Vehicle brush direct current motor driving protection circuit, electronic equipment and vehicle

Abstract

The invention discloses a vehicle brush direct current motor driving protection circuit, electronic equipment and a vehicle. The vehicle brush direct current motor driving protection circuit comprises an NMOS transistor, a driving circuit and a protection circuit. The drain electrode of the NMOS transistor is connected with a motor power supply voltage, the source electrode of the NMOS transistor is connected with one end of a motor, the other end of the motor is connected with a power ground, and the NMOS transistor is used for driving the motor; the grid electrode of the NMOS transistor is respectively connected with a first driving signal and the driving circuit, one end of the driving circuit is connected with system ground, and the driving circuit is used for controlling the conducting state of the NMOS transistor; the protection circuit is respectively connected with the driving circuit and a second driving signal, one end of the protection circuit is connected with the system ground, and the protection circuit is used for preventing the NMOS transistor from being damaged and mistakenly conducted under the condition of ground wire drifting.

Description

Technical Field

[0001] The present invention belongs to the technical field of electronic circuits, and particularly relates to a brush DC motor drive protection circuit for vehicles, an electronic device, and a vehicle. Background Art

[0002] There are various motors in vehicles, and the driving of the motors is achieved through a drive circuit. In some systems using brushed DC motors, a single drive circuit is usually used. In addition, when ground drift occurs, it is easy to cause the motor to be accidentally turned on and the NMOS (N-Metal-Oxide-Semiconductor) to be damaged. Summary of the Invention

[0003] An object of the present invention is to provide a brush DC motor drive protection circuit for vehicles, an electronic device, and a vehicle, which can solve the technical problems of low reliability of the drive circuit in the prior art and the easy occurrence of accidental motor turn-on and NMOS damage when ground drift occurs.

[0004] According to a first aspect of the present invention, there is provided a brush DC motor drive protection circuit for vehicles, including an NMOS transistor, a drive circuit, and a protection circuit; The drain of the NMOS transistor is connected to the motor supply voltage, the source of the NMOS transistor is connected to one end of the motor, the other end of the motor is connected to the power ground, and the NMOS transistor is used to drive the motor; The gate of the NMOS transistor is respectively connected to a first drive signal and the drive circuit, one end of the drive circuit is connected to the system ground, and the drive circuit is used to control the on-state of the NMOS transistor; The protection circuit is respectively connected to the drive circuit and a second drive signal, one end of the protection circuit is connected to the system ground, and the protection circuit is used to avoid damage to the NMOS transistor and mis-conduction in the case of ground drift.

[0005] Optionally, the drive circuit includes a composite transistor, and the composite transistor includes a first transistor and a second transistor; The collector of the first transistor is connected to the gate of the NMOS transistor, the emitter of the first transistor is connected to the collector of the second transistor, the base of the first transistor is respectively connected to the first end of a third resistor and the first end of a fourth resistor, the second end of the third resistor is connected to the protection circuit, and the second end of the fourth resistor is connected to the emitter of the first transistor.

[0006] Optionally, the base of the second transistor is respectively connected to the emitter of the second transistor and the power ground, and the second transistor is used to prevent reverse connection.

[0007] Optionally, the drive circuit further includes a first capacitor, and two ends of the first capacitor are respectively connected to two ends of the fourth resistor.

[0008] Optionally, the drive circuit further includes a second capacitor, a first end of the second capacitor is connected to an emitter of the second transistor, and a second end of the second capacitor is connected to system ground.

[0009] Optionally, the first transistor is an NPN transistor, and the second transistor is a PNP transistor.

[0010] Optionally, the protection circuit includes a third transistor, a base of the third transistor is connected to the second drive signal, an emitter of the third transistor is connected to system ground, a collector of the third transistor is respectively connected to a first end of the first resistor, a first end of the second resistor, and a second end of the third resistor, a second end of the second resistor is connected to system ground, and a second end of the first resistor is connected to system power supply.

[0011] Optionally, the third transistor is an NPN transistor.

[0012] According to a second aspect of the present invention, there is provided an electronic device including a vehicle brushed DC motor drive protection circuit according to the first aspect of the present invention.

[0013] According to a third aspect of the present invention, there is provided a vehicle including an electronic device according to the second aspect of the present invention.

[0014] The beneficial effects of the present invention are as follows: The present invention realizes the logic with the protection circuit and the drive circuit to jointly drive the motor. The motor will only be turned on when both the first drive signal and the second drive signal are at high level, improving reliability. At the same time, when ground wire drift occurs, the drift voltage generated at the first drive signal terminal can be suppressed to the low level of the power ground, avoiding mis-conduction and preventing the NMOS from being damaged due to ground wire drift. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a schematic diagram of a vehicle brushed DC motor drive protection circuit in an embodiment of the present invention. DETAILED DESCRIPTION

[0016] Now, various exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that: Unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions and values set forth in these embodiments do not limit the scope of the present invention.

