CN210112034U

CN210112034U - CAN transceiver circuit and CAN communication system

Info

Publication number: CN210112034U
Application number: CN201920521546.XU
Authority: CN
Inventors: 杜志峰; 熊晖; 杨学实
Original assignee: Guangzhou Heng Zhong Car Network Intelligent Electronic Technology Co Ltd
Current assignee: Guangzhou Hengzhong Internet Of Vehicles Technology Co ltd
Priority date: 2019-04-17
Filing date: 2019-04-17
Publication date: 2020-02-21
Anticipated expiration: 2029-04-17

Abstract

The utility model relates to a CAN transceiver circuit and CAN communication system, when the controlled end of second controlled switch inserts CAN control system and sends logic high level, first controlled switch all switches on with the second controlled switch, and first switch end output logic high level of first controlled switch is as high level CAN voltage, and the first switch end output logic low level of second controlled switch is as CAN low-voltage, simultaneously, makes the output of receiving data output module to CAN control system output logic low level signal. Based on the CAN bus network, the complete transceiving function between the CAN bus network and the CAN control system is realized through the control data sending module, the control data receiving module and the received data output module. Furthermore, the control data sending module adopts the first controlled switch and the second controlled switch and other discrete modules, so that the control data sending module is convenient to replace, and the driving capability of the logic high level and the logic low level output to the CAN bus network is adjusted to adapt to the requirements of different application environments.

Description

CAN transceiver circuit and CAN communication system

Technical Field

The utility model relates to a bus control technical field especially relates to a CAN transceiver circuit and CAN communication system.

Background

A CAN (Controller Area Network) bus is a serial communication Network that effectively supports distributed control and real-time control, and is one of the most widely used field buses in the world at present. The CAN bus typically includes a CAN control system, a CAN transceiver, and a CAN bus network. The CAN transceiver is used as a core component of a CAN bus, is used for receiving and sending data under the control of a CAN control system, and is a bridge for connecting the CAN control system and a CAN bus network.

The conventional way of constructing the CAN transceiver is to directly use a general-purpose CAN transceiver chip. The port for realizing the function in the CAN transceiver chip mainly comprises: a transmit data input terminal TXD, a receive data output terminal RXD, a high level CAN voltage input/output terminal CANH, and a low level CAN voltage input/output terminal CANL. The transmitting data input end TXD and the receiving data output end RXD of the CAN transceiver chip are both used for being connected with a CAN control system, and the high-level CAN voltage input/output end CANH and the low-level CAN voltage input/output end CANL of the CAN transceiver chip are both used for being connected with a CAN bus network. And complete CAN bus transceiving control is realized according to the working logic among the data transmitting input end TXD, the data receiving output end RXD, the high-level CAN voltage input/output end CANH and the low-level CAN voltage input/output end CANL.

However, performance parameters and indexes of the CAN transceiver chip are constrained by the chip design, such as the number of access devices is fixed or the isolation is fixed, i.e. the indexes are fixed and cannot be adjusted, which is difficult to meet the requirements in the complex application environment.

SUMMERY OF THE UTILITY MODEL

Therefore, it is necessary to provide a CAN transceiver circuit and a CAN communication system for the purpose that performance parameters and indexes of a CAN transceiver chip are constrained by chip design, the indexes are fixed and cannot be adjusted, and the application under a complex application environment is difficult to meet.

A CAN transceiver circuit comprises a control data sending module, a control data receiving module and a received data output module;

the control data sending module comprises a first controlled switch and a second controlled switch; the first switch end of the first controlled switch is used for connecting a CAN bus network and is used as a high-level CAN voltage input/output end; the second switch end of the first controlled switch is used for switching in a logic high level; the controlled end of the first controlled switch is connected with the first switch end of the second controlled switch; the first switch end of the second controlled switch is also used for connecting a CAN bus network and is used as a low-level CAN voltage input/output end; the second switch end of the second controlled switch is used for switching in a logic low level; the controlled end of the second controlled switch is used for connecting the CAN control system and is used as a data sending input end; the first controlled switch is used for conducting a first switch end and a second switch end of the first controlled switch when a controlled end of the first controlled switch is connected to a logic low level; the second controlled switch is used for conducting a first switch end and a second switch end of the second controlled switch when the controlled end of the second controlled switch is connected to a logic high level;

a first receiving end of the control data receiving module is connected with a first switch end of the first controlled switch, and a second receiving end of the control data receiving module is connected with a first switch end of the second controlled switch; the control data receiving module is used for outputting a first logic level to the received data output module when the controlled end of the second controlled switch is connected with a logic high level; the control data receiving module is also used for outputting a second logic level to the received data output module when the controlled end of the second controlled switch is connected with the logic low level;

the input end of the received data output module is used for accessing a first logic level or a second logic level; the output end of the received data output module is used for connecting a CAN control system and is used as a received data output end; the receiving data output module is used for outputting a logic low level to the CAN control system according to the first logic level, and the receiving data output module is used for outputting a logic high level to the CAN control system according to the second logic level.

When the controlled end of the second controlled switch is connected to the CAN control system to send a logic high level, the first controlled switch and the second controlled switch are both switched on, the first switch end of the first controlled switch outputs the logic high level as a high-level CAN voltage, the first switch end of the second controlled switch outputs the logic low level as a CAN low voltage, and meanwhile, the output end of the data receiving output module outputs a logic low level signal to the CAN control system. Based on the CAN bus network, the complete transceiving function between the CAN bus network and the CAN control system is realized through the control data sending module, the control data receiving module and the received data output module. Furthermore, the control data sending module adopts the first controlled switch and the second controlled switch and other discrete modules, so that the control data sending module is convenient to replace, and the driving capability of the logic high level and the logic low level output to the CAN bus network is adjusted to adapt to the requirements of different application environments.

