CAN transceiver circuit and CAN communication system

Abstract

The present invention relates to a CAN transceiver circuit and a CAN communication system. When the controlled end of the second controlled switch is connected to a CAN control system and transmits a logic high level, both the first and second controlled switches are turned on. The first switch end of the first controlled switch outputs a logic high level as a high-level CAN voltage, while the first switch end of the second controlled switch outputs a logic low level as a low-level CAN voltage. Simultaneously, the output end of a received data output module outputs a logic low signal to the CAN control system. Based on this, a complete transceiver function between a CAN bus network and a CAN control system is implemented through a control data transmission module, a control data reception module, and a received data output module. Furthermore, because the control data transmission module utilizes discrete modules, such as the first and second controlled switches, it can be easily replaced, and the driving capability of the logic high and logic low levels output to the CAN bus network can be adjusted to meet the needs of different application environments.

Description

Technical Field

[0001] The present invention relates to the technical field of bus control, and in particular to a CAN transceiver circuit and a CAN communication system. Background Art

[0002] The CAN (Controller Area Network) bus is a serial communication network that effectively supports distributed and real-time control and is currently one of the most widely used fieldbuses internationally. The CAN bus generally consists of a CAN control system, a CAN transceiver, and a CAN bus network. The CAN transceiver, as the core component of the CAN bus, is used to receive and transmit data under the control of the CAN control system and serves as a bridge between the CAN control system and the CAN bus network.

[0003] The traditional method of building a CAN transceiver typically involves directly using a general-purpose CAN transceiver chip. The ports that implement these functions primarily include: transmit data input TXD, receive data output RXD, high-level CAN voltage input / output CANH, and low-level CAN voltage input / output CANL. The CAN transceiver chip's transmit data input TXD and receive data output RXD are both used to connect to the CAN control system, while the CAN transceiver chip's high-level CAN voltage input / output CANH and low-level CAN voltage input / output CANL are both used to connect to the CAN bus network. The high-level CAN voltage input / output CANH connects to one type of line in the CAN bus network, while the high-level CAN voltage input / output CANH connects to another type of line in the CAN bus network. Based on the operating logic between the transmit data input TXD, receive data output RXD, high-level CAN voltage input / output CANH, and low-level CAN voltage input / output CANL, complete CAN bus transmission and reception control is implemented.

[0004] However, the performance parameters and indicators of CAN transceiver chips are constrained by chip design, such as a fixed number of connected devices or a fixed degree of isolation. In other words, the indicators are fixed and cannot be adjusted, making it difficult to meet the needs of complex application environments. Summary of the Invention

[0005] Based on this, it is necessary to provide a CAN transceiver circuit and a CAN communication system, as the performance parameters and indicators of the CAN transceiver chip are constrained by the chip design, the indicators are fixed and cannot be adjusted, and it is difficult to meet the application needs in complex application environments.

[0006] A CAN transceiver circuit includes a control data sending module, a control data receiving module and a received data output module;

[0007] The control data transmission module includes a first controlled switch and a second controlled switch; the first switch end of the first controlled switch is used to connect to the CAN bus network and serve as a high-level CAN voltage input / output end; the second switch end of the first controlled switch is used to access a logic high level; the controlled end of the first controlled switch is connected to the first switch end of the second controlled switch; the first switch end of the second controlled switch is also used to connect to the CAN bus network and serve as a low-level CAN voltage input / output end; the second switch end of the second controlled switch is used to access a logic low level; the controlled end of the second controlled switch is used to connect to the CAN control system and serve as a data transmission input end; wherein, the first controlled switch is used to connect the first switch end and the second switch end of the first controlled switch when the controlled end of the first controlled switch is connected to a logic low level; and the second controlled switch is used to connect the first switch end and the second switch end of the second controlled switch when the controlled end of the second controlled switch is connected to a logic high level.

[0008] The first receiving end of the control data receiving module is connected to the first switch end of the first controlled switch, and the second receiving end of the control data receiving module is connected to the first switch end of the second controlled switch; wherein the control data receiving module is configured to output a first logic level to the received data output module when the first receiving end is connected to a logic high level and the second receiving end is connected to a logic low level; and 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 connected to a logic low level;

[0009] The input end of the received data output module is used to access the first logic level or the second logic level; the output end of the received data output module is used to connect to the CAN control system as the received data output end; the received data output module is used to output a logic low level to the CAN control system according to the first logic level, and the received data output module is used to output a logic high level to the CAN control system according to the second logic level.

