Pulse activation circuit

Abstract

The present application discloses a pulse activation circuit. The circuit includes: a signal isolation module, which is used to receive a CAN differential signal and generate a level signal electrically isolated from the CAN differential signal; a pulse generation module, which is connected to the signal isolation module, and is used to receive a CAN differential signal, and short-circuit the CAN differential signal after the level signal is generated, so that the level signal becomes a pulse signal; a power-on control module, which is used to connect a power supply and control the power supply to power on the main control module according to a pulse signal; a power-on self-holding module, which is used to connect the main control module and is connected to the power-on control module to receive a self-holding signal output after the main control module is powered on, so that the power-on control module controls the power supply to power on the main control module according to the self-holding signal. The pulse activation circuit provided by the present application activates the power-on system in a pulse manner, reducing the circuit cost. In addition, the present application electrically isolates the CAN signal from the pulse signal, and the power-on system is not affected by the CAN signal, thereby improving the reliability of the operation of the power-on system.

Description

Technical Field

[0001] The present application relates to the field of circuit technology, and in particular to a pulse activation circuit. Background Art

[0002] In modern automotive electronic systems, in order to achieve efficient communication between different components of the vehicle, the controller area network (CAN) is usually used as the main means of data exchange. Among them, a common technical solution is to use a CAN transceiver with a CAN wake-up function to manage the power status of the vehicle system. Specifically, when the car is in sleep mode, when a specific CAN differential signal is detected, the CAN transceiver can be awakened from the sleep state and further activate other parts of the vehicle. For example, when the CAN transceiver receives a specific CAN differential signal, the CAN transceiver can send an interrupt signal to the enable port of the DC-DC converter, thereby starting the power supply and powering on other systems or devices that require power.

[0003] However, the existing transceiver technology based on CAN wake-up function has some shortcomings. First, since the CAN wake-up circuit is directly connected to the CAN communication bus without physical isolation measures, it may be affected by other activities on the CAN bus, thereby reducing the stability and security of the system. Second, transceivers with CAN wake-up function are usually expensive in the market, which increases product costs. Summary of the invention

[0004] In view of the above problems, the present application provides a pulse activation circuit to solve the above technical problems.

[0005] The present application provides a pulse activation circuit, comprising:

[0006] A signal isolation module, used for receiving a CAN differential signal and generating a level signal electrically isolated from the CAN differential signal;

[0007] A pulse generating module, connected to the signal isolating module, for receiving a CAN differential signal and short-circuiting the CAN differential signal after the level signal is generated, so that the level signal becomes a pulse signal;

[0008] A power-on control module, used to connect to a power source and control the power source to power on the main control module according to the pulse signal;

[0009] The power-on self-holding module is used to connect to the main control module and the power-on control module to receive the self-holding signal output by the main control module after power-on, so that the power-on control module controls the power supply to power on the main control module according to the self-holding signal.

[0010] The pulse activation circuit provided by the present application receives the CAN differential signal through the signal isolation module and generates a level signal electrically isolated from the CAN differential signal, and then short-circuits the CAN differential signal through the pulse generation module, so that the level signal generated by the signal isolation module becomes a pulse signal, and the power-on control module controls the power supply to power on the main control module according to the pulse signal, and the main control module outputs a self-holding signal after powering on, and the power-on self-holding module enables the power-on control module to continue to control the power supply to power on the main control module after the pulse signal disappears according to the self-holding signal to realize the power-on self-holding of the main control module. The pulse activation circuit provided by the present application realizes the activation of the power-on system (i.e., the main control module) in a pulse manner, and only needs to receive a frame of CAN signal to trigger the pulse to activate the system, and isolates the CAN signal from the system, so that when the CAN signal is subjected to external abnormal high voltage, the power-on system will not be affected in any way, thereby improving the reliability of the operation of the power-on system. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0012] Figure 1 A module schematic diagram of a pulse activation circuit provided in an embodiment of the present application is shown.

[0013] Figure 2 A schematic diagram of the structure of a pulse activation circuit provided in an embodiment of the present application is shown.

[0014] Figure 3 Another structural schematic diagram of the pulse activation circuit provided in an embodiment of the present application is shown.

[0015] Figure 4 Another structural schematic diagram of the pulse activation circuit provided in an embodiment of the present application is shown.