[0017] The following description of at least one exemplary embodiment is merely illustrative in nature and in no way serves as a limitation to the present invention or its application or use.

[0018] Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such technologies, methods, and devices should be regarded as part of the specification. In all the examples shown and discussed here, any specific values should be construed as merely exemplary, rather than as limitations. Thus, other examples of the exemplary embodiments may have different values.

[0019] It should be noted that like reference numerals and letters denote like items in the following figures, and thus, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0020] In the description of the present invention, features related to the terms "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more. In addition, "and / or" in the specification means at least one of the connected objects, and the character " / ", generally represents an "or" relationship between the associated objects before and after.

[0021] This embodiment introduces a brush DC motor drive protection circuit for a vehicle, including an NMOS transistor, a drive circuit, and a protection circuit.

[0022] The drain of the NMOS transistor is connected to the motor supply voltage VB_MOT, the source of the NMOS transistor is connected to one end of the motor, the other end of the motor is connected to the power ground, and the NMOS transistor is used to drive the motor.

[0023] The gate of the NMOS transistor is connected to the first drive signal and the drive circuit respectively. One end of the drive circuit is connected to the system ground, and the drive circuit is used to control the on-state of the NMOS transistor.

[0024] The protection circuit is connected to the drive circuit and the second drive signal respectively. One end of the protection circuit is connected to the system ground, and the protection circuit is used to prevent the NMOS transistor from being damaged and from being mis-conducted in the case of ground wire drift.

[0025] In the control units of on-vehicle chassis controllers such as products like ABS (Antilock Brake System) and ESC (Electronic Stability Control), there are usually multiple ground wire loops, such as digital ground, logic ground, power ground, etc. According to different hardware solutions, the handling methods of different ground wires are different. In the present invention, small-current ground wires such as logic ground and digital ground are connected together and collectively referred to as the system ground GND, and the ground wire of the load brush motor is independent of the system ground and is called the power ground GND_P.

[0026] The first driving signal is connected to the gate of the NMOS transistor and is used to provide a conducting voltage to the NMOS transistor. The driving circuit is also connected to the gate of the NMOS transistor, and the driving circuit can be used to pull down the gate voltage of the NMOS transistor, so that the NMOS transistor is turned off. By controlling the state of the driving circuit, the conduction or cutoff of the NMOS transistor can be controlled accordingly.

[0027] The second driving signal is connected to the protection circuit, and the state of the protection circuit can be controlled. Then, according to the state of the protection circuit, the state of the driving circuit can be controlled. The conduction or cutoff of the NMOS transistor is controlled by the protection circuit and the driving circuit together.

[0028] The first driving signal is connected to the ASIC or the high-side driver chip, and the second driving signal is connected to the IO interface of the MCU. The MCU, the ASIC, or the high-side driver chip all refer to the system ground as the reference ground.

[0029] As Figure 1 shown, the driving circuit includes a composite transistor, and the composite transistor includes a first transistor Q02A and a second transistor Q02B.

[0030] The collector of the first transistor Q02A is connected to the gate of the NMOS transistor DRV1, the emitter of the first transistor Q02A is connected to the collector of the second transistor Q02B, the base of the first transistor Q02A is respectively connected to the first end of the third resistor R03 and the first end of the fourth resistor R04, the second end of the third resistor R03 is connected to the protection circuit, and the second end of the fourth resistor R04 is connected to the emitter of the first transistor Q02A.

[0031] The base of the second transistor Q02B is respectively connected to the emitter of the second transistor Q02B and the power ground, and the second transistor is used to prevent reverse connection.

[0032] The driving circuit further includes a first capacitor C01, and both ends of the first capacitor C01 are respectively connected to both ends of the fourth resistor R04.

[0033] The driving circuit further includes a second capacitor C02, the first end of the second capacitor C02 is connected to the emitter of the second transistor Q02B, and the second end of the second capacitor C02 is connected to the system ground.

[0034] The first transistor is an NPN transistor, and the second transistor is a PNP transistor.

[0035] As Figure 1As shown, GND represents the system ground, and GND_P represents the power ground. When the first driving signal MOT_CTRL1 is at a high level, when the first transistor Q02A is turned on, the first driving signal MOT_CTRL1 is pulled down to a low level, causing the motor to fail to start. When the first transistor Q02A is turned off, it does not affect the level of the first driving signal MOT_CTRL1, and the first driving signal MOT_CTRL1 is at a high level, and the motor starts. When the first driving signal MOT_CTRL1 is at a low level, the motor is turned off. The third resistor R03 is a current-limiting resistor to prevent excessive base current of the transistor.

