Motor driving circuit, PCB and motor
By designing a three-phase H-bridge circuit unit and a drive unit, the problems of dust accumulation in the cooling fan in dusty environments and the safety of the drive circuit were solved. This enabled smooth switching between forward and reverse rotation of the motor and efficient heat dissipation, thereby improving system safety and heat dissipation efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- 品岱电子(江苏)股份有限公司
- Filing Date
- 2025-04-29
- Publication Date
- 2026-05-19
AI Technical Summary
Existing cooling fans are prone to dust accumulation in dusty environments, leading to decreased heat dissipation efficiency. Furthermore, traditional drive circuits pose a risk of short circuits, have poor heat dissipation and mechanical stability, and are limited in compatibility and expandability.
A three-phase H-bridge circuit unit and a drive unit are adopted, combined with a current limiting circuit and an RC buffer circuit, to achieve smooth switching between forward and reverse rotation of the motor. The U, V, and W three mutually complementary drive signals work together to form a continuous current path, which enhances heat dissipation and mechanical stability.
It achieves smooth switching between forward and reverse rotation of the motor, reduces energy loss, improves heat dissipation efficiency and mechanical stability, avoids short circuit risks, and is suitable for dust removal and heat dissipation scenarios with frequent forward and reverse rotation.
Smart Images
Figure CN224264875U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to a motor drive circuit, a PCB board, and a motor, belonging to the field of motor technology. Background Technology
[0002] Cooling fans are key components widely used in electronic equipment and industrial devices. During long-term operation, dust accumulation can reduce their heat dissipation efficiency and even cause overheating failures. Traditional cooling fans mostly use a unidirectional rotation mode. Although they can achieve basic heat dissipation through airflow, dust easily adheres to the blade surface and is difficult to remove automatically. Especially in dusty environments, dust accumulation can significantly reduce fan airflow and shorten its service life.
[0003] In existing technologies, some solutions attempt to alleviate the dust accumulation problem by improving the shape of fan blades or adding filters. However, such solutions can only slow down the dust adhesion speed and cannot achieve active dust removal. Furthermore, filters increase airflow resistance, further affecting heat dissipation performance.
[0004] A few solutions propose using a motor to drive a fan to periodically rotate in the opposite direction to shake off dust, but these solutions have the following problems in practical applications:
[0005] Insufficient circuit safety: Traditional single-phase or simple H-bridge drive circuits are prone to momentary conduction of the upper and lower bridge arms during forward and reverse switching, leading to short circuit risk and damage to switching devices (such as MOSFETs).
[0006] Poor heat dissipation and mechanical stability: The PCB layout of the drive circuit is not optimized for the heat generated by high-frequency switching, and the heat dissipation area is insufficient. Long-term operation is prone to aging of components or cracking of solder joints due to excessive temperature rise.
[0007] Limited compatibility and scalability: The circuit design relies on complex control logic or external sensors, making it difficult to adapt to the needs of motors with different power levels, and the maintenance cost is high. Summary of the Invention
[0008] The purpose of this invention is to overcome the shortcomings of the prior art and provide a motor drive circuit, PCB board and motor that can achieve smooth switching between forward and reverse rotation of the motor and drive the fan blades to rotate in the opposite direction periodically, so as to remove accumulated dust from the blade surface and maintain the long-term efficient heat dissipation of the fan.
[0009] To achieve the above objectives, this utility model employs the following technical solution:
[0010] In a first aspect, this utility model provides a motor drive circuit, including: a three-phase H-bridge circuit unit and a drive unit;
[0011] The three-phase H-bridge circuit unit includes a U-phase H-bridge circuit, a V-phase H-bridge circuit and a W-phase H-bridge circuit. Each phase H-bridge circuit includes an upper bridge arm switch and a lower bridge arm switch.
[0012] In the U-phase H-bridge circuit, the drain of the upper arm switch is connected to the positive terminal of the power supply, and the source is connected to the CON point of the U-phase. The drain of the lower arm switch is connected to the CON point of the U-phase, and the source is grounded. In the V-phase H-bridge circuit, the drain of the upper arm switch is connected to the positive terminal of the power supply, and the source is connected to the CON point of the V-phase. The drain of the lower arm switch is connected to the CON point of the V-phase, and the source is grounded. In the W-phase H-bridge circuit, the drain of the upper arm switch is connected to the positive terminal of the power supply, and the source is connected to the CON point of the W-phase. The drain of the lower arm switch is connected to the CON point of the W-phase, and the source is grounded.
