Control circuit for LIN signal slope

Abstract

The invention discloses an LIN signal slope control circuit. The control circuit comprises a slope control circuit, a drive control circuit, a level pull-up circuit and a level pull-down circuit. The slope control circuit is used for controlling the waveform change of a VNX voltage signal generated according to the second voltage signal and inputting a BIAS voltage signal converted and generated according to the VNX voltage signal into the driving control circuit; the driving control circuit is used for controlling the waveform change of a VND voltage signal generated according to the BIAS voltage signal and inputting the VND voltage signal into the level pull-up circuit; the level pull-up circuit is used for performing pull-up control on an output voltage signal of the control end according to the VND voltage signal; and the level pull-down circuit is used for performing pull-down control on the output voltage signal of the control end according to the first voltage signal, the second voltage signal and the third voltage signal. According to the invention, the signal change of the LIN can be detected to realize accurate negative feedback control, and the rising and falling edges of the LIN bus signal tend to be unchanged when the voltage and temperature of the LIN signal change.

Description

Technical Field

[0001] The present application relates to the field of integrated circuit design, and in particular to a control circuit for a LIN signal slope. Background Art

[0002] LIN (Local Interconnect Network) bus is a low-cost serial communication protocol based on UART / SCI (Universal Asynchronous Receiver / Serial Interface). LIN bus has low cost and good flexibility. It is widely used in body control areas such as doors, windows, lights and central locking in modern automotive electronic architecture.

[0003] At present, most LIN transceivers on the market are designed based on the open-loop principle or use a fixed slope. When the voltage and temperature change, it cannot be guaranteed that the slope signal of the LIN bus remains unchanged. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the defect in the prior art that an ideal LIN signal cannot be obtained by using a conventional slope control circuit, and to provide a control circuit for the slope of a LIN signal.

[0005] The present invention solves the above technical problems through the following technical solutions:

[0006] In a first aspect, a control circuit for a LIN signal slope is provided, the control circuit comprising: a first input terminal, a slope control circuit, a drive control circuit, a second input terminal, a third input terminal, a fourth input terminal, a level pull-up circuit, a level pull-down circuit, and an output terminal;

[0007] The second input terminal, the third input terminal, and the fourth input terminal are all electrically connected to one end of the level pull-down circuit, the first input terminal is electrically connected to one end of the slope control circuit, the other end of the slope control circuit is electrically connected to one end of the drive control circuit, the other end of the drive control circuit is electrically connected to one end of the level pull-up circuit, the other end of the level pull-up circuit is electrically connected to the output terminal, and the other end of the level pull-down circuit is electrically connected to the output terminal;

[0008] The second input terminal is used to input a first voltage signal, the third input terminal is used to input a second voltage signal, the fourth input terminal is used to input a third voltage signal, and the first input terminal is used to input the second voltage signal;

[0009] The slope control circuit is used to control the waveform change of the VNX voltage signal generated according to the second voltage signal, and input the BIAS voltage signal generated by converting the VNX voltage signal into the drive control circuit;

[0010] The drive control circuit is used to control the waveform change of the VND voltage signal generated according to the BIAS voltage signal, and input the VND voltage signal into the level pull-up circuit;

[0011] The level pull-up circuit is used to pull up the output voltage signal of the output end according to the VND voltage signal;

[0012] The level pull-down circuit is used to control the output voltage signal of the output end to be pulled down according to the first voltage signal, the second voltage signal and the third voltage signal.

[0013] Preferably, the driving control circuit comprises: a first control terminal, a current mirror circuit, a low level control circuit and a negative feedback structure circuit;

[0014] One end of the current mirror circuit is electrically connected to the low-level control circuit, the other end of the current mirror circuit is electrically connected to the negative feedback structure circuit, and the current mirror circuit, the low-level control circuit, and the negative feedback structure circuit are all electrically connected to the first control end;

[0015] The current mirror circuit, the low level control circuit, and the negative feedback structure circuit jointly control the slopes of the rising edge and the falling edge corresponding to the VND voltage signal input to the level pull-up circuit.

