A protection circuit for an automobile seat motor

Abstract

The utility model provides a kind of protection circuit of automobile seat motor, when seat is connected power supply, 12V power supply is given to MCU power supply on one hand, and the other hand is given motor drive chip power supply;MCU and drive chip are monitored motor operating state by SPI communication between, and MCU controls drive chip work and non-work and controls working mode etc. state;Drive chip is in enabling work and output PWM mode state, and drive four groups of MOS pipe group's H bridge controls backrest motor, seat cushion motor, leg support motor, slide rail motor realizes positive and negative rotation;While the current that flows through current sampling resistance changes into voltage signal input to drive chip, drive chip judges motor's locked-rotor current to realize motor switch-off and work, to reach the purpose of protecting motor.

Description

Technical Field

[0001] This utility model belongs to the field of seat motor circuit technology, and in particular relates to a protection circuit for an automotive seat motor. Background Technology

[0002] As cars become increasingly common, consumers have higher and higher demands. In addition to price, people are paying more and more attention to the safety and comfort of cars. Car seats are not only key to improving passenger comfort, but also a crucial technology for developing high-quality car seats and forming a competitive edge in the car seat market.

[0003] Existing car seat motors lack protection when driving the seat, resulting in a reduced motor lifespan. Therefore, this invention proposes a motor drive and protection circuit for controlling a car seat motor, which can realize the functions of driving and protecting the car seat motor. Utility Model Content

[0004] This invention provides a protection circuit for an automotive seat motor, aiming to solve the problems mentioned in the background art.

[0005] This utility model is implemented as follows: a protection circuit for an automotive seat motor, including an MCU control circuit, a motor drive circuit, and an H-bridge control and stall current protection circuit.

[0006] The MCU control circuit includes a 3.3V power supply filter circuit, a reset circuit, an SPI communication circuit, and an enable and mode selection circuit. The 3.3V power supply filter circuit is used to provide a stable and reliable 3.3V power supply for the MCU. The reset circuit is used to reset the MCU in case of startup / abnormality. The SPI communication circuit is used for data communication with the driver chip. The enable and mode selection circuit is used to enable and select the mode of the driver chip.

[0007] The motor drive circuit includes a power supply unit, an SPI communication unit, a high-side and low-side gate drive unit, an enable unit, a sleep unit, and a watchdog fault status unit. The power supply unit supplies power to the drive chip through the PVDD pin. The SPI communication unit is used for data communication with the MCU control circuit. The high-side and low-side gate drive unit is used to output the PWM pulse width wave of the drive backend. The logic of the enable unit is used in conjunction with the MODE. When the sleep unit is pulled low, the motor drive circuit is in a sleep state. When a watchdog fault occurs, the watchdog fault status unit is pulled low.

[0008] The H-bridge control and stall current protection circuit includes an H-bridge circuit and a current sampling circuit composed of resistors, wherein the H-bridge circuit is composed of four MOS transistors and the current sampling circuit includes resistors R74 and R75.

[0009] The SPI communication unit in the motor drive circuit includes SCLK, SDO, SDI and SCS, which are used to communicate with the MCU control circuit so that the MCU can monitor the status of the drive motor in real time and turn the drive chip drive function on or off.

[0010] The high-side and low-side gate driving units include GH1, GH2, GL1 and GL2, which are used to output the PWM pulse width wave driving the back end;

[0011] The enabling unit includes enabling PH / IN1 and enabling EH / IN2. When the mode MODE is pulled to a logic low level, the enabling unit is in control mode. When the mode MODE is pulled to a logic high level, the enabling unit is in half-bridge mode. When the mode MODE is left floating, the enabling unit is in PWM control mode. When power is applied or the sleep mode is exited, the mode MODE pin is locked, and MODE is connected to an internal pull-up or pull-down resistor.

[0012] The sleep unit is nSLEEP. When nSLEEP is pulled low, the motor drive circuit is in sleep mode.

