LIN driving circuit, LIN bus and driving method

Abstract

The invention provides an LIN driving circuit, an LIN bus and a driving method. The LIN driving circuit comprises an input module, an output slope control module, n pull-down tubes and an output module, n is an integer greater than or equal to 2; the input module is connected between a first power supply voltage and a reference ground, receives a sending signal of an LIN node and outputs a control signal; the output slope control module is connected with a control signal, and n output ends are respectively connected with the grid electrodes of the corresponding pull-down tubes; when the sending signal is output at a low level, the pull-down tubes are conducted in sequence; when the sending signal output is a high level, the pull-down tubes are closed at the same time, and the impedance value in the output slope control module is reduced; source electrodes of the pull-down tubes are grounded, drain electrodes of the pull-down tubes are connected with a first end of the output module, and a second end of the output module is connected with a second power supply voltage. According to the invention, a traditional driving tube is divided into a plurality of driving tubes, each driving tube is provided with a capacitor, and the capacitors are charged to realize buffering, so that the slope of the output voltage is controlled.

Description

Technical Field

[0001] The present invention relates to the field of integrated circuits, and in particular to a LIN driving circuit, a LIN bus and a driving method. Background Art

[0002] LIN (Local Interconnect Network) bus is a low-cost serial communication protocol based on UART / SCI (Universal Asynchronous Receiver / Serial Interface), which can be used in various fields such as automobiles. It is mainly suitable for low-end communication between network module nodes inside the equipment, especially for serial communication of smart sensors and actuators. However, the current LIN bus drive circuit will have large voltage and current changes in a short period of time during operation, thus forming a large electromagnetic interference.

[0003] Based on this, the present invention proposes a LIN driving circuit, a LIN bus and a driving method, which are used to solve the electromagnetic interference problem caused by the rapid change of the driving voltage in the prior art.

[0004] It should be noted that the above introduction to the technical background is only for the convenience of providing a clear and complete description of the technical solutions of the present application and for the convenience of understanding by those skilled in the art. It cannot be considered that the above technical solutions are well known to those skilled in the art simply because they are described in the background technology section of the present application. Summary of the invention

[0005] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a LIN driving circuit, a LIN bus and a driving method, which are used to solve the problem of electromagnetic interference caused by rapid changes in driving voltage in the prior art.

[0006] To achieve the above-mentioned object and other related objects, the present invention provides a LIN driving circuit, comprising: an input module, an output slope control module, n pull-down tubes and an output module; n is an integer greater than or equal to 2;

[0007] The input module is connected between the first power supply voltage VDD and the reference ground, receives the transmission signal of the LIN node, and outputs the control signal;

[0008] The output slope control module is connected to the control signal, and the n output terminals are respectively connected to the gates of the corresponding pull-down tubes; when the sending signal output is a low level, the pull-down tubes are turned on in sequence; when the sending signal output is a high level, the pull-down tubes are turned off at the same time, and the impedance value in the output slope control module is reduced;

[0009] The source of each pull-down tube is grounded, the drain is connected to the first end of the output module, and the second end of the output module is connected to the second power supply voltage.

[0010] Optionally, the input module includes a pull-up circuit and a pull-down circuit; when the sending signal is at a low level, the pull-up circuit is enabled; the input end of the pull-up circuit is connected to the first power supply voltage VDD, and the output end is connected to the control end of the output slope control module; when the sending signal is at a high level, the pull-down circuit is enabled; the input end of the pull-down circuit is grounded, and the output end is connected to the control end of the output slope control module.

[0011] Optionally, the pull-up circuit includes a first current source and a first switch; the first end of the first current source is connected to the first supply voltage; the first end of the first switch is connected to the second end of the first current source, and the second end is connected to the output slope control module.

[0012] Optionally, the pull-down circuit includes a second current source and a second switch; the first end of the second current source is grounded; the first end of the second switch is connected to the output slope control module, and the second end is connected to the second end of the second current source.

