Motor drive circuit and electronic device

Abstract

The utility model discloses a motor drive circuit and electronic equipment apply to motor drive field. In the circuit, the power supply end of H bridge motor drive circuit is linked with the power supply circuit, and the control end of H bridge motor drive circuit is linked with the control circuit, the control end of auxiliary bleed circuit is linked with the control circuit, and the first end of auxiliary bleed circuit is linked with the common end of upper bridge arm and lower bridge arm in H bridge motor drive circuit, and the second end of auxiliary bleed circuit is grounded through the sampling circuit in H bridge motor drive circuit. Based on above structure and corresponding connection relation can know, increased one auxiliary bleed circuit in H bridge motor drive circuit. In the process that H bridge motor drive circuit drives motor operation, and in the time period of dead time, through auxiliary bleed circuit, the voltage produced by body diode freewheeling in dead time can be bled, so as to eliminate the current distortion produced by voltage, and ensure that motor realizes zero voltage freewheeling in dead time.

Description

Technical Field

[0001] This utility model relates to the field of motor drive, and in particular to a motor drive circuit and electronic device. Background Technology

[0002] H-bridge motor drive circuits are commonly used circuits for motor drives, such as... Figure 1 As shown, the system comprises four transistors (e.g., MOSFETs, Metal-Oxide-Semiconductor Field-Effect Transistors) Q11, Q12, Q13, and Q14, each with its own body diode, and a resistor R11. The gates of Q11, Q12, Q13, and Q14 are all connected to the controller; the drain of Q11 is connected to the drain of Q12 and together to the power supply; the source of Q11 is connected to the drain of Q13 and together to the first terminal of the motor; the source of Q12 is connected to the drain of Q14 and together to the second terminal of the motor; the sources of Q13 and Q14 are connected and grounded. Its working principle is as follows: by controlling the on / off state of a pair of diagonally opposite transistors (Q11 and Q14 or Q12 and Q13), the polarity of the voltage across the motor is changed, thereby starting the motor.

[0003] In applications, to prevent the switching transistors (Q11 and Q13 or Q12 and Q14) on the same side of the H-bridge from simultaneously turning on due to overlapping control signals from the controller or residual signals from their own switches, thus causing a shoot-through short circuit and burning out the devices, a certain period of time (dead time) is actively delayed after one switching transistor turns off before turning on the other. However, during the dead time, all switching transistors are turned off, and the motor current freewheels through the body diode of the switching transistor. This can affect the motor due to the clamping voltage of the diode, causing the current to flatten, lag, or fluctuate near the zero-crossing point.

[0004] Currently, the average voltage error caused by the dead-time diode clamping is usually offset by adding or subtracting a compensation amount based on the direction of the motor phase current detected by software, according to the direction. However, the compensation accuracy of this method is heavily dependent on the current sampling accuracy and direction judgment, and it is easy to make mistakes near the current zero crossing point and in the direction judgment.

[0005] In view of the above-mentioned technologies, finding a way to achieve zero-voltage freewheeling in a motor during dead time is a problem that urgently needs to be solved by those skilled in the art. Utility Model Content

[0006] The purpose of this invention is to provide a motor drive circuit and electronic device. It can solve the problem in the prior art where adding or subtracting a compensation amount to the original PWM duty cycle to offset the average voltage error caused by the dead-time diode clamping, leading to dependence on current sampling accuracy and direction determination.

[0007] To solve the above-mentioned technical problems, this utility model provides a motor drive circuit, including: an H-bridge motor drive circuit and an auxiliary discharge circuit;

[0008] The power supply terminal of the H-bridge motor drive circuit is connected to the power supply circuit, and the control terminal of the H-bridge motor drive circuit is connected to the control circuit, which is used to drive the motor according to the control signal sent by the control circuit.

[0009] The control terminal of the auxiliary discharge circuit is connected to the control circuit. The first terminal of the auxiliary discharge circuit is connected to the common terminal of the upper and lower bridge arms in the H-bridge motor drive circuit. The second terminal of the auxiliary discharge circuit is grounded through the sampling circuit in the H-bridge motor drive circuit. It is used to discharge the voltage generated by the H-bridge motor drive circuit during the dead time.

