阅读说明：本技术 主负继电器检测系统 (Main and negative relay detection system ) 是由 刘鹏飞 罗乐 王俊 吴壬华 于 2020-10-21 设计创作，主要内容包括：一种主负继电器检测系统(10),该主负继电器检测系统(10)包括第一回路(100)和检测电路(110),第一回路(100)包括第一电源(DC1)、主正继电器(K1)、负载(DC2)以及主负继电器(K2),检测电路(110)包括第二电源(VCC)、第一电阻(R1)、第二电阻(R2)、第三电阻(R3)以及微控制单元(MCU),其中,第一电源(DC1)的正极连接主正继电器(K1)的正端,主正继电器(K1)的负端连接负载(DC2)的正极,负载(DC2)的负极连接主负继电器(K2)的正端,主负继电器(K2)的负端连接第一电源(DC1)的负极；第二电源(VCC)的正极连接第一电阻(R1)的第一端,第一电阻(R1)的第二端分别连接第二电阻(R2)的第一端、第三电阻(R3)的第一端及微控制单元(MCU),第二电阻(R2)的第二端分别连接主负继电器(K2)负端和第二电源(VCC)的负极,第三电阻(R3)的第二端连接主负继电器(K2)的正端。该系统有利于提高汽车的安全性。(A main negative relay detection system (10), the main negative relay detection system (10) comprises a first loop (100) and a detection circuit (110), the first loop (100) comprises a first power supply (DC1), a main positive relay (K1), a load (DC2) and a main negative relay (K2), the detection circuit (110) comprises a second power supply (VCC), a first resistor (R1), a second resistor (R2), a third resistor (R3) and a Micro Control Unit (MCU), wherein the positive pole of the first power supply (DC1) is connected with the positive pole of the main positive relay (K1), the negative pole of the main positive relay (K1) is connected with the positive pole of the load (DC2), the negative pole of the load (DC2) is connected with the positive pole of the main negative relay (K2), and the negative pole of the main negative relay (K2) is connected with the negative pole of the first power supply (DC 1); the positive pole of second power (VCC) connects the first end of first resistance (R1), the first end of second resistance (R2), the first end and the little the control unit (MCU) of third resistance (R3) are connected respectively to the second end of first resistance (R1), the negative terminal of main negative relay (K2) and the negative pole of second power (VCC) are connected respectively to the second end of second resistance (R2), the positive terminal of main negative relay (K2) is connected to the second end of third resistance (R3). The system is beneficial to improving the safety of the automobile.)

1. A main negative relay detection system is characterized by comprising a first loop and a detection circuit, wherein the first loop comprises a first power supply, a main positive relay, a load and a main negative relay, the detection circuit comprises a second power supply, a first resistor, a second resistor, a third resistor and a micro control unit, wherein,

the positive electrode of the first power supply is connected with the positive end of the main positive relay, the negative end of the main positive relay is connected with the positive electrode of the load, the negative electrode of the load is connected with the positive end of the main negative relay, and the negative end of the main negative relay is connected with the negative electrode of the first power supply;

the positive electrode of the second power supply is connected with the first end of the first resistor, the second end of the first resistor is respectively connected with the first end of the second resistor, the first end of the third resistor and the micro control unit, the second end of the second resistor is respectively connected with the negative end of the main negative relay and the negative electrode of the second power supply, and the second end of the third resistor is connected with the positive end of the main negative relay;

the micro control unit is used for detecting the voltage of the second end of the first resistor, and determining the current state of the main negative relay corresponding to the voltage according to the voltage and the mapping relation between the preset voltage and the current state of the main negative relay, wherein the current state comprises opening, closing and adhesion.

2. The main negative relay detection system of claim 1, wherein the detection circuit further comprises a first switching device in series with the second resistor and a second switching device in series with the third resistor;

the first switch device is used for connecting or disconnecting the second resistor with the negative end of the main negative relay;

the second switch device is used for connecting or disconnecting the third resistor with the positive end of the main positive relay.

3. The main negative relay detection system of claim 1, wherein the detection circuit further comprises a first one-way conductive component, wherein,

the anode of the first unidirectional conducting device is connected with the anode of the second power supply, and the cathode of the first unidirectional conducting device is connected with the first end of the first resistor;

the first unidirectional conducting device is used for conducting current in the detection circuit in a unidirectional mode so as to prevent the first power supply from influencing voltage detection.

