Awakening control circuit based on CAN bus and electronic equipment

Abstract

The utility model relates to the technical field of wake-up circuits, in particular to a wake-up control circuit based on a CAN bus and electronic equipment. Comprising a CAN control module, a CAN wake-up module and an MCU. The first input end and the second input end of the CAN control module are connected with an external differential signal source and are used for receiving differential signals; the first output end of the CAN control module is connected with the first input end of the CAN wake-up module, and the CAN control module is used for sending a first level signal to start the CAN wake-up module if the CAN control module does not work; the first output end of the CAN control module is connected with the first input end of the CAN wake-up module, the second output end of the CAN control module is connected with the second input end of the CAN wake-up module, the third output end of the CAN control module is connected with the third input end of the CAN wake-up module, and the output end of the CAN wake-up module is connected with the input end of the MCU and used for sending a wake-up signal to the wake-up end of the MCU through the CAN wake-up module in the starting state according to the differential signal. According to the invention, the circuit can be awakened without depending on an external awakening signal source, so that the reliability and convenience of the circuit are improved.

Description

Technical Field

[0001] The present application relates to the technical field of wake-up circuits, and in particular to a wake-up control circuit and electronic equipment based on a CAN bus. Background Art

[0002] The CAN (Controller Area Network) bus is a serial communication protocol widely used in automotive and industrial automation. It offers high reliability, strong anti-interference capabilities, and the ability to transmit data over long distances. However, in modern electronic systems, it is often necessary to wake up dormant circuits based on external events or conditions to achieve energy conservation and intelligent control. Therefore, current mechanisms for waking up CAN circuits typically rely on external wake-up signal sources, including but not limited to buttons, switches, or timing circuits. These methods may require manual intervention or have distance limitations, impacting the reliability and convenience of the wake-up circuits.

[0003] Therefore, how to wake up the circuit without relying on an external wake-up signal source, thereby improving the reliability and convenience of the circuit, is a technical problem that needs to be solved urgently. Utility Model Content

[0004] In order to overcome the shortcomings of the prior art, the present application provides a wake-up control circuit and electronic equipment based on the CAN bus, so as to realize the circuit wake-up without relying on an external wake-up signal source, thereby improving the reliability and convenience of the circuit.

[0005] The technical solution adopted by this application to solve its technical problems is:

[0006] In a first aspect, the present application provides a wake-up control circuit based on a CAN bus, comprising: a CAN control module, a CAN wake-up module, and an MCU;

[0007] The first input terminal and the second input terminal of the CAN control module are connected to an external differential signal source, and are used to receive the differential signal output by the differential signal source;

[0008] The first output terminal of the CAN control module is connected to the first input terminal of the CAN wake-up module, and is used to send a first level signal to start the CAN wake-up module if the CAN control module is not working;

[0009] The second output end of the CAN control module is connected to the second input end of the CAN wake-up module, the third output end of the CAN control module is connected to the third input end of the CAN wake-up module, and the output end of the CAN wake-up module is connected to the input end of the MCU, and is used to send a wake-up signal to the wake-up end of the MCU through the CAN wake-up module in the startup state according to the differential signal.

[0010] Optionally, the CAN control module includes: a CAN chip, a first resistor, a second resistor and a third resistor;

[0011] The sleep pin of the CAN chip is connected to the first input terminal of the CAN wake-up module;

[0012] The high-bit pin of the CAN chip is connected to one end of the first resistor, one end of the third resistor and the second input end of the CAN wake-up module, and the other end of the first resistor is connected to the high-bit signal input end of the differential signal source;

[0013] The low-order pin of the CAN chip is connected to one end of the second resistor, the other end of the third resistor and the third input end of the CAN wake-up module, and the other end of the second resistor is connected to the low-order signal input end of the differential signal source.

[0014] Optionally, the CAN control module further includes: an electrostatic protection diode;

[0015] The anode of the electrostatic protection diode is connected to the connection point of the first resistor and the third resistor, and the cathode is connected to the connection point of the second resistor and the third resistor;

[0016] The ground terminal of the electrostatic protection diode is grounded.

[0017] Optionally, the CAN wake-up module includes: a transistor, an optocoupler, a fourth resistor and a fifth resistor;

[0018] The base of the transistor is connected to the sleep pin of the CAN chip, the emitter of the transistor is connected to the connection point of the second resistor and the third resistor, and the collector of the transistor is connected to the second pin of the optocoupler;

[0019] The first pin of the optocoupler is connected to one end of the fourth resistor, and the other end of the fourth resistor is connected to the connection point of the first resistor and the third resistor;

[0020] The third pin of the optocoupler is connected to one end of the fifth resistor and the wake-up end of the MCU, and the other end of the fifth resistor is connected to an external DC signal source;

[0021] The fourth pin of the optocoupler is grounded.

