LIMPHOME circuit, control device and automobile

Abstract

The embodiments of the present invention provide a LIMPHOME circuit, a control device and a car, and relate to the field of electronic control technology. The LIMPHOME circuit includes: a state latch unit, which is used to output a control signal of a corresponding level state according to the level state of a first input signal and the level state of a second input signal, and when the combination of the level state of the first input signal and the level state of the second input signal is a first level state combination, the level state of the control signal currently output is maintained; a signal control unit, which is used to switch the combination of the level state of the first input signal and the level state of the second input signal to the input state latch unit after the second level state combination in response to an interrupt signal; the level state is a low level or a high level. When the output state is maintained, the present invention can change the level state of the output control signal through an interrupt signal to interrupt the output state maintenance, thereby avoiding the consumption of battery power.

Description

Technical Field

[0001] The present invention relates to the field of electronic control technology, and in particular to a LIMPHOME circuit, a control device and a car. Background Art

[0002] LIMPHOME (limp home mode) means that when the electronic control equipment of the car fails, when the functional module or sensor signal fails, the functional module can still complete the basic functions, so that the car can still run at the minimum required performance level. The functional essence of LIMP HOME means that when the electronic control system of the vehicle has a problem, the control logic can make judgments based on the corresponding conditions and arrange another set of control levels so that the load that must be controlled runs according to the established logic.

[0003] There must not be any abnormalities during the reset, restart or freeze of the controller (MCU), otherwise it will affect the driver's safety. For example, the engine cannot suddenly shut down during driving, and the headlights cannot suddenly go out during night driving. The maintenance of these output states requires a circuit independent of the MCU, namely the LIMPHOME circuit.

[0004] However, the existing LIMPHOME circuit cannot shut down the output when the system crashes. Once the system crashes at night, the system's external output will continue to supply power until the battery is exhausted, leaving a great safety hazard. Summary of the invention

[0005] The purpose of the embodiments of the present invention is to provide a LIMPHOME circuit, a control device and a car to solve the problem that the existing LIMPHOME circuit cannot turn off the output when the system crashes.

[0006] In order to achieve the above object, in a first aspect of the present invention, a LIMPHOME circuit is provided, the circuit comprising:

[0007] a state latch unit, configured to output a control signal of a corresponding level state according to a level state of a first input signal and a level state of a second input signal, and to maintain a level state of a currently output control signal when a combination of a level state of the first input signal and a level state of the second input signal is a first level state combination;

[0008] A signal control unit connected to the state latch unit, for switching the combination of the level state of the first input signal and the level state of the second input signal to a second level state combination and inputting the combination into the state latch unit in response to an interrupt signal;

[0009] The level state is a low level or a high level.

[0010] Optionally, the state latch unit is a RS trigger.

[0011] Optionally, the signal control unit includes:

[0012] A logic gate subunit and an interrupt signal control subunit connected to the logic gate subunit;

[0013] The interrupt signal control subunit controls the logic gate subunit to switch the combination of the level state of the first input signal and the level state of the second input signal to the second level state combination in response to the interrupt signal.

[0014] Optionally, the logic gate subunit includes:

[0015] A first logic gate, a second logic gate and a third logic gate;

[0016] The first input end of the first logic gate is connected to the output end of the interrupt signal control subunit, the second input end of the first logic gate is used to receive the first input signal, and the output end of the first logic gate is connected to the set end of the RS trigger;

[0017] The input end of the second logic gate is connected to the output end of the interrupt signal control subunit and the first input end of the first logic gate, the output end of the second logic gate is connected to the first input end of the third logic gate, the second input end of the third logic gate is used to receive the second input signal, and the output end of the third logic gate is connected to the reset end of the RS trigger;

[0018] The first logic gate is an AND gate, the second logic gate is a NOT gate, and the third logic gate is an OR gate.

[0019] Optionally, the interrupt signal control subunit includes:

[0020] A first switch and a voltage dividing resistor;

[0021] The first end of the first switch is grounded, the second end of the first switch is connected to the second end of the voltage divider resistor and connected to the first input end of the first logic gate and the input end of the second logic gate, and the first end of the voltage divider resistor is connected to a reference signal.

[0022] Optionally, the first switch is a reset switch.