[0010] In the aforementioned CAN transceiver circuit, when the controlled end of the second controlled switch is connected to the CAN control system and transmits a logic-high signal, both the first and second controlled switches are turned on. The first switch end of the first controlled switch outputs a logic-high signal as a high-level CAN voltage, while the first switch end of the second controlled switch outputs a logic-low signal as a low-level CAN voltage. Simultaneously, the output end of the received data output module outputs a logic-low signal to the CAN control system. Thus, the control data transmission module, the control data reception module, and the received data output module implement complete transceiver functionality between the CAN bus network and the CAN control system. Furthermore, because the control data transmission module utilizes discrete modules, namely the first and second controlled switches, it can be easily replaced, allowing the drive capability of the logic-high and logic-low signals output to the CAN bus network to be adjusted to suit the needs of different application environments.

[0011] In one embodiment, the control data sending module further includes a first isolation unit and a second isolation unit;

[0012] The first switch end of the first controlled switch is used to connect to the CAN bus network through the first isolation unit; the first switch end of the second controlled switch is used to connect to the CAN bus network through the second isolation unit.

[0013] In one embodiment, the first isolation module includes a first diode, and the second isolation module includes a second diode;

[0014] The first switch end of the first controlled switch is connected to the anode of the first diode, and the cathode of the first diode is used to connect to the CAN bus network;

[0015] The first switch end of the second controlled switch is connected to the cathode of the second diode, and the anode of the second diode is used to connect to the CAN bus network.

[0016] In one embodiment, the control data sending module further includes a first voltage dividing module and a second voltage dividing module;

[0017] The controlled end of the first controlled switch is used to access a logic high level through a first voltage divider module; the controlled end of the first controlled switch is also used to connect to a first switch end of a second controlled switch through a second voltage divider module.

[0018] In one embodiment, the first controlled switch and the second controlled switch both include semiconductor switches.

[0019] In one embodiment, the first controlled switch includes a first PNP transistor; the second controlled switch includes a first NPN transistor;

[0020] The collector of the first PNP transistor is used to connect to the CAN bus network as a high-level CAN voltage input / output terminal; the emitter of the first PNP transistor is used to access a logic high level; the base of the first PNP transistor is connected to the collector of the first NPN transistor; the collector of the first NPN transistor is also used to connect to the CAN bus network as a low-level CAN voltage input / output terminal; the emitter of the first NPN transistor is used to access a logic low level; the base of the first NPN transistor is used to connect to the CAN control system as a sending data input terminal.

[0021] In one embodiment, the control data receiving module includes a third controlled switch, a fourth controlled switch and a third voltage dividing module;

[0022] The controlled end of the third controlled switch is connected to the first switch end of the first controlled switch, and the first switch end of the third controlled switch is used to connect to a logic high level; the second switch end of the third controlled switch is connected to the second switch end of the fourth controlled switch; wherein the third controlled switch is used to conduct the first switch end and the second switch end of the third controlled switch when the controlled end of the third controlled switch is connected to a logic high level;

[0023] The controlled end of the fourth controlled switch is connected to the first switch end of the second controlled switch, and the first switch end of the fourth controlled switch is used to connect to the logic low level through the third voltage divider module; wherein the fourth controlled switch is used to connect the first switch end and the second switch end of the fourth controlled switch when the controlled end of the fourth controlled switch is connected to the logic low level

[0024] In one embodiment, the third controlled switch and the fourth controlled switch both include semiconductor switches.

[0025] In one embodiment, the third controlled switch includes a second NPN transistor, and the fourth controlled switch includes a second PNP transistor;

[0026] The base of the second NPN transistor is connected to the first switch terminal of the first controlled switch, and the collector of the second NPN transistor is used to access the logic high level; the emitter of the second NPN transistor is connected to the emitter of the second PNP transistor;

[0027] The base of the second PNP transistor is connected to the first switch end of the second controlled switch, and the collector of the second PNP transistor is used to access a logic low level through the third voltage divider module.

[0028] In one embodiment, the control data receiving module further includes 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;

[0029] The base of the second NPN transistor is connected to the first switch terminal of the first controlled switch through the first bias resistor, and the base of the second NPN transistor is used to sequentially access the logic high level through the third bias resistor and the fifth bias resistor;

[0030] The base of the second PNP transistor is connected to the first switch terminal of the second controlled switch through the second bias resistor; the base of the second PNP transistor is used to sequentially access the logic low level through the fourth bias resistor and the sixth bias resistor;

[0031] A common end of the third bias resistor and the fifth bias resistor is connected to a common end of the fourth bias resistor and the sixth bias resistor.

[0032] In one embodiment, the control data receiving module further includes a first filter capacitor and a second filter capacitor;

[0033] The base of the second NPN transistor is used to access the logic low level through the first filter capacitor, and the base of the second PNP transistor is used to access the logic low level through the second filter capacitor.

[0034] In one embodiment, the received data output module includes a fifth controlled switch and a pull-up module;

[0035] The controlled end of the fifth controlled switch is used to access the first logic level or the second logic level, the first switch end of the fifth controlled switch is used to access the logic high level through the pull-up module, and the first switch end of the fifth controlled switch is used to connect to the CAN control system; the second switch end of the fifth controlled switch is used to access the logic low level;

[0036] The fifth controlled switch is configured to turn on 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.

