Driving circuit of switch tube, motor and range hood

Abstract

The invention discloses a driving circuit of a switching tube, a motor and a range hood, and belongs to the technical field of power electronics. The driving circuit of the switching tube comprises a driving chip used for generating a driving signal; the first end of the first impedance element is used for being electrically connected with a driving chip; the input end of the filtering unit is connected with the second end of the first impedance element, the output end of the filtering unit is used for being electrically connected with the driving end of the switching tube, and the filtering unit is configured to restrain alternating current components in the driving signal. According to the driving circuit of the switching tube, the first impedance element can be used as a driving resistor of the switching tube, and the filtering unit which is in a resistance state for an alternating current signal is connected in series between the driving resistor and the driving end of the switching tube, so that a high-frequency impedance path can be provided for high-frequency oscillation current excited in a high-speed switching process; high-frequency oscillation energy excited by a high-speed switch of a switching tube is attenuated, and the amplitude of the high-frequency oscillation energy is suppressed, so that electromagnetic interference generated by disturbance power is reduced.

Description

Technical Field

[0001] This application belongs to the field of power electronics technology, and in particular relates to a drive circuit for a switching transistor, a motor, and a smoke machine. Background Technology

[0002] Gallium nitride (GaN) power devices, due to their extremely high switching speed, are prone to generating high-frequency oscillations during operation, leading to interference power exceeding standard limits. Existing drive optimization techniques used for traditional MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors) have limited effectiveness in suppressing interference power in GaN power device applications, making it difficult to reduce the electromagnetic interference generated by interference power. Summary of the Invention

[0003] This application aims to at least solve one of the technical problems existing in the prior art. To this end, this application proposes a driving circuit for a switching transistor, a motor, and a smoke machine, which can provide a high-frequency impedance path for the high-frequency oscillating current excited during high-speed switching, attenuate the high-frequency oscillation energy excited by the high-speed switching of the switching transistor, and suppress its amplitude, thereby reducing electromagnetic interference generated by interference power.

[0004] In a first aspect, this application provides a driving circuit for a switching transistor, the driving circuit for the switching transistor comprising: The driver chip is used to generate drive signals; The first impedance element, the first end of the first impedance element is used for electrical connection with the driver chip; The filter unit has its input terminal connected to the second terminal of the first impedance element, and its output terminal electrically connected to the drive terminal of the switching transistor. The filter unit is configured to suppress AC components in the drive signal.

[0005] According to the driving circuit of the switching transistor in this application, the first impedance element can be used as the driving resistor of the switching transistor. A filter unit that is in a resistive state to AC signals is connected in series between the driving resistor and the driving terminal of the switching transistor. This can provide a high-frequency impedance path for the high-frequency oscillation current excited during high-speed switching, attenuate the high-frequency oscillation energy excited by the high-speed switching of the switching transistor, and suppress its amplitude, thereby reducing the electromagnetic interference generated by the interference power.

[0006] According to one embodiment of this application, the filtering unit includes: The first side of the ferrite bead is electrically connected to the second end of the first impedance element, and the second side of the ferrite bead is used to electrically connect to the driving end of the switching transistor.

[0007] According to one embodiment of this application, the switching transistor is a gallium nitride switching transistor, and the driving circuit of the switching transistor further includes: An electromagnetic energy storage device, wherein the first terminal of the electromagnetic energy storage device is electrically connected to the gate of a switching transistor, and the second terminal of the electromagnetic energy storage device is electrically connected to the source of the switching transistor.

[0008] According to one embodiment of this application, the electromagnetic energy storage device includes: The capacitor has its first terminal electrically connected to the gate of the switching transistor, and its second terminal electrically connected to the source of the switching transistor.

[0009] According to one embodiment of this application, the driving circuit for the switching transistor further includes: The second impedance element has its first end electrically connected to the driver chip and its second end electrically connected to the first end of the first impedance element. The resistance of the second impedance element is greater than that of the first impedance element.

[0010] According to one embodiment of this application, the driving circuit for the switching transistor further includes: The load circuit has its first end electrically connected to the first end of the driver chip and the first end of the first impedance element, and its second end electrically connected to the second end of the first impedance element. The load circuit is configured to consume the electrical energy of the second end of the first impedance element when the switch tube switches from the on state to the off state.