[0016] Preferably, the low-level control circuit comprises: a first PMOS tube, a first NMOS tube, a second NMOS tube, a third NMOS tube and a fourth NMOS tube;

[0017] The drain of the first PMOS tube is electrically connected to the drain of the first NMOS tube, the source of the first NMOS tube is electrically connected to the drain of the second NMOS tube, the source of the second NMOS tube is electrically connected to the drain of the third NMOS tube, and the source of the third NMOS tube is electrically connected to the gate of the fourth NMOS tube.

[0018] Preferably, the current mirror circuit includes a second PMOS tube and a third PMOS tube.

[0019] Preferably, the negative feedback structure circuit includes a fifth NMOS tube and a sixth NMOS tube; the gate of the fifth NMOS tube is electrically connected to the drain of the sixth NMOS tube.

[0020] Preferably, the slope control circuit comprises: a second control terminal, a control circuit, a detection circuit, a pull-up current circuit and a pull-down current circuit;

[0021] One end of the control circuit is electrically connected to one end of the detection circuit, the pull-up current circuit and the pull-down current circuit are both electrically connected to the other end of the detection circuit, and the control circuit, the detection circuit, the pull-up current circuit and the pull-down current circuit are all electrically connected to the second control end;

[0022] The control circuit, the detection circuit, the pull-up current circuit and the pull-down current circuit jointly control the slopes of the rising edge and the falling edge corresponding to the VNX voltage signal input to the second control terminal;

[0023] The second control terminal is used to amplify the VNX voltage signal and convert it into the BIAS voltage signal, and input the BIAS voltage signal into the drive control circuit.

[0024] Preferably, the control circuit comprises a high-level control circuit and a first amplifier;

[0025] The negative electrode of the first amplifier is electrically connected to the high-level control circuit, and the positive electrode of the first amplifier is electrically connected to the detection circuit;

[0026] The high level control circuit is used to control the rising edge corresponding to the VNX voltage signal.

[0027] Preferably, the detection circuit includes a fourth PMOS tube, a fifth PMOS tube, a sixth PMOS tube, a seventh NMOS tube, an eighth NMOS tube, a ninth NMOS tube, a tenth NMOS tube and an eleventh NMOS tube;

[0028] The fifth PMOS tube and the sixth PMOS tube are both electrically connected to the source of the fourth PMOS tube; the drain of the seventh NMOS tube and the gate of the eighth NMOS tube are both electrically connected to the drain of the fourth PMOS tube;

[0029] The drain of the ninth NMOS tube is electrically connected to the drain of the sixth PMOS tube, the source of the ninth NMOS tube is electrically connected to the drain of the tenth NMOS tube, and the gate of the tenth NMOS tube is electrically connected to the eleventh NMOS tube.

[0030] Preferably, the pull-up current circuit includes an eighth PMOS tube, a ninth PMOS tube and a twelfth NMOS tube;

[0031] The source of the ninth PMOS tube and the drain of the twelfth NMOS tube are both electrically connected to the drain of the eighth PMOS tube.

[0032] Preferably, the pull-down current circuit includes a tenth PMOS tube, a thirteenth NMOS tube and a fourteenth NMOS tube;

[0033] The drain of the thirteenth NMOS tube and the gate of the fourteenth NMOS tube are both electrically connected to the drain of the tenth PMOS tube.

[0034] The positive and progressive effect of the present invention is that a control circuit for the slope of a LIN signal is provided, and the signal change of the LIN is accurately detected through a slope control circuit, a drive control circuit, a level pull-up circuit and a level pull-down circuit, so as to realize accurate negative feedback control, and ensure that when the voltage temperature of the LIN signal changes, the rising and falling edges of the LIN bus signal tend to remain unchanged. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a first schematic diagram of the working principle of the LIN signal slope control circuit according to Embodiment 1 of the present invention.

[0036] Figure 2 This is a second schematic diagram of the working principle of the LIN signal slope control circuit according to Embodiment 1 of the present invention.

