K line communication circuit for electric vehicle

Abstract

The utility model discloses a K-line communication circuit for an electric vehicle, which relates to the technical field of communication circuits, and comprises an overvoltage and undervoltage protection module, a signal receiving module and a signal transmitting module which are adaptively connected with a K bus, the overvoltage and undervoltage protection module is used for providing overvoltage and undervoltage protection for the K bus, and the signal receiving module is used for receiving the signal and transmitting the signal to the signal transmitting module. The overvoltage and undervoltage protection module comprises a fuse F1 and a TVS tube D5, the fuse F1 is connected in series in a K bus, the negative electrode of the TVS tube D5 is connected with one end of the fuse F1, and the positive electrode of the TVS tube D5 is grounded; the signal receiving module comprises a signal receiving end, the signal sending module comprises a signal sending end, the signal receiving end is used for receiving an input signal, and the signal sending end is used for outputting an output signal corresponding to the input signal. The K-line communication circuit has the overvoltage and undervoltage protection capability, and has the advantages of strong anti-interference capability, high reliability and high stability.

Description

TECHNICAL FIELD

[0001] The utility model relates to communication circuit technical field especially a K line communication circuit for electric motor car. BACKGROUND

[0002] With the acceleration of urbanization process and the improvement of people's environmental protection consciousness, two-wheeled electric vehicles can well solve the short-distance traffic congestion and energy-saving emission reduction use demand, thereby being widely applied. Under the intelligent development, the ordinary point-to-point control has been unable to meet the interaction of the whole vehicle data, therefore K line communication is widely introduced, K line (Keyword Protocol) communication is a low-cost, low-speed main line type communication mode, which can meet the real-time data interaction between components. However, since it is a single line type communication bus, it is more susceptible to environmental interference, and is easy to be permanently disabled due to overvoltage or overcurrent, or to be disabled for a short time due to pulse voltage interference, thereby causing the whole vehicle communication to be paralyzed, causing failure, reducing the user's recognition of the product, and damaging the brand image of the product. SUMMARY

[0003] The applicant proposes a K line communication circuit for electric motor car aiming at the above problems and technical needs. The technical scheme of the utility model is as follows:

[0004] A K line communication circuit for electric motor car, comprising an overvoltage and undervoltage protection module, a signal receiving module and a signal sending module connected with the K bus, wherein,

[0005] The overvoltage and undervoltage protection module is used to provide overvoltage and undervoltage protection for the K bus, and the overvoltage and undervoltage protection module comprises a fuse F1 and a TVS tube D5, the fuse F1 is connected in series in the K bus, the negative electrode of the TVS tube D5 is connected with one end of the fuse F1, and the positive electrode of the TVS tube D5 is grounded.

[0006] The signal receiving module comprises a signal receiving end, and the signal sending module comprises a signal sending end, the signal receiving end is used to receive an input signal, and the signal sending end is used to output an output signal corresponding to the input signal.

[0007] Further technical scheme, the signal receiving module comprises a switch tube Q3, a switch tube Q7, a resistor R3, a resistor R11, a resistor R14 and a resistor R20, wherein,

[0008] The signal receiving end is connected with one end of the resistor R3 and the second electrode of the switch tube Q3 through the resistor R11, the first electrode of the switch tube Q3 is connected with the other end of the resistor R3 and is connected to the first power voltage, the third electrode of the switch tube Q3 is connected with the second electrode of the switch tube Q7 through the resistor R14 and one end of the resistor R20, the other end of the resistor R20 is grounded, and the third electrode of the switch tube Q7 is connected with the K bus.

[0009] Further, the signal receiving module further comprises an overcurrent protection unit, the overcurrent protection unit comprises a switch tube Q8, a resistor R26 and a resistor R47, wherein,

[0010] The first electrode of the switch tube Q8 is grounded, the second electrode of the switch tube Q8 is connected with the first electrode of the switch tube Q7 and one end of the resistor R47 through the resistor R26, the other end of the resistor R47 is grounded, and the third electrode of the switch tube Q8 is connected with the second electrode of the switch tube Q7.

[0011] Further, the K bus is connected with the cathode of a diode D3 through the resistor R12, and the anode of the diode D3 is connected to the second power voltage.