[0037] In one embodiment, the fifth controlled switch comprises a semiconductor switch.

[0038] In one embodiment, the fifth controlled switch includes a third NPN transistor;

[0039] The base of the third NPN transistor is used to access the first logic level or the second logic level, the collector of the third NPN transistor is used to access the logic high level through the pull-up module, and the collector of the third NPN transistor is used to connect to the CAN control system; the emitter of the third NPN transistor is used to access the logic low level.

[0040] A CAN communication system includes a CAN control system, a CAN bus network, and a CAN transceiver circuit according to any one of the above embodiments.

[0041] In the aforementioned CAN communication system, when the controlled end of the second controlled switch is connected to the CAN control system and transmits a logic-high signal, both the first and second controlled switches are turned on. The first switch end of the first controlled switch outputs a logic-high signal as a high-level CAN voltage, while the first switch end of the second controlled switch outputs a logic-low signal as a low-level CAN voltage. Simultaneously, the output end of the received data output module outputs a logic-low signal to the CAN control system. Consequently, the control data transmission module, the control data reception module, and the received data output module implement complete transceiver functionality between the CAN bus network and the CAN control system. Furthermore, because the control data transmission module utilizes discrete modules, namely the first and second controlled switches, it can be easily replaced, allowing the drive capability of the logic-high and logic-low signals output to the CAN bus network to be adjusted to suit the needs of different application environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 1 is a structural diagram of a CAN transceiver circuit module according to an embodiment of the present invention;

[0043] Figure 2 A circuit diagram of a control data sending module according to one embodiment;

[0044] Figure 3 A structural diagram of a control data sending module in another embodiment;

[0045] Figure 4 A circuit diagram of a control data sending module in another embodiment;

[0046] Figure 5 This is a structural diagram of a control data sending module according to another embodiment;

[0047] Figure 6 A circuit diagram of a control data sending module according to another embodiment;

[0048] Figure 7 This is a structural diagram of a control data receiving module according to one embodiment;

[0049] Figure 8 A circuit diagram of a control data receiving module according to one embodiment;

[0050] Figure 9 A structural diagram of a received data output module according to an embodiment of the present invention;

[0051] Figure 10 A circuit diagram of a receiving data output module according to an embodiment of the present invention;

[0052] Figure 11 This is a diagram of the CAN communication system architecture according to one embodiment. DETAILED DESCRIPTION

[0053] In order to better understand the purpose, technical solutions and technical effects of the present invention, the present invention is further explained below with reference to the accompanying drawings and embodiments. It is also stated that the embodiments described below are only used to illustrate the present invention and are not intended to limit the present invention.

[0054] An embodiment of the present invention provides a CAN transceiver circuit.

[0055] Figure 1 FIG. 1 is a block diagram of a CAN transceiver circuit module according to an embodiment of the present invention. Figure 1 As shown, a CAN transceiver circuit of one embodiment includes a control data sending module 10, a control data receiving module 11 and a received data output module 12;

[0056] The control data sending 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 to connect to the CAN bus network and serve as a high-level CAN voltage input / output terminal CANH; the second switch terminal K2 of the first controlled switch 100 is used to access a logic high level; the controlled terminal B1 of the first controlled switch 100 is connected to the first switch terminal K3 of the second controlled switch 101; the first switch terminal K3 of the second controlled switch 101 is also used to connect to the CAN bus network and serve as a low-level CAN voltage input / output terminal CANL; The second switch terminal K4 of the second controlled switch 101 is used to connect to a logic low level; the controlled terminal B2 of the second controlled switch 101 is used to connect to the CAN control system and serve as the transmit data input terminal TXD; wherein, the first controlled switch 100 is used to connect 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 connected to a logic low level; the second controlled switch 101 is used to connect 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 connected to a logic high level;

[0057] The controlled terminal B2 of the second controlled switch 101 serves as a transmit data input terminal TXD, connected to a CAN control system to receive control data sent by the CAN control system. Conventional CAN control systems send control data that includes high and low levels. In this embodiment, the high level sent by the CAN control system corresponds to a logical high level, and the low level sent by the CAN control system corresponds to a logical low level.

[0058] For ease of explanation, this embodiment defines a voltage level above a set threshold as a logic high level, and a ground signal as a logic low level. It should be noted that the logic high and logic low levels may also be selected to have other specific level signals, provided that they satisfy the operating relationships of the modules in this embodiment, and are not limited to the above-mentioned limitations.

[0059] In one embodiment, when the CAN control system transmits a logic high level, the controlled terminal B1 of the second controlled switch 101 receives the logic high level, and its first switch terminal K3 and second switch terminal K4 are conductive, causing the logic low level to be transmitted to the controlled terminal B1 of the first controlled switch 100, and the first switch terminal K1 and second switch terminal K2 are conductive. 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, implementing serial differential transmission of the CAN bus network.

