Safety protection device, vehicle-mounted mainboard and safety protection method

Abstract

The invention provides a safety protection device, a vehicle-mounted mainboard and a safety protection method, and the safety protection device comprises a switch which is arranged on a negative loop of a circuit between a mainboard power input positive terminal and a mainboard power input negative terminal; the first sampling circuit is used for sampling a negative electrode output current at a mainboard power supply input negative electrode terminal and sending the negative electrode output current to the electric leakage detection circuit; the electric leakage detection circuit is used for sending an electric leakage abnormal signal to the self-locking circuit when the negative electrode output current is greater than an electric leakage abnormal threshold value; the self-locking circuit is used for sending a turn-off control signal to the switch control circuit when receiving the electric leakage abnormal signal; and the switch control circuit is used for controlling the switch to be turned off when receiving the turn-off control signal. According to the scheme, the power supply loop of the vehicle-mounted mainboard can be turned off in time, so that the safety of the vehicle is improved.

Description

Technical Field

[0001] The present application relates to the field of vehicle safety technology, and in particular to a safety protection device, a vehicle-mounted mainboard, and a safety protection method. Background Art

[0002] At present, in agricultural vehicles, engineering vehicles, buses, family cars and other vehicles, the body is usually used as a common ground plate to provide a return path for electrical equipment. In addition, some vehicle-mounted equipment requires an external antenna, and the external antenna is directly connected to the vehicle motherboard.

[0003] As the vehicle ages, the ground of the external antenna will form a grounding point with the vehicle body due to corrosion, looseness, improper installation, etc. Since the antenna is directly connected to the vehicle mainboard, a minimum impedance return path will be formed through the grounding point to flow through the vehicle mainboard. Since the vehicle mainboard has limited overcurrent capacity, the current flowing through the minimum impedance return path will damage the vehicle mainboard, and the vehicle safety is poor. Summary of the invention

[0004] The purpose of the embodiments of the present application is to provide a safety protection device, a vehicle-mounted mainboard and a safety protection method to improve vehicle safety.

[0005] In a first aspect, an embodiment of the present application provides a safety protection device, the device comprising: a switch, a first sampling circuit, a leakage detection circuit, a self-locking circuit and a switch control circuit, wherein:

[0006] The switch is arranged on the negative loop of the circuit between the positive terminal of the mainboard power input and the negative terminal of the mainboard power input;

[0007] The first sampling circuit is used to sample the negative output current at the negative terminal of the mainboard power input, and send the negative output current to the leakage detection circuit;

[0008] The leakage detection circuit is used to send a leakage abnormality signal to the self-locking circuit when the negative electrode output current is greater than the leakage abnormality threshold;

[0009] The self-locking circuit is used to send a shutdown control signal to the switch control circuit when receiving the leakage abnormality signal;

[0010] The switch control circuit is used to control the switch to turn off when receiving the shutdown control signal.

[0011] In the process of implementing the above scheme, a leakage detection circuit is used to detect whether the negative pole output current is greater than the leakage abnormality threshold, and when the negative pole output current is greater than the leakage abnormality threshold, the negative pole circuit is disconnected by the self-locking circuit control switch. On the one hand, the power supply circuit of the vehicle mainboard can be shut down in time, thereby improving the safety of the vehicle; on the other hand, compared with the safety protection method of using a fuse in the related technology, the above scheme uses a self-locking circuit to disconnect the leakage protection method of the negative pole circuit, which is faster and is conducive to further improving the safety of the vehicle.

[0012] In an implementation of the first aspect, the device further includes: a processing module, the first sampling circuit and the self-locking circuit are electrically connected to the processing module respectively, wherein:

[0013] The first sampling circuit is further used to send the negative output current to the processing module;

[0014] The processing module is used to determine whether a leakage abnormality occurs in the mainboard based on the negative electrode output current, and send the leakage abnormality signal to the self-locking circuit when a leakage abnormality occurs in the mainboard.

[0015] In the process of implementing the above scheme, leakage anomaly detection can be performed through the processing module and the leakage detection circuit respectively, which is conducive to improving the accuracy of leakage anomaly detection and further improving the working efficiency of the vehicle mainboard.

[0016] In an implementation of the first aspect, the device further includes: a second sampling circuit electrically connected to the processing module;

[0017] The second sampling circuit is used to sample the positive input current at the positive terminal of the mainboard power input, and send the positive input current to the processing module;

[0018] The processing module is further used to determine whether an abnormality occurs in the mainboard based on the positive input current and the negative output current, and send an abnormality signal of the mainboard to the self-locking circuit when an abnormality occurs in the mainboard;

[0019] The self-locking circuit is also used to send the shutdown control signal to the switch control circuit after receiving the mainboard abnormality signal.

[0020] During the implementation of the above scheme, the positive input current is collected through the second sampling circuit, so that the processing module can jointly determine whether the vehicle mainboard has leakage, short circuit, overload and other abnormalities based on the positive input current and the negative output current, and shut down the negative circuit when an abnormality occurs. On the one hand, it is beneficial to improve the safety of the above safety protection device; on the other hand, it enables the above safety protection device to be applied to more application scenarios, which is beneficial to improving the applicability of the above safety protection device 100.