[0016] Figure 5 Another structural schematic diagram of the pulse activation circuit provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0017] In order to enable those skilled in the art to better understand the solutions of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present application.

[0018] In the embodiments of the present application, it should be noted that, in this article, relational terms such as first and second, etc. are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations.

[0019] Moreover, the terms "comprises," "comprising," or any other variation thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0020] In addition, the "plurality" in the embodiments of the present application refers to two or more than two. In view of this, in the embodiments of the present application, "plurality" can also be understood as "at least two". "At least one" can be understood as one or more, for example, one, two or more. For example, including at least one means including one, two or more, and there is no limit on which ones are included. For example, including at least one of A, B and C, then A, B, C, A and B, A and C, B and C, or A, B and C can be included.

[0021] It should be noted that in the embodiments of the present application, "connection" can be understood as electrical connection, and the connection between two electrical components can be a direct or indirect connection between the two electrical components. For example, the connection between A and B can be either a direct connection between A and B or an indirect connection between A and B through one or more other electrical components.

[0022] The first end of each transistor used in the embodiment of the present application is one of the source and the drain, and the second end of each transistor is the other of the source and the drain. Since the source and the drain of the transistor can be symmetrical in structure, the source and the drain can be indistinguishable in structure, that is, the first end and the second end of the transistor in the embodiment of the present application can be indistinguishable in structure.

[0023] The embodiment of the present application provides a pulse activation circuit, Figure 1 The module schematic diagram of the pulse activation circuit provided in the embodiment of the present application is shown as follows: Figure 1 As shown, the pulse activation circuit provided in the embodiment of the present application includes a signal isolation module, a pulse generation module, a power-on control module and a power-on self-holding module.

[0024] Among them, the signal isolation module is used to receive the CAN differential signal (CANH and CANL) and generate a level signal electrically isolated from the CAN differential signal. The pulse generation module is connected to the signal isolation module and is used to receive the CAN differential signal (CANH and CANL). After the level signal is generated, the CAN differential signal is short-circuited to make the level signal a pulse signal. The power-on control module is used to connect the power supply and control the power supply to power on the main control module according to the pulse signal. The power-on self-holding module is used to connect the main control module and is connected to the power-on control module to receive the self-holding signal output by the main control module after powering on, so that the power-on control module controls the power supply to power on the main control module according to the self-holding signal.

[0025] In some embodiments, the pulse activation circuit provided in the embodiments of the present application is applied to automotive electronic systems, and in automotive electronic systems, batteries are usually used to power various systems. That is, in the above embodiments, the power supply refers to a battery module. At this time, in the embodiments of the present application, connecting the power supply means connecting the positive pole of the power supply, and grounding means connecting the negative pole of the power supply.

[0026] The pulse activation circuit provided in the embodiment of the present application receives the CAN differential signal through the signal isolation module and generates a level signal electrically isolated from the CAN differential signal, and then short-circuits the CAN differential signal through the pulse generation module, so that the level signal generated by the signal isolation module becomes a pulse signal, and the power-on control module controls the power supply to power on the main control module according to the pulse signal, and the main control module outputs a self-holding signal after power-on, and the power-on self-holding module enables the power-on control module to continue to control the power supply to power on the main control module after the pulse signal disappears according to the self-holding signal to realize the power-on self-holding of the main control module. The pulse activation circuit provided in the embodiment of the present application realizes the activation of the power-on system in a pulse manner, and only needs to receive a frame of CAN signal to trigger the pulse to activate the system. The entire activation process does not require the participation of the CAN transceiver, thereby avoiding the circuit cost brought by the CAN transceiver.

[0027] It can be understood that the pulse activation circuit provided in the embodiment of the present application converts the CAN differential signal into a pulse signal to activate the power-on system with a pulse signal, wherein the embodiment of the present application refers to the power-on system here by the main control module. That is to say, in different application scenarios, the specific structure of the main control module may be different. For example, the main control module can be a control system such as MCU, single-chip microcomputer, FPGA, etc.

[0028] In some embodiments, Figure 2 The structure diagram of the pulse activation circuit provided in the embodiment of the present application is shown as follows: Figure 2 As shown, in the embodiment of the present application, the signal isolation module includes a first resistor R1, a first diode D1 and an optical coupler U1.