[0012] Further, the signal sending module comprises a switch tube Q1, a switch tube Q2, a resistor R13, a resistor R19, a resistor R21, a resistor R42, a resistor R49 and a resistor R50, wherein,

[0013] One end of the resistor R21 is connected with the K bus, the other end of the resistor R21 is connected with one end of the resistor R42 and the second electrode of the switch tube Q1, and the other end of the resistor R42 and the first electrode of the switch tube Q1 are grounded;

[0014] The third electrode of the switch tube Q1 is connected with the resistor R13 and one end of the resistor R19, the other end of the resistor R13 is connected to the first power voltage, the other end of the resistor R19 is connected with the second electrode of the switch tube Q2, the third electrode of the switch tube Q2 is connected with one end of the resistor R49 and the resistor R50, the other end of the resistor R49 is connected to the first power voltage, the other end of the resistor R50 is connected with the signal sending end, and the first electrode of the switch tube Q2 is grounded.

[0015] Further, the first power voltage is 3.3V, and the second power voltage is 12V.

[0016] Further, the signal sending module further comprises an acceleration unit, the acceleration unit comprises a resistor R18 and a capacitor C16, one end of the resistor R18 is connected with one end of a resistor R21, the other end of the resistor R18 is connected with the second electrode of a switch tube Q1 and the other end of the resistor R21 through the capacitor C16.

[0017] Further, the switch tube Q1, the switch tube Q2, the switch tube Q3, the switch tube Q7 and the switch tube Q8 are triodes.

[0018] Further, the signal sending module further comprises a voltage stabilizing diode D7, the negative electrode of the voltage stabilizing diode D7 is connected with one end of the resistor R21, one end of a resistor R42 and the second electrode of the switch tube Q1, and the positive electrode of the voltage stabilizing diode D7 is grounded.

[0019] Further, the fuse F1 is a recoverable fuse.

[0020] The utility model discloses a beneficial technical effect is:

[0021] The K line communication circuit provided by the utility model is provided with an overvoltage and undervoltage protection module, and an overcurrent protection unit is arranged in the signal receiving module, so that the overvoltage and undervoltage protection and the overcurrent protection can be provided for the K bus, the problem of permanent failure of the K bus caused by overvoltage and overcurrent is solved, the problem of temporary failure of the K bus caused by pulse voltage interference is solved, the anti-interference ability of the communication circuit is enhanced, and the reliability and stability of the communication circuit are improved. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a circuit principle diagram of one embodiment of the K line communication circuit for the electric vehicle provided by the utility model.

[0023] Figure 2 is a schematic diagram of one embodiment of the K line communication architecture of the electric vehicle provided by the utility model. DETAILED DESCRIPTION

[0024] The specific embodiment of the utility model is further explained below in combination with the drawings.

[0025] The utility model provides a kind of K line communication circuit for electric vehicle, including with K bus adaptation connection overvoltage and undervoltage protection module, signal receiving module and signal sending module, wherein,

[0026] The overvoltage and undervoltage protection module is used for providing overvoltage and undervoltage protection for the K bus, and comprises a fuse F1 and a TVS (Transient Voltage Suppressor) tube D5, the fuse F1 is connected in series in the K bus, the negative electrode of the TVS tube D5 is connected with one end of the fuse F1, and the positive electrode of the TVS tube D5 is grounded.

[0027] The signal receiving module comprises a signal receiving end, and the signal sending module comprises a signal sending end, the signal receiving end is used for receiving an input signal, and the signal sending end is used for outputting an output signal corresponding to the input signal.

[0028] Specifically, the K bus is connected with the cathode of a diode D3 through a resistor R12, the anode of the diode D3 is connected with a second power supply voltage. In the embodiment, the second power supply voltage is 12V. When the K bus is in a data-free state, i.e. no data transmission is performed, the K bus voltage is pulled up and maintained at 12V through the resistor R12 and the diode D3. The TVS tube D5 is selected from a TVS tube with a breakdown voltage of 12V, when the K bus voltage exceeds 12V, the TVS tube D5 is broken down to a low resistance state, and the K bus voltage is clamped at 12V while the current is increased, when the K bus voltage is greater than 12V for a long time, i.e. overvoltage exists for a long time, the K bus current continuously increases, the fuse F1 functions to directly cut off the K bus path to protect the K bus. The fuse F1 is a recoverable fuse, which can automatically recover to a low resistance state after the K bus overcurrent and overvoltage fault is eliminated, and can be repeatedly used, thereby reducing the maintenance cost. When the K bus voltage is negative, the TVS tube D5 is positively biased to clamp the K bus voltage at -0.7V. By setting the fuse F1 and the TVS tube D5, overvoltage and undervoltage protection of the K bus can be achieved, and the interference of pulse voltage can be suppressed, thereby enhancing the anti-interference ability of the communication circuit and improving the reliability and stability of the communication circuit. The specific structure and working principle of the signal receiving module and the signal sending module can be referred to the following description.