[0021] In an implementation of the first aspect, the device further includes: a recovery circuit electrically connected to the switch control circuit;

[0022] The recovery circuit is used to send a switch-on control signal to the switch control circuit when receiving the recovery signal;

[0023] The switch control circuit is further used to control the switch to be turned on when receiving the turn-on control signal.

[0024] During the implementation of the above scheme, when the leakage anomaly is eliminated, the recovery circuit can automatically reconnect the negative circuit. On the one hand, it allows the vehicle main board to resume normal operation, which is beneficial to improving the reliability and practicality of the safety protection device. On the other hand, by setting up a recovery circuit, the safety protection device can be quickly restored when the leakage anomaly is eliminated, reducing the downtime caused by the fault, which is beneficial to improving the operating efficiency of the vehicle main board.

[0025] In an implementation of the first aspect, the device further includes: a restoration signal generating module electrically connected to the leakage detection circuit;

[0026] The leakage detection circuit is further configured to send a non-leakage signal to the recovery signal generation module when the negative electrode output current is not greater than the leakage abnormality threshold;

[0027] The recovery signal generating module is used to generate a recovery signal based on the non-leakage signal, and send the recovery signal to the recovery circuit.

[0028] In the implementation process of the above scheme, a recovery signal is directly generated by the non-leakage signal output by the leakage detection circuit to realize the recovery of the self-locking state. On the one hand, the self-locking state can be restored without manual access, which is beneficial to improving the recovery efficiency of the above-mentioned safety protection device; on the other hand, the self-locking state can be quickly restored through the non-leakage signal, which is beneficial to improving the reliability and stability of the above-mentioned safety protection device.

[0029] In an implementation of the first aspect, the processing module is further configured to:

[0030] After receiving the leakage abnormality signal and delaying for a preset time, the recovery signal is generated, and the recovery signal is sent to the recovery circuit; wherein the leakage abnormality signal is sent by the leakage detection circuit to the processing module;

[0031] And / or, generating the recovery signal after receiving the recovery instruction, and sending the recovery signal to the recovery circuit.

[0032] In the process of implementing the above solution, the processing module generates a recovery signal regularly or based on a user instruction to try to recover the self-locking state, which is beneficial to improving the recovery efficiency of the above safety protection device.

[0033] In an implementation of the first aspect, the device further includes: an alarm module electrically connected to the processing module and / or the leakage detection circuit;

[0034] The alarm module is used to issue an alarm when receiving the mainboard abnormality signal sent by the processing module; and / or, to issue an alarm when receiving the leakage abnormality signal sent by the leakage detection circuit.

[0035] In the process of implementing the above scheme, by setting up an alarm module, on the one hand, timely alarm of abnormal situations can be realized, which is conducive to improving the safety of the above safety protection device; on the other hand, the user can locate the fault point more quickly through the alarm module, thereby shortening the troubleshooting time and improving maintenance efficiency.

[0036] In a second aspect, an embodiment of the present application provides a vehicle-mounted mainboard, comprising: a mainboard body provided with a mainboard power input positive terminal and a mainboard power input negative terminal, and a safety protection device connected to the mainboard body; wherein the safety protection device is a safety protection device provided by the first aspect or any possible implementation method of the first aspect.

[0037] In a third aspect, an embodiment of the present application provides a safety protection method, which is applied to a processing module in a safety protection device provided in the first aspect or any possible implementation method of the first aspect, and the method includes: obtaining a negative output current collected by a first sampling circuit; based on the negative output current, determining whether an abnormality occurs in a mainboard; and when an abnormality occurs in the mainboard, sending a mainboard abnormality signal to the self-locking circuit.

[0038] In an implementation of the third aspect, the method further includes: obtaining a positive input current collected by a second sampling circuit; and judging whether an abnormality occurs in the mainboard based on the negative output current, including: judging whether an abnormality occurs in the mainboard based on the negative output current and the positive input current.

[0039] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or be understood by practicing the embodiments of the present application. The purpose and other advantages of the present application can be realized and obtained by the structures specifically pointed out in the written description, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0041] Figure 1 A schematic diagram of a normal return path of a vehicle mainboard and other power devices in a vehicle in the related art;

[0042] Figure 2 A schematic diagram of the minimum impedance return path formed by the iron point in the related art;

[0043] Figure 3 A schematic diagram of the structure of a safety protection device provided in an embodiment of the present application;

[0044] Figure 4 A circuit diagram of a first sampling circuit provided in an embodiment of the present application;

[0045] Figure 5 A circuit diagram of a leakage protection circuit provided in an embodiment of the present application;

[0046] Figure 6 A circuit diagram of an operational amplifier follower provided in an embodiment of the present application;

[0047] Figure 7 A circuit diagram of a self-locking circuit provided in an embodiment of the present application;

[0048] Figure 8 A circuit diagram of a switch and a switch control circuit provided in an embodiment of the present application;

