Universal switch state detection circuit for EPB switch and P-gear switch

Abstract

The utility model discloses a general switch state detection circuit for an EPB switch and a P-gear switch, which belongs to the field of automobile brake safety detection and comprises a switch state control real-time monitoring module for scanning and monitoring the interface state of the EPB switch or the P-gear switch in real time and an output module. The input end of the on-off state control real-time monitoring module is connected with an EPB switch or a P-gear switch, the on-off state control real-time monitoring module is connected with a digital-to-analog conversion port ADC1 of the MCU through the output module, the MCU is connected with the automobile controller, and the automobile controller is connected with the actuator. By adopting the general switch state detection circuit for the EPB switch and the P-gear switch, effective identification and verification of two different types of switches (the EPB switch or the P-gear switch) can be realized by utilizing the same set of circuit design.

Description

Technical Field

[0001] The utility model relates to the technical field of automobile brake safety detection, in particular to a universal switch state detection circuit for an EPB switch and a P gear switch. Background Art

[0002] With the widespread popularity of automatic transmission vehicles, accurate detection and efficient control of the status of the EPB (electronic parking brake) switch and P gear (parking gear) switch, key components for ensuring safe parking of vehicles, are particularly important.

[0003] The EPB switch is responsible for managing the activation and release of the electronic parking brake system, while the P position switch is responsible for securing the transmission in Park mode. If these two critical switches malfunction or their status is not accurately monitored, a series of potential safety hazards such as unexpected vehicle sliding or rolling could occur. Utility Model Content

[0004] The purpose of the utility model is to provide a universal switch state detection circuit for an EPB switch and a P gear switch to solve the above technical problems.

[0005] To achieve the above-mentioned objectives, the utility model provides a universal switch state detection circuit for an EPB switch and a P-gear switch, comprising a switch state control real-time monitoring module and an output module for real-time scanning and monitoring the interface state of the EPB switch or the P-gear switch. The input end of the switch state control real-time monitoring module is connected to the EPB switch or the P-gear switch, and the switch state control real-time monitoring module is connected to the digital-to-analog conversion port ADC1 of the microcontroller MCU via the output module. The microcontroller MCU is connected to the vehicle controller, and the vehicle controller is connected to the actuator.

[0006] Preferably, the switch state control real-time monitoring module includes a PNP transistor Q1, an NPN transistor Q2 and a voltage divider resistor R1, wherein the collector of the PNP transistor Q1 is connected to the vehicle power supply voltage terminal V1, the emitter of the PNP transistor Q1 is connected to the short circuit detection port SW2 via the voltage divider resistor R1, the base of the PNP transistor Q1 is connected to the collector of the NPN transistor Q2, the emitter of the NPN transistor Q2 is grounded, and the base of the NPN transistor Q2 is connected to the general output port GPIO1 of the microcontroller MCU via the switch state scanning control port SW1.

[0007] Preferably, the output module includes a PNP transistor Q3, an NPN transistor Q4, an NPN transistor Q5 and a voltage divider resistor R2, the base of the NPN transistor Q4 is connected to the internal driving voltage port V3, the emitter of the NPN transistor Q4 is grounded, the collector of the NPN transistor Q4 is connected to the base of the PNP transistor Q3, the collector of the PNP transistor Q3 is connected to the internal power supply voltage port V2, the emitter of the PNP transistor Q3 is connected to the base of the NPN transistor Q5, the collector of the NPN transistor Q5 is connected between the voltage divider resistor R1 and the short circuit detection port SW2, the emitter of the NPN transistor Q5 is connected in series with the voltage divider resistor R2 and then grounded, and an output signal port SW3 is also connected between the emitter of the NPN transistor Q5 and the voltage divider resistor R2, and the output signal port SW3 is connected to the digital-to-analog conversion port ADC1 of the microcontroller MCU.

[0008] Preferably, one end of a filtering energy storage capacitor C1 is further connected between the voltage dividing resistor R2 and the output signal port SW3 , and the other end of the filtering energy storage capacitor C1 is grounded.

