Detection circuit and detection device of relay
By setting a detection circuit with a reference unit, a sampling unit, and a protection unit at both ends of the relay, the complexity and safety issues of the negative relay detection circuit are solved, achieving the effects of simplifying the structure, reducing costs, and improving detection accuracy.
Patent Information
- Application Number
- CN202423082803.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-12
- Publication Date
- 2025-12-02
- Estimated Expiration
- 2034-12-12
AI Technical Summary
Existing negative terminal relay detection circuits are complex, costly, and difficult to guarantee in terms of safety. They are particularly prone to damage under high voltage dynamic potential conditions, affecting the reliability and safety of the battery pack.
A relay detection circuit was designed. By setting a reference unit, a first sampling unit, a second sampling unit, and a protection unit at both ends of the relay, the relay state is determined by the voltage difference. This simplifies the circuit structure, provides a stable reference voltage, avoids direct coupling between the negative terminal of the battery and the low-voltage ground, and prevents reverse current from damaging the components.
This simplifies the detection circuit structure, reduces circuit complexity and cost, improves detection accuracy and safety, prevents component damage, and ensures the reliability and safety of the battery pack.
Smart Images
Figure CN223624378U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the technical field of relays, and in particular to a relay detection circuit and detection device. Background Technology
[0002] In applications such as new energy vehicles and energy storage systems, the long-term operation of battery packs requires reliable relays to control the output and input of electrical energy. Especially under extreme conditions such as high temperature, low temperature, and prolonged charge and discharge, relays are prone to sticking or damage due to mechanical or electrical fatigue, which may lead to unexpected discharge of the battery pack. This situation not only reduces the performance and reliability of the system, but may also pose a serious threat to equipment and personal safety.
[0003] Typically, the positive terminal of the battery pack is connected to the load via a positive relay to control the positive circuit, while the negative terminal is connected to the load via a negative relay to control the negative circuit. For diagnosing the negative relay, existing technologies often design the detection circuit with a low-voltage ground as the reference point. However, since the negative relay is directly connected to the negative terminal of the battery pack, and the negative terminal may have high voltage or dynamic potential, this detection circuit usually requires additional electrical isolation components (such as optocouplers or isolation transformers) to ensure system safety and prevent direct coupling between the low-voltage ground and the high-voltage battery system. This significantly increases the complexity and cost of the circuit. Furthermore, because isolation, safety, and dynamic voltage interference must be considered simultaneously, the existing negative relay detection circuit design logic is complex, difficult to debug, and costly. Utility Model Content
[0004] The present invention provides a detection circuit and detection device for a relay, which effectively improves the defects of the existing detection circuit of the negative terminal relay.
[0005] To solve the above-mentioned technical problems, the embodiments of this utility model disclose the following technical solutions:
[0006] On the one hand, a detection circuit for a relay is provided, having a first terminal and a second terminal, wherein the first terminal is connected to a path between a battery and a relay, and the second terminal is connected to a path between a load and a relay;
[0007] The detection circuit of the relay includes:
[0008] Reference unit, used to provide reference voltage;
[0009] A first sampling unit is connected between a reference unit and the first terminal. The first sampling unit has a first sampling point at one end connected to the reference unit and is used to output a first sampling voltage.
[0010] The second sampling unit is connected between the first sampling point and the second terminal. The second sampling unit is used to connect to the second terminal. One end is provided with a second sampling point for outputting a second sampling voltage.
[0011] A protection unit is connected in series between the second sampling unit and the second terminal to conduct the first current between the second sampling unit and the second terminal in a one-way manner. The first current can only flow from the second sampling point to the second terminal.
[0012] The state of the relay is determined based on the voltage difference between the first sampling voltage and the second sampling voltage, and the state of the relay includes open or closed.
[0013] In addition to one or more of the features disclosed above, or as an alternative, the reference unit includes a reference power supply and a pull-up resistor, one end of which is connected to the reference power supply and the other end of which is connected to the output of the reference unit.
[0014] In addition to one or more of the features disclosed above, or alternatively, the voltage of the reference power supply is 5V.
[0015] In addition to one or more of the features disclosed above, or as an alternative, the first sampling unit includes a first sampling resistor, one end of which is connected to the output terminal of the reference unit, and the other end of which is connected to the first terminal.
[0016] In addition to one or more of the features disclosed above, or as an alternative, the second sampling unit includes a second sampling resistor, one end of which is connected to one end of the first sampling resistor used for connection to the reference unit, and the other end of which is used for connection to the second end.