[0013] Optionally, the output slope control module includes n RC filters and n switches; each switch is connected in parallel with the resistor in each RC filter, and the control end is connected to the switch control signal. When the switch control signal received is a high level, the resistor in each RC filter is short-circuited; wherein the switch control signal is in the same direction as the sending signal; the input end of the first RC filter is connected to the output end of the input module, and each RC filter is connected in series in sequence.

[0014] Optionally, the output module includes a second resistor; a first end of the second resistor is connected to the second supply voltage, and a second end of the second resistor is connected to a LIN output port.

[0015] Optionally, the LIN driving circuit further includes a low impedance protection module; the low impedance protection module is arranged between the input module and the output slope control module.

[0016] Optionally, the low impedance protection module is configured as an NMOS tube; the drain and gate of the NMOS tube are both connected to the output end of the input module, and the source is grounded.

[0017] Optionally, the LIN driving circuit further includes an output protection module; the output protection module is arranged between the output slope control module and the output module, and is used for overvoltage protection of the LIN output port.

[0018] Optionally, the output protection module includes a first diode and a second diode; the cathode of the first diode is connected to the output end of the output slope control module, and the anode is connected to the LIN output port; the cathode of the second diode is connected to the LIN output port, and the anode is connected to the first end of the output module.

[0019] The present invention also provides a LIN bus, comprising: a plurality of LIN nodes; each LIN node is provided with a load device and a LIN drive circuit as claimed in any one of claims 1 to 10; each node executes a response according to a signal output by the LIN drive circuit.

[0020] To achieve the above object and other related objects, the present invention further provides a driving method, which is implemented based on the above LIN driving circuit and includes:

[0021] Receive the transmission signal of LIN node and output the corresponding control signal;

[0022] When the sending signal is at a low level, the output slope control module turns on each pull-down tube in sequence;

[0023] When the sending signal is at a high level, the impedance value in the output slope control module turns off all the pull-down tubes at the same time and reduces the impedance value in the output slope control module.

[0024] Optionally, when the output slope control module includes n RC filters and n switches and the received switch control signal is at a high level, the resistors in each RC filter are short-circuited.

[0025] As described above, the LIN driving circuit, LIN bus and driving method of the present invention have the following beneficial effects:

[0026] 1. The LIN driving circuit, LIN bus and driving method of the present invention achieve the purpose of output voltage delay by dividing the traditional driving tube into multiple driving tubes and turning on each driving tube in turn, and finally control the slope of the LIN port output waveform, so that the LIN port output voltage increases step by step, avoiding the electromagnetic interference problem caused by large voltage changes.

[0027] 2. The LIN driving circuit, LIN bus and driving method of the present invention respectively set multiple RC filters before the corresponding driving tubes. When the driving tube output voltage is required, the capacitor charging and the resistor in the RC filter are used to allow the driving tube output voltage to be output step by step; when the driving tube output voltage is not required, the resistors in the RC filter are short-circuited to form multiple low-impedance loops, thereby improving the anti-interference ability of the LIN driving circuit and the LIN bus.

[0028] 3. The LIN driving circuit and LIN bus of the present invention have simple structures, and the driving method of the present invention is simple and convenient, which is convenient for large-scale promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Shown is a structural schematic diagram of the LIN driving circuit of the present invention.

[0030] Figure 2 Shown is a schematic structural diagram of the input module of the present invention.

[0031] Figure 3 Shown is a schematic diagram of the structure of a LIN node of the present invention.

[0032] Component number description

[0033] 1 LIN Node

[0034] 11 LIN driver circuit

[0035] 110a First inverter

[0036] 110b Second inverter

[0037] 111 Input Module

[0038] 111a Pull-up circuit

[0039] 111b pull-down circuit

[0040] 111c Bias current input unit

[0041] 112 Output slope control module

[0042] 1121 First RC filter

[0043] 1122 Second RC filter

[0044] 1123 Third RC filter

[0045] 113 Output protection module

[0046] 12 Load devices DETAILED DESCRIPTION

[0047] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0048] Please refer to 1~ Figure 3It should be noted that the illustrations provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner, and the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0049] like Figure 1 As shown, the present invention provides a LIN driving circuit 11, comprising: an input module 111, an output slope control module 112, n pull-down tubes and an output module; n is an integer greater than or equal to 2.

