A circuit and method for waking up vehicle-mounted equipment from ACC dormancy and deadlock

Abstract

The present invention discloses a circuit and method for waking up an in-vehicle device from ACC dormancy and dead state. The circuit comprises an ACC detection circuit, an MCU circuit, an analog switch, and a watchdog circuit. The ACC detection circuit is connected to the vehicle body to detect the ACC status. The input end of the MCU circuit is connected to the ACC detection circuit. The control end of the analog switch is connected to the ACC detection circuit to switch signals according to the ACC status. The output end of the MCU circuit is connected to the feeding end of the watchdog circuit. The reset signal output end of the watchdog circuit is connected to the first fixed end of the analog switch. The second fixed end of the analog switch is connected to a high-level signal. The reset end of the MCU circuit is connected to the active end of the analog switch, and the MCU circuit is reset according to the input of the reset end. The present invention controls the resetting of the MCU circuit by controlling the analog switch connected to the watchdog circuit to promptly wake up the in-vehicle device, thereby improving customer satisfaction.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle-mounted equipment, and in particular to a circuit and method for waking up an ACC dormant or dead system of a vehicle-mounted equipment. Background Art

[0002] With the development of science and technology, the application of electronic devices in the automotive field is becoming more and more extensive, and the application of on-board electronic control units is also increasing, which consumes a lot of car batteries. In order to avoid excessive consumption of car batteries by on-board electronic control units, some on-board electronic control units need to be able to enter a dormant state in a timely manner when not working. For example, when the ACC is in the OFF state, some electronic control units need to be turned off or enter a dormant state, and then triggered to enter the working state when the ACC is in the ON state. At present, it is common to encounter the problem of the MCU freezing after entering the dormant state when the ACC is in the OFF state. When the ACC is turned on, the MCU cannot be effectively awakened. The only way to solve the problem of not being able to wake up after the ACC freezes is to disconnect the main power supply of the vehicle body and then re-power it on to solve the problem of not being able to wake up after the ACC freezes. Disconnecting the main power supply of the vehicle body causes inconvenience to customers when using in-vehicle products, reducing customer satisfaction with the product. Summary of the Invention

[0003] The main purpose of the present invention is to provide a circuit and method for waking up the ACC dormant system of an in-vehicle device, which can reawaken the MCU without continuously turning off the main power of the vehicle body.

[0004] The present invention adopts the following technical solutions:

[0005] On the one hand, the present invention provides a vehicle-mounted device ACC dormancy and dead wake-up circuit, comprising: an ACC detection circuit, an MCU circuit, an analog switch and a watchdog circuit; the ACC detection circuit is connected to the vehicle body to detect the status of the ACC; the input end of the MCU circuit is connected to the ACC detection circuit to receive the status of the ACC; the control end of the analog switch is connected to the ACC detection circuit to switch signals in the signal chain according to the status of the ACC; the output end of the MCU circuit is connected to the dog feeding end of the watchdog circuit to send a dog feeding signal; the reset signal output end of the watchdog circuit is connected to the first fixed end of the analog switch; the second fixed end of the analog switch is connected to a high-level signal; the reset end of the MCU circuit is connected to the active end of the analog switch, and the MCU circuit performs a reset according to the input of the reset end.

[0006] Preferably, the circuit also includes: a power conversion circuit; the power conversion circuit is connected to the car body to convert the DC power output by the car body; the power conversion circuit is connected to the MCU circuit and the watchdog circuit to provide power.

[0007] Preferably, the DC power output by the automobile body is 24V; the DC power output by the power conversion circuit to the MCU circuit and the watchdog circuit is 3.3V or 5V.

[0008] Preferably, the analog switch is a single-pole double-throw switch.

[0009] Preferably, when the reset terminal input of the MCU circuit is at a high level, reset is not performed; when the reset terminal input of the MCU circuit is at a low level, reset is performed.

[0010] Preferably, when the state of ACC is ON, the movable end of the analog switch is connected to the first fixed end; when the state of ACC is OFF, the movable end of the analog switch is connected to the second fixed end.

