A vehicle brushed DC motor drive protection circuit, electronic equipment and vehicle

Abstract

The present invention discloses a vehicle brushed DC motor drive protection circuit, electronic device, and vehicle. The vehicle brushed DC motor drive protection circuit 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, and the other end of the motor is connected to a power ground. 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 a system ground. The drive circuit is used to control the conduction 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. The protection circuit is used to prevent damage to the NMOS transistor and misconduction in the event of ground drift.

Description

Technical Field

[0001] The present invention belongs to the technical field of electronic circuits, and in particular relates to a vehicle brushed DC motor drive protection circuit, electronic equipment, and a vehicle. Background Art

[0002] Vehicles use various motors, each driven by a driver circuit. In systems using brushed DC motors, a single driver circuit is often used. Furthermore, ground line drift can easily cause the motor to malfunction and damage the N-metal-oxide-semiconductor (NMOS) circuit. Summary of the Invention

[0003] An object of the present invention is to provide a vehicle brushed DC motor drive protection circuit, electronic equipment and vehicle, which can solve the technical problems in the prior art of low reliability of the drive circuit and the easy occurrence of motor erroneous opening and damage to NMOS when ground drift occurs.

[0004] According to a first aspect of the present invention, there is provided a vehicle brushed DC motor drive protection circuit, comprising an NMOS transistor, a drive circuit, and a protection circuit;

[0005] The drain of the NMOS transistor is connected to the motor power supply voltage, the source of the NMOS transistor is connected to one end of the motor, and the other end of the motor is connected to the power ground, and the NMOS transistor is used to drive the motor;

[0006] The gate of the NMOS transistor is connected to a first drive signal and the drive circuit respectively, one end of the drive circuit is connected to a system ground, and the drive circuit is used to control the conduction state of the NMOS transistor;

[0007] The protection circuit is connected to the driving circuit and the second driving signal respectively, and one end of the protection circuit is connected to the system ground. The protection circuit is used to prevent the NMOS transistor from being damaged and mis-conducted when a ground line drift occurs.

[0008] Optionally, the driving circuit includes a composite transistor, and the composite transistor includes a first transistor and a second transistor;

[0009] 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 end of the third resistor and the first end of the 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.

[0010] Optionally, the base of the second transistor is connected to the emitter of the second transistor and a power ground respectively, and the second transistor is used to prevent reverse connection.

[0011] Optionally, the driving circuit further includes a first capacitor, and two ends of the first capacitor are respectively connected to two ends of the fourth resistor.

[0012] Optionally, the driving circuit further includes a second capacitor, a first terminal of the second capacitor is connected to the emitter of the second transistor, and a second terminal of the second capacitor is connected to the system ground.

[0013] Optionally, the first transistor is an NPN transistor, and the second transistor is a PNP transistor.

[0014] Optionally, 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 respectively connected to the first end of the first resistor, the first end of the second resistor, and the second end of the third resistor, 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.

[0015] Optionally, the third transistor is an NPN transistor.

[0016] According to a second aspect of the present invention, an electronic device is provided, comprising the vehicle brushed DC motor drive protection circuit according to the first aspect of the present invention.

[0017] According to a third aspect of the present invention, a vehicle is provided, comprising the electronic device according to the second aspect of the present invention.

[0018] The present invention has the beneficial effect of implementing AND logic through the protection circuit and the drive circuit to jointly drive the motor. The motor is turned on only when both the first drive signal and the second drive signal are at a high level, thereby improving reliability. Furthermore, when ground drift occurs, the drift voltage generated at the first drive signal terminal can be suppressed to a low level of the power ground, thereby preventing false turn-on and preventing damage to the NMOS transistor caused by ground drift. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The diagram is a schematic diagram of a vehicle brushed DC motor drive protection circuit according to an embodiment of the present invention. DETAILED DESCRIPTION

[0020] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangement of components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention.

[0021] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0022] Techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and apparatus should be considered part of the specification. In all examples shown and discussed herein, any specific values should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0023] It should be noted that like reference numerals and letters refer to like items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0024] In the present description, references to features referred to as "first" or "second" may explicitly or implicitly include one or more of these features. In the present description, unless otherwise specified, "plurality" means two or more. Furthermore, the term "and / or" in this specification refers to at least one of the connected entities, and the character " / " generally indicates an "or" relationship between the connected entities.