[0013] The driving unit includes 6 driving signal lines, which are respectively connected to the gates of the switching transistors of each phase H-bridge circuit, and are used to switch the conduction level of each phase and each bridge arm switching transistor according to the chip signal.
[0014] In conjunction with the first aspect, optionally, the switching transistor in the three-phase H-bridge circuit unit is an N-channel MOSFET.
[0015] In conjunction with the first aspect, optionally, the driving signals of the upper bridge arm switch and the lower bridge switch of each phase H-bridge circuit in the three-phase H-bridge circuit unit are complementary logic signals, and a dead time is provided between the driving signals of the upper bridge arm switch and the driving signals of the lower bridge switch.
[0016] In conjunction with the first aspect, optionally, the three-phase H-bridge circuit unit further includes a current limiting circuit, one end of which is connected to the drain of the lower bridge arm switching transistor of each phase H-bridge circuit, and the other end is grounded.
[0017] In conjunction with the first aspect, optionally, the three-phase H-bridge circuit unit further includes multiple RC snubber circuits, which are connected in parallel between the drain and source of each switching transistor to absorb voltage spikes during the switching process of the switching transistor.
[0018] Secondly, this utility model provides a PCB board on which the motor drive circuit described in the first aspect is printed.
[0019] In conjunction with the second aspect, optionally, it includes:
[0020] The hollow area is located in the middle of the PCB board to enhance heat dissipation and mechanical stability;
[0021] The pads are arranged in a ring around the periphery of the empty area and are used to connect the motor drive circuit to the motor.
[0022] In conjunction with the second aspect, optionally, the pad group includes a COM pad, a U-phase pad, a V-phase pad, a W-phase pad, and a ground pad;
[0023] One end of the COM pad is connected to the U-phase CON point, V-phase CON point and W-phase CON point in the motor drive circuit, and the other end is connected to the U-phase pad, V-phase pad and W-phase pad.
[0024] The U-phase pad, V-phase pad, and W-phase pad are respectively connected to the output pins of the U, V, and W phase windings of the motor.
[0025] The grounding pad is used to connect the source of each phase lower bridge arm switch transistor in the motor drive circuit to the ground wire.
[0026] It also includes a stator pin interface, which is located on the surface of the PCB board and connected to the grounding pad.
[0027] Thirdly, this utility model provides an electric motor, which operates using the motor drive circuit described in the first aspect.
[0028] Compared with the prior art, the beneficial effects achieved by the motor drive circuit, PCB board and motor provided by the present invention include:
[0029] This invention provides a motor drive circuit comprising a three-phase H-bridge circuit unit and a drive unit. The three-phase H-bridge circuit unit includes a U-phase H-bridge circuit, a V-phase H-bridge circuit, and a W-phase H-bridge circuit. Each phase H-bridge circuit includes an upper bridge arm switch and a lower bridge arm switch. The three-phase H-bridge circuit provides a continuous and balanced current path formed by the complementary drive signals of U, V, and W phases. This reduces energy loss caused by current discontinuity in single-phase drive, while improving the smoothness of motor torque output and reducing operating noise and vibration. It is suitable for dust removal and heat dissipation scenarios requiring frequent forward and reverse rotation. The three-phase drive mode reduces energy loss, optimizes torque output smoothness, and improves overall energy efficiency.
[0030] The driving unit provided by this utility model includes 6 driving signal lines, which are respectively connected to the gates of the switching transistors of each phase H-bridge circuit. They are used to switch the conduction level of each phase and each bridge arm switching transistor according to the chip signal. The driving unit provided by this utility model can realize the smooth switching of the motor forward and reverse rotation, avoid the short circuit risk caused by the simultaneous conduction of the upper and lower bridge arms, and improve the system safety and response efficiency.