[0011] Preferably, when the dog feeding end of the watchdog circuit receives a dog feeding signal, the reset signal output end of the watchdog circuit outputs a high level signal; when the dog feeding end of the watchdog circuit does not receive a dog feeding signal within a preset time, the reset signal output end of the watchdog circuit outputs a low level signal.

[0012] On the other hand, the present invention provides a vehicle-mounted device ACC dormancy crash wakeup method, based on the vehicle-mounted device ACC dormancy crash wakeup circuit, comprising:

[0013] When the state of ACC changes from OFF to ON, the active end of the analog switch is connected to the first fixed end; if the MCU circuit crashes while ACC is OFF, the MCU circuit does not output a dog feeding signal to the dog feeding end of the watchdog circuit, and the reset signal output end of the watchdog circuit connected to the first fixed end sends a low-level signal to reset the MCU circuit, thereby causing the MCU circuit to re-enter the normal working mode.

[0014] Preferably, the method further comprises:

[0015] If the MCU circuit does not crash during the period when ACC is OFF, the input end of the MCU circuit detects a level jump event of ACC, triggering the MCU circuit to enter a normal working mode; the MCU circuit outputs a dog feeding signal to the dog feeding end of the watchdog circuit; the reset signal output end of the watchdog circuit connected to the first fixed end sends a high-level signal to the MCU circuit, and the MCU circuit does not reset.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The present invention discloses a circuit and method for waking up an on-board device from an ACC dormancy freeze. By enabling an analog switch connected to a watchdog circuit via an ACC signal, the circuit controls a watchdog reset signal connected to an MCU reset circuit, thereby promptly waking up an on-board device that has frozen during ACC dormancy. This circuit solves the problem of existing on-board devices requiring disconnection of the vehicle's main power supply and subsequent re-powering upon freezing during ACC dormancy to ensure normal operation of the device. This improves customer satisfaction with on-board products.

[0018] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention so that it can be implemented in accordance with the contents of the specification, and to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are listed below.

[0019] Based on the following detailed description of specific embodiments of the present invention in conjunction with the accompanying drawings, those skilled in the art will become more aware of the above and other objects, advantages and features of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 1 is a circuit diagram of the present invention. DETAILED DESCRIPTION

[0021] To make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0022] See also Figure 1 As shown, on the one hand, the present invention provides a vehicle-mounted device ACC dormancy and dead wake-up circuit, comprising: an ACC detection circuit 10, an MCU circuit 20, an analog switch 30, and a watchdog circuit 40; the ACC detection circuit 10 is connected to a vehicle body 60 to detect the state of the ACC; an input terminal GPIO1 of the MCU circuit 20 is connected to the ACC detection circuit 10 to receive the ACC state; a control terminal IN of the analog switch 30 is connected to the ACC detection circuit 10 to switch signals in a signal chain according to the ACC state; an output terminal GPIO2 of the MCU circuit 20 is connected to a watchdog feeding terminal WDI of the watchdog circuit 40 to send a watchdog feeding signal; a reset signal output terminal RESET of the watchdog circuit 40 is connected to a first fixed terminal NC of the analog switch 30; a second fixed terminal NO of the analog switch 30 is connected to a high-level signal VDD; a reset terminal RESET of the MCU circuit 20 is connected to a moving terminal COM of the analog switch 30, and the MCU circuit 20 is reset according to the input of the reset terminal RESET.

[0023] Furthermore, the circuit also includes: a power conversion circuit 50; the power conversion circuit 50 is connected to the automobile body 60 to convert the DC power output by the automobile body 60; the power conversion circuit 50 is connected to the MCU circuit 20 and the watchdog circuit 40 to provide power.

[0024] Specifically, the DC power output by the automobile body 60 is 24V; the DC power output by the power conversion circuit 50 to the MCU circuit 20 and the watchdog circuit 40 is 3.3V or 5V.

[0025] Furthermore, the analog switch 30 is a single-pole double-throw switch, which includes a control terminal IN, a dynamic terminal COM, a first static terminal NC, and a second static terminal NO.