[0060] In one embodiment, when the CAN control system transmits a logic low, the controlled terminal B1 of the second controlled switch 101 receives the logic low, disconnecting the first switch terminal K3 and the second switch terminal K4, thereby also disconnecting the first switch terminal K1 and the second switch terminal K2. At this point, based on the characteristics of the control data receiving module 11, the high-level CAN voltage input / output terminal CANH is suspended or in a high-impedance state, and the low-level CAN voltage input / output terminal CANL is suspended or in a high-impedance state, forming another communication state in the CAN bus network.

[0061] Based on this, the control data sending module 10 provides a signal level to the CAN bus network in the form of a logic level 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.

[0062] It's important to note that in traditional CAN transceiver chips, the components are highly integrated, resulting in fixed chip parameters. Specifically, the chip's driving capability for the CAN bus network is fixed, leading to a fixed number of connected devices. In this embodiment, the first controlled switch 100 and the second controlled switch 101 are discrete components or modules. Users can change the parameters of the control data transmission module 10 by replacing the first controlled switch 100 or the second controlled switch 101, thereby changing the control data transmission module 10's driving capability for the CAN bus network.

[0063] In one embodiment, the first controlled switch 100 and the second controlled switch 101 can be electronic switches or semiconductor switches. As a preferred embodiment, the first controlled switch 100 and the second controlled switch 101 are both semiconductor switches, including IGBT switching devices and transistors.

[0064] In one embodiment, Figure 2 FIG. 1 is a circuit diagram of a control data sending module according to an embodiment of the present invention. Figure 2 As shown, the first controlled switch 100 includes a first PNP transistor Q1; the second controlled switch 101 includes a first NPN transistor Q2;

[0065] The collector of the first PNP transistor Q1 is used to connect to the CAN bus network and serve as the high-level CAN voltage input / output terminal CANH; the emitter of the first PNP transistor Q1 is used to access the logic high level VCC; the base of the first PNP transistor Q1 is connected to the collector of the first NPN transistor Q1; the collector of the first NPN transistor Q1 is also used to connect to the CAN bus network and serve as the low-level CAN voltage input / output terminal CANL; the emitter of the first NPN transistor Q2 is used to access the logic low level GND; the base of the first NPN transistor Q2 is used to connect to the CAN control system and serve as the sending data input terminal.

[0066] like Figure 2 As shown, after the base of the first NPN transistor Q2 receives a logic high level from 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 a logic low level, turning on the first PNP transistor Q1. 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.

[0067] As a preferred implementation, 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.

[0068] In one embodiment, Figure 2 As shown, the control data sending 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 via the first current limiting resistor R1 .

[0069] In one embodiment, Figure 2 As shown, the control data sending module 10 further includes a first driving resistor R2 and a second driving resistor R3;

[0070] The collector of the first PNP transistor Q1 is connected to the CAN bus network via a first driving resistor R2 , and the collector of the first NPN transistor Q2 is connected to the CAN bus network via a second driving resistor R3 .

[0071] The first drive resistor R2 improves the level driving capability of the collector of the first PNP transistor Q1, while the second drive resistor R3 improves the level driving capability of the collector of the first NPN transistor Q2. As a preferred embodiment, both the first drive resistor R2 and the second drive resistor R3 are 1 kΩ resistors to effectively improve the level driving capability.

[0072] In one embodiment, Figure 3 FIG. 1 is a structural diagram of a control data sending module in another embodiment, as shown in FIG. Figure 3 As shown, the control data sending module 10 of another embodiment further includes a first isolation unit 200 and a second isolation unit 201;

[0073] The first switch terminal K1 of the first controlled switch 100 is used to connect to the CAN bus network through the first isolation unit 200 ; the first switch terminal of the second controlled switch 101 is used to connect to the CAN bus network through the second isolation unit 201 .

[0074] The first isolation unit 200 is used to improve the isolation of the high-level CAN voltage input / output terminal CANH, and the second isolation unit 201 is used 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 can be implemented as separate isolation modules or isolation components to facilitate replacement and adjustment of the isolation between the high-level CAN voltage input / output terminal CANH and the low-level CAN voltage input / output terminal CANL.

[0075] In one embodiment, Figure 4 FIG. 1 is a circuit diagram of a control data sending module in another embodiment, as shown in FIG. Figure 4 As shown, the first isolation module 200 includes a first diode D1, and the second isolation module 201 includes a second diode D2;

[0076] The first switch terminal K1 of the first controlled switch 100 is connected to the anode of the first diode D1, and the cathode of the first diode D1 is used to connect to the CAN bus network;

[0077] The first switch end 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 to connect to the CAN bus network.

[0078] The first diode D1 is used to isolate the high-level CAN voltage input / output terminal CANH, and the second diode D2 is used to isolate the low-level CAN voltage input / output terminal CANL. In one embodiment, both the first diode D1 and the second diode D2 may be diodes with high reverse withstand voltage 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.