[0036] The second transistor Q02B is used for reverse connection prevention. Under normal use conditions, the collector voltage of the second transistor Q02B is greater than the emitter voltage, and the second transistor Q02B is turned on. In the case of reverse power supply connection, the negative voltage passes through the internal diode of the NMOS transistor, which is equivalent to the emitter voltage of the second transistor Q02B being greater than the collector voltage, and the second transistor Q02B is cut off to protect the internal circuit.

[0037] As Figure 1 As shown, the protection circuit includes a third transistor Q01. The base of the third transistor Q01 is connected to the second driving signal MOT_CTRL2. The emitter of the third transistor Q01 is connected to the system ground. The collector of the third transistor Q01 is respectively connected to the first end of the first resistor R01, the first end of the second resistor R02, and the second end of the third resistor R03. The second end of the second resistor R02 is connected to the system ground. The second end of the first resistor R01 is connected to the system power supply VCC. The third transistor is an NPN transistor.

[0038] The second driving signal MOT_CTRL2 is used to control the conduction state of the third transistor Q01. When the second driving signal MOT_CTRL2 is at a high level, the third transistor Q01 is turned on, causing the first transistor Q02A to be cut off, and it does not affect the level of the first driving signal MOT_CTRL1. In this case, if the first driving signal MOT_CTRL1 is also at a high level, then the motor starts.

[0039] If the second driving signal MOT_CTRL2 is at a low level when the first driving signal MOT_CTRL1 is at a high level, the third transistor Q01 is cut off. The system power supply VCC is divided by the first resistor R01 and the second resistor R02. The voltage generated after voltage division passes through the third resistor R03 and then turns on the first transistor Q02A, thereby pulling down the first driving signal MOT_CTRL1 to a low level.

[0040] The motor can only be started when both the first drive signal MOT_CTRL1 and the second drive signal MOT_CTRL2 are at high level. When either of them is at low level, the motor drive can be turned off, improving the system reliability.

[0041] The above analysis is based on the premise that the ground wire does not drift. If the ground wire drifts, the drift of the ground wire in the ON state does not affect the motor opening, but it is likely to cause overvoltage damage to the NMOS transistors V DS and V GS . In the OFF state, it is very easy to cause mis-conduction, resulting in damage to the NMOS transistors.

[0042] Since the MCU, ASIC, or high-side drive chip and VCC all refer to the system ground as the reference ground, when the ground wire drifts, i.e., GND > GND_P. Without a protection circuit, when the drift voltage is greater than the turn-on voltage of the NMOS transistor, that is, although the first drive signal MOT_CTRL1 is at low level relative to the system ground, it is at a high voltage that can turn on the NMOS transistor relative to the power ground GND_P, so mis-conduction is likely to occur. In addition, the drift voltage is not a stable voltage. When the voltage is unstable, it is also easy to make the NMOS transistor in the amplification region, causing damage to the NMOS transistor.

[0043] If there is a protection circuit, when a large ground wire offset occurs while the first drive signal MOT_CTR1 and the second drive signal MOT_CTR2 are at low level relative to the system ground, the third transistor Q01 is cut off, the first transistor Q02A is turned on, and the second transistor Q02B is turned on. Since the base and emitter of the second transistor Q02B are connected to the power ground GND_P, the drift voltage generated at the first drive signal MOT_CTR1 terminal will be suppressed to the level of the power ground due to the conduction of the first transistor Q02A and the second transistor Q02B, and no mis-conduction will occur, nor will NMOS damage caused by ground wire drift occur.

[0044] The present invention realizes the AND logic through the protection circuit and the drive circuit to jointly drive the motor. The motor will only be turned on when both the first drive signal and the second drive signal are at high level, improving the reliability. At the same time, when the ground wire drifts, the drift voltage generated at the first drive signal terminal can be suppressed to the low level of the power ground, avoiding mis-conduction and the situation of NMOS damage caused by ground wire drift.

[0045] This embodiment introduces an electronic device including a vehicle brushed DC motor drive protection circuit according to any embodiment of the present invention.

[0046] This embodiment introduces a vehicle including an electronic device according to any embodiment of the present invention.

[0047] Although some specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and not for limiting the scope of the present invention. Those skilled in the art should understand that the above embodiments can be modified without departing from the scope and spirit of the present invention.

[0048] Those of ordinary skill in the art can realize that the modules and algorithm steps described in connection with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods for each specific application to implement the described functions, but such implementation should not be considered to exceed the scope of the present invention.