[0011] According to one embodiment of this application, the load circuit includes: The third impedance element has its first end electrically connected to the second end of the first impedance element. The unidirectional conducting device has its input terminal electrically connected to the second terminal of the third impedance element, and its output terminal electrically connected to both the driver chip and the first terminal of the first impedance element.

[0012] According to one embodiment of this application, the driving circuit for the switching transistor further includes: The fourth impedance element has its first end electrically connected to the gate of the switching transistor, and its second end electrically connected to the source of the switching transistor.

[0013] Secondly, this application provides an electric motor, which includes a gallium nitride power switch and a driving circuit for the aforementioned switch, wherein the driving circuit for the switch is electrically connected to the gate of the gallium nitride power switch.

[0014] According to the driving circuit of the switching transistor in this application, the first impedance element can be used as the driving resistor of the switching transistor. A filter unit that is in a resistive state to AC signals is connected in series between the driving resistor and the driving terminal of the switching transistor. This can provide a high-frequency impedance path for the high-frequency oscillation current excited during high-speed switching, attenuate the high-frequency oscillation energy excited by the high-speed switching of the switching transistor, and suppress its amplitude, thereby reducing the electromagnetic interference generated by the interference power.

[0015] Thirdly, this application provides a range hood, which includes the aforementioned motor.

[0016] According to the flue gas hood with a switching transistor of this application, the first impedance element can be used as the driving resistor of the switching transistor. A filter unit that is in a resistive state to AC signals is connected in series between the driving resistor and the driving terminal of the switching transistor. This can provide a high-frequency impedance path for the high-frequency oscillating current excited during high-speed switching, attenuate the high-frequency oscillation energy excited by the high-speed switching of the switching transistor, and suppress its amplitude, thereby reducing the electromagnetic interference generated by the interference power.

[0017] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0018] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a structural block diagram of the driving circuit for the switching transistor provided in an embodiment of this application; Figure 2 This is a circuit diagram of the driving circuit for the switching transistor provided in an embodiment of this application; Figure 3 This is one of the simulation results of the driving circuit of the switching transistor provided in the embodiments of this application; Figure 4 This is the second simulation result diagram of the driving circuit of the switching transistor provided in the embodiment of this application.

[0019] Figure label: The components include: driver chip 10, driver circuit for switch transistor 20, load circuit 30, filter unit 40, switch transistor Q, ferrite bead P, first to fourth impedance components R1~R4, capacitor C, and unidirectional conduction device D. Detailed Implementation

[0020] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0021] In the following description, a "circuit" refers to a conductive loop consisting of at least one element or sub-circuit connected by an electrical or electromagnetic link. When an element or circuit is said to be "coupled to" or "connected to" another element, or when an element / circuit is said to be "coupled at" or "connected at" two nodes, it can be directly coupled to or connected to the other element, or there may be intermediate elements. The connection between elements can be physical, logical, or a combination thereof. Conversely, when an element is said to be "directly coupled to" or "directly connected to" another element, it means that there are no intermediate elements between them.

[0022] In the description, the terms "first," "second," etc., are used to distinguish similar objects, not to describe a specific order or sequence. It should be understood that such numerical descriptors can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class, not limited in number; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0023] Furthermore, the use of terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicates that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0024] Gallium nitride (GaN) power devices, due to their superior material properties, can achieve switching speeds far exceeding those of traditional silicon-based MOSFETs in power electronics applications. However, this extremely high switching speed results in extremely high rates of voltage and current change during switching transients, easily triggering high-frequency oscillations caused by circuit parasitic parameters. These high-frequency oscillations not only interfere with the normal operation of the device itself but also cause a significant increase in system interference power, exceeding the limits specified by electromagnetic compatibility (EMC) standards, thus impacting equipment reliability and compliance.

[0025] Taking a range hood system as an example, if gallium nitride power devices are used in the motor drive section, the electromagnetic interference caused by high-frequency oscillations will be conducted or radiated along the motor cable, causing various hazards. For example, the electromagnetic interference caused by high-frequency oscillations may interfere with the normal operation of the microcontroller and sensors inside the range hood, causing fluctuations in motor speed, control failure, or abnormal display. In addition, strong interference signals may couple to the range hood's touch buttons or communication lines, leading to false triggering or communication interruption, seriously affecting the user experience.