[0031] The PCB board provided by this utility model includes a hollowed-out area and a pad group. The hollowed-out area is located in the middle of the PCB board to enhance heat dissipation and mechanical stability. This utility model can increase the heat dissipation area and optimize airflow distribution through the hollowed-out area, significantly improving heat dissipation efficiency. At the same time, the structural reinforcement reduces the risk of deformation caused by thermal expansion or vibration. The pad group is distributed in a ring around the periphery of the hollowed-out area to realize the connection between the motor drive circuit and the motor. This utility model simplifies the physical connection between the motor and the drive circuit through the reasonable layout of the pad group, reducing wiring complexity and installation errors.
[0032] This invention uses a motor that rotates in both forward and reverse directions to drive the fan blades to rotate periodically in the opposite direction. The change in airflow direction generates a vibration effect, which causes accumulated dust to detach from the blade surface, thus maintaining the fan's long-term efficient heat dissipation.
[0033] The three-phase drive mode reduces energy loss, optimizes torque output smoothness, and improves overall energy efficiency;
[0034] This invention significantly improves safety during forward / reverse switching, heat dissipation efficiency, dust removal effect, and structural reliability, and is especially suitable for dust removal and cooling fan scenarios that require long-term stable operation. Attached Figure Description
[0035] Figure 1 This is a schematic diagram of the structure of a three-phase H-bridge circuit unit in a motor drive circuit provided in Embodiment 1 of this utility model;
[0036] Figure 2 This is a schematic diagram of the structure of a PCB board provided in Embodiment 2 of this utility model.
[0037] In the diagram: 1. Empty area; 2. COM pad; 3. U phase pad; 4. V phase pad; 5. W phase pad; 6. Ground pad. Detailed Implementation
[0038] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0039] In the description of this utility model, it should be noted that the terms "upper / lower end," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0040] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "set / set up," "sleeve," "connection," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.
[0041] Example 1:
[0042] This embodiment provides a motor drive circuit, including: a three-phase H-bridge circuit unit and a drive unit.
[0043] like Figure 1 As shown, the three-phase H-bridge circuit unit includes a U-phase H-bridge circuit, a V-phase H-bridge circuit, and a W-phase H-bridge circuit. Each phase H-bridge circuit includes an upper bridge arm (UH, VH, and WH in the figure) and a lower bridge arm (UL, VL, and WL in the figure). Each bridge arm is equipped with a switching transistor.
[0044] In this embodiment, the switching transistors in the three-phase H-bridge circuit unit are N-channel MOSFETs.
[0045] like Figure 1 As shown, in the U-phase H-bridge circuit, the drain of the upper arm switch Q1 is connected to the positive terminal of the power supply, and the source is connected to the U-phase CON point. The drain of the lower arm switch Q2 is connected to the U-phase CON point, and the source is grounded. In the V-phase H-bridge circuit, the drain of the upper arm switch Q3 is connected to the positive terminal of the power supply, and the source is connected to the V-phase CON point. The drain of the lower arm switch Q4 is connected to the V-phase CON point, and the source is grounded. In the W-phase H-bridge circuit, the drain of the upper arm switch Q5 is connected to the positive terminal of the power supply, and the source is connected to the W-phase CON point. The drain of the lower arm switch Q6 is connected to the W-phase CON point, and the source is grounded.
[0046] The three-phase H-bridge circuit unit also includes a current limiting circuit. One end of the current limiting circuit is connected to the drain of the switching transistor of the lower arm of each phase H-bridge circuit, and the other end is grounded.
[0047] In this embodiment, as Figure 1 As shown, the current limiting circuit includes current limiting resistor R29 and current limiting resistor R30.
[0048] It should be noted that in some application scenarios, only current-limiting resistor R29 or current-limiting resistor R30 is used.
[0049] The current limiting circuit is based on the resistance characteristics P=U*I and P=I 2 *R, which achieves current limiting through grounding.
[0050] In actual circuit design, based on the current application current and peak current of the current product, select appropriate wattage and resistance values of resistors to achieve the ideal current limiting effect.
[0051] The design of current limiting circuits can limit the impact of abnormal current on the circuit, improve anti-interference ability and operational stability.
[0052] The three-phase H-bridge circuit unit also includes multiple RC snubber circuits, which are connected in parallel between the drain and source of each switching transistor to absorb voltage spikes during the switching process.
[0053] like Figure 1 As shown, the RC snubber circuit set on the upper arm of the U-phase H-bridge circuit includes R1 and C1, and the RC snubber circuit set on the lower arm of the U-phase H-bridge circuit includes R5 and C5.