[0017] In addition to one or more of the features disclosed above, or as an alternative, the protection unit includes a Schottky diode, the positive terminal of which is connected to one end of the second sampling resistor for connection to the second terminal, and the negative terminal of which is connected to the second terminal.
[0018] In addition to one or more of the features disclosed above, or as an alternative, the protection unit includes a plurality of Schottky diodes connected in series between the second sampling resistor and the second terminal.
[0019] In addition to one or more of the features disclosed above, or alternatively, a balancing resistor is connected in series between the Schottky diode and the second terminal;
[0020] When multiple Schottky diodes are provided, the balancing resistor is connected in series between the Schottky diode adjacent to the second terminal and the second terminal.
[0021] In addition to one or more of the features disclosed above, or as an alternative, the relay is determined to be in an open state when the voltage value of the first sampling voltage is equal to the voltage value of the second sampling voltage; and the relay is determined to be in a closed state when the voltage difference between the first sampling voltage and the second sampling voltage falls within a preset voltage difference range.
[0022] In addition to one or more of the features disclosed above, or alternatively, the preset differential voltage range is determined based on the resistance values of the pull-up resistor, the first sampling resistor, the second sampling resistor, and the balancing resistor.
[0023] On the other hand, a detection device is provided, comprising a detection circuit of any of the relays described above.
[0024] One of the above technical solutions has the following advantages or beneficial effects: This application integrates the first sampling unit and the second sampling unit into the same detection circuit at both ends of the relay. During the detection process, the first sampling point and the second sampling point exhibit different voltage characteristics when the relay is closed and open. By measuring the voltage difference between the first sampling point and the second sampling point, the state of the relay (open or closed) can be accurately determined. This design effectively simplifies the structure of the detection circuit. Furthermore, this application provides a stable reference voltage through the reference unit, replacing the low-voltage ground as the reference point, effectively avoiding direct coupling between the battery negative terminal and the low-voltage ground, further reducing the complexity of the circuit. Moreover, this application also effectively prevents reverse current or transient overvoltage from damaging the sampling unit and other components through the unidirectional conduction performance of the protection unit. Attached Figure Description
[0025] The technical solution and other beneficial effects of this utility model will become apparent from the following detailed description of specific embodiments in conjunction with the accompanying drawings.
[0026] Figure 1 This is a schematic diagram of the application of a relay detection circuit according to an embodiment of this application.
[0027] Figure 2 This is a schematic diagram of the structure of a relay detection circuit according to an embodiment of this application.
[0028] Explanation of reference numerals in the attached figures:
[0029] 100. Reference element;
[0030] 200, First sampling unit; 201, First sampling point;
[0031] 300, Second sampling unit; 301, Second sampling point;
[0032] 400. Protection Unit. Detailed Implementation
[0033] To make the objectives, technical solutions, and beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described in this specification are merely for explaining the present utility model and are not intended to limit the present utility model.
[0034] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.
[0035] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, a direct connection, or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.
[0036] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0037] This utility model discloses a detection circuit for a relay, referring to... Figure 1 The detection circuit of the relay is coupled to the relay under test, which is connected in series between the battery and the load. (Refer to...) Figure 2 The relay's detection circuit has a first terminal B- and a second terminal P-. The first terminal B- is used to connect to the path between the battery and the relay, and the second terminal P- is used to connect to the path between the load and the relay. The relay's detection circuit includes a reference unit 100, a first sampling unit 200, a second sampling unit 300, and a protection unit 400. The reference unit 100 provides a reference voltage for the first sampling unit 200 and the second sampling unit 300. The first sampling unit 200 is connected between the reference unit 100 and the first terminal B-, and the end of the first sampling unit 200 connected to the reference unit 100 has a first sampling point 201 for outputting a first sampling voltage. The second sampling unit 300 is connected between the first sampling point 201 and the second terminal P-, and the end of the second sampling unit 300 connected to the second terminal P- has a second sampling point 301 for outputting a second sampling voltage. The protection unit 400 is connected in series between the second sampling unit 300 and the second terminal P-, and is used to unidirectionally conduct the first current between the second sampling unit 300 and the second terminal P-, so that the first current can only flow from the second sampling point 301 to the second terminal P-.
