

[0045] 4-6 is a second structural schematic diagram of a wire duct in a handheld fan provided in an embodiment of the present application.

[0046] 4-7 are schematic structural diagrams of a mid-range position knob assembly and a protection switch button assembly of a handheld fan provided in an embodiment of the present application.

[0047] 4-8 are schematic structural diagrams of an inner shell and an outer shell of a handheld fan provided in an embodiment of the present application.

[0048] 4-9 are schematic structural diagrams of an air inlet and an air outlet in a handheld fan provided in an embodiment of the present application.

[0049] Figure 4-10 is a schematic diagram of the locally enlarged structure of point A in Figure 4-9.

[0050] Figure 4-11 is a schematic structural diagram of a fan assembly in a handheld fan provided in an embodiment of the present application.

[0051] FIG5-1 is a three-dimensional diagram of a portable fan provided in an embodiment of the present application.

[0052] Figure 5-2 is a cross-sectional view of the portable fan provided in an embodiment of the present application.

[0053] Figure 5-3 is an enlarged view of part A in Figure 1-2.

[0054] FIG5-4 is a cross-sectional view of the portable fan provided in an embodiment of the present application from another direction.

[0055] Figure 5-5 is a cross-sectional view of the portable fan provided in an embodiment of the present application.

[0056] 5-6 are cross-sectional views of the portable fan provided in an embodiment of the present application. DETAILED DESCRIPTION

[0057] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. It will be understood that the specific embodiments described herein are only used to explain the present application, rather than to limit the present application. It should also be noted that, for ease of description, only some, rather than all, structures related to the present application are shown in the drawings. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0058] The terms "first," "second," and the like in this application are used to distinguish between different objects, not to describe a particular order. Furthermore, the terms "including," "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or elements is not limited to the listed steps or elements, but may optionally include steps or elements not listed, or may optionally include other steps or elements inherent to the process, method, product, or apparatus.

[0059] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0060] Solution 1, see Figures 1-1 to 1-7.

[0061] Referring to Figures 1-1 to 1-7, in order to solve the above problems, according to one aspect of the present application, an embodiment of the present application provides a portable fan, which includes: an air duct portion 10, the air duct portion 10 includes a main body, an air guide cavity 13 is provided inside the main body, an air outlet 121 and an air inlet 111 are provided at opposite ends of the air duct portion 10, the air outlet 121 and the air inlet 111 are both connected to the air guide cavity 13, and a positioning boss 122 is provided in the main body; a blowing portion 20, the blowing portion 20 includes a rotating fan blade 21 and a driving connection with the rotating fan blade 21 The driving part 22, the rotating fan blade 21 is rotatably installed in the air guide cavity 13 and is arranged toward the air outlet 121; the driving part 22 includes a stator 221 and a rotor 222 sleeved on the outside of the stator 221, the rotor 222 is fixedly installed on the rotating fan blade 21 and is coaxially arranged with the rotating fan blade 21, and the stator 221 is fixedly sleeved on the positioning boss 122; the hand-held part 30, the hand-held part 30 is connected to the air duct part 10, and an installation cavity 34 is provided in the hand-held part 30, and a power supply component 31 is installed in the installation cavity 34, and the power supply component 31 is electrically connected to the driving part 22. The portable fan provided in this embodiment has a driving part 22 connected to the rotating fan blade 21, which is set as a stator 221 and a rotor 222 mounted outside the stator 221, and the rotor 222 is fixedly mounted on the rotating fan blade 21 and coaxially arranged with the rotating fan blade 21. At the same time, the stator 221 is fixedly mounted on the positioning boss 122, so that the power generated by the driving part 22 provided in this embodiment can be directly transmitted to the rotating fan blade 21 through the rotor 222, without the need to set a transmission device between the driving part 22 and the rotating fan blade 21, thereby effectively improving the transmission efficiency of the portable fan provided in this embodiment.

[0062] In a preferred embodiment, the power supply component 31 provided in this embodiment is a battery.

[0063] Referring to Figures 1 and 5, in a specific embodiment, the main body in this embodiment includes a first shell 11 and a second shell 12, the first shell 11 is connected to the second shell 12, and an air guide cavity 13 is formed between the first shell 11 and the second shell 12, the first shell 11 is provided with an air inlet 111, the second shell 12 is provided with an air outlet 121, and the second shell 12 is provided with a positioning boss 122, which extends along the extension direction of the air guide cavity 13.

[0064] Referring to Figures 4 to 7, in a specific embodiment, a fixing hole is provided on the rotating fan blade 21 in this embodiment, and the axis of the fixing hole is collinear with the axis of the rotating fan blade 21. The blowing part 20 also includes a rotating shaft 23, and the first end of the rotating shaft 23 is fixedly inserted into the fixing hole; a positioning hole 1221 is provided inside the positioning boss 122, and the axis of the positioning hole 1221 is collinear with the axis of the rotating shaft 23, and the second end of the rotating shaft 23 is rotatably inserted into the positioning hole 1221.

[0065] 4 to 7 , to extend the service life of the portable fan provided in this embodiment, the blowing unit 20 in this embodiment further includes a bearing unit 24. The outer ring of the bearing unit 24 is fixed within the positioning hole 1221, and the inner ring of the bearing unit 24 is sleeved around the second end of the rotating shaft 23. By disposing the bearing unit 24 provided in this embodiment between the positioning hole 1221 and the rotating shaft 23, with the outer ring of the bearing unit 24 provided in this embodiment fixed within the positioning hole 1221 and the inner ring sleeved around the second end of the rotating shaft 23, direct friction between the positioning hole 1221 and the rotating shaft 23 is avoided, thereby effectively extending the service life of the portable fan provided in this embodiment.

[0066] 4 and 5 , in a specific embodiment, the bearing portion 24 includes a rolling bearing, and the blowing portion 20 further includes a stopper 25. The stopper 25 is mounted on the second end of the rotating shaft 23, and the bearing portion 24 is located between the stopper 25 and the first end of the rotating shaft 23. Providing the stopper 25 on the second end of the rotating shaft 23 effectively limits the radial movement of the rolling bearing.

[0067] As shown in Figures 4 and 5, in a specific embodiment, to facilitate installation of the rolling bearing provided by this embodiment, multiple bearing portions 24 are provided in this embodiment, and an inner flange 12211 is provided on the inner sidewall of the positioning hole 1221. The inner flange 12211 is disposed between two adjacent bearing portions 24 to space the two adjacent bearing portions 24 apart. The limiting member 25 provided on the second end of the rotating shaft 23 provided by this embodiment can effectively limit the inner ring of the rolling bearing provided by this embodiment, and the inner flange 12211 provided on the inner sidewall of the positioning hole 1221 can effectively limit the outer ring of the bearing, thereby effectively installing the rolling bearing provided by this embodiment.

[0068] In a preferred embodiment, the bearing portion 24 provided in this embodiment is a ball bearing, and lubricating oil is provided in the ball bearing provided in this embodiment.

[0069] In a preferred embodiment, the bearing portion 24 provided in this embodiment is a ceramic bearing, and lubricating oil is provided in the ceramic bearing provided in this embodiment.

[0070] In a preferred embodiment, the bearing portion 24 provided in this embodiment is a magnetic bearing.

[0071] In a preferred embodiment, the blowing part 20 provided in this embodiment also includes an elastic part. The elastic part provided in this embodiment is sleeved on the rotating shaft 23. The two ends of the elastic part provided in this embodiment are respectively abutted against the inner ring of the rolling bearing and the rotating fan blade 21. The elastic part provided in this embodiment can apply an elastic force to the inner ring of the rolling bearing away from the air inlet 111. Through the elastic part provided in this embodiment, the rolling bearing can be pre-tightened, thereby effectively improving the service life of the rolling bearing.

[0072] Referring to Figures 6 and 7 , in an optional embodiment, to extend the service life of the portable fan provided by this embodiment, the bearing portion 24 in this embodiment includes a sliding bearing, and the blowing portion 20 further includes two sealing rings 26. Both sealing rings 26 are sleeved on the rotating shaft 23 and are located on either side of the sliding bearing. By disposing the sliding bearing provided by this embodiment between the rotating shaft 23 and the positioning hole 1221, and by fixing the inner ring of the sliding bearing to the second end of the rotating shaft 23 and the outer ring to the fixing hole, the friction between the rotating shaft 23 and the positioning hole 1221 is converted into friction between the inner and outer rings of the sliding bearing, thereby avoiding friction between the rotating shaft 23 and the positioning hole 1221, thereby effectively extending the service life of the portable fan provided by this embodiment.

[0073] 4 to 7 , in a specific embodiment, the handheld portion 30 includes a third shell 32 and a fourth shell 33 . The third shell 32 is connected to the fourth shell 33 , and a mounting cavity 34 is formed between the third shell 32 and the fourth shell 33 .

[0074] Referring to Figures 4 to 7, in a specific embodiment, the first shell 11 in this embodiment includes a main body 112 and a duct lining 113, the duct lining 113 is installed on the main body 112, an air duct 1131 is provided inside the duct lining 113, and an air guide cavity 13 is formed between the duct lining 113 and the second shell 12.

[0075] Due to their low price, single-phase motors are currently the most commonly used power source for small portable handheld fans on the market. However, due to their low speed, single-phase motors cannot provide strong wind power, resulting in a poor user experience. To achieve stronger wind power, a high-speed motor is required. However, high-speed motors take up a lot of space and are prone to wear and tear on portable fans.