[0029] The first end of the first resistor R1 is used to connect the high signal line in the CAN bus, and the second end is respectively connected to the cathode of the first diode D1, the anode input end of the optical coupler U1 and the pulse generating module; the anode of the first diode D1 is used to connect the low signal line in the CAN bus, and is connected to the cathode input end of the optical coupler U1; the output end of the optical coupler U1 is connected to the power-on control module. Optionally, the CAN bus outputs a CAN differential signal, so that the anode input end and the cathode input end of the light-emitting diode in the optical coupler U1 are turned on, thereby generating a level signal to turn on the optical coupler, and the optical coupler U1 will make the CAN differential signal and the level signal electrically isolated, that is, the CAN differential signal and the power-on control module, the power-on self-holding module, the power supply, and the main control module are all electrically isolated, so that when the CAN signal is subjected to external abnormal high voltage, the power-on system will not be affected in any way, thereby improving the reliability of the operation of the power-on system.

[0030] The first resistor R1 is used as a current limiting resistor of the CAN differential signal to prevent the CAN differential signal from being short-circuited, and the first diode D1 is used as a protection diode of the optical coupler U1 to prevent the optical coupler U1 from being broken down when the CAN differential signal has a negative voltage.

[0031] It is understandable that if Figure 2 As shown, the high signal line in the CAN bus is used to output the high level signal (ie, CANH) in the CAN differential signal, and the low signal line in the CAN bus is used to output the low level signal (ie, CANL) in the CAN differential signal.

[0032] In some embodiments, Figure 2 As shown, in the implementation of the present application, the pulse generating module includes a first switch unit Q1, a first delay unit C1, a second resistor R2, a third resistor R3 and a second diode D2.

[0033] The control end of the first switch unit Q1 is respectively connected to the first end of the first delay unit C1, the first end of the second resistor R2, and the first end of the third resistor R3; the first end of the first switch unit Q1 is respectively connected to the second end of the first delay unit C1, the second end of the third resistor R3, and the low signal line in the CAN bus; the second end of the first switch unit Q1 is connected to the signal isolation module for receiving the high level signal (CANH) in the CAN differential signal; the anode of the second diode D2 is used to connect the high signal line (CANH) in the CAN bus, and the cathode of the second diode D2 is connected to the second end of the second resistor R2; the first delay unit C1 is used to control the delayed conduction of the first switch unit Q1 to short-circuit the CAN differential signal after the signal isolation module generates a level signal. Optionally, after the CAN bus outputs a CAN differential signal, the signal isolation module first receives the CAN differential signal, thereby generating a level signal to drive the optocoupler U1 to turn on. At the same time, the CAN differential signal also charges the first delay unit C1. During the charging process, both ends of the first delay unit C1 are equivalent to a short circuit. At this time, the first switch unit Q1 is disconnected. When the first delay unit C1 is fully charged, both ends of the first delay unit C1 are equivalent to an open circuit. At this time, the first switch unit Q1 is turned on, so that the high level signal (CANH) in the CAN differential signal is short-circuited to the low level signal (CANL) in the CAN differential signal through the first switch unit Q1, and then the optocoupler U1 will no longer receive the CAN differential signal. Therefore, the level signal generated by the optocoupler U1 is a pulse signal.

[0034] Specifically, the second resistor R2 and the third resistor R3 are used to provide a bias voltage for the control terminal of the first switch unit Q1, and the second diode D2 is used as an anti-reverse diode.

[0035] In some embodiments, in the pulse activation circuit provided by the embodiments of the present application, the first delay unit C1 includes a first capacitor C1.

[0036] It is understandable that in the embodiment of the present application, the selection of the first delay unit is not limited to capacitor devices. In fact, if the circuit cost is not considered, the first delay unit can be set to a complex delay circuit or delay chip.

[0037] In some embodiments, in the pulse activation circuit provided by the embodiments of the present application, the first switch unit Q1 includes an N-type MOS tube Q1.

[0038] It is understandable that, in the embodiment of the present application, the first resistor R1 in the signal isolation module is also used to avoid abnormalities after the CAN differential signal is short-circuited. For example, the terminal resistance of the physical layer of the CAN bus is usually recommended to be 60 ohms. When the first switch unit Q1 is closed, the terminal resistance will be connected in parallel with the first resistor R1. The embodiment of the present application can control the parallel impedance of the two by setting the resistance value of the first resistor R1, so that the current output by the CAN bus after parallel connection flows through the parallel impedance to generate a CAN differential signal that meets the differential level range of the physical layer of the CAN bus.

