Automobile anti-theft circuit

Abstract

The utility model discloses an automobile anti-theft circuit, which belongs to the technical field of automobile electronics and comprises a microcontroller, a first control module, a short-circuit protection module, an EMI (Electro-Magnetic Interference) protection module and an EFI (Extensible Firmware Interface) ECU (Electronic Control Unit) module, the microcontroller is respectively connected with the first control module and the short circuit protection module, the first control module is respectively connected with the short circuit protection module and the EMI protection module, and the EMI protection module is connected with the EFI ECU module; when the first control module is started, the communication on the automobile communication line is interrupted; the anti-theft circuit is arranged in the communication circuit of the automobile, when the automobile is locked, due to the existence of the anti-theft circuit, the automobile cannot communicate and cannot be ignited, and the anti-theft capacity of the automobile is greatly improved.

Description

Technical Field

[0001] The present invention belongs to the field of automobile electronic technology, and in particular relates to an automobile anti-theft circuit. Background Art

[0002] Usually the car anti-theft mode is as follows Figure 1 As shown in the figure, the IMMO ECU (engine immobilizer control unit) and the EFI ECU (electronic fuel injection control unit) are connected via a single-wire bus. The IMMO ECU stores a specific key, which establishes a communication handshake with the EFI ECU to control the switch of the engine signal and further control whether the car can start. The IMMO ECU is usually installed under the dashboard of the car and is easy to identify. If the key stored in the IMMO ECU is cracked, the car will be at risk of being stolen. Utility Model Content

[0003] This article aims to provide a car anti-theft circuit, which is set in the communication circuit of the car. When the car is locked, due to the existence of this circuit, the car cannot communicate or start, which greatly improves the anti-theft ability of the car.

[0004] The technical solutions adopted in this paper to solve the above technical problems are as follows:

[0005] According to one aspect of the present invention, a car anti-theft circuit is provided, comprising: a microcontroller, a first control module, a short-circuit protection module, an EMI protection module and an EFI ECU module; the microcontroller is connected to the first control module and the short-circuit protection module respectively, the first control module is connected to the short-circuit protection module and the EMI protection module respectively, and the EMI protection module is connected to the EFI ECU module; when the first control module is turned on, the communication on the car communication line is interrupted.

[0006] Optionally, it further includes: a second control module, wherein the second control module is connected to the microcontroller and the short-circuit protection module.

[0007] Optionally, a power switch control module is provided between the microcontroller and the first control module, and the power switch control module is also connected to a system power supply.

[0008] Optionally, the system power supply output SYS-5V is connected to the power switch control module.

[0009] Optionally, the microcontroller is the main control chip of the T-BOX, and two GPIOs of the microcontroller are connected to the second control module and the power switch control module respectively. The GPIO of the microcontroller controls the opening and closing of the second control module and the power switch control module by outputting high and low levels.

[0010] Optionally, the power switch control module includes: a MOS tube VT101, a transistor VT102, a resistor R101, a resistor R102, a resistor R103, a resistor R104, a capacitor C101, and a capacitor C102, wherein the drain of the MOS tube VT101, one end of the resistor R101, and one end of the capacitor C101 are connected to the system power supply, the gate of the MOS tube VT101 is connected to the other end of the resistor R101, the other end of the capacitor C101, and one end of the resistor R104, the source of the MOS tube VT101 is connected to one end of the capacitor C102, the other end of the capacitor C102 is grounded, the other end of the resistor R104 is connected to the collector of the transistor VT102, the base of the transistor VT102 is connected to one end of the resistor R102 and one end of the resistor R103, the emitter of the transistor VT102 and the other end of the resistor R103 are grounded together, and the other end of the resistor R102 is connected to the microcontroller.

[0011] Optionally, the first control module includes: a MOS tube VT104, a resistor R105, a resistor R106 and a capacitor C103, wherein one end of the resistor R105 is connected to the source of the MOS tube VT101, the other end of the resistor R105 is connected to one end of the resistor R106, one end of the capacitor C103 and the gate of the MOS tube VT104, and the other end of the resistor R106 and the other end of the capacitor C103 are grounded together.