[0026] In related technologies, the drive optimization method for traditional MOSFETs often involves increasing the gate drive resistance to slow down the switching edge and suppress oscillation. However, this method has limited effectiveness in gallium nitride (GaN) power devices because GaN power devices themselves have high switching speeds and low gate charge. Increasing the resistance will significantly increase switching losses and reduce system efficiency, making it difficult to realize the high-frequency and high-efficiency advantages that GaN power devices should possess.

[0027] To address the aforementioned issues, this application proposes a drive circuit for a switching transistor, a motor, and a smoke hood. By introducing a high-frequency impedance path in the drive circuit or power circuit, a high-frequency impedance path is provided for the high-frequency oscillation current excited during high-speed switching, thereby attenuating the high-frequency oscillation energy excited by the high-speed switching of the switching transistor and suppressing its amplitude, thus reducing electromagnetic interference generated by disturbance power.

[0028] Figure 1 A structural block diagram of the driving circuit 20 for the switch Q provided in an embodiment of this application is shown. (Refer to...) Figure 1 One embodiment of this application provides a driving circuit 20 for a switching transistor Q. The driving circuit 20 for the switching transistor Q includes a driving chip 10, a first impedance element R1, and a filtering unit 40. The driving chip 10 is used to generate a driving signal; the first terminal of the first impedance element R1 is used to be electrically connected to the driving chip 10; the input terminal of the filtering unit 40 is connected to the second terminal of the first impedance element R1, and the output terminal of the filtering unit 40 is used to be electrically connected to the driving terminal of the switching transistor Q. The filtering unit 40 is configured to suppress AC components in the driving signal.

[0029] A switching transistor Q is a semiconductor device capable of controlling current switching. The specific type of switching transistor Q can be selected according to the actual application scenario and is not limited here. For example, the switching transistor Q can be a gallium nitride (GaN) switching transistor, a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), an IGBT (Insulated-Gate Bipolar Transistor), or a bipolar transistor, etc. This application uses a gallium nitride (GaN) switching transistor Q as an example for illustration.

[0030] The driver chip 10 refers to the control unit that controls the power switch Q to turn on and off. The driver chip 10 is mainly used to receive low-power control signals from the front-end controller (such as an MCU or digital signal processor), and convert and amplify them into a drive signal with sufficient voltage and current driving capability to ensure that the switch Q can switch between the on and off states.

[0031] The first impedance element R1 is electrically connected between the output pin of the driver chip 10 and the driving terminal of the switch Q. The first impedance element R1 is usually mainly used to limit the peak value of the driving current, thereby controlling the switching speed of the switch Q and preventing damage to the driver chip 10 or the switch Q itself due to excessive instantaneous current.

[0032] The specific structure of the first impedance element R1 can be selected according to the actual application scenario, and is not limited here. For example, the first impedance element R1 can be a resistor.

[0033] The first end of the filter unit 40 is connected to the second end of the first impedance element R1, and the second end of the filter unit 40 is used to electrically connect to the drive terminal (i.e., gate) of the switching transistor Q. The filter unit 40 exhibits a resistive state to AC signals, that is, it presents extremely low impedance to the DC and low-frequency fundamental components of the drive signal, allowing the drive signal to pass through with almost no loss; however, for high-frequency oscillations excited by high-speed switching operations, the filter unit 40 will exhibit very high impedance. The oscillation energy is effectively absorbed by the filter unit 40 and converted into heat energy for dissipation, thus attenuating at the source of the oscillation and preventing it from radiating outward.

[0034] By introducing a filter unit 40 with frequency selectivity, the drive circuit 20 of the switch Q provided in this application embodiment can accurately filter out high-frequency oscillation components in the drive loop without affecting the normal switching control signal, thereby reducing electromagnetic interference generated by disturbance power.

[0035] According to the driving circuit 20 of the switching transistor Q in this application, the first impedance element R1 can be used as the driving resistor of the switching transistor Q. A filter unit 40 that is in a resistive state to AC signals is connected in series between the driving resistor and the driving terminal of the switching transistor Q. This can provide a high-frequency impedance path for the high-frequency oscillation current excited during the high-speed switching process, attenuate the high-frequency oscillation energy excited by the high-speed switching of the switching transistor Q, and suppress its amplitude, thereby reducing the electromagnetic interference generated by the interference power.