[0039] The pulse activation circuit provided in the embodiment of the present application realizes the activation of the power-on system (i.e., the main control module) in a pulse manner. It only needs to receive one frame of CAN signal to trigger the pulse to activate the system, and isolate the CAN signal from the power-on system. In this way, when the CAN signal is subjected to external abnormal high voltage, the power-on system will not be affected in any way, thereby improving the reliability of the operation of the power-on system.

[0040] In some embodiments, Figure 2 As shown, in the embodiment of the present application, the power-on control module includes a second switch branch, a third switch branch, a fourth switch branch, a second delay unit and a voltage conversion unit.

[0041] Among them, the second switch branch is used to connect the power supply, and is respectively connected to the signal isolation module, the third switch branch and the second delay unit; optionally, the second switch branch is turned on after receiving a pulse signal (that is, the optical coupler U1 is closed), and when the pulse signal disappears (that is, the optical coupler U1 is disconnected), the second switch branch is disconnected.

[0042] The third switch branch is also connected to the second delay unit, the fourth switch branch and the power-on self-holding module; optionally, the third switch branch is arranged after the second switch branch and can only be turned on after the second switch branch is turned on.

[0043] The first end of the second delay unit is respectively connected to the second switch branch and the third switch branch, and the second end of the second delay unit is used for grounding, so as to delay the disconnection of the third switch branch after the second switch branch is disconnected; optionally, when the pulse signal disappears, the second delay unit is used to delay the disconnection of the third switch branch, so as to reserve a certain time margin for the power-on self-holding signal to receive the self-holding signal output by the main control module.

[0044] The fourth switch branch is used to connect the power supply, and is also respectively connected to the voltage conversion unit and the power-on self-holding module, so as to control the power supply to supply power to the voltage conversion unit after being turned on; optionally, the fourth switch branch is arranged after the third switch branch, and when the third switch branch is turned on, the fourth switch branch follows the third switch branch to be turned on, and when the third switch branch is disconnected, the fourth switch branch will continue to be turned on following the power-on self-holding module, so that the power supply supplies power to the voltage conversion unit through the fourth switch branch.

[0045] The voltage conversion unit is used to step down the voltage output by the power supply to provide a power-on voltage for the main control module. Optionally, the power supply voltage is usually much higher than the voltage required by the power-on system (i.e., the main control module). Therefore, the embodiment of the present application sets a voltage conversion unit to step down the power supply voltage and then power on the main control module.

[0046] It can be understood that in the embodiments of the present application, there is no limitation on the specific structures of the second switch branch, the third switch branch, the fourth switch branch, the second delay unit and the voltage conversion unit, as long as the technical features described in the above embodiments can be implemented. For example, the voltage conversion unit can use a step-down chip, and a well-known step-down circuit can also be manually built by the designer.

[0047] In some embodiments, Figure 3 Another structural schematic diagram of the pulse activation circuit provided in the embodiment of the present application is shown in FIG. Figure 3 As shown, in the embodiment of the present application, the second switch branch includes a second capacitor C2, a third capacitor C3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a third diode D3 and a second switch unit Q2.

[0048] Among them, the first end of the second capacitor C2 is respectively connected to the first end of the fourth resistor R4 and the first end of the fifth resistor R5, the second end of the second capacitor C2 is used for grounding, the second end of the fourth resistor R4 is used for grounding, the second end of the fifth resistor R5 is connected to the signal isolation module (the output end of the optical coupler U1), the first end of the third capacitor C3 is respectively connected to the first end of the sixth resistor R6, the first end of the seventh resistor R7, the cathode of the third diode D3 and the first end of the second switch unit Q2, the second end of the third capacitor C3 is used to connect to the power supply and is connected to the second end of the sixth resistor R6, the second end of the seventh resistor R7 is respectively connected to the anode of the third diode D3, the control end of the second switch unit Q2 and the signal isolation module (the output end of the optical coupler U1), the first end of the eighth resistor R8 is connected to the second end of the second switch unit Q2, and the second end of the eighth resistor R8 is respectively connected to the second delay unit C4 and the third switch branch.