[0012] Optionally, the short-circuit protection module includes: a transistor VT103, a capacitor C105, a resistor R109 and a resistor R110, wherein the collector of the transistor VT103 is connected to the gate of the MOS tube VT104, the emitter of the transistor VT103 is grounded, the base of the transistor VT103 is connected to one end of the resistor R109, the other end of the resistor R109 is connected to one end of the capacitor C105, one end of the resistor R110 and the source of the MOS tube VT104, and the other end of the capacitor C105 is grounded.

[0013] Optionally, the second control module includes: a MOS tube VT105, a resistor R107, a resistor R108 and a capacitor C104, wherein one end of the resistor R107 is connected to the microcontroller, the other end of the resistor R105 is connected to one end of the resistor R106, one end of the capacitor C103 and the gate of the MOS tube VT104, and the other end of the resistor R106 and the other end of the capacitor C103 are grounded together.

[0014] Optionally, the EMI protection module includes: a magnetic bead L101, a TVS diode VD101, a TVS diode VD102, a capacitor C106 and a capacitor C107, wherein one end of the magnetic bead L101 is connected to the drain of the MOS tube VT104, the other end of the magnetic bead L101 is connected to the EFI ECU module together with one end of the capacitor C106 and one end of the TVS diode VD101, the other end of the capacitor C106 is connected to one end of the capacitor C107, the other end of the capacitor C107 is grounded, the other end of the TVS diode VD101 is connected to one end of the TVS diode VD102, and the other end of the TVS diode VD102 is grounded.

[0015] An automobile anti-theft circuit according to an embodiment of the utility model comprises: a microcontroller, a first control module, a short-circuit protection module, an EMI protection module and an EFI ECU module; the microcontroller is respectively connected to the first control module and the short-circuit protection module, the first control module is respectively connected to the short-circuit protection module and the EMI protection module, and the EMI protection module is connected to the EFI ECU module; when the first control module is turned on, the communication on the automobile communication line is interrupted; by arranging the anti-theft circuit in the communication circuit of the automobile, when the automobile is locked, due to the existence of the circuit, the automobile cannot communicate and cannot start the engine, thereby greatly improving the anti-theft capability of the automobile. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a functional schematic diagram of a car anti-theft mode circuit in the prior art;

[0017] Figure 2 A circuit function diagram of a car anti-theft circuit provided in the first embodiment of the utility model;

[0018] Figure 3 A circuit function diagram of another automobile anti-theft circuit provided in Embodiment 1 of the utility model;

[0019] Figure 4 A circuit function diagram of another automobile anti-theft circuit provided in the first embodiment of the utility model;

[0020] Figure 5 The present invention provides a circuit diagram of a car anti-theft circuit according to the first embodiment of the present invention.

[0021] The realization of the purpose, functional features and advantages of this article will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0022] In order to make the technical problems, technical solutions and beneficial effects to be solved by this article clearer and more understandable, this article is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain this article and are not used to limit this article.

[0023] In the subsequent description, the suffixes such as "module", "component" or "unit" used to represent elements are only used to facilitate the description of the present invention, and have no specific meanings. Therefore, "module", "component" or "unit" can be used in a mixed manner.

[0024] Embodiment 1

[0025] like Figure 2 As shown, in this embodiment, an automobile anti-theft circuit includes: a microcontroller, a first control module, a short-circuit protection module, an EMI protection module and an EFI ECU module; the microcontroller is connected to the first control module and the short-circuit protection module respectively, the first control module is connected to the short-circuit protection module and the EMI protection module respectively, and the EMI protection module is connected to the EFI ECU module; when the first control module is turned on, the communication on the automobile communication line is interrupted.

[0026] In this embodiment, by setting the anti-theft circuit in the communication circuit of the car, when the car is locked, due to the existence of the circuit, the car cannot communicate or start, which greatly improves the anti-theft capability of the car.