[0036] Figure 2 A structural block diagram of the driving circuit 20 for the switch Q provided in an embodiment of this application is shown. (Refer to...) Figure 2In some embodiments, the filter unit 40 includes a magnetic bead P, the first side of which is electrically connected to the second end of the first impedance element R1, and the second side of which is electrically connected to the drive end of the switching transistor Q.

[0037] A ferrite bead (P) is a passive component made of high-frequency ferrite material, essentially a lossy inductor. At low frequencies, the ferrite bead exhibits very low inductive reactance and resistance, allowing useful signals to pass through with almost no loss. This low-frequency range typically includes the fundamental frequency of the driving signal; however, as the frequency rises to the material's characteristic frequency, its resistive component increases sharply and becomes the dominant impedance, acting as a high-resistance resistor for high-frequency AC signals. This high-frequency impedance effectively attenuates the voltage amplitude of noise components along the signal path.

[0038] It should be noted that the specific type of ferrite bead P can be selected based on the actual application scenario, and is not limited here. The frequency range corresponding to the peak impedance of the selected ferrite bead P should cover the core frequency band of high-frequency oscillations and electromagnetic interference noise excited by the extremely fast switching speed of the gallium nitride switch.

[0039] During the normal switching process of the switching transistor Q, the driver chip 10 provides charging current to the gate through the drive resistor and the ferrite bead P. For the fundamental component of this switching action, the ferrite bead P exhibits low impedance and does not affect the switching speed. However, when the instantaneous switching action excites ultra-high frequency damped oscillations between the parasitic inductance of the drive circuit and the gate capacitance C, this high-frequency current flows through the ferrite bead P. The ferrite bead P absorbs its high-frequency energy and converts it into heat energy for dissipation, which can attenuate the oscillation amplitude and thus reduce the electromagnetic interference generated by the disturbance power.

[0040] In some embodiments, the switch Q is a gallium nitride switch, and the driving circuit 20 of the switch Q further includes an electromagnetic energy storage device. The first end of the electromagnetic energy storage device is electrically connected to the gate of the switch Q, and the second end of the electromagnetic energy storage device is electrically connected to the source of the switch Q.

[0041] The specific structure of the electromagnetic energy storage device can be selected according to the actual application scenario, and is not limited here. It can be a buffer circuit consisting of a resistor and a capacitor C connected in series, or it can be a single capacitor C structure.

[0042] The electromagnetic energy storage device is electrically connected between the gate and source of the gallium nitride switch, mainly to increase the total equivalent capacitance C between the gate and source.

[0043] Gallium nitride (GaN) switches typically have a small input capacitance C, which is one reason they can achieve extremely high switching speeds. However, this also makes them highly sensitive to high-frequency noise in the drive circuit, potentially affecting their stability and efficiency. By connecting an external electromagnetic energy storage device in parallel, the total equivalent capacitance C between the gate and source is increased, creating a lower impedance discharge path for high-frequency noise.

[0044] During high-speed switching in the power circuit, rapidly changing voltages couple through the Miller capacitance C between the gate and drain of the gallium nitride switch and the parasitic capacitance C of the printed circuit board, generating significant common-mode current. Without electromagnetic energy storage devices, the path of this current is complex and difficult to control.

[0045] After connecting the electromagnetic energy storage device in parallel, the equivalent capacitance C between the gate and source of the gallium nitride switch increases, providing a lower impedance discharge path for the high-frequency common-mode current. This allows most of the high-frequency noise current to flow to the grounding node through the electromagnetic energy storage device, instead of being forced to flow to the ground through the parasitic capacitance C, thus cutting off the path for the common-mode interference to be conducted outward.

[0046] In some embodiments, the electromagnetic energy storage device includes a capacitor C, with a first terminal of the capacitor C electrically connected to the gate of a switching transistor Q, and a second terminal of the capacitor C electrically connected to the source of the switching transistor Q.

[0047] Gallium nitride (GaN) switches have a relatively small inherent input capacitance C, making them quite sensitive to noise. The impedance of capacitor C decreases as the frequency increases. Directly connecting capacitor C in parallel between the gate and source of the switch Q provides a low-impedance discharge path for high-frequency noise in the drive circuit.