[0049] Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working processes of the devices and equipment described above can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated herein.

[0050] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the modules is only a logical function division. In actual implementation, there may be other division methods. For example, multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the couplings or direct couplings or communication connections shown or discussed with each other can be through some interfaces. The indirect couplings or communication connections of the devices or modules can be in electrical, mechanical or other forms.

[0051] The modules described as separate components may or may not be physically separated. The components shown as modules may or may not be physical modules, that is, they can be located in one place or distributed to multiple network modules. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of the embodiments of the present invention.

[0052] In addition, the various functional modules in the embodiments of the present invention can be integrated into one processing module, or each module can exist physically alone, or two or more modules can be integrated into one module.

[0053] When the above-mentioned functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods of various embodiments of the present invention. The aforementioned storage medium includes: various media such as USB flash drives, mobile hard disks, ROM, RAM, magnetic disks, or optical discs that can store program codes.

[0054] The above description is only a preferred embodiment of the present application and an explanation of the applied technical principles. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by the specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the technical solutions formed by mutually replacing the above features with the (but not limited to) technical features with similar functions disclosed in the present application.

[0055] It should be understood that the magnitudes of the sequence numbers of the steps in the present invention's content and embodiments do not absolutely mean the sequence of execution. The execution sequence of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention. For the purposes of illustration and description, the foregoing description of the implementation of the present disclosure has been given. The foregoing description is not exhaustive and is not intended to limit the present disclosure to the exact form disclosed. According to the above teachings, various modifications and variations are possible, or various modifications and variations may be obtained from the practice of the present disclosure. These embodiments are selected and described to illustrate the principles of the present disclosure and its practical applications, so that those skilled in the art can utilize the present disclosure in various embodiments and various modifications suitable for the specific purposes contemplated.

Claims

1. A brush DC motor drive protection circuit for a vehicle, characterized in that, It includes an NMOS transistor, a drive circuit, and a protection circuit; The drain of the NMOS transistor is connected to the motor supply voltage, the source of the NMOS transistor is connected to one end of the motor, the other end of the motor is connected to the power ground, and the NMOS transistor is used to drive the motor; The gate of the NMOS transistor is connected to the first drive signal and the drive circuit respectively. One end of the drive circuit is connected to the system ground, and the drive circuit is used to control the on-state of the NMOS transistor; The protection circuit is connected to the drive circuit and the second drive signal respectively. One end of the protection circuit is connected to the system ground, and the protection circuit is used to prevent the NMOS transistor from being damaged and from being mis-conducted in the case of ground wire drift.

2. The brush DC motor drive protection circuit for a vehicle according to claim 1, wherein The drive circuit includes a composite transistor, and the composite transistor includes a first transistor and a second transistor; The collector of the first transistor is connected to the gate of the NMOS transistor, the emitter of the first transistor is connected to the collector of the second transistor, the base of the first transistor is connected to the first ends of a third resistor and a fourth resistor respectively, the second end of the third resistor is connected to the protection circuit, and the second end of the fourth resistor is connected to the emitter of the first transistor.

3. A brush DC motor drive protection circuit for a vehicle according to claim 2, characterized in that, The base of the second transistor is connected to the emitter of the second transistor and the power ground respectively, and the second transistor is used to prevent reverse connection.

4. A brush DC motor drive protection circuit for a vehicle according to claim 2, characterized in that, The drive circuit further includes a first capacitor, and both ends of the first capacitor are connected to both ends of the fourth resistor respectively.

5. A brush DC motor drive protection circuit for a vehicle according to claim 2, characterized in that, The drive circuit further includes a second capacitor, the first end of the second capacitor is connected to the emitter of the second transistor, and the second end of the second capacitor is connected to the system ground.

6. The brush DC motor drive protection circuit for a vehicle according to claim 2, characterized in that, The first transistor is an NPN transistor, and the second transistor is a PNP transistor.

7. A brush DC motor drive protection circuit for a vehicle according to claim 2, characterized in that, The protection circuit includes a third transistor, the base of the third transistor is connected to the second drive signal, the emitter of the third transistor is connected to the system ground, the collector of the third transistor is connected to the first ends of a first resistor, a second resistor, and the second end of the third resistor respectively, the second end of the second resistor is connected to the system ground, and the second end of the first resistor is connected to the system power supply.

8. A brush DC motor drive protection circuit for a vehicle according to claim 7, characterized in that, The third transistor is an NPN transistor.

9. An electronic device, characterized in that, A brush DC motor drive protection circuit for a vehicle according to any one of claims 1-8.

10. A vehicle, characterized in that, An electronic device according to claim 9.

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