[0013] The H-bridge circuit includes Q9MOS transistor, Q10MOS transistor, Q11MOS transistor and Q12MOS transistor, wherein Q9MOS transistor and Q11MOS transistor form one bridge arm, and Q10MOS transistor and Q12MOS transistor form another bridge arm.

[0014] Compared with the prior art, the beneficial effects of this utility model are:

[0015] When the seat is powered on, the 12V power supply powers both the MCU and the motor driver chip. The MCU and driver chip communicate via SPI to monitor the motor's operating status. Simultaneously, the MCU controls the driver chip's operation and non-operation status, as well as its operating mode. In enabled and PWM output modes, the driver chip drives an H-bridge composed of four MOSFETs to control the backrest motor, seat cushion motor, leg rest motor, and slide rail motor to achieve forward and reverse rotation. At the same time, the current flowing through the current sampling resistor is converted into a voltage signal and input to the driver chip. The driver chip determines the motor's stall current and shuts off or restarts the motor, thereby protecting it. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the motor drive circuit in this utility model;

[0017] Figure 2 This is a schematic diagram of the H-bridge control and stall current protection circuit in this utility model. Detailed Implementation

[0018] The technical solution of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of this utility model, but not all embodiments.

[0019] The components of the present invention embodiments described and shown in the accompanying drawings can typically be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention.

[0020] Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0021] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0022] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0023] This utility model provides a technical solution: a protection circuit for an automotive seat motor, including an MCU control circuit, a motor drive circuit, and an H-bridge control and stall current protection circuit;

[0024] The MCU control circuit includes a 3.3V power supply filter circuit, a reset circuit, an SPI communication circuit, and an enable and mode selection circuit.

[0025] The 3.3V power supply filter circuit mainly provides a stable and reliable 3.3V power supply for the MCU; the reset circuit mainly resets the microcontroller in case of startup or abnormality; the SPI communication circuit mainly communicates data with the driver chip; the enable and mode selection circuit mainly enables and selects the mode of the driver chip.

[0026] See appendix Figure 1 Here is a schematic diagram of the motor drive circuit:

[0027] The motor drive circuit mainly includes a power supply unit, an SPI communication unit, high and low side gate drive units, an enable unit, a sleep unit, and a watchdog fault status unit.

[0028] The power supply unit primarily supplies power to the driver chip via the PVDD pin; the SPI communication unit (SCLK, SDO, SDI, SCS) mainly communicates with the MCU control circuit to enable the MCU to monitor the motor status in real time and turn the driver chip's driving function on or off; the high-side and low-side gate drive units (GH1, GH2, GL1, GL2) mainly output the PWM pulse width waveform of the driver backend; the enable unit (PH / IN1, EH / IN2) works in conjunction with the logic and mode selection (MODE). When the mode is pulled low... When the level is low, the PH / IN1 and EH / IN2 control modes are enabled. When the MODE pin is pulled high, the half-bridge mode is enabled. When the MODE pin is left floating, the PWM control mode is enabled. When power is applied or the sleep mode is exited, the MODE pin is locked, and the MODE pin is connected to an internal pull-up or pull-down resistor. When the sleep section (nSLEEP) is pulled low, the drive circuit is in sleep mode. In watchdog fault state (nWDFLT), when a watchdog fault occurs, nWDFLT is pulled low.