[0050] like Figure 1 As shown, the input module 111 is connected between the first power supply voltage VDD and the reference ground, receives the transmission signal TXD of the LIN node, and outputs a control signal.

[0051] Specifically, the input module 111 includes a pull-up circuit 111a and a pull-down circuit 111b. The input module 111 is connected to the transmission signal TXD, and when the transmission signal is at a low level, the pull-up circuit is enabled; when the transmission signal is at a high level, the pull-down circuit is enabled;

[0052] In one example, if Figure 1 As shown, the input module 111 is connected to the transmission signal TXD and generates a first switch control signal Specifically, the transmission signal TXD generates the first switch control signal Φ0 through the first inverter 110a and the second inverter 110b. The input terminal of the first inverter 110a is connected to the transmission signal TXD, and the output terminal outputs the first switch control signal The input end of the second inverter 110b is connected to the output end of the first inverter 110a, and the output end outputs the second switch control signal Φ0. The second switch control signal Φ0 is in the opposite direction to the transmission signal TXD, and the second switch control signal Φ0 is in the same direction as the transmission signal TXD. When the first switch control signal Φ0 is turned on and the second switch control signal Φ0 is turned off, the pull-up circuit 111a is turned on and a high-level control signal is provided to the output slope control module 112; when the first switch control signal When the second switch control signal Φ0 is turned on, the pull-down circuit 111 b provides a low-level control signal to the output slope control module 112 .

[0053] In another example, if Figure 2As shown, after receiving the transmission signal TXD, the input module 111 can directly control the conduction of either the pull-up circuit 111a or the pull-down circuit 111b based on the level state of the received transmission signal TXD. Figure 2 In the illustrated embodiment, the transmitting signal TXD is directly connected to the gates of the PMOS tube and the NMOS tube. The PMOS tube is configured as a switch of the pull-up circuit 111a. When the gate of the PMOS tube receives the transmitting signal TXD as a low level, the pull-up circuit 111a is selected; and the NMOS tube is configured as a switch of the pull-down circuit 111b. When the gate of the NMOS tube receives the transmitting signal TXD as a high level, the pull-down circuit 111b is selected.

[0054] It should be noted that the specific structure of the input module 111 is not limited to the present invention, and any setting that can control the conduction of any circuit of the pull-up circuit 111a or the pull-down circuit 111b based on the transmission signal TXD is within the protection scope of the present invention.

[0055] More specifically, the input end of the pull-up circuit 111 is connected to the first power supply voltage VDD, and the output end is connected to the control end of the output slope control module 112 .

[0056] As an example, the pull-up circuit 111a includes a first current source I1 and a first switch S1; the first end of the first current source I1 is connected to the first supply voltage VDD; the first end of the first switch S1 is connected to the second end of the first current source I1, and the second end is connected to the output slope control module 112.

[0057] In this embodiment, if Figure 2 As shown, the pull-up circuit 111a includes a first NMOS tube NM1, a first PMOS tube PM1, a second PMOS tube PM2 and a third PMOS tube PM3; the gate of the first NMOS tube NM1 is connected to the first bias voltage, the source is grounded, and the drain is connected to the drain of the first PMOS tube PM1; the source of the first PMOS tube PM1 is connected to the first power supply voltage VDD, and the gate is connected to the drain; the source of the second PMOS tube PM2 is connected to the first power supply voltage VDD, the gate is connected to the gate of the first PMOS tube PM1, and the drain is connected to the source of the third PMOS tube PM3; the gate of the third PMOS tube PM3 is connected to the sending signal TXD of the LIN node, and the drain is connected to the input end of the output slope control module 112.