[0049] Optionally, in the second switch branch, after receiving the pulse signal (the optical coupler U1 is closed), the second capacitor C2 is charged through the loop of the third capacitor C3, the seventh resistor R7, the optical coupler U1, and the fifth resistor R5. At the charging moment, the second capacitor C2 is equivalent to a short circuit. After the second capacitor C2 short-circuits the fourth resistor R4, the voltage across the seventh resistor R7 will rise to the opening threshold of the second switch unit Q2. At this time, the second switch unit Q2 is closed, that is, the second switch branch is closed. When the second capacitor C2 is full, the two ends are equivalent to an open circuit, and the voltage across the seventh resistor R7 will drop below the opening threshold of the second switch unit Q2. At this time, the second switch unit Q2 is disconnected, that is, the second switch branch is disconnected. Therefore, the embodiment of the present application can adjust the opening time of the second switch unit Q2 by adjusting the capacitance of the second capacitor. In addition, the disappearance of the pulse signal will also cause the second switch branch to be disconnected.

[0050] In the embodiment of the present application, the third diode D3 is used as a protection diode of the second switch unit Q2 to protect the second switch unit from being broken down, the seventh resistor R7 and the fifth resistor R5 are used to provide a bias voltage for the second switch unit Q2, the fourth resistor R4 and the sixth resistor R6 are used to provide a discharge circuit for the second capacitor C2 and the third capacitor C3, respectively, and the eighth resistor R8 is a current limiting resistor. That is to say, in the embodiment of the present application, the third diode D3, the seventh resistor R7 and the fifth resistor R5, the fourth resistor R4, the sixth resistor R6, and the eighth resistor R8 can also be replaced by circuits with corresponding functions.

[0051] In some embodiments, in the pulse activation circuit provided by the embodiments of the present application, the second switch unit Q2 includes a P-type MOS tube Q2.

[0052] In some embodiments, Figure 3 As shown, in the embodiment of the present application, the third switch branch includes a third switch unit Q3, a ninth resistor R9 and a tenth resistor R10.

[0053] The control end of the third switch unit Q3 is respectively connected to the first end of the ninth resistor R9 and the first end of the tenth resistor R10, the first end of the third switch unit Q3 is respectively connected to the fourth switch branch and the power-on self-holding module, the second end of the third switch unit Q3 is used for grounding, the second end of the ninth resistor R9 is respectively connected to the second delay unit C4 and the second switch branch, and the second end of the tenth resistor R10 is used for grounding.

[0054] Optionally, after the second switch branch is closed, the current charges the second delay unit C4 through the third capacitor C3, the second switch unit Q2, and the eighth resistor R8 in sequence, and at the same time provides a bias voltage for turning on the third switch unit Q3 to the ninth resistor R9 and the tenth resistor R10. When the second switch branch is disconnected, the third switch unit Q3 maintains a closed state through the second delay unit C4, thereby delaying the disconnection time of the third switch unit Q3, so as to reserve a certain time for the power-on self-holding module to receive the self-holding signal output by the main control module. The embodiment of the present application can adjust the closing time of the third switch unit Q3 by adjusting the capacitance of the third capacitor C3 and the fourth capacitor C4.

[0055] In some embodiments, the second delay unit C4 includes a fourth capacitor C4.

[0056] In the embodiment of the present application, the ninth resistor R9 and the tenth resistor R10 are used to provide a bias voltage for the third switch unit Q3, and the fourth capacitor C4 is used to extend the closing time of the third switch unit Q3. That is, in the embodiment of the present application, the ninth resistor R9, the tenth resistor R10 and the fourth capacitor C4 can also be replaced by circuits with corresponding functions.

[0057] In some embodiments, in the pulse activation circuit provided by the embodiments of the present application, the third switch unit Q3 includes an N-type MOS tube Q3.

[0058] In some embodiments, Figure 3 As shown, in the embodiment of the present application, the fourth switch branch includes a fourth switch unit Q4, an eleventh resistor R11, a twelfth resistor R12 and a fourth diode D4;

[0059] The control end of the fourth switch unit Q4 is respectively connected to the first end of the eleventh resistor R11, the first end of the twelfth resistor R12 and the anode of the fourth diode D4, the first end of the fourth switch unit Q4 is connected to the voltage conversion unit, the second end of the fourth switch unit Q4 is used to connect to the power supply, and is respectively connected to the second end of the eleventh resistor R11 and the cathode of the fourth diode D4, and the second end of the twelfth resistor R12 is respectively connected to the third switch branch and the power-on self-holding module.

