Circuit for detecting passenger car hard wire switch signal

Abstract

The utility model discloses a circuit for detecting a passenger car hard wire switch signal. The composite triode Q3 is formed by connecting two triodes, an emitting electrode of the first triode is grounded, a base electrode of the first triode is connected with a GPIO general input port DRVTESTSW of the MCU micro-control unit, a collecting electrode of the first triode is connected with a base electrode of the second triode, an emitting electrode of the second triode is connected to working voltage, and a collecting electrode of the second triode is grounded through a diode D2, a resistor R11, a resistor R12 and a resistor R13 in sequence; an ADC mode conversion port ADSWSINGAL connected to the MCU micro-control unit is led out between the resistor R11 and the resistor R12, and an external hard wire switch signal SWSINGAL connected to the passenger car is led out between the resistor R12 and the resistor R13. According to the utility model, the full-coverage identification of three logics of the switch is realized, the identification voltage values of three states are stable and do not change along with the change of the voltage of a vehicle-mounted storage battery, and the operation intention of a user can be identified more accurately.

Description

Technical Field

[0001] The utility model relates to the technical field of switch detection, in particular to a circuit for detecting hard-line switch signals of a passenger car. Background Art

[0002] Users use external physical switches to activate and deactivate certain specific functions of passenger cars. The activation and deactivation of certain functions involve the safe driving of the vehicle, so correctly identifying the external switch action is an important part of ensuring the functional safety design of the controller.

[0003] Usually, in the circuit design of external switches, the driving source comes from the vehicle battery, and the voltage divider resistor is generally selected according to the specific switch identification logic for parameter matching. This method has the following two problems:

[0004] 1. Parameter matching based on specific switch identification logic can only identify two logical states, such as floating when the function is not turned on and connected to the power supply when it is turned on. However, the grounding fault mode cannot be identified at this time.

[0005] 2. The driving source comes from the vehicle battery. Considering the instability of the battery voltage, there is a risk of misidentifying the switch action under some special working conditions. Utility Model Content

[0006] In order to solve the problems existing in the background technology, the utility model discloses a circuit for detecting a hard-wire switch signal of a passenger car.

[0007] The technical solution of the utility model is achieved in this way:

[0008] The circuit of the utility model comprises a composite triode Q3, resistors R11-R13, diodes D2-diode D3 and capacitor C7; the composite triode Q3 is directly connected to the GPIO general input port DRV_TEST_SW of the MCU micro control unit, and the composite triode Q3 is respectively connected to the ADC mode conversion port AD_SW_SINGAL of the MCU micro control unit and the external hard-line switch signal SW_SINGAL of the passenger car via the resistors R11-R13, diodes D2-diode D3 and capacitor C7.

[0009] The composite transistor Q3 is mainly composed of two transistors connected in reverse arrangement, wherein the emitter of the first transistor is grounded, the base of the first transistor is connected to the GPIO general input port DRV_TEST_SW of the MCU micro control unit, the collector of the first transistor is connected to the base of the second transistor, the emitter of the second transistor is connected to the working voltage, and the collector of the second transistor is grounded via the diode D2, the resistor R11, the resistor R12, and the resistor R13 in sequence; wherein, an ADC mode conversion port AD_SW_SINGAL connected to the MCU micro control unit is led out between the resistor R11 and the resistor R12, and an external hard-line switch signal SW_SINGAL connected to the passenger car is led out between the resistor R12 and the resistor R13.

[0010] The ADC mode conversion port AD_SW_SINGAL of the MCU micro control unit is connected to the ground and the working voltage via the capacitor C7 and the diode D3 respectively.

[0011] The anode of the diode D2 is connected to the composite transistor Q3, and the cathode is connected to the resistor R11.

[0012] The anode of the diode D3 is connected to the ADC mode conversion port AD_SW_SINGAL, and the cathode is connected to the working voltage.

[0013] Beneficial effects of the utility model:

[0014] The circuit of the utility model can be used to identify three states of external hard-wired switch signals: grounding, suspension, and power supply through the MCU microcontroller unit for different voltages, thereby achieving full coverage recognition of the three logics of the switch hardware and the recognition voltage values ​​of the three states are stable and will not change with the change of the vehicle battery voltage, and can more accurately recognize the user's operating intentions. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The schematic diagram of a circuit for detecting hard-wire switch signals in passenger cars is shown in FIG. DETAILED DESCRIPTION

[0016] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0017] like Figure 1 As shown, it includes an MCU microcontroller unit, a composite transistor Q3, resistors R11 to R13, diodes D2 to D3 and a capacitor C7; the composite transistor Q3 is directly connected to the GPIO general input port DRV_TEST_SW of the MCU microcontroller unit, and the composite transistor Q3 is respectively connected to the ADC mode conversion port AD_SW_SINGAL of the MCU microcontroller unit and the external hard-line switch signal SW_SINGAL of the passenger car through resistors R11 to R13, diodes D2 to D3 and capacitor C7.