[0058] More specifically, if Figure 2 As shown, the input end of the pull-down circuit 111 b is grounded, and the output end is connected to the control end of the output slope control module 112 .

[0059] As an example, the pull-down circuit 111b includes a second current source I2 and a second switch S2; the first end of the second current source I2 is grounded; the first end of the second switch S2 is connected to the output slope control module 112, and the second end is connected to the second end of the second current source I2.

[0060] In this embodiment, if Figure 2 As shown, the pull-down circuit 111b includes a second NMOS tube NM2 and a third NMOS tube NM3; the gate of the second NMOS tube NM2 is connected to the second bias voltage, the source is grounded, and the drain is connected to the source of the third NMOS tube NM3; the gate of the third NMOS tube NM3 is connected to the sending signal TXD of the LIN node, and the drain is connected to the input end of the output slope control module 112.

[0061] It should be noted that if Figure 2 As shown, the first bias voltage and the second bias voltage are equal, and are both set to the voltage output by the bias current input unit 111c. The bias current input unit 111c includes a bias current IB and a fourth NMOS tube NM4; the drain of the fourth NMOS tube NM4 is connected to the bias current IB, the source is grounded, and the gate is connected to the drain. The bias current IB and the fourth NMOS tube NM4 constitute the input side of the current mirror, respectively forming a current mirror with the first NMOS tube of the pull-up circuit 111a and the second NMOS tube of the pull-down circuit 111b. It should be noted that other power supply modes can also be set to provide the first bias voltage and the second bias voltage for the pull-up circuit 111a and the pull-down circuit 111b, respectively, and are not limited to this embodiment.

[0062] like Figure 1 As shown, the output slope control module 112 is connected to the control signal, and the n output terminals are respectively connected to the gates of the corresponding pull-down tubes. When the sending signal is received and the output is low level, each pull-down tube is turned on in turn; when the sending signal is received and the output is high level, each output terminal turns off each pull-down tube at the same time and reduces the impedance value in the output slope control module 112.

[0063] Specifically, the output slope control module 112 includes n RC filters and n switches; Figure 1As shown, each switch is connected in parallel with the resistor in each RC filter, and the control end is connected to the switch control signal. When the switch control signal is received at a high level, the resistor in each RC filter is short-circuited; wherein the switch control signal is in the same direction as the transmission signal. In this embodiment, when the transmission signal TXD is at a high level, the switch control signal is also at a high level. At this time, the output slope control module 112 turns off each pull-down tube at the same time, and at the same time, each resistor in the output slope control module 112 is short-circuited, thereby reducing the impedance value in the output slope control module 112.

[0064] More specifically, the input end of the first RC filter is connected to the output end of the input module 111, and the RC filters are connected in series in sequence, and the pull-down tubes are turned on in sequence through the series-connected RC filters.

[0065] In this embodiment, each RC filter includes a first resistor R1 and a capacitor C; the first end of each first resistor R1 is set as the input end of each RC filter; the upper plate of each capacitor C is connected to the second end of the corresponding first resistor R1 and serves as the output end of each RC filter, and the lower plate is grounded.

[0066] like Figure 1 As shown, the gate of each pull-down tube is connected to the corresponding output end of the output slope control module 112, the source is grounded, and the drain is connected to the first end of the output module, and the output signal of the output slope control module 112 provides the output module with a step-by-step pull-down current.

[0067] For ease of understanding, in this embodiment, n is set to 3, that is, there are 3 pull-down tubes. Each NMOS tube is sequentially recorded as the fifth NMOS tube NM5, the sixth NMOS tube NM6 and the seventh NMOS tube NM7. The corresponding output slope control module 112 has 3 output ports. In this embodiment, there are 3 RC filters, which are respectively recorded as the first RC filter 1121, the second RC filter 1122 and the third RC filter 1123. The first resistors in the three RC filters are respectively recorded as R1a, R1b, and R1c, and the capacitors C are respectively recorded as Ca, Cb, and Cc.