In one embodiment, the control data transmission module further comprises a first isolation unit and a second isolation unit;

the first switch end of the first controlled switch is used for being connected with the CAN bus network through the first isolation unit; and the first switch end of the second controlled switch is used for connecting the CAN bus network through the second isolation unit.

In one embodiment, the first isolation unit comprises a first diode, and the second isolation unit comprises a second diode;

the first switch end of the first controlled switch is connected with the anode of a first diode, and the cathode of the first diode is used for connecting a CAN bus network;

and the first switch end of the second controlled switch is connected with the cathode of a second diode, and the anode of the second diode is used for connecting the CAN bus network.

In one embodiment, the control data sending module further comprises a first voltage dividing module and a second voltage dividing module;

the controlled end of the first controlled switch is used for accessing a logic high level through the first voltage division module; the controlled end of the first controlled switch is also used for being connected with the first switch end of the second controlled switch through the second voltage division module.

In one embodiment, the first controlled switch and the second controlled switch each comprise a semiconductor switch.

In one embodiment, the first controlled switch comprises a first PNP transistor; the second controlled switch comprises a first NPN triode;

the collector of the first PNP triode is used for connecting a CAN bus network and is used as a high-level CAN voltage input/output end; the emitter of the first PNP triode is used for accessing a logic high level; the base electrode of the first PNP triode is connected with the collector electrode of the first NPN triode; the collector of the first NPN triode is also used for connecting a CAN bus network and is used as a low-level CAN voltage input/output end; an emitter of the first NPN triode is used for accessing a logic low level; and the base electrode of the first NPN triode is used for being connected with the CAN control system and used as a data sending input end.

In one embodiment, the control data receiving module comprises a third controlled switch, a fourth controlled switch and a third voltage dividing module;

the controlled end of the third controlled switch is connected with the first switch end of the first controlled switch, and the first switch end of the third controlled switch is used for accessing a logic high level; the second switch end of the third controlled switch is connected with the second switch end of the fourth controlled switch; the third controlled switch is used for conducting a first switch end and a second switch end of the third controlled switch when the controlled end of the third controlled switch is connected to a logic high level;

the controlled end of the fourth controlled switch is connected with the first switch end of the second controlled switch, and the first switch end of the fourth controlled switch is used for accessing a logic low level through the third voltage division module; the fourth controlled switch is used for conducting the first switch end and the second switch end of the fourth controlled switch when the controlled end of the fourth controlled switch is switched into a logic low level

In one embodiment, the third controlled switch and the fourth controlled switch each comprise a semiconductor switch.

In one embodiment, the third controlled switch comprises a second NPN transistor, and the fourth controlled switch comprises a second PNP transistor;

the base electrode of the second NPN triode is connected with the first switch end of the first controlled switch, and the collector electrode of the second NPN triode is used for accessing a logic high level; the emitter of the second NPN triode is connected with the emitter of the second PNP triode;

and the base electrode of the second PNP triode is connected with the first switch end of the second controlled switch, and the collector electrode of the second PNP triode is used for being connected with a logic low level through the third voltage division module.

In one embodiment, the control data receiving module further comprises a first bias resistor, a second bias resistor, a third bias resistor, a fourth bias resistor, a fifth bias resistor and a sixth bias resistor;

the base electrode of the second NPN triode is connected with the first switch end of the first controlled switch through a first biasing resistor, and the base electrode of the second NPN triode is used for being connected with a logic high level through a third biasing resistor and a fifth biasing resistor in sequence;

the base electrode of the second PNP triode is connected with the first switch end of the second controlled switch through a second bias resistor; the base electrode of the second PNP triode is used for being connected with a logic low level sequentially through the fourth biasing resistor and the sixth biasing resistor;

and the common end of the third bias resistor and the fifth bias resistor is connected with the common end of the fourth bias resistor and the sixth bias resistor.

In one embodiment, the control data receiving module further comprises a first filter capacitor and a second filter capacitor;

and the base electrode of the second NPN triode is used for being switched into a logic low level through the first filter capacitor, and the base electrode of the second PNP triode is used for being switched into the logic low level through the second filter capacitor.

In one embodiment, the received data output module comprises a fifth controlled switch and a pull-up module;

the controlled end of the fifth controlled switch is used for accessing the first logic level or the second logic level, the first switch end of the fifth controlled switch is used for accessing the logic high level through the pull-up module, and the first switch end of the fifth controlled switch is used for connecting the CAN control system; the second switch end of the fifth controlled switch is used for switching in a logic low level;

the fifth controlled switch is used for conducting the first switch end and the second switch end of the fifth controlled switch when the controlled end of the fifth controlled switch is connected to the first logic level.

In one embodiment, the fifth controlled switch comprises a semiconductor switch.

In one embodiment, the fifth controlled switch comprises a third NPN transistor;

a base electrode of the third NPN triode is used for being connected with the first logic level or the second logic level, a collector electrode of the third NPN triode is used for being connected with the logic high level through the pull-up module, and the collector electrode of the third NPN triode is used for being connected with the CAN control system; and the emitter of the third NPN triode is used for switching in a logic low level.

A CAN communication system comprises a CAN control system, a CAN bus network and the CAN transceiver circuit of any one of the embodiments.