[0037] Figure 3 This is a circuit diagram of a first implementation of a LIN signal slope control circuit according to Embodiment 1 of the present invention.

[0038] Figure 4 This is a third schematic diagram of the working principle of the LIN signal slope control circuit according to Embodiment 1 of the present invention.

[0039] Figure 5 This is a circuit diagram of a second implementation of the LIN signal slope control circuit of Example 1 of the present invention.

[0040] Figure 6 This is a circuit diagram of a third implementation of the LIN signal slope control circuit of Example 1 of the present invention. DETAILED DESCRIPTION

[0041] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples.

[0042] Example 1

[0043] This embodiment provides a control circuit for the slope of a LIN signal. Figure 1 As shown, the control circuit includes a first input terminal 1, a slope control circuit 2, a drive control circuit 3, a second input terminal 4, a third input terminal 5, a fourth input terminal 6, a level pull-up circuit 7, a level pull-down circuit 8, and an output terminal 9;

[0044] The second input terminal 4, the third input terminal 5, and the fourth input terminal 6 are all electrically connected to one end of the level pull-down circuit 8, the first input terminal 1 is electrically connected to one end of the slope control circuit 2, the other end of the slope control circuit 2 is electrically connected to one end of the drive control circuit 3, the other end of the drive control circuit 3 is electrically connected to one end of the level pull-up circuit 7, the other end of the level pull-up circuit 7 is electrically connected to the output terminal 9, and the other end of the level pull-down circuit 8 is electrically connected to the output terminal 9;

[0045] The second input terminal 4 is used to input a first voltage signal, the third input terminal 5 is used to input a second voltage signal, the fourth input terminal 6 is used to input a third voltage signal, and the first input terminal 1 is used to input a second voltage signal;

[0046] The slope control circuit 2 is used to control the waveform change of the VNX voltage signal generated according to the second voltage signal, and input the BIAS voltage signal generated by converting the VNX voltage signal into the drive control circuit 3;

[0047] The driving control circuit 3 is used to control the waveform change of the VND voltage signal generated according to the BIAS voltage signal, and input the VND voltage signal into the level pull-up circuit;

[0048] The level pull-up circuit 7 is used to control the output voltage signal of the output terminal 9 to be pulled up according to the VND voltage signal;

[0049] The level pull-down circuit 8 is used to control the output voltage signal of the output terminal 9 to be pulled down according to the first voltage signal, the second voltage signal and the third voltage signal.

[0050] In this embodiment, after the second voltage signal is stably input to the slope control circuit 2 through the first input terminal 1, the slope control circuit 2 controls the rising edge and falling edge of the LIN driver gate voltage waveform by controlling the high level and the rising edge and falling edge of the VNX voltage signal. The drive control circuit 3 controls the VND waveform generated by the BIAS voltage signal, and the level pull-up circuit 7 controls the periodic change of the output voltage signal of the output terminal 9 by controlling the waveform change of the VND voltage signal, thereby controlling the slope of the LIN signal, and inputting the first voltage signal, the second voltage signal and the third voltage signal through the second input terminal 4, the third input terminal 5, and the fourth input terminal 6 to pull down the output voltage signal of the output terminal 9. This method ensures that the LIN signal is stably output under various conditions, accurately controls the LIN signal, and realizes accurate control of the rising edge and falling edge of the LIN signal.

[0051] Figure 2 The second schematic diagram of the working principle of the control circuit of the LIN signal slope, the drive control circuit 3 comprises: a current mirror circuit 31, a low level control circuit 32, a negative feedback structure circuit 33 and a first control terminal 34;

[0052] One end of the current mirror circuit 31 is electrically connected to the low level control circuit 32, the other end of the current mirror circuit 31 is electrically connected to the negative feedback structure circuit 33, and the current mirror circuit 31, the low level control circuit 32, and the negative feedback structure circuit 33 are all electrically connected to the first control terminal 34;

[0053] The current mirror circuit 31 , the low level control circuit 32 , and the negative feedback structure circuit 33 jointly control the slopes of the rising edge and the falling edge corresponding to the VND voltage signal input to the level pull-up circuit 7 .

