CN216795020U - CAN controller unit, CAN bus anti-impact protection device and CAN network - Google Patents
CAN controller unit, CAN bus anti-impact protection device and CAN network Download PDFInfo
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- CN216795020U CN216795020U CN202123400650.XU CN202123400650U CN216795020U CN 216795020 U CN216795020 U CN 216795020U CN 202123400650 U CN202123400650 U CN 202123400650U CN 216795020 U CN216795020 U CN 216795020U
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Abstract
The utility model relates to a CAN controller unit, a CAN bus anti-impact protection device and a CAN network, wherein one end of the CAN bus unit is connected with CAN bus equipment, and the other end of the CAN bus unit is connected with a thermistor RT1 and a thermistor RT 2; the other ends of the thermistor RT1 and the thermistor RT2 are connected with the TVS in parallel and then connected with the CAN interface of the CAN controller unit. According to the utility model, the anti-impact protection circuit is additionally arranged between the CAN control chip and the CAN bus interface, when high voltage exists between differential signal lines of the CAN bus (for example, a twisted pair of a CAN network is connected to 220V commercial power of a construction site), high-voltage impact at two ends of the TVS tube CAN quickly change high impedance at two ends of the TVS tube into low impedance, the voltage at two ends of the TVS tube is limited to clamp voltage, and meanwhile, the generated large current CAN be heated and consumed on resistors of a high-order signal line and a low-order signal line of the bus, so that the CAN control chip is protected from being damaged by high-voltage impact.
Description
Technical Field
The utility model belongs to the technical field of CAN bus communication, and particularly relates to a CAN controller unit, a CAN bus protection device and a CAN communication network.
Background
CAN (controller area network) is a controller area network, and the CAN bus specification is set by the international organization for standardization as international standard ISO 11898. The CAN communication circuit adopts a plurality of new technologies and unique designs, has the characteristics of low cost, high reliability, real-time property, flexibility, strong anti-interference capability and the like, is widely applied to the fields of automobile electronics, automatic control, electric power systems and the like, and has incomparable superiority with a CAN bus.
When the product adopts a CAN communication mode, the situation of wiring errors caused by wrong operation of workers on a construction site is inevitable, for example, a CAN signal line is accessed to a strong electric circuit of the construction site; or the installation environment is severe, and strong static electricity caused by electromagnetic interference exists. High voltage or large current CAN be loaded on a CAN controller through a differential communication line of a CAN network to cause damage and even accidents, so that the construction site with a CAN communication mode at present has higher requirements on the quality of field installation constructors and the installation environment.
SUMMERY OF THE UTILITY MODEL
The utility model aims to provide a CAN controller unit and a CAN bus anti-impact protection device, which are used for solving the problem of risk of damage of the CAN controller unit caused by high voltage and heavy current on a construction site; and meanwhile, the CAN network is provided for solving the problem that the construction site of the CAN communication mode has high requirements on the quality of installation constructors and the installation environment.
In order to achieve the above object, the scheme of the utility model comprises:
the CAN controller unit comprises a CAN control chip and a CAN bus interface which is connected with a CAN bus, wherein the CAN bus interface comprises a CAN high-level signal interface and a CAN low-level signal interface; the CAN high-level signal interface is connected with a CAN control chip CAN-H pin in series through a resistor, and the CAN low-level signal interface is connected with a CAN control chip CAN-L pin in series through a resistor; and a transient voltage suppression diode (TVS) is connected in parallel between the CAN-H pin and the CAN-L pin of the CAN control chip.
According to the CAN control unit, the anti-impact protection circuit is additionally arranged between the CAN control chip and the CAN bus interface, when high voltage exists between differential signal lines of the CAN bus (for example, a twisted pair of a CAN network is connected to 220V commercial power of a construction site), high-voltage impact at two ends of the TVS tube CAN enable high impedance at two ends of the TVS tube to be rapidly changed into low impedance, voltage at two ends of the TVS tube is limited to clamp voltage, and meanwhile, generated large current CAN be heated and consumed on resistors of a high-order signal line and a low-order signal line of the bus, so that the CAN control chip is protected from being damaged by high-voltage impact.
Further, the resistors are all positive temperature coefficient thermistors.