According to the CAN communication system, when the controlled end of the second controlled switch is connected to the CAN control system to send a logic high level, the first controlled switch and the second controlled switch are both switched on, the first switch end of the first controlled switch outputs the logic high level as a high-level CAN voltage, the first switch end of the second controlled switch outputs the logic low level as a CAN low voltage, and meanwhile, the output end of the data receiving output module outputs a logic low level signal to the CAN control system. Based on the CAN bus network, the complete transceiving function between the CAN bus network and the CAN control system is realized through the control data sending module, the control data receiving module and the received data output module. Furthermore, the control data sending module adopts the first controlled switch and the second controlled switch and other discrete modules, so that the control data sending module is convenient to replace, and the driving capability of the logic high level and the logic low level output to the CAN bus network is adjusted to adapt to the requirements of different application environments.

Drawings

FIG. 1 is a block diagram of a CAN transceiver circuit module according to an embodiment;

FIG. 2 is a circuit diagram of a control data transmission module according to an embodiment;

FIG. 3 is a block diagram of a control data transmission module according to another embodiment;

FIG. 4 is a circuit diagram of a control data transmission module according to another embodiment;

FIG. 5 is a block diagram of a control data transmission module according to still another embodiment;

FIG. 6 is a circuit diagram of a control data transmission module according to yet another embodiment;

FIG. 7 is a block diagram of a control data receiving module according to one embodiment;

FIG. 8 is a circuit diagram of a control data receiving module according to one embodiment;

FIG. 9 is a block diagram of a received data output module according to one embodiment;

FIG. 10 is a circuit diagram of a receive data output module according to one embodiment;

fig. 11 is a diagram of a CAN communication system architecture according to an embodiment.

Detailed Description

For better understanding of the objects, technical solutions and technical effects of the present invention, the present invention will be further explained with reference to the accompanying drawings and embodiments. It is to be noted that the following examples are only for explaining the present invention and are not intended to limit the present invention.

The embodiment of the utility model provides a CAN transceiver circuit.

Fig. 1 is a block diagram of a CAN transceiver circuit according to an embodiment, and as shown in fig. 1, the CAN transceiver circuit according to an embodiment includes a control data transmitting module 10, a control data receiving module 11, and a received data output module 12;

the control data transmission module 10 includes a first controlled switch 100 and a second controlled switch 101; the first switch terminal K1 of the first controlled switch 100 is used for connecting a CAN bus network as a high-level CAN voltage input/output terminal CANH; the second switch terminal K2 of the first controlled switch 100 is used for switching on a logic high level; the controlled terminal B1 of the first controlled switch 100 is connected with the first switch terminal K3 of the second controlled switch 101; the first switch terminal K3 of the second controlled switch 101 is further configured to connect to a CAN bus network as a low-level CAN voltage input/output terminal CANL; the second switch terminal K4 of the second controlled switch 101 is used for switching on a logic low level; the controlled end B2 of the second controlled switch 101 is used for connecting the CAN control system and is used as a transmission data input end TXD; the first controlled switch 100 is configured to turn on the first switch terminal K1 and the second switch terminal K2 of the first controlled switch 100 when the controlled terminal B1 of the first controlled switch 100 is switched to a logic low level; the second controlled switch 101 is configured to turn on the first switch terminal K3 and the second switch terminal K4 of the second controlled switch 101 when the controlled terminal B2 of the second controlled switch 101 is switched to a logic high level;

the controlled terminal B2 of the second controlled switch 101 is used as a transmitting data input terminal TXD and is connected to the CAN control system to receive the control data transmitted by the CAN control system. The control data transmitted by the conventional CAN control system includes a high level and a low level. In this embodiment, the high level sent by the CAN control system is consistent with the logic high level, and the low level sent by the CAN control system is consistent with the logic low level.

For convenience of explanation, the present embodiment uses the level of the voltage higher than the set threshold as the logic high level, and uses the ground signal as the logic low level. It should be noted that, the logic high level and the logic low level may also select other level signals with specific sizes on the premise of satisfying the working relationship of each module in this embodiment, and are not limited to the above definition.

In one embodiment, when the CAN control system sends out a logic high level, the controlled terminal B1 of the second controlled switch 101 receives a logic high level, and the first switch terminal K3 and the second switch terminal K4 thereof are turned on, so that a logic low level is transmitted to the controlled terminal B1 of the first controlled switch 100, and the first switch terminal K1 and the second switch terminal K2 are turned on. At this time, the high-level CAN voltage input/output terminal CANH is at a logic high level, and the low-level CAN voltage input/output terminal CANL is at a logic low level, so that serial differential transmission of the CAN bus network is realized.

In one embodiment, when the CAN control system sends out a logic low level, the controlled terminal B1 of the second controlled switch 101 receives the logic low level, and the first switch terminal K3 and the second switch terminal K4 thereof are turned off, so that the first switch terminal K1 and the second switch terminal K2 are also turned off. At this time, according to the characteristics of the control data receiving module 11, the high-level CAN voltage input/output terminal CANH is in a floating state or a high-impedance state, and the low-level CAN voltage input/output terminal CANL is in a floating state or a high-impedance state, thereby forming another communication state in the CAN bus network.

Based on this, the control data transmitting module 10 provides a signal level for the CAN bus network in a logic level manner according to the logic level output by the CAN control system. The driving capability of the CAN bus network is determined by the first controlled switch 100 and the second controlled switch 101.

It should be noted that, in the conventional CAN transceiver chip, each device in the CAN transceiver chip is highly integrated, which results in a fixed parameter index of the chip, that is, the driving capability of the CAN bus network is fixed, which results in a fixed number of accessed devices. In this embodiment, the first controlled switch 100 and the second controlled switch 101 are discrete components or discrete modules, and a user CAN change parameters of the control data transmitting module 10 by replacing the first controlled switch 100 or the second controlled switch 101, so as to change the driving capability of the control data transmitting module 10 to the CAN bus network.