[0049] Fig. 9 A circuit diagram of a recovery circuit provided in an embodiment of the present application;

[0050] Fig.10 A circuit diagram of a second sampling circuit provided in an embodiment of the present application;

[0051] Fig.11 The relationship between the integral value output by the integration circuit provided in the embodiment of the present application and the magnitude of the current flowing in the circuit;

[0052] Fig.12 A flowchart of the security protection method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0053] The following will describe the technical solutions in the embodiments of the present application in conjunction with the accompanying drawings in the embodiments of the present application. The following embodiments are only used to more clearly illustrate the technical solutions of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0054] In the vehicle's electrical system, the vehicle body usually acts as a common ground plane to provide a return path for electrical devices. The body resistance is normally small, usually in the milliohm range. Figure 1 As shown, where:

[0055] (1) The return path of other power devices is: it flows out from the vehicle battery, flows through other power devices, and returns to the negative electrode of the vehicle battery through the vehicle body;

[0056] (2) The return path of the vehicle mainboard is: it flows out from the vehicle battery, flows through the vehicle mainboard, and then returns to the negative electrode of the vehicle battery. The vehicle mainboard and the housing are connected in a floating manner, and a fuse is set at the negative electrode.

[0057] As the vehicle ages, the ground of the external antenna may form a ground point with the vehicle body due to corrosion, looseness, improper installation, etc. Figure 2 As shown in the figure, since the antenna is directly connected to the vehicle mainboard, a minimum impedance return path will be formed through the grounding point to flow through the vehicle mainboard. Since the vehicle mainboard has limited overcurrent capacity, the current flowing through the minimum impedance return path will damage the vehicle mainboard, resulting in poor vehicle safety.

[0058] Based on this, an embodiment of the present application provides a safety protection device, which detects whether the negative pole output current is greater than the leakage abnormality threshold through a leakage detection circuit, and disconnects the negative pole circuit through a self-locking circuit control switch when the negative pole output current is greater than the leakage abnormality threshold. On the one hand, it can achieve timely shutdown of the vehicle mainboard power supply circuit, thereby improving vehicle safety; on the other hand, compared with the safety protection method of using a fuse in the related technology, the above scheme uses a self-locking circuit to disconnect the leakage protection method of the negative pole circuit, which is faster and beneficial to further improve the safety of the vehicle.

[0059] The following is a detailed description of the above safety protection devices. Figure 3 , the embodiment of the present application provides a safety protection device 100, the device comprising:

[0060] The switch 110 is arranged on the negative loop of the circuit between the positive terminal of the mainboard power input and the negative terminal of the mainboard power input;

[0061] The first sampling circuit 120 is used to sample the negative output current at the negative terminal of the mainboard power input, and send the negative output current to the leakage detection circuit 130;

[0062] The leakage detection circuit 130 is used to send a leakage abnormality signal to the self-locking circuit when the negative electrode output current is greater than the leakage abnormality threshold;

[0063] The self-locking circuit 140 is used to send a shutdown control signal to the switch control circuit when receiving a leakage abnormality signal;

[0064] The switch control circuit 150 is used to control the switch to turn off when receiving a turn-off control signal.

[0065] Understandably, Figure 3 The board circuit shown in is the original circuit in the mainboard. The mainboard power input positive terminal and the mainboard power input negative terminal are two terminals on the mainboard connected to the power supply. The mainboard power input positive terminal and the mainboard power input negative terminal are respectively connected to the positive and negative poles of the power supply. The power supply current is input from the mainboard power input positive terminal, flows through the board circuit and the switch 110 and the first sampling circuit 120 in the above-mentioned safety protection device 100, and then returns to the mainboard power input negative terminal, thereby forming a complete return path.

[0066] In addition, it is understandable that after the grounding point is formed, the large current generated by other load devices will flow into the return path of the vehicle mainboard through the grounding point, that is, leakage occurs. When leakage occurs, the negative output current at the negative terminal of the mainboard power input of the vehicle mainboard will increase. Therefore, by monitoring the size of the negative output current, it is possible to monitor whether a leakage fault occurs.

[0067] An optional implementation of the first sampling circuit 120 is introduced below:

[0068] For example, the first sampling circuit 120 may use a Hall sampling circuit for sampling, such as Figure 4As shown, the first sampling circuit 120 uses a Hall current sampling chip U1 to perform current sampling, and the Hall current sampling chip is, for example, the MT9222 Hall current sampling chip. The MT9222 chip is composed of a precise, low-offset linear Hall circuit and a built-in low-insertion resistance current conductor path. The external current flowing through this current conductor path will generate a magnetic field, and the Hall current sampling chip will convert it into a voltage signal output proportional to the input current. Take a certain scenario as an example: the Hall current sampling chip can select a full-scale detection range of ±20A, a sensitivity of 100mV / A, a normal working current of 1A, a conversion voltage of 100mV, a maximum allowable leakage current of 7A, and a conversion voltage of 700mV. Figure 4 The GROUND_C_ADC shown in is the negative output current.