[0079] In one embodiment, Figure 5 FIG. 1 is a structural diagram of a control data sending module according to another embodiment of the present invention. Figure 5 As shown, the control data sending module 10 of another embodiment further includes a first voltage dividing module 300 and a second voltage dividing module 301;

[0080] The controlled terminal B1 of the first controlled switch 100 is used to access the logic high level VCC through the first voltage divider module 300 ; the controlled terminal B1 of the first controlled switch 100 is also used to connect to the first switch terminal K3 of the second controlled switch 101 through the second voltage divider module 301 .

[0081] The first voltage divider module 300 and the second voltage divider module 301 are used to adjust the voltage difference between a logic high level and a logic low level, thereby changing the voltage level of the controlled terminal B1 of the first controlled switch 100. Simultaneously, when the first switch terminal K3 and the second switch terminal K4 of the second controlled switch 101 are conductive, they function as a bias circuit, thereby conductively connecting the first switch terminal K1 and the second switch terminal K2 of the first controlled switch 100.

[0082] In one embodiment, Figure 6 FIG. 1 is a circuit diagram of a control data sending module in another embodiment, as shown in FIG. Figure 6 As shown, 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.

[0083] In one embodiment, the first voltage-dividing resistor R4 and the second voltage-dividing resistor R5 are both 100 kΩ resistors.

[0084] The 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 the 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 output module 12 when the first receiving end is connected to a logic high level and the second receiving end is connected to a logic low level. 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 end B2 of the second controlled switch 101 is connected to a logic low level GND.

[0085] 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 control data receiving module 11 is at a logic high level, the second receiving terminal of the control data receiving module 11 is at a logic low level, and the control data receiving module 11 outputs a 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 control data receiving module 11 is in a floating or high-impedance state, and the second receiving terminal of the control data receiving module 11 is in a floating or high-impedance state, which is equivalent to both the first receiving terminal and the second receiving terminal being at a logic low level, and the control data receiving module 11 outputs a second logic level to the received data output module 12.

[0086] In one embodiment, the control data receiving module 11 may be implemented as an integrated circuit chip or a circuit composed of discrete components.

[0087] In one embodiment, Figure 7 FIG. 1 is a structural diagram of a control data receiving module according to an embodiment of the present invention. Figure 7 As shown, the control data receiving module 11 of one embodiment includes a third controlled switch 400, a fourth controlled switch 401 and a third voltage dividing module 402;

[0088] 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 to be connected to the 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; wherein, the third controlled switch 400 is configured to conduct 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;

[0089] 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 used to be connected to the logic low level GND through the third voltage divider module 402. The fourth controlled switch 401 is used to conduct 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.

[0090] After the controlled terminal B2 of the second controlled switch 101 receives a logic high signal from the CAN control system, 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. At this point, 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 divider module 402, the logic high level is output as the first logic level to the input terminal of the received data output module 12. After the controlled terminal B2 of the second controlled switch 101 receives a logic low signal from the CAN control system, 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 equivalent to a logic low level. The first switch terminal K5 and the second switch terminal K6 are turned off, and the third voltage divider module 402 outputs the logic low level as the second logic level to the input terminal of the received data output module 12.

[0091] In this embodiment, the third controlled switch 400 and the fourth controlled switch 401 are discrete components or discrete modules. The user can change the parameters of the control data sending module 10 by replacing the third controlled switch 400 or the fourth controlled switch 401 to change the driving capability of the control data sending module 10 on the CAN bus network.

[0092] In one embodiment, the third controlled switch 400 and the fourth controlled switch 401 can be electronic switches or semiconductor switches. As a preferred embodiment, the third controlled switch 400 and the fourth controlled switch 401 are both semiconductor switches, including IGBT switching devices and transistors.

[0093] In one embodiment, Figure 8 FIG. 1 is a circuit diagram of a control data receiving module according to an embodiment of the present invention. Figure 8 As shown, the third controlled switch 400 includes a second NPN transistor Q3, and the fourth controlled switch 401 includes a second PNP transistor Q4;

[0094] The base of the second NPN transistor Q3 is connected to the first switch terminal of the first controlled switch, and the collector of the second NPN transistor Q3 is used to access the logic high level VCC; the emitter of the second NPN transistor Q3 is connected to the emitter of the second PNP transistor Q4;

[0095] The base of the second PNP transistor Q4 is connected to the first switch terminal of the second controlled switch, and the collector of the second PNP transistor is used to access the logic low level GND through the third voltage divider module 402 .

[0096] like Figure 8 As shown, after the controlled end B2 of the second controlled switch 101 receives a logic high level sent by the CAN control system, 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. At this time, the second NPN transistor Q3 and the second PNP transistor Q4 are both in the on state. After the controlled end B2 of the second controlled switch 101 receives a logic low level sent by the CAN control system, 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 equivalent to being at a logic low level, and the second NPN transistor Q3 is turned off.