[0076] In order to solve the above problems, the driving unit 22 in this embodiment is a three-phase motor. By setting the driving unit 22 as a three-phase motor, the rotation speed of the rotating blades 21 can be effectively increased, so that the portable fan provided by this embodiment can provide stronger wind force, effectively improving the user experience. At the same time, due to the high rotation speed of the three-phase motor, in order to avoid rapid wear between the rotating shaft and the positioning hole due to high-speed rotation and to ensure the service life of the portable fan provided by this embodiment, the portable fan provided by this embodiment is provided with a bearing portion between the positioning hole provided in this embodiment and the rotating shaft. By providing the bearing portion, the friction between the positioning hole and the rotating shaft can be converted from sliding friction to rolling friction inside the bearing portion, thereby avoiding wear between the positioning hole and the rotating shaft, and effectively improving the service life of the portable fan provided by this embodiment.

[0077] Referring to Figures 1 to 7, in a specific embodiment, a charging port 35 is provided on the handheld part 30 provided in this embodiment, and the charging port 35 is electrically connected to the power supply component 31; by providing the charging port 35 on the handheld part 30 provided in this embodiment, and electrically connecting the charging port 35 to the power supply component 31, the power supply component 31 provided in this embodiment can be electrically connected to an external power source through the charging port 35, thereby ensuring the battery life of the portable fan provided in this embodiment.

[0078] In a preferred embodiment, a discharge port is provided on the handheld portion provided in this embodiment, and the discharge port provided in this embodiment is electrically connected to the power supply component. The discharge port provided in this embodiment can be electrically connected to an external electronic device, and the power supply component can be transmitted to the external electronic device through the discharge port provided in this embodiment.

[0079] In a preferred embodiment, a grille assembly is provided on the air inlet provided in this embodiment, and the grille assembly provided in this embodiment includes a first grille member and a second grille member. The first grille member provided in this embodiment is fixedly connected to the first shell, and the second grille member provided in this embodiment is pivotally connected to the first grille member. The first grille member provided in this embodiment is provided with multiple first openings, and the second grille member provided in this embodiment is provided with multiple second openings. The multiple first openings provided in this embodiment can correspond one-to-one with the multiple second openings. The second grille member provided in this embodiment has a shielding state that completely shields the first opening and an open state in which the first opening overlaps with the second opening. By rotating the second grille member, the second grille member can be switched between the shielding state and the open state. The grille assembly provided in this embodiment can effectively adjust the air intake of the air inlet, thereby effectively improving the user experience.

[0080] In a preferred embodiment, the air duct portion 10 and the hand-held portion 30 provided in this embodiment are fixedly connected; of course, in other embodiments, the air duct portion 10 and the hand-held portion 30 provided in this embodiment may also be pivotally connected so as to be relatively rotatable.

[0081] In a specific embodiment, the third shell 32 provided in this embodiment is integrally formed by injection molding with the first shell 11 , and the fourth shell 33 is integrally formed by injection molding with the second shell 12 .

[0082] In another embodiment, the third shell 32 provided in this embodiment is pivotally connected to the first shell 11, the fourth shell 33 is pivotally connected to the second shell 12, and the pivot axis of the third shell 32 and the first shell 11 is coaxial with the pivot axis of the fourth shell 33 and the second shell 12.

[0083] In summary, the portable fan provided by the present embodiment has at least the following beneficial technical effects: the portable fan provided by the present embodiment is configured such that the driving portion 22 connected to the rotating fan blade 21 is configured as a stator 221 and a rotor 222 sleeved outside the stator 221, and the rotor 222 is fixedly mounted on the rotating fan blade 21 and coaxially arranged with the rotating fan blade 21, and the stator 221 is fixedly sleeved on the positioning boss 122, so that the power generated by the driving portion 22 provided by the present embodiment can be directly transmitted to the rotating fan blade 21 through the rotor 222, without the need to set a transmission device between the driving portion 22 and the rotating fan blade 21, thereby effectively improving the transmission efficiency of the portable fan provided by the present embodiment.

[0084] Option 2, see Figures 2-1 to 2-3.

[0085] As shown in FIG. 2-1 to FIG. 2-3 , the control circuit of the portable fan includes a charging and supply circuit 20 , a fan driving circuit 30 , a control switch Q2 and a main control circuit 50 .

[0086] The charging and power supply circuit 20 is configured to electrically connect an external power source and the battery 14 to receive an external voltage VCC to charge the battery 14 and output a power supply voltage V0. The fan drive circuit 30 is electrically connected to the charging and power supply circuit 20 and the fan assembly 12 to drive the fan assembly 12 to rotate. The control terminal of the control switch Q2 is configured to receive the external voltage VCC and to be grounded. The first conductive terminal of the control switch Q2 is configured to electrically connect to the battery 14 to receive the output voltage of the battery 14. The second conductive terminal of the control switch Q2 is configured to electrically connect to the fan drive circuit 30. The control switch Q2 is closed when receiving the external voltage VCC and is closed when not receiving the external voltage VCC.

[0087] The main control circuit 50 is electrically connected to the charging and supply circuit 20 , the fan driving circuit 30 , and the control switch Q2 .

[0088] In this embodiment, as shown in FIG2-1 , the charging and power supply circuit 20 includes a charging port 21 and a charging management chip 22. A power supply terminal 211 of the charging port 21 receives the external voltage VCC and is electrically connected to a charging input pin VIN of the charging management chip 22. The power supply terminal 211 of the charging port 21 is also electrically connected to the negative terminal of a voltage regulator D1, the positive terminal of which is grounded. A switch pin SW of the charging management chip 22 is electrically connected to the positive terminal BAT+ of the battery 14 via a first inductor L1. A boost output pin VOUT of the charging management chip 22 is configured to output the supply voltage V0. The boost input pin of the charging management chip 22 is connected to the node between the battery 14 and the first inductor L1 via a first connection resistor 201 and to ground via a first grounding capacitor 202. The charging management chip 22, the voltage regulator D1, and the first inductor L1 effectively manage the charging and discharging of the charging port and the battery, and can output the supply voltage required by other circuits. This configuration is simple, easy to implement, and highly secure.

[0089] The key input terminal KEY of the charging management chip 22 is electrically connected to the main control circuit 50; the first LED driving pin LED1 of the charging management chip 22 is grounded via the first grounding resistor 203 and the second grounding resistor 204 in sequence, and the second LED driving pin LED2 of the charging management chip 22 is connected to the positive terminal of the battery 14 via the second connection resistor 205; the first indicator pin LED1 of the main control circuit 50 is grounded via the first indicator branch 51, and the second LED driving pin LED2 of the charging management chip 22 is also grounded via the second indicator branch 23. The first indicator branch 51 and the second indicator branch 23 both include a current limiting resistor R and an indicator LED connected in series. It can be understood that the key input terminal SW of the charging management chip 22 is electrically connected to the main control circuit 50, allowing the main control circuit 50 to control the charging management chip 22 and ensure the reliability of the control circuit; the charging and power supply status of the charging and power supply circuit 20 can be indicated via the first indicator branch 51 and the second indicator branch 23, improving the user experience. The main control circuit 50 can be an MCU.

[0090] As shown in FIG2-2 , the control end of the control switch Q2 is configured to receive the external voltage VCC and is grounded. The first conductive end of the control switch Q2 is configured to be electrically connected to the battery 14 to receive the output voltage of the battery 14. The second conductive end of the control switch Q2 is configured to be electrically connected to the fan drive circuit 30. The control switch Q2 is closed when receiving the external voltage VCC and is closed when not receiving the external voltage VCC. In this case, the fan drive circuit 30 is powered by the battery 14. Through the control switch Q2, when the external voltage VCC is connected, the external voltage VCC can directly power the fan drive circuit 30, preventing the fan drive circuit 30 from using the output voltage of the battery 14. This not only allows the battery 14 to charge faster, but also prevents the battery 14 from being charged and discharged simultaneously, which could affect its service life.

[0091] As shown in Figure 2-2, the control terminal of the control switch Q2 can be grounded via a third grounding resistor 206 and electrically connected to the second conductive terminal of the control switch Q2 and the fan drive circuit 30 via a first diode D2. The second control switch is a PMOS (P-Metal-Oxide-Semiconductor) field-effect transistor. It will be appreciated that the third grounding resistor 206 and the first diode D2 can improve the stability and safety of the control circuit. The control switch Q2 is a PMOS field-effect transistor, which also has the technical advantages of low cost, simple structure and control.

[0092] As shown in FIG2-2, the fan drive circuit 30 includes a second inductor L2, a third control switch Q3, a second diode D3 and a boost feedback branch 31. One end of the second inductor L2 is used to electrically connect to the charging and power supply circuit 20 to receive the external voltage VCC or the output voltage MVCC of the battery 14. The other end of the second inductor L2 is connected to the fan assembly 12 via the second diode D3. The first conductive end of the third control switch Q3 is connected to the node between the second inductor L2 and the second diode D3. The second conductive end of the third control switch Q3 is grounded. The control end of the third control switch Q3 is electrically connected to the second of the main control circuit 50. The pulse width signal output terminal FPWM receives the second pulse width control signal output by the main control circuit 50. One end of the boost feedback branch 31 is connected to the node between the second diode D3 and the fan assembly 12, and the other end of the boost feedback branch 31 is grounded. The boost feedback branch 31 includes a first voltage-dividing resistor 311 and a second voltage-dividing resistor 312 connected in series. The node between the first voltage-dividing resistor 311 and the second voltage-dividing resistor 312 is connected to the boost feedback terminal FAAD of the main control circuit 50 via a third voltage-dividing resistor 313. The node between the third voltage-dividing resistor 313 and the main control circuit 50 is also connected to ground via a second grounding capacitor 314. It can be understood that, with the above-described structure, the fan drive circuit 30 can charge and discharge the second inductor L2 by controlling the switching of the third control switch Q3, thereby increasing the voltage on the right side of the second inductor L2 and supplying power to the fan assembly 12. The boost feedback branch 31 also samples the boosted voltage and feeds it back to the main control circuit 50, allowing the main control circuit 50 to adjust the second pulse width control signal provided to the third control switch Q3, thereby maintaining a substantially constant voltage across the fan assembly 12. Furthermore, by adjusting the second pulse width control signal provided to the third control switch Q3, the voltage provided to the fan assembly 12 can be increased or decreased, thereby controlling the fan assembly 12 to achieve different speeds.