[0069] In addition, it is understandable that the above Figure 4 The V5V_SYS in the motherboard refers to the 5V power supply interface, which can be used to Figure 4 It powers the Hall current sampling chip and the comparator and other devices that will be introduced in the subsequent content.

[0070] An optional implementation of the leakage detection circuit 130 is introduced below:

[0071] For example, the leakage detection circuit 130 may use a sampling comparator to compare the negative output current with the leakage abnormality threshold, see Figure 5 The leakage detection circuit 130 uses a comparator U6 to compare the negative output current GROUND_C_ADC with the leakage abnormality threshold. The comparator U6 can be a comparator of model RS8904XF.

[0072] In addition, it can be understood that when comparing the negative output current and the leakage abnormality threshold, the negative output current and the leakage abnormality threshold can be compared directly, or the two can be converted into voltage and then compared. For example, the maximum leakage current that the vehicle mainboard can withstand is 7A, and the sensitivity of the above-mentioned Hall current sampling chip is 100mV / A. Then the maximum leakage current is converted into a conversion voltage of 7A*100mV / A=700mV, and the 2.5V built-in voltage of the Hall current sampling chip is added to obtain a leakage abnormality threshold of 2.5V+0.7V=3.2V. Figure 5 The positive input terminal VIN+ of the middle comparator U6 is connected to the negative output current GROUND_C_ADC, which is adjusted to a voltage value through the resistor R36, and the negative input terminal VIN- is connected to a reference voltage, and the reference voltage value can be adjusted by the resistance values ​​of the resistors R44 and R47.

[0073] In addition, it is understandable that the sensitivity of the above-mentioned safety protection device 100 can be adjusted by the leakage abnormality threshold. If the leakage abnormality threshold is adjusted to a value less than the maximum leakage voltage that the vehicle mainboard can withstand, the sensitivity of the safety protection device will be higher. On the contrary, if the leakage abnormality threshold is adjusted to a value greater than the maximum leakage voltage that the vehicle mainboard can withstand, the sensitivity of the safety protection device will be reduced. By adjusting the sensitivity of the safety protection device 100, the safety protection device 100 can be applied to more application scenarios.

[0074] After the comparator U6 compares the negative output current with the leakage abnormality threshold, if the negative output current is greater than the leakage abnormality threshold, the output signal FAULT_S of its output terminal VOUT is adjusted to a high level signal, and the high level FAULT_S signal is sent to the self-locking circuit 140.

[0075] In addition, it is understandable that an op amp follower can also be used to isolate the output of the Hall current sampling chip from the subsequent circuit. An optional implementation of the op amp follower is introduced below:

[0076] For example, see Figure 6 The leakage detection circuit 130 can use an operational amplifier follower U3 to isolate the output of the Hall current sampling chip from the subsequent circuit. The operational amplifier can use an operational amplifier of model RS8412XK. The positive input terminal +INA of the operational amplifier is connected to the negative output current GROUND_C_ADC, and the output terminal OUTA is connected to the negative input terminal -INA. The follower signal IN1 is sent from the output terminal OUTA to the leakage detection circuit.

[0077] An optional implementation of the self-locking circuit 140 is introduced below:

[0078] For example, the self-locking circuit 140 can generate a shutdown control signal when a leakage abnormality occurs by cooperating with a PMOS tube and an NMOS tube. Figure 7 The self-locking circuit 140 mainly includes a PMOS transistor Q2 and an NMOS transistor Q3, wherein the S pole of the PMOS transistor Q2 is connected to the power supply V5V_SYS, the D pole is grounded, and the G pole is connected to the output terminal of the switch enable signal N4V5_EN. The G pole of the NMOS transistor Q3 inputs the leakage abnormality signal FAULT_S, the S pole is grounded, and the D pole is connected to the output terminal of the switch enable signal N4V5_EN.

[0079] The working principle of the self-locking circuit 140 is introduced below:

[0080] Normal state: When the FAULT_S signal is low, it means that the negative output current is not greater than the leakage abnormality threshold. At this time, the gate (G pole) of Q3 is low, the gate voltage is not higher than the source (S pole), and Q3 is in the off state; the gate (G pole) of Q2 is high, the gate (G pole) voltage is higher than the source (S pole) voltage, and Q2 is also in the off state. At this time, the switch enable signal N4V5_EN is connected to the power supply V5V_SYS, and the switch enable signal N4V5_EN is high (the high level switch enable signal N4V5_EN is a non-leakage signal).

[0081] Leakage self-locking state: When the FAULT_S signal changes from low level to high level, it means that the negative output current is greater than the leakage abnormality threshold. At this time, the gate (G pole) of Q3 is high level, the gate (G pole) voltage is higher than the source (S pole) voltage, and Q3 is turned on; the gate (G pole) of Q2 becomes low level, the gate (G pole) voltage is lower than the source (S pole) voltage, and Q2 is turned on. At this time, since Q3 is turned on, the switch enable signal N4V5_EN becomes low level (the low level switch enable signal N4V5_EN is the leakage abnormality signal);

[0082] In addition, after Q2 is turned on, the circuit where the power supply V5V_SYS and the resistor R10 are located is turned on, and the gate (G pole) of Q3 is connected to the conduction circuit where the power supply V5V_SYS and the resistor R10 are located through the resistor R9. Therefore, the gate (G pole) of Q3 will continue to be in a high level state, and the switch enable signal N4V5_EN will also continue to be in a low level state, thereby achieving self-locking of the switch off state.