4. The main negative relay detection system of claim 3, wherein the first unidirectional conductive component comprises a diode.

5. The main negative relay test system of any of claims 1-4, further comprising: and the protection circuit module is connected with the micro control unit.

6. The main-negative relay detection system according to claim 5, wherein the protection circuit module comprises a protection device and a voltage stabilizing device, wherein the positive pole of the voltage stabilizing device is connected with the negative pole of the first power supply, the negative pole of the voltage stabilizing device is respectively connected with the first end of the protection device and the micro control unit, and the second end of the protection device is connected with the second end of the first resistor.

7. The main negative relay detection system of claim 6, wherein the voltage regulator device comprises a voltage regulator diode.

8. The main-negative relay detection system according to claim 5, wherein the protection circuit module comprises a second one-way conduction device and a protection device, a negative electrode of the second one-way conduction device is connected with a negative electrode of the second power supply, a positive electrode of the second one-way conduction device is respectively connected with a first end of the protection device and the micro control unit, and a second end of the protection device is connected with a second end of the first resistor.

9. The main-negative relay detection system according to claim 8, wherein the protection circuit module further comprises a third one-way conduction device, an anode of the third one-way conduction device is connected to a cathode of the first power supply, and a cathode of the third one-way conduction device is connected to an anode of the second one-way conduction device.

10. The main negative relay detection system of claim 6 or 8, wherein the protection device is a fourth resistor.

Technical Field

The application relates to the technical field of automobiles, in particular to a main and negative relay detection system.

Background

With the development of the technology, the relay is widely applied to the battery of the automobile and other related devices, the relay is often adhered due to overlarge load current, electromagnetic induction and the like, and the state of the relay in the automobile technology is directly related to the safety of the automobile, so that the detection of the relay is extremely important.

In the prior art, different states of the relay are generally judged by measuring the voltage of a low-voltage coil, but the method often makes wrong judgment and has potential safety hazards.

Disclosure of Invention

In order to solve the problems, the application provides a main negative relay detection system which can accurately judge the current state of a main negative relay and improve the safety of an automobile.

The embodiment of the application provides a main negative relay detection system, which comprises a first loop and a detection circuit, wherein the first loop comprises a first power supply, a main positive relay, a load and a main negative relay, the detection circuit comprises a second power supply, a first resistor, a second resistor, a third resistor and a micro control unit, wherein,

the positive electrode of the first power supply is connected with the positive end of the main positive relay, the negative end of the main positive relay is connected with the positive electrode of the load, the negative electrode of the load is connected with the positive end of the main negative relay, and the negative end of the main negative relay is connected with the negative electrode of the first power supply;

the positive electrode of the second power supply is connected with the first end of the first resistor, the second end of the first resistor is respectively connected with the first end of the second resistor, the first end of the third resistor and the micro control unit, the second end of the second resistor is respectively connected with the negative end of the main negative relay and the negative electrode of the second power supply, and the second end of the third resistor is connected with the positive end of the main negative relay;

the micro control unit is used for detecting the voltage of the second end of the first resistor, and determining the current state of the main negative relay corresponding to the voltage according to the voltage and the mapping relation between the preset voltage and the current state of the main negative relay, wherein the current state comprises opening, closing and adhesion.

In one embodiment, the detection circuit further comprises a first switching device in series with the second resistor and a second switching device in series with the third resistor;

the first switch device is used for connecting or disconnecting the second resistor with the negative end of the main negative relay;

the second switch device is used for connecting or disconnecting the third resistor with the positive end of the main positive relay.

In one embodiment, the detection circuit further comprises a first unidirectional conducting component, wherein,

the anode of the first unidirectional conducting device is connected with the anode of the second power supply, and the cathode of the first unidirectional conducting device is connected with the first end of the first resistor;

the first unidirectional conducting device is used for conducting current in the detection circuit in a unidirectional mode so as to prevent the first power supply from influencing voltage detection.

In one embodiment, the first unidirectional conducting component comprises a diode.

In one embodiment, the main negative relay detection system further comprises: and the protection circuit module is connected with the micro control unit.