[0093] Furthermore, the fan drive circuit 30 may further include a fourth control switch Q4, a third diode D4, a first feedback resistor 315, and a second feedback resistor 316. The cathode of the third diode D4 is connected to the anode of the fan assembly 12, the cathode of the fan assembly 12 is connected to the anode of the third diode D4 and the first conducting end of the fourth control switch Q4, the control end of the fourth control switch Q4 is electrically connected to the fan enable end FAEN of the main control circuit 50, the second conducting end of the fourth control switch Q4 is grounded via the first feedback resistor 315, the node between the second conducting end of the fourth control switch Q4 and the first feedback resistor 315 is also electrically connected to the load feedback end LOAD AD of the main control circuit 50 via the second feedback resistor 316, and the node between the second feedback resistor 316 and the main control circuit 50 is also grounded via a third grounding capacitor 317. Through the fourth control switch Q4, the voltage boosted by the second inductor L2 and the third control switch Q3 can be connected to the ground via the fan assembly 12 to form a loop, thereby driving the fan assembly 12 to rotate. The signal at the node between the second conduction end of the fourth control switch Q4 and the first feedback resistor 315 is sampled through the first feedback resistor 315 and fed back to the main control circuit 50, so that the main control circuit 50 can detect whether the fan assembly 12 is blocked or short-circuited.

[0094] Option 3, see Figures 3-1 to 3-24.

[0095] Please refer to Figures 3-1 to 3-3. The first embodiment of the present application provides a driving circuit for a portable fan. The driving circuit of the portable fan can be used for various types of fans. Specifically, the driving circuit of the portable fan includes: a main control circuit 11, a three-phase driving circuit 12 and a reverse electromotive force detection circuit 14.

[0096] The three-phase drive circuit 12 includes at least three signal input terminals 121 and three drive signal output terminals 122. The at least three signal input terminals 121 are electrically connected to the main control circuit 11 to receive control signals respectively. The three drive signal output terminals 122 are used to electrically connect to the three signal terminals (U, V, W) of the DC brushless fan motor to output three-phase drive signals to drive the DC brushless fan motor to rotate. The reverse electromotive force detection circuit 14 includes three detection branches 141. Each detection branch 141 includes a detection terminal 1411 and a detection terminal electrically connected to the detection terminal. The three detection output ends 1411 of the three detection branches 141 are respectively electrically connected to the three drive signal output ends 122, and the three detection output ends 1412 of the three detection branches 141 are respectively electrically connected to the main control circuit 11, so as to output the first detection signal, the second detection signal and the third detection signal to the main control circuit respectively, so that the main control circuit 11 obtains the phase of the three-phase drive signal according to the first detection signal, the second detection signal and the third detection signal to adjust the control signal.

[0097] Please refer to Figure 3-3. The detection branch 141 includes a first detection resistor R1, a second detection resistor R2 and a third detection resistor R3. The first detection resistor R1 and the second detection resistor R2 are connected in series, and the end of the first detection resistor R1 away from the second detection resistor R2 is the detection end 1411. The end of the second detection resistor R2 away from the first detection resistor R1 is grounded. The node between the first detection resistor R1 and the second detection resistor R2 is the detection output end 1412.

[0098] The three-phase drive circuit 12 can improve the energy-saving performance and control performance of the fan motor, and extend the service life of the drive circuit and the fan of the portable fan. The reverse electromotive force detection circuit 14 can also make the main control circuit 11 easily know the phase of the DC brushless fan motor, so as to send a corresponding control signal to the three-phase drive circuit 12, effectively control the drive of the DC brushless fan motor, and improve the reliability and stability of the drive.

[0099] Please refer to FIG3-2 , the three-phase drive circuit 12 includes first to ninth transistors Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8, and Q9. The first conducting ends 1211 of the first to third transistors Q1, Q2, and Q3 are all connected to the power supply end 1212. The first conducting end 1211 of the fourth transistor Q4 is connected to the power supply end 1212. The first conducting end 1211 of the fifth transistor Q5 is connected to the power supply end 1212. The first conducting end 1211 of the sixth transistor Q6 is connected to the power supply end 1212. 1 is connected to the power supply terminal 1212, the control terminals of the fourth to sixth transistors Q4, Q5, and Q6 are respectively electrically connected to the main control circuit 11, and the control terminals of the seventh to ninth transistors Q7, Q8, and Q9 are respectively electrically connected to the control terminals of the fourth to sixth transistors Q4, Q5, and Q6 for receiving the control signal, the second conduction terminals 1213 of the fourth to sixth transistors Q4, Q5, and Q6 are all grounded, and the first conduction terminal 1211 of the seventh transistor Q7 is connected to the first conduction terminal 1212 of the first transistor Q1. The second conduction terminal 1213 of the seventh transistor Q7 is connected to the ground. The first conduction terminal 1211 of the eighth transistor Q8 is connected to the second conduction terminal 1213 of the second transistor Q2. The second conduction terminal 1213 of the eighth transistor Q8 is grounded. The first conduction terminal 1211 of the ninth transistor Q9 is connected to the second conduction terminal 1213 of the third transistor Q3. The second conduction terminal 1213 of the ninth transistor Q9 is grounded. A node between the first conduction terminal 1211 of the seventh transistor Q7 and the second conduction terminal 1213 of the first transistor Q1, a node between the first conduction terminal 1211 of the eighth transistor Q8 and the second conduction terminal 1213 of the second transistor Q2, and a node between the first conduction terminal 1211 of the ninth transistor Q9 and the second conduction terminal 1213 of the third transistor Q3 respectively serve as the three drive signal output terminals 122. The at least three signal input terminals 121 are three PWM signal input terminals, and the control signal includes three PWM signals.

[0100] As shown in FIG3-2 , the portable fan drive circuit further includes a current detection circuit 15. The second conducting ends 1213 of the seventh to ninth transistors Q7, Q8, and Q9 are all grounded via the current detection circuit 15. The current detection circuit 15 is also electrically connected to the main control circuit 11. The current detection circuit 15 includes a sensing resistor 151 and a sensing capacitor 152. The second conducting ends 1213 of the seventh to ninth transistors Q7, Q8, and Q9 are grounded via the sensing resistor 151 and the sensing capacitor 152, respectively. The node between the sensing resistor 151 and the sensing capacitor 152 is electrically connected to the main control circuit 11. Through the current detection circuit 15, when a current anomaly occurs, the main control circuit 11 can control the portable fan drive circuit to stop operating or operate at a lower power, thereby providing overcurrent protection for the portable fan drive circuit and improving the reliability and service life of the portable fan drive circuit.

[0101] Please refer to Figures 3-4 and 3-6. The driving circuit of the portable fan also includes an interface circuit 16 and a charging management circuit 17. The interface circuit 16 is used to electrically connect to an external power supply to receive an external voltage. The charging management circuit 17 is electrically connected between the interface circuit 16 and the battery VBAT, and is used to receive the external voltage and charge the battery VBAT or output a supply voltage; the driving circuit of the portable fan also includes a button 31, one end of the button 31 is connected to the main control circuit 11, and the other end is grounded; the driving circuit of the portable fan also includes an indicator light branch 19, and the indicator light branch 19 includes a light-emitting diode and a resistor connected in series, the positive pole of the light-emitting diode is used to electrically connect to the main control circuit 11, and the negative pole of the light-emitting diode is grounded.

[0102] Specifically, in this embodiment, the portable fan drive circuit can be used in neck-hanging fans and handheld fans, but is not limited to neck-hanging fans and handheld fans. It can also be applied to other portable fans such as table fans, floor fans, clip fans, and folding fans. The two brushless DC fan motors are respectively provided on the left and right sides of the neck-hanging fan and are used to drive the left and right fan blades of the neck-hanging fan to rotate.

[0103] As shown in Figures 3-1, 3-2 and 3-5, the main control circuit 11 may include a main control chip 111 and an auxiliary chip 113. The main control circuit 11 includes the main control chip 111 and the auxiliary chip 113. The number of the three-phase drive circuit 12, the reverse electromotive force detection circuit 14 and the DC brushless fan motor are all two and one-to-one corresponding. The main control chip 111 is electrically connected to one of the three-phase drive circuits 12 to output the control signal to one of the three-phase drive circuits 12 to drive the corresponding one of the DC brushless fan motors. The reverse electromotive force detection circuit 14 is electrically connected to the corresponding three-phase drive circuit 12 and outputs the corresponding first detection signal, the second detection signal and the third detection signal to the main control chip 111, so that the main control chip 111 can know the three-phase of the three-phase drive circuit 12. The phase of the driving signal is used to adjust the control signal output to one of the three-phase driving circuits 12; the auxiliary chip 113 is electrically connected to another three-phase driving circuit 12 to output the control signal to the other three-phase driving circuit 12 to drive the corresponding other DC brushless fan motor, and the other reverse electromotive force detection circuit 14 is electrically connected to the corresponding three-phase driving circuit 12 and outputs the corresponding first detection signal, the second detection signal and the third detection signal to the auxiliary chip 113, so that the auxiliary chip 113 knows the phase of the three-phase driving signal of the other three-phase driving circuit 12 to adjust the control signal output to the other three-phase driving circuit 12.