[0010] Preferably, the auxiliary discharge circuit includes: a resonant inductor, a resonant capacitor, a diode, and an auxiliary switching transistor;

[0011] Among them, the first end of the resonant inductor is connected to the cathode of the diode, and together they serve as the first end of the auxiliary discharge circuit, which is connected to the common end of the upper and lower bridge arms.

[0012] The second terminal of the resonant inductor is connected to the first terminal of the resonant capacitor.

[0013] The second terminal of the resonant capacitor is connected to the first terminal of the auxiliary switching transistor and the anode of the diode;

[0014] The control terminal of the auxiliary switching transistor is connected to the control circuit as the control terminal of the auxiliary discharge circuit.

[0015] The second terminal of the auxiliary switch is grounded through the sampling circuit as the second terminal of the auxiliary discharge circuit.

[0016] Preferably, the auxiliary switching transistor is an auxiliary MOSFET with a body diode;

[0017] In this configuration, the drain of the auxiliary MOSFET serves as the first terminal of the auxiliary switching transistor, which is connected to the second terminal of the resonant capacitor and the anode of the diode.

[0018] The gate of the auxiliary MOSFET is connected to the control circuit as the control terminal of the auxiliary switching transistor.

[0019] The source of the auxiliary MOSFET is grounded through a sampling circuit as the second terminal of the auxiliary switching transistor.

[0020] Preferably, the H-bridge motor drive circuit further includes: a first switching transistor, a second switching transistor, a third switching transistor, and a fourth switching transistor;

[0021] Among them, the control terminals of the first switch, the second switch, the third switch, and the fourth switch are connected to the control circuit as the control terminals of the H-bridge motor drive circuit.

[0022] The first terminal of the first switching transistor is connected to the first terminal of the second switching transistor, and together they serve as the power supply terminal of the H-bridge motor drive circuit and are connected to the power supply circuit.

[0023] The second end of the first switch is connected to the first end of the third switch, and together they serve as the common end of the first upper bridge arm and the first lower bridge arm.

[0024] The second end of the second switch is connected to the first end of the fourth switch, and together they serve as the common end of the second upper bridge arm and the second lower bridge arm.

[0025] The second terminal of the third switch is connected to the second terminal of the fourth switch, the second terminal of the auxiliary discharge circuit, and the first terminal of the sampling circuit.

[0026] The common terminal of the first upper bridge arm and the first lower bridge arm is connected to the first terminal of the auxiliary discharge circuit, or the common terminal of the second upper bridge arm and the second lower bridge arm is connected to the first terminal of the auxiliary discharge circuit.

[0027] Preferably, the sampling circuit is a sampling resistor;

[0028] Among them, the first end of the sampling resistor is connected to the second end of the third switch, the second end of the fourth switch, and the second end of the auxiliary discharge circuit as the first end of the sampling circuit.

[0029] The second terminal of the sampling resistor is grounded.

[0030] Preferably, the first switching transistor is a first MOSFET with a body diode;

[0031] In this circuit, the drain of the first MOSFET serves as the first terminal of the first switch and is connected to the first terminal of the second switch and the power supply circuit.

[0032] The gate of the first MOS transistor is connected to the control circuit as the control terminal of the first switching transistor.

[0033] The source of the first MOSFET is connected as the second terminal of the first switch, and is connected to the first terminal of the third switch and the first terminal of the motor.

[0034] Preferably, the second switching transistor is a second MOSFET with a body diode;

[0035] In this circuit, the drain of the second MOSFET serves as the first terminal of the second switching transistor and is connected to the first terminal of the first switching transistor and the power supply circuit.

[0036] The gate of the second MOSFET is connected to the control circuit as the control terminal of the second switching transistor.

[0037] The source of the second MOSFET is connected to the second terminal of the second switch, the first terminal of the fourth switch, and the second terminal of the motor.

[0038] Preferably, the third switching transistor is a third MOSFET without a body diode;

[0039] Among them, the drain of the third MOSFET serves as the first terminal of the third switch and is connected to the second terminal of the first switch and the first terminal of the motor.

[0040] The gate of the third MOSFET is connected to the control circuit as the control terminal of the third switch.