[0054] In this embodiment, the branch where the current mirror circuit 31 is located, the branch where the low-level control circuit 32 is located, and the negative feedback structure circuit 33 jointly control the VND voltage signal, thereby controlling the waveform change of VND.

[0055] Figure 3 The circuit diagram of the first implementation of the control circuit of the LIN signal slope, the low level control circuit 32 includes: a first PMOS tube, a first NMOS tube, a second NMOS tube, a third NMOS tube and a fourth NMOS tube;

[0056] The drain of the first PMOS tube is electrically connected to the drain of the first NMOS tube, the source of the first NMOS tube is electrically connected to the drain of the second NMOS tube, the source of the second NMOS tube is electrically connected to the drain of the third NMOS tube, and the source of the third NMOS tube is electrically connected to the gate of the fourth NMOS tube.

[0057] The current mirror circuit 31 includes a second PMOS transistor and a third PMOS transistor.

[0058] The negative feedback structure circuit 33 includes a fifth NMOS tube and a sixth NMOS tube; the gate of the fifth NMOS tube is electrically connected to the drain of the sixth NMOS tube.

[0059] In this embodiment, the MP2 tube where the BIAS voltage is located controls the periodic change of the VND voltage signal, the low level control circuit 32 composed of MP1, MN1, MN2, MN3 and MN4 controls the low level signal of the first control terminal 34, and the negative feedback structure circuit 33 composed of MN5 and MN6 implements negative feedback control on the first control terminal 34. A level pull-down circuit 8 is formed by an MPOS tube and three MNOS tubes, and a level pull-up circuit 7 is formed by R3, R2, R4 and the MNOS tube electrically connected to R3, and the two jointly control the periodic change of the voltage signal at the GN-output terminal, thereby realizing accurate slope control of the LIN signal.

[0060] Figure 4The third schematic diagram of the working principle of the control circuit of the LIN signal slope, the slope control circuit 2 comprises: a second control terminal 21, a control circuit 22, a detection circuit 23, a pull-up current circuit 24 and a pull-down current circuit 25;

[0061] One end of the control circuit 22 is electrically connected to one end of the detection circuit 23, the pull-up current circuit 24 and the pull-down current circuit 25 are both electrically connected to the other end of the detection circuit 23, and the control circuit, the detection circuit, the pull-up current circuit 24 and the pull-down current circuit 25 are all electrically connected to the second control end 21;

[0062] The control circuit 22, the detection circuit 23, the pull-up current circuit 24 and the pull-down current circuit 25 jointly control the slopes of the rising edge and the falling edge corresponding to the VNX voltage signal input to the second control terminal 21;

[0063] The second control terminal 21 is used to amplify the VNX voltage signal and convert it into a BIAS voltage signal, and input the BIAS voltage signal into the drive control circuit 3 .

[0064] In this embodiment, the branch where the control circuit 22 is located, the branch where the detection circuit 23 is located, the branch where the pull-up current circuit 24 is located, and the branch where the pull-down current circuit 25 is located jointly control the VNX voltage signal, thereby controlling the waveform change of VNX, so that the waveform of VNX shows periodic changes.

[0065] Figure 5 A circuit diagram of a second implementation of a control circuit for a LIN signal slope, wherein the control circuit 22 includes a high-level control circuit and a first amplifier;

[0066] The negative electrode of the first amplifier is electrically connected to the high-level control circuit, and the positive electrode of the first amplifier is electrically connected to the detection circuit;

[0067] The high level control circuit is used to control the rising edge corresponding to the VNX voltage signal.