[0026] When the state of ACC is ON, the moving terminal COM of the single-pole double-throw switch is connected to the first fixed terminal NC; when the state of ACC is OFF, the moving terminal COM of the analog switch 30 is connected to the second fixed terminal NO.

[0027] Furthermore, the MCU circuit 20 is a single-chip microcomputer system with a sleep function, including an MCU controller. A low-level reset triggers a reset at the MCU reset terminal RESET. That is, when the MCU reset terminal RESET input is high, the MCU circuit 20 does not reset; when the MCU reset terminal RESET input is low, the MCU circuit 20 resets.

[0028] Furthermore, the watchdog circuit 40 is a circuit having a watchdog feeding terminal WDI and a reset signal output terminal RESET. When the watchdog feeding terminal WDI of the watchdog circuit 40 receives a watchdog feeding signal within a specified time, the reset signal output terminal RESET of the watchdog circuit 40 outputs a high-level signal. When the watchdog feeding terminal WDI of the watchdog circuit 40 does not receive a watchdog feeding signal within the specified time, the reset signal output terminal RESET of the watchdog circuit 40 outputs a low-level signal, triggering the MCU circuit 20 to reset.

[0029] On the other hand, the present invention provides a vehicle-mounted device ACC dormancy crash wakeup method, based on the vehicle-mounted device ACC dormancy crash wakeup circuit, comprising:

[0030] When the state of ACC changes from OFF to ON, the active terminal COM of the analog switch 30 is connected to the first fixed terminal NC. If the MCU circuit 20 crashes while ACC is OFF, the MCU circuit 20 does not output a feeding signal to the feeding terminal WDI of the watchdog circuit 40. The reset signal output terminal RESET of the watchdog circuit 40 connected to the first fixed terminal NC sends a low-level signal to reset the MCU circuit 20, thereby causing the MCU circuit 20 to re-enter the normal operating mode.

[0031] Preferably, the method further comprises:

[0032] If the MCU circuit 20 does not crash during the period when ACC is OFF, the input terminal GPIO1 of the MCU circuit 20 detects a level jump event of ACC, triggering the MCU circuit 20 to enter a normal working mode; the MCU circuit 20 outputs a dog feeding signal to the dog feeding terminal WDI of the watchdog circuit 40; the reset signal output terminal RESET of the watchdog circuit 40 connected to the first fixed terminal NC sends a high level signal to the MCU circuit 20, and the MCU circuit 20 does not reset.

[0033] Specifically, when ACC is ON, the MCU circuit 20 operates in normal mode, the active end COM of the analog switch 30 is connected to the first fixed end NC, the MCU circuit 20 continuously feeds the watchdog circuit 40, the reset signal output end RESET of the watchdog circuit 40 outputs a high level, the reset end RESET of the MCU circuit 20 continuously outputs a high level, no reset event is generated, and the system operates normally; when the MCU circuit 20 fails to feed the watchdog circuit 40 within the specified time interval (the system crashes), the reset signal output end RESET of the watchdog circuit 40 outputs a low level, the reset end RESET of the MCU circuit 20 outputs a low level, triggering the reset of the MCU circuit 20, and allowing the system to re-enter the normal operating state.

[0034] When ACC is OFF, the MCU circuit 20 operates in sleep mode. The active terminal COM and the second, non-active terminal NO of the analog switch 30 are connected. The reset terminal RESET of the MCU circuit 20 is connected to a continuous high-level VDD signal (VDD = 3.3V). No reset event occurs, and the system remains in sleep mode. During sleep, the MCU circuit 20 cannot feed the watchdog. The watchdog circuit 40 will continue to send a reset signal. However, since the analog switch 30 does not receive the watchdog reset signal when ACC is OFF, the MCU circuit 20 will not reset.

[0035] When ACC is ON again, if the MCU circuit 20 does not freeze during the ACC OFF period, the MCU circuit 20 can detect the level jump event of the input terminal GPIO1, triggering the MCU circuit 20 to enter the normal working mode; if the MCU circuit 20 freezes during the ACC OFF period and cannot be reset through the input terminal GPIO1 detection function, the MCU circuit 20 does not feed the watchdog because the active terminal COM and the first fixed terminal NC of the analog switch 30 are connected when ACC is ON. The watchdog circuit 40 will send a low-level signal to reset the MCU circuit 20, thereby causing the system to re-enter the normal working mode.