[0041] The source of the third MOSFET is connected to the first terminal of the sampling circuit and the second terminal of the fourth MOSFET, serving as the second terminal of the third switch.

[0042] Preferably, the fourth switching transistor is a fourth MOSFET without a body diode;

[0043] Among them, the drain of the fourth MOSFET serves as the first terminal of the fourth switch and is connected to the second terminal of the second switch and the second terminal of the motor.

[0044] The gate of the fourth MOSFET is connected to the control circuit as the control terminal of the fourth switch.

[0045] The source of the fourth MOSFET is connected to the first terminal of the sampling circuit and the second terminal of the third MOSFET, serving as the second terminal of the fourth switch.

[0046] On the other hand, this application also provides an electronic device including the above-described motor drive circuit.

[0047] The motor drive circuit provided by this utility model, based on its specific structure and corresponding connections, incorporates an auxiliary discharge circuit within the H-bridge motor drive circuit. During the operation of the motor driven by the H-bridge motor drive circuit, and specifically within the dead time period, the auxiliary discharge circuit discharges the voltage generated by the freewheeling current of the body diode during the dead time, thereby eliminating current distortion caused by voltage and ensuring zero voltage freewheeling during the dead time. Attached Figure Description

[0048] To more clearly illustrate the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0049] Figure 1 This is a circuit diagram of an H-bridge motor drive circuit in the prior art;

[0050] Figure 2 This is a structural diagram of a motor drive circuit provided in an embodiment of this application;

[0051] Figure 3 This is a circuit diagram of a motor drive circuit provided in an embodiment of this application. Detailed Implementation

[0052] 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.

[0053] The core of this utility model is to provide a motor drive circuit and an electronic device.

[0054] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0055] Figure 2 A structural diagram of a motor drive circuit provided in an embodiment of this application is shown below. Figure 1 As shown, it includes: an H-bridge motor drive circuit 1 and an auxiliary discharge circuit 2. In addition, Figure 1 The motor drive circuit shown also includes: control circuit 3, motor M, sampling circuit 4, and power supply circuit 5.

[0056] The connection relationship of its motor drive circuit is as follows: the power supply terminal of H-bridge motor drive circuit 1 is connected to power supply circuit 5; the control terminal of H-bridge motor drive circuit 1 is connected to control circuit 3; the control terminal of auxiliary discharge circuit 2 is connected to control circuit 3; the first terminal of auxiliary discharge circuit 2 is connected to the common terminal of the upper and lower bridge arms in H-bridge motor drive circuit 1; the second terminal of auxiliary discharge circuit 2 is grounded through sampling circuit 5 in H-bridge motor drive circuit 1.

[0057] In a specific embodiment, the H-bridge motor drive circuit 1 typically consists of four switching transistors and a sampling circuit 5, mainly used to drive the motor. The two ends of the motor M are connected to the common terminals of the two upper bridge arms and the corresponding lower bridge arms in the H-bridge motor drive circuit 1. The connection method between the switching transistors and the motor M is as follows: Figure 1 .

[0058] In practical applications, to prevent the switching transistors on the same side of the motor drive circuit 1 from simultaneously conducting due to overlapping control signals from the control circuit or residual signals from their own switching, which could cause a shoot-through short circuit and burn out the devices, a certain period of time (dead time) is actively delayed after one switching transistor turns off before turning on the other. Ideally, the phase voltage of motor M should be strictly equal to the voltage Vdc determined by the duty cycle of the PWM. However, during the dead time, since all switching transistors are turned off, the current of motor M loses its active control path. Therefore, at this time, the freewheeling current of the motor depends entirely on the body diode inside the switching transistor. When the current is greater than 0, the current will freewheel through the body diode of the lower bridge arm, causing the voltage at the terminal of motor M to be clamped to -Vf (the forward voltage drop of the body diode), instead of the theoretical 0V. This reverse voltage will quickly "pull back" or "block" the current that should have crossed zero smoothly, causing the current to be flat, lagging, or jittery near the zero point, instead of a smooth S-shaped curve. When the current is less than 0, the current will freewheel through the body diode of the upper bridge arm, causing the voltage at the terminal of motor M to be clamped to Vdc+Vf, instead of the theoretical Vdc.