In one embodiment, the first controlled switch 100 and the second controlled switch 101 may be electronic switches or semiconductor switches. As a preferred embodiment, the first controlled switch 100 and the second controlled switch 101 are semiconductor switches, including IGBT switching devices, triodes, and the like.

In one embodiment, fig. 2 is a circuit diagram of a control data transmitting module according to an embodiment, and as shown in fig. 2, the first controlled switch 100 includes a first PNP transistor Q1; the second controlled switch 101 includes a first NPN transistor Q2;

the collector of the first PNP triode Q1 is used for connecting a CAN bus network and is used as a high-level CAN voltage input/output end CANH; the emitter of the first PNP triode Q1 is used for switching in a logic high level VCC; the base electrode of the first PNP triode Q1 is connected with the collector electrode of the first NPN triode Q1; the collector of the first NPN triode Q1 is also used for connecting a CAN bus network and is used as a low-level CAN voltage input/output end CANL; an emitter of the first NPN triode Q2 is used for being connected with a logic low level GND; the base of the first NPN triode Q2 is used for connecting the CAN control system and is used as a data sending input end.

As shown in fig. 2, after the base of the first NPN transistor Q2 receives the logic high level sent by the CAN control system, the first NPN transistor Q2 is turned on, and the base of the first PNP transistor Q1 is pulled down to the logic low level, so that the first PNP transistor Q1 is turned on. At this time, the high level CAN voltage input/output terminal CANH is in a logic high state, and the low level CAN voltage input/output terminal CANL is in a logic low state.

As a preferred embodiment, the first PNP transistor Q1 and the first NPN transistor Q2 are T092 packaged transistors to increase the driving capability of the high level CAN voltage input/output terminal CANH and the low level CAN voltage input/output terminal CANL.

In one embodiment, as shown in fig. 2, the control data transmitting module 10 further includes a first current limiting resistor R1, and the base of the first NPN transistor Q2 is connected to the CAN control system through the first current limiting resistor R1.

In one embodiment, as shown in fig. 2, the control data transmission module 10 further includes a first driving resistor R2 and a second driving resistor R3;

the collector of the first PNP transistor Q1 is connected to the CAN bus network through a first driving resistor R2, and the collector of the first NPN transistor Q2 is connected to the CAN bus network through a second driving resistor R3.

The level driving capability of the collector of the first PNP triode Q1 is improved through the first driving resistor R2; the level driving capability of the collector of the first NPN transistor Q2 is improved by the second driving resistor R3. As a preferred embodiment, the first driving resistor R2 and the second driving resistor R3 are resistors with a resistance of 1k Ω, so as to effectively improve the level driving capability.

In one embodiment, fig. 3 is a structural diagram of a control data transmission module according to another embodiment, and as shown in fig. 3, the control data transmission module 10 according to another embodiment further includes a first isolation unit 200 and a second isolation unit 201;

the first switch terminal K1 of the first controlled switch 100 is used for connecting to the CAN bus network through the first isolation unit 200; the first switch end of the second controlled switch 101 is used to connect to the CAN bus network through the second isolation unit 201.

The first isolation unit 200 is configured to improve the isolation of the high-level CAN voltage input/output terminal CANH, and the second isolation unit 201 is configured to improve the isolation of the low-level CAN voltage input/output terminal CANL. In one embodiment, the first isolation unit 200 and the second isolation unit 201 may be implemented with separate isolation modules or isolation elements to facilitate replacement and adjustment of isolation between the high-level CAN voltage input/output terminal CANH and the low-level CAN voltage input/output terminal CANL.

In one embodiment, fig. 4 is a circuit diagram of a control data transmission module according to another embodiment, as shown in fig. 4, a first isolation unit 200 includes a first diode D1, and a second isolation unit 201 includes a second diode D2;

a first switch terminal K1 of the first controlled switch 100 is connected to the anode of a first diode D1, and the cathode of the first diode D1 is used for connecting to a CAN bus network;

the first switch terminal K3 of the second controlled switch 101 is connected to the cathode of the second diode D2, and the anode of the second diode D2 is used for connecting to the CAN bus network.

The isolation of the high-level CAN voltage input/output terminal CANH is realized by the first diode D1, and the isolation of the low-level CAN voltage input/output terminal CANL is realized by the second diode D2. In one embodiment, the first diode D1 and the second diode D2 CAN be high reverse voltage-withstanding diodes, so as to effectively improve the isolation between the high-level CAN voltage input/output terminal CANH and the low-level CAN voltage input/output terminal CANL.

In one embodiment, fig. 5 is a structural diagram of a control data transmission module according to yet another embodiment, and as shown in fig. 5, the control data transmission module 10 according to yet another embodiment further includes a first voltage division module 300 and a second voltage division module 301;

the controlled terminal B1 of the first controlled switch 100 is used for accessing the logic high level VCC through the first voltage dividing module 300; the controlled terminal B1 of the first controlled switch 100 is further used for connecting the first switch terminal K3 of the second controlled switch 101 through the second voltage dividing module 301.

The first voltage dividing module 300 and the second voltage dividing module 301 are configured to adjust a voltage difference between a logic high level and a logic low level, and change a level of the controlled terminal B1 of the first controlled switch 100. Meanwhile, when the first switch terminal K3 of the second controlled switch 101 is turned on at the second switch terminal K4, the first controlled switch 100 functions as a bias circuit to turn on the first switch terminal K1 and the second switch terminal K2.