[0054] like Figure 1 As shown, the RC buffer circuit set on the upper arm of the Y-phase H-bridge circuit includes R11 and C8, and the RC buffer circuit set on the lower arm of the V-phase H-bridge circuit includes R16 and C10.
[0055] like Figure 1 As shown, the RC snubber circuit on the upper arm of the W-phase H-bridge circuit includes R19 and C11, and the RC snubber circuit on the lower arm of the W-phase H-bridge circuit includes R28 and C14.
[0056] It should be noted that, Figure 1 The R and C used in the RC snubber circuit are designed according to the circuit principle. The details of the RC snubber circuit need to be adjusted according to the actual current and voltage of the line in the specific application scenario, and the specifications of the components used need to be confirmed.
[0057] As a further improvement, such as Figure 1As shown, transistors Q6, Q8, and Q11 are also installed on the three-phase H-bridge circuit unit. These transistors are connected to the upper arm of each phase of the H-bridge circuit. They perform signal amplification, level conversion, and isolation protection functions in the circuit, enhancing the current and voltage capabilities of the drive signal to ensure the efficient and reliable operation of the N-channel MOSFETs, while reducing system complexity and cost.
[0058] In this embodiment, the transistor is model MMBT5551.
[0059] The RC snubber circuit added to each phase of the H-bridge circuit can directly absorb voltage spikes during the switching process of the switching transistor, reduce device stress, and extend the service life of the MOSFET.
[0060] The drive unit includes six drive signal lines (UH, UL, VH, VL, WH, and WL in this embodiment). These six drive signal lines are connected to the gates of the switching transistors in each phase of the H-bridge circuit, and are used to switch the conduction level of each phase and each bridge arm switching transistor according to the chip signal.
[0061] It should be noted that the drive signals of the upper and lower bridge switch transistors in each phase of the H-bridge circuit are complementary logic signals, and there is a dead time between the drive signals of the upper and lower bridge switch transistors.
[0062] Driven by the drive signal, the motor runs when the upper arm of any one phase and the lower arm of another phase are simultaneously turned on.
[0063] Furthermore, under the drive signal, when the upper and lower bridge arms that are simultaneously turned on at any running time t are different from the upper and lower bridge arms that were simultaneously turned on at the previous running time t-1, the direction of motor rotation changes.
[0064] The drive unit periodically switches the conduction phase of the three-phase H-bridge by using a preset drive signal timing (without the need for an external controller).
[0065] For example:
[0066] Forward rotation phase: The upper arm switch Q1 of the U-phase H-bridge circuit and the lower arm switch Q4 of the V-phase H-bridge circuit are sequentially turned on, the upper arm switch Q3 of the V-phase H-bridge circuit and the lower arm switch Q6 of the W-phase H-bridge circuit are sequentially turned on, and the upper arm switch Q5 of the W-phase H-bridge circuit and the lower arm switch Q2 of the U-phase H-bridge circuit are sequentially turned on, forming a rotating magnetic field to drive the motor to rotate in the forward direction;
[0067] Reversal phase: Switching to the upper arm switch Q1 of the U-phase H-bridge circuit and the lower arm switch Q6 of the W-phase H-bridge circuit, the upper arm switch Q5 of the W-phase H-bridge circuit and the lower arm switch Q4 of the V-phase H-bridge circuit, and the upper arm switch Q3 of the V-phase H-bridge circuit and the lower arm switch Q2 of the U-phase H-bridge circuit, the drive motor rotates in the reverse direction.
[0068] Working principle explanation: The motor drives the fan blades in a periodic forward and reverse rotation. When rotating in the reverse direction, the airflow impact and the inertial vibration of the blades work together to cause the attached dust to fall off the blade surface.
[0069] Specifically, the forward and reverse switching cycle can be set according to the degree of dust accumulation (e.g., reverse for 10 seconds every 30 minutes of operation). The motor shaft drives the fan blades to quickly change direction, and the sudden change in airflow direction and mechanical vibration cause the dust to be removed from the blade surface.