[0059] Therefore, in order to ensure that the motor M achieves zero voltage freewheeling during the dead time and that there is no current distortion in the circuit due to the voltage at the terminals of the motor M, an auxiliary discharge circuit 2 is added to the H-bridge motor drive circuit 1. The auxiliary discharge circuit 2 is specifically connected between the lower bridge arm of the H-bridge motor drive circuit 1 and ground, and is mainly used to discharge the voltage generated by the H-bridge motor drive circuit 1 during the dead time.

[0060] In this circuit, control circuit 3 primarily sends control signals to H-bridge motor drive circuit 1 and auxiliary discharge circuit 2. At time t0, control circuit 3 sends a control signal indicating shutdown to the two diagonally opposite switches in H-bridge motor drive circuit 1. Then, at time t0+Td, it sends a control signal indicating circuit startup to auxiliary discharge circuit 2, where Td is the dead time. Finally, at time t0+2Td, it sends a control signal indicating startup to the two diagonally opposite switches in H-bridge motor drive circuit 1 and simultaneously sends a control signal indicating circuit shutdown to auxiliary discharge circuit 2, thus completing one cycle. During the dead time, the voltage generated in H-bridge motor drive circuit 1 due to the freewheeling current in the body diodes of the switches is discharged by auxiliary discharge circuit 2.

[0061] In this application, the power supply circuit 5 mainly provides the VIN power supply voltage for the subsequent connected circuits, so it can be a power supply; the control circuit 3 provided in this application is mainly used to send control signals to the H-bridge motor drive circuit 1 and the auxiliary discharge circuit 2, so it can be a microcontroller (Micro Control Unit, MCU).

[0062] It should be noted that the dead time value is determined based on the different types of switching transistors in the H-bridge motor drive circuit 1. Therefore, the dead time can be shortened, the switching speed of the switching transistors can be accelerated, and the influence window of the dead time can be reduced by adjusting the type of switching transistor.

[0063] This utility model provides a motor drive circuit, comprising: an H-bridge motor drive circuit and an auxiliary discharge circuit; wherein, the power supply terminal of the H-bridge motor drive circuit is connected to the power supply circuit, and the control terminal of the H-bridge motor drive circuit is connected to the control circuit, used to drive the motor according to the control signal sent by the control circuit; the control terminal of the auxiliary discharge circuit is connected to the control circuit, the first terminal of the auxiliary discharge circuit is connected to the common terminal of the upper and lower bridge arms in the H-bridge motor drive circuit, and the second terminal of the auxiliary discharge circuit is grounded through the sampling circuit in the H-bridge motor drive circuit, used to discharge the voltage generated by the H-bridge motor drive circuit during the dead time. Based on the specific structure and corresponding connection relationships of the motor drive circuit, it can be seen that an auxiliary discharge circuit is added to the H-bridge motor drive circuit. During the operation of the motor driven by the H-bridge motor drive circuit, and within the dead time period, the auxiliary discharge circuit can discharge the voltage generated by the freewheeling current of the body diode during the dead time, thereby eliminating the current distortion caused by voltage and ensuring that the motor achieves zero voltage freewheeling during the dead time.

[0064] Based on the above embodiments, as a preferred embodiment, such as... Figure 3 As shown, its H-bridge motor drive circuit 1 further includes: a first switching transistor, a second switching transistor, a third switching transistor, and a fourth switching transistor. The first switching transistor is a first MOSFET Q1 with a body diode; the second switching transistor is a second MOSFET Q2 with a body diode; the third switching transistor is a third MOSFET Q3 without a body diode; and the fourth switching transistor is a fourth MOSFET Q4 without a body diode. In addition, the sampling circuit 4 in the H-bridge motor drive circuit 1 is a sampling resistor R. That is to say, the H-bridge motor drive circuit 1 is composed of the first MOSFET Q1, the second MOSFET Q2, the third MOSFET Q3, the fourth MOSFET Q4, and the sampling resistor R.