[0104] In this embodiment, the main control chip 111, the corresponding three-phase drive circuit 12, and the corresponding reverse electromotive force detection circuit 14 are arranged on a module (such as a first circuit board), and can be arranged on the same side of the neck-hanging fan as the corresponding DC brushless fan motor. The auxiliary chip 113, the corresponding three-phase drive circuit 12, and the corresponding reverse electromotive force detection circuit 14 are arranged on another module (such as a second circuit board independent of the first circuit board), and can be arranged on the other side of the neck-hanging fan with the corresponding DC brushless fan motor. It can be understood that the above design has good rationality and compactness, and can also improve the reliability of connection and drive. However, the layout of the three-phase drive circuit 12, the reverse electromotive force detection circuit 14, the main control chip 111, and the auxiliary chip 113 can be varied. For example, the three-phase drive circuit 12, the reverse electromotive force detection circuit 14, the main control chip 111, and the auxiliary chip 113 are all arranged on the same circuit board, or the three-phase drive circuit 12 and the reverse electromotive force detection circuit 14 are arranged on one circuit board, and the main control chip 111 and the auxiliary chip 113 are arranged on another circuit board. The specific selection can be made according to actual needs and will not be repeated here.

[0105] Referring to Figures 3-7 and 3-8 , the portable fan drive circuit further includes a first connector 261 and a speed control interface circuit 26 having a second connector 262. The first and second pins of the first connector 261 are electrically connected to the main control chip 111, respectively. The third pin of the first connector 261 is grounded. The first pin of the second connector 262 is connected to the battery VBAT via a first connection resistor and to the auxiliary chip 113 via a second connection resistor. The second pin of the second connector 262 is connected to the auxiliary chip 113 via a third connection resistor. The third pin of the second connector 262 is grounded. Furthermore, the pins of the first connector 261 and the second connector 262 can be electrically connected one-to-one, allowing for synchronous speed adjustment of the two brushless DC fan motors.

[0106] Referring to Figures 3-9 to 3-14, a second embodiment of the present application provides a driving circuit for a portable fan. The portions of the driving circuit that are identical to those of the first embodiment are not described in detail. The following focuses on the differences between this embodiment and the first embodiment. First, the main control circuit 11 of this embodiment differs from the main control circuit 11 of the first embodiment and may primarily include a main control chip 111.

[0107] As shown in FIG3-10, in this embodiment, the three-phase drive circuit 12 includes first to sixth transistors Q1, Q2, Q3, Q4, Q5, and Q6. The first conduction terminals 1211 of the first to third transistors Q1, Q2, and Q3 are all connected to the power supply terminal 1212. The first conduction terminal 1211 of the fourth transistor Q4 is connected to the second conduction terminal 1213 of the first transistor Q1. The first conduction terminal 1211 of the fifth transistor Q5 is connected to the second conduction terminal 1213 of the second transistor Q2. The first conduction terminal 1211 of the sixth transistor Q6 is connected to the second conduction terminal 1213 of the third transistor Q3. A node between the first conduction end 1211 of the transistor Q4 and the second conduction end 1213 of the first transistor Q1, a node between the first conduction end 1211 of the fifth transistor Q5 and the second conduction end 1213 of the second transistor Q2, and a node between the first conduction end 1211 of the sixth transistor Q6 and the second conduction end 1213 of the third transistor Q3 respectively serve as the three drive signal output ends 122. The control ends of the first to sixth transistors Q1, Q2, Q3, Q4, Q5, and Q6 are respectively used to be electrically connected to the main control circuit 11 to receive the control signals; the control signals include six PWM signals.

[0108] As shown in FIG3-10 , similar to the first embodiment, the second conduction end 1213 of the sixth transistor Q6 is grounded via the current detection circuit 15, and the current detection circuit 15 is also electrically connected to the main control circuit 11; the current detection circuit 15 includes a sensing resistor 151 and a sensing capacitor 152, the second conduction end 1213 of the sixth transistor Q6 is grounded via the sensing resistor 151, the sensing capacitor 152 is connected in parallel with the sensing resistor 151, and a node between the sensing resistor 151 and the second conduction end 1213 of the sixth transistor Q6 is electrically connected to the main control circuit 11; the current detection circuit 15 also includes a first series resistor 153, a second series resistor 154, and a parallel resistor 155, the parallel resistor 155 being connected in parallel with the sensing resistor 151, the first series resistor 153 being connected between one end of the sensing capacitor 152 and one end of the sensing resistor 151, and the second series resistor 154 being connected between the other end of the sensing capacitor 152 and the other end of the sensing resistor 151. Through the current detection circuit 15, when a current abnormality occurs, the main control circuit 11 can control the driving circuit of the portable fan to stop working or operate at a lower power, so as to protect the driving circuit of the portable fan from overcurrent and improve the reliability and service life of the driving circuit of the portable fan.

[0109] As shown in FIG. 3-11 , the reverse electromotive force detection circuit 14 of the second embodiment is substantially the same as the reverse electromotive force detection circuit 14 of the first embodiment, and will not be described in detail here.

[0110] As shown in Figure 3-12, the driving circuit of the portable fan also includes a transistor temperature detection circuit 24, which can be arranged adjacent to each transistor of the three-phase driving circuit 12, and includes a first voltage-dividing resistor 241 and a thermistor 242 connected in series. The thermistor 242 is used to sense the temperature of each transistor of the three-phase driving circuit 12. The node between the first voltage-dividing resistor 241 and the thermistor 242 is electrically connected to the main control circuit 11 and is used to output a temperature signal, so that the main control circuit 11 controls whether the driving circuit of the portable fan enters a temperature protection state according to the temperature signal; the thermistor 242 is connected between the first voltage-dividing resistor 241 and the ground, and the transistor temperature detection circuit 24 also includes a voltage-stabilizing capacitor 243 connected in parallel with the thermistor 242. Through the transistor temperature detection circuit 24, the main control circuit 11 can know whether the temperature of each transistor of the three-phase drive circuit 12 is abnormal, and when an abnormality occurs, it can control the drive circuit of the portable fan to stop working or operate at a lower power, so as to protect the drive circuit of the portable fan from overtemperature and improve the reliability and service life of the drive circuit of the portable fan.

[0111] As shown in FIG3-13 , the portable fan's drive circuit further includes a battery voltage detection circuit 25 electrically connected between the positive terminal of the battery VBAT and ground. The output of the battery voltage detection circuit 25 is electrically connected to the main control circuit 11. Through the battery voltage detection circuit 25, the main control circuit 11 can determine whether the battery voltage is normal. If the battery voltage is abnormal, the main control circuit 11 can control the portable fan's drive circuit to stop operating or operate at a lower power, thereby improving the reliability and service life of the portable fan's drive circuit.

[0112] Specifically, the battery voltage detection circuit 25 includes a second voltage-dividing resistor 251 and a third voltage-dividing resistor 252 connected in series, and the node between the second voltage-dividing resistor 251 and the third voltage-dividing resistor 252 is electrically connected to the main control circuit 11. It can be understood that the battery voltage detection circuit 25 has a simple structure, high reliability, and low cost.

[0113] As shown in FIG3-14 , the driving circuit of the portable fan of the second embodiment of the present application further has a burning interface 28 for burning the control program into the main control circuit 11 . The burning interface 28 may be a SWD burning interface, but is not limited thereto.

[0114] Please refer to Figures 15 and 16. The third embodiment of the present application provides a driving circuit for a portable fan. The parts of the driving circuit of the portable fan that are the same as those of the driving circuit of the portable fan of the second embodiment are not described in detail. The following mainly focuses on the differences between the driving circuit of the portable fan of the third embodiment and the driving circuit of the portable fan of the second embodiment.

[0115] As shown in Figures 3-15 to 3-17, the three-phase drive circuit 12 of the third embodiment is basically the same as the three-phase drive circuit 12 of the second embodiment, and the main control circuit 11 of the third embodiment is different from the main control circuit 11 of the second embodiment. The main control circuit 11 includes a main control chip 111 and three three-phase control chips 112, and each of the three-phase control chips 112 is electrically connected to the main control chip 111 and the three-phase drive circuit 12.

[0116] As shown in Figures 3-16 and 3-18, the portable fan drive circuit further includes a filter capacitor 253 and a sampling resistor 254 connected in series. The sampling resistor 254 is connected between the filter capacitor 253 and ground, and the node between the filter capacitor 253 and the sampling resistor 254 is electrically connected to the main control circuit 11. Furthermore, the portable fan drive circuit further includes a signal amplification circuit 29, the input end of which is connected to the node between the filter capacitor 253 and the sampling resistor 254. The signal amplification circuit 29 is configured to amplify the signal sampled by the sampling resistor 254 (i.e., the signal at the node between the filter capacitor 253 and the sampling resistor 254) and provide the amplified signal to the main control circuit 11. This allows the main control circuit 11 of the portable fan drive circuit to keenly detect abnormal voltage or current signals when an abnormality occurs in the entire portable fan drive circuit. The main control circuit 11 can then perform abnormal protection operations, such as stopping operation or reducing the fan speed, thereby improving the safety of the portable fan drive circuit.

[0117] As shown in FIG3-19 , the transistor temperature detection circuit 24 of the third embodiment is substantially the same as that of the second embodiment, and will not be described in detail here.

[0118] Please refer to Figure 3-20, which is a schematic diagram of the structure of a light control circuit 30 of the portable fan drive circuit provided in the third embodiment of the present application. The light control circuit 30 includes a light-emitting element 301 and a control switch 302. The positive electrode of the light-emitting element 301 receives a driving voltage, and the negative electrode of the light-emitting element 301 is grounded via a resistor and the two conductive terminals of the control switch 302. The control terminal of the control switch 302 is electrically connected to the main control circuit 11, so that the main control circuit 11 outputs a light control signal to the control terminal of the control switch 302 to control the light emission of the light-emitting element 301.

[0119] As shown in Figure 3-21, the driving circuit of the portable fan also includes a Hall detection circuit 23, which is electrically connected to the main control circuit 11, and is used to detect the magnetic field generated by the DC brushless fan motor and output a Hall detection signal to the main control circuit 11, so that the main control circuit 11 can obtain the position of the rotor of the DC brushless fan motor based on the Hall detection signal, and then can provide a corresponding control signal to control the operation of the three-phase drive circuit 12. At this time, the startup time of the fan using the driving circuit of the portable fan is shorter, there will be no jitter during startup, and the user experience is higher.