[0083] It is understandable that the safety protection device after self-locking can be restored by shutting down Q2. There are also many ways to shut down Q2. The subsequent content will introduce in detail an optional implementation method for shutting down Q2.

[0084] An optional implementation of the switch control circuit 150 and the switch 110 is introduced below:

[0085] For example, the switch 110 can be implemented by using two PMOS transistors, and the switch control circuit 150 can be implemented by using an NMOS transistor and a PMOS transistor. Figure 8The switch 110 can be implemented by two PMOS tubes Q5 and Q6 with a back-to-back design. The two PMOS tubes can be PMOS tubes with a model of LP7411DT1WG. The drain-source voltage of the PMOS tube is -60V, and the maximum current is -20A. It can be applied to application scenarios with a maximum leakage current of 7A; the switch control circuit 150 can be implemented by a PMOS tube Q8 and an NMOS tube Q7. The PMOS tube can be a PMOS tube with a model of LP3407LT1G, and the NMOS tube can be an NMOS tube with a model of L2N7002LT1G.

[0086] The working principle of the switch 110 and the switch control circuit 150 is introduced below:

[0087] Normal state: In the normal state, the switch enable signal N4V5_EN is in a high level state, Q5, Q6, Q7 and Q8 are all in the on state, and the negative circuit is connected.

[0088] Off state: After the switch enable signal N4V5_EN changes from high level to low level, Q5, Q6, Q7 and Q8 are all in the off state, and the negative circuit is turned off.

[0089] In addition, it is understandable that the switch 110 uses two PMOS tubes in a back-to-back design to prevent the situation where the diode cannot be completely turned off due to the freewheeling current.

[0090] As an optional implementation of the above-mentioned safety protection device, the above-mentioned safety protection device 100 further includes:

[0091] The processing module, the first sampling circuit 120 and the self-locking circuit 140 are electrically connected to the processing module respectively, wherein:

[0092] The first sampling circuit 120 is also used to send the negative output current to the processing module.

[0093] The processing module is used to determine whether the mainboard has leakage based on the negative output current, and send a leakage abnormality signal to the self-locking circuit 140 when the mainboard has leakage abnormality.

[0094] It is understandable that the above solution uses a processing module to detect leakage anomalies, and the leakage anomaly detection scheme of the processing module can be used in combination with the above solution of using the leakage detection circuit 130 to perform leakage detection, for example:

[0095] (1) The processing module and the leakage detection circuit 130 are used to perform leakage abnormality detection respectively, and a shutdown control signal is sent to the self-locking circuit 140 only when both detect leakage abnormality;

[0096] (2) The processing module and the leakage detection circuit 130 are used to perform leakage abnormality detection respectively. When one of them detects leakage abnormality, a shutdown control signal is sent to the self-locking circuit 140.

[0097] The above solution can perform leakage anomaly detection through the processing module and the leakage detection circuit 130 respectively, which is beneficial to improve the accuracy of leakage anomaly detection and further improve the working efficiency of the vehicle mainboard.

[0098] An optional implementation method for restoring the self-locking circuit 140 after self-locking is introduced below:

[0099] As an optional implementation of the above safety protection device, the above safety protection device 100 further includes: a recovery circuit electrically connected to the switch control circuit 150;

[0100] A recovery circuit, configured to send a switch-on control signal to the switch control circuit 150 upon receiving a recovery signal;

[0101] The switch control circuit 150 is further configured to control the switch 110 to be turned on when receiving a turn-on control signal.

[0102] For example, the above recovery circuit can also be implemented by using a PMOS tube and an NMOS tube, see Fig. 9 The PMOS tube can be a PMOS tube of model LP3407LT1G, and the NMOS tube can be an NMOS tube of model L2N7002LT1G. The drain (D pole) of the PMOS tube Q1 is connected to the output end of the switch enable signal N4V5_EN, the source (S pole) is connected to the V5V_SYS power supply, and the gate (G pole) is connected to the drain (D pole) of the NMOS tube Q4; the source (S pole) of the NMOS tube Q4 is grounded, and the gate (G pole) is connected to the input end of the recovery signal COC.

[0103] The working principle of the recovery circuit is introduced below:

[0104] Normal state: The recovery signal COC is low, FAULT_S is low or high impedance, MOS tubes Q1 to Q4 are all in the cut-off state, N4V5_EN is high, the subsequent switch is enabled to open the negative circuit, and the system works normally.

[0105] Protection state: When the signal FAULT_S becomes a high level state, the MOS tube Q3 is turned on, the gate level of the MOS tube Q2 is pulled low, and the MOS tube Q2 is turned on, so that the gate of the MOS tube Q3 becomes a high level, and the N4V5_EN is locked in a low state and is no longer affected by the signal FAULT_S, thus forming a self-locking state.