[0097] In one embodiment, the second NPN transistor Q3 and the second PNP transistor Q4 are both packaged in SOT23.

[0098] In one embodiment, Figure 8As shown, 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 100 kΩ.

[0099] In one embodiment, Figure 8 As shown, in one embodiment, the control data receiving module 11 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 connected to the logic high voltage VCC via the fourth voltage-dividing resistor R7. The emitter of the second NPN transistor Q3 is connected to the second PNP transistor Q4 via the third voltage-dividing resistor R8. The emitter of the second PNP transistor Q4 is connected to the third voltage-dividing module 402 via the sixth voltage-dividing resistor R10. In one embodiment, the third voltage-dividing resistor R7 is a 100Ω resistor, and the fourth voltage-dividing resistor R8 is a 10kΩ resistor.

[0100] In one embodiment, Figure 8 As shown, 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;

[0101] The base of the second NPN transistor Q3 is connected to the first switch terminal K1 of the first controlled switch 100 through the first bias resistor R11, and the base of the second NPN transistor Q3 is used to connect to the logic high level VCC through the third bias resistor R13 and the fifth bias resistor R15 in sequence;

[0102] 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 of the second PNP transistor Q4 is used to connect to the logic low level GND through the fourth bias resistor R14 and the sixth bias resistor R16 in sequence;

[0103] A common end Middle of the third bias resistor R13 and the fifth bias resistor R15 is connected to a common end Middle of the fourth bias resistor R14 and the sixth bias resistor R16 .

[0104] The common terminal Middle functions as 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, enabling smooth conduction of the second NPN transistor Q3 and the second PNP transistor Q4. Furthermore, 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 placed 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.

[0105] In one embodiment, the first bias resistor R11 and the second bias resistor R12 are both 330 kΩ resistors, and the third bias resistor R13, the fourth bias resistor R14, the fifth bias resistor R15, and the sixth bias resistor R16 are both 200 kΩ resistors.

[0106] In one embodiment, Figure 8 As shown, the control data receiving module 11 further includes a first filter capacitor C1 and a second filter capacitor C2;

[0107] The base of the second NPN transistor Q3 is used to access the logic low level GND through the first filter capacitor C1 , and the base of the second PNP transistor Q4 is used to access the logic low level GND through the second filter capacitor C2 .

[0108] The first filter capacitor C1 and the second filter capacitor C2 are used to filter out high-frequency spike interference in the circuit. As a preferred embodiment, the first filter capacitor C1 and the second filter capacitor C2 are both 2.7 pF capacitors.

[0109] The input end of the received data output module 12 is used to access the first logic level or the second logic level; the output end of the received data output module 12 is used to connect to the CAN control system as the received data output end RXD; the received data output module 12 is used 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 used to output a logic high level to the CAN control system according to the second logic level.

[0110] 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, thereby realizing CAN transceiver communication.

[0111] In one embodiment, the received data output module 12 can be implemented as an integrated circuit chip or a circuit composed of discrete components.

[0112] In one embodiment, Figure 9 FIG. 1 is a structural diagram of a receiving data output module according to an embodiment of the present invention. Figure 9 As shown, the received data output module 12 includes a fifth controlled switch 500 and a pull-up module 501;

[0113] The controlled terminal B5 of the fifth controlled switch 500 is used to connect to the first logic level or the second logic level. The first switch terminal K9 of the fifth controlled switch 500 is used to connect to the logic high level VCC through the pull-up module 501. The first switch terminal K9 of the fifth controlled switch 500 is used to connect to the CAN control system. The second switch terminal K10 of the fifth controlled switch 500 is used to connect to the logic low level GND.

[0114] 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 connected to the first logic level.

[0115] 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 .

[0116] In one embodiment, the fifth controlled switch 500 can be an electronic switch or a semiconductor switch. As a preferred embodiment, the fifth controlled switch 500 is a semiconductor switch, including an IGBT switch device and a transistor.

[0117] In one embodiment, Figure 10 FIG. 1 is a circuit diagram of a receiving data output module according to an embodiment of the present invention, Figure 10 As shown, the fifth controlled switch 500 includes a third NPN transistor Q5;

[0118] The base of the third NPN transistor Q5 is used to access the first logic level or the second logic level, the collector of the third NPN transistor Q5 is used to access the logic high level VCC through the pull-up module 501, and the collector of the third NPN transistor Q5 is used to connect to the CAN control system; the emitter of the third NPN transistor Q5 is used to access the logic low level GND.

[0119] like Figure 10 As shown, the third NPN transistor Q5 is turned on after receiving the first logic level of the logic high level, and the collector of the third NPN transistor Q5 is pulled down to the logic low level. The third NPN transistor Q5 is turned off after receiving the second logic level of the logic low level, and the collector of the third NPN transistor Q5 is pulled up to the logic low level by the pull-up module 501.