[0009] Preferably, the EPB switch is a four-wire EPB switch, and the four state output ports of the four-wire EPB switch are respectively connected to the short circuit detection port SW2 of the four switch state control real-time monitoring modules via the external switch state input signal port SW4, the external switch state input signal port SW5, the external switch state input signal port SW6, and the external switch state input signal port SW7, respectively; the general output port GPIO1, the general output port GPIO2, the general output port GPIO3, and the general output port GPIO4 of the microcontroller MCU are respectively connected to the switch state scan control port SW1 of the four switch state control real-time monitoring modules, and the output signal port SW3 of the four output modules is respectively connected to the digital-to-analog conversion port ADC1, the digital-to-analog conversion port ADC2, the digital-to-analog conversion port ADC3, and the digital-to-analog conversion port ADC4 of the microcontroller MCU;

[0010] And the general output port GPIO1, the general output port GPIO2, the general output port GPIO3, and the general output port GPIO4 periodically output high and low levels.

[0011] Therefore, the utility model adopts the above-mentioned universal switch state detection circuit for the EPB switch and the P gear switch, which has the following beneficial effects:

[0012] 1. The same circuit design can be used to effectively identify and verify two different types of switches (EPB switch or P-shift switch), fully considering functional safety requirements. This ensures accuracy while enhancing fault tolerance. Compared with a single signal recognition solution, this multi-path parallel processing method improves system reliability and safety.

[0013] 2. By achieving highly accurate monitoring of the EPB and P gear switch status, the vehicle's current parking condition can be continuously tracked, thereby better ensuring the vehicle's stability and reliability when stationary;

[0014] 3. It can immediately notify the driver to take corresponding measures when any abnormal working conditions are found, which greatly enhances the overall driving safety;

[0015] 4. It helps to improve the design compactness of the EPB electronic system and simplify the layout of related electrical circuits.

[0016] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of a universal switch state detection circuit for an EPB switch and a P gear switch in the utility model;

[0018] Figure 2 This is a four-wire EPB switch wiring diagram of a universal switch state detection circuit for an EPB switch and a P gear switch in the utility model;

[0019] Figure 3 This is a pin diagram of a microcontroller MCU when connecting a universal switch state detection circuit for an EPB switch and a P gear switch of the utility model to a four-wire EPB switch. DETAILED DESCRIPTION

[0020] In the description of the present utility model, it should be noted that the terms "upper", "lower", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or the orientations or positional relationships in which the utility model product is usually placed when in use. They are only for the convenience of describing the present utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In the description of the present utility model, it should also be noted that, unless otherwise clearly specified and limited, the terms "setting", "installation" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be a communication between the internal parts of two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0021] The following describes the embodiments of the present invention in detail with reference to the accompanying drawings.

[0022] like Figure 1-Figure 3As shown, a universal switch state detection circuit for an EPB switch and a P-speed switch includes a switch state control real-time monitoring module and an output module for real-time scanning and monitoring the interface state of the EPB switch or the P-speed switch. The input end of the switch state control real-time monitoring module is connected to the EPB switch or the P-speed switch. The switch state control real-time monitoring module is connected to the digital-to-analog conversion port ADC1 of the microcontroller MCU via the output module. The microcontroller MCU is connected to the vehicle controller, and the vehicle controller is connected to the actuator.

[0023] Specifically, the switch state control real-time monitoring module includes a PNP transistor Q1, an NPN transistor Q2 and a voltage divider resistor R1, wherein the collector of the PNP transistor Q1 is connected to the vehicle power supply voltage terminal V1, the emitter of the PNP transistor Q1 is connected to the short-circuit detection port SW2 via the voltage divider resistor R1, the base of the PNP transistor Q1 is connected to the collector of the NPN transistor Q2, the emitter of the NPN transistor Q2 is grounded, and the base of the NPN transistor Q2 is connected to the general output port GPIO1 of the microcontroller MCU via the switch state scanning control port SW1.