[0060] Optionally, after the third switch branch is closed, the bias voltage formed by the eleventh resistor R11 and the twelfth resistor R12 closes the fourth switch unit Q4, the power supply provides the power supply voltage to the voltage conversion unit through the fourth switch unit Q4, and the voltage conversion unit steps down the power supply voltage and outputs it to the main control module.

[0061] In the embodiment of the present application, the eleventh resistor R11 and the twelfth resistor R12 are used to provide a bias voltage for the fourth switch unit Q4, and the fourth diode D4 is used to protect the fourth switch unit Q4 from being broken down by the power supply voltage. That is to say, in the embodiment of the present application, the eleventh resistor R11, the twelfth resistor R12 and the fourth diode D4 can also be replaced by circuits with corresponding functions.

[0062] In some embodiments, in the pulse activation circuit provided by the embodiments of the present application, the fourth switch unit Q4 includes a P-type MOS tube Q4.

[0063] In some embodiments, Figure 4 Another structural schematic diagram of the pulse activation circuit provided in the embodiment of the present application is shown. Figure 4 As shown, the fourth switch branch is further used to use the power supply voltage as an enable signal of the voltage conversion unit after being turned on, so as to control the voltage conversion unit to work after receiving the enable signal.

[0064] In some embodiments, Figure 3 As shown, in the embodiment of the present application, the power-on self-holding module includes a fifth switch unit Q5, a thirteenth resistor R13 and a fourteenth resistor R14.

[0065] The control end of the fifth switch unit Q5 is respectively connected to the first end of the thirteenth resistor R13 and the first end of the fourteenth resistor R14, the first end of the fifth switch unit Q5 is connected to the power-on control module, the second end of the fifth switch unit Q5 is used for grounding and is connected to the second end of the fourteenth resistor R14, and the second end of the thirteenth resistor R13 is used to connect to the main control module.

[0066] Optionally, after the main control module is powered on, it controls the preset IO interface to output a high-level signal as a power-on self-holding signal, and the power-on self-holding signal controls the fifth switch unit Q5 to be turned on, and then controls the fourth switch branch to continue to be turned on through the power-on self-holding module to achieve the power-on self-holding state of the main control module. When the main control module needs to be powered off, it can also output a low-level signal to control the fifth switch unit Q5 to be disconnected, thereby disconnecting the fourth switch branch to achieve the power-off operation.

[0067] In the embodiment of the present application, the thirteenth resistor R13 and the fourteenth resistor R14 are used to provide a bias voltage for the fifth switch unit Q5. That is, in the embodiment of the present application, the thirteenth resistor R13 and the fourteenth resistor R14 can also be replaced by circuits with corresponding functions.

[0068] In some embodiments, in the pulse activation circuit provided by the embodiments of the present application, the fifth switch unit Q5 includes an N-type MOS tube Q5.

[0069] In some embodiments, Figure 5Another structural schematic diagram of the pulse activation circuit provided in the embodiment of the present application is shown. Figure 5 As shown, the pulse activation circuit provided in the embodiment of the present application further includes a sixth switch unit Q6, a fifteenth resistor R15, a sixteenth resistor R16, a seventeenth resistor R17, and an eighteenth resistor R18.

[0070] The control end of the sixth switch unit Q6 is respectively connected to the first end of the fifteenth resistor R15 and the first end of the sixteenth resistor R16, the first end of the sixth switch unit Q6 is used for grounding and is connected to the second end of the sixteenth resistor R16, the second end of the sixth switch unit Q6 is respectively connected to the first end of the seventeenth resistor R17 and the first end of the eighteenth resistor R18, the second end of the fifteenth resistor R15 is respectively connected to the second delay unit C4 and the third switch branch, the second end of the seventeenth resistor R17 is connected to the voltage conversion unit to receive the power-on voltage output by the voltage conversion unit, and the second end of the eighteenth resistor R18 is connected to the main control module, and is used to output a feedback signal to the main control module after the sixth switch unit is turned on, so that the main control module outputs a self-holding signal according to the feedback signal.

[0071] Optionally, after the second switch branch is turned on, the bias voltage formed by the fifteenth resistor R15 and the sixteenth resistor R16 turns on the sixth switch unit Q6, thereby outputting a low-level signal to the main control module. After receiving the low-level signal, the main control module outputs a high-level self-holding signal, thereby controlling the main control module to output a self-holding signal.