[0023] Optionally, the reference signal is a high level signal.

[0024] Optionally, the first level state combination is that the level state of the first input signal is a low level, and the level state of the second input signal is a low level;

[0025] The second level state combination is that the level state of the first input signal is a low level, and the level state of the second input signal is a high level.

[0026] In a second aspect of the present invention, a control device is provided, comprising:

[0027] The LIMPHOME circuit described above; and

[0028] A controller is provided for generating the first input signal and the second input signal.

[0029] In a third aspect of the present invention, a car is provided, comprising the above-mentioned control device.

[0030] The above technical solution of the present invention realizes the output state retention when the system is reset or the system crashes through the state latch unit. At the same time, when the state latch unit executes the output state retention, the control unit can change the level state of the input signal through the interrupt signal to change the level state of the control signal output by the state latch unit, thereby interrupting the output state retention of the state latch unit to shut down the system power supply when necessary to avoid battery power consumption.

[0031] Other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the embodiments of the present invention, but do not constitute a limitation on the embodiments of the present invention. In the accompanying drawings:

[0033] Figure 1 Schematic diagram of the circuit structure of the LIMPHOME circuit provided in the preferred embodiment of the present invention;

[0034] Figure 2 is a circuit diagram of an existing LIMPHOME circuit provided in a preferred embodiment of the present invention;

[0035] Figure 3 4 is a circuit diagram of a LIMPHOME circuit provided in a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0036] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0037] like Figure 1As shown, in a first aspect of the present invention, a LIMPHOME circuit is provided, the LIMPHOME circuit comprising:

[0038] A state latch unit is used to output a control signal of a corresponding level state according to the level state of a first input signal and the level state of a second input signal, and when the combination of the level state of the first input signal and the level state of the second input signal is a first level state combination, maintain the level state of the currently output control signal; a signal control unit connected to the state latch unit is used to respond to an interrupt signal and switch the combination of the level state of the first input signal and the level state of the second input signal to the second level state combination and then input to the state latch unit; the level state is a low level or a high level.

[0039] In this way, this embodiment realizes the output state retention during system reset and crash through the state latch unit. At the same time, when the state latch unit executes the output state retention, the control unit can change the level state of the input signal through the interrupt signal to change the level state of the control signal output by the state latch unit, thereby interrupting the output state retention of the state latch unit to shut down the system power supply when necessary to avoid battery power consumption.

[0040] like Figure 2 As shown, the existing LIMPHOME circuit is usually implemented using an RS trigger to ensure that the previous output state remains unchanged when the system crashes or restarts. In the automotive electronic control system, an MCU is usually used as the controller of the electronic control system, and the two I / O ports of the MCU are used as output terminals to be connected to the set terminal S and the reset terminal R of the RS trigger respectively, so as to control the level state of the S terminal and the R terminal of the RS trigger through the MCU, thereby controlling the level state of the control signal output by the RS trigger. The truth table of the RS trigger is shown in Table 1, where 1 represents a high level and 0 represents a low level.

[0041]

[0042] Table 1

[0043] In the existing LIMPHOME circuit, the on-off between the battery and the load is usually controlled by a MOS tube, so that the output end of the RS trigger is connected to the MOS tube, for example, the output end of the RS trigger is connected to the gate of an N-channel MOS tube, the source of the MOS tube is grounded, and its drain is connected to the first end of a relay coil, the second end of the relay coil is connected to the battery, and the load is connected to the battery through the normally open contact of the relay. When a high level needs to be output, the MCU controls the S end of the RS trigger to be high and the R end to be low; conversely, when a low level needs to be output, the MCU controls the S end of the RS trigger to be low and the R end to be high. When the MCU is reset, all I / O ports of the MCU are restored to the default state, for example, all are low level. At this time, the output of the RS trigger will maintain the previous state. For example, when the output of the RS trigger is high level, the MOS tube is turned on, and then the relay coil is obtained, the normally open contact of the relay is closed, and the battery supplies power to the load. If the system failure causes the MCU to reset or crash, so that the output of the MCU is all low level, the output of the RS trigger will maintain the current state without jumping, that is, high level state, so as to maintain the battery power supply to the load. However, when the system crashes, the driver cannot cut off the battery power supply to the load. In this embodiment, the state latch unit can be but not limited to an RS trigger. At the same time, on the basis of the existing LIMPHOME circuit, a signal control unit is added between the MCU and the state latch unit to control the input signal of the state latch unit when the MCU is reset or crashes to cut off the power supply circuit between the battery and the load. For example, when the system is in a normal state, the first input signal is at a high level and the second input signal is at a low level. At this time, the battery supplies power to the load. When the MCU is reset or crashes, at this time, the combination of the level state of the first input signal and the level state of the second input signal is a first level state combination, that is, when the level state of the first input signal is at a low level and the level state of the second input signal is at a low level, the RS trigger keeps the currently output control signal at a high level. If the driver needs to cut off the power supply circuit from the battery to the load, an interrupt signal can be given to the signal control unit to trigger the signal control unit to switch the level state combination of the first input signal and the second input signal to a second level state combination, for example, making the first input signal at a low level and the second input signal at a high level, so that the output of the RS trigger is a low level to cut off the power supply circuit from the battery to the load.