[0024] The output module includes a PNP transistor Q3, an NPN transistor Q4, an NPN transistor Q5 and a voltage divider resistor R2. The base of the NPN transistor Q4 is connected to the internal driving voltage port V3, the emitter of the NPN transistor Q4 is grounded, the collector of the NPN transistor Q4 is connected to the base of the PNP transistor Q3, the collector of the PNP transistor Q3 is connected to the internal power supply voltage port V2, the emitter of the PNP transistor Q3 is connected to the base of the NPN transistor Q5, the collector of the NPN transistor Q5 is connected between the voltage divider resistor R1 and the short-circuit detection port SW2, the emitter of the NPN transistor Q5 is connected in series with the voltage divider resistor R2 and then grounded, and an output signal port SW3 is also connected between the emitter of the NPN transistor Q5 and the voltage divider resistor R2, and the output signal port SW3 is connected to the digital-to-analog conversion port ADC1 of the microcontroller MCU.

[0025] One end of a filtering energy storage capacitor C1 is further connected between the voltage dividing resistor R2 and the output signal port SW3 , and the other end of the filtering energy storage capacitor C1 is grounded.

[0026] The EPB switch is a four-wire EPB switch. The four state output ports of the four-wire EPB switch are respectively connected to the short-circuit detection port SW2 of the four switch state control real-time monitoring modules via the external switch state input signal port SW4, the external switch state input signal port SW5, the external switch state input signal port SW6, and the external switch state input signal port SW7. The general output port GPIO1, the general output port GPIO2, the general output port GPIO3, and the general output port GPIO4 of the microcontroller MCU are respectively connected to the switch state scan control port SW1 of the four switch state control real-time monitoring modules. The output signal port SW3 of the four output modules is respectively connected to the digital-to-analog conversion port ADC1, the digital-to-analog conversion port ADC2, the digital-to-analog conversion port ADC3, and the digital-to-analog conversion port ADC4 of the microcontroller MCU; and the general output port GPIO1, the general output port GPIO2, the general output port GPIO3, and the general output port GPIO4 periodically output high and low levels. In this embodiment, when the EPB switch of the automobile is in the non-actuated state, SW4 is connected to SW7 and SW5 is connected to SW6; when in the actuated state, SW4 is connected to SW5 and SW6 for a pulled-up state, and SW4 is connected to SW6 and SW7 for a released state.

[0027] Since each switch pin of the external EPB switch and the P gear switch is independent of each other, and the internal scanning detection switch signal is processed in real time, detection failure will not occur due to different external switch states. Therefore, this method avoids the false triggering problem caused by a single set of signal recognition methods, making the automotive switch recognition circuit more compliant with functional safety design specifications.

[0028] The working state of the transistors is as follows: NPN transistor Q4 is driven by the internal drive voltage port V3 and operates in the saturation region. NPN transistor Q4 is fully turned on, and the voltage drop between its collector and emitter (VCE(sat)) is very small. At this time, the base of PNP transistor Q3 is grounded through NPN transistor Q4. There is a voltage difference Vbe between the internal supply voltage port V2 and the base of PNP transistor Q3, which causes PNP transistor Q3 to operate in the saturation region. The voltage of the internal supply voltage port V2 flows through PNP transistor Q3 to the base of NPN transistor Q5. Since the emitter of PNP transistor Q3 is grounded, the base voltage Vb of NPN transistor Q5 is much larger than the emitter voltage Ve of NPN transistor Q5, so NPN transistor Q5 also operates in the saturation region.

[0029] Working process: MCU regularly sends high and low level signals to the switch state scanning control port SW1 through the general output port GPIO1. When the general output port GPIO1 of the microcontroller MCU sends a high level to the switch state scanning control port SW1, the NPN transistor Q2 is turned on, and then drives the PNP transistor Q1 to turn on. Since the NPN transistor Q5 works in the saturation region (conduction), the output voltage of the output signal port SW3 at this time is the result of the voltage divider resistor R1 and the voltage divider resistor R2, that is, V SW3 =V1*R1 / (R1+R2), in this embodiment, the voltage divider resistor R1=voltage divider resistor R2=1K, and the car power supply voltage terminal V1=12V, so V SW3 =12*1 / 2=6V;

[0030] When the general output port GPIO1 of the microcontroller MCU sends a low level to the switch state scanning control port SW1, the NPN transistor Q2 and the PNP transistor Q1 are both cut off. Therefore, the output voltage of the output signal port SW3 is the voltage received by the short-circuit detection port SW2. At this time, the P gear switch state and the EPB switch state can be transmitted to the microcontroller MCU. The microcontroller MCU performs logical judgment on the transmission data of the digital-to-analog conversion port ADC1, the digital-to-analog conversion port ADC2, the digital-to-analog conversion port ADC3, and the digital-to-analog conversion port ADC4 within one cycle, and judges the consistency of the logical result with the action state of the EPB switch or the P gear switch, and transmits the judgment result to the vehicle controller through a hard-line signal or a CAN network signal, and uses the vehicle controller to control the actuator action.