[0048] The specific capacitance value of capacitor C can be determined based on the switching frequency of the gallium nitride (GaN) switch, the inherent parasitic capacitance C of the GaN switch, and the noise frequency band to be suppressed; no specific limit is imposed here. For example, the capacitance value of capacitor C can be 1nF to 10nF.

[0049] Using a single capacitor C in parallel to increase the total equivalent capacitance C between the gate and source of the gallium nitride switch not only effectively increases the total equivalent capacitance C between the gate and source, but also has the advantage of low cost. Furthermore, a properly selected capacitor C has little impact on the normal switching drive signal, and can suppress high-frequency noise without sacrificing switching speed or introducing additional losses.

[0050] In some embodiments, the driving circuit 20 of the switching transistor Q further includes a second impedance element R2, the first end of the second impedance element R2 is electrically connected to the driving chip 10, the second end of the second impedance element R2 is electrically connected to the first end of the first impedance element R1, and the resistance of the second impedance element R2 is greater than the resistance of the first impedance element R1.

[0051] The second impedance element R2 is connected in series with the first impedance element R1. The total resistance after series connection is greater than the resistance of the first impedance element R1. That is, the second impedance element R2 in series is equivalent to increasing the value of the drive resistance. The turn-on and turn-off speed of the switch Q is inversely proportional to the value of the drive resistance. Therefore, increasing the total drive resistance can slow down the charging and discharging speed of the gate capacitance C of the switch Q, thereby effectively increasing the edge time of the switching waveform. A gentler switching edge means that the switching waveform contains fewer high-frequency harmonic components, which can suppress mid-frequency harmonic energy.

[0052] The resistance of the second impedance element R2 is greater than that of the first impedance element R1, which makes the total resistance after series connection greater than twice that of the first impedance element R1. This can significantly increase the edge time of the switching waveform and significantly suppress harmonic energy in the mid-frequency band.

[0053] It should be noted that the increase in driving resistance can be achieved not only by connecting the second impedance element R2 in series, but also by directly increasing the resistance value of the first impedance element R1. For example, the resistance value of the first impedance element R1 can be increased from 39Ω to 100Ω, thereby extending the switching edge time from 2ns to 4ns-6ns, reducing harmonic energy in the mid-frequency band, and improving the electromagnetic compatibility of the system.

[0054] The specific structure of the second impedance element R2 can be selected according to the actual application scenario, and is not limited here. For example, the second impedance element R2 can also be a resistor.

[0055] The driving resistance is increased by using a second impedance element R2 in series, which is simple in cost and easy to implement.

[0056] Figure 3 The curves showing the power interference versus frequency under a conventional switching transistor drive circuit are presented. Figure 4 The curve of power disturbance versus frequency under the drive circuit 20 of the switch transistor Q provided in the embodiment of this application is shown. Figure 3 Curve (1) shows the peak power interference as a function of frequency under the driving circuit of a traditional switching transistor, and curve (2) shows the average power interference as a function of frequency under the driving circuit of a traditional switching transistor. Figure 3 It can be seen that at a frequency of around 71MHz, the peak power disturbance of the conventional switching transistor Q driving circuit 20 is about 46.6dBμW, and the average power disturbance is about 35dBμW. Figure 4 Curve (3) is the curve showing the peak value of the power interference as a function of frequency under the driving circuit 20 of the switching transistor Q provided in this embodiment, and curve (4) is the curve showing the average value of the power interference as a function of frequency under the driving circuit 20 of the switching transistor Q provided in this embodiment. Figure 4As can be seen, at a frequency of around 71MHz, the peak power interference of the driving circuit 20 for the switch Q provided in this embodiment is approximately 41.12dBμW, and the average power interference is approximately 30dBμW. That is, by using the driving circuit 20 of this application to drive the switch Q, electromagnetic interference generated by the interference power can be reduced.

[0057] In some embodiments, the driving circuit 20 of the switching transistor Q further includes a load circuit. The first end of the load circuit is electrically connected to the driving chip 10 and the first end of the first impedance element R1, respectively. The second end of the load circuit is electrically connected to the second end of the first impedance element R1. The load circuit is configured to consume the electrical energy of the second end of the first impedance element R1 when the switching transistor Q switches from the on state to the off state.