[0025] This embodiment introduces a vehicle brushed DC motor drive protection circuit, including an NMOS transistor, a drive circuit, and a protection circuit.

[0026] The drain of the NMOS transistor is connected to the motor power supply voltage VB_MOT, the source of the NMOS transistor is connected to one end of the motor, and the other end of the motor is connected to the power ground. The NMOS transistor is used to drive the motor.

[0027] The gate of the NMOS transistor is connected to a first driving signal and the driving circuit respectively. One end of the driving circuit is connected to a system ground. The driving circuit is used to control the conduction state of the NMOS transistor.

[0028] The protection circuit is connected to the driving circuit and the second driving signal respectively, and one end of the protection circuit is connected to the system ground. The protection circuit is used to prevent the NMOS transistor from being damaged and mis-conducted when a ground line drift occurs.

[0029] Vehicle chassis controllers, such as those for ABS (Antilock Brake System) and ESC (Electronic Stability Control), typically have multiple ground loops within their control units, such as digital ground, logic ground, and power ground. Different hardware solutions require different ground circuits. In this disclosure, low-current grounds such as logic ground and digital ground are collectively referred to as system ground (GND). The ground for the brushed motor is separate from the system ground and is referred to as power ground (GND_P).

[0030] The first drive signal is connected to the gate of the NMOS transistor, providing a turn-on voltage to the NMOS transistor. A drive circuit is also connected to the gate of the NMOS transistor and can be used to lower the gate voltage of the NMOS transistor, turning it off. By controlling the state of the drive circuit, the NMOS transistor is turned on or off.

[0031] The second driving signal is connected to the protection circuit, which can control the state of the protection circuit, and then control the state of the driving circuit according to the state of the protection circuit, and control the conduction or shutdown of the NMOS transistor through the protection circuit and the driving circuit together.

[0032] The first drive signal is connected to the ASIC or high-side driver chip, and the second drive signal is connected to the IO interface of the MCU. The MCU, ASIC or high-side driver chip all use the system ground as the reference ground.

[0033] like Figure 1 As shown, the driving circuit includes a composite transistor, and the composite transistor includes a first transistor Q02A and a second transistor Q02B.

[0034] 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 connected to the first end of the third resistor R03 and the first end of the fourth resistor R04, respectively, 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.

[0035] The base of the second transistor Q02B is connected to the emitter of the second transistor Q02B and the power ground respectively. The second transistor is used to prevent reverse connection.

[0036] The driving circuit further includes a first capacitor C01 , and two ends of the first capacitor C01 are respectively connected to two ends of the fourth resistor R04 .

[0037] The driving circuit further includes a second capacitor C02 , a first terminal of the second capacitor C02 is connected to the emitter of the second transistor Q02B, and a second terminal of the second capacitor C02 is connected to the system ground.

[0038] The first transistor is an NPN transistor, and the second transistor is a PNP transistor.

[0039] like Figure 1 As shown, GND represents the system ground, and GND_P represents the power ground. When the first drive signal MOT_CTRL1 is high, when the first transistor Q02A is turned on, the first drive signal MOT_CTRL1 is pulled down to a low level, preventing the motor from starting. When the first transistor Q02A is turned off, the first drive signal MOT_CTRL1 level is not affected; the first drive signal MOT_CTRL1 is high, and the motor starts. When the first drive signal MOT_CTRL1 is low, the motor shuts down. The third resistor R03 is a current-limiting resistor to prevent excessive base current in the transistor.

[0040] The second transistor Q02B is used to protect against reverse polarity. Under normal operation, the collector voltage of the second transistor Q02B is greater than the emitter voltage, turning on the second transistor Q02B. In the event of reverse polarity, the negative voltage passes through the internal diode of the NMOS transistor, causing the emitter voltage of the second transistor Q02B to exceed the collector voltage, turning off the second transistor Q02B and protecting the internal circuitry.