[0029] See appendix Figure 2 Here is a schematic diagram of the H-bridge control and locked-rotor current protection circuit:

[0030] The H-bridge control and locked-rotor current protection circuit mainly includes an H-bridge circuit and a current sampling circuit composed of resistors:

[0031] The H-bridge circuit consists of four MOSFETs (Q9, Q10, Q11, and Q12). Q9 and Q11 form one bridge arm, while Q10 and Q12 form the other. When the driver chip outputs PWM to turn on Q9 and Q11 (while Q10 and Q12 are off), the conduction path is VBAT_IN → Q9 → motor → Q11 → R74 / / R75 → GND. At this time, the motor rotates forward, and current flows through the sampling resistors R74 / / R75. This current is converted into a voltage signal and sent to the driver chip. The driver chip internally sets a voltage threshold; when the voltage signal exceeds the threshold, it is determined to be a stall condition. When the current flows through the sampling resistors R74 / R75, the current is converted into a voltage signal and sent to the driver chip. The driver chip has an internal voltage threshold. When the voltage signal is greater than the voltage threshold, it is judged as a stall current. At this time, the driver chip turns off the PWM output. Otherwise, it outputs the PWM normally to protect the motor. When the driver chip outputs the PWM to turn on the Q10 MOS transistor and the Q12 MOS transistor (at this time, the Q9 MOS transistor and the Q10 MOS transistor are turned off), the conduction path is VBAT_IN→Q12 MOS transistor→motor→Q10 MOS transistor→R74 / / R75→GND. At this time, the motor rotates forward, and the current flows through the sampling resistors R74 / / R75. The current is converted into a voltage signal and sent to the driver chip. The driver chip has an internal voltage threshold. When the voltage signal is greater than the voltage threshold, it is judged as a stall current. At this time, the driver chip turns off the PWM output. Otherwise, it outputs the PWM normally to protect the motor.

[0032] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A protection circuit for an automotive seat motor, characterized in that: Includes MCU control circuit, motor drive circuit, H-bridge control and stall current protection circuit; The MCU control circuit includes a 3.3V power supply filter circuit, a reset circuit, an SPI communication circuit, and an enable and mode selection circuit. The 3.3V power supply filter circuit is used to provide a stable and reliable 3.3V power supply for the MCU. The reset circuit is used to reset the MCU in case of startup / abnormality. The SPI communication circuit is used for data communication with the driver chip. The enable and mode selection circuit is used to enable and select the mode of the driver chip. The motor drive circuit includes a power supply unit, an SPI communication unit, a high-side and low-side gate drive unit, an enable unit, a sleep unit, and a watchdog fault status unit. The power supply unit supplies power to the drive chip through the PVDD pin. The SPI communication unit is used for data communication with the MCU control circuit. The high-side and low-side gate drive unit is used to output the PWM pulse width wave of the drive backend. The logic of the enable unit is used in conjunction with the MODE. When the sleep unit is pulled low, the motor drive circuit is in a sleep state. When a watchdog fault occurs, the watchdog fault status unit is pulled low. The H-bridge control and stall current protection circuit includes an H-bridge circuit and a current sampling circuit composed of resistors, wherein the H-bridge circuit is composed of four MOS transistors and the current sampling circuit includes resistors R74 and R75. The SPI communication unit in the motor drive circuit includes SCLK, SDO, SDI and SCS, which are used to communicate with the MCU control circuit so that the MCU can monitor the status of the drive motor in real time and turn the drive chip drive function on or off. The high-side and low-side gate driving units include GH1, GH2, GL1 and GL2, which are used to output the PWM pulse width wave driving the back end; The enabling unit includes enabling PH / IN1 and enabling EH / IN2. When the mode MODE is pulled to a logic low level, the enabling unit is in control mode. When the mode MODE is pulled to a logic high level, the enabling unit is in half-bridge mode. When the mode MODE is left floating, the enabling unit is in PWM control mode. When power is applied or the sleep mode is exited, the mode MODE pin is locked, and MODE is connected to an internal pull-up or pull-down resistor. The sleep unit is nSLEEP. When nSLEEP is pulled low, the motor drive circuit is in sleep mode. The H-bridge circuit includes Q9MOS transistor, Q10MOS transistor, Q11MOS transistor and Q12MOS transistor, wherein Q9MOS transistor and Q11MOS transistor form one bridge arm, and Q10MOS transistor and Q12MOS transistor form another bridge arm.

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