[0120] In one embodiment, the pull-up module 501 includes a pull-up resistor R9.

[0121] In any of the above-described CAN transceiver circuits, when the controlled terminal B2 of the second controlled switch 101 is connected to the CAN control system and transmits a logic high, both the first controlled switch 100 and the second controlled switch 101 are turned on. The first switch terminal K1 of the first controlled switch 100 outputs a logic high as a high-level CAN voltage, and the first switch terminal K3 of the second controlled switch 101 outputs a logic low as a low-level CAN voltage. Simultaneously, the output terminal of the received data output module 12 outputs a logic low signal to the CAN control system. Thus, the control data transmitting module 10, the control data receiving module 11, and the received data output module 12 implement complete transceiver functionality between the CAN bus network and the CAN control system. Furthermore, because the control data transmitting module 10 utilizes discrete modules such as the first controlled switch 100 and the second controlled switch 101, it can be easily replaced and the drive capability of the logic high and logic low levels output to the CAN bus network can be adjusted to meet the needs of different application environments.

[0122] An embodiment of the present invention also provides a CAN communication system.

[0123] Figure 11 FIG. 1 is a CAN communication system architecture diagram of an embodiment, as shown in FIG. Figure 11 As shown, a CAN communication system according to one embodiment includes a CAN control system 1000 , a CAN bus network 1001 , and a CAN transceiver circuit 1002 according to any one of the above embodiments.

[0124] like Figure 11 As shown, the transmit data input terminal TXD and receive data output terminal RXD of the CAN transceiver circuit 1003 are respectively connected to the CAN control system 1000; the high-level CAN voltage input / output terminal CANH of the CAN transceiver circuit 1003 is connected to one line of the CAN bus network 1001, and the low-level CAN voltage input / output terminal CANL of the CAN transceiver circuit 1003 is connected to another line of the CAN bus network 1001. Based on this, a complete CAN communication system is formed.

[0125] In the aforementioned CAN communication system, when the controlled terminal B2 of the second controlled switch 101 is connected to the CAN control system and transmits a logic-high signal, both the first controlled switch 100 and the second controlled switch 101 are turned on. The first switch terminal K1 of the first controlled switch 100 outputs a logic-high signal as a high-level CAN voltage, while the first switch terminal K3 of the second controlled switch 101 outputs a logic-low signal as a low-level CAN voltage. Simultaneously, the output terminal of the received data output module 12 outputs a logic-low signal to the CAN control system 1000. Thus, the control data transmitting module 10, the control data receiving module 11, and the received data output module 12 implement complete transceiver functionality between the CAN bus network 1001 and the CAN control system 1000. Furthermore, because the control data transmitting module 10 utilizes discrete modules, namely the first controlled switch 100 and the second controlled switch 101, it can be easily replaced and the drive capability of the logic-high and logic-low signals output to the CAN bus network can be adjusted to meet the needs of different application environments.

[0126] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0127] The above embodiments merely illustrate several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A CAN transceiver circuit, characterized in that: It includes a control data sending module, a control data receiving module and a received data output module; The control data sending module includes a first controlled switch and a second controlled switch; the first switch end of the first controlled switch is used to connect to the CAN bus network and serve as a high-level CAN voltage input / output end; the controlled end of the first controlled switch is used to connect to a logic high level; the controlled end of the first controlled switch is connected to the first switch end of the second controlled switch; the first switch end of the second controlled switch is also used to connect to the CAN bus network and serve as a low-level CAN voltage input / output end; the second switch end of the second controlled switch is used to connect to the CAN control system and serve as a data sending input end; wherein, the first controlled switch is used to connect the first and second switch ends of the first controlled switch when the controlled end of the first controlled switch is connected to a logic low level; and the second controlled switch is used to connect the first and second switch ends of the second controlled switch when the controlled end of the second controlled switch is connected to a logic high level. The first receiving end of the control data receiving module is connected to the first switch end of the first controlled switch, and the second receiving end of the control data receiving module is connected to the first switch end of the second controlled switch; wherein the control data receiving module is configured to output a first logic level to the received data output module when the first receiving end is connected to a logic high level and the second receiving end is connected to a logic low level; and 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 connected to a logic low level; The input end of the received data output module is used to connect to the first logic level or the second logic level; the output end of the received data output module is used to connect to the CAN control system as a received data output end; the received data output module is used to output a logic low level to the CAN control system according to the first logic level, and the received data output module is used to output a logic high level to the CAN control system according to the second logic level; The control data sending module further includes a first isolation unit and a second isolation unit; The first switch end of the first controlled switch is used to connect to the CAN bus network through the first isolation unit; the first switch end of the second controlled switch is used to connect to the CAN bus network through the second isolation unit, and the first controlled switch and the second controlled switch both include semiconductor switches.