[0041] like Figure 1 As shown, the protection circuit includes a third transistor Q01. The base of the third transistor Q01 is connected to the second drive signal MOT_CTRL2. The emitter of the third transistor Q01 is connected to the system ground. The collector of the third transistor Q01 is 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, respectively. The second end of the second resistor R02 is connected to the system ground, and the second end of the first resistor R01 is connected to the system power supply VCC. The third transistor is an NPN transistor.

[0042] The second drive signal MOT_CTRL2 is used to control the conduction state of the third transistor Q01. When the second drive signal MOT_CTRL2 is at a high level, the third transistor Q01 is turned on, turning off the first transistor Q02A. This does not affect the level of the first drive signal MOT_CTRL1. In this case, if the first drive signal MOT_CTRL1 is also at a high level, the motor starts.

[0043] If the first drive signal MOT_CTRL1 is at a high level and the second drive signal MOT_CTRL2 is at a low level, the third transistor Q01 is turned off, and the system power supply VCC is divided by the first resistor R01 and the second resistor R02. The voltage generated after the division passes through the third resistor R03, turning on the first transistor Q02A, thereby pulling the first drive signal MOT_CTRL1 down to a low level.

[0044] The motor can only be started when both the first drive signal MOT_CTRL1 and the second drive signal MOT_CTRL2 are at a high level. When either of them is at a low level, the motor drive can be turned off, thereby improving system reliability.

[0045] The above analysis is based on the assumption that the ground line does not drift. If the ground line drifts, the ground line drift in the ON state will not affect the motor opening, but it will easily cause the NMOS transistor V DS and V GS Overvoltage damage. In the OFF state, it is easy to cause false turn-on, resulting in damage to the NMOS transistor.

[0046] Because the MCU, ASIC, or high-side driver chip, and VCC all use the system ground as a reference ground, when ground drift occurs, GND > GND_P. Without a protection circuit, when the drift voltage exceeds the NMOS transistor's turn-on voltage, the first drive signal MOT_CTRL1, while at a low level relative to the system ground, is at a high voltage relative to the power ground GND_P, which can turn on the NMOS transistor. This can easily cause mis-conduction. Furthermore, the drift voltage is not a stable voltage. When the voltage is unstable, it can easily cause the NMOS transistor to enter the amplification range, causing damage to the NMOS transistor.

[0047] However, if a protection circuit is provided, a large ground offset occurs when the first drive signal MOT_CTR1 and the second drive signal MOT_CTR2 are at a low level relative to the system ground. The third transistor Q01 is turned off, the first transistor Q02A is turned on, and the second transistor Q02B is turned on. Because the base and emitter of the second transistor Q02B are connected to the power ground GND_P, the drift voltage generated at the end of the first drive signal MOT_CTR1 will be suppressed to the power ground level due to the conduction of the first transistor Q02A and the second transistor Q02B. False turn-on will not occur, and the NMOS will not be damaged due to ground offset.

[0048] The present invention implements AND logic through a protection circuit and a drive circuit to jointly drive the motor. The motor is turned on only when both the first drive signal and the second drive signal are at a high level, thereby improving reliability. Furthermore, when ground drift occurs, the drift voltage generated by the first drive signal terminal can be suppressed to a low level of the power ground, preventing false turn-on and NMOS damage caused by ground drift.

[0049] This embodiment introduces an electronic device, including a vehicle brushed DC motor drive protection circuit as described in any embodiment of the present invention.

[0050] This embodiment introduces a vehicle, comprising an electronic device described in any embodiment of the present invention.

[0051] Although some specific embodiments of the present invention have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present invention. It should be understood by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present invention.

[0052] Those skilled in the art will appreciate that the modules and algorithm steps described in conjunction with the embodiments disclosed herein can be implemented using electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present invention.

[0053] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described devices and equipment can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0054] In the embodiments provided in this 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 schematic. For example, the division of the modules is merely a logical function division. In actual implementation, there may be other division methods, such as 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 mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or modules, which can be electrical, mechanical or other forms.