[0022] Optionally, the model of the CAN chip is SIT1042T / 3.

[0023] Optionally, the model of the electrostatic protection diode is NUP2105L.

[0024] Optionally, the model of the transistor is PDTC124ET.

[0025] Optionally, the model of the optocoupler is PS2801.

[0026] In a second aspect, the present application provides an electronic device equipped with the above-mentioned CAN bus-based wake-up control circuit.

[0027] The beneficial effects of this application are as follows: when the device is not working, the MCU enters a dormant state. At this time, the CAN control module is not working and sends a level signal to the CAN wake-up module through its first output terminal to activate the CAN wake-up module. In this case, if the first input terminal and the second input terminal of the CAN control module receive a differential signal output by an external differential signal source, the potential difference of the differential signal can control the CAN wake-up module to send a wake-up signal to the MCU through its output terminal. After the MCU receives the wake-up signal, the circuit wakes up. By adopting the above technical solution, the circuit can be woken up without relying on an external wake-up signal source, thereby improving the reliability and convenience of the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a module diagram of a CAN bus-based wake-up control circuit provided in an embodiment of the present application;

[0029] Figure 2 This is a circuit schematic diagram of a CAN bus-based wake-up control circuit provided in an embodiment of the present application. DETAILED DESCRIPTION

[0030] The present application is further described below with reference to the accompanying drawings and examples.

[0031] The following will clearly and completely describe the concept, specific structure and technical effects of this application in combination with the embodiments and drawings, so as to fully understand the purpose, characteristics and effects of this application. Obviously, the described embodiments are only part of the embodiments of this application, not all of them. Based on the embodiments of this application, other embodiments obtained by those skilled in the art without creative work are within the scope of protection of this application. In addition, all the connection / connection relationships involved in the patent do not refer to the direct connection of components, but refer to the formation of a better connection structure by adding or reducing connection accessories according to the specific implementation situation. The various technical features created in this application can be combined interactively without conflicting with each other.

[0032] Reference Figure 1 , Figure 1 This is a module diagram of a CAN bus-based wake-up control circuit provided in an embodiment of the present application, including a CAN control module, a CAN wake-up module, and an MCU. Specifically:

[0033] The first output end of the CAN control module is connected to the first input end of the CAN wake-up module, and is used to send a first level signal to start the CAN wake-up module if the CAN control module is not working.

[0034] Specifically, when the device is not working, the MCU enters a sleep state. At this time, the CAN control module is not working. The MCU sends a first level signal to the CAN wake-up module through its first output terminal and the first input terminal of the CAN wake-up module to activate the CAN wake-up module. In the embodiment of the present application, the first level signal is a high level signal.

[0035] The first input terminal and the second input terminal of the CAN control module are connected to an external differential signal source, and are used to receive the differential signal output by the differential signal source.

[0036] Specifically, the first input terminal of the CAN control module is connected to the high-order data line of the differential signal source, and the second input terminal is connected to the low-order data line of the differential signal source, which together constitute a differential signal. There is a potential difference between the high-order signal and the low-order signal.

[0037] The second output end of the CAN control module is connected to the second input end of the CAN wake-up module, the third output end of the CAN control module is connected to the third input end of the CAN wake-up module, and the output end of the CAN wake-up module is connected to the input end of the MCU, and is used to send a wake-up signal to the wake-up end of the MCU through the CAN wake-up module in the startup state according to the differential signal.

[0038] Specifically, the second output terminal of the CAN control module is connected to the second input terminal of the CAN wake-up module to transmit the high-level signal to the CAN wake-up module; similarly, the low-level signal is transmitted to the CAN wake-up module through the third input terminal of the CAN wake-up module, thereby forming a potential difference between the two ends. The CAN wake-up module is provided with an optocoupler, and the optocoupler is provided with a switching device. The switching device receives the start signal sent by the above-mentioned CAN control module through the first output terminal, thereby turning on the internal optocoupler. Then, based on the conduction of the internal optocoupler, the output terminal of the CAN wake-up module outputs a low-level signal to the wake-up terminal of the MCU, so that the MCU is awakened, thereby completing the circuit wake-up.