[0058] When the driver chip 10 outputs a turn-off signal, causing the switching transistor Q to turn off rapidly, a very high negative voltage spike will be induced on its source inductor. This spike will be directly superimposed on the second terminal of the first impedance element R1 through circuit coupling, causing the potential at this point to momentarily drop far below the ground potential of the driver chip 10. This negative voltage spike, or the high-frequency oscillation caused by it, will be directly transmitted in the reverse direction to the output pin of the driver chip 10 through the first impedance element R1, causing damage to the internal structure of the chip.

[0059] The load circuit is connected in parallel across the two ends of the first impedance element R1. When a negative voltage or high-frequency oscillation occurs at the second end of the first impedance element R1 due to the turn-off action, the load circuit will immediately provide a current path to consume the electrical energy generated by the turn-off action.

[0060] The specific structure of the load circuit can be selected according to the actual application scenario, and is not limited here. For example, the load circuit may include a resistor, which can convert the energy of the negative voltage spike or the high-frequency oscillation caused by the rapid turn-off of the switching transistor Q into heat energy for dissipation.

[0061] The load circuit provides reverse voltage protection for the driver chip 10 by actively dissipating the energy of the negative voltage spike or the high-frequency oscillation caused by the switching transistor Q during the turn-off process, thereby improving the reliability of the entire driver circuit 20.

[0062] In some embodiments, the load circuit includes a third impedance element R3 and a unidirectional conducting device D. The first end of the third impedance element R3 is electrically connected to the second end of the first impedance element R1; the input end of the unidirectional conducting device D is electrically connected to the second end of the third impedance element R3, and the output end of the unidirectional conducting device D is electrically connected to the driver chip 10 and the first end of the first impedance element R1, respectively.

[0063] The unidirectional conducting device D has unidirectional conductivity and acts as an automatic switch in the circuit. Specifically, during the turn-off process of the switch Q, when the voltage at the second terminal of the first impedance element R1 is lower than the output voltage of the driver chip 10 due to the negative spike at the source, the diode will enter forward bias and conduct, opening a path for the discharge current. When the switch Q is on or in a steady state, the driver chip 10 outputs a high level, whose voltage is higher than the voltage at the second terminal of the first impedance element R1. At this time, the unidirectional conducting device D is reverse-biased and cut off, which makes the load circuit equivalent to being in an open state. This avoids the drive current being shunted by this branch during normal conduction, thereby ensuring that all drive current is used to charge the gate capacitor C of the switch Q, without affecting its normal conduction speed.

[0064] The specific type of unidirectional conducting device D can be selected according to the actual application scenario, and is not limited here. For example, unidirectional conducting device D can be a diode, with the anode of the diode electrically connected to the second end of the third impedance element R3, and the cathode of the diode electrically connected to the first end of the driving chip 10 and the first impedance element R1, respectively.

[0065] The third impedance element R3 can be a current-limiting resistor. R3 is connected in series with the unidirectional conducting device D, and its main function is to convert the discharged electrical energy into heat energy for dissipation. The load circuit formed by the third impedance element R3 and the unidirectional conducting device D connected in series can respond to and discharge turn-off voltage spikes in real time, avoiding negative voltage or oscillating voltage impacts on the output stage of the driver chip 10, and reducing the risk of damage to the driver chip 10 due to electrical overstress. Furthermore, due to the unidirectional conductivity of the unidirectional conducting device D, this load circuit is essentially in an open state when the switching transistor Q is normally turned on, without shunting the drive current or adding additional gate capacitance C, thus ensuring that the high-speed switching performance of the switching transistor Q is fully utilized.

[0066] The protection of the driver chip 10 is achieved at a very low cost using only a combination of a diode and a resistor. The solution has a simple structure, does not increase manufacturing complexity, but can improve the reliability of the driver circuit 20.

[0067] In some embodiments, the driving circuit 20 of the switch Q further includes a fourth impedance element R4, the first end of the fourth impedance element R4 being electrically connected to the gate of the switch Q, and the second end of the second end of the fourth impedance element R4 being electrically connected to the source of the switch Q.

[0068] The fourth impedance element R4 is electrically connected between the gate and source of the switching transistor Q, which can be electrically connected to the ground node. The main purpose of the fourth impedance element R4 is to ensure that the drive terminal of the switching transistor Q is explicitly pulled low to ground potential when the drive signal is floating or undefined, thereby ensuring that the switching transistor Q is in a reliable off state. This prevents false turn-on caused by electrostatic interference or transient phenomena during circuit power-on, greatly enhancing the circuit's anti-interference capability and stability.

