Pedal folding motor driving circuit meeting functional safety
By adding a drive status detection module and a drive motor power control module to the pedal folding motor drive circuit, the risk of unanticipated folding of the pedal folding motor in the prior art is solved, and a higher safety level is achieved and cost is reduced.
Patent Information
- Application Number
- CN202420958501.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-06
- Publication Date
- 2025-02-07
- Estimated Expiration
- 2034-05-06
AI Technical Summary
In the prior art, the driving method of the pedal folding motor has the risk of unanticipated folding, resulting in abnormal control of the driver on the vehicle and the cost increases when the safety level is increased.
Design a circuit including a vehicle controller MCU, a driving chip and a folding motor, through series resistance on the connecting line between the driving chip and the folding motor and the connecting line between the folding motor and the power supply ground, and using a driving state detection module and a driving motor The power ground control module monitors the output voltage of the drive chip and controls the ground return channel of the motor current to ensure the safe operation of the motor.
With this circuit structure, the safety level of the pedal folding motor can be improved without using a high-level driver chip, avoid unexpected folding, and reduce hardware costs.
Smart Images
Figure CN222441345U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of automobile technology, and in particular to a pedal folding motor driving circuit. Background Art
[0002] With the continuous development of automobile technology, people have higher requirements for riding comfort. Currently, some cars are equipped with an accelerator pedal folding function to free up leg room for the driver when he is resting.
[0003] The existing pedal folding motor driving method is to connect the positive and negative poles of the folding motor to the two output channels of the motor driver chip. After receiving the motor folding request, the vehicle controller MCU performs SPI communication / IO control on the driver chip. The driver chip changes the internal MOS conduction state, and the two output channels are respectively connected to the power supply and the ground to form an H bridge to drive the motor folding / unfolding action.
[0004] However, implementing the pedal folding function will introduce certain driving risks, such as the unexpected folding of the accelerator pedal during normal driving (when the pedal request is not true), which may cause the driver to have abnormal control over the vehicle, thereby causing traffic accidents and even casualties. Figure 1 As shown, the motor driver chip output current feedback function is generally used, and the MCU determines whether the pedal folding motor action is as expected based on this function. It also has overvoltage / overcurrent / overheating protection functions to protect the chip when the motor drive is abnormal, and feedback the fault status to the MCU. However, when the driver chip current detection function fails or the driver chip control function fails, there is no other way to prevent the motor from unexpectedly moving, which makes the safety level of unexpected pedal folding low, increasing the risk of abnormal vehicle control by the driver.
[0005] Moreover, the technology must first avoid failures in the current detection function of the driver chip or the control function of the driver chip, so as to increase the functional safety level for preventing unexpected folding of the pedal folding motor. A higher-level driver chip (meeting functional safety ASIL-D) is required to meet the functional safety design requirements. The hardware cost will be higher and the chip selection range will be smaller. Utility Model Content
[0006] Based on this, in response to the above technical problems, a pedal folding motor drive circuit that meets functional safety is provided to solve the problem that the existing technology makes the pedal folding safety level low, or the problem that the existing technology achieves a higher safety level for the pedal folding, but the cost increases.
[0007] A pedal folding motor driving circuit that meets functional safety, the circuit comprising: a vehicle controller MCU, a driving chip, and a folding motor;
[0008] The first output terminal of the vehicle controller MCU is connected to the first input terminal of the driver chip to perform SPI communication or IO control; the first output terminal and the second output terminal of the driver chip are respectively connected to the first input terminal and the second input terminal of the vehicle controller MCU; the third output terminal OUT1 and the fourth output terminal OUT2 of the driver chip are respectively connected to the two ends of the folding motor; the fifth output terminal of the driver chip is connected to the power ground;
[0009] The circuit also includes: a driving state detection module and a driving motor power control module;
[0010] The driving state detection module includes: a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, and a resistor R6; a first node is set on the connection line between the third output terminal OUT1 of the driving chip and the folding motor, and a first branch is led out from the first node, and the first branch is connected to the power ground after sequentially connecting the resistor R1 and the resistor R2 in series; a second node is set on the connection line between the resistor R1 and the resistor R2, and a second branch is led out from the second node to connect to the third input terminal of the vehicle controller MCU;
[0011] A third node is set between the fourth output terminal OUT2 of the driving chip and the connection line of the folding motor, and a third branch is led out from the third node. The third branch is connected to the power ground after being connected in series with the resistor R3 and the resistor R4 in sequence; a fourth node is set on the connection line of the resistor R3 and the resistor R4, and a fourth branch is led out from the fourth node to connect to the third input terminal of the vehicle controller MCU;
[0012] A fifth node is set on the connection line between the fifth output terminal of the driver chip and the power ground, a fifth branch is led out from the fifth node, and the fifth branch is connected to the power ground after being connected in series with the resistor R5 and the resistor R6 in sequence; a sixth node is set on the connection line between the resistor R5 and the resistor R6, and a sixth branch is led out from the sixth node to connect to the third input terminal of the vehicle controller MCU;
[0013] The drive motor power control module includes a transistor Q1, a transistor Q2 and a MOS transistor Q3; the collector of the transistor Q1 is connected to the base of the transistor Q2, the base of the transistor Q1 is connected to the second output end of the vehicle controller MCU, and the emitter collector of the transistor Q1 is grounded; the collector of the transistor Q2 is connected to the gate of the MOS transistor Q3, and the MOS transistor Q3 is connected between the fifth node and the power ground.