In one embodiment, fig. 6 is a circuit diagram of a control data transmission module according to yet another embodiment, and as shown in fig. 6, the first voltage dividing module 300 includes a first voltage dividing resistor R4, and the second voltage dividing module 301 includes a second voltage dividing resistor R5.

In one embodiment, the first voltage dividing resistor R4 and the second voltage dividing resistor R5 are resistors with a resistance of 100k Ω.

A first receiving end of the control data receiving module 11 is connected to the first switch end K1 of the first controlled switch 100, and a second receiving end of the control data receiving module 11 is connected to the first switch end K3 of the second controlled switch 101; the control data receiving module 11 is configured to output a first logic level to the received data outputting module 12 when the controlled terminal B2 of the second controlled switch 101 is connected to the logic high level VCC; the control data receiving module 11 is further configured to output a second logic level to the received data output module 12 when the controlled terminal B2 of the second controlled switch 101 is connected to the logic low level GND;

when the controlled terminal B2 of the second controlled switch 101 is connected to the logic high level VCC, the first receiving terminal of the data receiving module 11 is controlled to be at the logic high level, the second receiving terminal of the data receiving module 11 is controlled to be at the logic low level, and the data receiving module 11 is controlled to output the first logic level to the received data output module 12. When the controlled terminal B2 of the second controlled switch 101 is connected to the logic low level GND, the first receiving terminal of the data receiving module 11 is controlled to be in a floating or high impedance state, and the second receiving terminal of the data receiving module 11 is controlled to be in a floating or high impedance state, which is equivalent to that the first receiving terminal and the second receiving terminal are both in a logic low level, so that the data receiving module 11 is controlled to output a second logic level to the received data output module 12.

In one embodiment, the control data receiving module 11 may be an integrated circuit chip or a circuit composed of discrete components.

In one embodiment, fig. 7 is a structural diagram of a control data receiving module according to an embodiment, and as shown in fig. 7, a control data receiving module 11 according to an embodiment includes a third controlled switch 400, a fourth controlled switch 401, and a third voltage dividing module 402;

the controlled terminal B3 of the third controlled switch 400 is connected to the first switch terminal K1 of the first controlled switch 100, and the first switch terminal K5 of the third controlled switch 400 is used for switching on a logic high level VCC; the second switch terminal K6 of the third controlled switch 400 is connected to the second switch terminal K8 of the fourth controlled switch 401; the third controlled switch 400 is configured to turn on the first switch terminal K5 and the second switch terminal K6 of the third controlled switch 400 when the controlled terminal B3 of the third controlled switch 400 is connected to the logic high level VCC;

the controlled terminal B4 of the fourth controlled switch 401 is connected to the first switch terminal K3 of the second controlled switch 101, and the first switch terminal K7 of the fourth controlled switch 401 is configured to switch in the logic low level GND through the third voltage dividing module 402; the fourth controlled switch 401 is configured to turn on the first switch terminal K7 and the second switch terminal K8 of the fourth controlled switch 401 when the controlled terminal B4 of the fourth controlled switch 401 is connected to the logic low level GND.

After the controlled terminal B2 of the second controlled switch 101 receives the logic high level sent by the CAN control system, the high-level CAN voltage input/output terminal CANH is at the logic high level, the low-level CAN voltage input/output terminal CANL is at the logic low level, at this time, the first switch terminal K5 and the second switch terminal K6 are turned on, and the first switch terminal K7 and the second switch terminal K8 are also turned on. Based on the third voltage division block 402, the logic high level is output as the first logic level to the input terminal of the received data output block 12. After the controlled terminal B2 of the second controlled switch 101 receives the logic low level sent by the CAN control system, the high-level CAN voltage input/output terminal CANH is at the logic high level, the low-level CAN voltage input/output terminals CANL are both at the logic low level, the first switch terminal K5 and the second switch terminal K6 are turned off, and the third voltage division module 402 outputs the logic low level as the second logic level to the input terminal of the received data output module 12.

In this embodiment, the third controlled switch 400 and the fourth controlled switch 401 are discrete components or discrete modules, and a user CAN change parameters of the control data transmitting module 10 by replacing the third controlled switch 400 or the fourth controlled switch 401, so as to change the driving capability of the control data transmitting module 10 to the CAN bus network.

In one embodiment, the third controlled switch 400 and the fourth controlled switch 401 may be electronic switches or semiconductor switches. As a preferred embodiment, the third controlled switch 400 and the fourth controlled switch 401 are semiconductor switches, including IGBT switching devices, triodes, and the like.

In one embodiment, fig. 8 is a circuit diagram of a control data receiving module according to an embodiment, as shown in fig. 8, the third controlled switch 400 includes a second NPN transistor Q3, and the fourth controlled switch 401 includes a second PNP transistor Q4;

the base electrode of the second NPN triode Q3 is connected with the first switch end of the first controlled switch, and the collector electrode of the second NPN triode Q3 is used for being connected with a logic high level VCC; the emitter of the second NPN triode Q3 is connected with the emitter of the second PNP triode Q4;

the base of the second PNP transistor Q4 is connected to the first switch end of the second controlled switch, and the collector of the second PNP transistor is connected to the logic low level GND through the third voltage division module 402.