[0069] One embodiment of this application provides a motor, which includes a gallium nitride power switch Q and a driving circuit 20 for the aforementioned switch Q, wherein the driving circuit 20 for the switch Q is electrically connected to the gate of the gallium nitride power switch Q.

[0070] Gallium nitride (GaN) power switches, specifically the Q-series power converter, serve as the core of the motor's power conversion and can form one arm of the motor inverter. Q-series switches are responsible for carrying the load current required to drive the motor. Compared to traditional silicon-based power switches, GaN power switches exhibit lower switching losses and higher switching efficiency under high-frequency, high-power-density conditions. Their inherently high switching speed allows the motor to operate at higher power densities without requiring excessive heat dissipation design.

[0071] The aforementioned driving circuit 20 (including a driving chip, a first impedance element, a filtering unit, and optional ferrite beads, gate-source energy storage capacitors, etc.) is directly connected to the gate of the switching transistor Q. It is mainly used to convert the low-voltage PWM signal emitted by the microcontroller (MCU) into a gate signal that can quickly and reliably drive the GaN switching transistor Q.

[0072] In the embodiments of this application, the drive circuit 20 not only provides drive energy, but its filter unit 40 is also resistive to AC signals, that is, it presents extremely low impedance to the DC and low-frequency fundamental components of the drive signal, allowing the drive signal to pass through with almost no loss. However, for high-frequency oscillations excited by high-speed switching operations, the filter unit 40 presents very high impedance. The oscillation energy is effectively absorbed by the filter unit 40 and converted into heat energy for dissipation, thereby attenuating it at the source of oscillation and preventing it from radiating outwards. This filters out the high-frequency oscillation components in the drive loop without affecting the normal switching control signal, reducing electromagnetic interference generated by disturbance power.

[0073] The high-frequency switching capability of the gallium nitride power switch Q can significantly improve the switching frequency of the motor drive. The drive circuit 20 provides a high-frequency impedance path for the high-frequency oscillating current excited during high-speed switching, attenuating the high-frequency oscillation energy excited by the high-speed switching of the switch and suppressing its amplitude, thereby reducing electromagnetic interference caused by disturbance power. The structure and working principle of the drive circuit 20 of the switch Q can be referred to the aforementioned embodiment, and will not be repeated here.

[0074] According to the driving circuit 20 of the switching transistor Q in this application, the first impedance element R1 can be used as the driving resistor of the switching transistor Q. A filter unit 40 that is in a resistive state to AC signals is connected in series between the driving resistor and the driving terminal of the switching transistor Q. This can provide a high-frequency impedance path for the high-frequency oscillation current excited during the high-speed switching process, attenuate the high-frequency oscillation energy excited by the high-speed switching of the switching transistor Q, and suppress its amplitude, thereby reducing the electromagnetic interference generated by the interference power.

[0075] One embodiment of this application provides a range hood that includes the aforementioned motor.

[0076] The motor, as the power source of the range hood, primarily drives the fan blades to rotate, generating suction to draw cooking fumes and odors from the kitchen into the range hood and then exhaust them outdoors through the ventilation system. The motor's power, speed, and stability directly affect the range hood's suction power and airflow, thus impacting the effectiveness of fume extraction and the air quality of the cooking environment.

[0077] In the embodiments of this application, the motor employs a gallium nitride (GaN) power switch and the aforementioned drive circuit 20 for the switch Q, which can provide higher power density, lower switching losses, and higher efficiency. Specifically, since the GaN power switch exhibits lower switching losses and higher switching efficiency under high frequency and high power density conditions, the GaN motor has lower power consumption and higher efficiency. During normal operation, the range hood can minimize energy waste. Furthermore, the high-frequency characteristics of the GaN power switch enable the motor it drives to respond quickly and maintain stable suction and exhaust capabilities. When the sensor detects a sudden increase in oil fumes, the motor can achieve instantaneous acceleration from low to high speed under the precise control of the drive circuit 20, thereby improving the oil fume extraction effect.