[0120] As shown in Figure 3-21, the Hall detection circuit 23 also includes a motor temperature detection element 232, which is connected between the Hall element 231 of the Hall detection circuit 23 and the main control circuit 11. The motor temperature detection element 232 can be a sampling resistor. Through the motor temperature detection element 232, the main control circuit 11 can know whether the temperature of the DC brushless fan motor is abnormal, and when an abnormality occurs, it can control the drive circuit of the portable fan to stop working or operate at a lower power, so as to protect the drive circuit of the portable fan from over-temperature and improve the reliability and service life of the drive circuit of the portable fan.

[0121] As shown in Figures 3-17 and 3-22, the driving circuit of the portable fan also includes a voltage conversion circuit 20, which is used to receive the battery voltage (VB+) and convert the battery voltage into a driving voltage (such as 15V), and provide the driving voltage to the power supply ends of the three three-phase control chips 112. The main control chip 111 is used to output the main control signal to the three three-phase control chips 112, so that the three three-phase control chips 112 respectively output the control signal to the three-phase drive circuit 12.

[0122] The portable fan drive circuit also includes a switch control circuit 21, which is electrically connected to the battery VBAT, the voltage conversion circuit 20, and the main control circuit 11, and is used to control the operation of the voltage conversion circuit 20. The switch control circuit 21 includes a button 211, a first switch 212, a second switch 213, and a third switch 214. The two conductive ends of the first switch 212 are respectively connected to the positive electrode of the battery VBAT and the input terminal of the voltage conversion circuit 20. The control end of the first switch 212 is grounded via the two conductive ends of the third switch 214. The positive electrode of the battery VBAT is also connected to the control end of the third switch 214 via the two conductive ends of the first switch 212 and a one-way diode 215. The control end of the second switch 213 is grounded via the button 211. The control end of the third switch 214 is electrically connected to the main control circuit 11, and the node between the second switch 213 and the one-way diode 215 is also electrically connected to the switch signal terminal of the main control circuit 11.

[0123] When the button 211 is pressed and turned on, the second switch tube 213 is turned on, the third switch tube 214 is turned on, and the node between the second switch tube 213 and the one-way diode 215 outputs a first switching signal (ON) to the switch signal terminal of the main control circuit 11. The first switch tube 212 is turned on, so that the battery voltage of the battery VBAT is provided to the voltage conversion circuit 20. When the button 211 is no longer pressed, the second switch tube 213 is turned off, and the main control circuit 11 outputs a power-on signal to the control terminal of the third switch tube 214 based on the first switching signal to maintain the conduction of the third switch tube 214. The battery voltage of the battery VBAT is provided to the voltage conversion circuit 20.

[0124] Furthermore, when the battery voltage of the battery VBAT is provided to the voltage conversion circuit 20, when the button 211 is pressed and turned on again, the node between the second switch tube 213 and the one-way diode 215 outputs a second switch signal (OFF) to the switch signal end of the main control circuit 11. The main control circuit 11 outputs a power-off signal to the control end of the third switch tube 214 according to the second switch signal to control the third switch tube 214 to turn off, and then the first switch tube 212 is turned off. The battery voltage of the battery VBAT cannot be provided to the voltage conversion circuit 20 until the button 211 is pressed and turned on again.

[0125] The button 211 , the first switch tube 212 , the second switch tube 213 , and the third switch tube 214 cooperate with the main control circuit 11 to control whether the battery voltage of the battery VBAT is provided to the voltage conversion circuit 20 . This not only simplifies the control logic but also has the advantage of high reliability.

[0126] As shown in FIG3-23, the driving circuit of the portable fan further includes a DC conversion circuit 22, which is used to receive the driving voltage (such as a DC voltage of 15V) and convert it into other DC working voltages, such as a DC working voltage of 3.3V and 5V.

[0127] Please refer to Figure 3-24. An embodiment of the present application also provides a portable fan 2, which includes a portable fan driving circuit 3, a DC brushless fan motor 4, and fan blades 5 driven by the DC brushless fan motor. The portable fan driving circuit 3 adopts the portable fan driving circuit described in any of the above embodiments.

[0128] Compared with the prior art, the driving circuit of the portable fan and the portable fan 2 in the above-mentioned embodiment, by using the main control circuit 11, the three-phase driving circuit 12, the reverse electromotive force detection circuit 14 and the DC brushless fan motor, can not only improve the energy-saving performance and control performance of the fan motor and thus improve the reliability of the driving circuit of the portable fan and the fan 2, but also extend the service life of the driving circuit of the portable fan and the fan 2. In addition, the use of the DC brushless fan motor makes the structure of the fan 2 simpler and the size smaller, which can improve the market competitiveness of the product.

[0129] Option 4, see Figures 4-1 to 4-11.

[0130] The present application discloses a handheld fan, wherein an air passage 11 is formed through an inner shell 1, and both sides of the air passage 11 are connected to an air inlet 23 and an air outlet 24, respectively. At least a portion of a fan assembly 3 is disposed in the air passage 11, and an outer shell 2 is disposed outside the inner shell 1. One side of a wiring opening 12 of the inner shell 1 faces the electrical connection portion of the fan assembly 3, and the other side of the wiring opening 12 faces the electrical connection portion of the handheld portion 5 of the handheld fan. The electrical connection portion of the fan assembly 3 is electrically connected to the electrical connection portion of the handheld portion 5 via a wire passing through the wiring opening 12. In this way, the wiring opening 12 of the inner shell 1 allows for the entry and exit of wires connected to the electrical connection portion of the fan assembly 3. The wires connected to the electrical connection portion of the fan assembly 3 pass through the wiring opening 12 at a position facing the electrical connection portion of the handheld portion 5 of the handheld fan, and then are connected to the electrical connection portion of the handheld portion 5 of the handheld fan. This helps to reduce the length of the wires, enhance durability, and improve the aesthetics of the wiring. Thereby achieving the technical effect of improving the stability of routing, enhancing the aesthetics of routing and enhancing durability.

[0131] Please refer to Figures 4-1 to 4-11. Figure 4-1 is a structural schematic diagram of a handheld fan provided in an embodiment of the present application. Figure 4-2 is a structural schematic diagram of a mounting bracket 6 in a handheld fan provided in an embodiment of the present application. Figure 4-3 is a structural schematic diagram of a handheld portion 5 in a handheld fan provided in an embodiment of the present application. Figure 4-4 is a structural schematic diagram of a wiring opening 12 in a handheld fan provided in an embodiment of the present application. Figure 4-5 is a structural schematic diagram of a wire groove 21 in a handheld fan provided in an embodiment of the present application. Figure 4-6 is a structural schematic diagram of a handheld fan provided in an embodiment of the present application. Schematic diagram of the structure of the middle wire trough 21. Figure 4-7 is a schematic diagram of the structure of the gear knob assembly 71 and the protection switch button assembly 72 of a handheld fan provided in an embodiment of the present application. Figure 4-8 is a schematic diagram of the structure of the inner shell 1 and outer shell 2 of a handheld fan provided in an embodiment of the present application. Figure 4-9 is a schematic diagram of the structure of the air inlet 23 and the air outlet 24 of a handheld fan provided in an embodiment of the present application. Figure 4-10 is a partial enlarged structural diagram of point A in Figure 4-9. Figure 4-11 is a schematic diagram of the structure of the fan assembly 3 of a handheld fan provided in an embodiment of the present application. A handheld fan provided in embodiment 1 of the present application includes an inner shell 1, an outer shell 2, and a fan assembly 3. The inner shell 1, outer shell 2, and fan assembly 3 are now described in detail:

[0132] For the inner shell 1, fan assembly 3 and outer shell 2:

[0133] The inner housing 1 is formed with an air passage 11, an air inlet 23 communicating with one side of the air passage 11, and an air outlet 24 communicating with the other side of the air passage 11. At least a portion of the fan assembly 3 is disposed in the air passage 11. The inner housing 1 has a wiring opening 12, one side of which faces the electrical connection portion of the fan assembly 3, and the other side of which faces the electrical connection portion of the handheld portion 5 of the handheld fan. The electrical connection portion of the fan assembly 3 is electrically connected to the electrical connection portion of the handheld portion 5 via a wire passing through the wiring opening 12. The handheld portion 5 has a mounting opening 4, which is connected to the outer housing 2, and the mounting opening 4 faces the other side of the wiring opening 12. The handheld fan provided in Example 1 of the present application may further include a mounting bracket 6 mounted on the handle portion 5, a second circuit board 73, and a gear knob assembly 71. At least a portion of the mounting bracket 6 is positioned within the mounting opening 4 and is connected to the inner housing 1. The mounting bracket 6 includes a space 61 for wiring. The electrical connection portion of the handle portion 5 includes a first circuit board 7, which is mounted on the mounting bracket 6 and plugs into the electrical connection portion of the fan assembly 3 via wiring. A second circuit board 73 is mounted on the mounting bracket 6 and plugs into the first circuit board 7 via wiring. The gear knob assembly 71 is mounted on the mounting bracket 6 and connected to the second circuit board 73. The second circuit board 73 and the first circuit board 7 are positioned opposite each other. The outer housing 2 is configured to cover the exterior of the inner housing 1. A baffle 22 is disposed on the inner housing 1, and the baffle 22 and the inner housing 1 together form a wire channel 21. At least a portion of the first circuit board 7 is disposed within the wire channel 21.