[0039] Further, refer to Figure 2 , Figure 2 This is a circuit schematic diagram of a CAN bus-based wake-up control circuit provided in an embodiment of the present application. It is a specific embodiment of each module in the above-mentioned CAN bus-based wake-up control circuit. Each module is described in detail below:

[0040] About CAN control module: The CAN control module includes: CAN chip U12, a first resistor R18, a second resistor R23 and a third resistor R22;

[0041] The sleep pin STB of the CAN chip U12 is connected to the first input terminal of the CAN wake-up module;

[0042] The high-bit pin of the CAN chip U12 is connected to one end of the first resistor R18, one end of the third resistor R22 and the second input end of the CAN wake-up module, and the other end of the first resistor R18 is connected to the high-bit signal input end of the differential signal source;

[0043] The low-order pin of the CAN chip U12 is connected to one end of the second resistor R23, the other end of the third resistor R22 and the third input end of the CAN wake-up module, and the other end of the second resistor R23 is connected to the low-order signal input end of the differential signal source.

[0044] Specifically, the sleep pin STB of the CAN chip U12 is pulled low when it is working normally, thereby turning off the CAN wake-up module. In this state, the CAN wake-up module is not started; when the corresponding electronic device enters the sleep state, the sleep pin STB of the CAN chip U12 is pulled high, thereby turning on the CAN wake-up module. Then, determine whether there is a differential signal between the high-order pin and the low-order pin of the CAN chip U12. The high-order signal in the differential signal is output to the high-order pin through the first resistor R18, and the low-order signal is output to the low-order pin through the second resistor R23. The first resistor R18 and the second resistor R23 play a current limiting role. A third resistor R22 is also incorporated between the first resistor R18 and the second resistor R23. The potential sampling between the third resistor R22 and the first resistor R18 is connected to the second input end of the CAN wake-up module, and the potential sampling between the third resistor R22 and the second resistor R23 is connected to the third input end of the CAN wake-up module. When a differential signal exists, there is a potential difference between the second input end and the third input end of the CAN wake-up module, thereby triggering the CAN wake-up module to send a wake-up signal to the MCU through its output end.

[0045] In the embodiment of the present application, the model of the CAN chip U12 is SIT1042T / 3.

[0046] Furthermore, the CAN control module also includes an electrostatic protection diode U27;

[0047] The anode of the electrostatic protection diode U27 is connected to the connection point of the first resistor R18 and the third resistor R22, and the cathode is connected to the connection point of the second resistor R23 and the third resistor R22;

[0048] The ground terminal of the electrostatic protection diode U27 is grounded.

[0049] Specifically, the anode is the positive pole of the electrostatic protection diode U27, which is used to connect to the signal line that needs to be protected. Under normal working conditions, the current flows from the anode to the cathode; the cathode is the negative pole of the diode, which is usually connected to the negative end of the power supply. In the circuit, the cathode is responsible for directing the overloaded current to the negative end of the power supply to protect other components; the grounding end is the protective ground of the diode, which is used to direct the overloaded current into the ground to prevent damage to the circuit.

[0050] In the embodiment of the present application, the model of the electrostatic protection diode U27 is NUP2105L.

[0051] About CAN wake-up module: The CAN wake-up module includes transistor Q6, optocoupler U7, fourth resistor R67 and fifth resistor R19;

[0052] The base of the transistor Q6 is connected to the sleep pin STB of the CAN chip U12, the emitter of the transistor Q6 is connected to the connection point of the second resistor R23 and the third resistor R22, and the collector of the transistor Q6 is connected to the second pin of the optocoupler U7.

[0053] Specifically, in combination with the above explanation, it can be seen that when the device is working normally, the sleep pin STB of the CAN chip U12 is pulled high. Since the transistor Q6 used in this application is an NPN transistor Q6, in this case the transistor Q6 is turned on, and the second pin of the optocoupler U7 is turned on through the collector, emitter, and the connection point of the second resistor R23 and the third resistor R22 (i.e., CAN1_L1) of the transistor Q6.

[0054] The first pin of the optocoupler U7 is connected to one end of the fourth resistor R67 , and the other end of the fourth resistor R67 is connected to the connection point of the first resistor R18 and the third resistor R22 .

[0055] Specifically, the connection point between the first resistor R18 and the third resistor R22, i.e., the potential CAN1_H1, is connected to the first pin of the optocoupler U7 through the fourth resistor R67, wherein the fourth resistor R67 functions as a current limiting protection circuit.