[0065] The connection relationship of its H-bridge motor drive circuit 1 is as follows: the control terminal of the first switch (gate of the first MOSFET Q1), the control terminal of the second switch (gate of the second MOSFET Q2), the control terminal of the third switch (gate of the third MOSFET Q3), and the control terminal of the fourth switch (gate of the fourth MOSFET Q4) are connected to the control circuit 3 as the control terminals of the H-bridge motor drive circuit 1; the first terminal of the first switch (drain of the first MOSFET Q1) and the first terminal of the second switch (drain of the second MOSFET Q2) are connected, and together they serve as the power supply terminal of the H-bridge motor drive circuit 1 and are connected to the power supply circuit 3; the second terminal of the first switch (gate of the first MOSFET Q4) is connected to the power supply circuit 3 as the power supply terminal of the H-bridge motor drive circuit 1; the second terminal of the first switch (gate of the first MOSFET Q1) is connected to the power supply circuit 3 as the power supply terminal of the H-bridge motor drive circuit 1; the second terminal of the first switch (gate of the first MOSFET Q2) is connected to the power supply circuit 3 as the power supply terminal of the H-bridge motor drive circuit 1. The source of Q1 is connected to the first terminal of the third switch (the drain of the third MOSFET Q3), and together they serve as the common terminal of the first upper and lower bridge arms of the H-bridge motor drive circuit 1; the second terminal of the second switch (the source of the second MOSFET Q2) is connected to the first terminal of the fourth switch (the drain of the fourth MOSFET Q4), and together they serve as the common terminal of the second upper and lower bridge arms of the H-bridge motor drive circuit 1; the second terminal of the third switch (the source of the third MOSFET Q3) is connected to the second terminal of the fourth switch (the source of the fourth MOSFET Q4), the second terminal of the auxiliary discharge circuit 2, and the first terminal of the sampling resistor R; the second terminal of the sampling resistor R is grounded.

[0066] The first MOSFET Q1 serves as the first upper bridge arm, and the second MOSFET Q2 serves as the second upper bridge arm; the third MOSFET Q3 serves as the first lower bridge arm, and the fourth MOSFET Q4 serves as the fourth lower bridge arm. Therefore, the common terminal of the first upper and lower bridge arms is the source of the first MOSFET Q1 and the drain of the third MOSFET Q3; the common terminal of the second upper and lower bridge arms is the source of the second MOSFET and the drain of the fourth MOSFET. In the connection relationship, since the auxiliary discharge circuit 2 only needs to be connected between the lower bridge arm and ground, its first terminal can be connected to the common terminal of the first upper and lower bridge arms, or to the common terminal of the second upper and lower bridge arms. It should be noted that... Figure 3 In the circuit shown, the first terminal of its auxiliary discharge circuit 2 can be connected to the common terminal of the first upper bridge arm and the first lower bridge arm.

[0067] The circuit operates as follows: when the control circuit 3 sends a signal indicating that the first MOSFET Q1 and the fourth MOSFET Q4 are turned on, and sends a signal indicating that the second MOSFET Q2 and the third MOSFET Q3 are turned off, the drive motor M rotates forward; when the control circuit 3 sends a signal indicating that the second MOSFET Q2 and the third MOSFET Q3 are turned on, and sends a signal indicating that the first MOSFET Q1 and the fourth MOSFET Q4 are turned off, the drive motor M rotates in reverse.

[0068] It should also be noted that the first and second switching transistors are MOSFETs with body diodes, specifically SiC MOSFETs; while the third and fourth switching transistors are MOSFETs without body diodes, specifically GaN MOSFETs. In other words, it is only necessary to ensure that the model numbers of the first and second switching transistors are different from those of the third and fourth switching transistors. This design approach results in extremely fast switching speeds, significantly reduces the impact window of the dead zone, and because the third and fourth switching transistors lack body diodes, their reverse conduction mechanisms differ, leading to lower and more linear Vf values, resulting in smaller voltage errors during the freewheeling phase.

[0069] like Figure 3 As shown, its auxiliary discharge circuit 2 includes: a resonant inductor L, a resonant capacitor C, a diode D, and an auxiliary switching transistor. The auxiliary switching transistor is an auxiliary MOSFET Q5 with a body diode.