2. The CAN transceiver circuit according to claim 1, characterized in that: The first isolation unit includes a first diode, and the second isolation unit includes a second diode; The first switch end of the first controlled switch is connected to the anode of the first diode, and the cathode of the first diode is used to connect to the CAN bus network; The first switch end of the second controlled switch is connected to the cathode of the second diode, and the anode of the second diode is used to connect to the CAN bus network.

3. The CAN transceiver circuit according to claim 1, wherein: The control data sending module further includes a first voltage dividing module and a second voltage dividing module; The controlled end of the first controlled switch is used to access a logic high level through the first voltage divider module; the controlled end of the first controlled switch is also used to connect to the first switch end of the second controlled switch through the second voltage divider module.

4. The CAN transceiver circuit according to claim 1, wherein: The first controlled switch includes a first PNP transistor; the second controlled switch includes a first NPN transistor; The collector of the first PNP transistor is used to connect to the CAN bus network as a high-level CAN voltage input / output terminal; the emitter of the first PNP transistor is used to access a logic high level; the base of the first PNP transistor is connected to the collector of the first NPN transistor; the collector of the first NPN transistor is also used to connect to the CAN bus network as a low-level CAN voltage input / output terminal; the emitter of the first NPN transistor is used to access a logic low level; the base of the first NPN transistor is used to connect to the CAN control system as a data sending input terminal.

5. The CAN transceiver circuit according to claim 1, wherein: The control data receiving module includes a third controlled switch, a fourth controlled switch and a third voltage dividing module; The controlled end of the third controlled switch is connected to the first switch end of the first controlled switch, and the first switch end of the third controlled switch is used to connect to a logic high level; the second switch end of the third controlled switch is connected to the second switch end of the fourth controlled switch; wherein the third controlled switch is used to conduct the first switch end and the 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 to the first switch end of the second controlled switch, and the first switch end of the fourth controlled switch is used to connect to a logic low level through the third voltage divider module; wherein the fourth controlled switch is used to connect the first switch end and the second switch end of the fourth controlled switch when the controlled end of the fourth controlled switch is connected to a logic low level.

6. The CAN transceiver circuit according to claim 5, characterized in that: The third controlled switch and the fourth controlled switch each include a semiconductor switch.

7. The CAN transceiver circuit according to claim 6, characterized in that: The third controlled switch includes a second NPN transistor, and the fourth controlled switch includes a second PNP transistor; The base of the second NPN transistor is connected to the first switch terminal of the first controlled switch, and the collector of the second NPN transistor is used to access a logic high level; the emitter of the second NPN transistor is connected to the emitter of the second PNP transistor; The base of the second PNP transistor is connected to the first switch end of the second controlled switch, and the collector of the second PNP transistor is used to access a logic low level through the third voltage divider module.

8. The CAN transceiver circuit according to claim 7, characterized in that: The control data receiving module further includes 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 of the second NPN transistor is connected to the first switch end of the first controlled switch through the first bias resistor, and the base of the second NPN transistor is used to sequentially access a logic high level through the third bias resistor and the fifth bias resistor; The base of the second PNP transistor is connected to the first switch terminal of the second controlled switch through the second bias resistor; The base of the second PNP transistor is used to sequentially access a logic low level through the fourth bias resistor and the sixth bias resistor; A common end of the third bias resistor and the fifth bias resistor is connected to a common end of the fourth bias resistor and the sixth bias resistor.

9. The CAN transceiver circuit according to claim 7, characterized in that: The control data receiving module further includes a first filter capacitor and a second filter capacitor; The base of the second NPN transistor is used to access a logic low level through the first filter capacitor, and the base of the second PNP transistor is used to access a logic low level through the second filter capacitor.

10. The CAN transceiver circuit according to claim 1, characterized in that: The received data output module includes a fifth controlled switch and a pull-up module; The controlled end of the fifth controlled switch is used to access the first logic level or the second logic level, the first switch end of the fifth controlled switch is used to access a logic high level through the pull-up module, and the first switch end of the fifth controlled switch is used to connect to the CAN control system; the second switch end of the fifth controlled switch is used to access a logic low level; The fifth controlled switch is configured to turn on the first switch terminal and the second switch terminal of the fifth controlled switch when the controlled terminal of the fifth controlled switch is connected to the first logic level.

11. The CAN transceiver circuit according to claim 10, characterized in that: The fifth controlled switch includes a semiconductor switch.

12. The CAN transceiver circuit according to claim 11, characterized in that: The fifth controlled switch includes a third NPN transistor; The base of the third NPN transistor is used to access the first logic level or the second logic level, the collector of the third NPN transistor is used to access the logic high level through the pull-up module, and the collector of the third NPN transistor is used to connect to the CAN control system; the emitter of the third NPN transistor is used to access the logic low level.

13. A CAN communication system, characterized in that: The device comprises a CAN control system, a CAN bus network and a CAN transceiver circuit as claimed in any one of claims 1 to 12.

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