[0027] In this embodiment, the anti-theft control circuit can be added to the vehicle-mounted telematics terminal, namely, T-BOX (Telematics BOX).

[0028] like Figure 3 As shown, in this embodiment, it also includes: a second control module, which is connected to the microcontroller and the short-circuit protection module.

[0029] like Figure 4 As shown, in this embodiment, a power switch control module is provided between the microcontroller and the first control module, and the power switch control module is also connected to the system power supply.

[0030] In this embodiment, the microcontroller 301 further controls the switch of the first control module 303 by controlling the switch of the power switch control module 302; at the same time, the microcontroller 301 controls the switch of the second control module 305; when the first control module 303 and the second control module 305 are turned on at the same time, the communication bus of the EFI ECU can be connected to GND, so that the EFI ECU and the IMMO ECU will not establish a communication connection, which plays an anti-theft protection role. When the car is in normal use, it is only necessary to disconnect the first control module 302 and the second control module 305, which will not affect the normal communication of the bus. At the same time, due to the complex environment of the car, it is easy to cause interference and short circuit of the wiring harness. This embodiment has the function of preventing interference and short circuit protection. This embodiment uses two control modules, and the EMI protection module uses two TVS in series. The two capacitors are used in series to improve the reliability of the entire circuit, prevent stress damage or electrical damage to one of the components, and cause the EFI ECU communication bus to be directly connected to GND, causing the car to fail to start normally.

[0031] In this embodiment, the microcontroller is the main control chip of the T-BOX, and two GPIOs of the microcontroller are connected to the second control module and the power switch control module respectively. The GPIO of the microcontroller controls the opening and closing of the second control module and the power switch control module by outputting high and low levels.

[0032] like Figure 5 As shown, in this embodiment, the power switch control module includes: a MOS tube VT101, a transistor VT102, a resistor R101, a resistor R102, a resistor R103, a resistor R104, a capacitor C101, and a capacitor C102, wherein the drain of the MOS tube VT101, one end of the resistor R101, and one end of the capacitor C101 are connected to the system power supply, the gate of the MOS tube VT101 is connected to the other end of the resistor R101, the other end of the capacitor C101, and one end of the resistor R104, the source of the MOS tube VT101 is connected to one end of the capacitor C102, the other end of the capacitor C102 is grounded, the other end of the resistor R104 is connected to the collector of the transistor VT102, the base of the transistor VT102 is connected to one end of the resistor R102 and one end of the resistor R103, the emitter of the transistor VT102 and the other end of the resistor R103 are grounded together, and the other end of the resistor R102 is connected to the microcontroller.

[0033] In this embodiment, MCU controls the on and off of NPN transistor VT102. When MCU outputs a high level, transistor VT102 is on, and when MCU outputs a low level, transistor VT102 is off. Resistor R102 plays a role in protecting the base of the transistor, and resistor R103 fixes the initial state of the transistor. When transistor VT102 is turned on, PMOSFET VT101 can be turned on; wherein resistor R101, resistor R104 and capacitor C101 play a role in slow start, and capacitor C102 filters out interference.

[0034] In this embodiment, the first control module includes: a MOS tube VT104, a resistor R105, a resistor R106 and a capacitor C103, wherein one end of the resistor R105 is connected to the source of the MOS tube VT101, the other end of the resistor R105 is connected to one end of the resistor R106, one end of the capacitor C103 and the gate of the MOS tube VT104, and the other end of the resistor R106 and the other end of the capacitor C103 are grounded together.

[0035] In this embodiment, the power switch control module 302 controls the on and off of the NMOSFET VT104. When the power switch control module is turned on, it outputs a high level, and at this time, the NMOSFET VT104 is controlled to be turned on; the resistors R105, R106 and the capacitor C103 play a protective and filtering role in this circuit.