[0029] Further, the signal receiving module comprises a switch tube Q3, a switch tube Q7, a resistor R3, a resistor R11, a resistor R14, and a resistor R20, wherein the signal receiving end is connected with one end of the resistor R3 and the second electrode of the switch tube Q3 through the resistor R11, the first electrode of the switch tube Q3 is connected with the other end of the resistor R3 and connected with a first power supply voltage, the third electrode of the switch tube Q3 is connected with one end of the resistor R20 and the second electrode of the switch tube Q7 through the resistor R14, the other end of the resistor R20 is grounded, and the third electrode of the switch tube Q7 is connected with the K bus.

[0030] Specifically, the signal receiving module further comprises an overcurrent protection unit for providing overcurrent protection, the overcurrent protection unit comprising a switch tube Q8, a resistor R26 and a resistor R47, wherein a first electrode of the switch tube Q8 is grounded, a second electrode of the switch tube Q8 is connected with a first electrode of the switch tube Q7 and one end of the resistor R47 through the resistor R26, the other end of the resistor R47 is grounded, and a third electrode of the switch tube Q8 is connected with a second electrode of the switch tube Q7.

[0031] In the embodiment, the switch tube Q3 is a PNP type triode, and the switch tube Q7 and the switch tube Q8 are NPN type triodes. For the triodes, the first electrode is the emitter, the second electrode is the base, and the third electrode is the collector. Meanwhile, the first power voltage is 3.3 V. The signal receiving module receives an input signal through a signal receiving end, and the input signal is represented by a K-TX signal. In specific implementation, the switch tube Q3, the switch tube Q7 and the switch tube Q8 can be selected from other power devices.

[0032] When the K-TX signal is a low-level signal, the base of the switch tube Q3 is at a low level, and the voltage difference between the base and the emitter of the switch tube Q3 is greater than the on-voltage of the switch tube Q3, so that the switch tube Q3 is turned on. The 3.3 V voltage is divided by the resistor R14 and the resistor R20 and then loaded to the switch tube Q7, and the voltage difference between the base and the emitter of the switch tube Q7 is greater than the on-voltage of the switch tube Q7, so that the switch tube Q7 is turned on. The switch tube Q7 pulls down the K bus voltage to 0 V through the resistor R47, i.e., the K bus voltage is at a low level. Conversely, when the K-TX signal is a high-level signal, the base of the switch tube Q3 is at a high level, and the voltage difference between the base and the emitter of the switch tube Q3 is less than the on-voltage of the switch tube Q3, so that the switch tube Q3 is turned off. At this time, the voltage difference between the base and the emitter of the switch tube Q7 is also less than the on-voltage of the switch tube Q7, so that the switch tube Q7 is turned off, and the K bus voltage is maintained at 12 V, i.e., the K bus voltage is at a high level. That is, when communication is performed, the high and low levels of the K bus voltage correspond to the high and low levels of the K-TX signal input by the signal input end.

[0033] When the switch tube Q7 is turned on and the current flowing through the switch tube Q7 is too large, the current flows through the resistor R26 and the resistor R47 to generate a voltage drop, so that the voltage difference between the base and the emitter of the switch tube Q8 is greater than the on-voltage of the switch tube Q8, the switch tube Q8 is turned on, the base potential of the switch tube Q7 is pulled down to the ground potential, and the switch tube Q7 is turned off, thereby realizing overcurrent protection and preventing the switch tube Q7, the K bus and subsequent circuits from being damaged.

[0034] Further, the signal sending module comprises a switch tube Q1, a switch tube Q2, a resistor R13, a resistor R19, a resistor R21, a resistor R42, a resistor R49 and a resistor R50, wherein one end of the resistor R21 is connected with the K bus, the other end of the resistor R21 is connected with one end of the resistor R42 and the second electrode of the switch tube Q1, the other end of the resistor R42 and the first electrode of the switch tube Q1 are grounded;

[0035] The third electrode of the switch tube Q1 is connected with one end of the resistor R13 and the resistor R19, the other end of the resistor R13 is connected with the first power supply voltage, the other end of the resistor R19 is connected with the second electrode of the switch tube Q2, the third electrode of the switch tube Q2 is connected with one end of the resistor R49 and the resistor R50, the other end of the resistor R49 is connected with the first power supply voltage, the other end of the resistor R50 is connected with the signal sending end, and the first electrode of the switch tube Q2 is grounded.