[0070] For ease of description, each phase of the H-bridge circuit is marked in the initial state, with 1 indicating that it is on and 0 indicating that it is off, in the order of U phase, V phase, and W phase. For example, the mark 110 indicates that the U phase H-bridge circuit and the V phase H-bridge circuit are on, and the W phase H-bridge circuit is off.
[0071] The initial state includes forward drive and reverse drive.
[0072] As shown in Table 1, this embodiment provides the drive signals for each timing sequence within one operating cycle when the markers 101, 100, 110, 010, 011, and 001 are considered as the initial state of forward rotation drive. Here, turning on the upper arm switch of the H-bridge circuit is denoted as +, turning on the lower arm switch of the H-bridge circuit is denoted as -, and neither the upper nor lower arm of this phase of the H-bridge circuit is turned on is denoted as X.
[0073] Table 1 Drive signals during one operating cycle of forward rotation drive.
[0074]
[0075] As shown in Table 2, this embodiment provides the driving signals for each timing sequence within one operating cycle when the markers 110, 100, 101, 001, 011, and 010 are considered as the initial state reverse drive. Here, turning on the upper arm switch of the H-bridge circuit is denoted as +, turning on the lower arm switch of the H-bridge circuit is denoted as -, and neither the upper nor lower arm of this phase of the H-bridge circuit is turned on is denoted as X.
[0076] Table 2 shows the drive signals for the reverse drive during one operating cycle.
[0077]
[0078] The three-phase H-bridge circuit provided in this embodiment works collaboratively through the complementary drive signals U, V, and W to form a continuous and balanced current path. This reduces energy loss caused by current discontinuity in single-phase drive, while improving the smoothness of motor torque output and reducing operating noise and vibration. It is suitable for dust removal and heat dissipation scenarios requiring frequent forward and reverse rotation. The modular three-phase H-bridge circuit design adapts to the needs of motors with different power ratings, offering strong scalability. The three-phase drive mode reduces energy loss, optimizes torque output smoothness, and improves overall energy efficiency. The drive unit enables smooth switching between forward and reverse rotation of the motor, avoiding the short-circuit risk caused by simultaneous conduction of the upper and lower bridge arms, thus improving system safety and response efficiency.
[0079] Example 2:
[0080] This embodiment provides a PCB board on which the motor drive circuit provided in Embodiment 1 is printed.
[0081] like Figure 2 As shown, the PCB board includes: a hollow area, a pad group, and a stator pin interface.
[0082] The hollow area is located in the middle of the PCB board to enhance heat dissipation and mechanical stability.
[0083] In this embodiment, the hollowed-out area has a rectangular cutout structure, which is used to enhance the airflow of heat dissipation and improve the bending strength of the PCB board.
[0084] The hollowed-out area in the middle of the PCB board can increase the heat dissipation area, optimize airflow distribution, and significantly improve heat dissipation efficiency. At the same time, the structural reinforcement reduces the risk of deformation caused by thermal expansion or vibration.
[0085] The pads are arranged in a ring around the periphery of the empty area to connect the motor drive circuit to the motor.
[0086] In this embodiment, the pad group includes COM pad, U-phase pad, V-phase pad, W-phase pad, and ground pad.
[0087] One end of the COM pad is connected to the U-phase CON point, V-phase CON point and W-phase CON point in the motor drive circuit provided in Example 1 via copper foil traces, and the other end is connected to the U-phase pad, V-phase pad and W-phase pad.
[0088] The U-phase pad, V-phase pad, and W-phase pad are respectively connected to the output pins of the U, V, and W-phase windings of the motor.
[0089] The grounding pad is used to connect the source and ground wire of each phase lower bridge arm switching transistor in the motor drive circuit provided in Example 1. Furthermore, the grounding pad is connected to the ground layer of the PCB board.
[0090] The stator pin interface is located on the surface of the PCB board and is connected to the grounding pad.
[0091] In this embodiment, the stator pin interface is located on the edge of the PCB board and connected to the grounding pad through a through hole, which is used to fix the motor stator and realize grounding.
[0092] The reasonable layout of the ring-shaped pad group (COM pad, U / V / W phase pad and ground pad) and stator pin interface simplifies the physical connection between the motor and the drive circuit, and reduces wiring complexity and installation errors.
[0093] This embodiment simplifies the physical connection between the motor and the drive circuit by rationally arranging the solder pads, thereby reducing wiring complexity and installation errors.