The thermistor with the positive temperature coefficient is adopted, when the CAN control chip is subjected to large current, the current intensity CAN be rapidly attenuated along with the rise of the heating resistance value of the resistor, and the CAN control chip is prevented from being impacted by the large current. Meanwhile, when the TVS clamps the transient high voltage to the parameter voltage, the thermistor CAN be rapidly increased by the large current generated on the thermistor, so that the resistance value is increased, and the transmission of a high-voltage signal to the CAN control chip is cut off.
Further, the transient voltage suppression diode is a bipolar TVS tube.
No matter what kind of mode the CAN signal line connects the mistake, no matter high order signal line electric potential is high or low order signal line electric potential is high, the homoenergetic obtains effective protection through two-way TVS pipe.
Further, the maximum clamping voltage Vc value of the bipolar TVS tube is less than the lowest tolerance voltage of the CAN control chip and greater than the maximum working voltage.
Through the parameter setting of TVS pipe, effectively protect CAN control chip to suffer the impact that is higher than its withstand voltage, also guarantee CAN communication's normal, prevent that effective signal from being filtered.
The utility model discloses an anti-impact protection device for a CAN bus, which comprises a CAN bus interface connected with the CAN bus and a CAN controller interface connected with a CAN controller; the CAN bus interface comprises a CAN high-level signal interface and a CAN low-level signal interface, and the CAN controller interface comprises a CAN high-level controller interface used for being connected with a CAN-H interface of the CAN controller and a CAN low-level controller interface used for being connected with a CAN-L interface of the CAN controller; a resistor is connected in series between the CAN high-level signal interface and the CAN high-level controller interface, and a resistor is also connected in series between the CAN low-level signal interface and the CAN low-level controller interface; and a transient voltage suppression diode is also connected in parallel between the CAN high-level controller interface and the CAN low-level controller interface.
The CAN bus anti-impact device is correspondingly connected to the high-level and low-level signal lines between the CAN controller and the CAN bus, so that the CAN controller is protected from being impacted by high voltage, the CAN controller is prevented from being damaged, and the reliability of a CAN network is improved.
Further, the resistors are all positive temperature coefficient thermistors.
The thermistor with the positive temperature coefficient is adopted, when the CAN control chip is subjected to large current, the current intensity CAN be rapidly attenuated along with the rise of the heating resistance value of the resistor, and the CAN control chip is prevented from being impacted by the large current. Meanwhile, when the TVS clamps the transient high voltage to the parameter voltage, the thermistor CAN be rapidly increased by the large current generated on the thermistor, so that the resistance value is increased, and the transmission of a high-voltage signal to the CAN control chip is cut off.
Further, the transient voltage suppression diode is a bipolar TVS tube.
The TVS diode in the protection device provided by the utility model is a bipolar bidirectional TVS tube to bear pulse or high voltage impact from two directions, so that the CAN controller is prevented from being damaged by high voltage from two directions.
The CAN network comprises a CAN controller and a CAN bus unit, wherein the CAN controller is in communication connection with the CAN bus unit through a CAN high-level signal line and a CAN low-level signal line; the CAN high-order signal line is connected with the CAN low-order signal line through a transient voltage suppression diode, and the connection point of the transient voltage suppression diode and the CAN high-order signal line and the connection point of the transient voltage suppression diode and the CAN low-order signal line are both positioned between a CAN controller and a corresponding resistor.
The CAN network of the utility model adds the protection circuit between the CAN controller and the bus, and does not worry about high-voltage impact caused by wrong connection of lines and interference of severe electromagnetic environment, thereby reducing the dependence on the technical quality of constructors and the requirement on construction environment.
Further, the resistors are all positive temperature coefficient thermistors.
The thermistor with the positive temperature coefficient is adopted, when the CAN control chip is subjected to large current, the current intensity CAN be rapidly attenuated along with the rise of the heating resistance value of the resistor, and the CAN control chip is prevented from being impacted by the large current. Meanwhile, when the TVS clamps the transient high voltage to the parameter voltage, the thermistor CAN be rapidly increased by the large current generated on the thermistor, so that the resistance value is increased, and the transmission of a high-voltage signal to the CAN control chip is cut off.
Further, the transient voltage suppression diode is a bipolar TVS tube.
The TVS diode in the protection device provided by the utility model is a bipolar bidirectional TVS tube to bear pulse or high voltage impact from two directions, so that the CAN controller is prevented from being damaged by high voltage from two directions.