[0072] In the embodiment of the present application, the fifteenth resistor R15 and the sixteenth resistor R16 are used to provide a bias voltage for the sixth switch unit Q6, the seventeenth resistor R17 is used to form a voltage, and the eighteenth resistor R18 is used as a sampling resistor to sample the feedback signal. That is to say, in the embodiment of the present application, the fifteenth resistor R15, the sixteenth resistor R16, the seventeenth resistor R17 and the eighteenth resistor R18 can also be replaced by circuits with corresponding functions.

[0073] In some embodiments, in the pulse activation circuit provided by the embodiments of the present application, the sixth switch unit Q6 includes an N-type MOS tube Q6.

[0074] It can be understood that, in the pulse activation circuit provided in the embodiment of the present application, when a MOS tube device is used as a switch unit, the control end of each switch unit is the gate of the MOS tube, the first end is the source of the MOS tube, and the second end is the drain of the MOS tube. In addition, because the source and drain of the MOS tube can be symmetrical in structure, the source and drain thereof can be indistinguishable in structure, that is, the MOS tube in the embodiment of the present application can use either a P-type MOS tube or an N-type MOS tube, but it should be clear that the conduction conditions of the P-type MOS tube and the N-type MOS tube are different, so when the MOS tube type in the circuit is replaced, the circuit structure for controlling the on-off of the MOS tube should also be replaced accordingly.

[0075] The pulse activation circuit provided in the embodiment of the present application realizes the activation of the power-on system in a pulse manner. It only needs to receive one frame of CAN signal to trigger the pulse to activate the system. The entire activation process does not require the participation of the CAN transceiver, thus avoiding the circuit cost brought by the CAN transceiver.

[0076] Furthermore, the pulse activation circuit provided in the present application electrically isolates the CAN signal from the pulse signal, and then uses the pulse signal to activate the power-on system. In this way, when the CAN signal is subjected to external abnormal high voltage, the power-on system will not be affected in any way, thereby improving the reliability of the operation of the power-on system.

[0077] The above contents are further detailed descriptions of the present application in combination with specific implementation methods, and it cannot be determined that the specific implementation of the present application is limited to these descriptions. For ordinary technicians in the technical field to which the present application belongs, several simple deductions or substitutions can be made without departing from the concept of the present application, which should be regarded as the protection scope of the present application.

Claims

1. A pulse activation circuit, characterized in that: include: A signal isolation module, used for receiving a CAN differential signal and generating a level signal electrically isolated from the CAN differential signal; A pulse generating module, connected to the signal isolating module, for receiving a CAN differential signal and short-circuiting the CAN differential signal after the level signal is generated, so that the level signal becomes a pulse signal; A power-on control module, used to connect to a power source and control the power source to power on the main control module according to the pulse signal; A power-on self-holding module, used to connect to the main control module and to the power-on control module, so as to receive a self-holding signal output by the main control module after power-on, so that the power-on control module controls the power supply to power on the main control module according to the self-holding signal; Wherein, the pulse generating module comprises a first switch unit, a first delay unit, a second resistor, a third resistor and a second diode; The control end of the first switch unit is respectively connected to the first end of the first delay unit, the first end of the second resistor, and the first end of the third resistor, the first end of the first switch unit is respectively connected to the second end of the first delay unit, the second end of the third resistor, and the low signal line in the CAN bus, and the second end of the first switch unit is connected to the signal isolation module; The anode of the second diode is used to connect to the high signal line in the CAN bus, and the cathode of the second diode is connected to the second end of the second resistor; The first delay unit is used to control the first switch unit to delay conduction, so as to short-circuit the CAN differential signal after the signal isolation module generates a level signal.

2. The pulse activation circuit according to claim 1, characterized in that: The signal isolation module includes a first resistor, a first diode and an optical coupler; The first end of the first resistor is used to connect to the high signal line in the CAN bus, and the second end is respectively connected to the cathode of the first diode, the anode input end of the optical coupler and the pulse generating module; The anode of the first diode is used to connect to the low signal line in the CAN bus and is connected to the cathode input terminal of the optical coupler; The output end of the optical coupler is connected to the power-on control module; The high signal line in the CAN bus is used to output the high level signal in the CAN differential signal, and the low signal line in the CAN bus is used to output the low level signal in the CAN differential signal.

3. The pulse activation circuit according to claim 1, characterized in that: The first delay unit includes a first capacitor.