In one embodiment, the protection circuit module comprises a protection device and a voltage stabilizing device, wherein the anode of the voltage stabilizing device is connected with the cathode of the first power supply, the cathode of the voltage stabilizing device is respectively connected with the first end of the protection device and the micro control unit, and the second end of the protection device is connected with the second end of the first resistor.

In one embodiment, the voltage regulator device includes a zener diode.

In one embodiment, the protection circuit module includes a second unidirectional conducting device and a protection device, a negative electrode of the second unidirectional conducting device is connected to a negative electrode of the second power supply, a positive electrode of the second unidirectional conducting device is respectively connected to the first end of the protection device and the micro control unit, and a second end of the protection device is connected to the second end of the first resistor.

In one embodiment, the protection circuit module further includes a third unidirectional conducting device, an anode of the third unidirectional conducting device is connected to a cathode of the first power supply, and a cathode of the third unidirectional conducting device is connected to an anode of the second unidirectional conducting device.

In one embodiment, the protection device is a fourth resistor.

In this application, main negative relay detecting system includes first return circuit and detection circuitry, first return circuit is including the first power that establishes ties in proper order, main positive relay, load and main negative relay, detection circuitry includes the second power, first resistance, the second resistance, third resistance and little the control unit, the first end of first resistance is connected to the positive pole of second power, the first end of second resistance is connected respectively to the second end of first resistance, the first end and the little the control unit of third resistance, the negative pole of main negative relay negative terminal and second power is connected respectively to the second end of second resistance, the main negative relay positive terminal is connected to the second end of third resistance. Therefore, the main negative relay detection system can accurately detect different states of the main negative relay by using the external power supply under the condition that the first loop is not connected with the first power supply by connecting the external power supply into the detection circuit, and the safety of the automobile is improved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments or the background art of the present application, the drawings referred to in the embodiments or the background art of the present application will be briefly described below.

Reference will now be made in brief to the accompanying drawings, to which embodiments of the present application relate.

Fig. 1 is a schematic structural diagram of a main and negative relay detection system provided in this embodiment;

fig. 2 is a schematic structural diagram of another main negative relay detection system provided in this embodiment;

fig. 3 is a schematic structural diagram of another main negative relay detection system provided in this embodiment;

fig. 4 is a schematic structural diagram of a protection circuit module according to this embodiment;

fig. 5 is a schematic structural diagram of another protection circuit module provided in this embodiment;

fig. 6 is a schematic structural diagram of another protection circuit module provided in this embodiment.

Detailed Description

In order to make the technical solutions better understood by those skilled in the art, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only partial embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The following are detailed below.

The terms "first," "second," "third," and "fourth," etc. in the description and claims of this application and in the accompanying drawings are used for distinguishing between different objects and not for describing a particular order. Furthermore, the term "comprises" and any variations thereof is intended to cover non-exclusive inclusions. For example, a system that includes a list of modules and devices is not limited to those listed, but may alternatively include modules and devices not listed, or may alternatively include other modules and devices inherent to such systems.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a main negative relay detection system provided in an embodiment of the present application, as shown in fig. 1, the main negative relay detection system 10 includes a first circuit 100 and a detection circuit 110, the first circuit 100 includes a first power source DC1, a main positive relay K1, a load DC2 and a main negative relay K2, the detection circuit 110 includes a second power source VCC, a first resistor R1, a second resistor R2, a third resistor R3 and a micro control unit MCU, wherein a positive electrode of the first power source DC1 is connected to a positive terminal of the main positive relay K1, a negative electrode of the main positive relay K1 is connected to a positive electrode of the load DC2, a negative electrode of the load DC2 is connected to a positive terminal of the main negative relay K2, and a negative electrode of the main negative relay K2 is connected to a negative electrode of the first power source DC 1; the positive electrode of the second power supply VCC is connected with the first end of the first resistor R1, the second end of the first resistor R1 is respectively connected with the first end of the second resistor R2, the first end of the third resistor R3 and the micro control unit MCU, the second end of the second resistor R2 is respectively connected with the negative end of the main negative relay K2 and the negative end of the second power supply VCC, and the second end of the third resistor R3 is connected with the positive end of the main negative relay K2; the micro control unit MCU is used for detecting the voltage of the second end of the first resistor R1, and determining the current state of the main negative relay K2 corresponding to the voltage according to the voltage and the mapping relation between the preset voltage and the current state of the main negative relay K2, wherein the current state comprises opening, closing and adhesion.