[0044] like Figure 3As shown, in this embodiment, the signal control unit includes: a logic gate subunit and an interrupt signal control subunit connected to the logic gate subunit; the interrupt signal control subunit responds to the interrupt signal to control the logic gate subunit to switch the combination of the level state of the first input signal and the level state of the second input signal to the second level state combination. The interrupt signal can be triggered by a physical switch or by a virtual control through a human-computer interaction interface.

[0045] Among them, the logic gate subunit includes: a first logic gate, a second logic gate and a third logic gate; the first input end of the first logic gate is connected to the output end of the interrupt signal control subunit, the second input end of the first logic gate is used to receive the first input signal, and the output end of the first logic gate is connected to the set end of the RS trigger; the input end of the second logic gate is connected to the output end of the interrupt signal control subunit and the first input end of the first logic gate, the output end of the second logic gate is connected to the first input end of the third logic gate, the second input end of the third logic gate is used to receive the second input signal, and the output end of the third logic gate is connected to the reset end of the RS trigger; the first logic gate is an AND gate, the second logic gate is a NOT gate, and the third logic gate is an OR gate.

[0046] The interrupt signal control subunit includes: a first switch and a voltage-dividing resistor; the first end of the first switch is grounded, the second end of the first switch is connected to the second end of the voltage-dividing resistor and connected to the first input end of the first logic gate and the input end of the second logic gate, and the first end of the voltage-dividing resistor is connected to the reference signal. The first switch is a reset switch, the reference signal is a high-level signal, and the reference signal can be provided by VDD.

[0047] In the normal working state of the system, the first switch is disconnected, the first input end of the first logic gate, that is, the AND gate, is at a high level under the action of VDD, the input end of the second logic gate, that is, the NOT gate, is at a high level under the action of VDD, and the first input end of the third logic gate, that is, the OR gate, is at a low level after the NOT gate. In this way, when the output end outs of the MCU is at a high level and the output end outr of the MCU is at a low level, the output end of the AND gate is at a high level, that is, the set end S of the RS trigger is at a high level, the output end of the OR gate is at a low level, that is, the reset end R of the RS trigger is at a low level, the output end out of the RS trigger is at a high level, the MOS tube is turned on, so that the normally open contact of the relay is closed, and the power supply circuit of the battery and the load is turned on. When the output end outs of the MCU is at a low level and the output end outr of the MCU is at a high level, the output end of the AND gate is at a low level, the output end of the OR gate is at a high level, the output end out of the RS trigger is at a low level, the MOS tube is turned off, so that the normally open contact of the relay is disconnected, and the power supply circuit of the battery and the load is disconnected. When the MCU crashes, the output terminal outs of the MCU outputs a low level, the output terminal outr of the MCU is a low level, the output terminal of the AND gate outputs a low level, the output terminal of the OR gate outputs a low level, and the output terminal out of the RS trigger outputs unchanged to maintain the previous output state. If the previous output state is a high level, the RS trigger keeps outputting a high level. At this time, the normally open contacts of the relay remain closed, and the battery supplies power to the load; if it is necessary to disconnect the power supply circuit between the battery and the load, the first switch can be pressed to close the first switch. At this time, the first input terminal of the AND gate is grounded, and its input becomes a low level. Similarly, the input terminal of the NOT gate becomes a low level, and its output becomes a high level. At this time, the output terminal of the AND gate is a low level, and the output terminal of the OR gate is a high level. Then the output terminal out of the RS trigger outputs a low level, the MOS tube is disconnected, and the relay coil loses power, the normally open contacts of the relay are disconnected, and the power supply circuit between the battery and the load is disconnected, thereby realizing the disconnection of the battery from supplying power to the load when the system crashes.