[0070] The connection relationship of the auxiliary discharge circuit 2 is as follows: the first end of the resonant inductor L is connected to the cathode of the diode D, and together they serve as the first end of the auxiliary discharge circuit 2 and are connected to the common terminal of the upper and lower bridge arms; the second end of the resonant inductor L is connected to the first end of the resonant capacitor C; the second end of the resonant capacitor C is connected to the first end of the auxiliary switch (the drain of the auxiliary MOS transistor Q5) and the anode of the diode D; the control terminal of the auxiliary switch (the gate of the auxiliary MOS transistor Q5) serves as the control terminal of the auxiliary discharge circuit 2 and is connected to the control circuit 3; the second end of the auxiliary switch (the source of the auxiliary MOS transistor Q5) serves as the second end of the auxiliary discharge circuit 2 and is grounded through the sampling circuit 4 (sampling resistor R).

[0071] The operating principle of its auxiliary discharge circuit 2 is as follows: During the dead time period, the control circuit 3 sends a control signal indicating that the auxiliary MOSFET Q5 is turned on, so as to provide a freewheeling path for the motor M through the auxiliary discharge circuit 2. The freewheeling path passes through: resonant inductor L - resonant capacitor C - auxiliary MOSFET Q5 - sampling resistor R in sequence. Among them, the resonant inductor L and the resonant capacitor C form an oscillation circuit during the dead time period.

[0072] The conditions that need to be met in the design are: ;

[0073] in, This is the resonant frequency of the current auxiliary discharge circuit 2; Let L be the resonant inductance value; Let C be the resonant capacitance value; Pi; This is the driving frequency of the PWM.

[0074] It should be noted that the auxiliary discharge circuit 2 is only activated during the dead time period to achieve voltage discharge.

[0075] It should be noted that the embodiments provided in this application are only one possible implementation method, but are not limited to this only implementation method. Users can set their own implementation methods according to their needs.

[0076] In summary, by adding an auxiliary discharge circuit to the H-bridge motor drive circuit, during the dead time period of motor operation, the auxiliary discharge circuit can discharge the voltage generated by the freewheeling current of the body diode during the dead time, thereby eliminating current distortion caused by voltage and ensuring zero voltage freewheeling during the dead time. Furthermore, using different models of the first and second switching transistors compared to the third and fourth switching transistors can shorten the dead time, increase the switching frequency, and reduce losses.

[0077] On the other hand, this application also provides an electronic device that includes the motor drive circuit described above and has the same beneficial effects.

[0078] Since the embodiments provided in this application are the same as those provided in the above-described motor drive circuit, this application will not repeat them here.

[0079] The present invention provides a detailed description of a motor drive circuit and electronic device. The various embodiments are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the method section. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0080] It should also be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

Claims

1. A motor drive circuit, characterized in that, include: H-bridge motor drive circuit and auxiliary discharge circuit; The power supply terminal of the H-bridge motor drive circuit is connected to the power supply circuit, and the control terminal of the H-bridge motor drive circuit is connected to the control circuit, which is used to drive the motor according to the control signal sent by the control circuit. The control terminal of the auxiliary discharge circuit is connected to the control circuit. The first terminal of the auxiliary discharge circuit is connected to the common terminal of the upper and lower bridge arms in the H-bridge motor drive circuit. The second terminal of the auxiliary discharge circuit is grounded through the sampling circuit in the H-bridge motor drive circuit, and is used to discharge the voltage generated by the H-bridge motor drive circuit during the dead time.

2. The motor drive circuit according to claim 1, characterized in that, The auxiliary discharge circuit includes: a resonant inductor, a resonant capacitor, a diode, and an auxiliary switching transistor; The first end of the resonant inductor is connected to the cathode of the diode, and together they serve as the first end of the auxiliary discharge circuit, which is connected to the common end of the upper bridge arm and the lower bridge arm. The second end of the resonant inductor is connected to the first end of the resonant capacitor; The second terminal of the resonant capacitor is connected to the first terminal of the auxiliary switch and the anode of the diode; The control terminal of the auxiliary switching transistor is connected to the control circuit as the control terminal of the auxiliary discharge circuit. The second terminal of the auxiliary switch is grounded through the sampling circuit as the second terminal of the auxiliary discharge circuit.