In the first circuit 100, the first power supply DC1 provides a power supply voltage, the first power supply DC1 may be a DC power supply, the first power supply DC1 may also be a DC power supply formed by rectifying a current generated by an ac generator, for example, the first power supply DC1 may be a power battery, the first power supply DC1 may also be a storage battery, the load DC2 may be a control device connected between the first power supply DC1 and various power consuming devices, such as a whole vehicle controller or an integrated motor controller, the load DC2 may also be a conversion device connected between the first power supply DC1 and various power consuming devices, such as an on-board charger output, a DC-DC converter input, or a fast charging interface, the load DC2 may also be a power consuming device, such as a heater, and the load DC2 is not particularly limited herein, in the same first circuit 100, the first power source DC1 and the load DC2 have a corresponding relationship, where different first power sources DC1 correspond to different load DC2, and the same first power source DC1 may correspond to different load DC2, for example, the first power source DC1 is a power battery, and the load DC2 is an output of an in-vehicle charger; the first power supply DC1 is a storage battery, and the load DC2 is output by an on-board charger; the first power supply DC1 is a battery, and the load DC2 is a whole vehicle controller; the first power supply DC1 is a battery, and the load DC2 is a quick charging interface; the first power supply DC1 is a thermostatic controller, and the load DC2 is a heater; the first power source DC1 is an integrated motor controller and the DC2 is a DC-DC converter input. Of course, the first power source DC1 and the load DC2 may be other corresponding devices, and are not particularly limited.

As can be seen from the above, in the first circuit 100, the relays (including the main positive relay K1 and the main negative relay K2) may be a relay between the power battery and the output of the vehicle-mounted charger, a relay between the storage battery and the output of the vehicle-mounted charger, a relay between the battery and the vehicle controller and the quick charging interface, a relay between the thermostat controller and the heater, a relay between the integrated motor controller and the DC-DC converter, and other relays that may have a corresponding relationship between the first power source DC1 and the load DC2, where the relays may be an electromagnetic relay or a dry-reed relay, the main positive relay K1 and the main negative relay K2 may be the same relay or different relays, and are not specifically limited, for example, the main positive relay K1 is an electromagnetic relay, the main negative relay K2 is a reed relay, and for example, the main positive relay K1 and the main negative relay K2 are both reed relays.

In the detection circuit 110, the second power VCC may be a DC voltage source, and when the first power DC1 does not provide power to the first circuit 100, that is, the DC1 is not turned on, an external power is provided to the detection circuit 110, so as to detect the current state of the main negative relay K2 in the first circuit 100, where the resistors (including the first resistor R1, the second resistor R2, and the third resistor R3) may be fixed resistors or variable resistors.