[0094] Example 3:
[0095] This embodiment provides a motor, which operates using the motor drive circuit provided in Embodiment 1.
[0096] The motor provided in this embodiment can drive the fan blades to rotate periodically in the opposite direction by reversing the operation. The vibration effect generated by the change in airflow direction causes the accumulated dust to fall off the blade surface, thus maintaining the long-term efficient heat dissipation of the fan.
[0097] Significant improvements have been made in terms of safety during forward / reverse switching, heat dissipation efficiency, dust removal effect, and structural reliability, making it particularly suitable for dust removal and cooling fan scenarios that require long-term stable operation.
[0098] As a further improvement, this embodiment can be applied to heat dissipation and dust removal in all electronic device systems on the market.
[0099] In the description of this utility model, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. In addition, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0100] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.
[0101] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A motor drive circuit, characterized in that, include: Three-phase H-bridge circuit unit and drive unit; The three-phase H-bridge circuit unit includes a U-phase H-bridge circuit, a V-phase H-bridge circuit and a W-phase H-bridge circuit. Each phase H-bridge circuit includes an upper bridge arm switch and a lower bridge arm switch. In the U-phase H-bridge circuit, the drain of the upper arm switch is connected to the positive terminal of the power supply, and the source is connected to the CON point of the U-phase. The drain of the lower arm switch is connected to the CON point of the U-phase, and the source is grounded. In the V-phase H-bridge circuit, the drain of the upper arm switch is connected to the positive terminal of the power supply, and the source is connected to the CON point of the V-phase. The drain of the lower arm switch is connected to the CON point of the V-phase, and the source is grounded. In the W-phase H-bridge circuit, the drain of the upper arm switch is connected to the positive terminal of the power supply, and the source is connected to the CON point of the W-phase. The drain of the lower arm switch is connected to the CON point of the W-phase, and the source is grounded. The driving unit includes 6 driving signal lines, which are respectively connected to the gates of the switching transistors of each phase H-bridge circuit, and are used to switch the conduction level of each phase and each bridge arm switching transistor according to the chip signal.
2. The motor drive circuit according to claim 1, characterized in that, The switching transistors in the three-phase H-bridge circuit unit are N-channel MOSFETs.
3. The motor drive circuit according to claim 1, characterized in that, In the three-phase H-bridge circuit unit, the drive signals of the upper bridge arm switch and the lower bridge switch of each phase H-bridge circuit are complementary logic signals, and there is a dead time between the drive signals of the upper bridge arm switch and the drive signals of the lower bridge switch.
4. The motor drive circuit according to claim 1, characterized in that, The three-phase H-bridge circuit unit also includes a current limiting circuit. One end of the current limiting circuit is connected to the drain of the lower bridge arm switching transistor of each phase H-bridge circuit, and the other end is grounded.
5. The motor drive circuit according to claim 1, characterized in that, The three-phase H-bridge circuit unit also includes multiple RC snubber circuits, which are connected in parallel between the drain and source of each switching transistor to absorb voltage spikes during the switching process.
6. A PCB board, characterized in that, The PCB board is printed with a motor drive circuit as described in any one of claims 1-5.
7. The PCB board according to claim 6, characterized in that, include: The hollow area is located in the middle of the PCB board to enhance heat dissipation and mechanical stability; The pads are arranged in a ring around the periphery of the empty area and are used to connect the motor drive circuit to the motor.
8. The PCB board according to claim 7, characterized in that, The pad group includes COM pad, U-phase pad, V-phase pad, W-phase pad, and ground pad; One end of the COM pad is connected to the U-phase CON point, V-phase CON point and W-phase CON point in the motor drive circuit, and the other end is connected to the U-phase pad, V-phase pad and W-phase pad. The U-phase pad, V-phase pad, and W-phase pad are respectively connected to the output pins of the U, V, and W phase windings of the motor. The grounding pad is used to connect the source of each phase lower bridge arm switch transistor in the motor drive circuit to the ground wire.
9. The PCB board according to claim 8, characterized in that, It also includes a stator pin interface, which is located on the surface of the PCB board and connected to the grounding pad.
10. An electric motor, characterized in that, The motor operates using the motor drive circuit described in any one of claims 1-5.