[0068] The following is a detailed analysis of the process in which the three pull-down tubes provide the output module with a step-by-step pull-down current: when the input module 111 receives a low-level transmission signal, the output voltage of the input module 111 first charges the capacitor Ca in the first RC filter 1121, then charges the capacitor Cb in the second RC filter 1122, and finally charges the capacitor Cc in the third RC filter 1123. In the process of charging each capacitor, the gate of each NMOS tube among the fifth NMOS tube NM5, the sixth NMOS tube NM6 and the seventh NMOS tube NM7 reaches the threshold voltage in turn and is turned on, that is, after the capacitor Ca in the first RC filter 1121 is charged, the gate of the corresponding fifth NMOS tube NM5 reaches the threshold voltage, and after the fifth NMOS tube NM5 is turned on, it charges the capacitor Cb in the next RC filter (i.e., the second RC filter 1122). This process is carried out in sequence, and finally the capacitors C in the RC filters of each level are charged in sequence, and the pull-down tubes corresponding to the RC filters of each level are turned on in sequence. Because the drain of each pull-down tube is connected to the output end of the output module, it is macroscopically represented as a multi-level drain current that increases step by step (relative to the output module, that is, the current that is pulled down step by step). In combination with the output module, the voltage slope of the final output to the LIN output port is controllable, avoiding the occurrence of large electromagnetic interference (EME) problems due to large changes in the output voltage.

[0069] The following is a detailed analysis of the process of simultaneously closing the three pull-down tubes and reducing the impedance value in the output slope control module 112: When the input module 111 receives the transmission signal TXD as a high level, the resistors in each RC filter are short-circuited, and each capacitor in the RC filter begins to discharge rapidly, and the voltage is output to the ground through the pull-down unit 111b of the input module 111. From a macroscopic point of view, the impedance value of each RC filter decreases, thereby forming multiple low-impedance paths, which reduces the electromagnetic interference of the LIN drive circuit 11.

[0070] It should be noted that the number of RC filters is not limited to this embodiment, and the number of RC filters can be set according to the actual needs of the output voltage. In addition, the structure of the output slope control module 112 is not limited to this embodiment, and any output slope control module 112 that can have a capacitor and control the step-by-step output of the driving voltage by cooperating with a pull-down tube is within the protection scope of this embodiment.

[0071] like Figure 1 As shown, the first end of the output module is connected to the drain of each pull-down tube, and the second end is connected to the second power supply voltage VBAT, and outputs a step-by-step decreasing driving voltage to the LIN output port based on the output signal of each pull-down tube.

[0072] Specifically, the output module includes a second resistor R2; the first end of the second resistor R2 is connected to the second power supply voltage VBAT, and the second end is connected to the LIN output port. In the LIN node, when the LIN drive circuit does not receive a response signal (in this embodiment, the input signal TXD is a high level), the voltage output by the output module to the LIN output port is a high level signal, which is recorded as an invisible level; when the LIN drive circuit receives a response signal (in this embodiment, the input signal TXD is a low level), the voltage output by the output module to the LIN output port is pulled down from a high level signal to a low level signal, which is recorded as a dominant level. Therefore, in this embodiment, when the LIN drive circuit receives a response signal, the output slope control module 112 outputs a step-by-step pull-down current, and the voltage output of the output module to the LIN output port will decrease step by step; when the LIN drive circuit does not receive a response signal, the output slope control module 112 does not provide a pull-down current, and the voltage output of the output module to the LIN output port will return to a high level state.

[0073] It should be noted that the structure of the output module is not limited to this embodiment, and any output module that can output a step-by-step decreasing driving voltage to the LIN output port based on the output signal of each pull-down tube is within the protection scope of this embodiment.

[0074] like Figure 1 As shown, the LIN driving circuit further includes a low impedance protection module; the low impedance protection module is arranged between the input module 111 and the output slope control module 112 to reduce the electromagnetic interference of the LIN driving circuit 11 .