Drawings
Fig. 1 is a schematic diagram of the anti-shock protection circuit of the CAN bus of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings.
CAN network embodiment:
the CAN network comprises a CAN bus unit and a CAN controller unit, wherein the CAN bus unit comprises a plurality of communication devices mounted on a CAN bus, the CAN bus unit is connected with the CAN controller unit through the CAN bus, the CAN bus comprises a high-order signal line (CAN-H) and a low-order signal line (CAN-L), and the CAN controller unit comprises a CAN control chip (CAN controller).
On a CAN bus between the CAN bus unit and the CAN controller unit, a thermistor RT1 is connected in series in a high-order signal line, and a thermistor RT2 is connected in series in a low-order signal line.
A transient voltage suppression diode TVS is connected in parallel between a high-order signal port (CAN H) and a low-order signal port (CAN L) of the CAN controller unit. The TVS diode is a bipolar bidirectional TVS tube to bear pulse or high voltage impact from two directions, so that the CAN controller is prevented from being damaged by high voltage from two directions.
The output signal of CAN bus unit high-order signal line is limited by thermistor RT1 and then is protected by bidirectional TVS tube, and is connected to CAN controller unit high-order signal port, the CAN controller unit detects the high-order signal port signal, and outputs from CAN controller unit low-order signal port after processing, and returns to CAN bus unit low-order signal line after being limited by bidirectional TVS tube voltage and thermistor RT2, and the process is transient process, and vice versa.
The thermistor RT1, the transient voltage suppression diode TVS and the thermistor RT2 are connected in series to form a protection circuit with 4 interfaces, and the protection circuit is packaged to form a protection unit. Two contacts of the TVS, the thermistor RT1 and the thermistor RT2 respectively form a CAN H port and a CAN L port of the protection unit, and the other two terminals of the thermistor RT1 and the thermistor RT2 form a bus high-level port and a bus low-level port of the protection unit; the CAN H port and the CAN L port are respectively used for connecting a high-level signal port and a low-level signal port of the CAN controller unit, and the bus high-level port and the bus low-level port are used for connecting a high-level signal line and a low-level signal line of the CAN bus unit.
The thermistors RT1 and RT2 adopt positive temperature coefficient thermistors, have current limiting and thermal protection functions, are small in resistance value during low current, and increase in resistance value along with the increase of current according to the characteristics of the positive temperature coefficient thermistors during high current, so that the strength of input signals CAN be attenuated, and the situation that high-voltage signals are led to a CAN controller unit to cause device damage is avoided. The resistors at the RT1 and RT2 positions in the figure CAN also be common resistors, and are only used for attenuating large current on the CAN bus when the TVS clamps so as to protect bus equipment on the CAN bus from being damaged by the large current.
The bidirectional TVS tube is a voltage protection type device and can clamp the transient voltage to a parameter voltage (the cut-off state voltage of the TVS diode is also the clamping voltage Vc). The thermistor RT1, the thermistor RT2 and the TVS form a current and voltage dual protection unit, when the external voltage (or transient high-voltage pulse) of the CAN bus unit is higher than the clamping voltage of the TVS tube, larger current CAN be generated at two ends of the thermistors RT1 and RT2 in a transient state, and the resistance value and the voltage of the thermistors RT1 and RT2 are increased after the heat is generated due to the increase of the current. Thereby cutting off the transmission of the input high voltage signal to the CAN controller unit.
When the TVS is in type selection, the maximum clamping voltage Vc in the parameters of the TVS is ensured to be smaller than the withstand voltage of the CAN controller and larger than the maximum working voltage between a high-order signal line and a low-order signal line of a working CAN bus. The CAN controller is prevented from being damaged by voltages at two ends of the TVS which are larger than the self withstand voltage, and meanwhile, the normal signal voltage is prevented from being distorted or filtered after being clamped by the TVS.
In conclusion, the CAN bus controller CAN effectively prevent the CAN bus unit from being damaged or machines from being damaged due to wiring errors or instant high-voltage pulses.
CAN bus protecting against shock device embodiment:
the anti-impact protection device for the CAN bus is a 4-port device protection unit in the embodiment of the CAN network and the figure 1, and the protection unit is correspondingly connected and arranged between the CAN controller unit and the CAN bus unit, so that the anti-misconnection high-voltage and transient high-voltage pulse protection for the CAN controller CAN be realized. Since the description of the protection unit in the above embodiments is sufficiently clear, it is not described here in detail.