[0068] The detection circuit 23 includes a fourth PMOS transistor, a fifth PMOS transistor, a sixth PMOS transistor, a seventh NMOS transistor, an eighth NMOS transistor, a ninth NMOS transistor, a tenth NMOS transistor and an eleventh NMOS transistor;

[0069] The fifth PMOS tube and the sixth PMOS tube are both electrically connected to the source of the fourth PMOS tube; the drain of the seventh NMOS tube and the gate of the eighth NMOS tube are both electrically connected to the drain of the fourth PMOS tube;

[0070] The drain of the ninth NMOS tube is electrically connected to the drain of the sixth PMOS tube, the source of the ninth NMOS tube is electrically connected to the drain of the tenth NMOS tube, and the gate of the tenth NMOS tube is electrically connected to the eleventh NMOS tube.

[0071] The pull-up current circuit 24 includes an eighth PMOS transistor, a ninth PMOS transistor and a twelfth NMOS transistor;

[0072] The source of the ninth PMOS tube and the drain of the twelfth NMOS tube are both electrically connected to the drain of the eighth PMOS tube.

[0073] The pull-down current circuit 25 includes a tenth PMOS transistor, a thirteenth NMOS transistor and a fourteenth NMOS transistor;

[0074] The drain of the thirteenth NMOS tube and the gate of the fourteenth NMOS tube are both electrically connected to the drain of the tenth PMOS tube.

[0075] In this embodiment, MP4, MP5, MP6, MN7, MN8, MN9, MN10 and MN11 together constitute a detection circuit 23, MP8, MP9 and MN12 constitute a pull-up current circuit 24, MP10, MN13 and NM14 together constitute a pull-down current circuit 25, and amplifier follow and OPA1 together constitute a control circuit 23 to jointly control the waveform change of the VNX voltage signal, so that the waveform of VNX shows periodic changes, thereby controlling the amplification of the VNX voltage signal and converting it into the waveform change of the BIAS voltage signal.

[0076] Figure 6 This is a circuit diagram of a third implementation of the control circuit for the slope of the LIN signal. The control circuit 22 includes five MPOS tubes and two MNOS tubes, which control the high level of the VNX voltage signal to achieve precise control of the waveform of the VNX input to the second control terminal.

[0077] The present embodiment provides a control circuit for the slope of a LIN signal, which accurately detects changes in LIN signals through a slope control circuit, a drive control circuit, a level pull-up circuit, and a level pull-down circuit, so as to achieve accurate negative feedback control and ensure that when the voltage temperature of the LIN signal changes, the rising and falling edges of the LIN bus signal tend to remain unchanged.

[0078] Although the specific embodiments of the present invention are described above, it should be understood by those skilled in the art that this is only for illustration and the protection scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A LIN signal slope control circuit, characterized in that: The control circuit comprises a first input terminal, a slope control circuit, a drive control circuit, a second input terminal, a third input terminal, a fourth input terminal, a level pull-up circuit, a level pull-down circuit, and an output terminal; The second input terminal, the third input terminal, and the fourth input terminal are all electrically connected to one end of the level pull-down circuit, the first input terminal is electrically connected to one end of the slope control circuit, the other end of the slope control circuit is electrically connected to one end of the drive control circuit, the other end of the drive control circuit is electrically connected to one end of the level pull-up circuit, the other end of the level pull-up circuit is electrically connected to the output terminal, and the other end of the level pull-down circuit is electrically connected to the output terminal; The second input terminal is used to input a first voltage signal, the third input terminal is used to input a second voltage signal, the fourth input terminal is used to input a third voltage signal, and the first input terminal is used to input the second voltage signal; The slope control circuit is used to control the waveform change of the VNX voltage signal generated according to the second voltage signal, and input the BIAS voltage signal generated by converting the VNX voltage signal into the drive control circuit; The drive control circuit is used to control the waveform change of the VND voltage signal generated according to the BIAS voltage signal, and input the VND voltage signal into the level pull-up circuit; The level pull-up circuit is used to pull up the output voltage signal of the output end according to the VND voltage signal; The level pull-down circuit is used to control the output voltage signal of the output end to be pulled down according to the first voltage signal, the second voltage signal and the third voltage signal.