As shown in fig. 8, after the controlled terminal B2 of the second controlled switch 101 receives the logic high level sent by the CAN control system, the high-level CAN voltage input/output terminal CANH is at the logic high level, the low-level CAN voltage input/output terminal CANL is at the logic low level, and at this time, the second NPN transistor Q3 and the second PNP transistor Q4 are both in the on state. After the controlled terminal B2 of the second controlled switch 101 receives the logic low level sent by the CAN control system, the high-level CAN voltage input/output terminal CANH is at the logic high level, the low-level CAN voltage input/output terminals CANL are both at the logic low level, and the second NPN triode Q3 is turned off.

In one embodiment, the second NPN transistor Q3 and the second PNP transistor Q4 are both packaged as a pair transistor with SOT 23.

In one embodiment, as shown in fig. 8, the third voltage dividing module 402 includes a third voltage dividing resistor R6. As one embodiment, the third voltage dividing resistor R6 is a resistor with a resistance of 100k Ω.

In one embodiment, as shown in fig. 8, the control data receiving module 11 of an embodiment further includes a fourth voltage dividing resistor R7, a fifth voltage dividing resistor R8, and a sixth voltage dividing resistor R10; the collector of the second NPN transistor Q3 is configured to be coupled to a logic high VCC via a fourth voltage divider resistor R7. The emitter of the second NPN transistor Q3 is connected to the second PNP transistor Q4 through the third voltage dividing resistor R8. An emitter of the second PNP transistor Q4 is connected to the third voltage dividing module 402 through the sixth voltage dividing resistor R10. In one embodiment, the third voltage dividing resistor R7 is a resistor with a resistance of 100 Ω, and the fourth voltage dividing resistor R8 is a resistor with a resistance of 10k Ω.

In one embodiment, as shown in fig. 8, the control data receiving module 11 further includes a first bias resistor R11, a second bias resistor R12, a third bias resistor R13, a fourth bias resistor R14, a fifth bias resistor R15 and a sixth bias resistor R16;

a base electrode of the second NPN triode Q3 is connected to the first switch end K1 of the first controlled switch 100 through a first bias resistor R11, and a base electrode of the second NPN triode Q3 is used to be connected to a logic high level VCC through a third bias resistor R13 and a fifth bias resistor R15 in sequence;

the base of the second PNP transistor Q4 is connected to the first switch terminal K3 of the second controlled switch 101 through the second bias resistor R12; the base electrode of the second PNP triode Q4 is used for being connected to a logic low level GND sequentially through a fourth biasing resistor R14 and a sixth biasing resistor R16;

the common terminal Middle of the third bias resistor R13 and the fifth bias resistor R15 is connected to the common terminal Middle of the fourth bias resistor R14 and the sixth bias resistor R16.

The common terminal Middle plays a role of a bias circuit through the third bias resistor R13, the fourth bias resistor R14, the fifth bias resistor R15 and the sixth bias resistor R16, so that the second NPN triode Q3 and the second PNP triode Q4 can be smoothly conducted. Meanwhile, when the first controlled switch 100 and the second controlled switch 101 are turned off, the high-level CAN voltage input/output terminal CANH and the low-level CAN voltage input/output terminal CANL are in a high-impedance state through the first bias resistor R11, the second bias resistor R12, the third bias resistor R13, the fourth bias resistor R14, the fifth bias resistor R15 and the sixth bias resistor R16.

In one embodiment, the first bias resistor R11 and the second bias resistor R12 are resistors with a resistance of 330k Ω. The third biasing resistor R13, the fourth biasing resistor R14, the fifth biasing resistor R15 and the sixth biasing resistor R16 are resistors with the resistance value of 200k omega.

In one embodiment, as shown in fig. 8, the control data receiving module 11 further includes a first filter capacitor C1 and a second filter capacitor C2;

the base of the second NPN transistor Q3 is configured to be connected to the logic low GND through the first filter capacitor C1, and the base of the second PNP transistor Q4 is configured to be connected to the logic low GND through the second filter capacitor C2.

The first filter capacitor C1 and the second filter capacitor C2 are used for filtering high-frequency spike interference in the circuit. In a preferred embodiment, the first filter capacitor C1 and the second filter capacitor C2 are capacitors having a capacitance of 2.7 pF.

The input end of the received data output module 12 is used for accessing a first logic level or a second logic level; the output end of the received data output module 12 is used for connecting a CAN control system and is used as a received data output end RXD; the received data output module 12 is configured to output a logic low level to the CAN control system according to the first logic level, and the received data output module 12 is configured to output a logic high level to the CAN control system according to the second logic level.

When the CAN control system outputs a logic high level to the controlled terminal B2 of the second controlled switch 101, the received data output module 12 outputs a logic low level to the CAN control system, so as to implement CAN transceiving communication.

In one embodiment, the received data output module 12 may be an integrated circuit chip or a circuit composed of discrete components.

In one embodiment, fig. 9 is a structural diagram of a received data output module according to an embodiment, and as shown in fig. 9, the received data output module 12 includes a fifth controlled switch 500 and a pull-up module 501;

the controlled terminal B5 of the fifth controlled switch 500 is configured to access a first logic level or a second logic level, the first switch terminal K9 of the fifth controlled switch 500 is configured to access a logic high level VCC through the pull-up module 501, and the first switch terminal K9 of the fifth controlled switch 500 is configured to connect to a CAN control system; the second switch terminal K10 of the fifth controlled switch 500 is used for switching on a logic low level GND;

the fifth controlled switch 500 is configured to turn on the first switch terminal K9 and the second switch terminal K10 of the fifth controlled switch 500 when the controlled terminal B5 of the fifth controlled switch 500 is switched to the first logic level.

When the first switch terminal K9 and the second switch terminal K10 are turned on, the first switch terminal K9 is at a logic low level; when the first switch terminal K9 and the second switch terminal K10 are turned off, the first switch terminal K9 is pulled up to a logic high level by the pull-up module 501.