[0134] Specifically, the air passage 11 formed within the inner shell 1 is used for gas circulation. Gas enters the air passage 11 from the air inlet 23 and is then discharged from the air outlet 24. The outer shell 2 is disposed on the exterior of the inner shell 1. The inner shell 1 is provided with a wiring opening 12 for passing wires. The two sides of the wiring opening 12 are respectively opposite the electrical connection portion of the fan assembly 3 and the electrical connection portion of the handheld fan 5. The electrical connection portion of the fan assembly 3 can be a circuit board connected to the fan motor. The wires connected to the circuit board pass through the wiring opening 12 and are connected to the first circuit board 7 of the electrical connection portion of the handheld fan 5. The mounting opening 4 of the handheld portion 5 faces the wiring opening 12, and the accommodating space 61 of the mounting frame 6 communicates with the mounting opening 4 of the handheld portion 5. The first circuit board 7 and the second circuit board 73 are arranged opposite each other on the mounting frame 6. The wires passing through the wiring opening 12 can be plugged into the first circuit board 7 disposed on the mounting frame 6 after passing through the mounting opening 4 of the handheld portion 5. For example, one end of the wire passing through the wiring opening 12 can be plugged into the first circuit board 7 via a plug connector, thereby facilitating the connection or disconnection of the wires and the first circuit board 7. The second circuit board 73 is plugged into the first circuit board 7 via wires, such as when the second circuit board 73 is connected to the plug connector connected to the first circuit board 7 via wires, thereby facilitating the connection or disconnection of the second circuit board 73 and the first circuit board 7. The gear knob assembly 71, connected to the second circuit board 73, can be used to adjust the speed of the fan blades in the fan assembly 3, thereby controlling the wind speed. For example, rotating the knob in the gear knob assembly 71 adjusts the fan gear; pressing the knob in the gear knob assembly 71 allows the battery level of the battery 8 to be checked. A baffle 22 is provided near the handle 5 in the inner housing 1. The diameter of the inner housing 1 gradually increases from the air inlet 23 toward the air outlet 24, thereby forming an inwardly concave space at the end of the inner housing 1 near the air inlet 23. The baffle 22 can be arranged in the inwardly recessed space, and the inner shell 1 and the baffle 22 can enclose a wire groove 21. A portion of the first circuit board 7 can extend into the interior of the wire groove 21, and at the same time, the interior of the wire groove 21 has a space that can accommodate the wires connected to the first circuit board 7; or the entire first circuit board 7 is located outside the wire groove 21, a portion of the wire connected to the first circuit board 7 is located inside the wire groove 21, and the other part of the wire extends to the outside of the wire groove 21 and is connected to the first circuit board 7, which can improve the utilization of space.

[0135] The handheld fan provided in the first embodiment of the present application may further include a protection switch button assembly 72 and a battery 8. The protection switch button assembly 72 is disposed on the mounting bracket 6 and is electrically connected to the first circuit board 7. The battery 8 is disposed on the handheld portion 5 and is plugged into the first circuit board 7 via a wire.

[0136] Specifically, the battery 8 can be installed in the handheld portion 5 and connected to the first circuit board 7 via a wire. The battery 8 can power the fan assembly 3. The protection switch button assembly 72, which is electrically connected to the first circuit board 7, can control whether the circuit powered by the battery 8 is open or closed. If the protection switch button assembly 72 is a sliding switch, when the button in the protection switch button assembly 72 is slid to one end, the circuit is open, and the motor in the fan assembly 3 operates to drive the fan blades to rotate. When the button in the protection switch button assembly 72 is slid to the other end, the circuit is closed, and the motor in the fan assembly 3 does not operate and the fan blades do not rotate. This can prevent the operator from accidentally turning on the fan by accidentally touching the gear knob assembly 71.

[0137] The present application provides a handheld fan, wherein an air passage 11 is formed through an inner shell 1, and both sides of the air passage 11 are connected to an air inlet 23 and an air outlet 24, respectively. At least a portion of a fan assembly 3 is disposed in the air passage 11, and an outer shell 2 is disposed outside the inner shell 1. One side of a wiring opening 12 of the inner shell 1 faces the electrical connection portion of the fan assembly 3, and the other side of the wiring opening 12 faces the electrical connection portion of a handheld portion 5 of the handheld fan. The electrical connection portion of the fan assembly 3 is electrically connected to the electrical connection portion of the handheld portion 5 via a wire passing through the wiring opening 12. Thus, the wiring opening 12 of the inner shell 1 allows for the entry and exit of wires connected to the electrical connection portion of the fan assembly 3. The wires connected to the electrical connection portion of the fan assembly 3 pass through the wiring opening 12 at a position facing the electrical connection portion of the handheld portion 5 of the handheld fan, and are then connected to the electrical connection portion of the handheld portion 5 of the handheld fan. This helps to reduce the length of the wires, enhance durability, and improve the aesthetics of the wiring. Thereby achieving the technical effect of improving the stability of routing, enhancing the aesthetics of routing and enhancing durability.

[0138] In order to provide a detailed description of a handheld fan provided by the present application, the above embodiment 1 provides a detailed description of a handheld fan. Based on the same application concept, the present application also provides a handheld fan, see embodiment 2 for details.

[0139] A second embodiment of the present application provides a handheld fan.

[0140] The present application provides a handheld fan, wherein an air passage 11 is formed through an inner shell 1, and both sides of the air passage 11 are connected to an air inlet 23 and an air outlet 24, respectively. At least a portion of a fan assembly 3 is disposed in the air passage 11, and an outer shell 2 is disposed outside the inner shell 1. One side of a wiring opening 12 of the inner shell 1 faces the electrical connection portion of the fan assembly 3, and the other side of the wiring opening 12 faces the electrical connection portion of a handheld portion 5 of the handheld fan. The electrical connection portion of the fan assembly 3 is electrically connected to the electrical connection portion of the handheld portion 5 via a wire passing through the wiring opening 12. Thus, the wiring opening 12 of the inner shell 1 allows for the entry and exit of wires connected to the electrical connection portion of the fan assembly 3. The wires connected to the electrical connection portion of the fan assembly 3 pass through the wiring opening 12 at a position facing the electrical connection portion of the handheld portion 5 of the handheld fan, and are then connected to the electrical connection portion of the handheld portion 5 of the handheld fan. This helps to reduce the length of the wires, enhance durability, and improve the aesthetics of the wiring. Thereby achieving the technical effect of improving the stability of routing, enhancing the aesthetics of routing and enhancing durability.

[0141] Option 5, see Figures 5-1 to 5-6.

[0142] As shown in Figures 5-1 and 5-2, the portable fan includes a housing 1, a fan assembly 2, a motor 3, and a drive circuit board 4. The housing 1 is provided with an air inlet 161, a receiving cavity 162, and an air outlet 163, which are interconnected. The fan assembly 2, the motor 3, and the drive circuit board 4 are housed within the housing 1. The drive circuit board 4 is electrically connected to the motor 3 to drive the fan assembly 2 to rotate, blowing air from the air inlet 161 through the receiving cavity 162 and out of the air outlet 163.

[0143] As shown in Figures 5-1 and 5-2, the housing 1 includes a front housing 11 and a rear housing 12. The front housing 11 includes a first air housing 111 and a first handheld housing 112. The rear housing 12 includes a second air housing 121 and a second handheld housing 122. The first air housing 111 and the second air housing 121 form an air outlet 16, and the first handheld housing 112 and the second handheld housing 122 form a handheld portion 17. It should be understood that the first air housing 111 and the second air housing 121 can be arranged in a front-to-back or left-to-right manner; and the first handheld housing 112 and the second handheld housing 122 can be arranged in a front-to-back or left-to-right manner. The handheld portion 17 is provided with a switch 5, an interface 6, and a battery 7. In this embodiment, the switch 5 is a stepless speed control switch 5. Of course, in other embodiments, the first handheld housing 112 and the second handheld housing 122 may not be provided, or the fan may be provided in other common forms such as a desktop fan, a neck hanging fan, a clip fan, or a bracket fan.

[0144] As shown in Figures 5-2 to 5-4, the first air shell 111 comprises a first outer shell and a first inner shell that fit together. The first inner shell and the first outer shell are positioned in close contact, and both extend horizontally forward. The second air shell 121 comprises a second outer shell and a second inner shell that fit together. The rear ends of the second inner shell and the second outer shell are spaced apart and connected by a connector. The second outer shell extends horizontally forward. The second inner shell extends horizontally forward from the rear to the front, then expands radially outward. The front end of the second inner shell is connected to the front end of the second outer shell, and the front end of the second inner shell abuts the rear end of the first inner shell. In this embodiment, the first and second outer shells are integrally formed. However, in other embodiments, the first and second outer shells may be formed separately. Both the first and second air shells 111 and 121 have a double-layer shell 1 structure, which provides a more stable structure. The shape of the second inner shell facilitates wind pressure treatment, making the wind more powerful and discharging farther. In other embodiments, the first air shell 111 and / or the second air shell 121 may also have a single-layer shell 1 structure.

[0145] As shown in Figures 5-1 and 5-2, the housing 1 further includes a pressure member 13 disposed within the first air housing 111. A plurality of connecting blades 14 connect the pressure member 13 and the front housing 11. A base 131 and a sleeve 132 are formed within the pressure member 13. The base 131 is located between the front and rear ends of the pressure member 13 and forms a rearward clearance space 1321 within the pressure member 13. The base 131 forms a forward receiving portion 1322 within the pressure member 13. The sleeve 132 protrudes from the base 131 toward the accommodating cavity 162, that is, the sleeve 132 protrudes rearward from the base 131 and is hollow.

[0146] As shown in Figures 5-1 and 5-2, the air inlet 161 is located in the radially inner area of ​​the second inner shell, and the air outlet 163 is located in the radial area between the pressure member 13 and the first inner shell. The fan assembly 2 includes a hub 21 and a plurality of blades 22 spaced apart on the outer surface of the hub 21. The hub 21 includes a wind guide surface 212 that radially increases from back to front. The pressure member 13 includes a pressure surface 133 that radially increases from back to front. The wind guide surface 212 and the pressure surface 133 are spaced closely together so that the wind blows smoothly forward. A radially outward wind duct is formed from the air inlet 161 to the air outlet 163, so that the wind is pressurized in the shell 1 and a larger wind outlet surface is formed.