[0018] like Figure 1 As shown, the composite transistor Q3 is mainly composed of two transistors connected in reverse arrangement, wherein the emitter pin 1 of the first transistor is grounded, the base pin 2 of the first transistor is connected to the GPIO general input port DRV_TEST_SW of the MCU microcontroller unit, the collector pin 6 of the first transistor is connected to the base pin 5 of the second transistor, the emitter pin 4 of the second transistor is connected to the working voltage 3V3, and the collector pin 3 of the second transistor is grounded via the diode D2, the resistor R11, the resistor R12, and the resistor R13 in sequence;

[0019] Among them, the ADC mode conversion port AD_SW_SINGAL connected to the MCU micro control unit is led out between the resistor R11 and the resistor R12, and the external hard-line switch signal SW_SINGAL connected to the passenger car is led out between the resistor R12 and the resistor R13.

[0020] The ADC mode conversion port AD_SW_SINGAL of the MCU microcontroller unit is also connected to ground via capacitor C7 and diode D3, and the working voltage is 3V3.

[0021] The anode of diode D2 is connected to the composite transistor Q3, and the cathode is connected to the resistor R11.

[0022] The anode of diode D3 is connected to the ADC mode conversion port AD_SW_SINGAL, and the cathode is connected to the working voltage.

[0023] In the specific implementation, the model of the composite transistor Q3 is PUMD16-Q, the model of the diode D2 is: S-LBAS21HT1G, the resistance value of the resistor R11 is 300K, the resistance value of the resistor R12 is 30K, the resistance value of the resistor R13 is 300K, the capacitance value of the capacitor C7 is 100nF, and the model of the diode D3 is: S-LBAS21HT1G.

[0024] In the specific implementation, the following three logic states of external hard lines are described:

[0025] 1. The external hard-wire signal input is suspended;

[0026] The voltage read by the ADC mode conversion port AD_SW_SINGAL of the MCU microcontroller unit is the intermediate voltage between the working voltage and the ground after the voltage drop through the diode D2, the resistor R11, the resistor R12, and the resistor R13. The collector pin 3 of the second transistor of the composite transistor Q3 has a voltage drop of 0.7V through the diode D2. The composite transistor Q3 is followed by a voltage divider circuit of three resistors: resistor R11, resistor R12, and resistor R13.

[0027] The voltage read by the ADC mode conversion port AD_SW_SINGAL of the MCU microcontroller unit is:

[0028] (VDD-VD2)*(R12+R13) / (R11+R12+R13)=(3.3V-0.7V)*(330K) / (630K)=1.362V

[0029] Among them, VDD represents the output working voltage of the GPIO general input port DRV_TEST_SW of the MCU microcontroller unit, and VD2 represents the voltage drop of the diode D2.

[0030] 2. External hard-wire signal input is grounded;

[0031] The voltage read by the ADC mode conversion port AD_SW_SINGAL of the MCU microcontroller unit is the intermediate voltage between the working voltage and the external hard-line switch signal SW_SINGAL after the voltage drop through the diode D2, the resistor R11, and the resistor R12.

[0032] The collector pin 3 of the second transistor of the composite transistor Q3 has a voltage drop of 0.7 V through the diode D2. Since the external hard-wired switch signal SW_SINGAL of the passenger car is grounded, the voltage is 0 V, so the resistor R13 is short-circuited, and the composite transistor Q3 is followed by a voltage divider circuit of two resistors: resistor R11 and resistor R12.

[0033] The voltage read by the ADC mode conversion port AD_SW_SINGAL of the MCU microcontroller unit is:

[0034] (VDD-VD2)*(R12) / (R11+R12)=(3.3V-0.7V)*(30K) / (330K)=0.236V

[0035] 3. External hard-wire signal input is connected to power supply (+12V);

[0036] The voltage read by the ADC mode conversion port AD_SW_SINGAL of the MCU microcontroller unit is the intermediate voltage between the working voltage and the external hard-line switch signal SW_SINGAL via the diode D2, the resistor R11, and the resistor R12.