In one embodiment, the fifth controlled switch 500 may be an electronic switch or a semiconductor switch. As a preferred embodiment, the fifth controlled switch 500 is a semiconductor switch, which includes an IGBT switching device, a transistor, and the like.

In one embodiment, fig. 10 is a circuit diagram of a received data output module according to an embodiment, and as shown in fig. 10, the fifth controlled switch 500 includes a third NPN transistor Q5;

a base electrode of the third NPN triode Q5 is used for accessing the first logic level or the second logic level, a collector electrode of the third NPN triode Q5 is used for accessing the logic high level VCC through the pull-up module 501, and a collector electrode of the third NPN triode Q5 is used for connecting the CAN control system; the emitter of the third NPN transistor Q5 is used to switch in a logic low level GND.

As shown in fig. 10, the third NPN transistor Q5 turns on after receiving the first logic level, which is a logic high level, and the collector of the third NPN transistor Q5 is pulled down to a logic low level. The third NPN transistor Q5 turns off after receiving the second logic level, which is a logic low level, and the collector of the third NPN transistor Q5 is pulled up to a logic low level by the pull-up module 501.

In one embodiment, pull-up module 501 includes pull-up resistor R9.

In the CAN transceiver circuit of any of the above embodiments, when the controlled terminal B2 of the second controlled switch 101 is connected to the CAN control system to transmit a logic high level, the first controlled switch 100 and the second controlled switch 101 are both turned on, the first switch terminal K1 of the first controlled switch 100 outputs a logic high level as a high-level CAN voltage, the first switch terminal K3 of the second controlled switch 101 outputs a logic low level as a CAN low voltage, and the output terminal of the received data output module 12 outputs a logic low level signal to the CAN control system. Based on this, the complete transceiving function between the CAN bus network and the CAN control system is realized through the control data sending module 10, the control data receiving module 11 and the received data output module 12. Further, since the control data sending module 10 employs discrete modules such as the first controlled switch 100 and the second controlled switch 101, it is convenient to replace, and adjust the driving capability of the logic high level and the logic low level output to the CAN bus network to meet the requirements of different application environments.

The embodiment of the utility model provides a CAN communication system is still provided.

Fig. 11 is a structural diagram of a CAN communication system according to an embodiment, and as shown in fig. 11, the CAN communication system according to an embodiment includes a CAN control system 1000, a CAN bus network 1001, and a CAN transceiver circuit 1002 according to any of the embodiments.

As shown in fig. 11, a transmission data input terminal TXD and a reception data output terminal RXD in the CAN transceiver circuit 1003 are respectively connected to the CAN control system 1000; a high-level CAN voltage input/output terminal CANH in the CAN transceiver circuit 1003 is connected to one line in the CAN bus network 1001, and a low-level CAN voltage input/output terminal CANL in the CAN transceiver circuit 1003 is connected to the other line in the CAN bus network 1001. Based on this, a complete CAN communication system is constructed.

In the CAN communication system, when the controlled terminal B2 of the second controlled switch 101 is connected to the CAN control system to transmit a logic high level, the first controlled switch 100 and the second controlled switch 101 are both turned on, the first switch terminal K1 of the first controlled switch 100 outputs a logic high level as a high-level CAN voltage, the first switch terminal K3 of the second controlled switch 101 outputs a logic low level as a CAN low voltage, and the output terminal of the received data output module 12 outputs a logic low level signal to the CAN control system 1000. Based on this, a complete transceiving function between the CAN bus network 1001 and the CAN control system 1000 is realized by the control data transmitting module 10, the control data receiving module 11, and the received data outputting module 12. Further, since the control data sending module 10 employs discrete modules such as the first controlled switch 100 and the second controlled switch 101, it is convenient to replace, and adjust the driving capability of the logic high level and the logic low level output to the CAN bus network to meet the requirements of different application environments.

The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above examples only represent some embodiments of the present invention, and the description thereof is more specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims

1. A CAN transceiver circuit is characterized by comprising a control data transmitting module, a control data receiving module and a received data output module;

the control data sending module comprises a first controlled switch and a second controlled switch; the first switch end of the first controlled switch is used for connecting a CAN bus network and is used as a high-level CAN voltage input/output end; the second switch end of the first controlled switch is used for accessing a logic high level; the controlled end of the first controlled switch is connected with the first switch end of the second controlled switch; the first switch end of the second controlled switch is also used for connecting a CAN bus network and is used as a low-level CAN voltage input/output end; the second switch end of the second controlled switch is used for switching in a logic low level; the controlled end of the second controlled switch is used for connecting a CAN control system and is used as a data sending input end; the first controlled switch is used for conducting a first switch end and a second switch end of the first controlled switch when a controlled end of the first controlled switch is connected to a logic low level; the second controlled switch is used for conducting a first switch end and a second switch end of the second controlled switch when a controlled end of the second controlled switch is connected to a logic high level;

a first receiving end of the control data receiving module is connected with a first switch end of the first controlled switch, and a second receiving end of the control data receiving module is connected with a first switch end of the second controlled switch; the control data receiving module is used for outputting a first logic level to the received data output module when the controlled end of the second controlled switch is switched into a logic high level; the control data receiving module is further configured to output a second logic level to the received data output module when the controlled end of the second controlled switch is switched into a logic low level;

the input end of the received data output module is used for accessing the first logic level or the second logic level; the output end of the received data output module is used for being connected with the CAN control system and used as a received data output end; the received data output module is used for outputting a logic low level to the CAN control system according to the first logic level, and the received data output module is used for outputting a logic high level to the CAN control system according to the second logic level.