When the detection is carried out, the first power supply DC1 is disconnected, the second power supply VCC is used for supplying power, the voltage of the second end of the first resistor R1 is detected through the micro control unit MCU, and if the main negative relay K2 is disconnected, the voltage of the second end of the first resistor R1 is [ X [ ]₂/(X₁+X₂)]U; if the main negative relay K2 is closed, the voltage at the second end of the first resistor R1 is [ X ]₃/(X₁+X₃)]U，X₃＝[X₂(X₄+X₅)]/(X₂+X₄+X₅) (ii) a If the main negative relay K2 is stuck, the voltage at the second end of the first resistor R1 is [ X ]₆/(X₁+X₆)]U，X₆＝[X₂(X₇+X₅)]/(X₂+X₇+X₅)；X₁Is the resistance value, X, of the first resistor R1₂Is the resistance value of the second resistor R2, U is the voltage value provided by the second power supply VCC, X₃The resistance values X corresponding to the resistances of the second resistor R2, the third resistor R3 and the main negative relay K2 when the main negative relay K2 is closed as a whole₄Is the resistance value, X, corresponding to the resistance when the main negative relay K2 is closed₅Is the resistance value, X, of the third resistor R3₆The resistors when the main negative relay K2 is adhered and the second resistor R2, the third resistor R3 and the main negative relay K2 are adhered and correspond to the resistors when the main negative relay K2 is adhered and the main negative relay K2 is adhered as a wholeResistance value, X₇The resistance value is corresponding to the resistance when the main negative relay K2 is adhered. It should be noted that the closing of the relay means that the relay is turned on, and in appearance, the relay can be considered to be directly connected through a wire; sticking of the relay indicates that the contacts are engaged (meaning that current can flow), but may have a higher resistance, but also means that the relay is on. Therefore, when the main negative relay K2 is turned off, the voltage at the second end of the first resistor R1 corresponds to the voltage divided by the second resistor R2, when the main negative relay K2 is closed, the voltage at the second end of the first resistor R1 corresponds to the voltage divided by the second resistor R2 connected in series to the third resistor R3 and the resistor when the main negative relay K2 is closed, when the main negative relay K2 is turned off, the voltage at the second end of the first resistor R2 corresponds to the voltage divided by the second resistor R2 connected in parallel to the resistor formed by connecting the third resistor R3 and the resistor when the main negative relay K2 is closed in series, when the main negative relay K2 is turned off, the voltage at the second end of the second resistor R2 connected in series to the resistor R3 and the resistor when the main negative relay K2 are stuck, the voltage at the second end of the first resistor R1 is equivalent to the voltage obtained by connecting the second resistor R2, the third resistor R3 and the resistor connected in series when the main negative relay K2 is adhered, and further, the voltage at the second end of the first resistor R1 when the main negative relay K2 is opened is larger than the voltage at the second end of the first resistor R1 when the main negative relay K2 is closed, and the voltage at the second end of the first resistor R1 when the main negative relay K2 is closed is larger than the voltage at the second end of the first resistor R1 when the main negative relay K2 is adhered, wherein [ X1 ] is defined as₂/(X₁+X₂)]U、[X₃/(X₁+X₃)]U、[X₆/(X₁+X₆)]U is only a theoretical calculation, and in practical applications, the voltage at the second end of the first resistor R1 is in a voltage range corresponding to different states of the main negative relay K2, and this range can be obtained through a large number of experiments and stored as reference data in the MCU,the voltage range of the measured voltage of the second end of the first resistor R1 is determined through the MCU, and then the current state of the main and negative relay K2 is determined.

It can be seen that, the main and negative relay detection system 10 provided in the embodiment of the present application can realize that different states of the main and negative relay K2 are accurately detected by using the external power supply when the first power supply DC1 does not supply power to the first loop 100 by accessing the external power supply (i.e., the second power supply VCC) in the detection circuit 110, thereby improving the safety of the vehicle.

Referring to fig. 2, fig. 2 is a schematic structural diagram of another main-negative relay inspection system according to an embodiment of the present disclosure, as shown in fig. 2, a first switching device K3 and a second switching device K4 are added to an inspection circuit 210 in the main-negative relay inspection system 10 provided in fig. 1, the first switching device K3 is connected in series with the second resistor R2, and the second switching device K4 is connected in series with the third resistor R3; the first switching device K3 is used for switching on or off the connection of the second resistor R2 and the negative end of the main negative relay K2; the second switching device K4 is used to connect or disconnect the third resistor R3 to the positive terminal of the main positive relay K1. The circuit structure of the rest part is the same as that of fig. 1, please refer to the above description for fig. 1, and will not be repeated herein.

In the detection circuit 210, the switch device (including the first switch device K3 and the second switch device K4) may be a physical switch device, and the switch device may also be a virtual function key, and if the switch device is a physical switch device, the switch device may be disposed on the device of the MCU, and if the switch device is a virtual function key, the switch device may be disposed on a display interface of the MCU, which has a display function.

In practical applications, when the first power supply DC1 in the first loop 100 is not supplying power, the micro control unit MCU controls the first switching device K3 and the second switching device K4 to measure a required voltage value at the second end of the first resistor R1, so as to determine the state of the main negative relay K2.