[0036] In this embodiment, the system power supply output SYS-5V is connected to the power switch control module. The SYS-5V power supply is used to control the opening of the NMOSFET VT104 in the first control module in order to increase the voltage Vgs between the gate and the source of the NMOSFET to prevent the possible high source voltage of VT104 from causing the voltage Vgs between the gate and the source to fail to meet the opening voltage threshold Vgs(th).

[0037] In this embodiment, the short-circuit protection module includes: a transistor VT103, a capacitor C105, a resistor R109 and a resistor R110, wherein the collector of the transistor VT103 is connected to the gate of the MOS tube VT104, the emitter of the transistor VT103 is grounded, the base of the transistor VT103 is connected to one end of the resistor R109, the other end of the resistor R109 is connected to one end of the capacitor C105, one end of the resistor R110 and the source of the MOS tube VT104, and the other end of the capacitor C105 is grounded.

[0038] In this embodiment, the NPN transistor VT103 and the resistor R110 together constitute short-circuit protection, which mainly plays a current limiting role, that is, limiting the path current to 0.7V / R110, thereby playing a protective role, wherein 0.7V is the conduction voltage of the transistor VT103, and the appropriate resistance value of R110 is selected according to the needs. The R110 resistor needs to meet the requirement that the upper voltage division of this circuit will not cause the NPN transistor VT103 to conduct when the circuit is working normally, and when short-circuited, the current is limited to not exceed the maximum current of all components in the path. Capacitor C105 has a filtering function.

[0039] In this embodiment, the second control module includes: a MOS tube VT105, a resistor R107, a resistor R108 and a capacitor C104, wherein one end of the resistor R107 is connected to the microcontroller, the other end of the resistor R105 is connected to one end of the resistor R106, one end of the capacitor C103 and the gate of the MOS tube VT104, and the other end of the resistor R106 and the other end of the capacitor C103 are grounded together.

[0040] In this embodiment, the MCU controls the on and off of the NMOSFET VT105. When the MCU outputs a high level, the NMOSFET VT105 is turned on, and when turned on, the short circuit protection module 304 is connected to GND. The resistor R107, the resistor R108 and the capacitor C104 play a protective filtering role in this circuit.

[0041] In this embodiment, the EMI protection module includes: a magnetic bead L101, a TVS diode VD101, a TVS diode VD102, a capacitor C106 and a capacitor C107, wherein one end of the magnetic bead L101 is connected to the drain of the MOS tube VT104, the other end of the magnetic bead L101 is connected to the EFI ECU module together with one end of the capacitor C106 and one end of the TVS diode VD101, the other end of the capacitor C106 is connected to one end of the capacitor C107, the other end of the capacitor C107 is grounded, the other end of the TVS diode VD101 is connected to one end of the TVS diode VD102, and the other end of the TVS diode VD102 is grounded.

[0042] In this embodiment, TVS diodes VD101 and VD102 and capacitors C106 and C107 are used for electrostatic protection and surge protection, and magnetic beads L101 play a role in decoupling and filtering interference.

[0043] In this embodiment, the EFI ECU module 307 can control the start of the car, and the communication bus connected to the IMMO ECU inside the EFI ECU module 307 is usually pulled up to the car power supply +B by a resistor.

[0044] like Figure 5As shown, the car power supply +B is 8V~16V, the pull-up resistor R is usually (1.5~2.2)KΩ, the communication bus level is (8~16)V, which is recognized as high, and the communication bus level is not more than 1.5V, which is recognized as low.

[0045] The preferred embodiments of the present invention are described above with reference to the accompanying drawings, but the scope of the present invention is not limited by this. Any modification, equivalent substitution and improvement made by a person skilled in the art without departing from the scope and essence of the present invention shall be within the scope of the present invention.

Claims

1. A car anti-theft circuit, It is characterized in that include: A microcontroller, a first control module, a short-circuit protection module, an EMI protection module and an EFI ECU module; the microcontroller is connected to the first control module and the short-circuit protection module respectively, the first control module is connected to the short-circuit protection module and the EMI protection module respectively, and the EMI protection module is connected to the EFI ECU module; when the first control module is turned on, the communication on the vehicle communication line is interrupted.