2. The LIN signal slope control circuit according to claim 1, characterized in that: The driving control circuit comprises: a first control terminal, a current mirror circuit, a low level control circuit and a negative feedback structure circuit; One end of the current mirror circuit is electrically connected to the low-level control circuit, the other end of the current mirror circuit is electrically connected to the negative feedback structure circuit, and the current mirror circuit, the low-level control circuit, and the negative feedback structure circuit are all electrically connected to the first control end; The current mirror circuit, the low level control circuit, and the negative feedback structure circuit jointly control the slopes of the rising edge and the falling edge corresponding to the VND voltage signal input to the level pull-up circuit.

3. The LIN signal slope control circuit according to claim 2, characterized in that: The low-level control circuit comprises: a first PMOS tube, a first NMOS tube, a second NMOS tube, a third NMOS tube and a fourth NMOS tube; The drain of the first PMOS tube is electrically connected to the drain of the first NMOS tube, the source of the first NMOS tube is electrically connected to the drain of the second NMOS tube, the source of the second NMOS tube is electrically connected to the drain of the third NMOS tube, and the source of the third NMOS tube is electrically connected to the gate of the fourth NMOS tube.

4. The LIN signal slope control circuit according to claim 2, characterized in that: The current mirror circuit includes a second PMOS tube and a third PMOS tube.

5. The LIN signal slope control circuit according to claim 2, characterized in that: The negative feedback structure circuit includes a fifth NMOS tube and a sixth NMOS tube; The gate of the fifth NMOS tube is electrically connected to the drain of the sixth NMOS tube.

6. The LIN signal slope control circuit according to claim 1, characterized in that: The slope control circuit comprises: a second control terminal, a control circuit, a detection circuit, a pull-up current circuit and a pull-down current circuit; One end of the control circuit is electrically connected to one end of the detection circuit, the pull-up current circuit and the pull-down current circuit are both electrically connected to the other end of the detection circuit, and the control circuit, the detection circuit, the pull-up current circuit and the pull-down current circuit are all electrically connected to the second control end; The control circuit, the detection circuit, the pull-up current circuit and the pull-down current circuit jointly control the slopes of the rising edge and the falling edge corresponding to the VNX voltage signal input to the second control terminal; The second control terminal is used to amplify the VNX voltage signal and convert it into the BIAS voltage signal, and input the BIAS voltage signal into the drive control circuit.

7. The LIN signal slope control circuit according to claim 6, characterized in that: The control circuit includes a high-level control circuit and a first amplifier; The negative electrode of the first amplifier is electrically connected to the high-level control circuit, and the positive electrode of the first amplifier is electrically connected to the detection circuit; The high level control circuit is used to control the rising edge corresponding to the VNX voltage signal.

8. The LIN signal slope control circuit according to claim 6, characterized in that: The detection circuit includes a fourth PMOS tube, a fifth PMOS tube, a sixth PMOS tube, a seventh NMOS tube, an eighth NMOS tube, a ninth NMOS tube, a tenth NMOS tube and an eleventh NMOS tube; The fifth PMOS tube and the sixth PMOS tube are both electrically connected to the source of the fourth PMOS tube; the drain of the seventh NMOS tube and the gate of the eighth NMOS tube are both electrically connected to the drain of the fourth PMOS tube; The drain of the ninth NMOS tube is electrically connected to the drain of the sixth PMOS tube, the source of the ninth NMOS tube is electrically connected to the drain of the tenth NMOS tube, and the gate of the tenth NMOS tube is electrically connected to the eleventh NMOS tube.

9. The LIN signal slope control circuit according to claim 6, characterized in that: The pull-up current circuit includes an eighth PMOS tube, a ninth PMOS tube and a twelfth NMOS tube; The source of the ninth PMOS tube and the drain of the twelfth NMOS tube are both electrically connected to the drain of the eighth PMOS tube.

10. The LIN signal slope control circuit according to claim 6, characterized in that: The pull-down current circuit includes a tenth PMOS tube, a thirteenth NMOS tube and a fourteenth NMOS tube; The drain of the thirteenth NMOS tube and the gate of the fourteenth NMOS tube are both electrically connected to the drain of the tenth PMOS tube.

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