[0075] Specifically, the low-impedance protection module is set as an NMOS tube, which is recorded as the eighth NMOS tube NM8 in this embodiment; the drain and gate of the eighth NMOS tube NM8 are connected to the output end of the input module 111, and the source is grounded. By setting the low-impedance protection module, it is ensured that the LIN drive circuit is not easily affected by signal interference when discharging.

[0076] like Figure 1 As shown, the LIN driving circuit further includes an output protection module 113; the output protection module 113 is arranged between the output slope control module 112 and the output module, and is used to perform overvoltage protection on the LIN output port.

[0077] Specifically, in this embodiment, the output protection module 115 includes a first diode D1 and a second diode D2; the cathode of the first diode D1 is connected to the output end of the output slope control module 112, and the anode is connected to the LIN output port; the cathode of the second diode D2 is connected to the LIN output port, and the anode is connected to the input end of the output module (i.e., the second end of the second resistor R2); it should be noted that other devices can also be set in the output protection module 115 to ensure the stability of the voltage output by the output port.

[0078] The present invention also provides a LIN bus, wherein the LIN bus comprises a plurality of nodes 1. Figure 3 As shown, each node 1 is provided with a load device 12 and the above-mentioned LIN driving circuit 11; each node 1 responds according to the signal output by the LIN driving circuit and supplies power to the load device 12. That is, when the voltage output by the driving circuit 11 decreases step by step, the subsequent load device 12 responds and enters the working state; when the voltage output by the driving circuit 11 maintains a high level, the subsequent load device 12 remains in the standby state.

[0079] Specifically, Figure 3 As shown, the load device 12 includes but is not limited to a capacitor CL, a resistor RL and a third diode D3. The lower plate of the capacitor CL is grounded, and the upper plate is connected to the output end (i.e., LIN output port) of the LIN drive circuit 11; the first end of the resistor RL is connected to the LIN output port, and the second end is connected to the cathode of the third diode; the anode of the third diode is connected to the second power supply voltage VBAT. It should be noted that the devices and connection relationships in the load device 12 can also be set to other structures, and are not limited to this embodiment.

[0080] The present invention also provides a driving method, which is implemented based on the above-mentioned LIN driving circuit 11, including: receiving a transmission signal of a LIN node and outputting a corresponding control signal; when the transmission signal is at a low level, the output slope control module 112 turns on each pull-down tube in sequence; when the transmission signal output is at a high level, the output slope control module 112 turns off each pull-down tube at the same time and reduces the impedance value in the output slope control module 112. The specific control process has been described above and will not be repeated here.

[0081] Specifically, in this embodiment, when the output slope control module 112 includes n RC filters and n switches and the received switch control signal is at a high level, the resistors in each RC filter are short-circuited to reduce the impedance value in the output slope control module 112 .

[0082] In summary, the present invention provides a LIN driving circuit, a LIN bus and a driving method, including: the present invention provides a LIN driving circuit, a LIN bus and a driving method, including: an input module, an output slope control module, n pull-down tubes and an output module; n is an integer greater than or equal to 2; the input module is connected between a first power supply voltage and a reference ground, receives a transmission signal of a LIN node, and outputs a control signal; the output slope control module is connected to the control signal, and the n output ends are respectively connected to the gates of corresponding pull-down tubes; when the transmission signal output is a low level, each pull-down tube is turned on in turn; when the transmission signal output is a high level, each pull-down tube is turned off at the same time, and the impedance value in the output slope control module is reduced; the source of each pull-down tube is grounded, the drain is connected to the first end of the output module, and the second end of the output module is connected to the second power supply voltage. The present invention divides the traditional driving tube into a plurality of driving tubes, and sets a capacitor for each driving tube respectively, and then realizes buffering through capacitor charging, thereby controlling the output voltage slope. Therefore, the present invention effectively overcomes the various shortcomings in the prior art and has a high industrial utilization value.