[0036] The above is only a specific implementation of the present invention, but the design concept of the present invention is not limited to this. Any non-substantial changes to the present invention using this concept shall be deemed as an infringement of the protection scope of the present invention.

Claims

1. A vehicle-mounted device ACC sleep and freeze wake-up circuit, characterized in that: include: ACC detection circuit, MCU circuit, analog switch and watchdog circuit; The ACC detection circuit is connected to the vehicle body to detect the state of the ACC; The input end of the MCU circuit is connected to the ACC detection circuit to receive the status of ACC; the control end of the analog switch is connected to the ACC detection circuit to switch the signal in the signal chain according to the status of ACC; the output end of the MCU circuit is connected to the feeding end of the watchdog circuit to send a feeding signal; the reset signal output end of the watchdog circuit is connected to the first fixed end of the analog switch; the second fixed end of the analog switch is connected to a high-level signal; the reset end of the MCU circuit is connected to the active end of the analog switch, and the MCU circuit is reset according to the input of the reset end; when the status of ACC is ON, the active end of the analog switch is connected to the first fixed end, and the reset signal output end of the watchdog circuit is connected to the reset end of the MCU circuit; when the status of ACC is OFF, the active end of the analog switch is connected to the second fixed end, and the reset end of the MCU circuit continues to receive a high-level signal.

2. The vehicle-mounted device ACC sleep and freeze wake-up circuit according to claim 1, characterized in that: Also includes: A power conversion circuit; the power conversion circuit is connected to the vehicle body to convert the DC power output by the vehicle body; The power conversion circuit is connected to the MCU circuit and the watchdog circuit to supply power.

3. The vehicle-mounted device ACC sleep and freeze wake-up circuit according to claim 2, characterized in that: The DC power output by the automobile body is 24V; the DC power output by the power conversion circuit to the MCU circuit and the watchdog circuit is 3.3V or 5V.

4. The vehicle-mounted device ACC sleep and freeze wake-up circuit according to claim 1, characterized in that: The analog switch is a single-pole double-throw switch.

5. The vehicle-mounted device ACC sleep and freeze wake-up circuit according to claim 1, characterized in that: When the reset terminal input of the MCU circuit is at a high level, reset is not performed; when the reset terminal input of the MCU circuit is at a low level, reset is performed.

6. The vehicle-mounted device ACC sleep and freeze wake-up circuit according to claim 1, characterized in that: When the dog feeding end of the watchdog circuit receives a dog feeding signal, the reset signal output end of the watchdog circuit outputs a high level signal; when the dog feeding end of the watchdog circuit does not receive a dog feeding signal within a preset time, the reset signal output end of the watchdog circuit outputs a low level signal.

7. A method for waking up an in-vehicle device ACC from dormancy, characterized in that: The vehicle-mounted device ACC sleep and freeze wake-up circuit according to any one of claims 1 to 6 comprises: When the state of ACC changes from OFF to ON, the active end of the analog switch is connected to the first fixed end; if the MCU circuit crashes while ACC is OFF, the MCU circuit does not output a dog feeding signal to the dog feeding end of the watchdog circuit, and the reset signal output end of the watchdog circuit connected to the first fixed end sends a low-level signal to reset the MCU circuit, thereby causing the MCU circuit to re-enter the normal working mode.

8. The vehicle-mounted device ACC sleep and dead wake-up method according to claim 7 is characterized in that: The method further comprises: If the MCU circuit does not crash during the period when ACC is OFF, the input end of the MCU circuit detects a level jump event of ACC, triggering the MCU circuit to enter a normal working mode; the MCU circuit outputs a dog feeding signal to the dog feeding end of the watchdog circuit; the reset signal output end of the watchdog circuit connected to the first fixed end sends a high-level signal to the MCU circuit, and the MCU circuit does not reset.

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