[0147] As shown in Figures 5-1 to 5-4, the fan assembly 2 includes the hub 21 and a plurality of blades 22 spaced apart on the outer surface of the hub 21. A rotating shaft 23 is fixed to the center of the inner side of the hub 21. The motor 3 includes a stator 31 and a rotor 32, both of which are accommodated in the hub 21. Furthermore, the hub 21 includes a ring-shaped extension wall 211, and both the stator 31 and the rotor 32 are accommodated in the extension wall 211. The stator 31 is sleeved outside the sleeve 132 and includes a coil 311. The rotor 32 is radially arranged between the stator 31 and the hub 21. The rotating shaft 23 is inserted into the sleeve 132, and the extension wall 211, the stator 31, and the rotor 32 extend forward into the clearance space 1321.

[0148] As shown in Figures 5-1 and 5-2, the extension wall 211 extends forward beyond the air guide surface 212. The air guide surface 212 and the pressure surface 133 are closely spaced. Therefore, the gap between the air guide surface 212 and the pressure surface 133 is offset from the front end of the extension wall 211, making it difficult for dust to enter and settle within the extension wall 211. The stator 31 and the rotor 32 do not extend forward beyond the extension wall 211. Instead, the extension wall 211, the stator 31, and the rotor 32 extend forward into the clearance space 1321, so that the extension wall 211, the stator 31, and the rotor 32 are partially accommodated within the clearance space 1321.

[0149] As shown in Figures 5-1 and 5-2, the driver circuit board 4 is not positioned between the base 131 and the stator 31. The battery 7 is electrically connected to the driver circuit board 4, which is in turn electrically connected to the leads of the coil 311 to drive the fan assembly 2 to rotate, blowing air from the air inlet 161 through the accommodating cavity 162 and out the air outlet 163. In this embodiment, the driver circuit board 4 is housed in the accommodating portion 1322 formed forwardly of the base 131. The front end of the pressure member 13 also includes a front cover 15, which is disposed at the front end of the accommodating portion 1322 and is recessed rearwardly to form a negative pressure zone 151. The provision of the front cover 15 not only covers the accommodating portion 1322, shielding and protecting the driver circuit board 4, but also allows the negative pressure zone 151 formed by the rearward recess of the front cover 15 to compensate for air flow to the air outlet 163, thereby increasing the air volume at the air outlet 163.

[0150] As shown in Figures 5-1 to 5-4, in this embodiment, the motor 3 is a three-phase motor, and the coil 311 includes twelve windings. This large number of windings limits the internal space of the motor 3. By not locating the driver circuit board 4 between the base 131 and the stator 31, the electrical connection between the leads of the coil 311 and the driver circuit board 4 is simplified and convenient. Furthermore, the space between the base 131 and the stator 31 can be further reduced, resulting in a more rational internal space distribution within the portable fan, thereby achieving miniaturization of the portable fan.

[0151] Figure 5-5 is a schematic diagram of an embodiment of the portable fan of the present application. The main difference from the previous embodiment is that the driver circuit board 4 is housed in the handle 17 and located between the switch 5 and the interface 6. The switch 5 is connected to the driver circuit board 4, and the interface 6 is connected to the driver circuit board 4. The rest of the structure and performance are essentially the same as those of the first embodiment and will not be further described here.

[0152] Figures 5-6 are schematic diagrams of an embodiment of the portable fan of this application. The main difference from the previous embodiment is that the driver circuit board 4 is housed within the handle 17 and located below the battery 7. The remaining structure and performance are essentially the same as those of the first embodiment and will not be further described here.

[0153] The above is only a preferred embodiment of the present application and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A portable fan, wherein: include: The air duct portion comprises a main body, an air guide cavity is arranged inside the main body, an air outlet and an air inlet are arranged at opposite ends of the air duct portion, the air outlet and the air inlet are both connected to the air guide cavity, and a positioning boss is arranged inside the main body; The blowing part includes a rotating fan blade and a driving part drivingly connected to the rotating fan blade, wherein the rotating fan blade is rotatably installed in the air guide cavity and arranged toward the air outlet; the driving part includes a stator and a rotor sleeved outside the stator, wherein the rotor is fixedly installed on the rotating fan blade and is coaxially arranged with the rotating fan blade, and the stator is fixedly sleeved on the positioning boss; A handheld part is connected to the air duct part, a mounting cavity is provided in the handheld part, a power supply component is installed in the mounting cavity, and the power supply component is electrically connected to the driving part.

2. The portable fan according to claim 1, wherein: The main body includes a first shell and a second shell, the first shell is connected to the second shell, the air guide cavity is formed between the first shell and the second shell, the first shell is provided with the air inlet, the second shell is provided with the air outlet, the second shell is provided with the positioning boss, and the positioning boss extends along the extension direction of the air guide cavity.

3. The portable fan according to claim 1, wherein: The rotating fan blade is provided with a fixing hole, the axis of the fixing hole is collinear with the axis of the rotating fan blade, the blowing part further comprises a rotating shaft, the first end of the rotating shaft is fixedly inserted into the fixing hole; the positioning boss is provided with a positioning hole inside, the axis of the positioning hole is collinear with the axis of the rotating shaft, and the second end of the rotating shaft is rotatably inserted into the positioning hole; The blowing part also includes a bearing part, the outer ring of the bearing part is fixed in the positioning hole, and the inner ring of the bearing part is sleeved on the second end of the rotating shaft; the bearing part includes a rolling bearing, and the blowing part also includes a limiter, the limiter is installed on the second end of the rotating shaft, and the bearing part is located between the limiter and the first end of the rotating shaft; there are multiple bearing parts, and an inner flange is provided on the inner side wall of the positioning hole, and the inner flange is arranged between two adjacent bearing parts so that the two adjacent bearing parts are arranged at intervals; the bearing part includes a sliding bearing, and the blowing part also includes two sealing rings, both of which are sleeved on the rotating shaft and are respectively located on both sides of the sliding bearing.

4. The portable fan according to claim 2, wherein: The hand-held part includes a third shell and a fourth shell, the third shell is connected to the fourth shell, and the installation cavity is formed between the third shell and the fourth shell; the first shell includes a main body and an air duct lining, the air duct lining is installed on the main body, an air duct is arranged inside the air duct lining, and the air guide cavity is formed between the air duct lining and the second shell.

5. The portable fan according to claim 2, wherein: The driving part is a three-phase motor; a charging port is provided on the handheld part, and the charging port is electrically connected to the power supply component; and / or the air duct part and the handheld part are fixedly connected or pivotally connected so as to be relatively rotatable.

6. The portable fan according to claim 1, wherein: The control circuit of the portable fan comprises: A charging and power supply circuit, used to electrically connect an external power source and a power supply component to receive an external voltage to charge the power supply component and output a power supply voltage; A fan driving circuit, electrically connected to the charging and power supply circuit and the rotating fan blades, and used to drive the rotating fan blades to rotate; a control switch, wherein the control end of the control switch is used to receive the external voltage and is grounded, the first conduction end of the control switch is used to electrically connect the power supply component to receive the output voltage of the power supply component, the second conduction end of the control switch is used to electrically connect to the fan drive circuit, the control switch is closed when receiving the external voltage, and is turned on when not receiving the external voltage; and The main control circuit is electrically connected to the charging and power supply circuit, the fan driving circuit and the control switch.

7. The portable fan according to claim 6, wherein: The charging and power supply circuit includes a charging port and a charging management chip. The power supply end of the charging port receives the external voltage and is electrically connected to the charging input pin of the charging management chip. The power supply end of the charging port is also electrically connected to the negative electrode of the Zener diode, and the positive electrode of the Zener diode is grounded. The switch pin of the charging management chip is used to electrically connect the positive electrode of the power supply component via a first inductor. The boost output pin of the charging management chip is used to output the supply voltage. The boost input pin of the charging management chip is connected to the node between the power supply component and the first inductor via a first connection resistor on the one hand, and is grounded via a first grounding capacitor on the other hand.

8. A driving circuit for a portable fan, wherein: include: Main control circuit; A three-phase drive circuit, comprising at least three signal input terminals and three drive signal output terminals, wherein the at least three signal input terminals are respectively electrically connected to the main control circuit to respectively receive control signals, and the three drive signal output terminals are used to electrically connect to three signal terminals of a brushless DC fan motor to respectively output three-phase drive signals to drive the brushless DC fan motor to rotate; as well as A reverse electromotive force detection circuit comprises three detection branches, each detection branch comprises a detection end and a detection output end electrically connected to the detection end, the three detection ends of the three detection branches are electrically connected to the three drive signal output ends, respectively, and the three detection output ends of the three detection branches are electrically connected to the main control circuit, so as to respectively output a first detection signal, a second detection signal and a third detection signal to the main control circuit, so that the main control circuit obtains the phase of the three-phase drive signal according to the first detection signal, the second detection signal and the third detection signal to adjust the control signal.

9. The driving circuit of the portable fan according to claim 8, wherein: The detection branch includes a first detection resistor, a second detection resistor and a third detection resistor, the first detection resistor and the second detection resistor are connected in series, and an end of the first detection resistor away from the second detection resistor is a detection end, an end of the second detection resistor away from the first detection resistor is grounded, and a node between the first detection resistor and the second detection resistor is the detection output end.