2. The CAN transceiver circuit of claim 1, wherein the control data transmission module further comprises a first isolation unit and a second isolation unit;

the first switch end of the first controlled switch is used for being connected with a CAN bus network through the first isolation unit; and the first switch end of the second controlled switch is used for being connected with the CAN bus network through the second isolation unit.

3. The CAN transceiver circuit of claim 2, wherein the first isolation unit comprises a first diode and the second isolation unit comprises a second diode;

a first switch end of the first controlled switch is connected with the anode of the first diode, and the cathode of the first diode is used for connecting a CAN bus network;

and the first switch end of the second controlled switch is connected with the cathode of the second diode, and the anode of the second diode is used for connecting a CAN bus network.

4. The CAN transceiver circuit of claim 1, wherein the control data transmission module further comprises a first voltage division module and a second voltage division module;

the controlled end of the first controlled switch is used for accessing a logic high level through the first voltage division module; and the controlled end of the first controlled switch is also used for being connected with the first switch end of the second controlled switch through the second voltage division module.

5. The CAN transceiver circuit of claim 1, wherein the first controlled switch and the second controlled switch each comprise a semiconductor switch.

6. The CAN transceiver circuit of claim 5, wherein the first controlled switch comprises a first PNP transistor; the second controlled switch comprises a first NPN triode;

the collector of the first PNP triode is used for being connected with a CAN bus network and used as a high-level CAN voltage input/output end; the emitter of the first PNP triode is used for accessing a logic high level; the base electrode of the first PNP triode is connected with the collector electrode of the first NPN triode; the collector of the first NPN triode is also used for connecting a CAN bus network and is used as a low-level CAN voltage input/output end; an emitter of the first NPN triode is used for accessing a logic low level; and the base electrode of the first NPN triode is used for being connected with a CAN control system and used as a data sending input end.

7. The CAN transceiver circuit of claim 1, wherein the control data receiving module comprises a third controlled switch, a fourth controlled switch, and a third voltage division module;

the controlled end of the third controlled switch is connected with the first switch end of the first controlled switch, and the first switch end of the third controlled switch is used for accessing a logic high level; the second switch end of the third controlled switch is connected with the second switch end of the fourth controlled switch; the third controlled switch is used for conducting a first switch end and a second switch end of the third controlled switch when a controlled end of the third controlled switch is connected to a logic high level;

the controlled end of the fourth controlled switch is connected with the first switch end of the second controlled switch, and the first switch end of the fourth controlled switch is used for accessing a logic low level through the third voltage division module; the fourth controlled switch is used for conducting the first switch end and the second switch end of the fourth controlled switch when the controlled end of the fourth controlled switch is switched into a logic low level.

8. The CAN transceiver circuit of claim 7, wherein the third controlled switch and the fourth controlled switch each comprise a semiconductor switch.

9. The CAN transceiver circuit of claim 8, wherein the third controlled switch comprises a second NPN transistor, and the fourth controlled switch comprises a second PNP transistor;

a base electrode of the second NPN triode is connected with a first switch end of the first controlled switch, and a collector electrode of the second NPN triode is used for accessing a logic high level; the emitter of the second NPN triode is connected with the emitter of the second PNP triode;

and the base electrode of the second PNP triode is connected with the first switch end of the second controlled switch, and the collector electrode of the second PNP triode is used for being connected into a logic low level through the third voltage division module.

10. The CAN transceiver circuit of claim 9, wherein the control data receiving module further comprises a first bias resistor, a second bias resistor, a third bias resistor, a fourth bias resistor, a fifth bias resistor, and a sixth bias resistor;

the base electrode of the second NPN triode is connected with the first switch end of the first controlled switch through the first biasing resistor, and the base electrode of the second NPN triode is used for being connected with a logic high level through the third biasing resistor and the fifth biasing resistor in sequence;

the base electrode of the second PNP triode is connected with the first switch end of the second controlled switch through the second bias resistor; the base electrode of the second PNP triode is used for being connected with a logic low level sequentially through the fourth biasing resistor and the sixth biasing resistor;

11. The CAN transceiver circuit of claim 9, wherein the control data receiving module further comprises a first filter capacitor and a second filter capacitor;

the base electrode of the second NPN triode is used for being connected into a logic low level through the first filter capacitor, and the base electrode of the second PNP triode is used for being connected into the logic low level through the second filter capacitor.

12. The CAN transceiver circuit of claim 1, wherein the receive data output module comprises a fifth controlled switch and a pull-up module;

the controlled end of the fifth controlled switch is used for accessing the first logic level or the second logic level, the first switch end of the fifth controlled switch is used for accessing a logic high level through the pull-up module, and the first switch end of the fifth controlled switch is used for connecting the CAN control system; the second switch end of the fifth controlled switch is used for switching in a logic low level;

13. The CAN transceiver circuit of claim 12, wherein the fifth controlled switch comprises a semiconductor switch.

14. The CAN transceiver circuit of claim 13, wherein the fifth controlled switch comprises a third NPN transistor;

a base electrode of the third NPN triode is used for being connected into the first logic level or the second logic level, a collector electrode of the third NPN triode is used for being connected into a logic high level through the pull-up module, and the collector electrode of the third NPN triode is used for being connected with the CAN control system; and the emitter of the third NPN triode is used for switching in a logic low level.

15. A CAN communication system comprising a CAN control system, a CAN bus network, and the CAN transceiver circuit of any one of claims 1 to 14.