[0106] Recovery state: When the signal FAULT_S returns to a low level, the COC output is controlled to be high, so that the MOS tube Q4 is turned on, and the gate level of Q1 is pulled down. At this time, Q1 is turned on, and the V5V_SYS high-level signal pulls up the gate level of Q2 through Q1, so that Q2 is turned off. At this time, the gate of Q3 becomes a low level, and Q3 is turned off. Therefore, N4V5_EN becomes a high level again to enable the subsequent switch circuit.

[0107] In the above scheme, when the leakage anomaly is eliminated, the recovery circuit can automatically reconnect the negative pole circuit. On the one hand, it enables the vehicle mainboard to resume normal operation, which is beneficial to improving the reliability and practicality of the safety protection device. On the other hand, by setting up the recovery circuit, the safety protection device can be quickly restored when the leakage anomaly is eliminated, reducing the downtime caused by the fault, which is beneficial to improving the operating efficiency of the vehicle mainboard.

[0108] The following are two implementation methods of the above recovery signal:

[0109] The first implementation method: using the FAULT_S signal output by the leakage detection circuit 130 to perform recovery, the specific scheme is as follows:

[0110] As an optional implementation of the above safety protection device, the above safety protection device 100 further includes: a recovery signal generating module electrically connected to the leakage detection circuit 130;

[0111] The leakage detection circuit 130 is further used to send a non-leakage signal to the recovery signal generation module when the negative electrode output current is not greater than the leakage abnormality threshold;

[0112] The recovery signal generating module is used to generate a recovery signal based on the non-leakage signal and send the recovery signal to the recovery circuit.

[0113] In this implementation, for example, a MOS tube is used to reverse the polarity of the FAULT_S signal output by the leakage detection circuit 130 , thereby realizing recovery from the self-locking state.

[0114] It is understandable that, in addition to using a MOS tube to output the FAULT_S signal with reverse polarity, a processing module, an inverter, etc. may also be used to output the FAULT_S signal with reverse polarity.

[0115] The above scheme directly generates a recovery signal through the non-leakage signal output by the leakage detection circuit to realize the recovery of the self-locking state. On the one hand, the self-locking state can be restored without manual access, which is beneficial to improving the recovery efficiency of the above-mentioned safety protection device 100; on the other hand, the self-locking state can be quickly restored through the non-leakage signal, which is beneficial to improving the reliability and stability of the above-mentioned safety protection device 100.

[0116] The second implementation method: restore the self-locking state through the processing module. The specific solution is as follows:

[0117] As an optional implementation of the above safety protection device, the processing module is further used for:

[0118] After receiving the leakage abnormality signal and delaying for a preset time, a recovery signal is generated, and the recovery signal is sent to the recovery circuit; wherein the leakage abnormality signal is sent to the processing module by the leakage detection circuit;

[0119] And / or, generating a recovery signal after receiving the recovery instruction, and sending the recovery signal to the recovery circuit.

[0120] Exemplarily, the above-mentioned recovery instruction may be a recovery instruction issued by a user, and the processing module may generate a recovery signal based on the recovery instruction issued by the user to thereby recover the self-locking state.

[0121] It is understandable that after a leakage anomaly occurs and the negative pole circuit is disconnected, the processing module can periodically generate a recovery signal to try to restore the self-locking state. If the anomaly has not been repaired, the leakage detection circuit 130 will still re-send the leakage anomaly signal to the self-locking circuit 140, so that the self-locking circuit 140 re-enters the self-locking state.

[0122] The above solution generates a recovery signal by the processing module at a fixed time or based on a user instruction to attempt to recover the self-locking state, which is beneficial to improving the recovery efficiency of the above safety protection device 100.

[0123] In addition to detecting leakage of the vehicle mainboard, the above safety protection device 100 can also detect other faults such as short circuit and overload. The specific scheme is as follows:

[0124] As an optional implementation of the above safety protection device, the above safety protection device 100 further includes: a second sampling circuit electrically connected to the processing module;

[0125] A second sampling circuit is used to sample the positive input current at the positive terminal of the mainboard power input and send the positive input current to the processing module;

[0126] The processing module is further used to determine whether the mainboard is abnormal based on the positive input current and the negative output current, and send a mainboard abnormality signal to the self-locking circuit 140 when the mainboard is abnormal;

[0127] The self-locking circuit 140 is also used to send a shutdown control signal to the switch control circuit 150 after receiving an abnormal signal from the mainboard.

[0128] For example, the second sampling circuit can sample the positive input current based on a sampling resistor and a high-side current sampling chip, see Fig.10 , the sampling resistor can use four sampling resistors connected in series and parallel, for example Fig.10 The resistors R2, R3, R4 and R6 shown in the figure can flexibly configure the resistance size of the four sampling circuits according to the positive input current requirements. For example, in a certain scenario, the maximum positive input current is 3A, so four 0.05Ω sampling resistors with a package of 2512 can be selected, and the maximum power of each channel is 0.225W by series-parallel connection. The overall resistance of the sampling resistor is 0.05Ω, so the maximum sampling voltage is 0.15V, the normal working current is 1A, and the normal sampling voltage is 50mV. The high-side current sampling chip can use the high-side current sampling chip model TPA191A1, with an input voltage of up to 36V and a selectable fixed gain. For example, in a certain scenario, the voltage range of the positive input current after passing through the sampling resistor is 50mV~150mV, so a chip with a fixed gain of 20V / V can be selected, and the voltage range of P_CUR_ADC after amplification is 1V~3V, which can be directly processed later.