[0037] The collector pin 3 voltage of the second transistor of the composite transistor Q3 is the working voltage 3.3V. Because the external hard-wire switch signal SW_SINGAL of the passenger car is connected to the power supply, the voltage is +12V, which is much greater than 3V, so the diode D2 will not be turned on. Therefore, the circuit loop is the external hard-wire switch signal SW_SINGAL passing through the resistor R12 and then through the transistor D3 to the 3V3 working voltage. At this time, the transistor D3 is turned on, so that the voltage at the ADC mode conversion port AD_SW_SINGAL will be clamped.

[0038] The voltage read by the ADC mode conversion port AD_SW_SINGAL of the MCU microcontroller unit is:

[0039] VDD-VD3=3.3+0.7=4V

[0040] Wherein, VD3 represents the voltage drop of the diode D3.

[0041] Therefore, in the specific implementation of the detection, the voltage U is read by the ADC mode conversion port AD_SW_SINGAL of the MCU microcontroller unit, and the following judgment is performed to obtain the status result of the external hard-wire switch signal SW_SINGAL of the passenger car:

[0042] If the voltage U read is U=(VDD-VD2)*(R12+R13) / (R11+R12+R13)=1.362V, the external hard-wire switch signal SW_SINGAL of the passenger car is in a suspended state;

[0043] If the voltage U read is U=(VDD-VD2)*(R12) / (R11+R12)=0.236V, the external hard-wire switch signal SW_SINGAL of the passenger car is grounded;

[0044] If the read voltage U is U=VDD-VD3=4V, the state of the external hard-wire switch signal SW_SINGAL of the passenger car is connected to the power supply.

[0045] In specific implementation, within the normal operating voltage range of 9V-16V for passenger cars, since 3.3V and the diode voltage drop of 0.7V are stable, the AD_SW_SINGAL port voltage corresponding to the three logics of the switch is a fixed value and does not change with changes in external voltage.

[0046] Therefore, the MCU controller uses the above three different logic states and corresponding relatively fixed voltages to distinguish the logic of the external hard line and realize detection and identification processing.

Claims

1. A circuit for detecting hard-wire switch signals of a passenger car, characterized in that: It includes a composite transistor Q3, resistors R11-R13, diodes D2-diode D3 and capacitor C7; the composite transistor Q3 is directly connected to the GPIO general input port DRV_TEST_SW of the MCU micro control unit, and the composite transistor Q3 is respectively connected to the ADC mode conversion port AD_SW_SINGAL of the MCU micro control unit and the external hard-line switch signal SW_SINGAL of the passenger car through resistors R11-R13, diodes D2-diode D3 and capacitor C7.

2. A circuit for detecting a hard-wire switch signal of a passenger car according to claim 1, characterized in that: The composite triode Q3 is mainly composed of two triodes connected in reverse arrangement.

3. A circuit for detecting a hard-wire switch signal of a passenger car according to claim 2, characterized in that: In the composite transistor Q3, the emitter of the first transistor is grounded, the base of the first transistor is connected to the GPIO general input port DRV_TEST_SW of the MCU micro control unit, the collector of the first transistor is connected to the base of the second transistor, the emitter of the second transistor is connected to the working voltage, and the collector of the second transistor is grounded via the diode D2, the resistor R11, the resistor R12, and the resistor R13 in sequence; wherein, an ADC mode conversion port AD_SW_SINGAL connected to the MCU micro control unit is led out between the resistor R11 and the resistor R12, and an external hard-wired switch signal SW_SINGAL connected to the passenger car is led out between the resistor R12 and the resistor R13.

4. A circuit for detecting a hard-wire switch signal of a passenger car according to claim 2, characterized in that: The ADC mode conversion port AD_SW_SINGAL of the MCU micro control unit is connected to the ground and the working voltage via the capacitor C7 and the diode D3 respectively.

5. A circuit for detecting a hard-wire switch signal of a passenger car according to claim 2, characterized in that: The anode of the diode D2 is connected to the composite transistor Q3, and the cathode is connected to the resistor R11.

6. A circuit for detecting a hard-wire switch signal of a passenger car according to claim 3, characterized in that: The anode of the diode D3 is connected to the ADC mode conversion port AD_SW_SINGAL, and the cathode is connected to the working voltage.

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