[0055] The modules described as separate components may or may not be physically separate, and the components shown as modules may or may not be physical modules, that is, they may be located in one place or distributed across multiple network modules. Some or all of these modules may be selected according to actual needs to achieve the objectives of the embodiments of the present invention.

[0056] In addition, each functional module in the embodiment of the present invention may be integrated into one processing module, or each module may exist physically separately, or two or more modules may be integrated into one module.

[0057] If the functions are implemented in the form of software modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the portion that contributes to the prior art, or the portion 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 can be a personal computer, server, or 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 that can store program code, such as USB flash drives, mobile hard drives, ROM, RAM, magnetic disks, or optical disks.

[0058] The above description is merely a preferred embodiment of the present application and an illustration of the technical principles employed. Those skilled in the art should understand that the scope of the invention herein is not limited to the technical solutions formed by the specific combination of the above-mentioned technical features, but also encompasses other technical solutions formed by any combination of the above-mentioned technical features or their equivalents without departing from the inventive concept. For example, a technical solution formed by replacing the above-mentioned features with (but not limited to) technical features having similar functions disclosed in this application.

[0059] It should be understood that the size of the serial numbers of the steps in the content of the invention and the embodiments of the present invention does not absolutely mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention. The foregoing description of the implementation of the present disclosure has been given for the purpose of example and description. The foregoing description is not exhaustive and is not intended to limit the present disclosure to the exact form disclosed. Various variations and modifications may exist based on the above teachings, or various variations and modifications may be obtained from the practice of the present disclosure. These embodiments are selected and described in order to illustrate the principles of the present disclosure and its practical application, so that those skilled in the art can utilize the present disclosure in various embodiments and various modifications suitable for the specific purpose conceived.

Claims

1. A vehicle brushed DC motor drive protection circuit, characterized in that: Including NMOS transistor, drive circuit, protection circuit; The drain of the NMOS transistor is connected to the motor power supply voltage, the source of the NMOS transistor is connected to one end of the motor, and 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 conduction state of the NMOS transistor; the first drive signal is used to provide a conduction voltage to the NMOS transistor; The protection circuit is connected to the drive circuit and the second drive signal respectively, and one end of the protection circuit is connected to the system ground. The protection circuit is used to prevent the NMOS transistor from being damaged and mis-conducted in the event of ground drift; The driving 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 end of a third resistor and the first end of 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; 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 respectively connected to the first end of the first resistor, the first end of the second resistor, and the second end of the third resistor, 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; When the first drive signal is at a high level, when the first transistor is turned on, the first drive signal is pulled down to a low level, causing the motor to fail to start; when the first transistor is turned off, the first drive signal level is not affected, the first drive signal is at a high level, and the motor starts; When the first drive signal and the second drive signal are at a low level relative to the system ground, a large ground offset occurs, the third transistor is turned off, the first transistor is turned on, and the second transistor is turned on. Because the base and emitter of the second transistor are connected to the power ground, the drift voltage generated at the first drive signal end will be suppressed to the power ground level due to the conduction of the first transistor and the second transistor.

2. A vehicle brushed DC motor drive protection circuit according to claim 1, characterized in that: The base of the second transistor is connected to the emitter of the second transistor and a power ground respectively, and the second transistor is used for preventing reverse connection.

3. The vehicle brushed DC motor drive protection circuit according to claim 1, characterized in that: The driving circuit further includes a first capacitor, and two ends of the first capacitor are respectively connected to two ends of the fourth resistor.

4. The vehicle brushed DC motor drive protection circuit according to claim 1, characterized in that: The driving circuit further includes a second capacitor, a first terminal of the second capacitor is connected to the emitter of the second transistor, and a second terminal of the second capacitor is connected to the system ground.

5. The vehicle brushed DC motor drive protection circuit according to claim 1, characterized in that: The first transistor is an NPN transistor, and the second transistor is a PNP transistor.

6. The vehicle brushed DC motor drive protection circuit according to claim 1, characterized in that: The third transistor is an NPN transistor.

7. An electronic device, characterized in that: A vehicle brushed DC motor drive protection circuit comprising the circuit described in any one of claims 1 to 6.

8. A vehicle, characterized in that: An electronic device comprising the electronic device described in claim 7.

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