[0014] In the above scheme, optionally, the resistance value of the resistor R1 is 100KΩ, the resistance value of the resistor R2 is 10KΩ, the resistance value of the resistor R3 is 100KΩ, the resistance value of the resistor R4 is 10KΩ, the resistance value of the resistor R5 is 100KΩ, and the resistance value of the resistor R6 is 10KΩ.
[0015] In the above solution, optionally, the emitter of the transistor Q2 is externally connected to the vehicle battery.
[0016] In the above solution, optionally, the model of the driver chip is DRV8243-Q1.
[0017] In the above solution, optionally, the model of the transistor Q1 is MMUN2233LT1G, and the model of the transistor Q2 is MMUN2114LT1G.
[0018] This application has at least the following beneficial effects:
[0019] This application connects two resistors in series on the connection line between the driver chip and the folding motor and the connection line between the folding motor and the power ground, and the input port of the A\D acquisition of the vehicle controller MCU is connected between the two resistors in series, so that the output voltage of the driver chip is fed back to the MCU for monitoring through resistor voltage division, thereby judging the running state of the motor. When the current feedback function of the driver chip is impaired, the output voltage of the driver chip is obtained through the driving state detection circuit, and it is increased to a safety level that causes unexpected folding of the pedal.
[0020] At the same time, an N-type MOS tube is connected in series between the ground pin of the driver chip and the system ground to control the switch of the ground return channel of the motor current. When the MCU does not recognize that the folding motor is operating without receiving a request, it outputs a low level to the MOS tube and switches the MOS tube to the off state, thereby ensuring that the motor will not fold abnormally when the control function of the driver chip fails. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 It is a schematic diagram of the circuit structure of the prior art;
[0022] Figure 2 A circuit structure schematic diagram of a pedal folding motor driving circuit that meets functional safety is provided for one embodiment of the present application;
[0023] Figure 3 A schematic diagram of control relationship and feedback relationship of a pedal folding motor drive circuit that meets functional safety is provided for one embodiment of the present application. DETAILED DESCRIPTION
[0024] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.
[0025] In one embodiment, Figure 2 As shown, a pedal folding motor driving circuit that meets functional safety, the circuit includes: a vehicle controller MCU, a driving chip, and a folding motor;
[0026] The first output end of the vehicle controller MCU is connected to the first input end of the driver chip for SPI communication or IO control; the first output end and the second output end of the driver chip are respectively connected to the first input end and the second input end of the vehicle controller MCU; the third output end OUT1 and the fourth output end OUT2 of the driver chip are respectively connected to the two ends of the folding motor; the fifth output end of the driver chip is connected to the power ground.
[0027] Specifically, Figure 1 As shown, in the prior art, the first output terminal of the vehicle controller MCU is connected to the first input terminal of the driver chip for SPI communication or IO control; at the same time, the first output terminal of the driver chip is connected to the first input terminal of the vehicle controller MCU for current feedback, and the second output terminal of the driver chip is connected to the second input terminal of the vehicle controller MCU for obstacle feedback. In addition, it also includes a connection port for enabling the vehicle controller MCU and the driver chip.