When the first switching device K3 is closed and the second switching device K4 is opened, the voltage measured by the MCU is the voltage divided by the second resistor R2 after the first resistor R1 is connected in series with the second resistor R2;

when the first switching device K3 is turned off and the second switching device K4 is turned on, if the main negative relay K2 is turned off, the voltage measured by the micro control unit MCU is the output voltage of the second power source VCC, and if the main negative relay K2 is turned on, the voltage measured by the micro control unit MCU is the voltage obtained by the common division of the resistances when the first resistor R1, the third resistor R3 and the main negative relay K2 are connected in series, and when the third resistor R3 and the main negative relay K2 are turned on; if the main negative relay K2 is adhered, the voltage measured by the MCU is the voltage obtained by the common division of the resistors when the first resistor R1, the third resistor R3 and the resistor when the main negative relay K2 is adhered are connected in series, the third resistor R3 and the main negative relay K2 are adhered;

when the first switching device K3 and the second switching device K4 are closed, if the main negative relay K2 is open, the MCU is a voltage obtained by connecting the first resistor R1 and the second resistor R2 in series and then dividing the second resistor R2; if the main negative relay K2 is closed, the voltage measured by the MCU is the voltage divided by the second resistor R2 in parallel with the third resistor R3 and the resistor when the main negative relay K2 is closed, wherein the third resistor R2 is connected in series with the third resistor R3526; if the main negative relay K2 is stuck, the voltage measured by the micro control unit MCU is the voltage obtained by parallel connection of the second resistor R2 and the resistors when the third resistor R3 and the main negative relay K2 which are connected in series are stuck.

In practical applications, different relationship lists can be set in the MCU, the relationship lists can reflect the corresponding relationship between the states of the first switching device K3, the second switching device K4, the main negative relay K2 and the voltage at the second end of the first resistor R1, during the voltage detection, the state of the main negative relay K2 can be determined according to the states of the first switching device K3 and the second switching device K4 and the measured voltage at the second end of the first resistor R1, and the states of the first switching device K3 and the second switching device K4 can be changed by the MCU under the condition that the state of the main negative relay K2 cannot be determined according to the states of the first switching device K3 and the second switching device K4 and the measured voltage at the second end of the first resistor R1, further analyzing the changed states of the first switching device K3, the second switching device K4 and the corresponding detection results to determine the state of the main negative relay K2, or further combining the situation when the states of the first switching device K3 and the second switching device K4 are not identical to determine the state of the main negative relay K2.

In this example, the main and negative relay detection system 20 obtains the voltage detection result by setting a switch device to control the detection circuit 210 to access the main and negative relay K2, and determines the current state of the main and negative relay K2 according to the voltage detection result, so that convenience in detecting the state of the main and negative relay K2 is improved.

Referring to fig. 3, fig. 3 is a schematic structural diagram of another main negative relay detection system provided in the embodiment of the present application, as shown in fig. 3, a first unidirectional conducting component D1 is added to the detection circuit 310 of the main negative relay detection system 10 provided in fig. 1 by the detection circuit 310 in the main negative relay detection system 30, the positive electrode of the second power source VCC is connected to the positive electrode of the first unidirectional conducting component D1, and the negative electrode of the first unidirectional conducting component D1 is connected to the first end of the first resistor R1; the first unidirectional conducting component D1 is configured to conduct the current in the detection circuit 310 in a unidirectional manner, so as to avoid affecting the voltage detection result of the MCU under the condition of power supply from the first power supply DC 1.

Wherein the first unidirectional conducting component D1 may be a diode. When the first power supply DC1 provides a voltage to the first loop 100 to generate a current, and the second power supply VCC provides a voltage to the detection circuit 310 to generate a current, if the first unidirectional conducting component D1 is not provided, as shown in fig. 1, the current generated when the first power supply DC1 provides a voltage to the first loop 100 flows to the second power supply VCC to affect the second power supply VCC, and further affects the voltage at the second end of the first resistor R1 to be detected, but the first unidirectional conducting component D1 is added, as shown in fig. 3, because the first unidirectional conducting component D1 is conducting in the forward direction and non-conducting in the reverse direction, the current in the detection circuit 310 is not affected by the first power supply DC 1.

It should be noted that the first unidirectional conducting component D1 can be applied to the detection circuit 210 in fig. 2, and the setting position refers to fig. 3, and the principle thereof is the same as that described for fig. 3, and is not described herein again.

In this example, the main and negative relay detection system 30 adds the first one-way conduction device D1 to the detection circuit 110 of the main and negative relay detection system 10 to avoid the influence of the first power supply DC1 in the first loop 100 on the detection circuit 310, so that the detection circuit 310 can normally operate even when the first power supply DC1 in the first loop 100 operates, thereby improving the convenience of detecting the main and negative relay K2.