[0129] It is understandable that the processing module can be used to quantize and digitally process the amplified P_CUR_ADC, or Fig.10 The integration circuit shown in the figure is used for filtering. The integration circuit can be composed of an operational amplifier of model RS8412XK. The calculation formula of the integration circuit is:

[0130]

[0131] Among them, RC is the integration constant, and the integration time can be configured by configuring the size of the integration capacitor of the external integration resistor; V ref It can be configured to allow the maximum current through the sampling resistor (that is, Fig.10 VREFG in the IN It is the voltage value converted by the current P_CUR_ADC during actual operation. From the above formula, we can know that the integral value output by the integration circuit is inversely proportional to the current flowing through the circuit. The relationship is as follows: Fig.11 As shown, Fig.11 The horizontal axis in the figure represents the integration time t, and the curve between the part labeled 1 and the part labeled 2 represents the voltage function (V ref -V IN ) changes with time, and the integral value is the area of ​​the part marked with number 1. refThe square area formed within the sampling time T (that is, the sum of the area of ​​the part marked 1 and the area of ​​the part marked 2) is the integral value within the time T after the maximum current allowed in the circuit is converted into voltage. Then, the effective value of the voltage converted by the actual current in the circuit can be obtained by dividing the area of ​​the part marked 2 by the sampling time T, and then the positive input current P_CUR_ADC can be obtained, thereby reducing the influence of interference and noise; in addition, the sampling times of the ADC can be reduced by setting the integration time, thereby reducing the consumption of CPU resources.

[0132] In addition, it is understandable that Fig.10 Another output signal G_CUR_CLR in is used to discharge the integration capacitor. After the capacitor is fully charged, the integration circuit will fail, so the integration capacitor needs to be discharged before the next round of sampling.

[0133] It can be understood that after obtaining the positive input current, the processing module can determine whether the vehicle mainboard has leakage, short circuit, overload and other faults based on the positive input current and the negative input current. When any fault occurs, a mainboard abnormality signal is sent to the self-locking circuit 140, thereby shutting down the negative circuit.

[0134] The above scheme collects the positive input current through the second sampling circuit, so that the processing module can jointly judge whether the vehicle mainboard has leakage, short circuit, overload and other abnormalities based on the positive input current and the negative output current, and shut down the negative circuit when an abnormality occurs. On the one hand, it is beneficial to improve the safety of the above safety protection device 100; on the other hand, it enables the above safety protection device 100 to be applied to more application scenarios, which is beneficial to improving the applicability of the above safety protection device 100.

[0135] Exemplarily, the above safety protection device 100 may also have an alarm function, and the specific solution is as follows:

[0136] As an optional implementation of the above safety protection device, the above safety protection device 100 further includes: an alarm module electrically connected to the processing module and / or the leakage detection circuit;

[0137] The alarm module is used to generate an alarm when receiving a mainboard abnormality signal sent by the processing module; and / or, to generate an alarm when receiving a leakage abnormality signal sent by the leakage detection circuit 130.

[0138] It can be understood that the alarm module can be an audio-visual alarm module installed on the vehicle main board; it can also be an LED display module that can display abnormal information; it can also be a communication module that can send abnormal information to the user end through the communication interface of the vehicle board, thereby realizing abnormal alarm.

[0139] By setting up an alarm module, the above scheme can, on the one hand, realize timely alarm of abnormal situations, which is beneficial to improving the safety of the above safety protection device 100; on the other hand, the user can locate the fault point more quickly through the alarm module, thereby shortening the troubleshooting time and improving maintenance efficiency.

[0140] It can be understood that the above-mentioned leakage detection circuit 130 can determine whether it is necessary to output warning information and CAN messages by detecting the difference between the positive input current and the negative output current. When the negative output current exceeds the leakage abnormality threshold, a leakage abnormality signal is sent to the self-locking circuit.

[0141] Based on the same inventive concept, an embodiment of the present application also provides a vehicle-mounted mainboard, comprising: a mainboard body provided with a mainboard power input positive terminal and a mainboard power input negative terminal, and a safety protection device connected to the mainboard body; wherein the safety protection device is any one of the above-mentioned safety protection devices 100.

[0142] See also Fig.12 Based on the same inventive concept, the embodiment of the present application further provides a security protection method, which is applied to the processing module of the above-mentioned security protection device 100, and the method includes:

[0143] Step S210: obtaining the negative electrode output current collected by the first sampling circuit 120;

[0144] Step S220: judging whether an abnormality occurs in the mainboard based on the negative output current;

[0145] Step S230: When an abnormality occurs to the mainboard, a mainboard abnormality signal is sent to the self-locking circuit 140 .