[0028] The circuit also includes: a driving state detection module and a driving motor power control module;
[0029] The driving state detection module includes: a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, and a resistor R6; a first node is set on the connection line between the third output terminal OUT1 of the driving chip and the folding motor, and a first branch is led out from the first node, and the first branch is connected to the power ground after sequentially connecting the resistor R1 and the resistor R2 in series; a second node is set on the connection line between the resistor R1 and the resistor R2, and a second branch is led out from the second node to connect to the third input terminal of the vehicle controller MCU;
[0030] A third node is set between the fourth output terminal OUT2 of the driving chip and the connection line of the folding motor, and a third branch is led out from the third node. The third branch is connected to the power ground after being connected in series with the resistor R3 and the resistor R4 in sequence; a fourth node is set on the connection line of the resistor R3 and the resistor R4, and a fourth branch is led out from the fourth node to connect to the third input terminal of the vehicle controller MCU;
[0031] A fifth node is set on the connection line between the fifth output terminal of the driver chip and the power ground, a fifth branch is led out from the fifth node, and the fifth branch is connected to the power ground after being connected in series with the resistor R5 and the resistor R6; a sixth node is set on the connection line between the resistor R5 and the resistor R6, and a sixth branch is led out from the sixth node to connect to the third input terminal of the vehicle controller MCU;
[0032] The drive motor power control module includes a transistor Q1, a transistor Q2 and a MOS transistor Q3; the collector of the transistor Q1 is connected to the base of the transistor Q2, the base of the transistor Q1 is connected to the second output end of the vehicle controller MCU, and the emitter collector of the transistor Q1 is grounded; the collector of the transistor Q2 is connected to the gate of the MOS transistor Q3, and the MOS transistor Q3 is connected between the fifth node and the power ground.
[0033] Specifically, the technical problem to be solved by the utility model is: without using a motor driver chip that meets the functional safety ASIL-D, by adding a chip peripheral protection circuit, the entire motor drive structure reaches the functional safety level ASIL-D. To achieve the above original intention, the motor drive structure provided by the utility model adds the following two circuit modules compared with the prior art:
[0034] 1) Drive status monitoring module: The working principle of this module is to feed back the output voltage of the driver chip to the MCU for monitoring through resistor voltage division, so as to determine the running status of the motor. When the motor is not running, the voltage feedback of OUT1 and OUT2 are both 0V; when the motor is running, the voltage feedback of the upper bridge arm will become a high level (compared with the existing technology, the motor status continues to be monitored when the current feedback function of the driver chip fails); the power ground status monitoring can directly feed back the grounding status of the driver chip to the MCU, improving system reliability.
[0035] 2) Drive motor power ground control module: The main working principle of this module is to connect an N-type MOS tube in series between the ground pin of the driver chip and the system ground, so as to switch the return channel of the motor current. When the system MCU is working normally, if it is recognized that the folding motor is operating without receiving a request (when the driver chip control function fails and cannot receive a request), the MCU_GPIO can output a low level to switch the MOS tube to the off state, thereby preventing the accelerator pedal from folding abnormally (compared with the existing technology, it can ensure that the motor does not fold abnormally when the driver chip control function fails).
[0036] The above-mentioned pedal folding motor driving circuit that meets functional safety is connected in series with two resistors on the connection line between the driver chip and the folding motor and the connection line between the folding motor and the power ground, and the input port of the A\D acquisition of the vehicle controller MCU is connected between the two resistors in series, so that the output voltage of the driver chip is fed back to the MCU for monitoring through resistor voltage division, thereby judging the motor operation status. When the current feedback function of the driver chip is impaired, the output voltage of the driver chip is obtained through the driving state detection circuit, and is increased to a safety level that causes unexpected pedal folding.
[0037] At the same time, an N-type MOS tube is connected in series between the ground pin of the driver chip and the system ground to control the switch of the ground return channel of the motor current. When the MCU does not recognize that the folding motor is operating without receiving a request, it outputs a low level to the MOS tube and switches the MOS tube to the off state, thereby ensuring that the motor will not fold abnormally when the control function of the driver chip fails.
[0038] In one embodiment, the resistance value of the resistor R1 is 100KΩ, the resistance value of the resistor R2 is 10KΩ, the resistance value of the resistor R3 is 100KΩ, the resistance value of the resistor R4 is 10KΩ, the resistance value of the resistor R5 is 100KΩ, and the resistance value of the resistor R6 is 10KΩ.
[0039] In one embodiment, the emitter of the transistor Q2 is externally connected to a vehicle battery.