[0038] By setting up the same detection circuit at both ends of the relay, this application integrates the first sampling unit 200 and the second sampling unit 300 into the detection circuit. During the detection process, the first sampling point 201 and the second sampling point 301 will exhibit different voltage characteristics when the relay is closed and open. By measuring the voltage difference between the first sampling point 201 and the second sampling point 301, the state of the relay (open or closed) can be accurately determined. This design effectively simplifies the structure of the detection circuit. Furthermore, this application provides a stable reference voltage through the reference unit 100, replacing the low-voltage ground as the reference point, effectively avoiding direct coupling between the battery negative terminal and the low-voltage ground, further reducing the complexity of the circuit. In addition, this application also effectively prevents reverse current or transient overvoltage from damaging the sampling unit and other components through the unidirectional conduction performance of the protection unit 400.
[0039] In some embodiments, the reference unit 100 includes a reference power supply and a pull-up resistor R1. One end of the pull-up resistor R1 is connected to the reference power supply, and the other end is connected to the output terminal of the reference unit 100. The pull-up resistor R1 "pulls" the voltage of the reference power supply to the output terminal of the reference unit 100, ensuring that the port is at a predetermined stable voltage value. By limiting current flow, it ensures that the output terminal of the reference unit 100 will not experience voltage fluctuations due to excessive current or load changes, thereby guaranteeing the stability of the reference voltage. Furthermore, in practical applications, external voltage signals (such as battery dynamic voltage) may fluctuate due to load changes, charging and discharging processes, etc. (For example, the battery voltage may drop from a high voltage to a lower voltage as the charging and discharging state changes, or dynamic loads may cause high-frequency potential fluctuations). If the reference voltage is directly derived from the battery terminal, these fluctuations may cause the sampling voltage to be unstable, or even exceed the recognition range of subsequent analog-to-digital converters or other components (for example, analog-to-digital converters can typically only process 0-5V signals, but the battery voltage may reach 10V or higher, exceeding the recognition range of the analog-to-digital converter). The output of the reference unit 100 in this application provides a stable reference voltage, which can avoid the detection being affected by the aforementioned fluctuations and improve the detection accuracy of the detection circuit. Meanwhile, in some embodiments, the reference power supply voltage is 5V, which ensures that the range of the first and second sampling voltages after voltage division is always between 0-5V, thus always falling within the recognition range of the analog-to-digital converter or other components.
[0040] In some embodiments, the first sampling unit 200 includes a first sampling resistor R2, one end of which is connected to the output terminal of the reference unit 100, and the other end is connected to the first terminal B-. The second sampling unit 300 includes a second sampling resistor R3, one end of which is connected to the end of the first sampling resistor R2 connected to the reference unit 100, and the other end is used to connect to the second terminal P-. When the voltage of the reference power supply is 5V, when the relay is in the open state, the first sampling voltage output by the first sampling point 201 is 5V. After being divided by the pull-up resistor R1 and the first sampling resistor R2, the voltage value is obtained. At the same time, because the relay is in the open state, the voltage of the second sampling point 301 is equal to the voltage of the first sampling point 201, and the voltage difference between the first sampling voltage and the second sampling voltage is 0V. When the relay is in the closed state, the voltage of the second sampling point 301 is not zero. By comparing the voltage difference between the collected first sampling voltage and the second sampling voltage with a preset voltage difference range, it can be determined whether the relay is closed.
[0041] Further, in some embodiments, the protection unit 400 includes a Schottky diode D1. The positive terminal of the Schottky diode D1 is connected to the end of the second sampling resistor R3 that is connected to the second terminal P-, and the negative terminal is connected to the second terminal P-. The Schottky diode D1 ensures that when a reverse current occurs at the second terminal P- (e.g., potential fluctuations caused by load-side abnormalities or external interference), the reverse current cannot flow back to the sampling circuit, thereby protecting the sampling resistor and other sensitive components from damage. In some embodiments, multiple Schottky diodes D1 are provided, and multiple Schottky diodes D1 are connected in series between the second sampling resistor R3 and the second terminal P-. Connecting multiple Schottky diodes D1 in series between the second sampling resistor R3 and the second terminal P- can accommodate a higher dynamic voltage range and prevent reverse voltage from damaging the sampling unit. In some embodiments, the protection unit 400 also includes a balancing resistor R4 connected in series between the Schottky diode D1 and the second terminal P-. Specifically, when multiple Schottky diodes D1 are provided, the balancing resistor R4 is connected in series between the Schottky diode D1 adjacent to the second terminal P- and the second terminal P-.