[0048] In a second aspect of the present invention, a control device is provided, comprising:

[0049] The LIMPHOME circuit described above; and

[0050] A controller is used to generate a first input signal and a second input signal.

[0051] In a third aspect of the present invention, a car is provided, comprising the above-mentioned control device.

[0052] In summary, this implementation uses the function of the external switch and logic gate combination circuit. When the MCU crashes, it can also be shut down through the external switch. It is easy to operate and saves power. It is safer and more convenient than using the RS trigger alone to control the output, thereby effectively improving the reliability and safety of the vehicle body safety circuit.

[0053] The optional embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above embodiments. Within the technical concept of the embodiments of the present invention, a variety of simple modifications can be made to the technical solutions of the embodiments of the present invention, and these simple modifications all belong to the protection scope of the embodiments of the present invention.

[0054] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the embodiments of the present invention will not further describe various possible combinations.

[0055] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the embodiments of the present invention, they should also be regarded as the contents disclosed in the embodiments of the present invention.

Claims

1. A LIMPHOME circuit, characterized in that: The circuit comprises: a state latch unit, configured to output a control signal of a corresponding level state according to a level state of a first input signal and a level state of a second input signal, and to maintain a level state of a currently output control signal when a combination of a level state of the first input signal and a level state of the second input signal is a first level state combination; A signal control unit connected to the state latch unit, for switching the combination of the level state of the first input signal and the level state of the second input signal to a second level state combination and inputting the combination into the state latch unit in response to an interrupt signal; The level state is a low level or a high level, and the state latch unit is an RS trigger; The signal control unit comprises: A logic gate subunit and an interrupt signal control subunit connected to the logic gate subunit; The interrupt signal control subunit controls the logic gate subunit to switch the combination of the level state of the first input signal and the level state of the second input signal to the second level state combination in response to the interrupt signal.

2. The LIMPHOME circuit according to claim 1, characterized in that: The logic gate subunit comprises: A first logic gate, a second logic gate and a third logic gate; The first input end of the first logic gate is connected to the output end of the interrupt signal control subunit, the second input end of the first logic gate is used to receive the first input signal, and the output end of the first logic gate is connected to the set end of the RS trigger; The input end of the second logic gate is connected to the output end of the interrupt signal control subunit and the first input end of the first logic gate, the output end of the second logic gate is connected to the first input end of the third logic gate, the second input end of the third logic gate is used to receive the second input signal, and the output end of the third logic gate is connected to the reset end of the RS trigger; The first logic gate is an AND gate, the second logic gate is a NOT gate, and the third logic gate is an OR gate.

3. The LIMPHOME circuit according to claim 2, characterized in that: The interrupt signal control subunit comprises: A first switch and a voltage dividing resistor; The first end of the first switch is grounded, the second end of the first switch is connected to the second end of the voltage divider resistor and connected to the first input end of the first logic gate and the input end of the second logic gate, and the first end of the voltage divider resistor is connected to a reference signal.

4. The LIMPHOME circuit according to claim 3, characterized in that: The first switch is a reset switch.

5. The LIMPHOME circuit according to claim 3, characterized in that: The reference signal is a high level signal.

6. The LIMPHOME circuit according to claim 3, characterized in that: The first level state combination is: the level state of the first input signal is a low level, and the level state of the second input signal is a low level; The second level state combination is: the level state of the first input signal is a low level, and the level state of the second input signal is a high level.

7. A control device, characterized in that: include: The LIMPHOME circuit as claimed in any one of claims 1 to 6; as well as A controller is provided for generating the first input signal and the second input signal.

8. A car, characterized in that: Comprising the control device as claimed in claim 7.

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