[0146] As an optional implementation of the above safety protection method, the above safety protection method further includes: acquiring the positive input current collected by the second sampling circuit;

[0147] At this time, the above step S230 includes: judging whether an abnormality occurs in the mainboard based on the negative output current and the positive input current.

[0148] It should be pointed out that the processing module in the above-mentioned safety protection device 100, in addition to the two functions of judging whether the vehicle main board has leakage abnormalities based on the negative output current and judging whether the vehicle main board has leakage, short circuit, overload and other abnormalities based on the positive input current and negative output current, can also have functions such as self-locking state recovery and abnormal alarm. The safety protection method for realizing other functions can refer to the introduction of the processing module in the above description of the safety protection device 100, and will not be repeated in the embodiments of the present application.

[0149] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0150] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0151] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0152] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0153] The above description is only an embodiment of the present application and is not intended to limit the scope of protection of the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the scope of protection of the present application.

Claims

1. A safety protection device, characterized in that: The device comprises: a switch, a first sampling circuit, a leakage detection circuit, a self-locking circuit and a switch control circuit, wherein: The switch is arranged on the negative loop of the circuit between the positive terminal of the mainboard power input and the negative terminal of the mainboard power input; The first sampling circuit is used to sample the negative output current at the negative terminal of the mainboard power input, and send the negative output current to the leakage detection circuit; The leakage detection circuit is used to send a leakage abnormality signal to the self-locking circuit when the negative electrode output current is greater than the leakage abnormality threshold; The self-locking circuit is used to send a shutdown control signal to the switch control circuit when receiving the leakage abnormality signal; The switch control circuit is used to control the switch to turn off when receiving the shutdown control signal.

2. The safety protection device according to claim 1, characterized in that: The device further comprises: a processing module, the first sampling circuit and the self-locking circuit are electrically connected to the processing module respectively, wherein: The first sampling circuit is further used to send the negative output current to the processing module; The processing module is used to determine whether a leakage abnormality occurs in the mainboard based on the negative electrode output current, and send the leakage abnormality signal to the self-locking circuit when a leakage abnormality occurs in the mainboard.

3. The safety protection device according to claim 2, characterized in that: The device further comprises: a second sampling circuit electrically connected to the processing module; The second sampling circuit is used to sample the positive input current at the positive terminal of the mainboard power input, and send the positive input current to the processing module; The processing module is further used to determine whether an abnormality occurs in the mainboard based on the positive input current and the negative output current, and send an abnormality signal of the mainboard to the self-locking circuit when an abnormality occurs in the mainboard; The self-locking circuit is also used to send the shutdown control signal to the switch control circuit after receiving the mainboard abnormality signal.

4. The safety protection device according to claim 2, characterized in that: The device further comprises: a recovery circuit electrically connected to the switch control circuit; The recovery circuit is used to send a switch-on control signal to the switch control circuit when receiving the recovery signal; The switch control circuit is further used to control the switch to be turned on when receiving the turn-on control signal.

5. The safety protection device according to claim 4, characterized in that: The device further comprises: a restoration signal generating module electrically connected to the leakage detection circuit; The leakage detection circuit is further configured to send a non-leakage signal to the recovery signal generation module when the negative electrode output current is not greater than the leakage abnormality threshold; The recovery signal generating module is used to generate a recovery signal based on the non-leakage signal, and send the recovery signal to the recovery circuit.

6. The safety protection device according to claim 4, characterized in that: The processing module is also used for: After receiving the leakage abnormality signal and delaying for a preset time, the recovery signal is generated, and the recovery signal is sent to the recovery circuit; wherein the leakage abnormality signal is sent by the leakage detection circuit to the processing module; And / or, generating the recovery signal after receiving the recovery instruction, and sending the recovery signal to the recovery circuit.

7. The safety protection device according to any one of claims 2 to 6, characterized in that: The device further comprises: an alarm module electrically connected to the processing module and / or the leakage detection circuit; The alarm module is used to issue an alarm when receiving the mainboard abnormality signal sent by the processing module; and / or, to issue an alarm when receiving the leakage abnormality signal sent by the leakage detection circuit.

8. A vehicle-mounted mainboard, characterized in that: include: A main body is provided with a mainboard power input positive terminal and a mainboard power input negative terminal, and a safety protection device connected to the mainboard body; wherein the safety protection device is the safety protection device described in any one of claims 1 to 7.

9. A security protection method, characterized in that: A processing module applied to a safety protection device according to any one of claims 1 to 7, the method comprising: Acquire the negative output current collected by the first sampling circuit; Based on the negative output current, determining whether an abnormality occurs in the mainboard; When an abnormality occurs to the main board, a main board abnormality signal is sent to the self-locking circuit.

10. The security protection method according to claim 9, characterized in that: The method further comprises: Obtaining the positive input current collected by the second sampling circuit; The determining whether an abnormality occurs in the mainboard based on the negative output current includes: determining whether an abnormality occurs in the mainboard based on the negative output current and the positive input current.

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