10. The driving circuit of the portable fan according to claim 8, wherein: The three-phase drive circuit includes a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, a sixth transistor, a seventh transistor, an eighth transistor and a ninth transistor, wherein the first conduction ends of the first transistor, the second transistor and the third transistor are all connected to a power supply end, the first conduction end of the fourth transistor is connected to the power supply end, the first conduction end of the fifth transistor is connected to the power supply end, the first conduction end of the sixth transistor is connected to the power supply end, the control ends of the fourth transistor, the fifth transistor and the sixth transistor are respectively electrically connected to the main control circuit, the control ends of the seventh transistor, the eighth transistor and the ninth transistor are respectively electrically connected to the control ends of the fourth transistor, the fifth transistor and the sixth transistor for receiving the control signal, the second conduction ends of the fourth transistor, the fifth transistor and the sixth transistor are all grounded, the first conduction end of the seventh transistor is connected to the second conduction end of the first transistor, The second conduction end of the seventh transistor is grounded, the first conduction end of the eighth transistor is connected to the second conduction end of the second transistor, the second conduction end of the eighth transistor is grounded, the first conduction end of the ninth transistor is connected to the second conduction end of the third transistor, the second conduction end of the ninth transistor is grounded, and the node between the first conduction end of the seventh transistor and the second conduction end of the first transistor, the node between the first conduction end of the eighth transistor and the second conduction end of the second transistor, and the node between the first conduction end of the ninth transistor and the second conduction end of the third transistor are respectively used as three drive signal output ends; the at least three signal input ends are three PWM signal input ends, and the control signal includes three PWM signals; the fan driving circuit also includes a current detection circuit, the second conduction ends of the seventh transistor, the eighth transistor, and the ninth transistor are all grounded via the current detection circuit, and the current detection circuit is also electrically connected to the main control circuit; The current detection circuit includes a sensing resistor and a sensing capacitor. The second conduction ends of the seventh transistor, the eighth transistor, and the ninth transistor are grounded via the sensing resistor and the sensing capacitor in sequence. A node between the sensing resistor and the sensing capacitor is electrically connected to the main control circuit.

11. The driving circuit of the portable fan according to claim 8, wherein: The three-phase drive circuit includes a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, and a sixth transistor. The first conduction ends of the first transistor, the second transistor, and the third transistor are all connected to the power supply end. The first conduction end of the fourth transistor is connected to the second conduction end of the first transistor. The first conduction end of the fifth transistor is connected to the second conduction end of the second transistor. The first conduction end of the sixth transistor is connected to the second conduction end of the third transistor. The node between the first conduction end of the fourth transistor and the second conduction end of the first transistor, the node between the first conduction end of the fifth transistor and the second conduction end of the second transistor, and the node between the first conduction end of the sixth transistor and the second conduction end of the third transistor are respectively used as three drive signal output ends. The control ends of the first transistor, the second transistor, the third transistor, the fourth transistor, the fifth transistor, and the sixth transistor are respectively used to electrically connect to the main control circuit to receive the control signal; the control signal includes six PWM signals.

12. [Corrected 18.02.2024 as per Rule 91] A driving circuit for a portable fan according to claim 11, wherein: The fan driving circuit further comprises a current detection circuit, the second conduction end of the sixth transistor is grounded via the current detection circuit, and the current detection circuit is also electrically connected to the main control circuit; The current detection circuit includes a sensing resistor and a sensing capacitor, the second conduction end of the sixth transistor is grounded via the sensing resistor, the sensing capacitor is connected in parallel with the sensing resistor, and a node between the sensing resistor and the second conduction end of the sixth transistor is electrically connected to the main control circuit; The current detection circuit also includes a first series resistor, a second series resistor, and a parallel resistor, the parallel resistor is connected in parallel with the sensing resistor, the first series resistor is connected between one end of the sensing capacitor and one end of the sensing resistor, and the second series resistor is connected between the other end of the sensing capacitor and the other end of the sensing resistor.

13. The driving circuit of the portable fan according to claim 12, wherein: The main control circuit includes a main control chip and three three-phase control chips, each of which is electrically connected to the main control chip and the three-phase drive circuit. The fan drive circuit also includes a voltage conversion circuit, which is used to receive a battery voltage and convert the battery voltage into a drive voltage and provide the drive voltage to the power supply end of the three three-phase control chips. The main control chip is used to output a main control signal to the three three-phase control chips, so that the three three-phase control chips respectively output the control signal to the three-phase drive circuit; the fan drive circuit also includes a switch control circuit, which is electrically connected to the battery, the voltage conversion circuit and the main control circuit, and is used to control the operation of the voltage conversion circuit. The circuit includes a button, a first switch tube, a second switch tube and a third switch tube, the two conduction ends of the first switch tube are respectively connected to the positive electrode of the battery and the input end of the voltage conversion circuit, the control end of the first switch tube is grounded via the two conduction ends of the third switch tube, the positive electrode of the battery is also connected to the control end of the third switch tube via the two conduction ends of the second switch tube and a unidirectional diode, the control end of the second switch tube is grounded via the button, the control end of the third switch tube is electrically connected to the main control circuit, and the node between the second switch tube and the unidirectional diode is also electrically connected to the main control circuit; the fan drive circuit also includes a DC conversion circuit, which is used to receive the drive voltage and convert it into other DC working voltages.

14. [Corrected 18.02.2024 as per Rule 91] A driving circuit for a portable fan according to claim 8, wherein: The fan driving circuit includes a battery voltage detection circuit, the battery voltage detection circuit includes a second voltage-dividing resistor and a third voltage-dividing resistor connected in series, and a node between the second voltage-dividing resistor and the third voltage-dividing resistor is electrically connected to the main control circuit; or the battery voltage detection circuit includes a filter capacitor and a sampling resistor connected in series, the sampling resistor is connected between the filter capacitor and ground, and a node between the filter capacitor and the sampling resistor is electrically connected to the main control circuit, the fan driving circuit also includes a signal amplification circuit, the node between the filter capacitor and the sampling resistor is connected to the main control circuit via the signal amplification circuit, and the signal amplification circuit is used to amplify the signal of the node and provide the amplified signal to the main control circuit; The fan drive circuit also includes a Hall detection circuit, which is electrically connected to the main control circuit and is used to detect the magnetic field generated by the DC brushless fan motor and output a Hall detection signal to the main control circuit, so that the main control circuit can obtain the position of the rotor of the DC brushless fan motor according to the Hall detection signal; the Hall detection circuit also includes a motor temperature detection element, which is connected between the Hall element of the Hall detection circuit and the main control circuit; the fan drive circuit also includes a transistor temperature detection circuit, which includes a first voltage-dividing resistor and a thermistor connected in series, and the thermistor is used to sense the temperature of each transistor of the three-phase drive circuit, and the node between the first voltage-dividing resistor and the thermistor is electrically connected to the main control circuit and is used to output a temperature signal, so that the main control circuit controls whether the fan drive circuit enters a temperature protection state according to the temperature signal; the thermistor is connected between the first voltage-dividing resistor and ground, and the transistor temperature detection circuit also includes a voltage-stabilizing capacitor connected in parallel with the thermistor.

15. The driving circuit of the portable fan according to claim 8, wherein: The fan drive circuit also includes a main control circuit including a main control chip and an auxiliary chip. The number of the three-phase drive circuit, the reverse electromotive force detection circuit and the DC brushless fan motor are all two and one-to-one corresponding. The main control chip is electrically connected to one of the three-phase drive circuits to output the control signal to one of the three-phase drive circuits to drive a corresponding DC brushless fan motor. The reverse electromotive force detection circuit is electrically connected to the corresponding three-phase drive circuit and outputs the corresponding first detection signal, the second detection signal and the third detection signal to the main control chip, so that the main control chip can know the three-phase of the three-phase drive circuit. The phase of the driving signal is used to adjust the control signal output to one of the three-phase driving circuits; the auxiliary chip is electrically connected to another of the three-phase driving circuits to output the control signal to another of the three-phase driving circuits to drive another corresponding DC brushless fan motor; another of the reverse electromotive force detection circuits is electrically connected to the corresponding three-phase driving circuit and outputs the corresponding first detection signal, the second detection signal and the third detection signal to the auxiliary chip, so that the auxiliary chip learns the phase of the three-phase driving signal of another of the three-phase driving circuits to adjust the control signal output to another of the three-phase driving circuits.

16. A handheld fan, wherein: include: An inner shell, an outer shell and a fan assembly, the inner shell is formed with an air passage, an air inlet connected to one side of the air passage and an air outlet connected to the other side of the air passage, at least a portion of the fan assembly is arranged in the air passage, the outer shell is used to cover the outside of the inner shell, the inner shell has a wiring opening, one side of the wiring opening is opposite to the electrical connection part of the fan assembly, and the other side of the wiring opening is used to face the electrical connection part of the handheld part of the handheld fan, the electrical connection part of the fan assembly is electrically connected to the electrical connection part of the handheld part through a wire passing through the wiring opening.

17. The handheld fan according to claim 16, wherein: The handheld part has a mounting opening, the handheld part is connected to the housing, and the mounting opening is directly opposite to the other side of the wiring opening; The handheld fan further comprises a mounting frame arranged on the handheld portion, at least a portion of the mounting frame is arranged in the mounting opening, the mounting frame is connected to the inner shell, and the mounting frame has an accommodation space for the wire to pass through; The electrical connection part of the handheld part includes: a first circuit board, the first circuit board is arranged on the mounting frame, and the first circuit board is plugged with the electrical connection part of the fan assembly through the wire.

18. The handheld fan according to claim 17, wherein: It also includes a second circuit board and a gear knob assembly, wherein the second circuit board is arranged on the mounting frame, and the second circuit board is plugged with the first circuit board through a wire; the gear knob assembly is arranged on the mounting frame, and the gear knob assembly is connected with the second circuit board; the second circuit board and the first circuit board are arranged oppositely; It also includes a protection switch button assembly, which is arranged on the mounting frame and is electrically connected to the first circuit board.

19. The handheld fan according to claim 17, wherein: It also includes a battery, which is arranged on the handheld part and plugged into the first circuit board through the wire.

20. The handheld fan according to claim 17, wherein: The inner shell is provided with a baffle, and the baffle and the inner shell are enclosed to form a wire accommodating groove; At least a portion of the first circuit board is disposed in the wire accommodating groove.

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