4. The pulse activation circuit according to claim 1, characterized in that: The power-on control module includes a second switch branch, a third switch branch, a fourth switch branch, a second delay unit and a voltage conversion unit; The second switch branch is used to connect the power supply, and is respectively connected to the signal isolation module, the third switch branch and the second delay unit; The third switch branch is also connected to the second delay unit, the fourth switch branch and the power-on self-holding module respectively; The first end of the second delay unit is connected to the second switch branch and the third switch branch respectively, and the second end of the second delay unit is used to be grounded, so as to delay the disconnection of the third switch branch after the second switch branch is disconnected; The fourth switch branch is used to connect the power supply, and is also connected to the voltage conversion unit and the power-on self-holding module respectively, so as to control the power supply to supply power to the voltage conversion unit after being turned on; The voltage conversion unit is used to step down the voltage output by the power supply to provide a power-on voltage for the main control module.

5. The pulse activation circuit according to claim 4, characterized in that: The second switch branch includes a second capacitor, a third capacitor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a third diode and a second switch unit; The first end of the second capacitor is connected to the first end of the fourth resistor and the first end of the fifth resistor respectively, and the second end of the second capacitor is grounded; The second end of the fourth resistor is used for grounding, and the second end of the fifth resistor is connected to the signal isolation module; The first end of the third capacitor is respectively connected to the first end of the sixth resistor, the first end of the seventh resistor, the cathode of the third diode and the first end of the second switch unit, and the second end of the third capacitor is used to connect to the power supply and is connected to the second end of the sixth resistor; The second end of the seventh resistor is respectively connected to the anode of the third diode, the control end of the second switch unit and the signal isolation module; The first end of the eighth resistor is connected to the second end of the second switch unit, and the second end of the eighth resistor is connected to the second delay unit and the third switch branch respectively.

6. The pulse activation circuit according to claim 4, characterized in that: The third switch branch includes a third switch unit, a ninth resistor and a tenth resistor; The control end of the third switch unit is respectively connected to the first end of the ninth resistor and the first end of the tenth resistor, the first end of the third switch unit is respectively connected to the fourth switch branch and the power-on self-holding module, and the second end of the third switch unit is used for grounding; The second end of the ninth resistor is connected to the second delay unit and the second switch branch respectively, and the second end of the tenth resistor is grounded.

7. The pulse activation circuit according to claim 6, characterized in that: The fourth switch branch includes a fourth switch unit, an eleventh resistor, a twelfth resistor and a fourth diode; The control end of the fourth switch unit is respectively connected to the first end of the eleventh resistor, the first end of the twelfth resistor and the anode of the fourth diode, the first end of the fourth switch unit is connected to the voltage conversion unit, and the second end of the fourth switch unit is used to connect to the power supply and is respectively connected to the second end of the eleventh resistor and the cathode of the fourth diode; The second end of the twelfth resistor is connected to the third switch branch and the power-on self-holding module respectively.

8. The pulse activation circuit according to claim 1, characterized in that: The power-on self-holding module includes a fifth switch unit, a thirteenth resistor and a fourteenth resistor; The control end of the fifth switch unit is respectively connected to the first end of the thirteenth resistor and the first end of the fourteenth resistor, the first end of the fifth switch unit is connected to the power-on control module, and the second end of the fifth switch unit is used for grounding and connected to the second end of the fourteenth resistor; The second end of the thirteenth resistor is used to connect to the main control module.

9. The pulse activation circuit according to claim 4, characterized in that: Also includes a sixth switch unit, a fifteenth resistor, a sixteenth resistor, a seventeenth resistor, and an eighteenth resistor; The control end of the sixth switch unit is respectively connected to the first end of the fifteenth resistor and the first end of the sixteenth resistor, the first end of the sixth switch unit is used for grounding and connected to the second end of the sixteenth resistor, and the second end of the sixth switch unit is respectively connected to the first end of the seventeenth resistor and the first end of the eighteenth resistor; The second end of the fifteenth resistor is connected to the second delay unit and the third switch branch respectively, the second end of the seventeenth resistor is connected to the voltage conversion unit to receive the power-on voltage output by the voltage conversion unit, and the second end of the eighteenth resistor is connected to the main control module to output a feedback signal to the main control module after the sixth switch unit is turned on, so that the main control module outputs the self-holding signal according to the feedback signal.

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