[0078] In addition, because gallium nitride power switches have lower switching losses and higher switching speeds, they can effectively reduce mechanical vibration and electromagnetic interference generated during fan operation. Smoke hoods using gallium nitride motors can reduce noise generation during operation.

[0079] Understandably, the motor employing gallium nitride (GaN) power switching transistors and the aforementioned drive circuit 20 for the switching transistor Q not only improves the suction power and efficiency of the range hood but also allows for a more compact design. Due to the high efficiency of GaN motors, the range hood can be made smaller while maintaining the same or stronger suction power. Furthermore, the high power density design of the motor enables the range hood to provide stronger power output without increasing its size, meeting the needs of different kitchen spaces.

[0080] According to the smoke machine of this application, the first impedance element R1 in the drive circuit 20 of the switch transistor Q can be used as the drive resistor of the switch transistor Q. A filter unit 40 that is in a resistive state to AC signals is connected in series between the drive resistor and the drive terminal of the switch transistor Q. This can provide a high-frequency impedance path for the high-frequency oscillation current excited during the high-speed switching process, attenuate the high-frequency oscillation energy excited by the high-speed switching of the switch transistor Q, and suppress its amplitude, thereby reducing the electromagnetic interference generated by the interference power.

[0081] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A driving circuit for a switching transistor, characterized in that, include: The driver chip is used to generate drive signals; A first impedance element, wherein a first end of the first impedance element is used to be electrically connected to the output terminal of the driver chip; A filtering unit, wherein the input terminal of the filtering unit is connected to the second terminal of the first impedance element, and the output terminal of the filtering unit is used to be electrically connected to the driving terminal of the switching transistor, and the filtering unit is configured to suppress the AC component in the driving signal.

2. The driving circuit for the switching transistor according to claim 1, characterized in that, The filtering unit includes: A magnetic bead, wherein a first side of the magnetic bead is electrically connected to a second end of the first impedance element, and the second side of the magnetic bead is used to be electrically connected to the driving end of the switching transistor.

3. The driving circuit for the switching transistor according to claim 1, characterized in that, The switching transistor is a gallium nitride switching transistor, and the driving circuit of the switching transistor further includes: An electromagnetic energy storage device, wherein a first terminal of the electromagnetic energy storage device is electrically connected to the gate of the switching transistor, and a second terminal of the electromagnetic energy storage device is electrically connected to the source of the switching transistor.

4. The driving circuit for the switching transistor according to claim 3, characterized in that, The electromagnetic energy storage device includes: A capacitor, wherein the first end of the capacitor is electrically connected to the gate of the switching transistor, and the second end of the capacitor is electrically connected to the source of the switching transistor.

5. The driving circuit for the switching transistor according to claim 1, characterized in that, The driving circuit for the switching transistor also includes: The second impedance element has a first end electrically connected to the driver chip and a second end electrically connected to the first end of the first impedance element. The resistance of the second impedance element is greater than the resistance of the first impedance element.

6. The driving circuit for the switching transistor according to any one of claims 1-5, characterized in that, The driving circuit for the switching transistor also includes: The load circuit has a first end electrically connected to the driver chip and the first end of the first impedance element, and a second end electrically connected to the second end of the first impedance element. The load circuit is configured to consume the electrical energy of the second end of the first impedance element when the switch tube switches from the on state to the off state.

7. The driving circuit for the switching transistor according to claim 6, characterized in that, The load circuit includes: A third impedance element, wherein the first end of the third impedance element is electrically connected to the second end of the first impedance element; A unidirectional conducting device, wherein the input terminal of the unidirectional conducting device is electrically connected to the second terminal of the third impedance element, and the output terminal of the unidirectional conducting device is electrically connected to the driving chip and the first terminal of the first impedance element, respectively.

8. The driving circuit for the switching transistor according to any one of claims 1-5, characterized in that, The driving circuit for the switching transistor also includes: A fourth impedance element, wherein the first end of the fourth impedance element is electrically connected to the gate of the switching transistor, and the second end of the second end of the fourth impedance element is electrically connected to the source of the switching transistor.

9. An electric motor, characterized in that, The motor includes a gallium nitride power switch and a drive circuit for the switch according to any one of claims 1-8, wherein the drive circuit for the switch is electrically connected to the gate of the gallium nitride power switch.

10. A range hood, characterized in that, The range hood includes the motor according to claim 9.

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