[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A universal switch state detection circuit for an EPB switch and a P gear switch, characterized by: It includes a switch state control real-time monitoring module and an output module for real-time scanning and monitoring the interface status of the EPB switch or the P gear switch. The input end of the switch state control real-time monitoring module is connected to the EPB switch or the P gear switch. The switch state control real-time monitoring module is connected to the digital-to-analog conversion port ADC1 of the microcontroller MCU through the output module. The microcontroller MCU is connected to the vehicle controller, and the vehicle controller is connected to the actuator.

2. The universal switch state detection circuit for an EPB switch and a P gear switch according to claim 1, characterized in that: The switch state control real-time monitoring module includes a PNP transistor Q1, an NPN transistor Q2 and a voltage divider resistor R1, wherein the collector of the PNP transistor Q1 is connected to the vehicle power supply voltage terminal V1, the emitter of the PNP transistor Q1 is connected to the short-circuit detection port SW2 via the voltage divider resistor R1, the base of the PNP transistor Q1 is connected to the collector of the NPN transistor Q2, the emitter of the NPN transistor Q2 is grounded, and the base of the NPN transistor Q2 is connected to the general output port GPIO1 of the microcontroller MCU via the switch state scanning control port SW1.

3. The universal switch state detection circuit for an EPB switch and a P gear switch according to claim 2, characterized in that: The output module includes a PNP transistor Q3, an NPN transistor Q4, an NPN transistor Q5 and a voltage divider resistor R2. The base of the NPN transistor Q4 is connected to the internal driving voltage port V3, the emitter of the NPN transistor Q4 is grounded, the collector of the NPN transistor Q4 is connected to the base of the PNP transistor Q3, the collector of the PNP transistor Q3 is connected to the internal power supply voltage port V2, the emitter of the PNP transistor Q3 is connected to the base of the NPN transistor Q5, the collector of the NPN transistor Q5 is connected between the voltage divider resistor R1 and the short-circuit detection port SW2, the emitter of the NPN transistor Q5 is connected in series with the voltage divider resistor R2 and then grounded, and an output signal port SW3 is also connected between the emitter of the NPN transistor Q5 and the voltage divider resistor R2, and the output signal port SW3 is connected to the digital-to-analog conversion port ADC1 of the microcontroller MCU.

4. The universal switch state detection circuit for an EPB switch and a P gear switch according to claim 3, characterized in that: One end of a filtering energy storage capacitor C1 is further connected between the voltage dividing resistor R2 and the output signal port SW3 , and the other end of the filtering energy storage capacitor C1 is grounded.

5. The universal switch state detection circuit for an EPB switch and a P gear switch according to claim 4, characterized in that: The EPB switch is a four-wire EPB switch. The four state output ports of the four-wire EPB switch are respectively connected to the short circuit detection port SW2 of the four switch state control real-time monitoring modules via the external switch state input signal port SW4, the external switch state input signal port SW5, the external switch state input signal port SW6, and the external switch state input signal port SW7. The general output port GPIO1, the general output port GPIO2, the general output port GPIO3, and the general output port GPIO4 of the microcontroller MCU are respectively connected to the switch state scan control port SW1 of the four switch state control real-time monitoring modules. The output signal port SW3 of the four output modules is respectively connected to the digital-to-analog conversion port ADC1, the digital-to-analog conversion port ADC2, the digital-to-analog conversion port ADC3, and the digital-to-analog conversion port ADC4 of the microcontroller MCU; And the general output port GPIO1, the general output port GPIO2, the general output port GPIO3, and the general output port GPIO4 periodically output high and low levels.

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