[0040] In one embodiment, the model of the driver chip is DRV8243-Q1.
[0041] In one embodiment, the model of the transistor Q1 is MMUN2233LT1G, and the model of the transistor Q2 is MMUN2114LT1G.
[0042] The utility model Figure 3 As shown, through the driving state monitoring circuit and the driving motor power control circuit, when the current feedback module of the driving chip fails, the output current reliability of the driving chip is fed back to the MCU in time, and when the driving chip fails, it is ensured that the motor will not be driven.
[0043] The existing MCU and driver chip are single-channel control and feedback. When the control or feedback function of the driver chip fails, the pedal motor is very likely to act unexpectedly, affecting functional safety. The utility model provides an additional control and feedback channel. When the driver chip fails, the module circuit can be used to effectively avoid the pedal motor from folding unexpectedly.
[0044] If the existing technology is to meet the functional safety level ASIL-D, it is necessary to select a higher-level driver chip, which is easily restricted during selection; the utility model reduces the design cost while meeting the functional safety requirements, while improving the overall reliability and safety of the system.
[0045] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0046] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the utility model patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.
Claims
1. A pedal folding motor driving circuit meeting functional safety, the circuit comprising: Vehicle controller MCU, driver chip, folding motor; The first output terminal of the vehicle controller MCU is connected to the first input terminal of the driver chip to perform SPI communication or IO control; the first output terminal and the second output terminal of the driver chip are respectively connected to the first input terminal and the second input terminal of the vehicle controller MCU; the third output terminal OUT1 and the fourth output terminal OUT2 of the driver chip are respectively connected to the two ends of the folding motor; the fifth output terminal of the driver chip is connected to the power ground; Characterized in that the circuit further comprises: a driving state detection module and a driving motor power control module; The driving state detection module includes: a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, and a resistor R6; a first node is set on the connection line between the third output terminal OUT1 of the driving chip and the folding motor, and a first branch is led out from the first node, and the first branch is connected to the power ground after sequentially connecting the resistor R1 and the resistor R2 in series; a second node is set on the connection line between the resistor R1 and the resistor R2, and a second branch is led out from the second node to connect to the third input terminal of the vehicle controller MCU; A third node is set between the fourth output terminal OUT2 of the driving chip and the connection line of the folding motor, and a third branch is led out from the third node. The third branch is connected to the power ground after being connected in series with the resistor R3 and the resistor R4 in sequence; a fourth node is set on the connection line of the resistor R3 and the resistor R4, and a fourth branch is led out from the fourth node to connect to the third input terminal of the vehicle controller MCU; A fifth node is set on the connection line between the fifth output terminal of the driver chip and the power ground, a fifth branch is led out from the fifth node, and the fifth branch is connected to the power ground after being connected in series with the resistor R5 and the resistor R6 in sequence; a sixth node is set on the connection line between the resistor R5 and the resistor R6, and a sixth branch is led out from the sixth node to connect to the third input terminal of the vehicle controller MCU; The drive motor power control module includes a transistor Q1, a transistor Q2 and a MOS transistor Q3; the collector of the transistor Q1 is connected to the base of the transistor Q2, the base of the transistor Q1 is connected to the second output end of the vehicle controller MCU, and the emitter collector of the transistor Q1 is grounded; the collector of the transistor Q2 is connected to the gate of the MOS transistor Q3, and the MOS transistor Q3 is connected between the fifth node and the power ground.
2. The pedal folding motor driving circuit meeting functional safety according to claim 1, characterized in that: The resistance value of the resistor R1 is 100KΩ, the resistance value of the resistor R2 is 10KΩ, the resistance value of the resistor R3 is 100KΩ, the resistance value of the resistor R4 is 10KΩ, the resistance value of the resistor R5 is 100KΩ, and the resistance value of the resistor R6 is 10KΩ.
3. The pedal folding motor driving circuit meeting functional safety according to claim 1, characterized in that: The emitter of the transistor Q2 is externally connected to the vehicle battery.
4. The pedal folding motor driving circuit meeting functional safety according to claim 1, characterized in that: The model of the driver chip is DRV8243-Q1.
5. The pedal folding motor driving circuit meeting functional safety according to claim 1, characterized in that: The model of the transistor Q1 is MMUN2233LT1G, and the model of the transistor Q2 is MMUN2114LT1G.