[0083] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A LIN driving circuit, characterized in that: The LIN driving circuit at least includes: an input module, an output slope control module, n pull-down tubes and an output module; n is an integer greater than or equal to 2; The input module is connected between the first power supply voltage VDD and the reference ground, receives the transmission signal of the LIN node, and outputs the control signal; The output slope control module is connected to the control signal, and the n output terminals are respectively connected to the gates of the corresponding pull-down tubes; when the sending signal output is a low level, the pull-down tubes are turned on in sequence; when the sending signal output is a high level, the pull-down tubes are turned off at the same time, and the impedance value in the output slope control module is reduced; The source of each pull-down tube is grounded, the drain is connected to the first end of the output module, and the second end of the output module is connected to the second power supply voltage.

2. The LIN driving circuit according to claim 1, characterized in that: The input module includes a pull-up circuit and a pull-down circuit; When the transmission signal is at a low level, the pull-up circuit is enabled; the input end of the pull-up circuit is connected to the first power supply voltage VDD, and the output end is connected to the control end of the output slope control module; When the sending signal is at a high level, the pull-down circuit is enabled; the input end of the pull-down circuit is grounded, and the output end is connected to the control end of the output slope control module.

3. The LIN driving circuit according to claim 2, characterized in that: The pull-up circuit includes a first current source and a first switch; A first end of the first current source is connected to the first supply voltage; The first end of the first switch is connected to the second end of the first current source, and the second end of the first switch is connected to the output slope control module.

4. The LIN driving circuit according to claim 2, characterized in that: The pull-down circuit includes a second current source and a second switch; A first terminal of the second current source is grounded; A first end of the second switch is connected to the output slope control module, and a second end of the second switch is connected to the second end of the second current source.

5. The LIN driving circuit according to claim 1, characterized in that: The output slope control module includes n RC filters and n switches; Each switch is connected in parallel with a resistor in each RC filter, and the control end is connected to a switch control signal. When the switch control signal is received at a high level, the resistor in each RC filter is short-circuited; wherein the switch control signal is in the same direction as the transmission signal; The input end of the first RC filter is connected to the output end of the input module, and the RC filters are connected in series in sequence.

6. The LIN driving circuit according to claim 1, characterized in that: The output module includes a second resistor; a first end of the second resistor is connected to the second supply voltage, and a second end of the second resistor is connected to the LIN output port.

7. The LIN driving circuit according to claim 1, characterized in that: The LIN driving circuit further includes a low impedance protection module; the low impedance protection module is arranged between the input module and the output slope control module.

8. The LIN driving circuit according to claim 7, characterized in that: The low impedance protection module is configured as an NMOS tube; the drain and gate of the NMOS tube are both connected to the output end of the input module, and the source is grounded.

9. The LIN driving circuit according to any one of claims 1 to 8, characterized in that: The LIN driving circuit also includes an output protection module; the output protection module is arranged between the output slope control module and the output module, and is used for overvoltage protection of the LIN output port.

10. The LIN driving circuit according to claim 9, characterized in that: The output protection module includes a first diode and a second diode; The cathode of the first diode is connected to the output end of the output slope control module, and the anode is connected to the LIN output port; The cathode of the second diode is connected to the LIN output port, and the anode of the second diode is connected to the first end of the output module.

11. A LIN bus, characterized in that: The LINE bus at least comprises: a plurality of LIN nodes; each LIN node is provided with a load device and a LIN driving circuit as claimed in any one of claims 1 to 10; each node executes a response according to a signal output by the LIN driving circuit.

12. A driving method, implemented based on the LIN driving circuit according to any one of claims 1 to 10, characterized in that: The driving method at least comprises: Receive the transmission signal of LIN node and output the corresponding control signal; When the sending signal is at a low level, the output slope control module turns on each pull-down tube in sequence; When the sending signal is at a high level, the output slope control module turns off each pull-down tube at the same time and reduces the impedance value in the output slope control module.

13. The driving method according to claim 12, characterized in that: When the output slope control module includes n RC filters and n switches and the received switch control signal is at a high level, the resistors in each RC filter are short-circuited.

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