3. The motor drive circuit according to claim 2, characterized in that, The auxiliary switching transistor is an auxiliary MOS transistor with a body diode; The drain of the auxiliary MOS transistor serves as the first terminal of the auxiliary switching transistor and is connected to the second terminal of the resonant capacitor and the anode of the diode. The gate of the auxiliary MOS transistor is connected to the control circuit as the control terminal of the auxiliary switch transistor. The source of the auxiliary MOS transistor is grounded through the sampling circuit as the second terminal of the auxiliary switch transistor.

4. The motor drive circuit according to any one of claims 1-3, characterized in that, The H-bridge motor drive circuit further includes: a first switching transistor, a second switching transistor, a third switching transistor, and a fourth switching transistor; The control terminals of the first switch, the second switch, the third switch, and the fourth switch are connected to the control circuit as the control terminals of the H-bridge motor drive circuit. The first terminal of the first switching transistor is connected to the first terminal of the second switching transistor, and together they serve as the power supply terminal of the H-bridge motor drive circuit and are connected to the power supply circuit. The second end of the first switch is connected to the first end of the third switch, and together they serve as the common end of the first upper bridge arm and the first lower bridge arm. The second end of the second switch is connected to the first end of the fourth switch, and together they serve as the common end of the second upper bridge arm and the second lower bridge arm. The second terminal of the third switch is connected to the second terminal of the fourth switch, the second terminal of the auxiliary discharge circuit, and the first terminal of the sampling circuit. Specifically, the common terminal of the first upper bridge arm and the first lower bridge arm is connected to the first terminal of the auxiliary discharge circuit, or the common terminal of the second upper bridge arm and the second lower bridge arm is connected to the first terminal of the auxiliary discharge circuit.

5. The motor drive circuit according to claim 4, characterized in that, The sampling circuit is a sampling resistor; Wherein, the first end of the sampling resistor serves as the first end of the sampling circuit and is connected to the second end of the third switch, the second end of the fourth switch, and the second end of the auxiliary discharge circuit; The second terminal of the sampling resistor is grounded.

6. The motor drive circuit according to claim 4, characterized in that, The first switching transistor is a first MOS transistor with a body diode; Wherein, the drain of the first MOS transistor serves as the first terminal of the first switching transistor and is connected to the first terminal of the second switching transistor and the power supply circuit; The gate of the first MOS transistor is connected to the control circuit as the control terminal of the first switching transistor. The source of the first MOS transistor is connected as the second terminal of the first switch transistor to the first terminal of the third switch transistor and the first terminal of the motor.

7. The motor drive circuit according to claim 4, characterized in that, The second switching transistor is a second MOSFET with a body diode; Wherein, the drain of the second MOS transistor serves as the first terminal of the second switching transistor and is connected to the first terminal of the first switching transistor and the power supply circuit; The gate of the second MOS transistor is connected to the control circuit as the control terminal of the second switching transistor. The source of the second MOS transistor serves as the second terminal of the second switch transistor and is connected to the first terminal of the fourth switch transistor and the second terminal of the motor.

8. The motor drive circuit according to claim 4, characterized in that, The third switching transistor is a third MOS transistor without a body diode; The drain of the third MOS transistor serves as the first terminal of the third switching transistor and is connected to the second terminal of the first switching transistor and the first terminal of the motor. The gate of the third MOS transistor is connected to the control circuit as the control terminal of the third switch transistor. The source of the third MOS transistor is connected as the second terminal of the third switch transistor to the first terminal of the sampling circuit and the second terminal of the fourth switch transistor.

9. The motor drive circuit according to claim 4, characterized in that, The fourth switching transistor is a fourth MOS transistor without a body diode; The drain of the fourth MOS transistor serves as the first terminal of the fourth switching transistor and is connected to the second terminal of the second switching transistor and the second terminal of the motor. The gate of the fourth MOS transistor is connected to the control circuit as the control terminal of the fourth switch transistor. The source of the fourth MOS transistor is connected as the second terminal of the fourth switch transistor to the first terminal of the sampling circuit and the second terminal of the third switch transistor.

10. An electronic device, characterized in that, Includes the motor drive circuit as described in any one of claims 1-9.

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