[0042] It should be noted that when the relay is in the closed state, the preset voltage difference between the first sampling voltage and the second sampling voltage is determined based on the resistance values of the pull-up resistor, the first sampling resistor R2, the second sampling resistor R3, and the balancing resistor R4. Specifically, when the relay is in the closed state, the branch containing the first sampling unit 200 and the branch containing the second sampling unit 300 and the protection unit 400 are essentially connected in parallel. Based on the nodal current method, formula one related to V1 can be obtained:
[0043]
[0044] Using the principle of voltage division by resistors, we can obtain Formula 2 related to V1 and V2:
[0045]
[0046] Based on Formula 1 and Formula 2, Formula 3 for V1-V2 can be obtained:
[0047]
[0048] Where V1 is the voltage value of the first sampling voltage, V2 is the voltage value of the second sampling voltage, R1 is the resistance value of the pull-up resistor, R2 is the resistance value of the first sampling resistor, R3 is the resistance value of the second sampling resistor, R4 is the resistance value of the balancing resistor, and VD is the voltage drop of the Schottky diode D1. The preset voltage difference value can be determined using Formula 3. Based on the preset voltage difference value, the preset voltage difference range can be determined. The preset voltage difference range is typically within 0.2V above and below the preset voltage difference value.
[0049] This utility model embodiment also discloses a detection device, which includes the detection circuit of any of the above-mentioned relays.
[0050] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0051] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.
Claims
1. A detection circuit for a relay, coupled to a relay to be tested, the relay to be tested being connected in series between a battery and a load, characterized in that, It has a first end and a second end, the first end being coupled to a path between a battery and a relay, and the second end being coupled to a path between a load and a relay; The detection circuit of the relay includes: Reference unit, used to provide reference voltage; A first sampling unit is connected between a reference unit and the first terminal. The first sampling unit has a first sampling point at one end connected to the reference unit and is used to output a first sampling voltage. The second sampling unit is connected between the first sampling point and the second terminal. The second sampling unit is used to connect to the second terminal. One end is provided with a second sampling point for outputting a second sampling voltage. A protection unit is connected in series between the second sampling unit and the second terminal to conduct the first current between the second sampling unit and the second terminal in a one-way manner. The first current can only flow from the second sampling point to the second terminal. The state of the relay is determined based on the voltage difference between the first sampling voltage and the second sampling voltage, and the state of the relay includes open or closed.
2. The detection circuit of the relay according to claim 1, characterized in that, The reference unit includes a reference power supply and a pull-up resistor. One end of the pull-up resistor is connected to the reference power supply, and the other end is connected to the output terminal of the reference unit.
3. The detection circuit of the relay according to claim 2, characterized in that, The voltage of the reference power supply is 5V.
4. The detection circuit of the relay according to claim 2, characterized in that, The first sampling unit includes a first sampling resistor, one end of which is connected to the output terminal of the reference unit, and the other end is connected to the first terminal.
5. The detection circuit of the relay according to claim 4, characterized in that, The second sampling unit includes a second sampling resistor, one end of which is connected to one end of the first sampling resistor used for connection to the reference unit, and the other end is used for connection to the second end.
6. The detection circuit of the relay according to claim 5, characterized in that, The protection unit includes a Schottky diode, the positive terminal of which is connected to the end of the second sampling resistor used for connection to the second terminal, and the negative terminal is used for connection to the second terminal.
7. The detection circuit of the relay according to claim 5, characterized in that, The protection unit includes multiple Schottky diodes, which are connected in series between the second sampling resistor and the second terminal.
8. The detection circuit of the relay according to any one of claims 6-7, characterized in that, A balancing resistor is connected in series between the Schottky diode and the second terminal; When multiple Schottky diodes are provided, the balancing resistor is connected in series between the Schottky diode adjacent to the second terminal and the second terminal.
9. The detection circuit of the relay according to claim 8, characterized in that, When the voltage values of the first sampling voltage and the second sampling voltage are equal, the relay is determined to be in an open state; when the voltage difference between the first sampling voltage and the second sampling voltage falls within a preset voltage difference range, the relay is determined to be in a closed state.
10. The detection circuit of the relay according to claim 9, characterized in that, The preset differential pressure range is determined based on the resistance values of the pull-up resistor, the first sampling resistor, the second sampling resistor, and the balancing resistor.
11. A detection device, characterized in that, The detection circuit includes the relay as described in any one of claims 1-10.