CAN controller unit embodiment:
the CAN controller unit comprises a CAN control chip, a 4-interface protection circuit in a protection unit in a CAN network embodiment is integrated on a printed board where the CAN control chip is arranged as a protection circuit, two contacts of a TVS, a thermistor RT1 and a thermistor RT2 in the protection circuit are respectively connected with a CAN-H pin and a CAN-L pin of the CAN control chip, and the other two terminals of the thermistor RT1 and the thermistor RT2 in the protection circuit are used as a high-order signal port (CAN H) and a low-order signal port (CAN L) of the CAN controller unit and are used for connecting a high-order signal line and a low-order signal line of a CAN bus unit. Since the description of the protection circuit in the above embodiments is sufficiently clear, it is not described here in detail.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various changes and modifications can be made without departing from the overall concept of the utility model, and these should also be considered as the protection scope of the present invention.
Claims (10)
1. A CAN controller unit comprises a CAN control chip and a CAN bus interface connected with a CAN bus, wherein the CAN bus interface comprises a CAN high-level signal interface and a CAN low-level signal interface; the CAN high-level signal interface is connected with a CAN control chip CAN-H pin in series through a resistor, and the CAN low-level signal interface is connected with a CAN control chip CAN-L pin in series through a resistor; and a transient voltage suppression diode is also connected in parallel between the CAN-H pin and the CAN-L pin of the CAN control chip.
2. The CAN controller unit of claim 1, wherein said resistors are all positive temperature coefficient thermistors.
3. The CAN controller unit of claim 2, wherein said transient voltage suppression diode is a bipolar TVS transistor.
4. The CAN controller unit of claim 3 wherein the maximum clamping voltage Vc of the bipolar TVS transistor is less than the lowest withstand voltage of the CAN control chip and greater than the maximum operating voltage of the CAN bus.
5. A CAN bus anti-impact protection device is characterized by comprising a CAN bus interface used for being connected with a CAN bus and a CAN controller interface used for being connected with a CAN controller; the CAN bus interface comprises a CAN high-level signal interface and a CAN low-level signal interface, and the CAN controller interface comprises a CAN high-level controller interface used for being connected with a CAN-H interface of the CAN controller and a CAN low-level controller interface used for being connected with a CAN-L interface of the CAN controller; a resistor is connected in series between the CAN high-level signal interface and the CAN high-level controller interface, and a resistor is also connected in series between the CAN low-level signal interface and the CAN low-level controller interface; and a transient voltage suppression diode is also connected in parallel between the CAN high-level controller interface and the CAN low-level controller interface.
6. The CAN-bus shock protection device of claim 5, wherein the resistors are positive temperature coefficient thermistors.
7. The CAN bus anti-shock protection device of claim 6, wherein the transient voltage suppression diode is a bipolar TVS transistor.
8. A CAN network comprises a CAN controller and a CAN bus unit, wherein the CAN controller is in communication connection with the CAN bus unit through a CAN high-level signal line and a CAN low-level signal line; the CAN high-order signal line is connected with the CAN low-order signal line through a transient voltage suppression diode, and the connection point of the transient voltage suppression diode and the CAN high-order signal line and the connection point of the transient voltage suppression diode and the CAN low-order signal line are both positioned between a CAN controller and a corresponding resistor.
9. The CAN network of claim 8 wherein the resistors are all positive temperature coefficient thermistors.
10. The CAN network of claim 9 wherein said transient voltage suppression diode is a bipolar TVS transistor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202123400650.XU CN216795020U (en) | 2021-12-30 | 2021-12-30 | CAN controller unit, CAN bus anti-impact protection device and CAN network |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202123400650.XU CN216795020U (en) | 2021-12-30 | 2021-12-30 | CAN controller unit, CAN bus anti-impact protection device and CAN network |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN216795020U true CN216795020U (en) | 2022-06-21 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202123400650.XU Active CN216795020U (en) | 2021-12-30 | 2021-12-30 | CAN controller unit, CAN bus anti-impact protection device and CAN network |
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| Country | Link |
|---|---|
| CN (1) | CN216795020U (en) |
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2021
- 2021-12-30 CN CN202123400650.XU patent/CN216795020U/en active Active
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