In a possible embodiment, said first unidirectional conducting component D1 comprises a diode.

The diode may be a silicon diode or a germanium diode, and the diode allows current to pass through in a single direction (referred to as forward bias) and blocks (referred to as reverse bias) reverse current, that is, the diode allows current flowing from the second power source VCC (external current) to pass through.

In one possible embodiment, any one of the main negative relay detection systems shown in fig. 1, 2, and 3 further includes: and the protection circuit module is connected with the MCU.

The protection circuit module is used for protecting the MCU.

Specifically, the protection circuit module can limit the voltage of the second end of the second resistor R2.

Referring to fig. 4, fig. 4 is a schematic structural diagram of a protection circuit module provided in this embodiment, as shown in fig. 4, the protection circuit module includes a protection device 400 and a voltage regulator device 401, an anode of the voltage regulator device 401 is connected to a cathode of the first power supply DC1, cathodes of the voltage regulator device 401 are respectively connected to a first end of the protection device 400 and the MCU, and a second end of the protection device 400 is connected to a second end of the first resistor R1.

The protection device 400 may be a resistor, and the voltage regulator device 401 may be a voltage regulator diode, where the voltage regulator diode and the resistor stabilize the voltage together, when the reverse voltage reaches a certain degree, the normal diode may be broken down in the reverse direction, and the voltage regulator diode may prevent the voltage from increasing continuously by allowing a large current to flow in the reverse direction.

For example, when the voltage at the second end of the first resistor R1 is too high, the direct connection to the MCU may cause the chip in the MCU to be burned out, and at this time, the presence of the protection device 400 and the voltage regulator device 401 enables the protection device 400 to reduce the input voltage of the MCU and the voltage regulator device 401 to conduct a large current in the reverse direction, so that the input voltage of the MCU will not rise further, thereby protecting the MCU.

Referring to fig. 5, fig. 5 is a schematic structural diagram of another protection circuit module provided in this embodiment, as shown in fig. 5, the protection circuit module includes a second unidirectional conducting device D2 and a protection device 500, a cathode of the second unidirectional conducting device D2 is connected to a cathode of the second power source VCC, an anode of the second unidirectional conducting device D1 is respectively connected to a first end of the protection device 500 and the MCU, and a second end of the protection device 500 is connected to a second end of the first resistor R1.

The second unidirectional conducting device D2 may be a diode, and the protection device 500 may be a resistor, where if the forward voltage is smaller than a certain value, the diode has a large resistance and does not affect the flow of current, but if the forward voltage exceeds or equals to the certain value, the diode is turned on, and the current flows to the cathode of the second power source VCC through the diode, so as to protect the MCU from being damaged by the excessive MCU input voltage.

Referring to fig. 6, fig. 6 is a schematic structural diagram of another protection circuit module provided in this embodiment, in the protection circuit module shown in fig. 6, a third unidirectional conducting device D3 is added on the basis of the protection circuit module shown in fig. 5, as shown in fig. 6, a positive electrode of the third unidirectional conducting device D3 is connected to a negative electrode of the first power supply DC1, and a negative electrode of the third unidirectional conducting device D3 is connected to a positive electrode of the second unidirectional conducting device D2.

Wherein the third unidirectional conducting device D3 may be a diode.

When the voltage value of the second end of the protection device 600 is higher than the turn-on voltage value U1 of the second unidirectional conducting device D2 and lower than the breakdown voltage U2 of the third unidirectional conducting device D3, U1 is smaller than U2, current can flow through the circuit where the second unidirectional conducting device D2 is located, and when the voltage value of the second end of the protection device 600 is higher than or equal to the breakdown voltage U2 of the third unidirectional conducting device D3, current can flow through the circuit where the second unidirectional conducting device D2 and the third unidirectional conducting device D3 are located, so that the protection circuit module shown in fig. 6 can prevent the MCU from being damaged by an excessively high MCU input voltage.

In the foregoing embodiments, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments.

The foregoing detailed description of the embodiments of the present application has been presented to illustrate the principles and implementations of the present application with specific examples, and the above description of the embodiments is only provided to help understand the present application and its core ideas; meanwhile, for a person skilled in the art, according to the idea of the present application, there may be variations in the specific implementation and application scope, and in summary, the content of the present specification should not be construed as a limitation to the present application.