[0056] The third pin of the optocoupler U7 is connected to one end of the fifth resistor R19 and the wake-up end of the MCU, and the other end of the fifth resistor R19 is connected to the external DC signal source 3V3;

[0057] The fourth pin of the optocoupler U7 is grounded.

[0058] Specifically, when transistor Q6 is turned on and a differential signal is present, the signal is output from point CAN1_H1 through the fourth resistor R67, the photodiode inside optocoupler U7, and transistor Q6 to point CAN1_L1, thereby connecting the third and fourth pins of optocoupler U7. In this case, the external DC signal source 3V3 passes through the fifth resistor R19 and optocoupler U7 to ground, forming a loop, which lowers the potential at point CAN_DET. This low potential triggers the MCU's wake-up pin, completing circuit wake-up. M1 in the figure is a simplified model of the MCU.

[0059] In the embodiment of the present application, the model of the transistor Q6 is PDTC124ET, and the model of the optocoupler U7 is PS2801.

[0060] In a second aspect, the present application provides an electronic device equipped with the above-mentioned CAN bus-based wake-up control circuit.

[0061] The above is a specific description of the preferred implementation of the present application, but the invention of the present application is not limited to the described embodiments. Technical personnel familiar with the art can also make various equivalent modifications or substitutions without violating the spirit of the present application. These equivalent modifications or substitutions are all included in the scope defined by the claims of the present application.

Claims

1. A wake-up control circuit based on the CAN bus, characterized in that: include: CAN control module, CAN wake-up module and MCU; The first input terminal and the second input terminal of the CAN control module are connected to an external differential signal source, and are used to receive the differential signal output by the differential signal source; The first output terminal of the CAN control module is connected to the first input terminal of the CAN wake-up module, and is used to send a first level signal to start the CAN wake-up module if the CAN control module is not working; The second output end of the CAN control module is connected to the second input end of the CAN wake-up module, the third output end of the CAN control module is connected to the third input end of the CAN wake-up module, and the output end of the CAN wake-up module is connected to the input end of the MCU, and is used to send a wake-up signal to the wake-up end of the MCU through the CAN wake-up module in the startup state according to the differential signal.

2. The CAN bus-based wake-up control circuit according to claim 1, characterized in that: The CAN control module includes: a CAN chip, a first resistor, a second resistor and a third resistor; The sleep pin of the CAN chip is connected to the first input terminal of the CAN wake-up module; The high-bit pin of the CAN chip is connected to one end of the first resistor, one end of the third resistor and the second input end of the CAN wake-up module, and the other end of the first resistor is connected to the high-bit signal input end of the differential signal source; The low-order pin of the CAN chip is connected to one end of the second resistor, the other end of the third resistor and the third input end of the CAN wake-up module, and the other end of the second resistor is connected to the low-order signal input end of the differential signal source.

3. The CAN bus-based wake-up control circuit according to claim 2, characterized in that: The CAN control module further includes: an electrostatic protection diode; The anode of the electrostatic protection diode is connected to the connection point of the first resistor and the third resistor, and the cathode is connected to the connection point of the second resistor and the third resistor; The ground terminal of the electrostatic protection diode is grounded.

4. The CAN bus-based wake-up control circuit according to claim 2, characterized in that: The CAN wake-up module includes: a transistor, an optical coupler, a fourth resistor and a fifth resistor; The base of the transistor is connected to the sleep pin of the CAN chip, the emitter of the transistor is connected to the connection point of the second resistor and the third resistor, and the collector of the transistor is connected to the second pin of the optocoupler; The first pin of the optocoupler is connected to one end of the fourth resistor, and the other end of the fourth resistor is connected to the connection point of the first resistor and the third resistor; The third pin of the optocoupler is connected to one end of the fifth resistor and the wake-up end of the MCU, and the other end of the fifth resistor is connected to an external DC signal source; The fourth pin of the optocoupler is grounded.

5. The CAN bus-based wake-up control circuit according to claim 2, characterized in that: The model of the CAN chip is SIT1042T / 3.

6. The CAN bus-based wake-up control circuit according to claim 3, characterized in that: The model of the electrostatic protection diode is NUP2105L.

7. The CAN bus-based wake-up control circuit according to claim 4, characterized in that: The model of the transistor is PDTC124ET.

8. The CAN bus-based wake-up control circuit according to claim 4, characterized in that: The model of the optocoupler is PS2801.

9. An electronic device, characterized in that: The device is equipped with a CAN bus-based wake-up control circuit as described in any one of claims 1 to 8.

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