[0036] Specifically, the switch tube Q1 and the switch tube Q2 are NPN type triodes, and the definitions of the first electrode, the second electrode and the third electrode of the switch tube Q1 and the switch tube Q2 are the same as the definitions of the first electrode, the second electrode and the third electrode of the triode, which will not be repeated here.

[0037] The signal sending end in the signal sending module is used for outputting an output signal, and the output signal is represented as K-RX signal. When the K bus voltage is high, the high voltage is divided by the resistor R21 and the resistor R42 and then loaded to the base of the switch tube Q1, the voltage of the base of the switch tube Q1 is raised, the voltage difference between the base and the emitter of the switch tube Q1 is greater than the on voltage of the switch tube Q1, the switch tube Q1 is turned on, the voltage of the base of the switch tube Q2 is pulled down to the ground potential, the voltage difference between the base and the emitter of the switch tube Q2 is less than the on voltage of the switch tube Q2, the switch tube Q2 is turned off, the 3.3V voltage is divided by the resistor R49 and the resistor R50 and then output to the signal sending end, and the signal sending end outputs the K-RX signal with high level. Conversely, when the K bus voltage is low, the voltage difference between the base and the emitter of the switch tube Q1 is less than the on voltage of the switch tube Q1, the switch tube Q1 is turned off, the 3.3V voltage is divided by the resistor R13 and the resistor R19 and then loaded to the base of the switch tube Q2, the voltage difference between the base and the emitter of the switch tube Q2 is greater than the on voltage of the switch tube Q2, the switch tube Q2 is turned on, the potential of the signal sending end is pulled down to the ground potential, and the signal sending end outputs the K-RX signal with low level. In summary, when the communication is performed, the level of the K-RX signal output by the signal sending end corresponds to the level of the K bus voltage, and the level of the K bus voltage corresponds to the level of the K-TX signal input by the signal input end, and the level of the K-RX signal corresponds to the level of the K-TX signal, so as to complete the signal communication.

[0038] Further, the signal sending module further comprises an acceleration unit, the acceleration unit comprising a resistor R18 and a capacitor C16, one end of the resistor R18 being connected with one end of a resistor R21, the other end of the resistor R18 being connected with the second electrode of a switch tube Q1 and the other end of the resistor R21 through the capacitor C16.

[0039] The signal sending module further comprises a voltage stabilizing diode D7, the negative electrode of the voltage stabilizing diode D7 being connected with one end of the resistor R21, one end of a resistor R42 and the second electrode of the switch tube Q1, and the positive electrode of the voltage stabilizing diode D7 being grounded.

[0040] Specifically, the resistor R18 and the capacitor C16 are used to accelerate the switching speed of the switch tube Q1 in the off state and the saturation state, thereby increasing the switching speed of the switch tube Q1, and the voltage stabilizing diode D7 is used to clamp the base-emitter voltage of the switch tube Q1 to prevent overvoltage breakdown of the switch tube Q1.

[0041] The K-line communication circuit can be used to realize signal communication between the master node and the slave node, and in application, the signal output ends of the master node and the slave node are respectively connected with the K bus through a signal receiving module, and the signal input ends of the master node and the slave node are respectively connected with the K bus through a signal sending module, when the master node sends a signal to the slave node, the signal output end of the master node outputs a K-TX signal to the signal receiving module connected with the master node, and the signal input end of the slave node receives a corresponding K-RX signal through the signal sending end connected with the slave node; when the slave node sends a signal to the master node, the signal output end of the slave node outputs a K-TX signal to the signal receiving module connected with the slave node, and the signal input end of the master node receives a corresponding K-RX signal through the signal sending end connected with the master node, so as to realize K-line communication between the master node and the slave node, and the slave node can be one or more.