2. A car anti-theft circuit according to claim 1, It is characterized in that Also includes: A second control module is connected to the microcontroller and the short-circuit protection module.

3. A car anti-theft circuit according to claim 2, It is characterized in that A power switch control module is provided between the microcontroller and the first control module, and the power switch control module is also connected to the system power supply.

4. A car anti-theft circuit according to claim 3, It is characterized in that The system power supply output SYS-5V is connected to the power switch control module.

5. A car anti-theft circuit according to claim 3, It is characterized in that The microcontroller is the main control chip of the T-BOX. Two GPIOs of the microcontroller are respectively connected to the second control module and the power switch control module. The GPIO of the microcontroller controls the opening and closing of the second control module and the power switch control module by outputting high and low levels.

6. A car anti-theft circuit according to claim 3, It is characterized in that The power switch control module includes: a MOS tube VT101, a transistor VT102, a resistor R101, a resistor R102, a resistor R103, a resistor R104, a capacitor C101, and a capacitor C102, wherein the drain of the MOS tube VT101, one end of the resistor R101, and one end of the capacitor C101 are connected to the system power supply, the gate of the MOS tube VT101 is connected to the other end of the resistor R101, the other end of the capacitor C101, and one end of the resistor R104, the source of the MOS tube VT101 is connected to one end of the capacitor C102, the other end of the capacitor C102 is grounded, the other end of the resistor R104 is connected to the collector of the transistor VT102, the base of the transistor VT102 is connected to one end of the resistor R102 and one end of the resistor R103, the emitter of the transistor VT102 and the other end of the resistor R103 are grounded together, and the other end of the resistor R102 is connected to the microcontroller.

7. A car anti-theft circuit according to claim 6, It is characterized in that The first control module includes: a MOS tube VT104, a resistor R105, a resistor R106 and a capacitor C103, wherein one end of the resistor R105 is connected to the source of the MOS tube VT101, the other end of the resistor R105 is connected to one end of the resistor R106, one end of the capacitor C103 and the gate of the MOS tube VT104, and the other end of the resistor R106 and the other end of the capacitor C103 are grounded together.

8. A car anti-theft circuit according to claim 7, It is characterized in that The short-circuit protection module includes: a transistor VT103, a capacitor C105, a resistor R109 and a resistor R110, wherein the collector of the transistor VT103 is connected to the gate of the MOS tube VT104, the emitter of the transistor VT103 is grounded, the base of the transistor VT103 is connected to one end of the resistor R109, the other end of the resistor R109 is connected to one end of the capacitor C105, one end of the resistor R110 and the source of the MOS tube VT104, and the other end of the capacitor C105 is grounded.

9. A car anti-theft circuit according to claim 8, It is characterized in that The second control module includes: a MOS tube VT105, a resistor R107, a resistor R108 and a capacitor C104, wherein one end of the resistor R107 is connected to the microcontroller, the other end of the resistor R105 is connected to one end of the resistor R106, one end of the capacitor C103 and the gate of the MOS tube VT104, and the other end of the resistor R106 and the other end of the capacitor C103 are grounded together.

10. The automobile anti-theft circuit according to claim 7, It is characterized in that The EMI protection module includes: a magnetic bead L101, a TVS diode VD101, a TVS diode VD102, a capacitor C106 and a capacitor C107, wherein one end of the magnetic bead L101 is connected to the drain of the MOS tube VT104, the other end of the magnetic bead L101 is connected to the EFI ECU module together with one end of the capacitor C106 and one end of the TVS diode VD101, the other end of the capacitor C106 is connected to one end of the capacitor C107, the other end of the capacitor C107 is grounded, the other end of the TVS diode VD101 is connected to one end of the TVS diode VD102, and the other end of the TVS diode VD102 is grounded.

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