[0042] In the embodiment, the K-line communication circuit is applied to an electric vehicle, including a two-wheeled electric vehicle, as shown in the figure. Figure 2 The master node is an alarm of the electric vehicle, and two slave nodes are respectively an instrument and an electronic seat lock, and in communication, the master node is allowed to interact with the slave nodes one by one in a polling manner. In specific implementation, more components of the electric vehicle can be set as the slave nodes according to communication requirements.

[0043] The preferred embodiments of the utility model are described above, and the utility model is not limited to the above embodiments. It can be understood that other improvements and changes directly derived or thought by those skilled in the art without departing from the spirit and concept of the utility model should be considered to be included in the protection scope of the utility model.

Claims

1. A K-line communication circuit for an electric vehicle, characterized by comprising: The overvoltage and undervoltage protection module, the signal receiving module and the signal sending module are connected with the K bus, The overvoltage and undervoltage protection module is used for providing overvoltage and undervoltage protection for the K bus, and comprises a fuse F1 and a TVS tube D5. The signal receiving module comprises a signal receiving end, and the signal sending module comprises a signal sending end.

2. The K-line communication circuit for an electric vehicle according to claim 1, wherein The signal receiving end is connected with the second electrode of the switch tube Q3 and one end of the resistor R3 through the resistor R11, the first electrode of the switch tube Q3 is connected with the other end of the resistor R3 and is connected to the first power voltage, the third electrode of the switch tube Q3 is connected with the second electrode of the switch tube Q7 and one end of the resistor R20 through the resistor R14, the other end of the resistor R20 is grounded, and the third electrode of the switch tube Q7 is connected with the K bus. The signal receiving module further comprises an overcurrent protection unit, and the overcurrent protection unit comprises a switch tube Q8, a resistor R26 and a resistor R47.

3. The K-line communication circuit for an electric vehicle according to claim 2, wherein The first electrode of the switch tube Q8 is grounded, the second electrode of the switch tube Q8 is connected with the first electrode of the switch tube Q7 and one end of the resistor R47 through the resistor R26, the other end of the resistor R47 is grounded, and the third electrode of the switch tube Q8 is connected with the second electrode of the switch tube Q7. The K bus is connected with the cathode of the diode D3 through the resistor R12, and the anode of the diode D3 is connected to the second power voltage.

4. The K-line communication circuit for an electric vehicle according to claim 3, wherein The signal sending module comprises a switch tube Q1, a switch tube Q2, a resistor R13, a resistor R19, a resistor R21, a resistor R42, a resistor R49 and a resistor R50.

5. The K-line communication circuit for an electric vehicle according to claim 4, wherein One end of the resistor R21 is connected with the K bus, the other end of the resistor R21 is connected with one end of the resistor R42 and the second electrode of the switch tube Q1, and the other end of the resistor R42 and the first electrode of the switch tube Q1 are grounded. The third electrode of the switch tube Q1 is connected with the resistor R13 and one end of the resistor R19, the other end of the resistor R13 is connected to the first power voltage, the other end of the resistor R19 is connected with the second electrode of the switch tube Q2, the third electrode of the switch tube Q2 is connected with one end of the resistor R49 and the resistor R50, the other end of the resistor R49 is connected to the first power voltage, the other end of the resistor R50 is connected with the signal sending end, and the first electrode of the switch tube Q2 is grounded. The first power voltage is 3.3V, and the second power voltage is 12V.

6. The K-line communication circuit for an electric vehicle according to claim 5, wherein ​ 7. The K-line communication circuit for an electric vehicle according to claim 5, wherein The signal sending module further comprises an acceleration unit, the acceleration unit comprises a resistor R18 and a capacitor C16, one end of the resistor R18 is connected with one end of a resistor R21, the other end of the resistor R18 is connected with the second electrode of a switch tube Q1 and the other end of the resistor R21 through the capacitor C16.

8. The K-line communication circuit for an electric vehicle according to claim 7, wherein The switch tube Q1, the switch tube Q2, the switch tube Q3, the switch tube Q7 and the switch tube Q8 are triodes.

9. The K-line communication circuit for an electric vehicle according to claim 7, wherein The signal sending module further comprises a voltage stabilizing diode D7, the negative electrode of the voltage stabilizing diode D7 is connected with one end of the resistor R21, one end of a resistor R42 and the second electrode of the switch tube Q1, and the positive electrode of the voltage stabilizing diode D7 is grounded.

10. The K-line communication circuit for an electric vehicle according to claim 1, wherein The fuse F1 is a recoverable fuse.

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